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Engineering educational research section Department of Civil and Environmental Engineerring Program |
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MORITA Chihiro
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Degree 【 display / non-display 】
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博士（工学） ( 1996.7 九州大学 )
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工学修士 ( 1990.3 長崎大学 )
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工学士 ( 1988.3 長崎大学 )
Research Areas 【 display / non-display 】
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Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Structure engineering and earthquake engineering
Papers 【 display / non-display 】
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CNN AND GAN BASED WEATHERING STEEL APPEARANCE EVALUATION IMPROVED BY IMAGE SIZE AND LOSS FUNCTION Reviewed
Nagatani K., Shigei N., Morita C., Ishizuka Y., Miyajima H.
International Journal of Innovative Computing, Information and Control 21 ( 2 ) 433 - 445 2025.4
Publishing type：Research paper (scientific journal) Publisher：International Journal of Innovative Computing, Information and Control
Weathering steel is a steel material that can maintain its performance outdoors for a long period of time by forming protective rust. Periodic inspection of the rust condition is necessary to maintain this steel in good condition, and CNN-based methods for evaluating the appearance of rust have been studied. One of the problems in improving the classification accuracy of the CNN is how to prepare the rust images for training. The objectives of this paper are 1) to consider rust patch image size and 2) to improve the diversity of the generated images in rust image generation using GAN. From 1), we show that the accuracy can be improved by using large cropping images and shrinking the image when training the model. From 2), we propose SSIM-target loss, which is an improvement of the conventional SSIM loss, and show that it improves the CNN Score. Using methods 1) and 2), we achieved an F1 score of 90.3% for the three-class classification of the rust images, compared to the baseline method’s F1 score of 86.8%.
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Numerical study on the melting behavior of annular fuel under accident conditions Reviewed International coauthorship
Wang B., Huang M., Meng X., Ouyang X., Huang Y., Matsuda H., Morita C.
Progress in Nuclear Energy 179 2025.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Progress in Nuclear Energy
The use of annular fuel in nuclear power plants has been developed to improve their efficiency, safety, and economic viability. Therefore, studying the thermal hydraulic issues of annular fuel is crucial. The melting of annular fuel under accident conditions is equally important. This study uses a novel numerical technique called the Half Boundary Method (HBM) to tackle this issue. With new variables introduced, this method avoids the need for additional continuity equations at the boundary when solving multi-layer composite problems. First, the HBM is used to model a multi-layer composite ring and solve its transient thermal problems, which are then verified. Next, the temperature distribution of annular fuel under operational conditions is calculated, and the results are compared to validate HBM's accuracy. Based on these findings, simulations are conducted to model the melting phase transitions of annular fuel during Loss of Coolant Accidents (LOCAs) and Reactivity Insertion Accidents (RIAs).
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Improvement of GAN-based Training Image Generation for CNN-based rust Evaluation of Weathering Steel Reviewed
Nagatani K., Shigei N., Morita C., Ishizuka Y., Miyajima H.
ACM International Conference Proceeding Series 40 - 47 2024.12
Publishing type：Research paper (scientific journal) Publisher：ACM International Conference Proceeding Series
Weathering steel is a steel material that produces a protective rust layer on the surface of the steel that suppresses the propagation of corrosion. Periodic inspection of the rust condition is necessary to maintain this steel in good condition, and CNN-based methods for evaluating the appearance of rust have been studied. One of the problems in improving the classification accuracy of the CNN is how to prepare the rust images for training. Since it is difficult to collect rust images in the real world, it has been studied to train CNN with rust images generated by GANs. Conventional GANs have the problem that when a large number of images are generated, the generated images are biased toward similar ones. The scope of this paper is to improve the accuracy of CNN using GAN-generated images in classification tasks of rust conditions of weathering steel. The specific objectives of this study are to improve the diversity of images generated by GANs and thereby improve the accuracy of CNNs. To improve image diversity in GAN-based image generation, we propose to use Wasserstein GAN with Gradient Penalty (WGAN-GP), in addition to Conditional GAN (CGAN), and to introduce SSIM (Structural Similarity) and LBP (Local Binary Pattern) as loss functions, in addition to L1 and L2 losses. Then, the images generated by the proposed five types of GANs are applied to the training of CNNs. Comparison between the proposed GANs and the conventional CGAN shows that 1) the proposed GANs can reduce the SSIM similarity of the generated images by up to 1/4, and 2) in the classification of three classes of rust images, the use of the generated images of the proposed GANs can improve the F1 score by up to about 4%pt. Overall analysis shows that WGAN-GP-based is better than CGAN-based and that the newly introduced SSIM, LBP, L1 and L2 losses improve both similarity and classification accuracy.
