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出水時の河道特性が破堤拡幅現象に与える影響に関する研究
Get PDF北見工業大学博士（工学）近年，台風や局所的な集中豪雨などに起因した出水により大規模水害の発生リスクが高まってきており，河川堤防の整備が進んでいる今日でも全国各地で破堤が生じている．特に越水による破堤は河道水位の高い状態から一気に堤内地側に氾濫流が流れ込むことで，広範囲・長時間にわたり冠水するなど，流域の生活・産業に大きな影響が生じる．よって破堤による被害を少しでも抑えることは河川防災にとって喫緊の課題の一つである．
このような中，破堤被害軽減技術の構築には破堤拡幅メカニズムの解明が不可欠であるが，出水時の河道特性に応じた破堤拡幅進行過程は明らかになっていない．本研究は，出水時の河道特性が破堤拡幅現象に与える影響を解明するとともに，破堤被害軽減に向けた効果的で効率的な緊急対策工法の考え方を提案することを目的とする．本研究により以下の研究成果が得られた．
1） 様々な破堤事例を収集整理し，越水破堤水理模型実験や数値解析を行った結果，破堤拡幅現象に影響を与える要素は川幅と越水時の水面勾配にほぼ等しいと考えられる計画高水勾配であることが明らかとなった．勾配が急な河川では川幅の広狭によらず氾濫流況は河道から氾濫域に向かい斜め下流方向へ流出し，破堤開口部は下流縦断方向への拡幅進行が卓越すること，勾配が緩やかな河川では川幅が広くなるほど氾濫流況は堤防に対して直角方向へ流出し，破堤開口部は拡幅進行よりも落掘発達が卓越することなどが明らかとなった．さらに計画高水勾配に応じた破堤時の氾濫流向を推定しておくことで，これらの関係より破堤拡幅現象を事前に想定出来ることを示した．
2） 支川背水区間における破堤拡幅現象に影響を与える要素は川幅のほか，支川の自流量の相違であることが明らかとなった．川幅が狭く自流量が少ないほど本川からの逆流が卓越し，氾濫流況は河道から氾濫域に向かい斜め上流方向へ流出し，破堤開口部は上流縦断方向へ拡幅進行すること，川幅が広く自流量が大きいほど氾濫流況は堤防に対して直角方向に流出し，正面越流に近い破堤拡幅現象を示すことなどが明らかとなった．これは同一の河道形状・地点であっても，背水区間では本川と支川の流況の関係により破堤拡幅現象・被害形態が異なるため，緊急対策工法も現象に応じた対応方法を考える必要があることを示した．
3） 荒締切工を想定した縮尺模型および実物大規模の実験を行い，作業完了までに生じる現象や期待出来る減災効果，及び留意点を示した．河道水位が高い状況においてもブロック投入位置によらず投入個数に応じて氾濫流量が低減すること，投入速度を上げることでより効果が大きくなることなどが明らかとなり，現場条件に応じてブロックを投入可能な地点・方法で早期に着手することで，完全に破堤開口部を締め切ることが出来なくとも被害軽減につながる可能性を示した．doctoral thesi
Snow surveys of central and eastern Hokkaido from 2014 to 2018, and meteorological elements affecting snow grain type
Get PDF北海道の道央・道東地域の積雪分布の年次変動と大雪時の積雪特性を把握することを目的に，毎年同時期に同じ場所での調査を実施した．本研究は2014 年〜2018 年の5 冬期に北海道の32 地点で実施した広域積雪調査結果を取りまとめ，積雪特性と気象要素との関係を分析した．各冬期の気象は，積雪の高さや層位，雪質に現れていた．2014 年と2018 年は冬型の気圧配置が続き，道央地域が大雪
でしまり雪やざらめ雪が主体に，道東地域は少雪で下層にしもざらめ雪が発達していた．2015 年はオホーツク海側と根釧台地で大雪となった．2016 年と2017年は少雪で，特に2017年は全観測地で積雪の高さが100 cm 未満だった．積雪の高さと積雪水量の関係は，既往研究とよく一致し，両者の直線関係から導出した全層平均密度には道央と道東の地域差が現れていた．石坂（2008）による積雪地域の気候区分図の適中率は72% で，本研究はこの区分を概ね支持する結果になった．現地観測データを積雪モデルの精度向上につなげる目的で，複数の気象要素を説明変数とし重回帰分析による雪質推定を行った．その結果，各観測地の雪質を60% 以上説明できることがわかった．得られた経験式は積雪モデルの改善に有効である．journal articl
THE EFFECT OF RIVER CHANNEL SHAPE ON LEVEE BREACH PROCESSES
Get PDFIt is important mitigating flood damage by overflow from a levee breached. The mechanism of levee breach has not been clarified. This study aims to clarify the below point, the effect of river channel characteristics on levee breach processes by using a numerical model to simulate levee breaches based on results of the experiments. The results of the simulation are as follows: In the case of Froude number becomes larger, levee breach widening is dominant. In the case of Froude number becomes smaller, river bed erosion is dominant. And the phenomenon switches when the Froude number is about 0.5.journal articl
EXPERIMENTAL STUDY ON RAIN-ON-SNOW EVENTS IN SNOWY-COLD REGION
