This paper addresses the ways by which the releasing and deploying behaviors of a creased space membrane can be predicted accurately. Although existing studies have analyzed the released shape of a creased membrane by considering the elasto-plastic properties, the shape did not agree with the experimental results when the membrane was tightly creased. To examine the released shape of the membrane, creasing and releasing experiments are first conducted. The experimental results indicate that the opening angle of the crease increases with increasing elapsed time after the release due to stress relaxation. The stress relaxation behavior is predicted using finite element analysis (FEA) by considering the visco-elasto-plastic material properties. In addition, an analytical model of the releasing and deploying membrane has been proposed here. The results of the FEA and the analytical model indicate that the released angles are in good agreement with those in the experimental results. Thus, the effects of viscosity are considered important for predicting the releasing behavior of the space membrane.

For future large-scale structures with high accuracy, we have researched and developed an alignment monitor system. In particular, we have focused on the measurement of the relative positions of both ends of a one-dimensionally long structure such as the support structure of an X-ray telescope. The alignment monitor system consists of a laser source, a beam splitter, a retroreflector, and a PSD (Position Sensitive Device). The laser source and retroreflector are attached to the reference and target for which relative displacement is to be measured. The developed alignment monitor system was used for measurements in ground tests of a large astronomical observation satellite, and its usefulness was confirmed. To apply this alignment system to astronomical observations in space and the stratosphere, it is necessary to verify the compatibility with each environment. Therefore, the DemonstRation Experiment of Alignment Monitor (DREAM) were conducted on July 9, 2021 to evaluate the environmental compatibility of the alignment monitor system in the stratosphere for the future astronomical observation system of balloon experiments. The maximum altitude was 29 km, and the flight was for 2 hours 54 minutes. Due to the upper limit of the size of the gondola for balloon experiment, the laser source and the retroreflector were installed at a distance of 1m. Through the balloon experiment, it was confirmed that this alignment monitor system functioned normally in the stratosphere. In this experiment, artificial periodic thermal deformation of the structure was adopted to give a predetermined displacement to the measurement target (retroreflector) in the stratosphere. The difference between the displacement estimated from the measured temperatures and the displacement measured by this alignment monitor system was 0.4 μm RMS or less.

Laparoscopic surgery holds great promise in medicine but remains challenging for surgeons because it is difficult to perceive depth while suturing. In addition to binocular parallax, such as threedimensional vision, shadow is essential for depth perception. This paper presents an augmented reality system that draws virtual shadows to aid depth perception. On the visual display, the system generates shadows that mimic actual shadows by estimating shadow positions using image processing. The distance and angle between the forceps tip and the surface were estimated to evaluate the accuracy of the system. To validate the usefulness of this system in surgical applications, novices performed suturing tasks with and without the augmented reality system. The system error and delay were sufficiently small, and the generated shadows were similar to actual shadows. Furthermore, the suturing error decreased significantly when the augmented reality system was used. The shadow-drawing system developed in this study may help surgeons perceive depth during laparoscopic surgery.

Casting that comprises multiple parts with different thicknesses is prone to experience warpage deformation due to the non-uniform temperature distribution from the beginning of solidification to room temperature. This study is the first to investigate the effect of sand mold shake-out timing on the warpage deformation of a lamellar graphite gray cast iron casting with thick and thin geometries by both experiment and finite element analysis. It was found that warpage deformation was suppressed by 81.6% when the shakeout was performed just after A1 (austenite to ferrite) phase transformation temperature rather than after eutectic solidification temperature. The elastoplastic-creep analysis was proven to predict the warpage amount better than elastoplastic analysis, in which prediction error was reduced by 116%. The introduction of creep term that should not contribute to the work-hardening of the casting was assumed to relax the stress and suppress the warpage deformation; however, poor estimation of the creep properties at about 1000 degrees C to the A1 transformation temperature reduced the prediction accuracy. A sudden increase of warpage was observed and predicted during shakeout due to the release of the elastic strain that was accumulated as a result of sand mold constraint.

This paper proposes a wheel with a deployable leg that can change the apparent wheel radius to improve the runnability of a rover traversing a lunar surface covered with regolith. The driving force of the wheel was formulated according to terramechanics, and relations for the changing driving force with the different configurations were clarified. The simulated driving forces with the original wheel configuration and extended leg configuration were compared in a single-wheel experiment, and the results confirmed that the proposed extendable leg system exhibited a higher driving force than the original circular wheel. With this system, the rover can use the original wheel state for flat ground surfaces that do not require a high driving force and then switch to the proposed extendable leg system when a high driving force is required, such as escaping from local concave ground or climbing on steep slope. The proposed system is potentially applicable to efficiently traversing irregular surfaces not only on the Moon but also on other planets.

A shape of the satellite's solar sail membrane is essential for unloading angular momentum in the three-axis stabilized attitude control system because the three-dimensional solar sail can receive solar radiation pressure from arbitrary directions. In this paper, the objective is the shape optimization of a three-dimensional membrane-structured solar sail using the angular momentum unloading strategy. We modelled and simulated the solar radiation pressure torque, for unloading angular momentum. Using the simulation system, since the unloading angular momentum rate is maximized, the shape of the three-dimensional solar sail was optimized using a Genetic algorithm and Sequential Quadratic Programming. The unloading velocity in the optimized shaped solar sail was greatly improved with respect to a conventional flat or pyramid solar sail. (C) 2021 COSPAR. Published by Elsevier B.V. All rights reserved.

Drones, whose applications are rapidly expanding in recent years, have a wide range of uses, such as material transportation, pesticide spraying, structure inspection, and even the recently-flying cars, but it is difficult to fly in bad weather such as gusts. On the other hand, a CMG (Control Moment Gyro) is known which has the property of precessing when it is rotated by a force applied to the rotary shaft from the outside. Therefore, we wondered if the self-sustained control of the motorcycle using the CMG developed by the authors could be applied to the attitude control of the drone. In the paper, based on these findings, we modeled CMG and CMG-equipped drone based on the law of conservation of momentum, and the control law is obtained by using the optimal regulator method for the linearized model of the nonlinear system. The control effect has been confirmed by simulations. Based on the feedback gain confirmed by the simulation, the experiments have shown that CMG onboard drone are effective in suppressing wind disturbances equivalent to 22 m/sec and small vibrations of 0.7 to 4 Hz.

This study focused on the hierarchical modular approach to assembling space structures, which can be scaled up to increasingly larger sizes. This approach is based on dividing a large space structure into multiple modules, each with homogeneous automatic assembly functions. Hence, the overall structure can have diverse shapes and functions depending on the arrangement of modules, regardless of the size of the structure. Conventional approaches use locomotion and docking/release mechanisms installed on each module, but have been limited to 2-D shapes. In this study, a mechanism was developed that uses permanent magnets and electromagnets to assemble the space structure into any shape in three dimensions. The response surface method and downhill simplex method were used to optimize the size and arrangement of the magnets for efficient locomotion. The proposed mechanism was applied to a demonstration experiment to evaluate its effectiveness compared with existing methods.

Excessive tumour growth results in a hypoxic environment around cancer cells, thus inducing tumour angiogenesis, which refers to the generation of new blood vessels from pre-existing vessels. This mechanism is biologically and physically complex, with various mathematical simulation models proposing to reproduce its formation. However, although temporary vessel regression is clinically known, few models succeed in reproducing this phenomenon. Here, we developed a three-dimensional simulation model encompassing both angiogenesis and tumour growth, specifically including angiopoietin. Angiopoietin regulates both adhesion and migration between vascular endothelial cells and wall cells, thus inhibiting the cell-to-cell adhesion required for angiogenesis initiation. Simulation results showed a regression, i.e. transient decrease, in the overall length of new vessels during vascular network formation. Using our model, we also evaluated the efficacy of administering the drug bevacizumab. The results highlighted differences in treatment efficacy: (1) earlier administration showed higher efficacy in inhibiting tumour growth, and (2) efficacy depended on the treatment interval even with the administration of the same dose. After thorough validation in the future, these results will contribute to the design of angiogenesis treatment protocols.

In recent years, SiC power modules have attracted a lot of attention because they offer higher frequency and density as compared to the conventional Si power module. However high speed switching inevitably lead to the generation of surge voltage which may damage the power module. The design of layout, which composed of copper patterns, power semiconductors and terminals, is one of the factors that is necessary to overcome the problem. In this paper, the layout design of the half-bridge power module is optimized to reduce its internal inductance. The inductance was evaluated by electromagnetic field simulation.

Due to the demand for miniaturization, further improvement in cooling performance is required for power modules. The spiral-fin heatsink we considered has higher cooling performance than conventional ones. In this paper, we examined the design parameters of the spiral-fin, and found that three parameters of spiral-fin have big effect for the cooling performance

Trees are useful entities allowing to model data structures and hierarchical relationships in networked decision systems ubiquitously. An ordered tree is a rooted tree where the order of the subtrees (children) of a node is significant. In combinatorial optimization, generating ordered trees is relevant to evaluate candidate combinatorial objects. In this paper, we present an algebraic scheme to generate ordered trees with n vertices with utmost efficiency; whereby our approach uses O(n) space and O(1) time in average per tree. Our computational studies have shown the feasibility and efficiency to generate ordered trees in constant time in average, in about one tenth of a millisecond per ordered tree. Due to the 1-1 bijective nature to other combinatorial classes, our approach is favorable to study the generation of binary trees with n external nodes, trees with n nodes, legal sequences of n pairs of parentheses, triangulated n-gons, gambler's sequences and lattice paths. We believe our scheme may find its use in devising algorithms for planning and combinatorial optimization involving Catalan numbers.

This paper develops a haptic feedback control stick for remote control of a two parallel wheeled rover. The authors apply a bilateral controller for this remote operating-operated system in which their structures are different. Thus, the developed haptic feedback control stick plays a role as not only an input device to give the velocity information to the system but also an output device by which the operator feels an estimated external force applied to the wheel of the rover. The haptic feedback control stick is strongly expected the operator can control the operated rover more intuitively and more safely. In this paper, the authors experimented by combining a linear-slide-type control stick and a single wheel computer simulator of the rover. However, the operator felt a force except the estimated force to the rover's wheel, in conditions that a time delay occurred because of a large dynamical difference between the control stick and the rover. Therefore, two types of experiments were compared, i.e., one used only the bilateral control and the other used switching the bilateral control and the force control according to a value of the time delay. These experimental results were discussed and evaluated as focusing on a situation when a time delay occurred.

This paper presents a remote control between a haptic feedback control stick and a wheel of a two-parallel-wheeled rover. It is well-known that the operator's operability was improved largely by haptic information reproduced on the stick using the bilateral control. This haptic information corresponds to disturbance force/torque applied to the wheel of the rover. When the disturbance is estimated using the disturbance observer (DOB), its estimated value includes not only an external force, viscous resistance, Coulomb frictional force, and a force by a modelling error, but also a restoring force. The restoring force is a force occurring when an operating-operated robot system is synchronized by a position control. It often becomes a problem of the bilateral control using two robots with a dynamically-different structure. Particularly, our experimental system in this paper has a very large dynamical difference. In other words, there exists a fairly-large time delay between them. The DOB of the operating robot estimates a value including this restoring force. Intuitively, this seem to prevent the operator from feeling sensitively other forces applied to the wheel such as the external force. However, on the same time the authors think this restoring force is very important for the operator to know situations of the remote rover, e.g., whether it drives with the speed given as a command value or not. In this paper, we proposes a positional gain adjusting bilateral control method in order not to prevent the restoring force from feeling the external force and so on. The proposed method was experimented for verification. Experimental results were discussed and evaluated comparing to the following two cases: one is when a positional gain of the operating robot is reduced as the difference increases, and the other is when that of the operated robot is enhanced contrarily as the difference increases.

Anthropomorphic test devices (ATDs) are useful for simulating human damage during traffic accidents. For large accidents such as train accidents, experiments using full-size ATDs are not feasible because of cost, space, and time requirements. However, it is difficult to develop small-scale ATDs because changes in geometry are not necessarily accompanied by commensurate changes in mass or force. In this study, we designed and developed small-scale human dummies using the similarity rule. We determined the similarity ratio and focused on the neck, chest, and abdomen, which are important for protecting organs and nerves. Drop, impact, and sled tests based on ISO TR9790 indicators were used to evaluate the ATD. The first ATD scored 4.69, which indicates "fair biofidelity"; the neck and chest delivered low scores during the sled and impact tests, respectively. We simulated the behavior of the ATD using finite element analysis; the experimental and analytical values were consistent. We modified the neck and chest parameters using simulation results and evaluated the optimized ATD using impact and sled tests. The optimized ATD scored a 6.56, which indicates "good biofidelity." In conclusion, we developed a small-scale ATD capable of satisfactorily simulating human behavior. Using the proposed ATD, we can reduce the opportunities for full-scale experiments.

This research deals with hierarchical modular structure which is noted as the assembly method in view of the recent upsizing of space structures. The idea is dividing a large space structure into multiple modules and homogeneous automatic assembly functions are installed on each of a module. Hence the shape and function of the entire structure has diversity as they can be changed by the arrangement of modules, regardless of the size of the structure. The conventional researches of locomotion and docking / release mechanisms installed on each module and keeping such characteristics are limited to two-dimensional. In this research, we propose a mechanism using an electromagnet that can be assembled into any shape in three dimensions. The size and arrangement of the electromagnet are optimized to maximize its movement performance by using the Response Surface Method (RSM) for making response surface and applied downhill simplex method. On that basis, the demonstration experiment was actually carried out and the success rate was compared with the existing method to demonstrate the effectiveness of the proposed method.

This paper presents a method to inspect the interior of a winding small gas pipe using a hollow guide wire. There is no conventional method to insert an endoscope into an 8-bend 25-mm-diameter gas pipe within 2 hours. In medical practice, a guide wire inserted in advance enables insertion of a catheter into a vessel. However, it is impossible to insert a normal guide wire into a gas pipe because the wire buckles in the pipe. Thus, we designed a hollow guide wire with a small front diameter and large rear diameter, making the front soft and the rear stiff. This guide wire can be inserted without buckling or meandering. First, we measured mechanical properties such as the torsional spring constant and damping coefficient of the wire and the frictional coefficient between the pipe and wire. Second, we conducted an experiment inserting guide wires with various tip pitches, front lengths, front outer diameters, and rear outer diameters. Third, we analyzed the insertion distance by simulating guide wire insertion using the Lagrange method, and optimized the guide wire shape via the response surface method. Finally, the optimized guide wires were tested experimentally to validate the analysis. As a result, an optimized guide wire and an endoscope can both be inserted into a gas pipe and removed within just 3 minutes.

Elucidating versatile configurations of spiral folding, and investigating the deployment performance is of relevant interest to extend the applicability of deployable membranes towards large-scale and functional configurations.In this paper we propose new schemes to package flat and curved membranes of finite thickness by using multiple spirals, whose governing equations render folding lines by juxtaposing spirals and by accommodating membrane thickness. Our experiments using a set of topologically distinct flat and curved membranes deployed by tensile forces applied in the radial and circumferential directions have shown that (1) the multi-spiral approach with prismatic folding lines offered the improved deployment performance, and (2) the deployment of curved surfaces progresses rapidly within a finite load domain. Furthermore, we confirmed the high efficiency of membranes folded by multi-spiral patterns.From viewpoints of configuration and deployment performance, the multi-spiral approach is potential to extend the versatility and maneuverability of spiral folding mechanisms. (C) 2020 COSPAR. Published by Elsevier Ltd. All rights reserved.

The estimation of grasp states in myoelectric prosthetic hands is relevant for ergonomic interfacing, control and rehabilitation initiatives. In this paper we evaluate the possibility to infer the grasp state of a prosthetic hand from RGB frames by using well-known deep learning architectures in testing scenarios involving variations of brightness, contrast and flips. Our results show the feasibility, the attractive accuracy and efficiency to estimate prosthetic hand poses with a GoogLeNet-based deep architecture using relatively few training frames.

