Details of a Researcher - Kohiyama, Masayuki

Kohiyama, Masayuki

写真a

Affiliation: Faculty of Science and Technology, Department of System Design Engineering (Yagami)

Position: Professor

Related Websites

https://kohiyama.sd.keio.ac.jp

External Links

Message from the Faculty Member 【 Display / hide 】

We believe that engineers need to improve their communication skills, problem finding/solving skills, and leadership. By increasing the trust of engineers, excellent products can become more widespread and society can be enriched. the more excellent products will spread and the society will be enriched. In our research activities, we aim to cultivate these skills through uncompromising discussions.

Profile Summary 【 Display / hide 】

This laboratory focuses on performance-based design and optimal design of structures that realize architectural and civil engineering structures with the performance demanded by the users and owners. In order to design the society that has the secure and resilient mechanisms against disasters, the disaster reduction systems and disaster-resistant housing and communities are extensively studied, in which risk evaluation and damage estimation of structures take a leading part.

Career 【 Display / hide 】

1995.04

-

1996.03

Engineer, Architectural and Engineering Design Group, Kajima Corporation
1996.04

-

1999.03

Research Engineer, Kajima Technical Research Institute, Kajima Corporation
1999.04

-

2001.03

Research Scientist, Earthquake Disaster Mitigation Research Center, Riken
2001.04

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2005.03

Research Associate, Institute of Industrial Science, The University of Tokyo
2004.04

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2005.03

Postdoctoral Fellow of Japan Society of Promotion of Science, and Visiting Associate Professor of Stanford University

Academic Background 【 Display / hide 】

1993.03

Kyoto University, Faculty of Engineering, School of Architecture

University, Graduated
1995.03

Kyoto University, Graduate School of Engineering, Department of Architecture and Architectural Engineering

Graduate School, Completed, Master's course

Academic Degrees 【 Display / hide 】

Doctor of Informatics, Kyoto University, Dissertation, 2002.03

Licenses and Qualifications 【 Display / hide 】

first-class registered architect, 1998.02

Research Areas 【 Display / hide 】

Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Structure engineering and earthquake engineering (Structural Engineering, Earthquake Engineering, Maintenance Management Engineering)
Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Building structures and materials (Building Construction/Material)
Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Social systems engineering (Social System Engineering/Safety System)
Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Safety engineering (Social System Engineering/Safety System)
Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Disaster prevention engineering (Natural Disaster Science)

Research Keywords 【 Display / hide 】

Earthquake Engineering
Architectural Structural Engineering

Research Themes 【 Display / hide 】

設備被害を軽減するブロードキャスト対応制震システム,

2016

-

2019

　View Summary

建物内の設備機器と連携して地震時の機能維持を図る，高度な地震対応力を有するアクティブ／セミアクティブ制震システムの実現を目指す。
Cooperative Control of a Building Structure and Multiple Instruments to Enhance Sustainability of their Functions,

2012

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2015

　View Summary

本研究は，建物の制振装置と建物内の機器の制振装置を協調的に動作させる効果的な手法の提案を目的とする。建物内に制振装置を持つ複数の機器が導入されたとき，機能維持のための合理的な制御方法を確立するとともに，制御装置間の通信方法を制御性能・信頼性・保守性・保全性などの観点を踏まえ構築することを目指す。
Autonomous Cooperative Control of a Building-Elevator System Under Long Period Ground Motion,

2010

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2012

　View Summary

In order to reduce elevator rope damage in a high-rise building due to an earthquake, cooperative control of vibration controllers for a building and elevator rope is studied.