Get PDF降雨と融雪が重なる現象はrain-on-snow eventと呼ばれ，近年，世界各地で大規模な融雪災害をもたらしている．北海道においても，冬期におけるROS記録は各地に存在し，今後の降雨・積雪特性の変化が融雪災害に与える影響が懸念される．そこで，本研究では厳冬期のROS災害の特性を把握することを目的に室内水路実験を実施した．結果，融雪期の最高気温を想定した場合は，降雨に伴う積雪層のせん断強度低下と重量増加とが重なることで湿性雪崩が生じた．一方，本実験条件下で気温が10℃付近の場合は，降雨の影響は比較的少なく，雨は積雪層をゆっくり鉛直浸透し，流出した．ただし，降雨の影響は積雪層が新しい雪で構成されるほど大きく，北海道のような積雪寒冷地では，今後の気候変動に伴う積雪や降雨特性の変化が冬期の積雪層挙動や河川融雪災害に影響を与える可能性を留意する必要がある．In recent years, rain-on-snow (ROS) events has caused large-scale flooding disasters in winter all over the world. In Hokkaido located in the northernpart of Japan, ROS events also has been recorded in various places in the past and has been conserned to be increased in future due to the rise of temperatures over snowy-cold region. In this study, authors conduted flume experiments to understand the effects of rainfall on snow melt and snowmelt runoff, which affects ROS disasters during winter. The results showed that in the cases, estimated maximum temperature in winter (snow melting season), snow avalanches occurred due to the rainfall. In contrast, where the temperature is below 10 ℃, the rainfall slowly penetrate and formed the flow path at the bottom of snow layer, leading into an increase of 1.23 times of the runff discharge to the low channel path.journal articl
Hydrogen isotopic fractionation of ethane at the formation of crystallographic structure II mixed-gas hydrates
Get PDFWe report isotopic difference in ethane δD between gas and hydrate phases at the clathrate hydrate formation of ethaneargon systems. Ethane was concentrated into hydrate phase rather than argon. The hydrate of crystallographic structure II formed in the high concentration of argon, whereas the structure I appeared in the low concentration of argon. The isotopic difference in ethane δD between gas and hydrate phases changed according to the crystallographic structure, and the tendency was similar to the methane-ethane system. We proposed that the size of host cages affect the isotopic fractionation of guest molecules.journal articl
PMSGに基づく洋上ウィンドファームによるハイブリッド陸上電力システムの協調周波数制御
Get PDF北見工業大学博士（工学）This thesis deals with the coordinated frequency control method of hybrid onshore power system by using variable speed wind turbines with permanent magnet synchronous generators (VSWT-PMSGs) based offshore wind farm (OWF), which is connected to the main onshore grid through voltage source converter (VSC) based high voltage DC (HVDC) transmission system. Penetration of large-scale WF into the power grid has increased significantly and it inevitably leads to the retirements of conventional synchronous generators (SGs). Thus, the frequency fluctuations of the power system due to the high penetration of WF is a major concern. Therefore, to maintain the frequency stability of the power system WF is required to operate like conventional unit. They need not only supply power to the grid, but also need to damp frequency fluctuations. Therefore, the interaction of large-scale WF along with the existing power system is an important issue to be analyzed in order to minimize the frequency fluctuations.