Path planning with smoothness considerations is of relevant interest to ensure the safety and the comfortability of passengers in mobile and vehicle navigation. In this paper, we present our preliminary results in computing smooth paths from observed mobile robot trajectories. Our approach enables the generation of alternative paths safer paths for navigation, and is potential to extend towards the fitting and fairing of curves with utmost efficiency.

Laparoscopic surgery can realise minimal invasive surgery. However, it's difficult for surgeon to recognize the depth during suturing. Binocular endoscope helps surgeons to recognize the depth, but surgeons do not understand the circumstance by equipping with head mounted display. Since shadow helps surgeon to recognize the depth, in this paper, we developed the virtual shadow drawing system. The system shows shadow like actual by the estimation of the forceps position, surface shape and shadow's position. We tested the accuracy of the system by evaluating the estimated distance and angle between the forceps and the surface. The error and delay were enough small to draw shadow like actual. Furthermore, participants performed the suturing task while looking at the shadow. The experiment was carried out in a variety of the shadow's direction. As result, the suturing error's mean and variance value was the least at the 270 deg. In conclusion, the appropriate shadow would be vertical to the wounds.

Mobile robots have recently attracted the attention and applicability in field areas ubiquitously. Within the context of autonomous navigation, path planning is relevant for comfortability, safety, execution time and energy savings. In this paper, we propose an approach to suggest smooth paths from observed robot trajectories by optimizing fitting and smoothness criteria using Differential Evolution with distinct modes of initialization, selection pressure, exploration and exploitation. Our rigorous computational experiments using a relevant set of real-world robot trajectories from the Boe-Bot mobile robot architecture show the feasibility and efficiency of our approach in computing smooth curves, suggesting the superior performance of the greedy initialization scheme based on the triangular convex hull of the robot trajectory, and Differential Evolution with exploitative and parameter adaptation schemes such as Rank-Based Differential Evolution (RBDE), Adaptive Differential Evolution with External Archive (JADE) and Strategy Adaptation Differential Evolution (SADE). Our obtained results offer the building blocks to further advance towards developing data-driven curve fitting and path planning algorithms, which may find use in several real-world applications in Robotics and Operations Research.

© 2019, The Author(s). Breast cancer diagnosis has been mostly accomplished through imaging. These methods have great advantages in being able to detect the presence and location of breast cancer. However, it is difficult to distinguish between a benign and malignant tumor located in a deep position because both tumor types look similar. In this paper, tissue including the tumor from skin was vibrated using a compression cylinder, to analyze the frequency difference for distinguishing tissue type. Before distinguishing between a benign and malignant tumor, it is necessary to validate that the difference between normal tissue and tumor can be distinguished. The objective of the study is to validate the feasibility to emphasize the frequency differences in a 10.0 mm or greater deep tumors during vibration by pushing a cylinder towards the deep tumor. A phantom model and finite element analysis model were constructed to simulate the breast. In the experiment, air was injected into the phantom and the displacement was measured. The frequency response for distinction of tissue types was analyzed and it was found that the displacement difference rate was over 50% at a frequency of 130 Hz when the cylinder was pushed into the sample as opposed to when not pushed in. Changes in displacement were measured according to the distance between the tumor and vibration point using finite element analysis. When the measurement and vibration points were on the center of the tumor, the difference in the resonance point was at its largest (5.5 Hz). Results show that the position of a tumor could be easily and rapidly detected by vibrations from a cylinder pushed into the diagnostic site.

© 2019 IEEE. Recent driving assistance technologies such as Electronic Stability Control (ESC) and auto brake system release drivers from complicated driving tasks. On the other hand, there is concern that it reduces pleasure feelings of a driver if these system's behaviors are different from the driver's intention. To avoid such problem, it is important to evaluate the driver's intention and decision-making process, and design the assistance system to fit it. In this research, we propose an unsupervised reinforcement learning driver model based on human cognitive mechanism and human brain architecture. Because this study's objective is to analyze the process of driving decision making, we hire a simple actor-critic model as a driver model. We set learning parameters from the driver's decision making characteristics which are derived from the task execution process of the human brain, and set state space from driver's sensory characteristics. This driver model can predict lane change decision making adequately and shows high accuracy (ACC=94%) on verification tests with real driving data. This result is similar to unpublished results of a deep neural network driver model which use the same data as teaching data. From these results, we consider that the proposed reward function and learned state space represent the driver's decision making characteristics.

Biomimetics present useful ideas for various product designs. However, most biomimetics only mimic the features of living organisms. It has not been clarified how a given shape is attained through natural selection. This paper presents the design factors that optimize the radula shape of Euhadra peliomphala. Clarifying the important design factors would help designers in solving several problems simultaneously in order to adapt to complicated and multi-functionalized design mechanisms. We measured the radula of Euhadra peliomphala by using a microscope and modeled the grinding/cutting force using the finite element analysis (FEA). We reproduced the natural selection using multi-objective genetic algorithm (MOGA). We compared the solutions when optimizing the radula shape using objective functions of each combination of stress, cutting force, abrasion, or volume. The results show that the solution obtained through two-objective optimization with stress and cutting force was the closest to the actual radula shape.

Large space structures tend to be flexible because only a few dimensions become large while material properties become constant. For flexible structures, even minute disturbances affect the movement of the structure. For the sake of precise observation in space, large structures with stable dynamic properties are required to support sensors. The stability of the structures is affected by the thermal expansion caused by solar radiation. The purpose of this research is to verify the compatibility between numerical analyses and experimental results for a mast structure with thermally induced stick-slip phenomenon at friction sliding part. Radiation heating experiments for the mast structure, and numerical analyses using finite element method with several friction models at contact surface among parts in the mast were discussed. Three friction models are: (a) coulomb model, (b) simplified coulomb model, and (c) rising static friction model. Comparing each friction model, modeling on thermally induced stick-slip occurring in the space structure is studied. The coulomb model and the rising static friction model showed thermally induced stick-slip behavior. However, the simplified coulomb model did not show such behaviors. Finally, several methods were proposed to decrease the disturbance due to thermally induced stick-slip.

© copyright Environment and Climate Change Canada. In this paper, we proposed a wheel equipped rover with deployable legs that can change the apparent wheel radius in order to improve the runnability of the rover which travels on the ground covered with lunar regolith. Furthermore, we formulated the driving force of the wheel based on Terramechanics and clarified the mechanism of the driving force change using our proposed rover wheel. In addition, the driving force was compared between the original wheel configuration and the leg expanded one in single wheel running experiments, and it was validated that the proposed leg expandable system exhibits higher driving force than the original circular wheel. With this system, in the case of a flat ground surface that does not require a high driving force, the vehicle should use the original wheel state, and when a high driving force is required such like the situation the vehicle need to escape the wheel from the local concaved ground, the proposed expandable leg system can be useful, and then the possibility of traveling on irregular surface efficiently not only on the moon but also on other planets was shown.

© 2019 Design Society. All rights reserved. In recent years, product complexity in terms of function and structure has been driven by technological development in complementary components. Designing unbiased product evaluation metrics being to grasp the complex relationships of product features, and able to capitalize on market needs has become a challenge in industrial practice. In this paper, we propose a hybrid framework in which evaluation models are generated by integrating Interpretive Structural Modeling (ISM), Hierarchical Clustering and Data Envelopment Analysis (DEA). Whereas ISM constructs hierarchical digraphs (skeletons), Hierarchical Clustering reduces dimensionality of pairwise comparisons (correlations) of design variables, and suggests possible evaluation configurations, and DEA computes weights to provide optimal evaluation metrics. Our computational experiments using more than twenty thousand vehicles from 1982 to 2013 confirmed the feasibility and usefulness of DEA with hierarchical concepts to generate the optimal vehicle evaluation metric, and to suggest configurations for vehicle design layouts.

© 2019 Design Society. All rights reserved. Pipe inspection robots have been developed to reduce the cost and time required for gas pipe inspection. However, these robots have been developed using a scrap and build method and are not used in practice. In this paper, we propose a method of virtual pipe inspection simulation to clarify the parameters that are important in increasing the robot's ease of use. This paper presents the results obtained by a feasibility study with regard to pipe simulation. We developed a virtual pipe by simulating eight actual turns of an external gas pipe, and a robot equipped with camera at the tip. In the experiments, three individuals working in the field of gas inspection carried out the operation. We obtained questionnaire, time, and brain activity data. The results revealed various important points that must be considered in practical simulation and robot design. In conclusion, the virtual pipe simulation can be useful in developing the design of a pipe inspection robot.

<p>For future advanced missions, large and highly accurate space structures are required. A prior shape adjustment of the structure before launch is not sufficient to achieve such accurate space structures. For example, thermal deformation on orbit cannot be eliminated by the preliminary adjustment of the structure. Therefore, the shape control of the structure is a promising technique for highly accurate space structures. For the shape control, the shape error should be measured on-orbit. In this study, a measurement system for the displacement of a slender space structure has been developed as an alignment monitor. The characteristics of this measurement system are long working distance and simple configuration. The measurement system consists of a laser, retro-reflector and positioning sensing device. The performance on the ground was already demonstrated through the satellite ground test. As a first step to on-orbit experiment, the demonstration experiment on the balloon is planned. In this paper, the system configuration and development progress are reported.</p>

In recent years, there have been increasing the number of power modules which is required with high performance, miniaturization and weight saving. But these requires cause high heat generation density for power module, which gets junction operation temperature to rise. Cooling unit is thus greatly demanded for high heat dissipation. The simple shaped heatsinks (straight-fin type and pin fin type) were generally used. But they have the limit of cooling performance. In this report, we have developed new heatsink shape to cope with rapidly increasing of the cooling requirement. Cooling performance is shown to thermal resistance and pressure loss. We evaluated them by thermal fluid analysis. In this approach, the spiral-fin heatsink with spiral curved channels has excellent cooling performance. This shape is the unique point in this report. This is because the shape with three-dimensional regular curve has not been studied. The spiral-fin heatsink has many factors (tin thickness, fin pitch, the number of channels, etc.). These factors affect cooler performance. We changed these factors to determine the best shape of spiral-fin. As a result, the best shape is 14.9[%] lower than the straight-fin type in thermal resistance.

<p>In this study we propose the use of spiral folding to deploy automotive airbags, and propose the folding pattern considering creases, which has the potential benefits to diminish friction during storage and bring benefits to faster deployment. Our preliminary experiments show the feasibility to deploy airbags by using the spiral folding approach, and the reasonable consistency between the modeling and real-world deployment. Our results offer preliminary insights for further study on spiral folding mechanisms and safest deployment performance.</p>

<p>This paper presents a surgical robot mechanism optimization method considering of the working error and operator's muscle burden. The virtual surgical system was developed to simulate the visual and haptic feedback. The participants operated the VR surgical simulation system while the authors measured the working error and the participant's joint motion. The histogram was made of the data to show the distribution. The authors estimated the appropriate probabilistic distribution model using Akaike's Information Criterion (AIC) method. As a result, there were many cases most applicable to the Weibull model.</p>

© 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. This research formulates the two-dimensionally model of a membrane with crease line which is always added when the thin material is used for deployable space structure like a solar sail. Recent space development is tending to focus on installing a system on a ultra-light weight structure, so when the membrane is chosen as the base of space structure, the keeping accuracy of the membrane surface is the point of interest. This means how to reduce the wrinkle appeared on the membrane becomes the key point. However, the most research on modelling the membrane limit to the one dimension model, or if any, the plastic deformation is not considered. Here in this paper, the authors established the two-dimensionally membrane model considering the plasticity and clarified from analysis and experiment that wrinkles can be reduced by giving crease to a membrane. In the model assuming the actual antenna installed structure and with the actual load condition, the fact is obtained that a crease perpendicular to the loading direction should be applied to a position one fifth between the load application point and the wrinkle generated region. This position can be considered to be able to reduce wrinkle the most from the view point of amount of energy required to eliminate wrinkles.

This article proposes a novel dexterous endoscopic parallel manipulator for minimally invasive surgery. The proposed manipulator has 3 degrees of freedom (3-DOF), which consist of two rotational DOFs and one translational DOF (2R1T DOFs). The manipulator consists of 3 limbs exhibiting identical kinematic structure. Each limb contains an active prismatic joint followed by 2 consecutive passive universal joints. The proposed manipulator has a unique arrangement of its joints' axes. This unique arrangement permits large bending angles, ±90° in any direction, and a workspace almost free from interior singularities. These advantages allow the proposed manipulator to outperforms existing surgical manipulators. However, this unique arrangement makes the analysis of the robot extremely difficult. Therefore, a geometrical/analytical approach is used to facilitate its singularity analysis. Construction of the virtual prototype is accomplished using ADAMS software to validate the proposed manipulator and its bending capability. A closed-form solution for inverse kinematics is obtained analytically. Also, the forward kinematics solution is obtained numerically. Moreover, evaluation of the workspace is achieved using motion/force transmissibility indices. A practical experiment has been performed using a scaling technique and PID controller. The experimental results show the feasibility of the teleoperated surgical system using the proposed parallel manipulator as the slave.

Optimal topologies in networked systems is of relevant interest to integrate and coordinate multi-agency. Our interest in this paper is to compute the root location and the topology of minimal-length tree layouts given n nodes in a polygonal map, assuming an n-star network topology. Computational experiments involving 600 minimal tree planning scenarios show the feasibility and efficiency of the proposed approach.

Combinations of m out of n are ubiquitous to model a wide class of combinatorial problems. For an ordered sequence of combinations, the unranking function generates the combination associated to an integer number in the ordered sequence. In this paper, we present a new method for unranking combinations by using a gradient-based optimization approach. Exhaustive experiments within computable allowable limits confirmed the feasibility and efficiency of our proposed approach. Particularly, our algorithmic realization aided by a Graphics Processing Unit (GPU) was able to generate arbitrary combinations within 0.571 seconds and 8 iterations in the worst case scenario, for n up to 1000 and m up to 100. Also, the performance and efficiency to generate combinations are independent of n, being meritorious when n is very large compared to m, or when n is time-varying. Furthermore, the number of required iterations to generate the combinations by the gradient-based optimization decreases with m in average, implying the attractive scalability in terms of m. Our proposed approach offers the building blocks to enable the succinct modeling and the efficient optimization of combinatorial structures.

Being ubiquitously used as anti-adhesive and wound-covering mechanisms, thin films have potential therapeutic uses as cell sheets to target inner organs while navigating narrow environments. A significant challenge to realize versatile films lies in achieving compact storage and efficient transport while ensuring coherency in curvature-bounded environments. In this paper, we propose a folding mechanism of a curved film by using a spiral approach, enabling efficient unfolding and flexible plasters with curved surfaces. Our experiments using gelatin-based films with curved surfaces shows the superior indwelling ability in terms of chromaticity level compared to the conventional planar films, as well as the efficient unfolding in the order of seconds. Our results presents the theoretical and experimental building blocks to realize a versatile class of films which are able to navigate narrow environments, and unfold efficiently and flexibly.

The advance of driving assistance technologies such as Electronic Stability Control (ESC) or auto break system, drivers are released from complicated driving tasks. On the other hand, there is concern that it reduces pleasure feelings of a driver if these system's behaviors are different from the driver's intention. To avoid such problem, it is important to evaluate the driver's intention and decision-making process, and design the assistance system to fit it. Although methods such as sensory subjective evaluation are commonly used, the human cognitive mechanism design behind them is not yet fully understood. In this paper, we introduce a novel method for evaluating driver's decision-making process based on the numerical simulation of the driver's behavior. By using this method, the assistance system can substitute the driver appropriately and driver can accept the system's maneuver because which is same as the driver's intention. As an example of this method we evaluate the relationship between decision-making timing and estimation time length of the driver's model. One possible method to simulate the driver's decision-making is machine learning. Reinforcement learning has been studied for simulating the human's brain function to learn and decide as action and state model. We used machine learning to create the reinforcement learning driver model, and a simple vehicle simulation model which are combined as a human-vehicle model. We used the simple vehicle and driver model because the aim of this research is to investigate whether the driver's decision-making process can be simulated or not. Then the model is simulated to learn to drive on a highway with 3 lanes and other vehicles. The simulated driver made some single lane change to pass a slower vehicle in front or to go out from highway at an interchange. Results showed that the decision-making timing depend on the estimation time of the reinforcement learning model. We exposed that the model behaves similar to general driver's behavior when the estimation time was settled as 7sec which is derived from human brain's cognitive mechanism. In conclusion, our simulation model based on human cognitive mechanism can simulate the driver's lane change decision- making behavior adequately.