Books 【 Display / hide 】

都市・建築レジリエンスデザイン入門

小檜山　雅之，ホルヘ・アルマザン，紙田　和代, 慶應義塾大学出版会, 2020.10
Guidebook of Recommendations for Loads on Buildings

Architectural Institute of Japan, Architectural Institute of Japan, 2016.02

Scope: pp. 1-6

　View Summary

日本建築学会の2015年版「建築物荷重指針・同解説」を活用し性能設計を行うため、設計の流れや設計例、詳細な解説を記載。１章「性能設計の実現に向けて」の1.1節「目標性能水準設定の基本的な考え方と設計者の役割」の執筆を担当。
High-Performance Computing for Structural Mechanics and Earthquake/Tsunami Engineering

Makoto Ohsaki, Tomoshi Miyamura, Masayuki Kohiyama, Takuzo Yamashita, and Hiroshi Akiba, Springer International Publishing, 2015.11

Scope: Seismic Response Simulation of Building Structures (pp. 105-139)

　View Summary

In this chapter, we present an overview of the E-Simulator for application to seismic response analysis of building structures. Accuracy and computational performance of simulation using the E-Simulator are discussed through examples of seismic response analysis of a four-story steel frame, buckling analysis of a column, and simulations of static cyclic responses of a composite beam and an exterior wall. Results of seismic response analysis with fixed base as well as soil-structure interaction analysis are presented for a high-rise building frame. Computational performance using the K computer is also discussed.
Recommendations for Loads on Buildings (2015)

Architectural Institute of Japan, Architectural Institute of Japan, 2015.02

Scope: pp. 95-112

　View Summary

日本建築学会による，建築物の構造設計の際に用いる荷重について，基本理念や考え方を示した指針。１章総則の1.2節基本概念と1.3節用語，２章荷重の種類と組合せの2.1節荷重の種類，2.2節荷重の基本値，2.3節荷重の組合せと要求性能の執筆を担当。
Excelで学ぶ地震リスク評価

小檜山雅之, 技報堂出版, 2011.08

Scope: ４章フラジリティと損傷度の評価, pp. 39-61

　View Summary

日本建築学会荷重運営委員会信頼性工学利用小委員会が，建築工学における確率・統計の利用の普及活動の一環として出版。地震リスク評価について，いくつかの例題をExcel を使って解くことで，ひととおり学べる内容となっている。４章フラジリティと損傷度の評価の執筆を担当。

Papers 【 Display / hide 】

Damage Classification Method for a Wooden Building Based on Hysteresis Loop Using CNN

CHIBA Sohki, KOHIYAMA Masayuki, and YAMASHITA Takuzo

Journal of Japan Association for Earthquake Engineering (Japan Association for Earthquake Engineering) 25 ( 6 ) 74 - 85 2025.05

Research paper (scientific journal), Accepted, ISSN 1884-6246

　View Summary

The shape of the restoring force–story drift angle relationship curve (hysteresis loop) derived from the seismic response data of a building changes depending on the structural health of the building. In this study, we utilized this characteristic for structural health monitoring and proposed a method to assess the risk of collapse due to future earthquake motions based on hysteresis loop images using a convolutional neural network (CNN). We investigated the impact of axis range and resolution settings in the proposed method, comparing the accuracy and recall of the unsafe model in each case. By adjusting the lower limit for the maximum input acceleration of the seismic wave, we achieved a recall of approximately 90% for the unsafe model. Therefore, it can be concluded that the limit of the maximum input acceleration is one of the most influential parameters in damage classification using CNN.
- Access to Document (DOI)
Accuracy Improvement of Damage Classifier for a Wooden Building Considering Pulse-like Seismic Ground Motions

MIZOBUCHI Rikuto, KOHIYAMA Masayuki, and YAMASHITA Takuzo

Journal of Japan Association for Earthquake Engineering (Japan Association for Earthquake Engineering) 25 ( 4 ) 97 - 108 2025.03

Research paper (scientific journal), Accepted, ISSN 1884-6246

　View Summary

Rapid damage assessment by a structural health monitoring system is expected to prevent casualties caused by the collapse of wooden buildings due to repeated seismic motions. While neural networks are known to be a powerful tool for determining the risk of collapse based on the response records, they are not good at classifying untrained damage patterns. This study proposed a method to consider the diversity of damage patterns in the construction of a damage classifier for wooden buildings. This is achieved by using pulse-like simulated ground motions as the input ground motions for seismic response simulation of a target building model in the development of the training dataset. The effectiveness of the proposed method was validated by comparing its accuracy on test data.
- Access to Document (DOI)
Damage Classifier for Wooden Buildings Based on Hysteresis Loop Images Using CNN

Chiba, S., Kohiyama, M., and Yamashita, T.

