Updated on 2024/04/16


SAKAI, Shigekazu
Faculty of Science and Engineering
Job title
Professor Emeritus

Research Experience

  • 2014.04

    Waseda University   Faculty of Science and Engineering

  • 2001.04

    Waseda University   School of Global Information and Telecommunication Studies   professor

  • 1994.04

    Kyushu Institute of Design

Education Background

  • 1975.04

    Tokyo Institute of Technology  

Research Areas

  • Database   Digital Archives

Research Interests

  • Digital Image Expression

  • SAR

  • digital content

  • digital art

  • visualization

  • computer animation

  • computer graphics

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  • A Fundamental Study on Water Content Comparison in Phenolic Foam Columns by using Microwave Backscattering Measurement

    ALGNEAER Fahad, SUGANUMA Mutsumi, IWATA Shinya, SAKAI Shigekazu, NOHMI Hitoshi, NOHMI Akira

    Journal of The Remote Sensing Society of Japan   38 ( 2 ) 174 - 188  2018

     View Summary

    <p>The ability to measure the amount of water dispersed inside a solid object is highly desirable in a number of fields such as agriculture, forestry, and civil engineering. In this study, the authors' goal was to measure the water content inside phenolic foam columns using only microwave backscattering measurements by a scatterometer developed for airborne synthetic aperture radar (SAR). The experiment was carried out in an anechoic chamber using scatterometers three frequency bands: L, X, and Ku. The column irradiated with microwaves was a cylinder of phenolic foam capable of holding various volumes of water. Four objects with a different volume of water permeating were irradiated by microwaves, and the backscattering was measured. In consideration of the influence of microwave fading, the columns were placed on a turntable and rotated one revolution (i.e., 360°) while taking about 75,000 continuous measurements of the entire surface. The measurements were then evaluated based on variance and median. As a result of measuring the microwave backscattering, it was found that the higher the water content in the column, the higher the radar cross-section (RCS) median, average, and maximum values for that object in all three bands. Regarding the L band, it was clearly shown that it was possible to distinguish when the volume content of water was 25 % and 50 %. Also, when the water content of the column was relatively small, the range of dispersion was large, and when the water content exceeded a certain value, the dispersion widths began to converge. This indicates the possibility that analyzing the variance of the microwave backscattering may be a clue to knowing the dispersion state of the water content of the object. In this experiment, the microwave backscattering was continuously measured while rotating the object one time, and a statistical method was used to analyze the results. This measurement method is new, and it could add a new approach to measuring moisture content noninvasively.</p>


  • Effectiveness of Detailed Information and Material Information for CG Reproduction of Historic Buildings

    内藤旭惠, 内藤旭惠, 重藤祐紀, 堀川華波, 岡本哲志, 坂井滋和

    画像電子学会誌(CD-ROM)   46 ( 2 ) 336‐344 - 344  2017.04

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    This research is to reveal what kind of information is effective for more precise reproduction of digitally archived historic buildings. This research examines two CG Computer Graphics reproduction projects of Mitsubishi Ichigokan (Marunouchi, Chiyoda-Ku, Tokyo), which has already been demolished and digitally reproduced; and The Clinical Research Building, the University of Tokyo Hospital (Hongo, Bunkyo-Ku, Tokyo), which still remains with its demolition scheduled soon. While for the former subject, we only had its drawing for design, photos, reference materials, and hearings with the person in charge of an architectural design office, which reconstructed the building, we were able to study the actual building for the latter, collecting the necessary information in addition to its drawing for design and photos. Our research leads to finding that the vital element for more precise CG reproduction is Detail Information and Material Information. This paper illustrates the information that would be effective in advanced CG reproduction, describing and contrasting the working details for both buildings.

    CiNii J-GLOBAL

  • Present States of Preservation of Historical Buildings and Reproduction by Using Computer Graphics

    内藤旭惠, 重藤祐紀, 坂井滋和, 岡本哲志

    情報文化学会誌   23 ( 2 ) 51‐58 - 58  2016.12

    CiNii J-GLOBAL

  • Real-Time Line Drawing Using Image Processing and Deforming Process Together in 3DCG

    奥屋武志, 田中克明, 坂井滋和

    芸術科学会論文誌(Web)   15 ( 2 ) 75‐85 (WEB ONLY)  2016.06


  • Expression Technique of Semi‐Transparent Process of Human using Interpolating Background Method in a Human Image

    奥屋武志, 奥屋大樹, 藪野健, 坂井滋和

    芸術科学会論文誌(Web)   14 ( 6 ) 264‐272 (WEB ONLY) - 146  2015.12

     View Summary

    When trying to display semi-transparent only human in human images, the processing of background covered with human becomes a problem. In this study, we have developed a method to express images of semi-transparent human without discomfort by generating background image from background around human and adding gloss.