Due to the absence of mechanical contact, active magnetic bearing can be electrically controlled in an accuracy of a micrometer. This makes it a good choice to be used for robot manipulation in the micrometer scale, especially in environments that need to be very clean, for example, surgery or clean rooms. Moreover, it can be used in the applications that need high precision micromotion such as semiconductor wafers manipulation. Despite all these benefits, there are few studies that have investigated the application of active magnetic bearing in the robotics field in spotless environments for micromotion applications. This article proposes a new novel six-degree of freedom two-link manipulator using two contactless joints with active magnetic bearing. The key design aspects of the proposed manipulator are presented. The proposed manipulator is designed using finite element method. Each joint roll angle is controlled using a PID-based feedback linearization controller, while a state feedback controller with integral term is used for controlling the active magnetic bearing five-degree of freedom. The stability analysis of the system, under the proposed controller, is carried out. The robustness of the controllers is tested against end effector payload variations. The results demonstrate that the proposed two-link manipulator is feasible and valid for the applications in spotless environments that need high precision accuracy micromotion control. These significant findings have indicated the feasibility of implementing this proposed manipulator in practice and open the door for developing other types of robots with complete contactless joints using active magnetic bearing.

This paper affords dynamic modeling and control for a new 3D pantograph manipulator. The new manipulator possesses pure decoupled translational motions and it is characterized by large workspace to size ratio, high speed, rigidity, and accuracy. Euler-Lagrange first type method is used to get the dynamic model. However, the resulted dynamic model is too complex to be used in model-based control techniques. Therefore, a simplified nominal plant is proposed. It allows the inverse dynamic solution efficiently. However, an explicit form of the nominal Coriolis and centrifugal matrix cannot be obtained due to the complicated kinematic terms. Considering these dynamic characteristics as well as the required robust trajectory tracking performance of the manipulator, a new controller is proposed. The new controller is called inverse optimal PID with Feed-Forward Control which is designed in H-infinity framework. The new controller has the following merits; robustness, optimality, simple implementation, and efficient execution without the need of explicit forms of dynamic matrices. The extended disturbance in the proposed controller is smaller than that in the inverse optimal PID control (IPID) and contains one type of error contrary to the nonlinear robust motion controller (NRIC). The performance of the proposed controller is compared with those of IPID and NRIC controllers for different trajectories and payloads. The dynamic simulation results via co-simulation of MSC-ADAMSA (R) and MATLABA (R)/Simulink software prove the robustness of the proposed controller against speed/payload variations. The proposed controller is found to have higher performance compared with IPID and NRIC controllers. These results assure the feasibility of the 3D pantograph manipulator with the proposed controller for pure translational tracking applications.

Accurate estimation of needle deflection is necessary to successfully steer the needle to targets located deep inside the body. In particular, the deflection that occurs until the tissue surface is breached differs according to the tissue shape and stiffness. This topic has not been a focus of previous work. In the present paper, we propose a model with which to estimate the needle deflection that occurs until breaching of the tissue surface with consideration of the tissue shape and stiffness. This model comprises a cantilever beam supported by virtual springs that represent the interaction forces between the needle tip and tissue surface. The effects of different insertion angles and tissue stiffness on needle deflection are represented by changing the spring constants. The model was used in experiments involving four different insertion angles (0A, 15A, 30A, and 45A) and three different polyvinyl chloride (PVC) phantoms with different stiffness (100, 75, and 50%). We verified the proposed model with the 80% PVC phantom and showed a maximum error of 0.04 mm.

Huge lava tubes with an approximate diameter of 65-225 m were found on the surfaces of Moon and Mars in the late 2000's. It has been argued that the interiors of the caves are spacious, and are suitable to build artificial bases with habitable features such as constant temperature, as well as protection from both meteorites and harmful radiation. In line of the above, a number of studies which regard the soft landing mechanisms on the bottom of the lava tubes have been proposed. In this paper, aiming to extend the ability to explore arbitrary surface caves, we propose a mechanism which is able to reach the ceiling of lava tubes. The basic concept of our proposed mechanism consists of a rover connected to an oscillating sample-gatherer, wherein the rover is able to adjust the length of the rope parametrically to increase the deflection angle by considering periodic changes in the pivot, and thus to ease the collection of samples by hitting against the ceiling of the cave. Relevant simulations confirmed our theoretical observations which predict the increase of deflection angle by periodically winding and rewinding the rope according to pivotal variations. We believe the our proposed approach brings the building blocks to enable finer control of exploration mechanisms of lava tubes and narrow environments.

Breast cancer diagnosis has been mostly accomplished by imaging technologies. These methods have the great advantages of detecting the presence and location of breast cancer. However, it's difficult to distinguish between a benign and malignant tumor in a deep position because both tumor types look similar. In this paper, we vibrated the tissue including tumor from skin with a compression cylinder to analyze the frequency difference for distinguishing the tissue type. Before distinguishing a benign and malignant tumor, it's necessary to validate to distinguish between normal tissue and tumor. The objective is to validate the feasibility of using a compression cylinder that emphasizes the differences in frequency between normal tissue and tumor. In two experiments, we measured the displacement on the surface of a breast phantom vibrated by an impulse hammer. We compared the frequency difference with and without a cylinder. We also studied the frequency changes in the relationship between tumor and cylinder position. We found a 5.0 Hz difference in compliance between normal tissue and the simulated tumor using a compression cylinder. The difference in frequency correlated negatively with distance from the simulated tumor to a compression cylinder. We concluded that a compression cylinder would enhance the frequency difference between normal tissue and a simulated tumor with appropriate configuration.

Laparoscopic surgery has the advantage of the minimally invasive for patients. However, the surgery is technically difficult for surgeon because high dexterity is required for suturing in the narrow patient's body. This paper presents a sealing method to locate the adhesive plaster at the incision instead of suturing. The objective is to optimize the plaster material and structure. We made the plaster with the thermally cross-linked gelatin film in a spiral fold because thermally cross-linked gelatin film has the high biocompatibility and tackiness, and a spiral fold has great storage efficiency. In 3 experiments, we measured expansion rate, expansion tension, peeling force, and sealing pressure in a variety of gelatin volume and concentration, and the films diameter. From these experimental results, we optimized the films using response surface method. As a result, the plaster is optimal at gelatin volume 10 mL, gelatin concentration 4 wt %, and films diameters 75 mm. We concluded that the optimized spiral folded adhesive plaster is sufficient in terms of the expansion, tackiness, and sealing properties.

<p>In this paper, in order to develop a structure capable of coping with trend in large scale and the diversification of the space structure in recent years. We will propose a moving mechanism using electromagnets and permanent magnets. We make a real machine as a self-construction system that automatically joins and assembles to the target shape after dividing a large space structure into some modules and conveying them to outer space over several times. We confirmed the reliability of moving mechanism for modular space structure proposed in this paper by giving a success rate of movement completion through an experiment.</p>

A new sink should be in simple shapes for reasonable manufacturing process. On the other hand, the heat sink tends to be complicated shape for high cooling performance. Recently, 3D printer is able to process complicated shapes. However, manufacturing cost by 3D printing method is expensive. Thus it is important to verify and improve fluid flow and thermal conductivity at the design stage of the heat sink. This study provides a simulation model and a new high performance heat sink by using finite element method and using optimization method. The new heat sink decreases the thermal resistance about 15% in comparison with the conventional one.

Fluxless bonding of plateless Cu-Cu substrates at processing temperature lower than 250 A degrees C and low pressure of 0.1 MPa was achieved by transient liquid phase sintering (TLPS) of mixed Cu nanoparticles and Sn-Bi eutectic powders. The effects of mixture composition, and sintering temperature on the shear strength, microstructure, and remelting temperature were investigated. Lowering the sintering temperature of Cu mixed with 65 weight percentage of Sn-Bi (Cu-65SnBi) resulted in decreased shear strength, however, at 200 A degrees C sintering temperature, the obtained highest shear strength was more than 20 MPa. It was found that it is essential to use Cu nanoparticles to accelerate the consumption so that no initial Sn-Bi phases remained after processing. The liquid phase generated at approximately 196 A degrees C during sintering from the reaction between newly formed Cu6Sn5 and Bi-phase was expected to facilitate the densification and strengthening of the joints. Although this newly generated liquid phase was known to solidify as hypereutectic Sn-Bi, by controlling the sintering temperature at 200 A degrees C, the remelting event at 139 A degrees C was not observed by differential scanning calorimetry. It is assumed that the proportion of solidified Sn-Bi eutectic phases in Cu-65SnBi that was sintered at 200 A degrees C were significantly small, hence, when reheated at 150 A degrees C, the obtained shear strength was equivalent to that at room temperature.

In this paper we aim at tackling the problem of searching for novel and high-performing product designs. Generally speaking, the conventional schemes usually optimize a (multi) objective function on a dynamic model/simulation, then perform a number of representative real-world experiments to validate and test the accuracy of the some product performance metric. However, in a number of scenarios involving complex product configuration, e.g. optimum vehicle design and large-scale spacecraft layout design, the conventional schemes using simulations and experiments are restrictive, inaccurate and expensive.
In this paper, in order to guide/complement the conventional schemes, we propose a new approach to search for novel and high-performing product designs by optimizing not only a proposed novelty metric, but also a performance function which is learned from historical data. Rigorous computational experiments using more than twenty thousand vehicle models over the last thirty years and a relevant set of well-known gradient-free optimization algorithms shows the feasibility and usefulness to obtain novel and high performing vehicle layouts under tight and relaxed search scenarios.
The promising results of the proposed method opens new possibilities to build unique and high performing systems in a wider set of design engineering problems. (C) 2017 Elsevier B.V. All rights reserved.

Understanding the rheological properties of soft biological tissue is a key issue for mechanical systems used in the health care field. We propose a simple empirical model using fractional dynamics and exponential nonlinearity (FDEN) to identify the rheological properties of soft biological tissue. The model is derived from detailed material measurements using samples isolated from porcine liver. We conducted dynamic viscoelastic and creep tests on liver samples using a plate-plate rheometer. The experimental results indicated that biological tissue has specific properties: (i) power law increase in the storage elastic modulus and the loss elastic modulus of the same slope; (ii) power law compliance (gain) decrease and constant phase delay in the frequency domain; (iii) power law dependence between time and strain relationships in the time domain; and (iv) linear dependence in the low strain range and exponential law dependence in the high strain range between stress-strain relationships. Our simple FDEN model uses only three dependent parameters and represents the specific properties of soft biological tissue.

The differentiation and the integration of products are the essential procedures for product innovation. To understand the product innovation, the approaches using S-curve theory, which explain the evolution of a technological system, have been effective. However, the S-curve theory has the disadvantage that the validity of the analysis depends greatly on the number of data. In this paper, we propose a novel method for measuring and predicting the technological innovation and the product evolution based on the S-curve and wavelet transform to solve the problem. In order to confirm the effectiveness of the proposed method, we will conduct a case study using patents of air purifiers. Furthermore, we will define and support the differentiation and the integration of the mechanical structure using the proposed method. Our analysis shows that the differentiation and the integration of the mechanical structure occur as a life cycle extension after the main technologies enter the declining phase. Therefore, the incidental technologies should be introduced at the beginning of the declining phase of the main technologies.

Route bundling implies compounding multiple routes in a way that anchoring points at intermediate locations minimize a global distance metric. The result of route bundling is a tree-like structure where the roots of the tree (anchoring points) serve as coordinating locus for the joint transport of information, goods, and people. Route bundling is a relevant conceptual construct in a number of path planning scenarios where the resources and means of transport are scarce/expensive, or where the environments are inherently hard to navigate due to limited space. In this paper we propose a method for searching optimal route bundles based on a self-adaptive class of differential evolution using a convex representation. Computational experiments in scenarios with and without convex obstacles show the feasibility and efficiency of our approach.

This paper aims at computing minimal-length tree layouts given an n-star graph in a polygonal map. This problem is strongly related to the edge bundling problem, which consists of compounding the edges of an input graph to obtain topologically compact graph layouts being free of clutter and easy to visualize. Computational experiments using a diverse set of polygonal maps and number of edges in the input graph shows the feasibility, efficiency and robustness of our approach.

Graphs with self-loops enable to represent a large variety of interactions in natural and artificial systems, allowing not only inter-connectivity among heterogeneous entities but also the self-dependence of entities, e.g. the recursive and autonomous nature of dynamical systems. In this paper we present new bijective constructs which enable the numerical representation of graphs with self loops (or loopy graphs). In particular, we study the case of (1) undirected and (2) directed graphs with n nodes and m edges with self-loops. Our proposed approach realizes the succinct representations by using integer numbers in which rigorous computational experiments show the efficiency of our proposed algorithms: the complexity follows a quasilinear behaviour as a function of the number of edges (which is independent of the number of nodes). Furthermore, as direct consequence of our constructs, we propose list structures having O(m) space complexity, which realize the linear space complexity depending only on the number of edges (the list is independent of n). We believe that our bijective algorithms are useful to tackle problems involving sampling of graphical models, network design as well as process planning by using number theory and sample-based learning.

In this work, low temperature of 200 degrees C, low pressure of 0.1MPa, fluxless and plateless Cu-Cu bonding in SiC power module is achieved by the transient phase liquid sintering (TLPS) of Cu nano particle and Sn-Bi eutectic powder. In this paper, shear strength at room temperature and 150 degrees C of two compositions of Cu mixed with Sn-Bi is investigated and the factor influencing the shear strength at 150 degrees C is examined by means of differential scanning calorimetry (DSC). In 70 mass% added Sn-Bi (Cu-70SnBi), which was sintered at 200 degrees C, the remelting event at 139 degrees C occurred due to the residual Sn-Bi eutectic phase and assumed to result in the decrease of shear strength at 150 degrees C. On contrary, in 65 mass% added Sn-Bi (Cu-65SnBi), which was sintered at the same conditions, remelting event at 139 degrees C was not observed, and the obtained shear strength at 150 degrees C was almost similar to that of at room temperature (R. T.).

A new decoupled 3D translational pantograph manipulator with symmetrical design is proposed. Since its three linear actuators are placed on/near the base, it possesses, to some extent, the advantages of parallel manipulators such as high speed, high stiffness and high accuracy. Since its structure is close to that of serial manipulators, its workspace to size ratio is high, comparable to that of serial manipulators. Moreover, the end-effector of the proposed manipulator has decoupled translation motions in three perpendicular directions with fixed orientation. Also, the manipulator has a linear input/output relationship for the positioning problem. Other possible architectures for the proposed manipulator are presented where the manipulator can have 4, 5 or 6 DOFs. The unconventional interconnected structure of the proposed manipulator does not allow the use of known mobility analysis methods. So, a novel method based on sketching the 3D velocity diagram is developed to derive the full-cycle mobility for general (serial, parallel or interconnected) manipulators. The kinematics, workspace, singularity and stiffness of the proposed manipulator are studied. The results show that the proposed manipulator outperforms the known translational decoupled Pantopteron manipulator regarding the workspace to size ratio. The proposed manipulator can also achieve configuration-independent and near-isotropic behaviors. (C) 2017 Elsevier Ltd. All rights reserved.