Proc. of the 18th World Conference on Earthquake Engineering 2024 (WCEE2024) 2024.06

Research paper (international conference proceedings), Joint Work, Accepted

　View Summary

Structural health monitoring (SHM), which evaluates building damage based on seismic response data, is useful for rapidly assessing damage due to earthquakes. If a reliable damage assessment system for houses can be developed, the loss of human lives caused by the aftershocks of major earthquakes can be reduced. When a target building is damaged by strong seismic ground motions, the shape of the restoring force–story drift angle curve (hysteresis loop) changes. Therefore, based on the hysteresis loop images of wooden buildings, this study proposes a method to classify the risk of collapse because of future seismic ground motions using a convolutional neural network (CNN). To develop training data, structural response analysis is conducted using “wallstat”, which is a numerical analysis software for wooden structures. SHM has more severe consequences when it misclassifies an unsafe condition as safe (miss) than when it misclassifies a safe one as unsafe (false alarm). Therefore, we propose the usage of a dataset that does not contain safe model data near the threshold value of major damage for training to decrease the possibility of misses, and we verify the effect of this. In creating the hysteresis loop images, we examine the range of the axes using two methods: fixing it at specific values and matching it to the range of the minimum and maximum values. The investigation results suggest that the trained CNN learns the changes in structural characteristics, such as stiffness reduction, damping increase, and residual displacement.
A Warm Standby Based on the Probability to Exceed Damage Threshold for Seismic Response of a Server

Yusuke KIDA, Enon HIRAOKA, Masayuki KOHIYAMA

Journal of Social Safety Science (Institute of Social Safety Science) ( 43 ) 19 - 27 2023.11

Research paper (scientific journal), Joint Work, Last author, Accepted, ISSN 1345-2088

　View Summary

This study proposes a new warm standby method for computer servers based on seismic response. The proposed method triggers a warm standby in the case that the exceedance probability of the safety limit of seismic response predicted by the last two-second observation record exceeds a preset threshold. Numerical simulations showed that the proposed method reduced the loss cost by 1.64% compared to conventional methods. To validate this method, we conducted shaking table tests. When a simulated earthquake motion was input, the loss cost was reduced by 60.6%. However, when observed records were input, the loss cost was increased by 3.89%. The results suggest that it is necessary improve the input ground motion model.
- Access to Document (DOI)
Development of Tool to Enable Autonomous In-Person and Remote Tabletop Exercises by Residents for Developing Next-Generation Leaders for Volcanic Disaster Reduction

Masayuki KOHIYAMA, Honoka TAKASHIMA, Masayasu YAMAUCHI, Mitsuhiro YOSHIMOTO, Tomohiro KUBO

Journal of Social Safety Science (Institute of Social Safety Science) ( 43 ) 315 - 325 2023.11

Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted, ISSN 1345-2088

　View Summary

To reduce volcanic disasters, it is important for residents to practice mutual support under the leadership of voluntary disaster reduction groups. However, many communities lack the human resource for their future leaders. To address this issue, we proposed a digital tool for residents to develop leaders by themselves. The system requirements were determined to enable residents to conduct autonomous and effective tabletop exercise in both in-person and remote formats. The usefulness of the tool was confirmed through workshops with residents of the areas at the foot of Mt. Fuji.
- Access to Document (DOI)

Papers, etc., Registered in KOARA 【 Display / hide 】

Broadcast responsive vibration control system to reduce damage to facilities

Kohiyama, Masayuki

科学研究費補助金研究成果報告書 2019
Cooperative control of a building and equipment to enhance the functional maintainability

Kohiyama, Masayuki

科学研究費補助金研究成果報告書 2015
Structural assesment and evacuation guidance using small robots

Kohiyama, Masayuki

科学研究費補助金研究成果報告書 2012
Autonomous cooperative control of building-elevator system under long period ground motion

Kohiyama, Masayuki

科学研究費補助金研究成果報告書 2012

Reviews, Commentaries, etc. 【 Display / hide 】

座談会：震災復興から考えるレジリエントな社会

菅原昭彦，福迫昌之，紙田和代，小檜山雅之，厳網林

三田評論 (慶應義塾大学出版会) ( 1253 ) 10 - 26 2021.03

Article, review, commentary, editorial, etc. (bulletin of university, research institution), Joint Work, ISSN 1343-618X
Editorial: Innovative methodologies for resilient buildings and cities

Takewaki I., Kohiyama M., Trombetti T., Tesfamariam S., Lu X.