    CiNii J-GLOBAL

  • An investigation into encouraging higher user self-disclosure during text-based computer mediated communication: A case study of prompter communication system

    Li Jen Chen, Mutsumi Suganuma, Shigekazu Sakai, Jun Ohya, Shunichi Yonemura, Yukio Tokunaga

    Journal of the Institute of Image Electronics Engineers of Japan   42   89 - 101  2013.01

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    An investigation into encouraging higher user self-disclosure during text-based Computer Mediated Communication (CMC) system known as the Prompter Communication system (PCS), proposed by Yonemura et al. in previous studies, in which 1 to 3 black circular prompter images ("•") are embedded onto the background of a text-field canvas as stimuli and as an embryonic basis for conversation, have been investigated and evaluated. The effects on supporting the projection or reflection of generated mental representations onto messages with the "•" prompter image as part of the representations within the message contents have also been examined. During the investigation, the concepts and features of the Geneplore cognitive creative thinking process model, together with self-projections, were integrated into the proposed system. Based on these concepts and features, the PCS aims to encourage users to express their mental representations by projecting or reflecting them onto the messages in combination with the provided "•" prompter image as part of the message contents. Communication experiments using the prototype PCS system have been conducted, where a Normal Communication System, NCS which uses only a plain text-field canvas without the "•" prompter image, is compared with the PCS. The experimental results indicate that communication conducted using the PCS results in an increased number of messages with the "•" prompter image(s) involved as part of the message contents than as background images. Further analysis into the self-disclosure level of the message contents and the relationships between the degree of self-disclosure and the representations of the "•" prompter image(s) within the messages have indicated that the degrees of self-disclosure increases when the "•" prompter image(s) are used to represent the participant him/herself, or the participant's thoughts and emotions, and decreases when the "•" prompter image(s) are used to represent animals or objects, or when the "•" prompter image(s) presented within the messages have been ignored. Investigations into the differences in self-disclosure level between message contents from both the PCS and the NCS have shown that using the PCS results in a generally higher degree in the average frequency of the appearance of high self-disclosure information than when using the NCS. During the conversation, these messages contain information with a high level of self-disclosure, which, consequently, may further lead to the development of intimate and deep interpersonal relationships.


  • 視線一致型及び従来型TV会議システムを利用した2大学間遠隔交流学習

    谷田貝雅典, 永岡慶三, 坂井滋和, 安田孝美

    情報文化学会誌   18 ( 1 ) 34 - 41  2011.07

     View Summary

    In this research, it connects between Waseda University and Okazaki Women's Junior College by using video conferencing system, and the exchange learning was executed in the following three features: an eye-contact type distance environment, the former type (without eye contact) distance environment and a face-to-face environment. In this paper, the content of the exchange learning that consists of the composition of three stages executed for three years between two universities is reviewed, evaluated, and the following result is discussed. As a result of covariance structural analysis on result of questionnaire surveys in exchange learning, it has been understood to approximate eye-contact type distance environment to face-to-face environment, the effect of face-to-face environment or more was achieved in the debate study. Because there is a study environment difference in without eye contact distance environment, the satisfaction to study decreases, it was clarified that teaching method that supplemented this was necessary.

    CiNii J-GLOBAL

  • 視線一致型および従来型テレビ会議システムを利用した遠隔授業と対面授業によるディベート学習の教育効果測定

    谷田貝雅典, 坂井滋和, 永岡慶三, 安田孝

    教育システム情報学会誌   28 ( 2 ) 129 - 140  2011.04

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    <p>In distance education, there is no precedent for research of debate that can be eye contact. In this research, 5 learning environments, the eye-contact type and former (non-eye-contact) type systems of distance learning through Video Conferencing System (screen size 15 and 30 inches), and the real (face-to-face) class, were compared. Number of remarks, effective remarks and learning behavior factor were acquired from each class, and analysis of variance, covariance structure analysis was executed. As a result, in the number of effective remarks, there is no difference between eye-contact type and the real class, and it has decreased in former type. In eye-contact type and the real class, the learned behavior that raises learning effects most is "verbal communications". In former type, the decrease in the learning effect by "getting tired, relaxation" is remarkable. The strategy that draws out "verbal communications", "non-verbal communications", "attention of eye" amplification of screen size, is necessary to control the decrease in the learning effect.</p>


  • 視線一致型および従来型テレビ会議システムを利用した遠隔授業と対面授業における学習者特性に応じた学習効果の共分散構造分析

    谷田貝雅典, 坂井滋和, 永岡慶三, 安田孝美

    教育システム情報学会誌   27 ( 3 ) 254 - 266  2010.09

     View Summary

    <p>This research aimed to clarify the difference of learning effect according to learner's property by distance learning using eye-contact type, conventional non-eye-contact type video conferencing systems and the real class by facing. The learner's property was obtained beforehand, learning behavior factor and the learning effect was obtained from each class. As a learning model by simultaneous lecture, the recursive model was assumed, covariance structure analysis was executed. As a result, the following have been understood. At the real class, the learner with high "grounding" raises the learning effect. At the conventional type, the learner with high "maladaptive tendency" and "superiority complex" lower the learning effect. At the eye-contact type, the learner with high "extroversion" raises the learning effect, while the learner with high "insensitivity" lower the learning effect.</p>