Route bundling implies compounding multiple routes in a way that anchoring points at intermediate locations minimize a global distance metric to obtain a tree-like structure where the roots of the tree (anchoring points) serve as coordinating locus for the joint transport of information, goods and people. Route bundling is a relevant conceptual construct in a number of path-planning scenarios where the resources and means of transport are scarce/expensive, or where the environments are inherently hard to navigate due to limited space. In this paper we propose a method for searching optimal route bundles based on a self-adaptive class of Differential Evolution using a convex representation. Rigorous computational experiments in scenarios with and without convex obstacles show the feasibility and efficiency of our approach.

Path bundling, a class of path planning problem, consists of compounding multiple routes to minimize a global distance metric. Naturally, a tree-like structure is obtained as a result wherein roots play the role of coordinating the joint transport of information, goods, and people. In this paper we tackle the path bundling problem in bipartite networks by using gradient-free optimization and a convex representation. Then, by using 7,500 computational experiments in diverse scenarios with and without obstacles, implying 7.5 billion shortest path computations, show the feasibility and efficiency of the mesh adaptive search.

© 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.Recently, large space structures are being developed. From the point of view of payload capacity and transportation efficiency, large space structures are required to be lightweight and highly efficient in their folding. Cable-panel structures are also expected to satisfy the above conditions mainly due to the omission of frames that hold panels structures. However, the deployment of three-dimensional membranes is difficult to control accurately because of the small stiffness normal to membranes. In this study, we discuss the wire location design in the wire-based deployment of three-dimensional plates. And, through experiments, we evaluate 27 design locations of wires for deployment and compare the deployed shape between the designed dimensions and the measured surface. Then, we confirmed the increment of 2.2 percent in height dimension. Furthermore, we confirmed that our proposed deployment method is feasible, and obtained several design criteria for wire design: First, it is necessary to consider an order of deployment to deploy from the outside surface. Second, the design needs to intersect folds at right angles. Third, extending the length of designs without changing the route shape of the designs leads to higher accuracy of the deployment shape without causing a large increase in the required forces. The multi particle system model was applied to predict the deformation of the structure reasonablly.

The small sattelites become popular due to the development of electrical parts and frequent launch opportunities. In this sudy, we will introduce one of our missions on orbit by 1U size small satellite Waseda-SAT3. This satellite have two main missions. One is thermal active control by soft matter and the other is measurement of shpe of membrane expanded from spiral folded shape supported by hinge-less mast. The membrane installed in this satellite has parabolic surface and painted innerside to measure shape by lattice projection method and equips solor cell outside to show effectiveness of spiral folding theory considering thickness effect of the membrane.

Directed graphs encode meaningful dependencies among objects ubiquitously. This paper introduces new and simple representations for labeled directed graphs with the properties of being succinct (space is information-theoretically optimal); in which we avoid exploiting a-priori knowledge on digraph regularity such as triangularity, separability, planarity, symmetry and sparsity. Our results have direct implications to model directed graphs by using single integer numbers effectively, which is significant to enable canonical (generation of graph instances is unique) and efficient (coding and decoding take polynomial time) encodings for learning and optimization algorithms. To the best of our knowledge, the proposed representations are the first known in the literature.

This paper presents a novel evaluation method for designing an intuitive surgical robot by measuring a user's brain activity. Conventionally, surgical robots have been designed based on their mechanical performance. However, an improvement in a robot's mechanical performance does not necessarily represent the embodiment that the user feels. In this paper, we evaluate intuitive operability based on the user's brain activation. Previously, we used functional near-infrared spectroscopictopography (fNIRS) brain imaging; however, it is better to use a brain measurement technique possessing a high time resolution, as brain activity is has a higher time resolution than fNIRS. The objective was to measure changes in brain activity as a function of a change in the slave arm positioning. In the experiment, the brain activity of four participants was measured using fNIRS while they used a hand controller to move the virtual arm of a surgical simulator. The experiment was carried out with the virtual arm in two positions: one easy to control and the other difficult. The spectrum of the brain activity increased at the easy position more than at the difficult position. We conclude that the brain activity changed as the user perceived that the virtual arm belonged to their body.

<p>This paper presents a novel evaluation method for an intuitive operability of master-slave surgical robot. Surgical robot is controlled to match the posture of the arm tip between master-slave, however, it's impossible to match the posture because strict sensing is difficult and the error accumulates during manipulation. The objective is to validate the change of the brain activation against the change of error of posture in the arm tip. In experiment, participants controlled the virtual master-slave simulation. As a result, the brain activity decreased when the error of posture in the arm tip increased. The paper concluded that the 30° would be the acceptable error because when the error was smaller than 30° , the brain activated same as he relaxed.</p>

Directed graphs are useful to encode oriented dependencies among entities. We propose a new method that enables the representation of directed graphs via numbers; enabling the succinct, canonical and efficient encoding schemes. We present examples in graph encoding and its applicability to real world networks.

© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.Authors suggested a new structure combined with lightweight membranes and booms using convex tape considering its application as a space structure.. The larger membrane is preferred to get a solar effect from sails and power generation needs. In the past researches, we assumed a square shaped flat structure and studied the use of cables, positions of cables connecting between boom and membrane. In this paper, an additional studies about a steric membrane structure with booms and cables has been carried out to confirm a structural properties. We manufactured experiment model for verifying these properties, and also we confirmed about the same kinds of properties of hexagonal structure.

Being a significant construct in a wide range of combinatorial problems, the k-subset sum problem (k-SSP) computes k-element subsets, out of an n-element set, satisfying a user-defined aggregation value. In this paper, we formulate the k-subset sum problem as a search (optimization) problem over the space of integers associated with combination elements. And by using rigorous computational experiments using the search space over more than 10(14) integer numbers, we show that our approach is effective and efficient: it is feasible to find any combination with a user-defined sum within 10(4) function evaluations by using a gradient-free optimization algorithm. Our scheme opens the door to further advance the understanding of combinatorial problems by improved/tailored gradient-free optimization algorithms based on enumerative encoding. Also, our approach realizes the practical building block for combinatorial problems in planning and operations research using k-SSP concepts.

Designing optimal ZigBee networks is key for efficient low-cost communication of multi-agent sensors and mechatronics systems. In this paper, we report a novel approach to optimize ZigBee networks using the optimization of bundled routes. To the best of our knowledge, this is the first approach reported in the literature to find optimal ZigBee network topologies.

This article aims to propose a methodology to produce an optimum design of wind turbine drivetrain with the main objectives of minimum vibration, minimum weight and maximum efficiency.

Developing affordable and robust human-machine interfaces is key to improve the quality of life of handicapped and amputee users in developing countries. While most of the available technologies are robust, the cost is inaccessible to large portions of the population with low-income. In this paper, we propose a compact, robust and cost-effective interface for arm pose sensing and control of external devices based on the low-cost accelerometer, gyroscope and Xbee technologies. Experiments using a prototype showed the promising results to detect and classify the robust poses.

In this research, we proposed a criteria development process treating about 23000 vehicle data which were published on the market from 1982 to 2013 years by Data Envelopment Analysis. DEA is the method for obtaining an evaluation with multidimensional index. However, it is necessary to determine the evaluation model. So we constructed it by Interpretive Structural Modeling. ISM builds a hierarchical structure from paired comparison, and clarifies the relationship between items. As a result, we derived 32 evaluation models from ISM and decided the best model based on the standard deviation to be maximized. This makes it possible to avoid the arbitrariness of the user. In the best model, vehicle data which have lower fuel efficiency obtain higher comprehensive evaluation value. Otherwise, in displacement and price, minimum comprehensive evaluation value is in the middle, vehicle data which has lower and higher evaluation item value obtain higher comprehensive evaluation value. In addition, we optimized the value of each evaluation item for vehicle type and obtained proposition for design for each type, which proposed smaller displacement and shape. From the above, we confirm that DEA is useful for evaluating products and ISM is efficiency for constructing the evaluation model of DEA.

PURPOSE: Accurate, noninvasive methods are sought for breast tumor detection and diagnosis. In particular, a need for noninvasive techniques that measure both the nonlinear elastic and viscoelastic properties of breast tissue has been identified. For diagnostic purposes, it is important to select a nonlinear viscoelastic model with a small number of parameters that highly correlate with histological structure. However, the combination of conventional viscoelastic models with nonlinear elastic models requires a large number of parameters. A nonlinear viscoelastic model of breast tissue based on a simple equation with few parameters was developed and tested. METHODS: The nonlinear viscoelastic properties of soft tissues in porcine breast were measured experimentally using fresh ex vivo samples. Robotic palpation was used for measurements employed in a finite element model. These measurements were used to calculate nonlinear viscoelastic parameters for fat, fibroglandular breast parenchyma and muscle. The ability of these parameters to distinguish the tissue types was evaluated in a two-step statistical analysis that included Holm's pairwise [Formula: see text] test. The discrimination error rate of a set of parameters was evaluated by the Mahalanobis distance. RESULTS: Ex vivo testing in porcine breast revealed significant differences in the nonlinear viscoelastic parameters among combinations of three tissue types. The discrimination error rate was low among all tested combinations of three tissue types. CONCLUSION: Although tissue discrimination was not achieved using only a single nonlinear viscoelastic parameter, a set of four nonlinear viscoelastic parameters were able to reliably and accurately discriminate fat, breast fibroglandular tissue and muscle.

This paper discusses and suggests a basic structure of a mixed constitute of lightweight membranes and booms by looking slightly future of space structure which will become larger and larger to be tens of meter class such like future deep space exploration by solar sails or self-power generation by thin solar films etc⋯Or in short-sighted developing vision, this type of structure is going to be applied to the deorbit hardware for low-orbit satellites to earn much drag for atmosphere entry within smaller years. All of such application need that the structure should have a certain stiffness, so our interest is how to design to get efficient stiffness improvement and also we should be care not to ruin other structural merit such like small wrinkle amount. First, we focused on adding extension force in axial direction of each boom and studied where to put. Then the efficiency of cable connection on the oblique line of a membrane is also verified. After integrated these design factors, we focused on the actual construction phase that may be difficult to realize completely flat surface especially in tens of meters class structure, so we assumed that the manufactured structure will be steric, and we focused on finding the steric stabilized structure by using boom and cables as supportive members. Relation between 1st eigen frequency which is the bending mode of a boom is mainly studied and it becomes obvious that the steric structure improves it more efficiently than other design factor. These examinations are not only carried out on square model, but also on hexagonal model which is also versatile geometry for expanding module structure in the future, and this shows that the optimum boom angle exists to make wrinkle amount becomes minimum. This can be a designing guidepost for future use of boom-membrane structure. Then we consider all the design factor at once and suggest the three dimensional basic structural design for large light weight space structure.

The search for novel and high-performing product designs is a ubiquitous problem in science and engineering: aided by advances in optimization methods the conventional approaches usually optimize a (multi) objective function using simulations followed by experiments. However, in some scenarios such as vehicle layout design, simulations and experiments are restrictive, inaccurate and expensive. In this paper, we propose an alternative approach to search for novel and high-performing product designs by optimizing not only a proposed novelty metric, but also a performance function learned from historical data. Computational experiments using more than twenty thousand vehicle models over the last thirty years shows the usefulness and promising results for a wider set of design engineering problems.

Recently, radio frequency ablation (RFA) has become one of the most popular thermal treatments for liver cancer. RFA is minimally invasive and effective in inducing tumor coagulation, however, because use the procedure depends on the experience of the physician, consistent accuracy cannot be guaranteed. In particular, when the tumor is close to a large vessel, a suboptimal ablation margin can result in tumor recurrence. To improve the accuracy of RFA treatment, we have developed an RFA supporting system, which was constructed by using finite element method and operated by means of a model-based control method. In this study, we focused on the cooling effect of flow volume inside a large vessel during RFA, and analyzed heat transfer between the large vessel and liver tissue using a model. We derived the heat transfer parameter (the Nusselt number (Nu)) between the large vessel and liver tissue during RFA by using a finite-element method (FEM). When the Nu for FEM analysis had a value of 3, the FEM analysis model was representative of the actual ablation objective, and the maximum error between FEM analysis and the measurement results was within 2.0[degrees C]. Thus, it was suggested that the Nu was effective for FEM analysis regarding heat transfer between a large vessel and tissue. However, according to the differences between the results of FEM analysis and measurements concerning the three livers, the heat transfer volume was determined by the Nu, which is different individually in common with other thermal properties. In conclusion, it is necessary to consider the individual differences in the heat transfer volume parameter for FEM analysis.

Radio Frequency Ablation (RFA) is one kinds of hyperthermia treatment for cancer. Advantages of RFA are mainly low impact operations and shorter hospital stay. Disadvantage of RFA is difficult to get coagulation information for operator. Therefore, it needs to control ablation energy precisely. Thus, we have been proposed a method control of ablation energy. A feature of RFA, it uses electromagnetic-wave for ablation. RFA is related as not only thermal physics but also electrical physics. And, Heat generation from RF-electrode depends on frequency of electromagnetic-wave frequency. Therefore, in this study, we modeled heat generation based on electric impedance frequency characteristic during RFA. Firstly, it measured electric impedance frequency characteristic of pig liver samples. Secondly, it measured temperature distribution of the samples during RFA. Finally, it modeled electric impedance frequency characteristic of pig liver samples based on equivalent circuit model which was considered about fractional calculus. And, we evaluated a value of electrical impedance. From results, Model value of heat generation was matched with actual measurement value by using a coefficient of electrical impedance.

© 2015 Taylor & Francis Group, London. Printed Circuit Boards (PCBs) are important for operation of actuators to work machines and required upgrading and downsizing. To develop upgrading PCBs needs design based on evaluation criteria. In this study, we verified the availability of GA in pattern design of PCBs by use of the electric power board on WASEDA-SAT2 (small satellite) as a model. As a result, the smaller board by 35% was obtained than the board before optimization.

Recently, Radio Frequency Ablation (RFA) is becoming a popular therapy for various cancers such as liver, breast, or lung cancer. RFA is one kinds of thermal therapy. However, it has been often reported about excessive ablation or non-ablation due to difficult control of ablation energy. In order to solve these difficulties, we have been proposed robotized RF-ablation system for precise cancer treatment. We have been tried to control heat energy by control of electromagnetic-wave frequency.
In this paper, we reported about relation among electrical impedance of lung, lung's internal air volumes, and heat energy by use of electromagnetic- wave. In case of RFA for lung cancer, heat energy depends on electrical impedance and lung's internal air volumes. Electrical impedance has the dependence of electromagnetic-wave frequency and the dependence of lung's internal air volumes. Therefore, firstly we considered about fractional calculus model between lung's internal air volumes and electrical impedance. Secondly, we measured electric impedance frequency characteristic of lung with change of lung's internal air volumes. The measured and modeled results showed that use of fractional calculus realized high accurate model for electrical impedance of lung. And, from the results of numerical analysis of heat energy, it is supposed that control of electromagnetic-wave frequency has a small effectiveness for lung tissue ablation even if lung includes abundant air.

Design optimisation technologies are a practical requirement when aiming to obtain optimal product design variable values from an initially given feasible design space, but such technologies also can contribute to the generation of more effective product design alternatives, namely, product design innovations. This paper proposes an effective evaluation method that enables improvement of product design ideas, using characteristic-based hierarchical optimisation strategies applicable to industrial machine products. After related characteristics are decomposed into simpler characteristics, or simpler characteristics are extracted from higher level characteristics, new optimisation strategies are constructed based on clarification of the relationships among all the characteristics. Innovative processes that lead to product design improvements are analysed in detail by examining optimum solutions for various design improvement ideas, using displays of Pareto optimum solution lines or surfaces. The proposed system design optimisation method that is based on evaluations of evolutional Pareto optimum solutions is presented and exemplified here using an articulated robot product design, and applied at the conceptual product design stage.

