Updated on 2021/12/08

写真a

 
KASAI, Hiroyuki
 
Affiliation
Faculty of Science and Engineering, School of Fundamental Science and Engineering
Job title
Professor
Profile
Hiroyuki KASAI (HK) received his B.Eng., M.Eng., and Dr.Eng. degrees in Electronics, Information, and Communication Engineering from WASEDA University, Tokyo, Japan in 1996, 1998, and 2000, respectively. He was a research associate at Global Information and Telecommunication Institute (GITI), WASEDA University, during 1998-2002. He was a visiting researcher at British Telecommunication BTexacT Technologies, the U.K. during 2000-2001. He joined Network Laboratories, NTT DoCoMo, Japan, in 2002. He was an associate professor at The University of Electro-Communications (UEC), Tokyo, during 2007-2019, and he was appointed as a professor at UEC in 2019. He was a senior policy researcher at Council for Science, Technology and Innovation Policy (CSTP), Cabinet Office of Japan, during 2011-2013. He was a visiting researcher at Technical University of Munich (TUM), Germany, during 2014-2015. Since September 2019, he has been a full professor at WASEDA University.

Concurrent Post

  • Faculty of Science and Engineering   Graduate School of Fundamental Science and Engineering

Research Institute

  • 2020
    -
    2022

    国際情報通信研究センター   兼任研究員

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Education

  • 1998.04
    -
    2000.03

    Waseda University   Graduate School, Division of Science and Engineering   Electronics and Communication  

  • 1996.04
    -
    1998.03

    Waseda University   Graduate School, Division of Science and Engineering   Electronics and Communication  

Degree

  • 早稲田大学   博士(工学)

Research Experience

  • 2014.04
    -
    2015.08

    Technical University of Munich   Visiting Researcher

  • 2011.04
    -
    2013.02

    Cabinet Office of Japan   Senior Policy Researcher at Council for Science, Technology and Innovation Policy (CSTP)

  • 2013.01
    -
     

    Gnzo, Inc.   Director

  • 2010.06
    -
    2012.01

    Gnzo Inc.   Director

  • 2002.05
    -
    2007.03

    NTT DoCoMo Inc.   Researcher

  • 1998.10
    -
    2002.03

    Waseda University Global Intenational Telecommunication Institute   Associate Researcher

  • 2000.07
    -
    2001.09

    U.K. British Telecom BTexact Technologies   Visiting Researcher

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Professional Memberships

  •  
     
     

    Information Processing Society of Japan (IPSJ)

  •  
     
     

    The Japan Society for Industrial and Applied Mathematics - JSIAM

  •  
     
     

    The Institute of Electronics, Information and Communication Engineers (IEICE)

  •  
     
     

    The Institute of Electrical and Electronic Engineers (IEEE)

 

Research Areas

  • Intelligent informatics

  • Mathematical informatics

Research Interests

  • Network

  • Signal Processing

  • Media Recognition

  • Medica Processing

  • Video Transmission

  • Video Codec

  • Multimedia Communications

  • Machine Learning

  • Data Learning and Analysis

  • 信号処理,

  • メディア認識

  • メディア処理

  • 映像伝送

  • 映像符号化

  • ネットワーク解析

  • データ学習・解析

  • 機械学習

  • Optimization

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Papers

  • Riemannian adaptive stochastic gradient algorithms on matrix manifolds

    Hiroyuki Kasai, Pratik Jawanpuria, Bamdev Mishra

    36th International Conference on Machine Learning (ICML2019)   PMLR  2019.06  [Refereed]

  • Riemannian stochastic variance reduced gradient algorithm with retraction and vector transport

    Hiroyuki Sato, Hiroyuki Kasai, Bamdev Mishra

    SIAM Journal on Optimization (SIOPT)   29 ( 2 ) 1444 - 1472  2019.05  [Refereed]

    DOI

  • リーマン多様体上の確率的最適化の発展

    佐藤寛之, 笠井裕之, Bamdev Mishra

      2108   168 - 176  2019.04  [Invited]

  • A Riemannian gossip approach to subspace learning on Grassmann manifold

    Bamdev Mishra, Hiroyuki Kasai, Pratik Jawanpuria, Atul Saroop

    Machine Learning     1 - 21  2019.01  [Refereed]

    DOI

  • McTorch, a manifold optimization library for deep learning

    Mayank Meghwanshi, Pratik Jawanpuria, Anoop Kunchukuttan, Hiroyuki Kasai, Bamdev Mishra

    NIPS workshop on Machine Learning Open Source Software (MLOSS2018)   1  2018.12  [Refereed]

  • Stochastic optimization library: SGDLibrary

    Hiroyuki Kasai

    NIPS workshop on Machine Learning Open Source Software (MLOSS2018)   1  2018.12  [Refereed]

  • Inexact trust-region algorithm on Riemannian manifolds

    Hiroyuki Kasai, Bamdev Mishra

    32nd Conference on Neural Information Processing Systems (NeurIPS2018) (formerly NIPS)   1  2018.12  [Refereed]

  • Fast optimization algorithm on complex oblique manifold for hybrid precoding in Millimeter Wave MIMO systems

    Hiroyuki Kasai

    6th IEEE Global Conference on Signal and Information Processing (GlobalSIP2018)   Accepted  2018.11  [Refereed]

  • Accelerated stochastic multiplicative update with gradient averaging for nonnegative matrix factorizations

    Hiroyuki Kasai

    26th European Signal Processing Conference (EUSIPCO2018)     2593 - 2597  2018.09  [Refereed]

    DOI

  • Riemannian joint dimensionality reduction and dictionary learning on symmetric positive definite manifolds

    Hiroyuki Kasai, Bamdev Mishra

    26th European Signal Processing Conference (EUSIPCO2018)     2010 - 2014  2018.09  [Refereed]

    DOI

  • Low-rank geometric mean metric learning

    Mukul Bhutani, Pratik Jawanpuria, Hiroyuki Kasai, Bamdev Mishra

    ICML workshop on Geometry in Machine Learning (GiMLi2018)   0  2018.07  [Refereed]

  • Stochastic recursive gradient on Riemannian manifolds

    Hiroyuki Kasai, Hiroyuki Sato, Bamdev Mishra

    ICML workshop on Geometry in Machine Learning (GiMLi2018)   1  2018.07  [Refereed]

  • Riemannian stochastic recursive gradient algorithm

    Hiroyuki Kasai, Hiroyuki Sato, Bamdev Mishra

    35th International Conference on Machine Learning (ICML2018)   PMLR 80   2516 - 2524  2018.07  [Refereed]

  • SGDLibrary: A MATLAB library for stochastic optimization algorithms

    Hiroyuki Kasai

    Journal of Machine Learning Research (JMLR)   18 ( 215 ) 1 - 5  2018.06  [Refereed]

     View Summary

    We consider the problem of finding the minimizer of a function f:ℝd→ℝ of the finite-sum form minf(w)=1/n∑nifi(w). This problem has been studied intensively in recent years in the field of machine learning (ML). One promising approach for large-scale data is to use a stochastic optimization algorithm to solve the problem. SGDLibrary is a readable, flexible and extensible pure-MATLAB library of a collection of stochastic optimization algorithms. The purpose of the library is to provide researchers and implementers a comprehensive evaluation environment for the use of these algorithms on various ML problems.

  • Stochastic variance reduced multiplicative update for nonnegative matrix factorization

    Hiroyuki Kasai

    43rd IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2018)     6338 - 6342  2018.04  [Refereed]

    DOI

  • Riemannian stochastic quasi-Newton algorithm with variance reduction and its convergence analysis

    Hiroyuki Kasai, Hiroyuki Sato, Bamdev Mishra

    21st International Conference on Artificial Intelligence and Statistics (AISTATS2018)   PMLR 84   269 - 278  2018.04  [Refereed]

     View Summary

    Stochastic variance reduction algorithms have recently become popular for minimizing the average of a large, but finite number of loss functions. The present paper proposes a Riemannian stochastic quasi-Newton algorithm with variance reduction (R-SQN-VR). The key challenges of averaging, adding, and subtracting multiple gradients are addressed with notions of retraction and vector transport. We present convergence analyses of R-SQN-VR on both non-convex and retraction-convex functions under retraction and vector transport operators. The proposed algorithm is evaluated on the Karcher mean computation on the symmetric positive-definite manifold and the low-rank matrix completion on the Grassmann manifold. In all cases, the proposed algorithm outperforms the state-of-the-art Riemannian batch and stochastic gradient algorithms.

  • Riemannian Optimization: Fundamental and Research Trends

    Hiroyuki Sato, Hiroyuki Kasai

    システム制御情報学会学会誌「システム/制御/情報」   62 ( 1 ) 21 - 27  2018.01  [Refereed]  [Invited]

    DOI

  • Sparse representation based classification with intra-class variation dictionary on symmetric positive definite matrices

    Hiroyuki Kasai, Kohei Yoshikawa

    IEEE International Symposium on Signal Processing and Information Technology (ISSPIT2017)   0 ( 0 ) 0 - 0  2017.12  [Refereed]

    DOI

  • State duration and interval modeling in hidden semi-Markov model for sequential data analysis

    Hiromi Narimatsu, Hiroyuki Kasai

    ANNALS OF MATHEMATICS AND ARTIFICIAL INTELLIGENCE   81 ( 3-4 ) 377 - 403  2017.12  [Refereed]

     View Summary

    Sequential data modeling and analysis have become indispensable tools for analyzing sequential data, such as time-series data, because larger amounts of sensed event data have become available. These methods capture the sequential structure of data of interest, such as input-output relations and correlation among datasets. However, because most studies in this area are specialized or limited to their respective applications, rigorous requirement analysis of such models has not been undertaken from a general perspective. Therefore, we particularly examine the structure of sequential data, and extract the necessity of "state duration" and "state interval" of events for efficient and rich representation of sequential data. Specifically addressing the hidden semi-Markov model (HSMM) that represents such state duration inside a model, we attempt to add representational capability of a state interval of events onto HSMM. To this end, we propose two extended models: an interval state hidden semi-Markov model (IS-HSMM) to express the length of a state interval with a special state node designated as "interval state node"; and an interval length probability hidden semi-Markov model (ILP-HSMM) which represents the length of the state interval with a new probabilistic parameter "interval length probability." Exhaustive simulations have revealed superior performance of the proposed models in comparison with HSMM. These proposed models are the first reported extensions of HMM to support state interval representation as well as state duration representation.

    DOI

  • State duration and interval modeling in hidden semi-Markov model for sequential data analysis

    Hiromi Narimatsu, Hiroyuki Kasai

    Annals of Mathematics and Artificial Intelligence   81 ( 3-4 ) 377 - 403  2017.12  [Refereed]

     View Summary

    Sequential data modeling and analysis have become indispensable tools for analyzing sequential data, such as time-series data, because larger amounts of sensed event data have become available. These methods capture the sequential structure of data of interest, such as input-output relations and correlation among datasets. However, because most studies in this area are specialized or limited to their respective applications, rigorous requirement analysis of such models has not been undertaken from a general perspective. Therefore, we particularly examine the structure of sequential data, and extract the necessity of “state duration” and “state interval” of events for efficient and rich representation of sequential data. Specifically addressing the hidden semi-Markov model (HSMM) that represents such state duration inside a model, we attempt to add representational capability of a state interval of events onto HSMM. To this end, we propose two extended models: an interval state hidden semi-Markov model (IS-HSMM) to express the length of a state interval with a special state node designated as “interval state node”
    and an interval length probability hidden semi-Markov model (ILP-HSMM) which represents the length of the state interval with a new probabilistic parameter “interval length probability.” Exhaustive simulations have revealed superior performance of the proposed models in comparison with HSMM. These proposed models are the first reported extensions of HMM to support state interval representation as well as state duration representation.