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A boundary-type algorithm based on the discrete ordinates for neutron transport equation Reviewed International coauthorship
Cheng Y.T., Huang M., Ouyang X.P., Matsuda H., Morita C.
Engineering Analysis with Boundary Elements 169 2024.12
Publishing type：Research paper (scientific journal) Publisher：Engineering Analysis with Boundary Elements
The spatial distribution of neutron flux in the core of a nuclear reactor plays a crucial role in ensuring nuclear safety. It can be determined by solving the neutron transport equation, where computational resource consumption is gradually receiving more attention, especially in problems with multiple reflective boundary conditions. It is common practice to assume initial boundary values in one angular direction to obtain a global solution, and then use reflective boundary conditions to solve for the other directions, iterating until convergence. However, this approach has the drawback of requiring the global solution, and each iteration necessitates storing the neutron flux values, consuming time and storage space. In order to address this issue, this paper proposes a precise and efficient boundary-type method, the Half Boundary Method (HBM). This method establishes relationships between adjacent node values through integration and mathematical deduction, ultimately obtaining the relationship among any node and the boundary values in any direction. As a result, iteration is only required for boundary values, reducing the iteration amount and thus saving time and storage space. Using the discrete ordinate (SN) method for angular discretization and HBM for spatial discretization, this paper solved the steady-state neutron transport equation for two-dimensional systems modeled with Cartesian geometry. The method is validated using several benchmark problems, including the 2D ISSA benchmark, the 2D mono-group k-eigenvalue problem and BWR rod bundle test problem. All of these problems demonstrate good results and effectively reduced computational time.
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Nakano A., Toyota Y., Morita C., Yasui K., Oshikawa W., Yonezawa N.
International Journal of Steel Structures 2024.9
Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Steel Structures
This paper presents the results of a study comparing the initial corrosion characteristics of thermal spray coatings on Zn, Zn-Al, and Al–Mg thermal spray coatings after one year atmospheric exposure tests at two atmospheric environment sites. The thermal spray coatings were obtained by electroric arc spraying of various metals onto a carbon steel substrate. Atmospheric exposure tests were also conducted for outdoor accelerated exposure tests in which test specimens were applied with artificial seawater. The corrosion properties of these spray coatings were evaluated by surface analysis, film thickness measurements, cross-sectional analysis and anodic/cathodic polarization measurement. After one year of atmospheric exposure testing, white, granular corrosion products were observed on the surface of the Zn and Zn-Al thermal spray coatings, while no significant changes were observed in the Al–Mg thermal spray coating. Similar results were obtained for the surfaces of test specimens in atmospheric exposure tests with artificial seawater. The thickness of the thermal spray coating increased for the Zn thermal spray coating, while no significant change was observed for the other thermal spray coatings. Thus, differences in corrosion behavior were observed due to the composition of the thermal spray coatings. The initial corrosion behavior of the thermal spray coatings was also investigated based on the results of coating morphology and cross-sectional elemental distribution of the coatings.
Books 【 display / non-display 】
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これだけは知っておきたい橋梁メンテナンスのための構造工学入門
委員長：岩城一郎 他（ Role： Joint author）
建設図書 2019.5
Language：Japanese Book type：Textbook, survey, introduction
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耐候性鋼橋梁の可能性と新しい技術
主査：山口栄輝 他（ Role： Joint author）
日本鋼構造協会 テクニカルレポート 2006.10
Language：Japanese Book type：Scholarly book
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ロマンを訪ねて～九州橋紀行
九州橋梁・構造工学研究会 主査：﨑元達郎 他（ Role： Joint author）
西日本新聞社 1995.7
Language：Japanese Book type：General book, introductory book for general audience
MISC 【 display / non-display 】
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進化するRC構造物の非破壊検査2003 非破壊検査の手法【目で見る】3D Invited