Scaled dummy used in the experiment on the estimation of passenger's behavior under a train collision is designed considering a similarity rule. Several tests are applied to evaluate dummy biofidelity according to ISO technicalreport ISO/TR9790. Overall biofidelity of the dummy is 4.62 points out of 10. And it is the third-highest rating "Fair Biofidelity" out of 5 ratings indicating the degree of biofidelity. Next, Finite element is applied conducted to improve thoraxbiofidelity dummy using optimization method, suchas breadth of rib, thickness of soft tissue and Elastic Modulus of soft tissue because response on thoraximpact test is particularly bad. Optimized dummy is developed and thoraximpact test is conducted again. The maximum value of impactor force of optimized dummy is 28.1% better than that of unoptimized one.

In the stage of a conceptual design, designers often stimulate and influence each other, and they must conceive a completely new idea and the outstanding idea. However, as a design problem, it is dependent on a designer's experience and intuition. Furthermore, the suggestion of an idea is sometimes plentifully performed by two or more persons, sharing of mutual knowledge or information for a smooth communication. Therefore, it is necessary to establish the reasonable design method to derive excellent idea, in this study, the new design approach which combined two design methods of an axiomatic design theory and TRIZ is proposed, the validity of a design method is confirmed. The axiomatic design theory clarifies the process in a design TRIZ offers the solution of a design which a designer didn't know. By combining these advantages, we will proposed a new method. The experiment using the proposed methods, technique nothing, TRIZ, the axiomatic design theory, and the TRIZ+ axiomatic design theory. And, it is verified what kind of difference the number of ideas or quality. As a result, TRIZ was able to conceive many ideas, but quality is inferior to other design methods. The axiomatic design theory could conceive the high quality idea, but a number of ideas are inferior to other design methods. Although the TRIZ+ axiomatic design theory had few ideas, the highest quality idea was able to be conceived.

In this study, we try to design a shock absorbing structure using the compliant mechanism. To design the shock absorbing structure, it is necessary to consider the plastic deformation. We use the elastic-plastic body to design the compliant mechanism. First, we do topology optimization whose object function is to design the shock absorbing structure and the compliant mechanism. In this topology optimization, we use Evolutionary Structual Optimization. And we investigate the shape and the characteristic while the parameters fluctuation. Secondly, the impact test is done to confirm whether it is functioning as a shock absorbing structure. We test two models and compare the behavior of each model.

Radio frequency ablation (RFA) is one of the minimally invasive and useful treatments for liver cancer. While RFA is popular approach for liver cancer in Japan, RFA has several disadvantages such as ablation temperature is excess or insufficient. Because flow in great vessels absorbs the heat from electrode needle in liver RFA, it is difficult for surgeon to estimate the temperature distribution. In this study, we used the experimental system with porcine great vessels and porcine liver to investigate about the relationship between heat loss and flow volume in great vessels. We calculated the heat transfer coefficient based on Newton's law of cooling under each flow volume in each great vessel, and figured out the relationship between heat transfer coefficient and flow volume. As a result, heat transfer coefficient depends on flow volume in great vessels. And the relationship between heat transfer coefficient and flow volume is linearity. These results suggested that the relationship between flow volume in blood vessel and heat transfer coefficient is linearity, and flow volume in blood vessel causes heat loss in RFA.

We propose a product design optimization method that maximizes the integrated satisfaction level for evaluative factors. Product designs include many evaluative factors that have complex interrelationships. To cope with such circumstances, we construct strategies and a practical method to obtain optimum design solutions. First, the evaluative items for the product are listed and each item is decomposed into evaluative factors. Next, to express designers' or potential customers' levels of satisfaction for the characteristic values of each evaluative factor, we define satisfaction functions that incorporate the relationship between characteristic values and satisfaction levels. Weighting coefficients for the evaluative factors are then obtained by the pair comparison method. Finally, an integrated satisfaction level is formulated by summing the characteristic values with their weighting coefficients over the entire set of evaluative factors. The integrated satisfaction level of the objective function is maximized, and optimum design solutions with maximum satisfaction levels are then obtained. If necessary, these solutions can be modified and improved by re-examining and adjusting the satisfaction functions and weighting coefficients. Furthermore, the proposed method can be used to find schemes that improve the integrated satisfaction level. The utility of the proposed method is demonstrated using a passenger train coach design.

Recently radio frequency ablation (RFA) has been increasingly important in treating liver cancers. RFA is ordinarily conducted using elastographic imaging to monitor the ablation procedure and the temperature of the electrode needle is displayed on the radiofrequency generator. However, the coagulation boundary of liver tissue in RFA is unclear and unconfident. This can lead to both excessive and insufficient RFA thereby diminishing the advantages of the procedure. In the present study, we developed a method for determining the coagulation boundary of liver tissue in liver RFA. To investigate this boundary we used the mechanical characteristics of biochemical components as an indicator of coagulation to produce a relational model for viscoelasticity and temperature. This paper presents the data acquisition procedures for the viscoelasticity characteristics and the results of relationship model of viscoelasticity's temperature dependence. We employed a rheometer to measure the viscoelastic characteristics of porcine liver tissue. To determine relationship model between temperature and viscoelasticity, we used a least-square method and the minimum root mean square error was calculated to optimize the model functional relations. The functional relation between temperature and viscoelasticity was divided into linear and non-linear in different temperature regions. The boundary between linear and non-linear functional relation was 58.0°C. © 2013 The Japan Society of Mechanical Engineers.

Radiofrequency (RF) ablation is increasingly being used to treat liver cancer because it is minimally invasive. However, it is difficult for operators to control the size of the coagulation zones precisely, because no method has been established to form an adequate and suitable ablation area. To overcome this limitation, we propose a new system that can control the coagulation zone size. The system operates as follows: 1) the liver temperature is estimated using a temperature-distribution simulator to reduce invasiveness
2) the output power of the RF generator is controlled automatically according to the liver temperature. To use this system in real time, both the time taken to calculate the temperature in the simulation and the control accuracy are important. We therefore investigated the relationship between the time interval required to change the output voltage and temperature control stability in RF ablation. The results revealed that the proposed method can control the temperature at a point away from the electrode needle to obtain the desired ablation size. It was also shown to be necessary to reduce the time interval when small tumors are cauterized to avoid excessive treatment. In contrast, such high frequency feedback control is not required when large tumors are cauterized. © 2013 IEEE.

Radio frequency ablation (RFA) for lung cancer has increasingly been used over the past few years because it is a minimally invasive treatment. As a feature of RFA for lung cancer, lung contains air during operation. Air is low thermal and electrical conductivity. Therefore, RFA for this cancer has the advantage that only the cancer is coagulated, and it is difficult for operators to control the precise formation of coagulation lesion. In order to overcome this limitation, we previously proposed a model-based robotic ablation system using finite element method. Creating an accurate thermo physical model and constructing thermal control method were a challenging problem because the thermal properties of the organ are complex. In this study, we measured electromagnetic wave frequency dependence of lung's electrical conductivity that was based on lung's internal air volumes dependence with in vitro experiment. In addition, we validated the electromagnetic wave frequency dependence of lung's electrical conductivity using temperature distribution simulator. From the results of this study, it is confirmed that the electromagnetic wave frequency dependence of lung's electrical conductivity effects on heat generation of RFA.

We describe a robotic palpation system that determines whether a breast tumor is benign or malignant by measuring its nonlinear elasticity. Two indenters compress the breast from different directions to generate sufficient strain on the inner tumor, which simply represents clinical dynamic testing. The nonlinear elasticity of the inner tumor is estimated by correcting the reaction force data of the surrounding soft tissue. Here, we present the basic concept of our study and simulation results considering geometric conditions of the indenters using a finite element breast model. Indenters with variable width are applied to the breast at several contact positions in a simulation for comparison. Our results indicate that when the spring stiffness between the contact position of one indenter and the center of the tumor equals the spring stiffness between the contact position of the other indenter and the center of the tumor, a larger contact area (i.e., larger spring stiffness) provides larger strain acting on the inner tumor. © 2013 IEEE.

Radio frequency ablation (RFA) is usually conducted using ultrasound (US) imaging to monitor the insertion procedure and the coagulation extent of liver tissue which is contiguous to the RFA electrode. However, when RFA surgery is started, the US image becomes unclear because of water vapor. This disadvantage of RFA can lead to excessive and insufficient RFA thereby diminishing the advantages of the procedure. In the present study, we proposed a simulation system which shows the progress status of coagulation for liver RFA. To derive the coagulation characteristics in liver RFA, we used the viscoelasticity of liver tissue as the coagulation indicator to investigate coagulation development for liver RFA. This paper shows the acquisition procedures for analyzing the relationship between the rate of temperature and viscoelasticity. We measured the complex modulus of porcine liver tissue under different rate of temperature in RFA by controlling the output power. We showed that the viscoelasticity of liver tissue depended on temperature previous temperature increase above 60°C. This result indicates that in RFA, controlling the output power is important to completely coagulate the tumor. © 2013 IEEE.

Recently radio frequency ablation (RFA) has been increasingly important in treating liver cancers. RFA is ordinarily conducted using elastographic imaging to monitor the ablation procedure and the temperature of the electrode needle is displayed on the radiofrequency generator. However, the coagulation boundary of liver tissue in RFA is unclear and unconfident. This can lead to both excessive and insufficient RFA thereby diminishing the advantages of the procedure. In the present study, we developed a method for determining the coagulation boundary of liver tissue in liver RFA. To investigate this boundary we used the mechanical characteristics of biochemical components as an indicator of coagulation to produce a relational model for viscoelasticity and temperature. This paper presents the data acquisition procedures for the viscoelasticity characteristics and the results of relationship model of viscoelasticity's temperature dependence. We employed a rheometer to measure the viscoelastic characteristics of porcine liver tissue. To determine relationship model between temperature and viscoelasticity, we used a least-square method and the minimum root mean square error was calculated to optimize the model functional relations. The functional relation between temperature and viscoelasticity was divided into linear and non-linear in different temperature regions. The boundary between linear and non-linear functional relation was 58.0°C. © 2013 The Japan Society of Mechanical Engineers.

A disadvantage of nonlinear elastography techniques for breast tumor diagnosis is that the tumor does not strain sufficiently to observe nonlinear elasticity We propose a robotic palpation system with two indenters to evaluate the nonlinear elasticity properties of tissues The objective of the present study was to consider a compression method in terms of the position of indenters and the section area of indenters to generate large strain in tumors by finite element analysis As a result, it was found that the following compression conditions made tumor deformable First condition is that the default position of indenter is located near the tumor Second condition is that the section area of indenters is enlarged if the default position of indenter is located near the tumor, and the section area of indenters is made smaller if the default position of indenter is distance from the tumor

When major train collisions occur, train structure deforms to reduce the impact effect. However, some passengers are injured in spite of the shock absorption of the structure. Therefore, it is necessary to design train structure to reduce injuries of passengers when accidents occur. In this study, we proposed the design improvements strategies to reduce injuries of the passengers caused by train collisions. We experimented with scale-down models of passengers and vehicles. To evaluate injury levels, we used HIC36 as a standard for head injuries. As a result of these experiments, HIC36 is influenced by seating position and type. We proposed three train structures to reduce injuries of passengers. These are that of using convertible seats, seating passengers with their backs to the front of the train and seating passengers in the rear of the vehicle.

In this study, to design a shock absorbing structure using the compliant mechanism. To be applied to the shock absorbing structure is necessary to consider the plastic deformation. However, in previous studies such research has not been done. In the present study to design a compliant mechanism targets the elasto-plastic body. And this mechanism is applied to impact-absorbing structure. First we use topology optimization whose object function is to design shock absorbing structure and compliant mechanism. And we can design model which has compliant mechanism and shock absorbing function. Secondly impact test is performed using this mechanism. We create a model for comparison for this test. We compare the behavior of each model and discuss about it.

Recently the development of the nano satellite becomes active. In general, nano satellites are expected to be developed faster and cheaper than the large satellites. The launching cost of the piggyback satellite is reasonable, and then a cost of a piggyback satellite is often decided by weight. Therefore it is important to reduce the weight of satellite for cost. We have to design of satellite structure considering the severe mechanical environment of launching. The natural frequency of the satellite should be higher than the value decided by the rocket and the satellite should withstand the loads during launch. In addition, harnesses are also important component when we design satellites. In this paper, we will propose the design of the satellite whose dimension is 400 millimeters cube. The satellite supposed to be launched by H-2A rocket and we focused on the trade-off design between minimization of mass and maximization of natural frequency under the maximum stress condition for optimizing the satellite structures.

RFA is a treatment modality for cancer that is becoming accepted because of its less-invasiveness and high-curability. Controlling the shape of ablation area increases curative effect. Therefore we propose the mechanism of electrode needle that RF current flow between two secondary electrode needles. We examined the parameters required to obtain a trapezoidal ablation area surrounded by two electrode needles. The result of simulation, it was suggested that the relation of length and thickness of two needles affect ablation. In addition, we performed ablation experiments using agar phantoms. We evaluated the ablation shape of simulation and experiment as three-dimensional cube set. Then, we confirmed that result of simulation and experiments were in agreement.

This paper addresses a diagnostic palpation system based on the measurement of nonlinear elasticity. An indentation probe is used to press against breast tissue. Then, the measured reaction force is used to estimate the parameters of nonlinear elasticity, which enables the identification of tissue type, such as fat, muscle, mammary gland or tumor. Here, we present the basic concept of our study and preliminary experimental and simulation results from pilot studies. More specifically, we measured the nonlinear response of reaction force using the breast of a goat. In addition, we also simulated the reaction force using nonlinear biomechanical simulation with several tissue types. Large differences in reaction force occur only in the nonlinear range in both experimental and simulation situations. Our results confirmed the feasibility of our concept.

Radiofrequency (RF) ablation is increasingly used to treat cancer because it is minimally invasive. However, it is difficult for operators to control precisely the formation of coagulation zones because of the inadequacies of imaging modalities. To overcome this limitation, we previously proposed a model-based robotic ablation system that can create the required size and shape of coagulation zone based on the dimensions of the tumor. At the heart of such a robotic system is a precise temperature distribution simulator for RF ablation. In this article, we evaluated the simulation accuracy of two numerical simulation liver models, one using a constant thermal conductivity value and the other using temperature-dependent thermal conductivity values, compared with temperatures obtained using in vitro experiments. The liver model that reflected the temperature dependence of thermal conductivity did not result in a large increase of simulation accuracy compared with the temperature-independent model in the temperature range achieved during clinical RF ablation.

Radio frequency ablation (RFA) for lung cancer has increasingly been used over the past few years, because it is a minimally invasive treatment. As a feature of RFA for lung cancer, lung contains air. Air is low thermal and electrical conductivity. Therefore, RFA for this cancer has the advantage that only the cancer is coagulated, because the heated area is confined to the immediate vicinity of the heating point. However, it is difficult for operators to control the precise formation of coagulation zones due to inadequate imaging modalities. We propose a method using finite element method to analyze the temperature distribution of the organ in order to overcome the current deficiencies. Creating an accurate thermal physical model was a challenging problem because of the complexities of the thermal properties of the organ. In this study, we developed a temperature distribution simulator for lung RFA using thermal and electrical properties that were based on the lung's internal air dependence. In addition, we validated the constructed simulator in an in vitro study, and the lung's internal heat transfer during RFA was validated quantitatively.

In this paper, finite element methodology was applied to predict the deformation of tissue during lung collapse using pre-operative information. Accurate prediction of lung collapse deformation prior to surgical intervention can provide valuable diagnostic information to clinical staff, allowing a better understanding of the movement of the target segment. This paper describe the methodology to derive the deformed shape of finite element model that satisfy the equilibrium condition using 3-D model developed from the image measured by a multi-slice CT imaging device. The movement of the target segment can be predicted by the finite element model. Previous research studies applied the distributed load on the surface of the lung structure as loading conditions. Here we have suggested a method that considers the deformation of alveoli contraction and elongation while breathing. Specifically, by introducing the governing equations of a reduction in volume strain into the governing equations of the finite element method, lung structure is analyzed. Lung deformation obtained from the analysis was compared with experimental results and compared with the proposed method. The proposed method showed an improvement of deformation-prediction accuracy as 0.58%. We confirmed the qualitative similarities between the deformation of the analysis and the experiment, thus demonstrating the effectiveness of the proposed method.