    DOI

  • 直交制約つき最適化問題に対するリーマン多様体上の確率的分散縮小勾配法

    佐藤寛之, 笠井裕之, Bamdev Mishra

    京都大学数理解析研究所講究録   2027   125 - 134  2017

  • A Riemannian gossip approach to decentralized matrix completion

    Bamdev Mishra, Hiroyuki Kasai

    9th NIPS workshop on optimization for machine learning (OPT2016)   1  2016.12  [Refereed]

  • Riemannian stochastic variance reduced gradient on Grassmann manifold

    Hiroyuki Kasai, Hiroyuki Sato, Bamdev Mishra

    9th NIPS workshop on optimization for machine learning (OPT2016)   1  2016.12  [Refereed]

  • Network Volume Anomaly Detection and Identification in Large-Scale Networks Based on Online Time-Structured Traffic Tensor Tracking

    Hiroyuki Kasai, Wolfgang Kellerer, Martin Kleinsteuber

    IEEE TRANSACTIONS ON NETWORK AND SERVICE MANAGEMENT   13 ( 3 ) 636 - 650  2016.09  [Refereed]

     View Summary

    This paper addresses network anomography, that is, the problem of inferring network-level anomalies from indirect link measurements. This problem is cast as a low-rank subspace tracking problem for normal flows under incomplete observations and an outlier detection problem for abnormal flows. Since traffic data is large-scale time-structured data accompanied with noise and outliers under partial observations, an efficient modeling method is essential. To this end, this paper proposes an online subspace tracking of a Hankelized time-structured traffic tensor for normal flows based on the Candecomp/PARAFAC decomposition exploiting the recursive least squares algorithm. We estimate abnormal flows as outlier sparse flows via sparsity maximization in the underlying under-constrained linear-inverse problem. A major advantage is that our algorithm estimates normal flows by low-dimensional matrices with time-directional features as well as the spatial correlation of multiple links without using the past observed measurements and the past model parameters. Extensive numerical evaluations show that the proposed algorithm achieves faster convergence per iteration of model approximation and better volume anomaly detection performance compared to state-of-the-art algorithms.

    DOI

  • Riemannian Stochastic Variance Reduced Gradient on Grassmann Manifold

    Hiroyuki Kasai, Hiroyuki Sato, Bamdev Mishra

    The fifth International Conference on Continuous Optimization   1  2016.08  [Refereed]

  • Low-rank tensor completion: a Riemannian manifold preconditioning approach

    Hiroyuki Kasai, Bamdev Mishra

    33rd International Conference on Machine Learning (ICML2016)   PMLR 48   1012 - 1021  2016.06  [Refereed]

     View Summary

    We propose a novel Riemannian manifold preconditioning approach for the tensor completion problem with rank constraint. A novel Riemannian metric or inner product is proposed that exploits the least-squares structure of the cost function and takes into account the structured symmetry that exists in Tucker decomposition. The specific metric allows to use the versatile framework of Riemannian optimization on quotient manifolds to develop preconditioned nonlinear conjugate gradient and stochastic gradient descent algorithms in batch and online setups, respectively. Concrete matrix representations of various optimization-related ingredients are listed. Numerical comparisons suggest that our proposed algorithms robustly outperform state-of-the-art algorithms across different synthetic and real-world datasets.

  • Online Low-Rank Tensor Subspace Tracking from Incomplete Data by CP Decomposition using RLS

    Hiroyuki Kasai

    41st IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2016)     2519 - 2523  2016.03  [Refereed]

    DOI

  • Riemannian preconditioning for tensor completion

    Hiroyuki KASAI, Bamdev MISHRA

    8th NIPS workshop on optimization for machine learning (OPT2015)     0 - 0  2015.12  [Refereed]

  • Duration and Interval Hidden Markov Model for sequential data analysis

    Hiromi Narimatsu, Hiroyuki Kasai

    Proceedings of the International Joint Conference on Neural Networks   2015-   1 - 1  2015.09  [Refereed]

     View Summary

    Analysis of sequential event data has been recognized as one of the essential tools in data modeling and analysis field. In this paper, after the examination of its technical requirements and issues to model complex but practical situation, we propose a new sequential data model, dubbed Duration and Interval Hidden Markov Model (DI-HMM), that efficiently represents 'state duration' and 'state interval' of data events. This has significant implications to play an important role in representing practical time-series sequential data. This eventually provides an efficient and flexible sequential data retrieval. Numerical experiments on synthetic and real data demonstrate the efficiency and accuracy of the proposed DI-HMM.

    DOI

  • Riemannian preconditioning for tensor completion

    Hiroyuki KASAI, Bamdev MISHRA

    Workshop: Low-rank Optimization and Applications     0 - 0  2015.06  [Refereed]

  • Duration and Interval Hidden Markov Model for Sequential Data Analysis

    Hiromi Narimatsu, Hiroyuki Kasai

    2015 INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS (IJCNN)    2015  [Refereed]

     View Summary

    Analysis of sequential event data has been recognized as one of the essential tools in data modeling and analysis field. In this paper, after the examination of its technical requirements and issues to model complex but practical situation, we propose a new sequential data model, dubbed Duration and Interval Hidden Markov Model (DI-HMM), that efficiently represents "state duration" and "state interval" of data events. This has significant implications to play an important role in representing practical time-series sequential data. This eventually provides an efficient and flexible sequential data retrieval. Numerical experiments on synthetic and real data demonstrate the efficiency and accuracy of the proposed DI-HMM.

  • A Socialized System for Enabling the Extraction of Potential Values from Natural and Social Sensing

    Ryoichi Shinkuma, Yasuharu Sawada, Yusuke Omori, Kazuhiro Yamaguchi, Hiroyuki Kasai, Tatsuro Takahashi

    Modeling and Optimization in Science and Technologies   4   385 - 404  2015  [Refereed]

     View Summary

    This chapter tackles two problems we face when extracting values from sensing data: 1) it is hard for humans to understand raw/unprocessed sensing data and 2) it is inefficient in terms of management costs to keep all sensing data 'usable'. This chapter also discusses a solution, i.e., the socialized system, which encodes the characteristics of sensing data in relational graphs so as to extract values that originally contained the sensing data from the relational graphs. The system model, the encoding/decoding logic, and the real-dataset examples are presented. We also propose a content distribution paradigm built on the socialized system that is called SocialCast. SocialCast can achieve load balancing, low-retrieval latency, and privacy while distributing content using relational metrics produced from the relational graph of the socialized system. We did a simulation and present the results to demonstrate the effectiveness of this approach.

    DOI

  • Contextual mail (CXM): an e-mail system for enabling dynamic information-based destination control

    Yasuharu Sawada, Ryoichi Shinkuma, Tatsuro Takahashi, Hiroyuki Kasai, Kazuhiro Yamaguchi

    2014 IEEE 11TH CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC)    2014  [Refereed]

     View Summary

    There is a fact that, when people send messages, the destinations are not always deterministic; people sometimes want to send a message to someone who are just interested in the content of the message. However, e-mail services, which have been recognized as the de-facto standard for years, do not have such capability though a couple of emerging messaging applications like micro-blogging have it. Problems happen particularly when people use the e-mail system to make an announcement regarding an official event, which would be easily received even by people who are not likely interested in it. This paper proposes a new e-mail system that has the capability of dynamically controlling recipients of messages according to the context.

  • Lyric-based Automatic Music Image Generator for Music Browser Using Scene Knowledge

    Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   59 ( 3 ) 578 - 586  2013.08  [Refereed]

     View Summary

    This paper presents a proposal of a music image generator for users to grasp music easily and instantaneously on consumer electronics devices such as music players and smartphones. It provides users faster and more efficient music browsing functionality using a technique that automatically generates a music image that matches lyric contents. More specifically, a scene theme such as an event or place is extracted from lyrics using text mining techniques. A suitable music image is then created dynamically to match this extracted scene theme. This image generation is achieved by synthesizing multiple image materials to express the extracted scene theme flexibly. For choosing image materials, scene knowledge that has representative scene object compositions is proposed. Using this knowledge, the image synthesizer can select appropriate materials. Finally, the performance of the proposed automatic knowledge creation method is evaluated by comparison with manually created knowledge. Based on optimal parameters calculated in the evaluation, some examples of music images for well-known music lyrics are presented. In addition, the implemented system applying the proposed generator onto a server-side and a consumer-side consumer electronics device is also described.(1)

  • Time-slot Based Event-Driven Network Switch Control for Information Sharing in Multiple WLANs

    Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   59 ( 3 ) 521 - 529  2013.08  [Refereed]

     View Summary

    Recent wireless LAN technologies and service management technologies have produced widely diverse network services with no configuration task or effort for end-users' consumer electronics (CE) devices. This environment needs a mechanism that enables end-users to access services seamlessly across separated networks. To provide such accessibility, information for services in multiple networks should be available in each terminal that is currently connected to a wireless LAN. This paper presents a proposal of a new mechanism to collect and manage service information belonging to different WLANs autonomously for end-users. Specifically, an autonomous network switch and event-driven service information sharing scheme are proposed. The functionalities which are embedded on end-user CE devices require no central control device on a WLAN or the internet and require no modification of WLAN access points. The effectiveness of the proposal is demonstrated using simulation experiments. Future work is described(1).

    DOI

  • Development and Benchmarking of HTTP-based Multivision Video Server using Fast Stream Joiner

    Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   59 ( 2 ) 343 - 351  2013.05  [Refereed]

     View Summary

    High functionality and interactivity of video services are strongly desired. Earlier reports have presented an encoding scheme and a fast joining scheme for interactive multivision video streaming systems. Together, they enable numerous users to access any view area interactively at any desired resolution. The joining means the combination of multiple streams into a single video stream. The server joins pre-encoded multiple streams into one bitstream according to a user request; then the server transmits it simultaneously to many clients. This structure obviates complexity at the client terminal because the client terminal simply receives and decodes the single stream. This paper describes implementation of an actual HTTP-based streaming server by embedding the stream joiner module into a widely available HTTP server. The contribution of this paper is that the joining speed of the server surpasses the necessary speed attained with practical network equipment connecting to the server. Results of experiments described in this paper underscore the proposed method's effectiveness(1).

  • Embedded Middleware and Software Development Kit for Area-Based Distributed Mobile Cache System

    Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   59 ( 1 ) 281 - 289  2013.02  [Refereed]

     View Summary

    A new area-based distributed mobile cache system, a sustainable distributed Geocast technology, enables data caching temporarily in a designated local area using short-range communication technologies such as WiFi and Bluetooth. This system needs no infrastructure network and servers. This caching capability and mechanisms are expected to enhance short-range communications as a time-offset communication in a physical world. For that reason, it is sure to accelerate new location-based communication services. This paper reports a developed middleware for a widespread embedded operating system, and a software development kit with an open application programming interface. This middleware is expected to spur third-party developers to produce widely various applications using this proposed platform. Some pseudo-code is provided. Procedures to use this platform are also explained using an implemented geo-location social game(1).

  • Efficient Seamless Content Sharing Among Separate Multiple WLANs for Pervasive Mobile Network Environment

    Hiroyuki Kasai

    2013 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     210 - 211  2013  [Refereed]

     View Summary

    This paper presents a proposal of a scheme to collect and manage content and service data belonging to separate multiple WLANs so that Mobile CE devices can use them. Content and service list sharing for seamless multiple WLANs access by network switching is proposed. This paper shows the effectiveness of the proposed algorithm using simulations, and describes future work(1).

  • Music Classification Applying Prime Form and Interval-Class Vector

    Takashi Maekaku, Hiroyuki Kasai

    2013 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     312 - 313  2013  [Refereed]

     View Summary

    This paper proposes music classification considering melody transition for browsing system to recommend tunes depending on users' preference. Especially, we apply the Prime form and the Interval-Class Vector to Melodies Markov Model proposed in [1](1).

  • Development of HTTP-based Multivision Video Streaming Server and Benchmark Evaluation

    Yuuki Wakisaka, Hiroyuki Kasai

    2013 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     424 - 425  2013  [Refereed]

     View Summary

    High functionality and interactivity of video services are strongly desired. The authors have presented a proposal of an encoding scheme and a fast joining scheme for interactive multivision systems, where joining is the combination of multiple streams into a single video stream. This paper describes implementation of an actual HTTP-based streaming server by embedding the stream joiner module into a widely available HTTP server. The contribution of this paper is that the joining speed of the server surpasses the necessary speed attained with practical network equipment connecting to the server.

  • Embedded software development kit for sustainable distributed mobile Geocast

    Hiroyuki Kasai

    Digest of Technical Papers - IEEE International Conference on Consumer Electronics     524 - 525  2013  [Refereed]

     View Summary

    Our new distributed mobile cache system, a sustainable distributed Geocast technology, enables data caching temporarily in a designated local area. We released the open software development kit (SDK) for embedded systems. This paper explains details of the developed open SDK, an implementation guide, and three applications using this SDK1. © 2013 IEEE.