  • 観察姿勢の変化が画像の認識に及ぼす影響についての基礎的検討

    菅沼睦, 坂井滋和

    ヒューマンインタフェースシンポジウム論文集(CD-ROM)   2009   ROMBUNNO.3144  2009.09


  • Corporate Activity Varying with Internet


    技報安川電機   70 ( 3 ) 108 - 115  2006.11


  • Analysis of Education Effect among Eye-Contactable or Former-Type of Distance Learning through Video Conferencing Systems and Face-to-Face Learning

    YATAGAI Masanori, SAKAI Shigekazu

    Japan Journal of Educational Technology   30 ( 2 ) 69 - 78  2006.09

     View Summary

    In distance education at a simultaneous lecture, this kind of research is without precedent which learners' eyes meet, contactable, their teacher. In this research, the lecture was executed by three different methods. Two of the lectures were executed through Video Conferencing Systems, new one to which a look can be matched and another former one that a look cannot be matched. To them, another was executed by the real facing lecture. In each lecture, questionnaires and learning effect measurement examinations were given. Using them, the comparative analysis of the educational effect were made. From a decentralized analysis of the examination results, result difference was not found among the lectures. Analysis of variance and the multiple comparison estimated the questionnaire evaluation. In addition, factors about understood feeling and study volition were excluded as subjective study evaluation, and then factor analysis were executed. As a result, the following six factors have been extracted: "non-verbal communication" "getting tired" "strain" "a look, real existence desire" "fatigue, dissatisfaction" "relaxation" Each factor was assumed to be an independent variable, examination result, objective study evaluation, and subjective study evaluation were assumed to be a dependent variable. Using them, single recurrence analysis and multiple regression analysis were executed. As a result, the following were clarified. "Non-verbal communication" has a positive influence on the understood feeling, volition, and understanding level. The learning environment which a look cannot be matched becomes an obstacle for the learner's study activity. Although, the distance education with a look can be matched form applies the teaching method for a facing simultaneous lecture, measures against "getting tired" are necessary.


  • 視線一致型TV会議システムを用いた遠隔教育の効果測定

    谷田貝雅典, 坂井滋和

    教育システム情報学会全国大会講演論文集   31st   293 - 294  2006.08


  • A Practical Use of CG-Animation Based Learning Contents for Understanding of the Mechanical Principle of Engine

    SATO Tomoaki, NAGAOKA Keizo, SAKAI Shigekazu, OGUCHI Kosei

    Japan Journal of Educational Technology   29 ( 0 ) 81 - 84  2006.03

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  • The Learning Effect of Web‐contents in Mechanical Engineering Practical Training Subject―The Animation Contents for The Learning of Principle of Diesel Engine―

    佐藤智明, 永岡慶三, 坂井滋和, 小口幸成

    日本機械学会関東支部総会講演会講演論文集   12th   135 - 136  2006.03


  • Effects of videogames on mood states

    Kato Ryo, Ikesita Hanae, Kawai Takashi, Sakai Shigekazu, Sato Takashi, Yamazaki Takashi, Yamagata Hitoshi, Arima Toshio

    The Japanese Journal of Ergonomics   41 ( 0 ) 252 - 253  2005

    DOI CiNii

  • A research on the relationship between visual component parameter of virtual reality space and vection

    TANAKA Nobuhisa, SAKAI Shigkazu

    Proceedings of the Virtual Reality Society of Japan,annual conference   6   251 - 254  2001.09

    CiNii J-GLOBAL

  • CGアニメーションのためのモーションキャプチャーシステムの開発


    九州芸術工科大学研究年報   20   145 - 147  2000


  • An applying of Scientific data for TV programs.


    九州芸術工科大学研究年報   17   113 - 116  1997


  • An Research and Development of Motion Capture System.


    九州芸術工科大学研究年報   15   71 - 73  1995.09


  • Interlock synthesis of CG and photographing in program human body II.


    情報処理学会シンポジウム論文集   94 ( 8 ) 95 - 100  1994.09


  • 1)電子スタジオシステム : 番組「ナノスペース」への適用(映像表現研究会)

    山内 結子, 林 正樹, 福井 一夫, 榎並 和雅, 坂井 滋和

    テレビジョン学会誌   46 ( 7 ) 938 - 939  1992.07


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Overseas Activities

  • 科学・芸術・技術の三角関係 その原点と現状を探る


    マレーシア   UMS

    タイ   シリンドーン国際工学部

    オランダ   アムステルダム応用科学大学

    スウェーデン   ウプサラ大学

Internal Special Research Projects

  • 心奇形実物標本の3次元CG表現とそのデータベース化に関する研究


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