Elsevier BV Acta Medica Okayama 0266-352X 178 2025 End-to-end time-dependent probabilistic assessment of landslide hazards using hybrid deep learning simulator 106920 EN Menglu Huang Department of Civil and Environmental Engineering, Okayama University Shin-ichi Nishimura Department of Civil and Environmental Engineering, Okayama University Toshifumi Shibata Department of Civil and Environmental Engineering, Okayama University Ze Zhou Wang Marie Skłodowska-Curie Fellow, Department of Engineering, University of Cambridge Early warning detection of landslide hazards often requires real-time or near real-time predictions, which can be challenging due to the presence of multiple geo-uncertainties and time-variant external environmental loadings. The propagation of these uncertainties at the system level for understanding the spatiotemporal behavior of slopes often requires time-consuming numerical calculations, significantly hindering the establishment of an early warning system. This paper presents a hybrid deep learning simulator, which fuses parallel convolutional neural networks (CNNs) and long short-term memory (LSTM) networks through attention mechanisms, termed PCLA-Net, to facilitate time-dependent probabilistic assessment of landslide hazards. PCLA-Net features two novelties. First, it is capable of simultaneously handling both temporal and spatial information. CNNs specialize in interpreting spatial data, while LSTM excels in handling time-variant data. Coupled with two attention mechanisms, the two modules are combined to probabilistically predict the spatiotemporal behavior of slopes. Second, PCLA-Net realizes end-to-end predictions. In this paper, the Liangshuijing landslide in the Three Gorges Reservoir area of China is used to illustrate PCLA-Net. It is first validated followed by a comparison with existing techniques to demonstrate its improved predictive capabilities. The proposed PCLA-Net simulator can achieve the same level of accuracy with at least 50% reduction in computation resources. No potential conflict of interest relevant to this article was reported.

Elsevier Acta Medica Okayama 00380806 61 2 2021 Reliability-based design for earth-fill dams against severe natural disaster events 271 282 EN Shin-ichi Nishimura Graduate School of Environmental and Life Science, Okayama University Toshifumi Shibata Graduate School of Environmental and Life Science, Okayama University Takayuki Shuku Graduate School of Environmental and Life Science, Okayama University The maintenance of geotechnical structures, such as earth-fill dams, is required as a countermeasure against severe natural disasters, particularly earthquakes and heavy rains. The reliability-based analysis introduced here is in response to the recent demand for low-cost improvements.First, a statistical model of N values was determined from Swedish weight sounding (SWS) tests to present the spatial variability of the soil strength. Then, a reliability-based analysis of embankments was conducted by considering the variability of the internal friction angle derived from N value, and the seismic hazard for the Nankai Trough. The next step was to evaluate the probability of the overflow of earth-fills during heavy rains. The rainfall intensity was considered as a probabilistic parameter, and the various rainfall patterns were tested by the proposed method. Finally, the total risk due to both earthquakes and heavy rains was evaluated for an earth-fill site. As a result, the possibility for the practical use of the proposed method in making plans for the maintenance of deteriorated earth-fill dams was verified. No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 13419099 25 1 2020 3次元計測を利用した効率的な3次元有限要素モデル化法の提案 1 4 EN Minoru KANESHIGE Shin-ichi NISHIMURA Toshifumi SHIBATA Takayuki SHUKU 10.18926/fest/58060 In this decade, 3-dimensional topographic survey has been developed by using the UAV as like drones. With the technique, the complete topographies of the geo-structures can be measured. Although the accurate shapes of the geo-structures can be obtained, the numerical methods as like the finite element method is are not related to the 3-dimensional survey directly. In this research, the finite mesh modelling technique with use of the 3-D topographic survey is developed. The models of the earth-fill embankments formed from measured 3-D data are introduced as the examples. No potential conflict of interest relevant to this article was reported.

岡山大学環境管理センター Acta Medica Okayama 0917-1533 38 2016 地球環境問題と環境マネジメント 1 1 EN Shin-ichi Nishimura No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 2014 Simplified approach to evaluate total external loading to Kojima Lake 76 92 EN Shin-ichi NISHIMURA Kenji OKUBO Hidenori MORITA Jari KOSKIAHO Sirrka TATTARI No potential conflict of interest relevant to this article was reported.