Frontiers in Built Environment (Frontiers in Built Environment) 5 2019.07
- Access to Document (DOI)
細分化された学問と分断された世界をつなぐ

Masayuki KOHIYAMA

ACe 建設業界 (一般社団法人日本建設業連合会) 80 26 - 26 2017.12

Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work, ISSN 21861862
東日本大震災・熊本地震災害の教訓を生かした建築・まちづくり～建物の「社会性」向上に向けて～

Masayuki KOHIYAMA

月刊不動産流通 (不動産流通研究所) ( 419 ) 8 - 9 2017.04

Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work, ISSN 0286-388X
阪神・淡路大震災20 年シンポジウム「地震被害の軽減に向けた研究者たちのメッセージ―阪神・淡路大震災20 年：地震関連科学の到達点と新たな決意―」開催報告

Masayuki KOHIYAMA

JAEE Newsletter (Japan Association for Earthquake Engineering) 4 ( 1 ) 9 - 12 2015.04

Article, review, commentary, editorial, etc. (scientific journal), Single Work

Presentations 【 Display / hide 】

Development and Response Validation of a Bi-Directionally Tunable Rigid-Body-Swinging and Horizontal-Spring Hybrid Tuned Mass Damper in a Full-Scale Model

Shimizu, Y., Kohiyama, M.

the 14th International Conference on Structural Safety and Reliability (ICOSSAR’25) (University of Southern California, Los Angels, CA) ,

2025.06
,
Oral presentation (general), The International Association for Structural Safety and Reliability

　View Summary

High-rise buildings can be significantly affected by external excitations such as earthquakes and wind and tuned mass dampers (TMDs) are widely used to address this issue. Conventional TMDs can only suppress a single vibration mode. Therefore, a bi-directional tuned mass damper (BTMD) has been proposed for buildings with different natural frequencies in the two horizontal directions. However, adjusting the natural frequency of a BTMD to accommodate changes and uncertainty in the natural frequencies of a building is challenging. This study proposes a novel BTMD named the hybrid tuned mass damper with rigid body swinging and horizontal spring vibration (RH-TMD) as a solution, which combines rolling motion of an auxiliary mass on a rail induced by horizontal spring and swinging motion of the rail and mass in the orthogonal direction. The natural periods can be adjusted by modifying the weight of the mass in rolling motion and the length of the pendulum in swinging motion. A rotary damper with an adjustable damping coefficient is adopted as a damping mechanism.
First, numerical analysis using a 50-story model are conducted to examine the performance of the RH-TMD. The vibration characteristics, natural periods and damping coefficients of the RH-TMD in the two horizontal directions are optimized to minimize the root mean square response to white noise ground acceleration input. Its performance is compared with a conventional (simple) TMD with a natural period and damping coefficient optimized only in a single direction with respect to absolute acceleration and story drift responses to seismic ground motion.
In addition, shaking table experiments are conducted using a small-scale single-layer specimen with a similarity ratio of 1:100, equipped with either an RH-TMD or a simple TMD to compare the responses to white noise ground acceleration and simulated seismic motions.
The results of the numerical analysis and shaking table experiments validate the excellent performance of the RH-TMD in reducing absolute acceleration and story drift responses in the two horizontal directions.
Torsional Response Due to Q–Δ Effect and Its Internal Resonance

Kohiyama, M.

the 14th International Conference on Structural Safety and Reliability (ICOSSAR’25) (University of Southern California, Los Angels, CA) ,

2025.06
,
Oral presentation (invited, special), The International Association for Structural Safety and Reliability