    DOI

  • Quantization parameter control at prediction restriction for fast multistream joiner in multi-vision system

    Naofumi Uchihara, Hiroyuki Kasai

    Digest of Technical Papers - IEEE International Conference on Consumer Electronics     141 - 142  2013  [Refereed]

     View Summary

    Multi-vision systems and panoramic video systems are expected to produce a new multimedia paradigm. Our previously presented multi-vision system allows many users to view multiple videos by virtue of fast stream joining algorithms. However image degradation occurs because these algorithms need restricted constant coding parameters. As described herein, we propose a QP control scheme to decrease this degradation without sacrificing high speed in the joiner. © 2013 IEEE.

    DOI

  • Selective Data Deactivation Mechanism in Sustainable Area-based Cache for Mobile Social Networks

    Hiromi Narimatsu, Hiroyuki Kasai

    MOBILE NETWORKS & APPLICATIONS   17 ( 6 ) 820 - 830  2012.12  [Refereed]

     View Summary

    This paper presents a proposal of a more resilient mechanism of an area-based sustainable cache system under a temporary decrease of the number of terminals. This mechanism suppresses interruptions of data relay and disappearances of cache data in the cache continually. The core technology enables each terminal to retain the received data in cache areas as "deactivated data" instead of deleting the data, even after a terminal leaves the area. Deactivated data are not relayed outside the target designated cache area. The data are reactivated and redistributed to others as relay data once the terminal revisits there. Consequently, the data are shared across time. Furthermore, particularly addressing the limitation of terminal storage, we proposed an adaptive scheme to select which data should be retained as deactivation data. This new mechanism leverages the proposed method under the storage limitation. As presented at the end of this paper, the simulation evaluations underscore the effectiveness of the proposed mechanism, and the adaptive selective scheme of deactivated data.

    DOI

  • Trigger Detection Using Geographical Relation Graph for Social Context Awareness

    Takayuki Nishio, Ryoichi Shinkuma, Francesco De Pellegrini, Hiroyuki Kasai, Kazuhiro Yamaguchi, Tatsuro Takahashi

    MOBILE NETWORKS & APPLICATIONS   17 ( 6 ) 831 - 840  2012.12  [Refereed]

     View Summary

    The concept of context awareness is believed to be a key enabler for the new ubiquitous network service paradigm brought by cloud computing platforms and smartphone OSs. In particular, autonomous context-based service customization is becoming an essential tool in this context because users cannot be expected to pick step by step the appropriate network services by manually and explicitly matching preferences for their current context. In this work, we hence focus on the core problem of how to detect changes of context for network services. In turn, detection of such changes can trigger timely system reconfigurations. We introduce a trigger detection mechanism based on a mixed graph-based representation model able to encode geographical and social relationships among people and social objects like stores, restaurants, and event spots. Our mechanism generates a trigger when a significant change in the graph takes place, and it is able to render significant changes in a geographical relationship that holds among objects socially connected with each other. The main benefits of our method are that (1) it does not require building reference models in advance, and (2) it can deal with different kinds of social objects uniformly once the graph is defined. A computer simulation scenario provides evidence on the expected performance of our method.

    DOI

  • Noise-Robust Environmental Sound Classification Method Based on Combination of ICA and MP Features

    Reona MOGI, Hiroyuki KASAI

    Sciedu Press, Artificial Intelligence Research   2 ( 1 ) 107 - 121  2012.12  [Refereed]

  • Quantization Parameter Control and Fast Code Modification for Fast Stream Joiner

    Naofumi Uchihara, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   58 ( 4 ) 1384 - 1392  2012.11  [Refereed]

     View Summary

    Multi-vision systems and panoramic video systems are expected to produce a new multimedia paradigm. However, their increased processing load on transmission servers handling large amounts of video and high-definition video must be considered. Our previously presented multi-vision system enables many users to view multiple videos by virtue of fast stream joining algorithms. The system joins (combines) much video stream on a transmission server into a single video stream. Then it transmits the joined single video stream to various client devices including mobile terminals. Because of its single-stream transmission, the client device enables decoding of the received video stream without special mechanisms. Especially, to join multiple video streams with high performance and without prediction inconsistency, the encoder fixes the number of a non-zero quantized coefficient (called TotalCoeff) to a certain in earlier work. Because this scheme of the fixing TotalCoeff in the encoder phase obviates the decoding process of each stream and modification of the prediction relation in the joining phase, it is possible to implement a stream joiner with a lightweight process. However, image degradation occurs because this scheme adds and drops the quantized coefficient. We emphasize that the amount of image degradation (called TotalCoeff fixing error or simply error) is dependent on the original TotalCoeff before fixing TotalCoeff and the Quantization Parameter (QP) because the quantization process has zero-rounding capability. Then we consider, using QP, the TotalCoeff estimation model and the error estimation model created by adding and deleting the coefficient. Under these models, we propose a QP control scheme to decrease this degradation without sacrificing high speed in the joiner(1).

  • Recognition of environmental sound recorded by mobile phone

    Reona MOGI, Hiroyuki KASAI

    ACM SIGMOBILE Mobile Computing and Communications Review   16 ( 4 ) 8 - 9  2012.10  [Refereed]

  • Implementation of distributed mobile storage and location-based message sharing among smart phones

    Hiroyuki KASAI

    ACM SIGMOBILE Mobile Computing and Communications Review   16 ( 4 ) 20 - 21  2012.10  [Refereed]

  • Sound-enhanced landscape album for smart-phone

    Hiroyuki KASAI, Satoshi INNAMI

    ACM SIGMOBILE Mobile Computing and Communications Review   16 ( 4 ) 22 - 23  2012.10  [Refereed]

  • NMF-based environmental sound source separation using time-variant gain features

    Satoshi Innami, Hiroyuki Kasai

    COMPUTERS & MATHEMATICS WITH APPLICATIONS   64 ( 5 ) 1333 - 1342  2012.09  [Refereed]

     View Summary

    Various environmental sounds exist around us in our daily life. Recently, environmental sound recognition has drawn great attention for understanding our environment. However, because environmental sounds derive from multiple sound sources, it is difficult to recognize them accurately. If we were able to separate sound sources before sound recognition as a pre-process, then recognition would be easier and more accurate. We assume that monaural microphones are widely installed in mobile devices used as recording devices. This paper therefore presents a proposal for monaural sound source separation of environmental sounds. Two-phase clustering using non-negative matrix factorization (NMF) is proposed to separate monaural sound sources. In this proposal, the time-variant gain feature is used as an attribute of an environmental sound for more efficient sound separation. (C) 2012 Elsevier Ltd. All rights reserved.

    DOI

  • Simple drift error-resilient H.264/AVC encoder for fast video transcoding using DCT coefficients

    Kwee-Li Cheng, Naofumi Uchihara, Hiroyuki Kasai

    COMPUTERS & MATHEMATICS WITH APPLICATIONS   64 ( 5 ) 1420 - 1430  2012.09  [Refereed]

     View Summary

    As described in this paper, an encoder that generates drift-error-resilient coded bitstreams is proposed. The proposed drift-error-resilient bitstreams are generated using the TotalCoeff or the total amount of non-zero DCT coefficients to estimate the drift-error distortion. This estimated drift error distortion is then examined in the motion estimation process. Results show that our proposed method can decrease drift error effectively compared to the original encoder and that it can achieve comparable PSNR to a conventional drift-error-resilient encoder. The main advantage of the proposed method compared to a conventional drift-error-resilient encoder is that, comparable PSNR performance, lower complexity and memory usage can be achieved without implementing an open-loop transcoder at the encoder feedback loop. (C) 2012 Elsevier Ltd. All rights reserved.

    DOI

  • H.264/AVC Encoding Control for Fast Stream Joiner in Interactive Multivision Video

    Naofumi Uchihara, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   58 ( 3 ) 1022 - 1030  2012.08  [Refereed]

     View Summary

    High functionality and interactivity of video services are strongly desired. This paper presents a proposal of an encoding scheme and a fast joining scheme for interactive multi-vision systems. The scheme enables numerous users to access any view area interactively with any desired resolution. The joining means the combination of multiple streams into a single video stream. The server joins pre-encoded multiple streams into one bitstream according to a user request, and then transmits it simultaneously to many clients. This structure obviates complexity at the client terminal because the client terminal simply receives and decodes the single stream. However, if joining processing loads are high, then it is difficult to provide services to many users. This paper presents a proposal of a new encoding method with prediction restrictions, MB-line size insertion, and Macro Block (MB) line byte alignment for a fast and lightweight stream joiner. Results of experiments described in this paper underscore the proposed method's effectiveness(1).

  • Music Relationship Visualization Based on Melody Piece Transition Using Conditional Divergence

    Takashi Maekaku, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   58 ( 3 ) 1006 - 1012  2012.08  [Refereed]

     View Summary

    This paper presents a proposal for music mapping considering melody piece transition for a browsing system to visualize mood distances among music. Especially, we use the Melodies Markov model proposed in an earlier report to calculate some Conditional Divergences and to express a music relationship on a 2-D map applying two dimension reduction methods: Principal Component Analysis and Hermitian Form Model. We also compare these combinations of distance measure and mapping method and analyze which is useful for visualization of the relevance among genres or the relevance among artists(1).

  • Simple Drift Error-resilient H.264/AVC Encoder for Fast Video Transcoding using DCT Coefficients

    Kwee-Li Cheng, Naofumi UCHIHARA, Hiroyuki KASAI

    Proc. of IEEE International Symposium on Computer, Consumer and Control 2012 (IS3C2012)   1  2012.06  [Refereed]

  • Environmental Sound Source Separation using Time-variant Gain Feature

    Satoshi INNAMI, Hiroyuki KASAI

    Proc. of IEEE International Symposium on Computer, Consumer and Control 2012 (IS3C2012)   1  2012.06  [Refereed]

  • Efficient H.264/AVC Software CAVLC Decoder based on Level Length Extraction

    Naofumi Uchihara, Hiroki Hayakawa, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   58 ( 1 ) 146 - 153  2012.02  [Refereed]

     View Summary

    This paper presents a proposal for an efficient software CAVLC decoder architecture in H.264/AVC based on level length extraction (LLE). Especially, level-decoding in a CAVLC decoder is addressed. Its features are summarized in two parts: higher efficient pipeline processing of level decoding, and simultaneous multiple calculations of multiple level codes separated from level decoding loop using Single Instruction Multiple data (SIMD) instruction. The former is achieved by separating Level calculation from Level parsing based on the LLE scheme, and removing branch operations in the level decoding loop. These improve the pipeline-processing efficiency. The latter removes Level calculation from the level decoding loop, and uses multiple Level calculations based on SIMD instruction. The proposed schemes emphasize the software architecture. They are therefore applicable to general computers. Consequently, they can also be integrated with other CAVLC opimization schemes for CoeffToken, TotalZeros, and RunBefore syntax elements. Based on results of evaluation experiments, we confirmed that the improved pipeline processing achieved 22% faster decoding speed compared with the conventional method, which used only the LLE scheme. The SIMD-based Level calculation also achieved a 38% faster decoder than before by integrating with the former part(1).

  • Implementation of Distributed Mobile Storage and Location-based Message Sharing Among Smart Phones (Demo)

    Hiroyuki KASAI, Reona MOGI

    ACM 13th Workshop on Mobile Computing Systems and Applications (HotMobile 2012)   1  2012.02  [Refereed]

  • Sound-enhanced Landscape Album for Smart-phone (Demo)

    Satoshi INNAMI, Reona MOGI, Hiroyuki KASAI

    Proc. of ACM 13th Workshop on Mobile Computing Systems and Applications (HotMobile 2012)   1  2012.02  [Refereed]

  • Recognition of Environmental Sound Recorded by Mobile Phone

    Reona MOGI, Satoshi INNAMI, Hiroyuki KASAI

    Proc. of ACM 13th Workshop on Mobile Computing Systems and Applications (HotMobile 2012)   1  2012.02  [Refereed]

  • Adaptive View-Area and Qality Scaling for Interactive Free View-Area Tile-based Multivision Video

    Naofumi Uchihara, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     141 - 142  2012  [Refereed]

     View Summary

    We have proposed so far a new multivision video provisioning scheme that enables numerous multiple users to access any view area with any desired resolution interactively and simultaneously. This paper proposes an adaptive view-area and quality scaling while preserving quick response for view-area movement. This can adaptively avoid redundant coding bits in conjunction with the movement of the viewing area. Simulation experiments and our implementation show the feasibility and effectiveness of our proposal.

  • Study of Visual Attention on Multiple Video Sequences

    Veraporn Watkanad, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     690 - 691  2012  [Refereed]

     View Summary

    As video technology advances rapidly, the need for simultaneous presentation of multiple videos is expected to increase in future. This paper utilized the orthogonal experiment to analyze visual effects of video physical features on multiple video sequences. The result shows that video position, human face, and motion attract attention effectively.