岡山大学保健環境センター環境安全部門 Acta Medica Okayama 0917-1533 26 2004 編集後記 62 EN Shin-ichi Nishimura No potential conflict of interest relevant to this article was reported.

岡山大学保健環境センター環境安全部門 Acta Medica Okayama 0917-1533 27 2005 編集後記 55 EN Shin-ichi Nishimura No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 1 1 1996 Settlement Prediction Method Using Observed Settlement Velocity 193 198 EN Kiyoshi Shimada Sin-ichi Nishimura Hiroaki Fujii 10.18926/fest/11639 This paper presents a new method for prediction of consolidation settlements of soft grounds. The method is based on the theoretical result which shows that the settlement velocity of soft grounds non-improved or improved with sand drains decreases exponentially with time. Final settlements can be easily derived from the regression analysis for the relationship between the elapsed time and the observed settlement velocity. The method has advantages of its simplicity and capability to give the satisfactorily good estimate of the consolidation settlements, and also the support of the theoretical background. No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 1 1 1996 Prediction of Pore Water Pressures in Several Embankment Dams by Normal and Back Analyses 181 192 EN Hiroaki Fujii Mutsuya Narita Kiyoshi Shimada Shinichi Nishimura 10.18926/fest/11636 This paper describes the prediction of seepage in the impervious zones of six embankment dams by seepage analysis. In addition, by making use of the available monitored pore water pressure data of the first filling of reservoir, back analysis was carried out to estimate the best fit seepage parameters. The estimated parameters were used for further prediction of pore water pressures in subsequent monitored durations with reasonable accuracy. The accuracy of prediction was evaluated quantitatively by the prediction difference and error index. The results show that the error indices in the upstream sides of the impervious zones are smaller than those in the downstream sides. No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 2 1 1997 Determination of Crossarm Installation in Fill Dams by Back Analysis 107 120 EN Hiroaki Fujii Kiyoshi Shimada Shin-ichi Nishimura 10.18926/fest/11612 This paper discusses a numerical model that can be used to optimize the installation in a zoned type and a homogeneous type fill dam. Before installation in a real dam to evaluate dam behavior, numerical model described in this paper is carried out on a prototype dam to check the optimum installation, using cross arm measurements. Three cross arm installations at the upstream, the core and downstream to measure displacements are considered. The installation options considered are three cross arm combinations for best installation to verify the safety of dams and to reduce cost. Finite element method is used for generating the displecement field in a linear elastic numerical model. The generated data is used as an input data in the back analysis to check the adequacy of each installation option. No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 5 1 2000 現場試験による液状化強度の評価と信頼性設計への適用 145 151 EN Shin-ichi Nishimura Hideyoshi Shimizu Hiroaki Fujii Kiyoshi Shimada 10.18926/fest/11591 A calculation method of probability of liquefaction is proposed in this paper. The spatial variability of soil parameters for the dynamic shear strength, i.e., N-values, median grain size, fines contents, and the statistical characteristics of the earthquake frequency are considered in the analysis. The standard penetration test (SPT) is convenient to estimate the spatial variability of the dynamic shear strength and mainly used in this study. Furthermore the determination of dynamic shear strength based on Swedish weight Sounding test also introduced here, because it is the simpler test than SPT. While the statistical model of the earthquake frequency is determined based on the record of historical earthquakes. Using this method the probability of liquefaction is calculated. The sand compaction pile method is considered for the ground improvement against the liquefaction. Finally, the relationship between the sand replacement rate and the probability of