　View Summary

The P–Δ effect is well known, in which an overturning moment emerges due to geometric nonlinearity when a gravity-loaded structure undergoes a large deformation. Similarly, when a column undergoes a large horizontal displacement, a torsional torque emerges to preserve the state of equilibrium. The speaker named this effect “Q–Δ effect.” Although the effect has not been considered in structural design, he has shown that periodical nonlinear restoring torque of the Q–Δ effect can produce a non-negligible torsional response in a structure during earthquakes owing to its internal resonance, named “Q–Δ resonance.” This talk will first explain the theory of the Q–Δ effect and the mechanism of the Q–Δ resonance. Then, he will present the results of shaking-table experiments using a reduced specimen and finite element analysis of a full-scale model of high-rise building under long period ground motions. This resonance phenomenon is a blind spot in seismic design, and given the mechanism of its occurrence, it may need to be considered in wind-resistant design as well. Researchers and engineers are expected to listen to this talk to widely promote proactive countermeasures.
Accuracy Improvement of Damage Classifier for a Wooden Building Using Long Short-Term Memory with Response Surface Method

Shimizu, Y., Kohiyama, M. Yamashita, T.

the 14th International Conference on Structural Safety and Reliability (ICOSSAR’25) (University of Southern California, Los Angels, CA) ,

2025.06
,
Oral presentation (general), The International Association for Structural Safety and Reliability

　View Summary

Structural health monitoring (SHM) has attracted significant attention as a method for rapidly and efficiently assessing the damage state of buildings immediately after an earthquake. Application of SHM to houses could facilitate prompt evaluations of the risk of collapse from subsequent earthquakes, thereby reducing casualties caused by aftershocks and other seismic events. This study proposes a damage classification method for wooden buildings based on acceleration responses, using long short-term memory (LSTM), which is well-suited for capturing the long-term dependencies of time-series data.
The analysis focuses on a specimen from the dataset of “Experimental Validation of Design Methods for Three-Story Wooden Frame Structures,” published by the National Research Institute for Earth Science and Disaster Resilience. A building model was constructed and analyzed using “wallstat,” a numerical analysis software for wooden structures. To generate training data for a damage classifier, response analysis of the model was conducted using 2,000 simulated seismic ground motions consisting of equal number of pulse and non-pulse types ground motions. The acceleration response of the first and second floors were converted input data for the damage classifier so that each input segment contains one second of acceleration responses. To prevent data imbalance caused by similar input segments with small variations in acceleration, a “lag” was introduced, ensuring that each input segment shifts by a specific number of data points relative to the previous one.
In SHM, misclassifying an unsafe condition as safe poses a severe risk to building users, as users may overlook potential building collapse hazards leading to fatalities. To address this, training data near the threshold between safe and unsafe models were excluded from safe model datasets to reduce the possibility of misclassification.
Three hyperparameters of the damage classifier, the number of LSTM units, the number of nodes in the first fully connected layer, and the learning rate, were optimized using the response surface method. This optimization process identified a combination of hyperparameter values that achieved high classification accuracy. A two-level central composite design was employed for the design of experiments.
The proposed damage classifier demonstrated a high accuracy of 92.4%, marking a significant step toward practical implementation. This study highlights the effectiveness of LSTM for damage classification in wooden buildings and underscores the utility of the response surface method in optimizing machine learning models.
3次元畳み込みニューラルネットワークを用いた履歴ループに基づく木造建物の損傷判別システム

千葉荘輝，小檜山雅之，山下拓三

日本地震工学会・大会－2024 (じゅうろくプラザ（岐阜市文化産業交流センター，岐阜市）) ,

2024.12
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Oral presentation (general), Japan Association for Earthquake Engineering

　View Summary

The shape of the restoring force–story drift angle relationship curve (hysteresis loop) derived from the seismic response data of a building changes depending on its structural health. Taking advantage of this property, this study proposed a method to assess the risk of collapse due to future earthquake motions based on hysteresis loop images considering the time axis direction using a three-dimensional convolutional neural network (CNN). The effectiveness of the proposed method was verified by comparing the accuracy and recall of the unsafe model between the proposed method and a prior research method using a two-dimensional CNN. It was confirmed that the proposed method adjusting the image size and division number in the time axis direction has a higher accuracy and robustness against observation noise.
Shaking Table Experiment of a Rigid Body Swing and Horizontal Spring Oscillation Combined Type Tuned Mass Damper Tunable in Two Directions