  • Music Relationship Visualization Based on Melody Transition Using Conditional Divergence for Music Browsing System

    Takashi Maekaku, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     43 - 44  2012  [Refereed]

     View Summary

    This paper proposes music mapping considering melody transition for browsing system to visualize mood distances among tunes. Especially, we use the Melodies Markov model proposed in [1] to calculate Conditional Divergence and express music relationship on 2-D map applying two Multi-dimensional Scaling (MDS) methods(1).

  • H.264/AVC Prediction Restriction Encoding Control for Fast Multiple Stream Joiner

    Naofumi Uchihara, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     277 - 278  2012  [Refereed]

     View Summary

    Recently, many researchers focus on high-definition and multivision video provisioning. [1] and [2] proposed a free-view access of the high-definition video and panoramic using multiple partitioned video streams. While they did not consider high complexity on the client to decode and play the video, [3] presented an innovative stream joining method for lower-complexity client as well as lower server load. It is, however, not practically feasible to serve videos simultaneously to a larger amount of users. This paper presents encoding techniques for a fast and simple stream joining that can achieve simultaneous multivision video provisioning.

  • Automatic Knowledge Construction of Scene Composition Using Object Categorization on Images

    Go Kikuchi, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     145 - 146  2012  [Refereed]

     View Summary

    This paper proposes a method to construct the scene composition of an event, a place and a situation by learning appearance pattern of objects in them. We recognize objects inside an image, and extract representative patterns based by analyzing the appearance combination of object in a large amount of images. Preliminary experiment shows that the proposal can create knowledge of scene composition with no contradiction and gives unfamiliar insights for the scene(1).

  • Lyrics-based Automatic Music Image Generation Using Scene Knowledge for Music Browsing

    Go Kikuchi, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     249 - 250  2012  [Refereed]

     View Summary

    Visual information of music makes users to understand it rapidly, and is very useful for a fast and efficient music browsing. In this paper, we propose an automatic music image generation that extracts features from lyrics such as an event and a place using the probabilistic parametric mixture model and the scene composition knowledge(1).

  • Implementation of Sound-enhanced Landscape Album Using Environmental Sound Provisioning System

    Satoshi Innami, Reona Mogi, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     47 - 48  2012  [Refereed]

     View Summary

    This paper presents an implementation of a location-based sound-enhanced landscape album. Users can enjoy scenery images in any designated location enhanced by environmental sound and a Life-like agent's comments. This system bases our environmental sound provisioning system, and newly proposes a hierarchical-structured sound composition scheme to achieve natural and inartificial sound. This system has been released to the public for smart-phone users(1).

  • Relational Metric: A New Metric for Network Service and In-network Resource Control

    Ryoichi Shinkuma, Hiroyuki Kasai, Kazuhiro Yamaguchi, Oscar Mayora

    2012 IEEE CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC)     352 - +  2012  [Refereed]

     View Summary

    This paper discusses a new paradigm of network service and in-network resource control: relational metric based control. The relational metrics indicate the closeness relationship between objects in the real world, and these objects could be people, locations, things, and content. Closeness is measured by using a fusion of online and physical sensing. We will describe the system model and discuss possible service applications of this technology.

  • Fast CAVLC Level Code Skip Scheme for H.264/AVC Stream Manipulation

    Naofumi Uchihara, Hiroki Hayakawa, Hiroyuki Kasai

    2012 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE)     267 - 268  2012  [Refereed]

     View Summary

    Fast scan and detection of the end of each CAVLC code is needed for bitstream operations like transcoding and manipulating. However, they need a larger computational load due to sequential and context-adaptive nature of CAVLC. That is why that it is dominant process in en entire decoding process. This paper proposes a fast skip scheme of CAVLC level code. Simulation results at the end of this paper show that the proposal about 70% reduction of CAVLC level code skip, and outperforms a conventional method.

  • Development of an efficient method for eye detection on mobile CE devices

    Ilya Lissoboi, Hiroyuki Kasai

    Proceedings - 2012 International Symposium on Computer, Consumer and Control, IS3C 2012     337 - 340  2012  [Refereed]

     View Summary

    In this paper the techniques for developing an efficient method of eye gesture tracking are explored. The goal is to verify the possibility of building an effective eye gesture input method relying on built-in hardware of the smart phone platform. The achieved results will be used as a basis for researching the technologies for gaze tracking on a mobile device. Effectiveness is measured according to detection accuracy, robustness, and processing performance. The results show limited success in achieving the stated goals, especially with respect to processing performance and provide a solid foundation for future work. © 2012 IEEE.

    DOI

  • Super-Realistic Environmental Sound Synthesizer for Location-based Sound Search System

    Satoshi Innami, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   57 ( 4 ) 1891 - 1898  2011.11  [Refereed]

     View Summary

    This paper presents a proposal of a super-realistic environmental sound synthesizer for a location-based sound search system. The location-based sound search system enables a user to experience any environmental sound in any desired remote place. This synthesizer is achieved by spatial audio mixing considering real-world conditions such as geographical features and townscapes, as well as dynamic situations such as those of town events and weather. Furthermore, a new velocity vector-based clustering method is proposed to reduce the cost of audio processing on the server side, which achieves a lower number of composing and decomposing clusters that have a direct and strong impact on high-cost audio processing such as spatial audio mixing(1).

  • Data Access Aggregation for Context-Aware Services on CE Portable Devices

    Hiromi Narimatsu, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   57 ( 4 ) 1978 - 1985  2011.11  [Refereed]

     View Summary

    With the promising development of user assist services on consumer electronics portable devices, service applications must continuously monitor dynamically changeable data and status, and judge whether their service actions should be activated. These operations, performed in real-time, result in heavy resource consumption on the portable devices. This paper proposes an innovative way to reduce the consumption by aggregating data access timings requested from multiple applications. Simulation shows that the proposed method can provide the highest precision data while reducing resource consumption. This mechanism can be installed into an operation system on a mobile device, or can operate as a middleware on the device. This must be one of key technologies to reduce battery power consumption of CE devices(1).

  • Fast H.264/AVC Stream Joiner for Interactive Free View-Area Multivision Video

    Naofumi Uchihara, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   57 ( 3 ) 1311 - 1319  2011.08  [Refereed]

     View Summary

    With the spread of high-definition video devices, and with the advance of digital broadcasting systems and video portal services in the Internet domains, numerous high-definition video presentations become available in everyday life. Under these circumstances, the desire of people to enjoy video contents in new ways had grown. This paper proposes a new multivision video provisioning system that enables numerous users to access any view area with any desired resolution interactively. The basic idea is that the partial area (tile)-based pre-coded video streams are stored in advance. These multiple streams are joined dynamically and delivered based on the user's view-area position. In this paper, the details of H.264/AVC tile-based video coding and a fast tile stream joiner scheme are presented. Simulation experiments and our practical implementation demonstrate the feasibility and effectiveness of our proposal.

  • Area-Based Collaborative Distributed Cache System using Consumer Electronics Mobile Device

    Hiromi Narimatsu, Hiroyuki Kasai, Ryoichi Shinkuma

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   57 ( 2 ) 564 - 573  2011.05  [Refereed]

     View Summary

    New communication services among nearby passing people are growing rapidly thanks to the advance of short-range wireless communication technologies and the widespread use of mobile devices that use them. Time-offset communication capability will engender a new service paradigm and promote new service emergence. This paper presents a proposal of a new distributed mobile cache system to cache data temporarily in a designated local area. The system is realized through collaborative consumer electronics mobile devices which use no infrastructure network. The system overview and its middleware on the mobile devices are explained. Furthermore, new relay data algorithms are proposed to provide lower-overhead communication and a more robust caching capability. Finally, results of simulation experiments underscore the effectiveness of the proposed control algorithm in terms of the communication cost and the length of the cache time(1).

  • Analysis of Drift-Error Propagation in H.264/AVC Transcoder for Variable Bitrate Streaming System

    Kwee-Li Cheng, Naofumi Uchihara, Hiroyuki Kasai

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   57 ( 2 ) 888 - 896  2011.05  [Refereed]

     View Summary

    Video transcoding is one of the most essential technologies in consumer electronics server and gateway products for a variable bitrate video streaming system. Especially, for a real-time streaming system, drift-error resilient coded bitstreams that do not require high complexity transcoding processes are desired. For the generation of drift-error resilient coded bitstreams at the encoder side, an investigation on the drift-error propagation characteristic in H.264/AVC by applying different motion compensation (MC) precisions are carried out in this paper. The results show that the drift-error propagation in half-pixel MC precision increases due to the usage of six-tap filter. For quarter-pixel MC precision, the drift-error propagation decreases. Besides that, we found out that the requantization parameter and MC precision only affects the amount of error in the requantized frame but amount of error propagation depends on the MC precision and sequence of the pixel value. It is also found that drift-error propagation ratio is defined at some point regardless of MC precisions(1).

  • Fast Stream Joiner for Next-Generation Interactive Video

    Naofumi Uchihara, Hiroyuki Kasai

    IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE 2011)     319 - 320  2011  [Refereed]

     View Summary

    This paper presents a proposal of a new video provisioning scheme that enables numerous multiple users to access any view area with any desired resolution interactively. The basis is that the tile-based encoded multiple streams are joined dynamically and delivered based on the user's view-area position. This paper details a tile-based video coding scheme and a fast tile stream joiner scheme. Simulation experiments and our practical implementation illustrate the feasibility and effectiveness of our proposed scheme.

  • Resource Access Aggregation for Mobile CE Device

    Hiromi Narimatsu, Hiroyuki Kasai

    IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE 2011)     575 - 576  2011  [Refereed]

     View Summary

    This paper proposes an innovative way to reduce the consumption by aggregating resource accesses timings requested from multiple applications. The simulation shows that the proposed method can provide the highest precision information while keeping the resource consumption lower.

  • Location-Based Distributed Mobile Storage Using Short-Range Wireless Communication

    Hiromi Narimatsu, Hiroyuki Kasai, Ryoichi Shinkuma

    IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE 2011)     237 - +  2011  [Refereed]

     View Summary

    This paper proposes a new distributed mobile storage architecture to store information in a local area by collaborating end-terminals without an infrastructure network. This paper shows the effectiveness of the proposed control algorithm by the simulation experiment.

  • Analysis of Drift-Error Propagation in H.264/AVC Video Transcoding

    Kwee-Li Cheng, Naofumi Uchihara, Hiroyuki Kasai

    IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE 2011)     321 - 322  2011  [Refereed]

     View Summary

    In this paper, for the generation of drift-error-resilient coded bitstreams at the encoder side, an investigation on the drift-error propagation in H.264 by applying different motion estimation precisions is carried out. The results show that the drift-error propagation in half-pixel motion estimation precision increases due to the usage of six-tap filter. Mathematical model for estimating drift-error propagation is presented as well.

  • On-Demand Soundscape Generation Using Spatial Audio Mixing

    Satoshi Innami, Hiroyuki Kasai

    IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS (ICCE 2011)     29 - 30  2011  [Refereed]

     View Summary

    This paper proposes an on-demand soundscape generation and provisioning for a user to experience a real world in a requested remote place. This generation is achieved by spatial audio mixing considering a real world condition like geographical features or townscapes as well as dynamic situation such as town events or weather. The proposed velocity vector-based clustering can reduce the cost of composing/decomposing clusters of many sound sources.

  • Demand prediction based on social context for mobile content services

    Hiroyuki Kubo, Ryoichi Shinkuma, Tatsuro Takahashi, Hiroyuki Kasai, Kazuhiro Yamaguchi, Roy Yates

    IEEE International Conference on Communications     1 - 5  2011  [Refereed]

     View Summary

    The recent enhancement of mobile devices and wireless networks has enabled content services in mobile environments. Demand prediction is a traditional but powerful technique used for content services. However, it is hard to predict local demand in mobile environments because it depends not only on just user preference and the popularity of common content but also on other factors
    users request content related to their locations
    moreover, they are interested in the content uploaded by their friends who visited the location before them. Thus, we need to consider the context with multiple factors affecting the demand. In addition, we also need to consider the sequence of contexts.We call a sequence of contexts social context. This makes it difficult to predict local demand from users. In this paper, we propose a novel demand prediction engine that extracts local demand depending on social context and estimates what content will be requested there. To extract the demand, we use a log database and a pattern-matching technique in our prediction engine. To validate our prediction engine, we apply a prefetching service using the engine to a mobile content service. © 2011 IEEE.