liquefaction is clarified. No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 6 1 2001 浚渫ヘドロ脱水ケーキの一次元圧縮試験 85 97 EN Yoshiaki Wakitani Hiroaki Fujii Shin-ichi Nishimura Takashi Inoue 10.18926/fest/11539 One-dimensional compression tests were performed to investigate compression characteristics of sludge cake used as a construction material. The sludge cake is dewatering product of dredged sludge from the bottom of a lake. The test results show following compression characteristics. (1) For the undisturbed samples, e-log p curves show compressibility of overconsolidated clay ordinatily observed. (2) For the disturbed samples, there observed compressibility close to that of ordinary normally consolidated clay. (3) For the recompressed samples, there observed two turning points on e-log p curve. The compression presures(p(c1) and p(c2)) at those points for the unsubmerged tests have a linear correlation with the recompression pressure(p(s)). The submerged tests give very small values of p(c1) and p(c2) compared with the case of unsubmerged test. (4) For the recompressed samples, the first compression index(C(c1)) after p(c) has a linear correlation with the initial void ratio(e(0)), and the second compression index(C(c2)) shows almost constant value. No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 7 1 2002 兵庫県南部地震による北淡町を中心にしたため池の被害の要因分析 55 74 EN Hiroaki Fujii Kana Kunimasa Akiyo Nanba Takayuki Yokomizo Shin-ichi Nishimura Kiyoshi Shimada Toshio Hori Tatsuro Nishiyama Yoshiaki Wakitani 10.18926/fest/11528 This study was performed to clarify which factors affected damage to take-ike (small embankment dams for irrigation in Japanese) of Hokudan Town on Awaji Island in western Japan due to Hyogoken-Nambu earthquake. Multivariate and ordinary statistical analysis were carried out using documentary data (181 damaged and 328 undamaged dams), and ordinary one was done for the results investigated in situ. The model for the multivariate analysis was created with 13 items and 94 categories for 4 groups (Location, Geology Structure, and History of Dam). As a result, the factors causing to damage for dam are (1) the nearest fault (Nojima, Mizukoshi and D2), (2) embankment volume (the larger the more), (3) angle of crest axis to epicenter (diagonal and normal), (4) distance to the nearest fault (less than 500 m), (5) distance to the epicenter (8 to 14 km which almost agree to the location of seismic intensity 7 JMA), (6) play view of dam axis (3 or 4 axes), (7) angle of crest axis to nearest fault (diagonal and normal), (8) elevation of dam site (over 100 m), (9) surface geology of dam site (non-cohesive soil), (10) era of construction (prior to 1891), and (11) soil properties of embankment (constructed of sand, smaller penetration resistance). No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 11 1 2006 乾燥による底泥の性質変化 83 88 EN Tomoaki Takisawa Shin-ichi Nishimura Akira Murakami 10.18926/fest/11438 To examine the possible reuse of dredged sludge in view of construction material, physico-chemical properties and geotechnical characteristics of desiccated sludge are investigated through laboratory experiments. The consistency test, the pH test, the XRF test and the X-ray diffraction analysis are carried out for physico-chemical proteries, and the conolidation test and the permeability test are made for geotechnical characteristics. It is concluded that the history of desiccation changes the consistency of sludge and affects its permeability and consolidation bahavior. No potential conflict of interest relevant to this article was reported.

岡山大学農学部 Acta Medica Okayama 0474-0254 83 1 1994 確率有限要素法の精度に関する2,3の考察 43 51 EN Shin-ichi Nishimura Hiroaki Fujii (1)確率有限要素法の二手法である線形近似法とモンテカルロ法についての定式化を示した.特に,モンテカルロシミュレーションについては,一変数一次元確率場と一変数二次元確率場の乱数発生法について示した. (2)ヤング率の自己相関関数を表現するのに必要な要素分割数について考察を行った.その結果,本解析モデルに関しては,10～15分割で変位の平均値,標準偏差が収束することが分かった (3)線形近似法とモンテカルロ法の結果の比較を行った.それによると,線形近似法の結果は,ヤング率の変動係数が0.2の場合まではモンテカルロ法の結果とよく一致するという結論が得られた.ただし,変位の平均値における二手法間での相違は,ヤング率の変動係数が大きい場合でも,本研究の例題に関しては実務上無視しても差し支えないほどの大きさであることが分かった. 本研究の数値計算には,岡山大学情報処理センターのACOS2010,SX-1Eを使用した。 No potential conflict of interest relevant to this article was reported.