SHIMIZU Yuki, KOHIYAMA Masayuki

Annual Meeting of Architectural Institute of Japan (Surugadai Campus, Meiji University (Chiyoda-ku, Tokyo)) ,

2024.08
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Oral presentation (general), Architectural Institute of Japan

Research Projects of Competitive Funds, etc. 【 Display / hide 】

Resilient Vibration Control Method Considering Functional Continuity and Rapid Restoration

2020.04

-

2024.03

MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator
Broadcast Responsive Vibration Control System to Reduce Damage to Facilities

2016.04

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2020.03

MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator

Intellectual Property Rights, etc. 【 Display / hide 】

振動制御システム

Date applied： 2011-157501 2011.07

Date announced：特開2013-23844

Date issued： 5828699 2015.10

Patent, Joint
建物データポリゴン化システム、その方法および建物データポリゴン化プログラム

Date applied：特願2001-23850 2001.01

Date announced：特開2002-230589 2002.08

Date issued： 3394525 2003.01

Patent
フランジ付中間鋼板を使用した積層ゴム支承

Date applied：特許出願平9-66319 1997.03

Date announced：特許公開平10-266624 1998.10

Patent

Courses Taught 【 Display / hide 】

SPECIAL LECTURE ON SPACE AND ENVIRONMENT DESIGN ENGINEERING 1

2025
SOCIETY, ECONOMY, CULTURE, AND ENGINEERING

2025
SEMINAR IN SYSTEM DESIGN ENGINEERING

2025
PROBABILITY AND STATISTICS

2025
MATHEMATICAL PROGRAMMING FOR DESIGN AND PLANNING

2025

Courses Previously Taught 【 Display / hide 】

Probability and Statistics

Keio University

2014.04

-

2015.03
,
Spring Semester, Lecture
社会・経済・文化と工学

Keio University

2014.04

-

2015.03
,
Autumn Semester
設計・計画の最適化数理

Keio University

2014.04

-

2015.03
,
Autumn Semester, Lecture
空間設計製図Ｉ

Keio University

2014.04

-

2015.03
,
Autumn Semester, Seminar
理工学基礎実験

Keio University

2014.04

-

2015.03
,
Autumn Semester, Laboratory work/practical work/exercise

Social Activities 【 Display / hide 】

Research Fellow

Institute of Industrial Science, the University of Tokyo
,
2024.04

-

2027.03

　View Summary

既存不適格建物の耐震改修促進に関する研究
国立研究開発法人防災科学技術研究所数値震動台研究開発分科会データサイエンスWG 主査

National Research Institute for Earth Science and Disaster Resilience
,
2020.08

-

2023.03
国立研究開発法人防災科学技術研究所数値震動台研究開発分科会委員

National Research Institute for Earth Science and Disaster Resilience
,
2019.09

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2023.03
Lecturer of Group Training Course of Seismology and Earthquake Engineering

International Institute of Seismology and Earthquake Engineering, Building Research Institute, (Building Research Institute (Tsukuba, Ibaraki))
,
2017.02

-

Present

　View Summary

Subject: Structural Response Control
国立研究開発法人防災科学技術研究所数値震動台研究開発分科会建築WG委員

National Research Institute for Earth Science and Disaster Resilience
,
2016.05

-

2023.03

Memberships in Academic Societies 【 Display / hide 】

Japan Society of Civil Engineers

　
Earthquake Engineering Research Institute

　
Institute of Social Safety Science

　
Japan Association for Earthquake Engineering

　
Architectural Institute of Japan

Committee Experiences 【 Display / hide 】

2025.05

-

2027.05

Auditor of the Board of Directors , Japan Association for Earthquake Engineering
2025.04

-

2029.03

Member of Managing Committee on Loads and Actions on Buildings, Architectural Institute of Japan
2025.04

-

2029.03

Chair of Subcommittee on Structural Control, Architectural Institute of Japan
2025.04

-

2027.03

Chair of Managing Committee on Loads and Actions on Buildings, Architectural Institute of Japan
2023.04

-

2025.03

地震保険研究事業評価委員会委員長, 損害保険料率算出機構