    DOI

  • Extraction of Hidden Common Interests between People Using New Social-graph Representation

    Kazufumi Yogo, Akihiro Kida, Ryoichi Shinkuma, Tatsuro Takahashi, Hiroyuki Kasai, Kazuhiro Yamaguchi

    2011 20TH INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS (ICCCN)     1 - 6  2011  [Refereed]

     View Summary

    It can be essential in the new-generation content services to predict the potential demands of people, which they themselves have not recognized or cannot express precisely. Social graphs representing the relationships between people are used for predicting demand in current Internet-based services. However, these graphs cannot represent the relationships of two users residing in common communities or common places. We propose representing not only a person but also things like communities and social events together as a single node in a social graph. This representation allows us to estimate who shares potential interests with a given person. We evaluated the estimation accuracy of our representation using an actual relational dataset from an academic database. Results show that our representation can estimate if two people share common interests that cannot be found with conventional methods that only use human nodes for estimation, and it can estimate the relations without using human nodes.

  • Asynchronous Prefetching Streaming for Quick-Scene Access in Mobile Video Delivery

    Naofumi Uchihara, Hiroyuki Kasai, Yoshihiro Suzuki, Yoshihisa Nishigori

    IEEE TRANSACTIONS ON CONSUMER ELECTRONICS   56 ( 2 ) 633 - 641  2010.05  [Refereed]

     View Summary

    This paper proposes a new video delivery system with a lightweight, smooth, and quick-response accessibility to video scenes without interference by unstable mobile network conditions and also without consuming mobile device storage. This can avoid a video scene access delay brought on by mobile-network-specific delay and instability. We proposed an innovative streaming technology that consists of a view-context-aware asynchronous prefetching and streaming scheme and a seamless media assembly and media synchronization scheme. As an additional powerful extension for this system, we present a hierarchical prefetching asynchronous streaming technology that considers a video-scene structure. This can provide access to a general view through the whole content as well as to a detailed view around playback position by consideration of the video-scene structure and the user's viewing position. The implementation details on mobile phones and preliminary evaluation results are described, and its feasibility is also shown(1).

    DOI

  • Hierarchical Pre-fetching Mechanism for Mobile Video Streaming based on Video Scene Structure

    Naofumi Uchihara, Hiroyuki Kasai, Yusuke Yano, Yoshihiro Suzuki

    2010 DIGEST OF TECHNICAL PAPERS INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS ICCE    2010  [Refereed]

     View Summary

    An efficient mobile video delivery with a light-weight, smooth and quick-responsible accessibility to video scenes has been proposed. This can avoid a content access delay brought by mobile-network-specific delay and instability. As an additional extension for our previous proposal, we present an innovative efficient access scheme with a hierarchical pre-fetching asynchronous streaming technology considering video scene structure. This can provide an access to a general view through a whole content as well as a detail view around a playback position by considering video scene structure and user's viewing position. The implementation details on mobile phones are also described at the end of this paper.

  • Data access aggregation for context-aware services on CE portable devices

    Hiromi NARIMATSU, Hiroyuki KASAI

    Proc. of IEEE 9th International Symposium on Consumer Electronics 2011 (ISCE2009)     922 - 926  2009.07  [Refereed]

  • Efficient resource access algorithm for context-aware user assist services on portable devices

    Hiromi Narimatsu, Hiroyuki Kasai

    Digest of Technical Papers - IEEE International Conference on Consumer Electronics     922 - 926  2009  [Refereed]

     View Summary

    With the promising user assist services on portable devices, service controllers in multiple applications must continuously monitor dynamically changeable data and status, and judge whether its service action should be activated. These operations in a real-time manner bring heavy resource consumption on the portable devices. This paper proposes an innovative way to reduce the consumption by aggregating resource accesses timings requested from multiple applications. The simulation shows that the proposed method can provide the highest precision information while keeping the resource consumption lower. ©2009 IEEE.

    DOI

  • Efficient Resource Access Algorithm for Context-Aware User Assist Services on Portable Devices

    Hiromi Narimatsu, Hiroyuki Kasai

    ISCE: 2009 IEEE 13TH INTERNATIONAL SYMPOSIUM ON CONSUMER ELECTRONICS, VOLS 1 AND 2     927 - 931  2009  [Refereed]

     View Summary

    With the promising user assist services on portable devices, service controllers in multiple applications must continuously monitor dynamically changeable data and status, and judge whether its service action should be activated. These operations in a real-time manner bring heavy resource consumption on the portable devices. This paper proposes an innovative way to reduce the consumption by aggregating resource accesses timings requested from multiple applications. The simulation shows that the proposed method can provide the highest precision information while keeping the resource consumption lower.

  • Mobile Video System based on Pre-Download and NW Streaming Coordination

    Hiroyuki KASAI, Naofumi UCHIHARA

    ACM 9th Workshop on Mobile Computing Systems and Applications (HotMobile 2008)   2008  2008.02  [Refereed]

  • Quick Accessible Mobile Video System based on Pre-downloading, Pre-fetching and Streaming Technologies

    Hiroyuki Kasai, Naofumi Uchihara

    2008 IEEE 19TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS   2008   1980 - 1984  2008  [Refereed]

     View Summary

    A light-weight, smooth, and quick-responsible accessibility to contents are truly needed for a practical usage of the mobile video services. We research on and develop a new innovative mobile video technology, which utilizes pre-download, pre-fetching and asynchronous network streaming schemes. This paper describes its innovative mechanisms, especially an asynchronous streaming technique and an asynchronous thumbnail data pre-fetching technique. Two prototype implementations of mobile video client are described in detail, and performance evaluations are given at the end of this paper.

  • Mobile Video AJAX Technology for Time-Directional Quick Access

    Hiroyuki Kasai, Naofumi Uchihara

    2008 IEEE INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATION SYSTEMS (ISWCS 2008)   2008   413 - 417  2008  [Refereed]

     View Summary

    Innovative Ajax-like functionality in a mobile video delivery system is introduced, where light-weight, smooth, and quick-responsible accessibility to contents can be provided. This technology consists of viewers' view context aware asynchronous pre-fetching and streaming scheme, and seamless media assembly and media synchronization scheme. This paper describes its innovative mechanisms and elemental technologies in detail. A prototype implementation of a mobile video client is described in detail, and performance evaluations are given at the end of this paper.

  • A service provisioning system for distributed personalization with private data protection

    Hiroyuki Kasai, Wataru Uchida, Shoji Kurakake

    JOURNAL OF SYSTEMS AND SOFTWARE   80 ( 12 ) 2025 - 2038  2007.12  [Refereed]

     View Summary

    Personalized services can provide significant user benefits since they adapt their behavior to better support the user. Personalized services use a variety of data related to the user to decide their behavior. Thus personalized service needs a provisioning system that can collect the data that impacts service behavior and allows selection of the most appropriate service. However, in the coming ubiquitous environment, some data necessary for determining service behavior might be unavailable due to two possible reasons. One is that the data does not exit. The other is that the data exists but cannot be accessed. For example, users do not want to disclose their personal information, and service providers do not also want to expose data related to their knowhow in services. This paper describes a new service provisioning system for distributed personalization with private data protection. Specifically, the system selects applicable services by assessing how well each candidate service behaves when some data is missing. It then executes those selected services while hiding the users' and providers' private data in a distributed manner. We first summarize the requirements for a personalized service system, and introduce our fundamental policies for the system. The two main components of our system are then described in detail. One component is a service assessment mechanism that can judge if a service can work without data that can be used for adaptation. The second component is a service execution mechanism that can utilize private data while still ensuring privacy. This component divides service logic and executes divided logic where necessary data is available. The paper finally describes our prototype implementation and its performance evaluation results. (C) 2007 Elsevier Inc. All rights reserved.

    DOI

  • Scalable Execution Control Method for Context-Dependent Services

    Wataru UCHIDA, Hiroyuki KASAI, Shoji KURAKAKE

    IEICE Transactions on Information and Systems, D   90-D ( 6 ) 1403 - 1416  2007.06  [Refereed]

  • Notification Control System for Mobile Terminal Considering User Situation(Ubiquitous Computing,<Special Issue>Interaction Technologies : From Principles to Applications)

    Hiroyuki KASAI, Shoji KURAKAKE

    IPSJ Transactions   48 ( 3 ) 1393 - 1404  2007.03  [Refereed]

  • A scalable execution control method for context-dependent services

    Wataru Uchida, Hiroyuki Kasai, Shoji Kurakake

    INTERNATIONAL CONFERENCE ON PERVASIVE SERVICES, PROCEEDINGS     121 - +  2006  [Refereed]

     View Summary

    We propose a scalable service execution control method for a service that is triggered when the context satisfies an execution condition. We call such services context-dependent. A context-dependent service needs to monitor the context that affects the execution condition all the time. The proposed method tremendously reduces the cost of context monitoring operations while it surely executes appropriate services when their execution conditions are satisfied.
    Our method assumes that there are a lot of terminals monitoring contexts and a server that collects context information. from the terminals to manage service executions for a large number of services. Each context is modeled by a probabilistic time series, and thus, the probability that an execution condition is satisfied can be calculated at a given tine. The time at which the execution condition is likely to be satisfied is anticipated, and the server instructs relevant terminals to monitor contexts and to send their values to it before the anticipated execution. The time to collect context values is decided by the server; which considers the effect of the statistical variance of each context on the probability of satisfying the execution condition. Moreover, each terminal monitors its context and notifies the server when its value is out of the designated range, even if this occurs before the time set by the server. The range of values is set by the server: We conducted simulation experiments that showed the effectiveness of the proposed method.

  • A service provisioning system for distributed personalization with private data protection

    Hiroyuki Kasai, Wataru Uchida, Shoji Kurakake

    INTERNATIONAL CONFERENCE ON PERVASIVE SERVICES, PROCEEDINGS     163 - +  2006  [Refereed]

     View Summary

    Personalized services can provide significant user benefits since they adapt their behavior to better support the user. Personalized services use a variety of data related to the user to decide their behavior. Thus personalized service needs a provisioning system that can collect the data that impacts service behavior and allows selection of the most appropriate service. However, in the coming ubiquitous environment, some data necessary for determining service behavior might be unavailable due to two possible reasons. One is that the data does not exit. The other is that the data exists but can not be accessed. For example, users do not want to disclose their personal information, and service providers do not also want to expose data related to their know-how in services.
    This paper describes a new service provisioning system for distributed personalization with private data protection. Specifically, the system selects applicable services by assessing how well each candidate service behaves when some data is missing. It then executes those selected services while hiding the users' and providers' private data in a distributed manner. We first summarize the requirements for a personalized service system, and introduce our fundamental policies for the system. The two main components of our system are then described in detail. One component is a service assessment mechanism that can judge if a service can work without data that can be used for adaptation. The second component is a service execution mechanism that can utilize private data while still ensuring privacy. This component divides service logic and executes divided logic where necessary data is available. The paper finally describes our prototype implementation and its performance evaluation results.

  • A service provisioning system for distributed personalization with private data protection

    Hiroyuki Kasai, Wataru Uchida, Shoji Kurakake

    INTERNATIONAL CONFERENCE ON PERVASIVE SERVICES, PROCEEDINGS   80 ( 12 ) 163 - +  2006  [Refereed]

     View Summary

    Personalized services can provide significant user benefits since they adapt their behavior to better support the user. Personalized services use a variety of data related to the user to decide their behavior. Thus personalized service needs a provisioning system that can collect the data that impacts service behavior and allows selection of the most appropriate service. However, in the coming ubiquitous environment, some data necessary for determining service behavior might be unavailable due to two possible reasons. One is that the data does not exit. The other is that the data exists but can not be accessed. For example, users do not want to disclose their personal information, and service providers do not also want to expose data related to their know-how in services.
    This paper describes a new service provisioning system for distributed personalization with private data protection. Specifically, the system selects applicable services by assessing how well each candidate service behaves when some data is missing. It then executes those selected services while hiding the users' and providers' private data in a distributed manner. We first summarize the requirements for a personalized service system, and introduce our fundamental policies for the system. The two main components of our system are then described in detail. One component is a service assessment mechanism that can judge if a service can work without data that can be used for adaptation. The second component is a service execution mechanism that can utilize private data while still ensuring privacy. This component divides service logic and executes divided logic where necessary data is available. The paper finally describes our prototype implementation and its performance evaluation results.