森田千尋，出水享
建築技術 ( 881 ) 101 - 102 2023.6
Authorship：Lead author, Corresponding author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal)
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進化するRC構造物の非破壊検査2003 非破壊検査の手法【表面で計測する】光学的ひずみ計測 Invited
森田千尋，出水享
建築技術 ( 881 ) 122 - 123 2023.6
Authorship：Lead author, Corresponding author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal)
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デジタル画像相関法を用いた橋梁の亀裂・変位・ひずみ計測に関する研究 Invited
出水享，松田浩，伊藤幸広，森田千尋
光技術コンタクト 60 ( 2 ) 32 - 39 2022.2
Authorship：Last author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal)
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「橋の日」の制定・活動と47都道府県橋の日運動の支援 Invited
森田千尋
土木学会誌 ( 8月 ) 60 - 61 2021.8
Authorship：Lead author Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal)
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宮崎大学工学部で行った高校生「総合的な探究の時間」の評価
田村宏樹、森田千尋、盆子原康博、荒井昌和、菅本和寛、坂本眞人、石津貴弘
宮崎大学工学部紀要 49 17 - 22 2020.9
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution)
Presentations 【 display / non-display 】
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深層学習を用いたコンクリート構造物のひび割れ幅推定
永田琥太郎，中丸ゆかり，安井賢太郎，森田千尋，川畑琉皇，重井徳貴
令和6年度土木学会西部支部研究発表会
Event date： 2025.3.8
Language：Japanese Presentation type：Oral presentation (general)
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3年間の大気暴露試験における機能性防錆塗装システムの防食特性の比較
宮崎琉太郎，森田千尋，中野敦，堀澤英太郎，博多屋智志，森本菖
令和6年度土木学会西部支部研究発表会
Event date： 2025.3.8
Language：Japanese Presentation type：Oral presentation (general)
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SfMモデルを用いた解体橋梁桁のひび割れ幅計測の検討
池内亮磨，森田千尋，堀澤英太郎，安井賢太郎，出水享
令和6年度土木学会西部支部研究発表会
Event date： 2025.3.8
Language：Japanese Presentation type：Oral presentation (general)
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九州・山口地区の耐候性鋼橋梁における約20年間のさび外観変化
清瀬啓文，森田千尋，堀澤英太郎，熊本仁美，中島和俊，安井賢太郎
令和6年度土木学会西部支部研究発表会
Event date： 2025.3.8
Language：Japanese Presentation type：Oral presentation (general)
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三次元計測技術による鋼部材を対象とした寸法精度の検証
細石波留斗，森田千尋，堀澤英太郎，安井賢太郎，池内亮磨
令和6年度土木学会西部支部研究発表会
Event date： 2025.3.8
Language：Japanese Presentation type：Oral presentation (general)
Awards 【 display / non-display 】
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令和6年度土木学会西部支部研究発表会優秀講演賞
2025.3 公益社団法人土木学会西部支部
永田琥太郎，中丸ゆかり，安井賢太郎，森田千尋，川畑琉皇，重井徳貴
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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令和6年度土木学会西部支部研究発表会優秀講演賞
2025.3 公益社団法人土木学会西部支部
森本菖，森田千尋，中野敦，堀澤英太郎，押川渡，米沢昇
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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令和6年度土木学会西部支部研究発表会優秀講演賞
2025.3 公益社団法人土木学会西部支部
宮崎琉太郎，森田千尋，中野敦，堀澤英太郎，博多屋智志，森本菖
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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令和6年度土木学会全国大会第79回年次学術講演会優秀発表賞
2024.10 公益社団法人土木学会
森本菖，森田千尋，中野敦，堀澤英太郎，押川渡，米沢昇
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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令和5年度土木学会西部支部研究発表会優秀講演賞
2024.3 公益社団法人土木学会西部支部
森本菖，森田千尋，中野敦，押川渡，豊田祐樹，米沢昇
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
Grant-in-Aid for Scientific Research 【 display / non-display 】
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耐候性鋼のさび外観評点区分の検討と三次元データを用いた橋梁の健全度評価手法の構築
Grant number：24K07642 2024.04 - 2027.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(C)
Authorship：Principal investigator
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3次元データを用いたインフラ構造物の点検・診断システムの高度化・高精度化
Grant number：22K04268 2022.04 - 2025.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(C)
Authorship：Coinvestigator(s)
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地方橋梁の三次元モデルの構築と効率的・効果的な復元設計による維持管理環境の創出
Grant number：20K04666 2020.04 - 2023.03
独立行政法人日本学術振興会 科学研究費補助金 基盤研究(C)
Authorship：Principal investigator
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橋梁狭隘箇所の変状認識を目的とするGNSSを採用したUAV自律航行システムの開発
Grant number：18K04305 2020.04 - 2021.03
科学研究費補助金 基盤研究(C)
Authorship：Coinvestigator(s)
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３次元データを用いたインフラ構造物の革新的点検・診断システムの開発
Grant number：19K04556 2019.04 - 2021.03
科学研究費補助金 基盤研究(C)
Authorship：Coinvestigator(s)
Available Technology 【 display / non-display 】
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多視点画像解析を用いた構造物の3次元モデル化と橋梁点検への活用
防食技術（溶射、機能性防錆塗装システム）の腐食性評価に関する研究
耐候性鋼橋梁の健全度評価手法に関する研究Home Page： 土木環境工学プログラム
Related fields where technical consultation is available：・橋梁（特に鋼橋梁）の点検、診断、補修・補強に関する内容
・構造物の構造解析、実験Message：構造物（特に鋼橋梁）の維持管理に関する研究を行っています。これらに関するご相談に対応できると思います。
また、学び直し講座として、橋梁点検技術者養成講座を実施しています。