Recently radiofrequency (RF) ablation has become increasingly important in treating liver cancers. RF ablation is ordinarily conducted using elastographic imaging to monitor the ablation procedure and the temperature of the electrode needle is displayed on the RF generator. However, the coagulation boundary of liver tissue in RF ablation is unclear and unconfident. This can lead to both excessive and insufficient RF ablation thereby diminishing the advantages of the procedure. In the present study, we developed a method for determining the coagulation boundary of liver tissue in RF ablation. To investigate this boundary we used the mechanical characteristics of biochemical components as an indicator of coagulation to produce a relational model for viscoelasticity and temperature. This paper presents the data acquisition procedures for the viscoelasticity characteristics and the analytical method used for the coagulation model. We employed a rheometer to measure the viscoelastic characteristics of liver tissue. To determine the model functional relationship between viscoelasticity and temperature, we used a least-square method and the minimum root mean square error was calculated to optimize the model functional relations. The functional relation between temperature and viscoelasticity was linear and non-linear in different temperature regions. The boundary between linear and non-linear functional relation was 58.0 degrees C.

We propose a product design optimization method that maximizes the integrated satisfaction level for evaluative factors. Product designs include many evaluative factors that have complex interrelationships. To cope with such circumstances, we construct strategies and a practical method to obtain optimum design solutions. First, the evaluative items for the product are listed and each item is decomposed into evaluative factors. Next, to express designers' or potential customers' levels of satisfaction for the characteristic values of each evaluative factor, we define satisfaction functions that incorporate the relationship between characteristic values and satisfaction levels. Weighting coefficients for the evaluative factors are then obtained by the pair comparison method. Finally, an integrated satisfaction level is formulated by summing the characteristic values with their weighting coefficients over the entire set of evaluative factors. The integrated satisfaction level of the objective function is maximized, and optimum design solutions with maximum satisfaction levels are then obtained. If necessary, these solutions can be modified and improved by re-examining and adjusting the satisfaction functions and weighting coefficients. Furthermore, the proposed method can be used to find schemes that improve the integrated satisfaction level. The utility of the proposed method is demonstrated using a passenger train coach design.

Recently the development of the nano satellite becomes active. In general, nano satellites are expected to be developed faster and cheaper than the large satellites. The launching cost of the piggyback satellite is reasonable, and then a cost of a piggyback satellite is often decided by weight. Therefore it is important to reduce the weight of satellite for cost. We have to design of satellite structure considering the severe mechanical environment of launching. The natural frequency of the satellite should be higher than the value decided by the rocket and the satellite should withstand the loads during launch. In this paper, we will propose the design of the satellite whose dimension is 400 millimeters cube. The satellite supposed to be launched by H-II A rocket and we focused on the trade-off design between minimization of mass and maximization of natural frequency under the maximum stress condition for optimizing the satellite structures.

An experiment on the estimation of a large number of passenger's behavior in under a train collision is studied using small train model. Here, we treated the position of passenger paying attention to a seat for seven persons. As a result of the experiment, passenger's head injury is influenced by seating position or coefficient of static friction of floor material. We discussed relation of between seating position or coefficient of static friction of floor material and passenger's head injury, and proposed four ideas reducing damage of passengers.

In conceptual design phase, According paying attention to specific design objectives, designers sometimes avoid to get various ideas about new product. On the other hand, using brainstorming allows to get various ideas, but it causes a problem to obtain a lot of unavailable ideas together. In this study, to support generating various and effective ideas in conceptual design, we propose a conceptual design support method applying Data Envelopment Analysis and TRIZ. We proposed the method using several evaluation values to fill the gap of pareto frontier and creating hierarchy graphs. In this study, we propose the method using TRIZ at the Brain Storming stage in addition to the our proposed method. Various information is given to the designer from hierarchy relation graphically and TRIZ when they conceive new ideas. We verified which technique is effective to obtain new ideas with high evaluation by comparing these two methods. The result shows that the proposed method using TRIZ is more efficient than the other way not using TRIZ.

As the number of breast cancer patients increases, non- invasive and accuracy diagnosis of breast cancer is required. It is expected that there is diagnostic potential in examining the nonlinear elastic properties of soft tissues. The measurement method of the nonlinear elasticity of tumor in breast is needed. Therefore, we propose the robotic palpation system for diagnosis based the nonlinear elasticity. Here, we report the measurement of the nonlinear elastic properties of breast tissue components. The nonlinear elastic properties of breast tissue were investigated with a creep test. The three parameters of the nonlinear elastic model were acquired. In conclusion, two of these parameters are significantly different among the components. There was indicated that the magnitude of parameter is determined by tissue structure. There was suggested that the difference in parameter distribution causes the difference in dynamic response of breast tissue.

Lung cancer has become one of most killing disease in 20th century. There are various external and internal causes identified by experts to be the causes of this disease. Various type of treatments have been developed taking account on the stage and condition of cancer itself, such as Radiation Therapy, Chemotherapy and Surgery.
In this paper, a method called Thoracoscopy is focused for improvement by investigating a possibility of using finite element method (FEM) to predict deformation and movement of tumor during lung lethargy process as a preparation stage for this surgery method to be deployed. Thoracoscopy is suitable for stage-I cancer, as it will only create a small incisions on the skin and has high possibility to cure by removing the tumor. This paper used a commercial FEM tool to model lung in 3-dimension and by using tested data of material properties, a simulated result of lung lethargy process was compared with experimental data. Results revealed a few promising points to further develop this virtual capability and use it to predict deformation prior the surgery.

Radiofrequency ablation is increasingly being used for liver cancer because it is a minimally invasive treatment method. However, it is difficult for the operators to precisely control the formation of coagulation zones because of the cooling effect of capillary vessels. To overcome this limitation, we have proposed a model-based robotic ablation system using a real-time numerical simulation to analyze temperature distributions in the target organ. This robot can determine the adequate amount of electric power supplied to the organ based on real-time temperature information reflecting the cooling effect provided by the simulator. The objective of this study was to develop a method to estimate the intraoperative rate of blood flow in the target organ to determine temperature distribution. In this paper, we propose a simulation-based method to estimate the rate of blood flow. We also performed an in vitro study to validate the proposed method by estimating the rate of blood flow in a hog liver. The experimental results revealed that the proposed method can be used to estimate the rate of blood flow in an organ.

As the number of breast cancer patients increases, there is an increasing need for accurate non-invasive methods for the diagnosis of breast cancer. It is possible that the nonlinear elastic properties of soft tissues of the breast can be used as a basis for diagnostic methods. Therefore, we have proposed a robotic palpation system for diagnosis based on the nonlinear elastic properties of tissue. Here, we measured the nonlinear elastic properties of soft tissues of the breast using creep tests and three parameters of the nonlinear elastic model were acquired. Two of these parameters are significantly different among soft tissues of the breast and that the magnitude of these parameters was determined by the tissue structure. These parameters could be used to differentiate between tissue types and aid in the diagnosis of breast cancer.

This paper addresses a diagnostic palpation system based on the measurement of nonlinear elasticity. An indentation probe is used to press against breast tissue. Then, the measured reaction force is used to estimate the parameters of nonlinear elasticity, which enables the identification of tissue type, such as fat, muscle, mammary gland or tumor. Here, we present the basic concept of our study and preliminary experimental and simulation results from pilot studies. More specifically, we measured the nonlinear response of reaction force using the breast of a goat. In addition, we also simulated the reaction force using nonlinear biomechanical simulation with several tissue types. Large differences in reaction force occur only in the nonlinear range in both experimental and simulation situations. Our results confirmed the feasibility of our concept.

Radio frequency ablation (RFA) for lung cancer has increasingly been used over the past few years because RFA is minimally invasive treatment for patients. As a feature of RFA for the lung cancer, lung has the air having low thermal conductivity. Therefore, RFA for lung has the advantage that only the tumor is coagulated because heating area is confined to the immediate vicinity of the heating point. However, it is difficult for operators to control the precise formation of coagulation zones due to inadequate imaging modalities. We propose a method using numerical simulation to analyze the temperature distribution of the organ in order to overcome the current deficiencies. Creating an accurate thermophysical model was a challenging problem because of the complexities of the thermophysical properties of the organ. In this work, as the processes in the development of ablation simulator, measurement of the pressure dependence of lung thermal conductivity and in vitro estimation of the temperature distribution during RFA is presented.

This paper presents a new identification method for the biomechanical parameters of human tissues for the purpose of improving the accuracy of dynamic organ simulation. We describe the formulation of the method, and also design a robotic system to implement the method using a robotic probe, a medical imaging device, and a numerical simulator for the finite element analysis (FEA). We carried out an experiment using an experimental system and a tissue phantom to verify the effectiveness of the method. The results of this experiment show that the Young's modulus of the tissue phantom can be estimated with the experimental system. We also compared the estimated values of the Young's moduli with the measured values from a rheometer. These results confirm that the identification method and the system design, proposed and developed in this work, are effective for accurately simulating organ behavior.

The corrugated cardboard is widely used for packing in the transportation. Therefore, the technology that minimizes various transportation accidents is necessary. Especially, the accidents by the impact occupies the more than the half of the accidents. There are many researches that evaluates the maximal acceleration of the corrugated cardboard under the impact. However, because the maximal acceleration is not necessarily corresponding to the damage of contents, it is difficult to evaluate the impact of the corrugated cardboard only by the maximal acceleration. Also the place to measure is the center of the ground side but it is not discussed about the measuring place. In this paper, impact force is applied by a free fall test by a guide rail to drop it straight to the ground. The ID acceleration sensor, are glued in several place to make clear the difference between the measured place. From the experiment, we considered impact energy and the maximal acceleration. In addition, we made an analytical model of the corrugated cardboard to analysis to identity the damage. As a result, strain energy has a correspondence between the experiment and the analysis and the maximal acceleration didn't have it. So, the utility of the strain energy was able to be shown as a method of evaluating the impact using FEM. Through this result, we watched how the energy spread and found out the center of the ground side and the wall side has a high energy when it's impacted and when a few second pasts the wall side still has a high energy because of the vibration of the cardboard. To find out the relation between the data from the corrugated cardboard and the contents. As a result, the maximal acceleration has a strong relation between the center of the ground side and the energy has a strong relation between the middle of the center and the corner. Finally, we also considered HIC36 to evaluate the impact.

In conceptual design phase, if designers are much more conscious of design objectives, they won't come up with various ideas about new product. On the other hand, using brainstorming allow to get various ideas, but to get a lot of unavailable ideas together. In this study, to support generating various and effective ideas in conceptual design, we propose two conceptual design support methods based on Data Envelopment Analysis and Analytic Hierarchy Process. The former is the method using several evaluation values to fill the gap of palate frontier and creating hierarchy graphs. The latter is method establishing a prioritized list of all ideas by paired comparison. Various information is given to the designer from these graphs when they conceive new ideas. We verified which technique is effective to obtain new ideas with high evaluation by comparing these two methods. The result shows that the proposed method using hierarchy graphs is more efficient than the other way using the prioritization graph.

It is required to collapse a lung in VATS (video-assisted thoracic surgery). The tumor position is displaced corresponding to ling collapse. Then, navigation system, which presents the tumor position for a surgeon without any palpation process, may be effective for VATS. The purpose of this study is to develop the navigation system using the collapse simulation of lung. This paper shows a collapse simulation with a loaf lung, which has no lobatum, as a first step of this study. First, we obtained and modeled the material properties of hog lung from the data obtained by rheometer. The Zener's model was used to represent the viscoelastic properties of lung from the analysis of the data. Next, the biomechanical model of lung was developed based on Finite Element Method. The collapse simulation was carried out using the model. The analysis result shows the lung model was collapsing and the deformation had the similar tendency to real lung.

Radiofrequency ablation (RFA) for liver cancer has increasingly been used over the past few years because RFA is minimally invasive treatment for patients. However, precise control of the formation of coagulation zones is difficult for operators due to inadequate imaging modalities. With this in mind, we have proposed a model-based robotic ablation system using numerical simulation to analyze temperature distributions in the organ to overcome this deficiency. The objective of our work is to develop a temperature-dependent thermophysical organ model to construct a precise numerical simulator for RFA. However, no standard methods exist for obtaining the thermophysical properties of biological tissues, as detailed evaluations of the accuracy of properties obtained from various experiments have not been completed. The purpose of this study was thus to measure and model the temperature dependence of thermal conductivity in hog liver from three representative methods, and to compare these results using our developed numerical simulator to reveal differences in temperature distributions stemming from differences in thermal conductivities.

In this paper we present a new robotic palpation method to perform quantitative measurement of the material parameters of human tissues, for use in medical applications. The proposed method is achieved by the use of a system that integrates a robotic component and a numerical simulation component. The robotic component is used to measure the contact force and displacement at each point on the human body contacted by a robotic probe. The numerical simulation component identifies the material parameters using the proposed method, where two data sources are used, namely, (1) the measured data from the robotic part, and (2) simulated deformation data obtained by the finite element method. In order to validate the proposed system, we report initial results from several phantom tissue experiments, which demonstrate the ability of the system to quantitatively determine the elastic moduli of tissues. We also discuss several potential challenges in the future of the proposed system.

As compared with automobile, few train design methods for crashworthiness have been proposed. To establish it, we paid attention to double structure composed of train exterior and cabin, and designed train finite element model. We changed the position and thickness of steel plates joining these two constituents, and simulated train collision to a rigid body wall at the speed of 60 kilometer per hour. As a result of the optimization, it was shown that distortional energy in the cabin and maximum deceleration were reduced. We discussed relation of between absorbed energy and maximum deceleration, and introduced new train structure.

Recently the development of the small satellite becomes active. In general, small satellites are expected to be developed faster and cheaper than the large satellites. A cost of a piggyback satellite is often decided by weight. Therefore it is important to reduce the weight of satellite for cost. Considering the severe mechanical environment of launching, we have to design satellite structure. The natural frequency of the satellite should be higher than the value decided by the launching and the satellite should bear the loads during launch. And the satellite should be considered with the value of the moment of inertia and a center of gravity because of stability of position. In this paper, we will propose the design of the satellite whose dimension is 20 centimeters cube. We focused on the trade-off design between minimization of stress condition and the appropriate center of gravity and the moment of inertia under the minimum natural frequency and the maximum mass for optimizing the satellite structures.

This study treats human body model and cellular automata for analysis of the passenger behavior for the deceleration at the time of the railway accident. At this case, the deceleration obtained from simulation of the railroad carriage model is used for simulation suppose to collision to the rigid body wall. Consequently, it was shown that injury to the passenger was able to be reduced by the parameter of the partition and the floor when accident was occured.

The designers often are required to derive ideas of the products satisfying requirements of users and market. To accomplish to derive good design, it is important to have much information for previous designs and collaborate with the other designers. At an early stage of design process, several designers have to derive ideas considering its evaluation in cooperation. In this stage, some existing methods to support thinking processes among several persons are useful. However, it is difficult to give a direction for discussion because a reasonable evaluation of ideas is difficult and it is also difficult for the evaluation to be accepted by the other designers. In this study, we propose a method to support generating various and effective ideas in conceptual design process. The ideas are mathematically defined to have factors of evaluation and features and numerically treated in these factors space. Data Envelopment Analysis (DEA) is applied for ideas having many factors of evaluation to derive reasonably a scalar value for evaluation result. DEA gives us a segment of many ideas and from this segment we can discuss a new idea. To support deriving a new idea, we have identified nonlinear mathematical model between factors of evaluation and features and optimization method was applied for the identified model. The proposed method is applied for the experiment and we could confirm the effectiveness of the proposed method.