  • Multiple bitrate output transcoder based on requantizer and reencoder sharing

    Isao Nagayoshi, Hiroyuki Kasai, Tsuyoshi Hanamura, Hideyoshi Tominaga

    Electronics and Communications in Japan, Part I: Communications (English translation of Denshi Tsushin Gakkai Ronbunshi)   88 ( 2 ) 21 - 33  2005.02  [Refereed]

     View Summary

    This paper proposes a video transcoder that realizes efficiently the function of multirate conversion to multiple hitrates. The multirate conversion function is realized as follows. The decoder and the inverse quantizer are shared as a single processor. The requantizer and the reencoder with the same requantization step are shared among outputs. With these provisions, an architecture is proposed whereby the processing complexity in multirate conversion can be reduced. The number of requantization processing operations per macro-block is examined theoretically, and it is shown that the conversion processing complexity can be formulated as a function of the output bitrate. Lastly, the theoretical evaluation and the evaluation experiment based on these investigations show that the sharing of the requantizer/reencoder is the scheme that reduces the increase of the processing complexity as a function of the number of outputs, and can cope with any number of outputs with two to four times the processing complexity of the single-rate output scheme. © 2004 Wiley Periodicals, Inc.

    DOI

  • Adaptive notification system guaranteeing message reachability

    H Kasai, K Yamazaki, S Kurakake

    INTERNATIONAL CONFERENCE ON PERVASIVE SERVICES 2005, PROCEEDINGS     208 - 217  2005  [Refereed]

     View Summary

    A variety of information communication devices have been developed to help people maintain his/her awareness of interesting information. Notification systems play an important role in delivering up-to-date, important information via such devices. We have been developing a novel push-style notification system that delivers a succession of new messages onto the mobile terminal display in a well-timed manner. This system increases the probability of the user discovering interesting information from among a stream of items shown one after another, and accessing the network to get more details if desired. Needless to say, the appropriateness of the message to he notified is important to the user. To make a push-style notification system more useful and comfortable for users, however, it is also essential to deliver the information without interrupting the user's on-going task. Furthermore, some mechanism that can recover from the user's failure to notice a message is also needed. We fold all these abilities into the one term of "Message Reachability", and propose a comprehensive and flexible push-style notification system. One of its main features is a Bayesian "Notification User Model" which takes task state, user state and user characteristic into consideration. The other is an adaptive notification control mechanism based on the user model, and a compensation mechanism to handle messages that the user missed. This paper details the user model and message control mechanisms, and concludes by showing implementation details.

  • Privacy preserving ubiquitous service provisioning based on Bayesian network conversion

    Hiroyuki Kasai, Wataru Uchida, Shoji Kurakake

    2005 WORKSHOP OF THE 1ST INTL CONFERENCE ON SECURITY AND PRIVACY FOR EMERGING AREAS IN COMMUNICATION NETWORKS - SECURECOMM     73 - 82  2005  [Refereed]

     View Summary

    Protecting personal privacy is already seen as a crucial requirement in the implementation of service provisioning in the ubiquitous environment. From the view point of preserving personal privacy, the simplest approach would be for users not to reveal any kind of private information at any time while keeping the number of available services unrestricted. Meanwhile, from the service provider's point of view, though this has been not clearly stated so far, their service logics should also be hidden from others because those logics may leak their know-how. This paper presents a novel ubiquitous service provisioning mechanism that gives more opportunities for users to get available services while preserving the secrecy of users' and providers' sensitive information. The basic idea of this mechanism is to share service execution procedures between the service provider and the user by exchanging converted service logic described in the form of Bayesian decision networks. This paper describes the proposed mechanism and the conversion algorithm for the Bayesian networks, and details the system architecture and implementation.

  • A Proposal for Expanding 4G Networking Towards the Ubiquitous World

    Kazuo IMAI, Hiroshi NAKAMURA, Kennichi YAMAZAKI, Wataru TAKITA, Hiroyuki KASAI

    Proc. of 19th World Telecommunications Congress (WTC 2004)     1  2004  [Refereed]

  • Multiple Bitrate Output Transcoder Based on Re-quantizer and Re-encoder Sharing

    Isao NAGAYOSHI, Hiroyuki KASAI, Tsuyoshi HANAMURA, Hideyohi TOMINAGA

    IEICE Transactions on Communications, B   86-B ( 12 ) 2511 - 2521  2003.12  [Refereed]

  • Scalable Gateway Based on Stream Switching with Multiple Transcoder

    Hiroyuki KASAI, Hideyoshi TOMINAGA

    IEICE Transactions on Communications, B   86-B ( 8 ) 2229 - 2244  2003.08  [Refereed]

  • Seamless Service Environment Platform for Service Transfer among Terminals

    Hiroyuki KASAI, Yoko KIKUTA, Norihiro KAWASAKI, Kenichi YAMAZAKI

    IEICE Transactions on Communications, B   86-B ( 8 ) 1389 - 1403  2003.08  [Refereed]

  • Seamless/Ubiquitous Service Support

    Kenichi YAMAZAKI, Hiroyuki KASAI, Yoko KIKUTA, Norihiro KAWASAKI, Tsutomu YOKOYAMA

    NTT DoCoMo Technical Journal   10 ( 4 ) 24 - 28  2003.04  [Refereed]

  • Video scalability rate control method by dynamic controlling of hierarchical bit allocation ratio

    Hiroyuki Kasai, Mei Kodama, Hideyoshi Tominaga

    Electronics and Communications in Japan, Part I: Communications (English translation of Denshi Tsushin Gakkai Ronbunshi)   86 ( 1 ) 83 - 96  2003.01  [Refereed]

     View Summary

    This paper considers the hierarchical video coding system, and proposes a bit allocation rate control method by dynamic control of the hierarchical bit allocation ratio. As the first step, the MPEG-2 SNR scalability method is considered as the hierarchical video coding, and the relation between the hierarchical bit allocation and the basic/enhancement layer quality is analyzed. It is shown that the intermediate bit allocation ratio may degrade greatly the quality in the enhancement layer. The dependency of the image quality on the hierarchical bit allocation is noted, and video coding bit allocation control is proposed, where the hierarchical loss can be suppressed by dynamically controlling the bit allocation ratio for each picture. A control method is proposed particularly, where the optimal bit allocation ratio is calculated so that the characteristic function is maximized under the constraint that the bit allocation ratio for each GOP is kept constant. Lastly, a simulation experiment is presented. It is shown that the hierarchical loss, which is generated in the conventional bit allocation control, can be suppressed by the proposed control method, and the effectiveness of the proposed method is demonstrated.

    DOI

  • Remultiplexing scheme for MPEG-2 multiprogram transport stream transcoder

    T Takahashi, T Hanamura, H Kasai, Nagayoshi, I, H Tominaga

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS   86 ( 2 ) 1 - 13  2003  [Refereed]

     View Summary

    In this paper, we propose an output packet remultiplexing scheme for an MPEG-2 multiprogram transport stream transcoder. The proposed scheme avoids STD buffer failure by dividing the packets into Program Specific Information (PSI), audio, and video and implementing remultiplexing. Specifically, PSI packets are multiplexed at a constant time interval, audio packets are multiplexed at the same times as the input times of the audio TS packets, and video packets are multiplexed so that the outputs of the video TS packets are at equal intervals. Finally, we clearly demonstrate through simulation experiments the ability to prevent STD buffer failure and the effectiveness of the proposed scheme. (C) 2002 Wiley Periodicals, Inc.

    DOI

  • Design of Seamless Service Environment for Adaptive Service Transfer among Terminals

    Yoko KIKUTA, Hiroyuki KASAI, Norihiro KAWASAKI, Kennichi YAMAZAKI

    Proc. of 8th International Workshop on Mobile Multimedia Communications (MoMuC 2003)   2003  2003  [Refereed]

  • The development of a multimedia transcoding system for mobile access to video conferencing

    H Kasai, M Nilsson, T Jebb, M Whybray, H Tominaga

    IEICE TRANSACTIONS ON COMMUNICATIONS   E85B ( 10 ) 2171 - 2181  2002.10

     View Summary

    Today, many audiovisual delivery systems, including video streaming and video conferencing, are being developed for use over a range of networking technologies, the differing characteristics of which pose problems for service level interoperability. Multimedia transcoding is one means to provide interoperability between different types of audiovisual terminals and between terminals that connect to different networks. In this paper, we will present a multimedia transcoder system, which provides interoperability between video conferencing terminals on IP networks and mobile terminals on mobile networks.

  • Quantization Parameter Control Scheme for MPEG-2 Video Transcoder

    Hiroyuki KASAI, Isao NAGAYOSHI, Tsuyoshi HANAMURA, Wataru KANEYAMA, Hideyoshi TOMINAGA

    IEICE Transactions on Communications, B   85-B ( 2 ) 278 - 287  2002.02  [Refereed]

  • Re-multiplexing Scheme for MPEG-2 Multi-Program Transport Stream Transcoder

    Takeshi TAKAHASHI, Tsuyoshi HANAMURA, Hiroyuki KASAI, Isao NAGAYOSHI, Hideyoshi TOMINAGA

    IEICE Transactions on Communications, B   85-B ( 2 ) 299 - 311  2002.02  [Refereed]

  • Packet-multiplexing scheme in MPEG-2 multi-program transport stream transcoder

    Takeshi Takahashi, Hiroyuki Kasai, Tsuyoshi Hanamura, Hideyoshi Tominaga

    ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings   4   4178  2002  [Refereed]

     View Summary

    As an appliance that achieves rate reduction of MPEG-2 multi-program transport streams, MPEG-2 multi-program transport stream transcoder has been proposed. This transcoder needs to multiplex packets without any STD buffer failure. However, no efficient packet-multiplexing scheme has been reported until now. In this paper, we propose packet-multiplexing scheme that no STD buffer failure occurs in MPEG-2 multi-program transport stream transcoder. This proposed scheme is implemented by the following ways: 1) PSI packets are output in constant interval, 2) audio packets are output in the same PCR as that of input transport stream, 3) video packets are output so that the intervals of each output packet for every video elementary stream should be constant. From simulation experiments, we show the status of STD buffer and show the effectiveness for our proposed scheme.

    DOI

  • Scalable Coding Algorithm by Separating and Merging of MPEG-2 Bitstream

    Isao NAGAYOSHI, Tsuyoshi HANAMURA, Hiroyuki KASAI, Hideyoshi TOMINAGA

    IEICE Transactions on Information and Systems, D-II   84-D-II ( 12 ) 2525 - 2544  2001.12  [Refereed]

  • A Study on Re-quantization Parameter Control Scheme for MPEG-2 Video Transcoder

    Isao NAGAYOSHI, Hiroyuki KASAI, Tsuyoshi HANAMURA, Wataru KANEYAMA, Hideyoshi TOMINAGA

    ITE Journal   55 ( 12 ) 1669 - 1674  2001.12  [Refereed]

  • Video Rate Control Scheme for MPEG-2 Multi-Program TS Transcoder

    Hiroyuki KASAI, Maki SUGIURA, Wataru KAMEYAMA, Hideyoshi TOMINAGA

    IEICE Transactions on Communications, B   84-B ( 10 ) 1877 - 1889  2001.10  [Refereed]

  • A Study on the Scalable Coding Algorithm by Separating and Merging of MPEG-2 Bitstream

    Isao NAGAYOSHI, Tsuyoshi HANAMURA, Hiroyuki KASAI, Hideyoshi TOMINAGA

    Proc. of 11th International Packet Video Workshop PV-2001   M   1 - 7  2001  [Refereed]

  • Scalable video transmission by separating and merging of MPEG-2 bitstream

    Isao Nagayoshi, Tsuyoshi Hanamura, Hiroyuki Kasai, Hideyoshi Tominaga

    Proceedings - IEEE International Conference on Multimedia and Expo   TA   16 - 19  2001  [Refereed]

     View Summary

    In this paper, we propose a scalable video transmission system based on transcoding. First, we focus on the transcoder to reduce the bitrate of MPEG-2 bitstreams. We show that it is realized the layered coding by using the differential data between input and output of a transcoder. Next, we show the coding algorithm of this differential data. This algorithm can improve the coding efficiency by removing unnecessary code for differential data. By simulation experiments, we show that the proposed coding algorithm prevents the loss of coding efficiency in traditional hierachical coding, and show the effectiveness of proposed scheme.

    DOI

  • The implementation of an audiovisual transcoding system

    H. Kasai, M. Nilsson

    Proceedings - IEEE International Conference on Multimedia and Expo   FA0   357 - 360  2001  [Refereed]

     View Summary

    Multimedia transcoding technology can provide interoperability between different types of audiovisual terminals and between terminals that connect to different networks. This paper describes a flexible multimedia transcoder that enables service interoperability between different types of terminals across heterogeneous networks.

    DOI

  • Rate Control Scheme for Low Delay MPEG - 2 Video Transcoder

    Hiroyuki KASAI, Tsuyoshi HANAMURA, Wataru KAMEYAMA, Hideyoshi TOMINAGA

    IEICE Transactions on Communications, B   83-B ( 2 ) 151 - 164  2000.02  [Refereed]

  • Rate Control Method in MPEG Bitstream Bitrare Scaling Considering

    Hiroyuki KASAI, Isao NAGAYOSHI, Wataru KAMEYAMA, Hideyoshi TOMINAGA

    IEICE Transactions on Information and Systems, D-II   83-D-II ( 2 ) 509 - 524  2000.02  [Refereed]

  • Rate control scheme for low-delay MPEG-2 video transcoder

    Hiroyuki Kasai, Maki Sugiura, Tsuyoshi Hanamura, Wataru Kamayama, Hideyoshi Tominaga

    IEEE International Conference on Image Processing   1   964 - 967  2000  [Refereed]

     View Summary

    In this paper, we focus on the video transcoder as a bit rate reducer in a network node and propose a rate control scheme for a low-delay MPEG-2[1] video transcoder. First, we summarize the requirements of a rate control algorithm for low delay transcoding. Next, based on these requirements, we describe the proposed rate control scheme in detail. Then, we analyze the input and output buffer delay and calculate the total delay time of the proposed transcoder. Finally, we evaluate the proposed scheme from the simulation results of experiments on picture quality, transcoding delay time and GOP (Group Of Pictures) structure information (N/M value) of the input bit stream. Consequently, we showed that the proposed scheme can provide the same picture quality as a traditional scheme and is independent of the GOP structure.

    DOI

  • Rate control scheme for low-delay MPEG-2 video transcoder

    H Kasai, M Sugiura, T Hanamura, W Kameyama, H Tominaga

    VISUAL COMMUNICATIONS AND IMAGE PROCESSING 2000, PTS 1-3   4067   473 - 484  2000  [Refereed]

     View Summary

    In this paper, we focus on the video transcoder as a bit rate reducer in a network node and propose a rate control scheme for a low-delay MPEG-2(1) video transcoder. First, we summarize the requirements of a rate control algorithm for low-delay transcoding. Next, based on these requirements, we describe the proposed rate control scheme in detail. Then, we analyze the input and output buffer delay and calculate the total delay time of the proposed transcoder. Finally, we evaluate the proposed scheme from the simulation results of experiments on picture quality, transcoding delay time and GOP (Group Of Pictures) structure information (N/M value) of the input bit stream. Consequently, we showed that the proposed scheme can provide the same picture quality as a traditional scheme and is independent of the GOP structure.

  • Rate control scheme for MPEG transcoder considering drift-error propagation

    Nagayoshi, I, H Kasai, H Tominaga

    VISUAL COMMUNICATIONS AND IMAGE PROCESSING 2000, PTS 1-3   4067   485 - 496  2000  [Refereed]

     View Summary

    As the transform method of video bit stream to the required bit stream format, the video transcoder has been adopted in various applications. In this paper, we focus on a MPEG video transcoder that can reduce the required bit rate by using re-quantization in the DCT domain. Furthermore, we propose a rate control method for this MPEG video transcoder that takes into consideration the estimation of drift-error propagation. First, we show the transcoder architecture with calculation of "Drift-Error Propagation Ratio". Next, we explain the proposed rate control method that uses minimization of the sum of re-quantization Error and drift-error. Finally, from simulation experiments, me compare the proposed rate control method to the traditional rate control method in terms of complexity, required buffer size and picture quality.

  • Video Scalability Rate Control Method by Dynamic Controlling Bits Allocation Ratio

    Hiroyuki KASAI, Mei KODAMA, Hideyoshi TOMINAGA

    Proc. of European Signal Processing Conference (EUSIPCO 2000)     161  2000  [Refereed]

  • Rate control scheme for low-delay MPEG-2 video transcoder

    H Kasai, M Sugiura, T Hanamura, W Kameyama, H Tominaga

    VISUAL COMMUNICATIONS AND IMAGE PROCESSING 2000, PTS 1-3   4067 ( 1 ) 473 - 484  2000  [Refereed]

     View Summary

    In this paper, we focus on the video transcoder as a bit rate reducer in a network node and propose a rate control scheme for a low-delay MPEG-2(1) video transcoder. First, we summarize the requirements of a rate control algorithm for low-delay transcoding. Next, based on these requirements, we describe the proposed rate control scheme in detail. Then, we analyze the input and output buffer delay and calculate the total delay time of the proposed transcoder. Finally, we evaluate the proposed scheme from the simulation results of experiments on picture quality, transcoding delay time and GOP (Group Of Pictures) structure information (N/M value) of the input bit stream. Consequently, we showed that the proposed scheme can provide the same picture quality as a traditional scheme and is independent of the GOP structure.

  • A study on the rate control method for MPEG transcoder considering drift-error propagation

    Nagayoshi, I, H Kasai, H Tominaga

    2000 INTERNATIONAL CONFERENCE ON IMAGE PROCESSING, VOL I, PROCEEDINGS   ( 1 ) 960 - 963  2000  [Refereed]

     View Summary

    As the transform method of video bit stream to the required bit stream format, the video transcoder has been adopted in various applications. In this paper, we focus on a MPEG video transcoder that carl reduce the required lit rate by using re-quantization in the DCT domain. Furthermore, we propose a rate control method for this MPEG video transcoder that takes into consideration the estimation of drift-error propagation. Next, from simulation experiments, we compare the proposed rate control method to the traditional rate control method in terms of complexity, required buffer size and picture quality.

  • Video Scalability Rate Control Method by Dynamic Controlling of Hierarchical Bits Allocation Ratio

    Hiroyuki KASAI, Mei KODAMA, Hideyoshi TOMINAGA

    IEICE Transactions on Communications, B   82-B ( 8 ) 1475 - 1488  1999.08  [Refereed]

  • The Hierarchical Image Coding and its Video Data Description Methods in Multimedia Scalability Packages

    Mei KODAMA, Hiroyuki KASAI, Hideyoshi TOMINAGA

    Proc. of Picture Coding Symposium (PCS99)     37 - 40  1999.04  [Refereed]

  • A study on the hybrid image coding and structuring methods for multimedia scalability packages communication services

    M Kodama, H Kasai, H Tominaga

    IEEE INTERNATIONAL CONFERENCE ON MULTIMEDIA COMPUTING AND SYSTEMS, PROCEEDINGS VOL 2   2   92 - 96  1999

     View Summary

    Multimedia communication services based on standard information, such as MPEG-1, MPEG-2, H.261 and H.263, had been indicated using multimedia scalability packages, which can provide multimedia information according to functionality and availability for users. In this paper, we propose the coding method of video information architecture in these packages, which are called "MSP". The MSP data architecture is defined using hierarchical architectures. We especially considered temporal feature information. The temporal scalability concept is described by both of MSP data and scalability content data. And then, as coding schemes, we attention to video hybrid scalability using spatial scalability and temporal one and scalability profiles are shown. Finally, we explained the new video temporal function by MSP data description.

  • A Consideration on the Efficiency of Image Scalability from Coding Bits Allocation

    Hiroyuki KASAI, Mei KODAMA, Hideyoshi TOMINAGA

    Proc. of Picture Coding Symposium (PCS97)     441 - 444  1997.09  [Refereed]

  • Local Area High Resolution Image Scalability based on Visual Characteristics

    Mei KODAMA, Hiroyuki KASAI, Kyoji MAEDA, Hideyoshi TOMINAGA

    Proc. of Picture Coding Symposium (PCS96)     299 - 302  1996.03  [Refereed]

  • A Visual Information Model with Hierarchical Image Coding

    Hiroyuki KASAI, Mei KODAMA, Kyoji MAEDA, Hideyoshi TOMINAGA

    Proc. of Multimedia Japan '96     102 - 105  1996  [Refereed]

▼display all

Misc

  • System Design for Estimating Social Relationships from Sensing Data

    Akihiro Kida, Ryoichi Shinkuma, Tatsuro Takahashi, Hiroyuki Kasai, Kazuhiro Yamaguchi, Oscar Mayora

    2013 IEEE 27TH INTERNATIONAL CONFERENCE ON ADVANCED INFORMATION NETWORKING AND APPLICATIONS WORKSHOPS (WAINA)     27 - 32  2013  [Refereed]

     View Summary

    As the number of network services provided in fixed and mobile environments are increasing recently, it becomes harder to expect users to manually pick up appropriate services from all these available. Therefore, it has been proposed that network services are automatically selected in accordance with relational information among people and other social objects, i.e., locations, things and contents. The fusion of online and physical sensing platforms has brought about the possibility of building relational information from sensing data: online logs and sensing data collected at mobile devices could reflect what objects people are related to in their daily lives. The relational information can be represented as a graph in which each node could be a social object and each link could represent a direct relation between two nodes and is called relational metric. We discuss how to build relational metrics from sensing data and propose a system design for it.

    DOI

  • Data Sharing Control Method for Location-Based Collaborative Mobile Storage

    NARIMATSU Hiromi, KASAI Hiroyuki, SHINKUMA Ryoichi, YAMAGUCHI Kazuhiro

    ITE Technical Report   35 ( 7 ) 15 - 18  2011.02

     View Summary

    We have so far proposed a new distributed mobile storage architecture to store data in a designated local area. This is achieved by collaborated end-terminals without an infrastructure network. In this paper, new relay data algorithms are proposed to bring a lower overhead communication and a more robust storage capability. Simulation experiments show the effectiveness of the proposed control algorithm from the communication cost and the length of storage time.

    CiNii

Industrial Property Rights

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  • COMMUNICATION TERMINAL, CONTENT REPRODUCTION METHOD, CONTENT REPRODUCTION PROGRAM, CONTENT REPRODUCTION SYSTEM, AND SERVER THEREFOR

    Patent

  • 通信端末、コンテンツ再生方法,プログラム,コンテンツ再生システム及びサーバ

    Patent

  • Information Notification System and Information Notification Method

    Patent

  • Information notification system and information notification method

    Patent

  • 商品情報配信システム、コンテンツ配信サーバ、ユーザ端末、視聴履歴管理サーバ、視聴情報検索サーバ、商品情報検索サーバ及び商品情報配信方法

    4866747

    Patent

  • 商品情報配信システム、コンテンツ配信サーバ、ユーザ端末、視聴履歴管理サーバ、視聴情報検索サーバ、商品情報検索サーバ及び商品情報配信方法

    Patent

  • 配信システム、口コミ情報管理サーバ、配信サーバ、ユーザ端末及び配信方法

    Patent

  • ネットワークサーバ及び制御方法

    Patent

  • 情報収集制御装置及び情報収集制御方法

    4680804

    Patent

  • 情報収集制御装置、サービス提供システム及び情報収集制御方法

    4856984

    Patent

  • サービス選択システム及びサービス選択方法

    Patent

  • 情報収集制御装置及び情報収集制御方法

    Patent

  • 情報収集制御装置及び情報収集制御方法

    4584803

    Patent

  • ネットワーク変換システム, ネットワーク変換方法

    Patent

  • サービス決定装置及びサービス決定方法

    Patent

  • サービス提供サーバ装置、端末装置、及び、これらの制御方法

    4652869

    Patent

  • 情報再通知システム, 端末装置, 情報再通知方法

    Patent

  • サービス提供サーバ装置、端末装置、バインドサーバ装置、及び、これらの制御方法

    Patent

  • 注視状態検出装置および注視状態推定方法

    Patent

  • Information notification system and information notification method

    Patent

  • 通知用ユーザ状態管理装置, 通知制御装置, 情報通知装置および情報通知システム並びに情報通知方法

    4954467

    Patent

  • Information notification system and information notification method

    Patent

  • サービス制御装置及びサービス制御方法

    Patent

  • Bit stream separating and merging system, apparatus, method and computer program product