At an early stage of design process, it is required to discuss many ideas derived from design requirements using designer's knowledge and experiences. Especially, at conceptual design stage, many designers often discuss together about new product and discuss design ideas considering its effectiveness. However, according to increasing the complexity of the functions of products and variety of consumer's needs in recent years, it becomes difficult for designers to discuss about ideas by only conversations and figures. Then, in the conceptual design process, it is required to derive many ideas that meet the design requirement considering the complicated requirements. The derivation process of ideas often wastes the time because of the inertia of designer's thinking process. In this study, we will propose the method to support derivation process from the visualized relation using Data Envelopment Analysis. Through the experiment, we will confirm the effectiveness of our study.

At an early stage of design process, it is required to discuss many ideas derived from design requirements using designer's knowledge and experiences. Especially, at conceptual design stage, many designers often discuss together about new product and discuss design ideas considering its effectiveness. However, according to increasing the complexity of the functions of products and variety of consumer's needs in recent years, it becomes difficult for designers to discuss about ideas by only conversations and figures. Then, in the conceptual design process, it is required to derive many ideas that meet the design requirement considering the complicated requirements. The derivation process of ideas often wastes the time because of the inertia of designer's thinking process. In this study, we will propose the method to support derivation process from the visualized relation using Data Envelopment Analysis. Through the experiment, we will confirm the effectiveness of our study.

The simulation system that calculates the behavior of the liver by needle insertion in real time, displays the results, and outputs the reaction force to the kinesthetic sense device was developed. The finite element method was used for the calculation of the behavior of the liver. Considering the calculation load, the algorithm to achieve the real-time processing was developed. The simulation system was evaluated from calculating load by using the liver models with different number of elements. It was the model with 905 elements and 209 nods that met the requirement for the real-time processing (calculation speed is 30Hz or more).

This study treats the reduction of the degree of the passenger injury by analyzing the behavior of 133 passengers being in a commuter vehicle at the time of the impact of the railroad accident outbreak with a computer. Judgment the degree of the injury of the passengers and inspection of the global safety was enabled by developing the behavior analysis program of the passengers with cellular automata with C language and analyzing with a large number of people. In addition, the safety improvement effect of the straps was confirmed by comparing the injury judgment value of the model increased the number of the straps to the normal model.

In this research, we analyzed the automotive data that contain bringing the automotive performance from about 300000 models from which they were open to the public from 1982 to 2006 years about 20000 models by Data Envelopment Analysis. DEA is the method that can make clear superiority or inferiority of business unit with multi-dimensional index and showing improvement direction of business unit. As a result, we can show trends from graph where horizontal axis was assigned as each performance index and vertical axis was assigned as each efficiency value obtained by DEA. We showed design index of automotive in the future by sensitivity analysis. From the above-mentioned method, we can confirm DEA is the effective method as method of evaluating products with multi-dimensional index.

In conceptual design phase, if designers are much more conscious of design objectives, they won't come up with various ideas about new product. On the other hand, using brainstorming allow to get various ideas, but to get a lot of unavailable ideas together. In this study, we propose the method that supports generating various and effective ideas in conceptual design. In the last our study, we have proposed conceptual design support method using Data Envelopment Analysis. The last method's approach is using several evaluation values to fill the gap of palate frontier. But it was too difficult for subjects to use this approach in the experiment. Proposed method in this paper supplies key words. These key words are made of calculated component values using made nonlinear mathematical model of relation between component and evaluation of idea with Neural Network. We confirm that the method is useful in terms of simplicity of generating various and effective ideas.

Recently the development of the small satellite becomes active. In general, small satellites are expected to be developed faster and cheaper than the large satellites. The launching cost of the piggyback satellite is low, and then a cost of a piggyback satellite is often decided by weight. Therefore it is important to reduce the weight of satellite for cost. Considering the severe mechanical environment of launching, we have to design of satellite structure. The natural frequency of the satellite should be higher than the value decided by the rocket and the satellite should withstand the loads during launch. In this paper, we will propose the design of the satellite whose dimension is 20 centimeters cube. The satellite supposed to be launched by H-2A rocked and we focused on the trade-off design between minimization of mass and maximization of natural frequency under the maximum stress condition for optimizing the satellite structures.

This paper focuses on the creative aspects of collaboration and proposes a method for analyzing created ideas to help designers to enhance designers' creativity during collaborative design projects. The proposed method is based on DEA (Data Envelopment Analysis), analyses ideas created by designers to reveal characteristics and overall effectiveness of each idea, interrelationship between ideas and potentially fruitful directions for improvement of created ideas and exploration of new ideas and aims to help designers explore more sophisticated ideas. To enable smooth collaboration when using the proposed analysis method, this paper also proposes a computerized support system. This system is based on a combination of the analysis method proposed here, and the method for visualizing interactive communication processes proposed in our previous work. Analyzing system analyzes created ideas and visualizes the results from the multiple viewpoints, whereas visualizing system records interactive communication processes among designers and visualizes them in an easyto-understand way.

This paper presents the development of robot capable to simulate heartbeat. It is difficult to operate off-pump coronary-artery bypass surgery. Consequently, we develop the surgical robot system with heart-beat compensation. In the process of developing the robot system above, it is necessary to evaluate the tracking capability of the robot system quantitatively. Therefore, we developed the Robotic heart-beat simulator which evaluates the robot system. First of all, required specification of the robot was found by the heartbeat data in vivo experiment. Second, the link parameters of the robot that satisfy the specification were optimized. At the end, the robot was evaluated for accuracy of position and posture. As a result, the robot moved with maximum error of 0.28 [mm] and 0.54 [deg]. In addition, the robot was evaluated in the experiment of movement based on the heartbeat data, it showed a little error and time-lag, but utility of the robotic heartbeat simulator.

In this research, we analyzed the automotive market bringing the automotive performance from about 300000 models from which they were open to the public from 1982 to 2006 years about 20000 models by Data Envelopment Analysis. DEA is the method that can make clear about superiority or inferiority of business unit with multi-dimensional index and showing improvement of business unit. As a result, we can show trends from graph where horizontal axis was assigned as each performance index and vertical axis was assigned as each efficiency value obtained by DEA. We showed design index of automotive in the future by sensitivity analysis. From the above-mentioned method, we can confirm DEA is the effective method as method of evaluating products with multidimensional index.

This study treats the reduction of the degree of the passenger injury by analyzing the behavior of the passenger sitting on a box seat at the time of the collision outbreak of the railroad carriage by simulation. Judgment the degree of the passenger injury was enabled by development the behavior analysis program of the passenger with C language and inputting a decelerating acceleration wave pattern at the time of the vehicle collision obtained by the finite element analysis. Injury judgment values decreased by more than 30% by optimizing to assume the spring constant of the seat as a design variable to reduce an injury judgment value.

The surgery simulation system for training purpose is useful for training and planning. The system displays the deformation of the human organs calculated using Finite Element Method (FEM) and output the reaction forces with force feedback devices. However, FEM prevents a real time simulation because of high computational cost. In this study, we have developed a Needle Insertion Surgery Simulation System, which has the ability to compute reaction forces and simulates dynamical behaviors in real time using a simple calculation method. Here, we have proposed and discussed a simple method to compute reaction forces from internal stress distribution, which is calculated using FEM. Considering the DOF of the model and computational cost; we have discussed the effectiveness of the proposed method, and the possibility to develop the system.

The minimal invasive surgical technique used for treatments on cancer infected liver is comparatively to be effective due to fast recovery of the wound and the rehabilitation period. Needle insertion planning shows its difficulties when needle contact the tissue structures and become complicated with existence of gravity, cancer size and position, needle properties and surrounding organs. In this study, a constitutive equation of viscoelastic material properties of liver is formulated using measured experimental results on pig′s liver. 3-D Finite Element Model is created using sliced MRI images. Approximations were made on friction between needle and soft tissue, and the condition of tear-off elements integrated with quasi-static analysis. In simulation, we proposed a retainer tool to minimize the displacement of the cancer infected part as a new boundary condition. Numerical results by proposed boundary condition technique show the possibility to design a new device in order to navigate needle to hit the cancer precisely.

The medical insertion treatments on cancer infected liver seem to be very effective because of low invasion for patients. Planning for insertion procedure is difficult because the interaction between needle and soft tissue become complicated and the liver may deform largely under the influence of such gravity, cancer, position of needle and so on. It is of significant to grasp natural properties and deformations of liver during medical needle insertion. In this study, viscoelastic material properties are measured by experiments and constitutive equation is formulated based on the experimental results. Then a liver is modeled by finite elements made from the sliced MRI images. 3-Dimensional needle insertion procedures are simulated by quasi-static analysis assuming friction between the needle and soft tissue and conditions of tear-off elements. From the numerical results by the proposed simulation method, it is found that some navigation of the needle insertion is necessary to hit the cancer correctly.

Particle Swam Optimization is one of useful optimization method that has a global search ability and is easy to implement. However there are some difficulties are observed for behavior constraints. This paper proposes a new approach to treat behavior constrains by projection of velocity vector of particles. By projection of velocity vector particks could approach feasible region formed by active constraints. Through several numerical examples, it is recognized better converge performance than original PSO. Copyright © 2006 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

In this study, we proposed partially rigidizable inflatable structures consist of rigidizable layers on the part where to be stiffened. As a result of tension test of the test specimen, we could make the property of the material clear. Furthermore, we made a initial model that wholly covered hemisphere structural model and the topology optimization was applied to find the optimum arrangement of regidizable layers. As a result, the number of edge reduced to 35 lines, and considering the volume to 11% lower than that of the basic model. From the point of view of manufacturing, stiffness and stress concentration, we could suppose that the basic model is suitable for our required.

This paper focuses on the creative aspects of collaboration and proposes a method for analyzing created ideas to support collaborative design processes. The proposed method, based on DEA (Data Envelopment Analysis), analyses created ideas, reveals their characteristics and interrelationships, clarifies potential directions for improvement of created ideas as well as potentially fruitful directions for exploration of new ideas, and aims to help designers explore more sophisticated products. To enable smooth collaboration when using the proposed method, a computerized support system is constructed. This system is based on a combination of the analysis method proposed here, and the method for visualizing interactive communication processes proposed in our previous work.

In this study, we will review the previous studies treating same problem using FEM analysis and propose the method to treat the cutting simulation considering real time computation and simulation results are directly transferred to the user through the haptic device. The hex and tetra elements were used to model the structure using FEM analysis and dynamical response was calculated using Wilson-theta method. Here, the elements matrix was normalized according to the distance between a cutting device and nodes to omit the re-mesh procedures. The proposed method was implemented using three threads that handle graphics for display, dynamical calculation and model construction to improve the response for user operation. Then, we have developed the simulation system composed of the haptic device (PHANToM force feedback device) using ToolKit and the proposed method including graphics animation. Using the haptic device, we have been able to discuss about the obtained feeling through the device and obtain experimental results and compared from the points of view of the previous simple calculation method and the proposed method, the obtained reaction forces. We could confirm that the performances of the developed system using thread is very good and effective for the further improvement using detail calculation on FEM, the qualitative feelings and quantitatively obtained reaction forces are different among the compared method. Then, we could confirm the some properties and the effectiveness of the proposed method and the developed system.

This paper shows the development of a respiratory surgical navigation system for the metastasis cancer in a collapsed lung. This system has two navigation methods, (a) Collapsed simulation,(b) Palpation using manipulator. Collapsed simulation provides the position of the cancer in a collapsed lung using the preoperative CT Data. Palpation using manipulator after collapsed simulation provide more precise position of collapsed lung.

In this study, we will review the previous studies treating same problem using FEM analysis and propose the method to treat the cutting simulation considering real time computation and simulation results are directly transferred to the user through the haptic device. The hex and tetra elements were used to model the structure using FEM analysis and dynamical response was calculated using wilson θ method. Here, the elements matrix was normalized according to the distance between a cutting device and nodes to omit the re-mesh procedures. The proposed method was implemented using three threads that handle graphics for display, dynamical calculation and model construction to improve the response for user operation. Then, we have developed the simulation system composed of the haptic device (PHANToM force feedback device) using ToolKit and the proposed method including graphics animation.

While calculation of reaction force in object cutting, we have to subdivide the original mesh of finite element method in the field where the stress concentration can be observed. It causes a huge computational complexity. We constructed object cutting simulation system that is able to output reaction force to force feedback device using OpenGL library. The system consists of high speed deformation calculation using rough mesh, and static and dynamic calculation method of calculates reaction force to cutting tool.

Inverse offsetting is a special type of Minkowski sum operation with a solid model and an in versed shape of a milling cutter. In the NC machining, geometric simulations of the milling operation are often performed prior to the actual machining to visualize the result shape of the workpiece. Inverse offsetting of this workpiece shape is useful for automating some process planning tasks, especially, a task for determining milling regions for the following machining operations. Most milling, simulation programs use discrete Z-map models for representing the workpiece shape. In this paper, an algorithm for inverse of map model is offsetting the Z proposed Our algorithm computes dense zig-zag curves covering the Z-map model, then it generates the swept volume of the inversed cutter moving along the curves to obtain the inverse offset shape of the model. Proposed algorithm is implemented and an experimental process planning assistance program using this technology is demonstrated.

In the mechanical design problems, the design variables that designers can be satisfied have to be derived using as the optimization method and the satisfying designing method. However, in order to grasp the influence to the performance (objective function) and conditions (constraints) that each parameter does, the value of design variables is often changed manually and repeating examination. This is called Parameter Study. In this paper, in order to perform a Parameter Study usually, We have developed the Parameter Study Tool using SD-Graphics. We have confirmed the usefulness of the parameter study Tool, though some numerical examples.

In the mechanical design problems, the design variables that designers can be satisfied have to be derived using as the optimization method and the satisfying designing method. However, in order to grasp the influence to the performance (objective function) and conditions (constraints) that each parameter does, the value of design variables is often changed manually and repeating examination. This is called Parameter Study. In this paper, in order to perform a Parameter Study usually, We have developed the Parameter Study Tool using SD-Graphics. We have confirmed the usefulness of the parameter study Tool, though some numerical examples.

In some cases of developing a new product, response surface of an objective function is not always single peaked function, and it is often multi-peaked function. In that case, designers would like to have not only global optimum solution but also as many local optimum solutions as possible, so that he or she can select one out of them considering the other conditions that are not taken into account priori to optimization. Although this information is quite useful, it is not that easy to obtain with single trial of optimization. In this study, we will propose a screening of fitness function in genetic algorithms, and give rough search for local optima. Once after they are obtained we will carry out local search to obtain multiple quasi-optimum solutions. In this paper, we demonstrate the effectiveness of the proposed method through a simple benchmark test problem.

In design problems, designers have to decide many properties of products to satisfy requirements from users or market. The designers also have to consider the environment under the use of the products and the environment is often unpredictable or difficult to be determined in detail. The optimization techniques are useful to support the designers to decide the properties of the product. However, it is required before the application of the optimization techniques to formulate mathematical models and it is difficult to formulate the all properties of products, for examples preferences of the customer. In this situation, it seems to be useful to derive several solutions that equip the variety or diversity about the value of design variables or objective functions. In this paper, the new method to derive several solutions using immune algorithms is described. The proposed method equips the interaction mechanism between the design parameter and the environment parameters. Through some numerical examples of the structural design problems and job-shop scheduling problems, the effectiveness is confirmed.

Job-Shop Scheduling Problems (JSSPs) are important problems that decide production scheduling. However these problems are not easy to solve and many studies have been done. Furthermore, in real situation, while doing jobs according to decided schedule, re-scheduling occurs because of new jobs and it is required to decide the schedule considering ability and skills of works.
In this study, in the stage of the deciding the JSSPs, we will discuss the method to offer the designer several candidates of the JSP and then designers can select the final schedule considering the difficult properties to formulate the problems. Through some numerical examples, we will confirm the effectiveness of the proposed method.

Job-shop scheduling problems (JSSPs) are important problems that decide production scheduling. However these problems are not easy to solve and many studies have been done. Furthermore, in real situation, while doing jobs according to decided schedule, re-scheduling occurs because of new jobs and it is required to decide the schedule considering ability and skills of works. In this study, in the stage of the deciding the JSSPs, we will discuss the method to offer the designer several candidates of the JSP and then designers can select the final schedule considering the difficult properties to formulate the problems. Through some numerical examples, we will confirm the effectiveness of the proposed method.

In the mold part machining, rough milling with large cutters is applied first to efficiently remove excess material, then milling operation with small cutters finishes the mold surface. Large cutters cannot remove sufficient material at hollow shapes of the mold, therefore manufacturing engineers must apply some additional milling operations with medium size cutters prior to the finishing. Process planning of such semi-finishing operations, especially determination of the milling region with large remained material is currently done based on a manual extraction of the hollow shape using the machine drawing. In this paper, the authors propose an algorithm for automating the hollow shape extraction. This algorithm uses the inverse offset computation and milling simulation in the process, which are known very time-consuming. In order to boost the computation speed, the rendering hardware based acceleration technology is introduced. Proposed algorithm is implemented and an experimental system for assisting the process planning of the semi-finishing operation is demonstrated.

In design processes of machinery, much computer software, for examples CAD/CAE/CAM software, are used. The design processes are aided by this software. The seamless connections of the design processes are necessary for the improvement of the cost benefit of the products. However, sometimes, the conflicts among designs or design processes are occurred by the change of the design at a certain design process and these conflicts are should be noticed and solved immediately. In this research, we have developed the design system including CAD software and the developed system has some functions to find the conflicts of the change of designs and to solve the conflicts. We use Data Envelopment Analysis (DEA) to calculate the efficiency of the design and Satisficing Trade-off Method (STM) to find and solve the conflicts. We have confirmed through some fundamental numerical examples and discussed of the proposed system and method and showed the effectiveness of out study.

Optimization techniques are useful to determine the unknown parameter according to the evaluations of design. This techniques require to be formulated mathematically. Then the indexes that is difficult to express mathematically, for examples "kansei" are difficult to be included in the optimization problems. In this study, we will propose the algorism based on immune algorithms and try to derive some candidates including solution. immune algorithms are considered as the optimization algorithms. However, the immune algorithms are not fully established becase various algorithms are considered and fully investigated. In this study, from above point of view, we will propose the immune algorithm that treates the "antibody-antigen reaction". Through some numerical examples, we will show the effectivenews of th proposed algorithm.

Optimization techniques are useful to determine the unknown parameter according to the evaluations of design. This techniques require to be formulated mathematically. Then the indexes that is difficult to express mathematically, for examples "kansei" are difficult to be included in the optimization problems. In this study, we will propose the algorism based on immune algorithms and try to derive some candidates including solution. immune algorithms are considered as the optimization algorithms. However, the immune algorithms are not fully established becase various algorithms are considered and fully investigated. In this study, from above point of view, we will propose the immune algorithm that treates the "antibody-antigen reaction". Through some numerical examples, we will show the effectivenews of th proposed algorithm.

In recent years, financial difficulties led engineers to look for not only the efficiency of the function of a product but also the cost of its development. In order to reduce the time for the development, engineers in each disciplinary have to develop and improve their objectives collaboratively. Sometimes, they have to cooperate with those who have no knowledge at all for their own disciplinary. Collaborative designs have been studied to solve these kinds of the problems, but most of them need some sorts of negotiation between disciplines and assumed that the negotiation will be done successfully. However, in the most cases of real designs, manager of each disciplinary does not want to give up his or her own objectives to stress on the other objectives. In order to carry out these negotiation smoothly, we need some sort of evaluation criteria which will show efficiency of the product considering the designs made up by each division and if possible, considering the products of the competitive company. In this study, we use Data Envelopment Analysis (DEA) to calculate the efficiency of the design and showed every decision maker the directions of the development of the design. We newly called these kinds of systems as supervisor systems and implemented these systems in computer networks that every decision makers can use conveniently. Through simple numerical examples, we showed the effectiveness of the proposed method.

In recent years, financial difficulties led engineers to look for not only the efficiency of the function of a product but also the cost of its development. In order to reduce the time for the development, engineers in each disciplinary have to develop and improve their objectives collaboratively. Sometimes, they have to cooperate with those who have no knowledge at all for their own disciplinary. Collaborative designs have been studied to solve these kinds of the problems, but most of them need some sorts of negotiation between disciplines and assumed that the negotiation will be done successfully. However, in the most cases of real designs, manager of each disciplinary does not want to give up his or her own objectives to stress on the other objectives. In order to carry out these negotiation smoothly, we need some sort of evaluation criteria which will show efficiency of the product considering the designs made up by each division and if possible, considering the products of the competitive company. In this study, we use Data Envelopment Analysis (DEA) to calculate the efficiency of the design and showed every decision maker the directions of the development of the design. We newly called these kinds of systems as supervisor systems and implemented these systems in computer networks that every decision makers can use conveniently. Through simple numerical examples, we showed the effectiveness of the proposed method.

Many optimization methods and practical softwares have been developing for many years and most of them are very effective, especially to solve practical problems. But, non-linearity of objective functions and constraint functions, which have frequently seen in practical problems, has caused a difficulty in optimization. This difficulty mainly lies in the existence of several local optimum solutions. In this study, we have proposed a new global optimization methodology that provides an information exchange mechanism in the nearest neighbor method. We have developed a simple software system, which treated each design point in optimization as an agent. Many agents can search the optima simultaneously exchanging the their information. We have defined two roles of the agents. Local search agents have roles on searching local optima by such an existing method as the steepest decent method and so on. Stochastic search agents investigate the design space by making use of the information from other agents. Through simple and several structural optimization problems, we have confirmed the advantages of the method.

Many optimization methods and practical softwares have been developing for many years and most of them are very effective, especially to solve practical problems. But, non linearity of objective functions and constraint functions, which have frequently seen in practical problems, has caused a difficult situation for optimization. This difficulty mainly lies in the existence of several local optimum solutions. In this study, we have proposed a new global optimization methodology that provides an information exchange mechanism in the nearest neighbour method. We have developed a simple software system, which treated each design point in optimization as an agent. Many agents can search the optima simultaneously exchanging the their information. We have defined two roles of the agents. Local search agents have roles on searching local optima by an existing method like the steepest decent method and so on. Stochastic search agents investigate the design space by making use of the information from other agents. Through simple and several structural optimization problems, we have confirmed the advantages of this method.

Immune system in mammals plays a significant role on the survival in the case with attacking of various bacteria. This system seems to equip the mechanism eliminate the various vacteria. From the view point of information mechanism, this system could offer the designs that are considered with the environmental situation, for example, wind loads, deterioration and so on. Especially, immune algorithms are considered as the optimization algorithms. However, the immune algorithms are not fully established becase various algorithms are considered and fully investigated. In this study, from above point of view, we will propose the immune algorithm that treates the "antibody-antigen reaction". Through some numerical examples, we will show the effectivenews of th proposed algorithm.

Immune system in mammals plays a significant role on the survival in the case with attacking of various bacteria. This system seems to equip the mechanism eliminate the various vacteria. From the view point of information mechanism, this system could offer the designs that are considered with the environmental situation, for example, wind loads, deterioration and so on. Especially, immune algorithms are considered as the optimization algorithms. However, the immune algorithms are not fully established becase various algorithms are considered and fully investigated. In this study, from above point of view, we will propose the immune algorithm that treates the "antibody-antigen reaction". Through some numerical examples, we will show the effectivenews of th proposed algorithm.

Recent years, computational power has been incresing and designers could discuss design problems from several points of view. In these discussions, simulations using computers could offer useful information to evaluate their designs to develop profitable products exceeding the competitor's product. Optimization methods offer reasonable design canditates. However, in the design in which some technical fields are included, it is difficult to make decision to settle design canditates. In our previous study, we have proposed the method that led designers to collaboration and developed the software system. In this paper, we have examined the developed system through the some design problems.

Many optimization methods and practical softwares have been developing for many years and most of them are very effective, especially to solve practical problems. But, non linearity of objective functions and constraint functions, which have frequently seen in practical problems, has caused a difficult situation for optimization. This difficulty mainly lies in the existence of several local optimum solutions. In this study, we have proposed a new global optimization methodology that provides an information exchange mechanism in the nearest neighbour method. We have developed a simple software system, which treated each design point in optimization as an agent. Many agents can search the optima simultaneously exchanging the their information. We have defined two roles of the agents. Local search agents have roles on searching local optima by an existing method like the steepest decent method and so on. Stochastic search agents investigate the design space by making use of the information from other agents. Through simple and several structural optimization problems, we have confirmed the advantages of this method. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.

In the design of products, the designers often have to improve some objects and to satisfy some constraints. Furthermore, these days, it is more important than before to design and develop the products shortly and to commercialize the products for the profit. These needs time-consuming decision-makings and we often treat this problem as multi-objective design problems. However it is difficult for the designers who have no knowledge of the other disciplines when to decide the design collaboratively. Therefore, in this paper, we proposed a method to show some compromise to the designers and developed a system operated through computer network. © 2000 The American Institute of Aeronautics and Astronautics Inc. All rights reserved.

Recent years, financial difficulties led engineers to look for not only the efficiency of the function of a product but also the cost of its development. In order to reduce the time for the development, engineers in each discipline have to develop and improve their objectives collaboratively. Sometimes, they have to cooperate with those who have no knowledge at all for their own disciplines. Collaborative designs have been studied to solve these negotiations will be done successfully. However, in the most cases of real designs, manager of each discipline does not want to give up his or her own objectives to stress on the other objectives. In order to carry out these negotiations smoothly, we need some sort of evaluation criteria which will show efficiency of the product considering the designs by each division and if possible, considering the products of the competitive company, too. In this study, we use data Envelopment Analysis (DEA) to calculate the efficiency of the design and showed every decision maker the directions of the development of the design. We will call here these kinds of systems as supervisor systems and implemented these systems in computer networks that every decision maker can use conveniently. Through simple numerical examples, we showed the effectiveness of the proposed method.

We, human being, have survived and prosperd in a biological systems and an immute system plays a significant roll in protecting us against foregin bacillus. From the results of the study field in information processing, it is pointed out that the immute system is capable of learning, memory, pattern recognition and optimization using genetic operators. In the optimization of mechanical and structural designs, an environment of products is significant factor to decide the design. In this study, we will treate the design variables in the optimization problem as antibody and the environment as the antigen. We treated simple numerical examples and they resulted the design stored in memory-cell with best evaluation and worst evaluation considering environment. We have confirmed that the design canditates including the design obtained by mathematical programming are found among the results.

In recent years, financial difficulties led engineers to look for not only the efficiency of the function of a product but also the cost of its development. In order to reduce the time for the development, engineers in each disciplinary have to develop and improve their objectives collaboratively. Sometimes, they have to cooperate with those who have no knowledge at all for their own disciplinary. Collaborative designs have been studied to solve these kinds of the problems, but most of them need some sorts of negotiation between disciplines and assumed that these negotiation will be done successfully. However, in the most cases of real designs, manager of each disciplinary does not want to give up his or her own objectives to stress on the other objectives. In order to carry out these negotiation smoothly, we need some sort of evaluation criteria which will show efficiency of the product considering the designs made up by each division and if possible, considering the products of the competitive company. In this study, we use Data Envelopment Analysis (DEA) to calculate the efficiency of the design and showed every decision maker the directions of the development of the design. We newly called these kinds of systems as supervisor systems and implemented these systems in computer networks that every decision makers can use conveniently. Through simple numerical examples, we showed the effectiveness of the proposed method. © 2000, The Japan Society of Mechanical Engineers. All rights reserved.

In recent years, multi-agent architectures which have been studied in the field of artificial intelligence might attract a great deal of attention to the ability of the cooperative properties for engineering. In this study, we proposed a new approach to find the improved design in the layout design and shape design problems of framed structures by applying the multi-agent architectures. We considered each agent as an element in Finite Element Analysis and proposed modification rules for the layout shape of the structure. Following this approach, each agent proposes modification plans based on his or her evaluate function. The proposed plans are picked up or rejected by communication among agents and the remained plans may improve a design created from an initially simple structure. We developed the simulation system running on the UNIX and considerations have been given to the simple truss structural design and some advantages of the proposed have been shown and confirmed.

Application of genetic algorithms to mixed design variable optimization has received wide recognition. However, there are some problems in expressing continuous number in GAs, and according to that, applications to mixed variables has not been successful as it recognized. We have developed Adaptive Range Genetic Algorithms and overcome most of the difficulties in expressing continuous and discrete numbers in Genetic Algorithms and obtain the best results in some simple bench mark problems. Key success lies in the adaptation of searching range according to the situation of generation and existence of gene. And this conclusion is different from what they said in Evolution Algorithms (EAs). In EAs, they use continuous number directly to chromosome and made up some rules in crossing over. They ignore the existence of gene to treat design variables. If their keys in success lie in the expression of continuous numbers, we thought existence of gene in ARange GAs will influence badly in its convergence. From this stand point view, we will examine the necessity of gene in GAs and compare the results that are obtained from one of the EAs method called BLX alpha method. From these comparisons, even though we do not use the information of population in the generation, we have obtained better convergence, because gene will give some deterministic value in each generation and combination of parents. In that sense, BLX alpha method is something like random search and it only happened to find good solution. Thus, we can say that gene will introduce some sorts of deterministic characteristics in genetic search and it will distinguish GAs from just random search technique. From this conclusion we intend to say the needs of gene in GAs.

Application of genetic algorithms to mixed design variable optimization has received wide recognition. However, there are some problems in expressing continuous number in GAs, and according to that, applications to mixed variables has not been successful as it recognized. We have developed Adaptive Range Genetic Algorithms and overcome most of the difficulties in expressing continuous and discrete numbers in Genetic Algorithms and obtain the best results in some simple bench mark problems. Key success lies in the adaptation of searching range according to the situation of generation and existence of gene. And this conclusion is different from what they said in Evolution Algorithms (EAs). In EAs, they use continuous number directly to chromosome and made up some rules in crossing over. They ignore the existence of gene to treat design variables. If their keys in success lie in the expression of continuous numbers, we thought existence of gene in ARange GAs will influence badly in its convergence. From this stand point view, we will examine the necessity of gene in GAs and compare the results that are obtained from one of the EAs method called BLX alpha method. From these comparisons, even though we do not use the information of population in the generation, we have obtained better convergence, because gene will give some deterministic value in each generation and combination of parents. In that sense, BLX alpha method is something like random search and it only happened to find good solution. Thus, we can say that gene will introduce some sorts of deterministic characteristics in genetic search and it will distinguish GAs from just random search technique. From this conclusion we intend to say the needs of gene in GAs.

In recent years, multi-agent architectures which have been studied in the field of artificial intelligence might attract a great deal of attention to the ability of the cooperative properties for engineering. In this study, we proposed a new approach to find the improved design in the layout design and shape design problems of framed structures by applying the multi-agent architectures. We considered each agent as an element in Finite Element Analysis and proposed modification rules for the layout shape of the structure. Following this approach, each agent proposes modification plans based on his or her evaluate function. The proposed plans are picked up or rejected by communication among agents and the remained plans may improve a design created from an initially simple structure. We developed the simulation system running on the UNIX and considerations have been given to the simple truss structural design and some advantages of the proposed have been shown and confirmed. © 1999, The Japan Society of Mechanical Engineers. All rights reserved.

In conventional optimum design process, symbolic formulation of mathematical optimization problem usually must be done by the designers before numerical computation. And these pre-process tasks are sometimes tremendously hard and time consuming for the designers. In this paper, we will show a simplification of these pre-process tasks with an aid of symbolic manjpulation systems which have been studied in the field of Artificial Intelligence. In almost existent symbolic manipulation systems, their main purposes being stressed on verifying the expression, the computer programs in the systems could not obtain any information directly from the operator during the excuting of the program. In this study, to reduce this disadvantage we use menu system as interactive computer system to define and decide the objective function and constraints freely. And, we applied a symbolic manupulation system to a formulation of the objective function and the constraints as well as to structural analysis by Energy method. Consideration have been given to the obtained optimum designs and the effectiveness was confirmed.