    Patent

  • タイミング決定装置及びタイミング決定方法

    4776179

    Patent

  • Timing decision apparatus and timing decision method

    US7610395

    Patent

  • Timing decision apparatus and timing decision method

    Patent

  • サービス移動試験装置, 及び, サービス移動試験方法

    Patent

  • サービス中断復元システム、サービス中断復元方法、通信端末、サービス中断復元装置及びサービス中断復元プログラム

    4058308

    Patent

  • サービス中断復元システム, サービス中断復元方法, 通信端末, サービス中断復元装置及びサービス中断復元プログラム

    Patent

  • Suspened service recovery system, suspended service recovery method, terminal suspended service recovery apparatus and computer program product

    Patent

  • Suspended service recovery system, method and computer program product

    Patent

  • 符号化信号分離・合成装置, 符号化信号分離・合成方法および符号化信号分離・合成プログラムを記録した媒体

    Patent

  • デジタル情報配信システム, コンテンツ変換サーバ, 携帯端末, ホームサーバおよびこれらの制御方法, 並びに, これらの制御プログラムを記録した媒体

    Patent

  • Bit stream separating and merging system, apparatus, method and computer program product

    US6901109

    Patent

  • Bitstream separating and merging system, apparatus, method and computer program product

    Patent

  • マルチプログラム圧縮符号化信号変換方法, 装置および変換プログラムを記録した媒体

    Patent

  • 符号化信号分離・合成装置, 差分符号化信号生成装置, 符号化信号分離・合成方法, 差分符号化信号生成方法, 符号化信号分離・合成プログラムを記録した媒体および差分符号化信号生成プログラムを記録した媒体

    3561485

    Patent

  • Coded signal separating and merging apparatus, method and computer program product

    Patent

  • Separating and merging of MPEG-2 coded bitstream

    Patent

  • Apparatus, method and computer program product for transcoding a coded multiplexed sound and moving picture sequence

    US6654421

    Patent

  • Apparatus, method and computer program product for transcoding a coded multiplexed sound and moving picture sequence

    US6654421

    Patent

  • 多重化音響・動画圧縮符号化信号変換方法, 装置および変換プログラムを記録した媒体

    Patent

  • Apparatus, method and computer program product for transcoding a coded multiplex sound and moving pictuture sequence

    Patent

  • 動画像圧縮符号化信号変換方法, 装置および変換プログラムを記録した媒体

    Patent

  • 動画像圧縮符号化信号変換方法, 装置および変換プログラムを記録した媒体

    Patent

  • 動画像圧縮符号化制御方法および動画像圧縮符号化装置

    Patent

  • 動画像圧縮符号化信号変換方法および装置

    Patent

  • Apparatus, method and computer program product for transcoding a coded moving picture sequence

    Patent

  • スケーラビリティを有する画像符号伝送装置および方法並びに再量子化方法

    Patent

  • スキップマクロブロック禁止制御方法, スキップマクロブロック禁止制御装置およびスキップマクロブロック禁止制御プログラムを記録した媒体

    Patent

  • Apparatus, method and computer program product for transcoding a coded moving picture sequence

    US6587508

    Patent

  • 動画像圧縮符号化信号変換方法, 装置および変換プログラムを記録した媒体

    2001-169283,2001-169283

    Patent

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Awards

  • 電子情報通信学会 モバイルネットワークと アプリケーション 研究会 (MoNA) 年間最優秀発表賞

    2016.08   電子情報通信学会 モバイルネットワークと アプリケーション 研究会 (MoNA)  

  • 電気通信普及財団賞 テレコムシステム技術賞

    2015.03   The Telecommunications Advancement Foundation  

  • IEEE ICCE (International Conference on Consumer Electronics) Best Paper Award (Storage Technology Category)

    2011.01   IEEE Consumer Electronics Society   US

  • IEICE Service Recognution Award

    2010.09   IEICE Communication Society  

  • Yamashita Memorial Award, 2003

    2003.07   Information Processing Society of Japan (IPSJ),  

  • Ericsson Young Scientist Award 2001

    2001.11   Ericsson  

  • Niwa Outstanding Paper Award

    2001.03   Niwa Memorial  

  • Ando Incentive Prize for the Study of Electronics

    2000.07   The Foundation of ANDO Laboratory  

  • 早稲田大学大川功記念論文賞

    2000.03   早稲田大学  

  • INOSE Incentive Prize for the Study

    1996.07   財団法人 電気電子情報学術振興財団  

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Research Projects

  • 実空間ナレッジが求められる時代の新たなデータ重要度による通信制御

    Project Year :

    2017.04
    -
    2020.03
     

  • 高次元大規模信号デ ータ処理のためのス ケーラブル・リーマン 多様体最適化とその 応用

    Project Year :

    2016.04
    -
    2019.03
     

    Hiroyuki KASAI

  • 超多数ユーザへの同 時提供のための高効 率高機能映像符号結 合方式とメディア間 連携方式

    Project Year :

    2013.04
    -
    2016.03
     

    Hiroyuki KASAI

  • マイクロナレッジと そのアプリケーショ ンの研究開発

    Ministry of Internal Affairs and Communications  Strategic Information and Communications R&D Promotion Programme

    Project Year :

    2015
    -
    2016
     

    Ryoichi SHINKUMA

  • 関係性メトリックに基づく新世代ネットワークアプリケーション

    National Institute of Information and Communications Technology  新世代ネットワークを支えるネットワーク仮想化基盤技術の研究開発

    Project Year :

    2012
    -
    2016
     

    Ryoichi SHINKUMA

  • インタラクティブマルチビジョン映像提供のための圧縮符号結合方式とメディア間連携方式

    The Okawa Foundation  研究助成

    Project Year :

    2014
     
     
     

    Hiroyuki KASAI

  • ソーシャルメトリックに基づく統合アーキテクチャ

    National Institute of Information and Communications Technology  新世代ネットワーク技術戦略の実現に向けた萌芽的研究

    Project Year :

    2011
    -
    2012
     

    Ryoichi SHINKUMA

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Presentations

  • Tensor learning on preconditioned Tucker manifold and application to tensor regression of spatiotemporal forecasting problem

    Hiroyuki KASAI, Bamdev MISHRA

    IEICE Technical Report MoNA2017-56 

    Presentation date: 2018.01

  • A study on stochastic variance reduced multiplicative update for nonnegative matrix factorization

    Hiroyuki Kasai

    電子情報通信学会 ニューロコンピューティング研究会(NC)信学技報(NC2017-31) 

    Presentation date: 2017.11

  • Joint dimensionality reduction and dictionary learning on symmetric positive definite matrices

    Hiroyuki Kasai

    情報処理学会オーディオビジュアル複合情報処理研究会(AVM) 

    Presentation date: 2017.10

  • Riemannian stochastic variance reduced gradient for large-scale data applications

    Hiroyuki Sato, Hiroyuki KASAI, Bamdev MISHRA

    IEICE Society Conference 

    Presentation date: 2016.09

  • Stochastic low-rank tensor completion: a Riemannian manifold preconditioning approach

    Hiroyuki KASAI, Bamdev MISHRA

    IEICE Society Conference 

    Presentation date: 2016.09

  • Riemannian gossip algorithms for decentralized matrix completion

    Bamdev MISHRA, Hiroyuki KASAI

    IEICE Society Conference 

    Presentation date: 2016.09

  • Riemannian Stochastic Variance Reduced Gradient and its Convergence Analysis

    Hiroyuki Sato, Hiroyuki KASAI, Bamdev MISHRA

    日本オペレーションズ・リサーチ学会 2016年秋季研究発表会 

    Presentation date: 2016.09

  • SVRG 法のグラスマン多様体上への拡張とその行列補完問題への応用

    佐藤 寛之, 笠井 裕之, Bamdev MISHRA

    日本応用数理学会 2016年度 年会 

    Presentation date: 2016.09

  • Riemannian stochastic variance reduced gradient on Grassmann manifold

    Hiroyuki KASAI, Hiroyuki Sato, Bamdev MISHRA

    Fifteenth FIT 2016 

    Presentation date: 2016.09

  • リーマン多様体最適化に基づく低ランク行列・テンソル補完とその周辺 ~計量チューニング,確率的勾配法,分散最適化~

    Hiroyuki KASAI, Bamdev MISHRA

    Japanese Joint Statistical Meeting 2016 

    Presentation date: 2016.09

  • Riemannian stochastic variance reduced gradient and its applications to machine learning

    Hiroyuki Sato, Hiroyuki KASAI, Bamdev MISHRA

    Japanese Joint Statistical Meeting 2016 

    Presentation date: 2016.09

  • Stochastic low-rank tensor completion: a Riemannian manifold preconditioning approach

    Hiroyuki KASAI, Bamdev MISHRA

    Japanese Joint Statistical Meeting 2016 

    Presentation date: 2016.09

  • Geometry of Tucker tensor manifold with Riemannian metric tuning and its application to large-scale machine learning

    Hiroyuki Kasai, Bamdev Mishra

    情報処理学会オーディオビジュアル複合情報処理研究会(AVM) 

    Presentation date: 2016.09

  • リーマン計量調整に基づく Tucker 多様体の幾何の提案と最適化問題への応用

    Hiroyuki KASAI, Bamdev MISHRA

    京都大学 数理解析研究所 研究集会「最適化技法の最先端と今後の展開」 

    Presentation date: 2016.08

  • 直交制約つき最適化問題に対するリーマン多様体上の確率的分散縮小勾配法

    佐藤寛之, 笠井 裕之, Bamdev MISHRA

    京都大学 数理解析研究所 研究集会「最適化技法の最先端と今後の展開」 

    Presentation date: 2016.08

  • Riemannian stochastic variance reduced gradient for large-scale machine learning

    Hiroyuki KASAI, Hiroyuki Sato, Bamdev MISHRA

    IEICE Technical Report MoNA2016-11 

    Presentation date: 2016.08

  • Online Low-Rank Tensor Subspace Tracking from Incomplete Data by CP Decomposition using RLS

    Hiroyuki KASAI

    IEICE Annual Conference 

    Presentation date: 2016.03

  • Riemannian preconditioning for tensor completion

    Hiroyuki KASAI, Bamdev Mishra

    IEICE Annual Conference 

    Presentation date: 2016.03

  • Riemannian preconditioning for tensor completion

    Hiroyuki KASAI, Bamdev MISHRA

    The 78th National Convention of IPSJ 

    Presentation date: 2016.03

  • Riemannian preconditioning for tensor completion

    Hiroyuki KASAI, Bamdev MISHRA

    IEICE Technical Report MoNA2015-50 

    Presentation date: 2016.01

  • Riemannian preconditioning for tensor completion

    Hiroyuki KASAI, Bamdev MISHRA

    計測自動制御学会 第8回コンピューテーショナル・インテリジェンス研究会 

    Presentation date: 2015.12

  • Riemannian preconditioning for tensor completion

    Hiroyuki KASAI, Bamdev MISHRA

    情報論的学習理論ワークショップ(IBIS) 

    Presentation date: 2015.11

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Syllabus

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Teaching Experience

  • アナログ回路実験

    The University of Electro-Communications  

  • アナログ回路実験

    電気通信大学  

  • アナログ回路実験

    The University of Electro-Communications  

  • アナログ回路実験

    電気通信大学  

  • データ解析最適化論

    The University of Electro-Communications  

  • データ解析最適化論

    電気通信大学  

  • 数値解析およびプログラミング演習

    The University of Electro-Communications  

  • 数値解析およびプログラミング演習

    電気通信大学  

  • データ解析最適化論

    The University of Electro-Communications  

  • データ解析最適化論

    電気通信大学  

  • 数値解析およびプログラミング演習

    The University of Electro-Communications  

  • 数値解析およびプログラミング演習

    電気通信大学  

  • 数値解析およびプログラミング演習

    The University of Electro-Communications  

  • 数値解析およびプログラミング演習

    電気通信大学  

  • データ解析最適化論

    The University of Electro-Communications  

  • データ解析最適化論

    電気通信大学  

  • データ解析最適化論

    The University of Electro-Communications  

  • データ解析最適化論

    電気通信大学  

  • 応用ネットワーキング論2

    The University of Electro-Communications  

  • 応用ネットワーキング論2

    電気通信大学  

  • 応用ネットワーキング論2

    The University of Electro-Communications  

  • 応用ネットワーキング論2

    電気通信大学  

  • 応用ネットワーキング論2

    The University of Electro-Communications  

  • 応用ネットワーキング論2

    電気通信大学  

  • 応用ネットワーキング論2

    The University of Electro-Communications  

  • 応用ネットワーキング論2

    電気通信大学  

  • 応用ネットワーキング論2

    The University of Electro-Communications  

  • 応用ネットワーキング論2

    電気通信大学  

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