Normally, VSWT-PMSG is preferable for OWF due to its gear-less feature, brushless operation, and lower losses compared to doubly fed induction generator (DFIG). Additionally, to integrate large-scale OWF into the onshore grid, VSC-HVDC transmission system is attractive and more preferable than high voltage AC (HVAC) transmission system from an economic and technical point of view. Normally, detailed model of VSC-HVDC is used in the simulation analysis, which requires, however, large computational time due to the switching phenomena of the power converters. Therefore, detailed model of the VSC-HVDC should be simplified in the analysis in order to diminish complexity and long simulation time. In this thesis, a simplified model of VSC-HVDC transmission system is developed for fast dynamic simulation analysis. Comparative analysis between the proposed simplified and detailed models of VSC-HVDC is also performed and presented. The simulation results show that the proposed simplified model of VSC-HVDC has sufficient accuracy for analyzing dynamic characteristics.
Usually, the characteristics of VSWT-PMSG based OWFs are different from that of the conventional power plants. To contribute to the primary frequency regulation in a similar way to conventional SGs, the VSWT-PMSG based OWF requires additional active power control loop and primary reserve. In this case, power reserve is possible by operating the VSWT-PMSGs at a reduced power level instead of maximum power point tracking (MPPT) mode which is called deloaded operation. Therefore, this thesis proposes firstly a primary frequency regulation method of hybrid power system by fixed deloaded operation of PMSG-based OWF. A new centralized droop control technique is also embedded for VSWT-PMSGs based OWF connected through VSC-HVDC transmission system to damp frequency oscillation of the main power grid in which a large-scale of WF composed of fixed speed wind turbines with squirrel cage induction generators (FSWT-SCIGs) and photovoltaic (PV) power station are installed. The centralized droop control technique is implemented with the dead band to limit the frequency variation within the permissible limit. Thus, better frequency regulation performance can be achieved.
The active power injected to the grid system from OWF is reduced by a fixed ratio at all times in the fixed deloaded operation, and hence, the energy loss become large. Therefore, this thesis also proposes secondly a centralized frequency control scheme with a novel variable deloaded operation for VSWT-PMSGs based OWF connected to the onshore grid through VSC-HVDC transmission system. This is one of the salient features of this thesis. A centralized droop controller with dead band is designed for VSWT-PMSGs to utilize this reserve power to suppress the frequency fluctuations of the onshore grid due to the installations of large-scale FSWT-SCIGs based WF and PV power station. The combination of variable deloaded operation and centralized droop controller can give better frequency regulation and decrease energy loss. To verify the effectiveness of the proposed control system, simulation analyses are performed on a multi-machine hybrid power system model. The simulation results reveal that the variable deloaded operation can decrease the energy loss compared to the fixed deloaded operation as well as suppress the frequency fluctuations in the same level as the fixed deloaded operation.
Simulations are carried out by PSCAD/EMTDC software. Real wind speed data and solar irradiance data measured in Hokkaido Island, Japan, are used in the simulation analyses to obtain the realistic responses. The standard IEEE nine-bus model is used to evaluate the performance of the proposed control strategies.
Considering all the features, it is concluded that the frequency oscillation can be minimized effectively by the proposed control strategies of PMSG.doctoral thesi
ディープラーニングを用いた振動データによる構造物の状態識別
Get PDF北見工業大学博士（工学）The deterioration of the aging infrastructures has become a global problem in recent decades, which threatens the public safety. To solve the above problem, researches on structural health monitoring (SHM) and structural damage detection (SDD) have been carried out all over the world. Researchers have made large amounts of efforts in the development of vibration-based SDD methods based on the theories of dynamics and signal processing.
In this thesis, an attempt on SHM has been made on a ballasts concrete railway bridge. By performing a series of vibration experiments, obvious variations on modal parameters have been found. The variations on the modal parameters show difficulties of SHM, which need to be overcome. The difficulties can be summarized as follows: (1) the effects of environmental variation and other uncertainties to the structural dynamic behavior, (2) low efficiency of using the large amounts of monitoring data.
In recent years, the rapid development of Deep Learning technology shows obvious advantages in many fields, such as object detection, medical science, and so on. Firstly, it is a pure data-driven method. By using Deep Learning technology, functions can be generated to link the input data to the results automatically, with no need of any domain knowledge. Secondly, large amounts of data can be used efficiently in the process of training a network.
Therefore, in this thesis, a vibration-based structural state identification method by using 1-D convolutional neural networks (CNNs) has been proposed. The proposed method aims to overcome the difficulties as introduced in the second paragraph by adapting the Deep Learning technology in the civil engineering field to solve the SHM problems.
By using the proposed 1-D CNNs, functions linking the raw vibration data and structural states can be established. Those 1-D CNNs are developed to identify tiny local structural changes, and are validated on actual structures. Databases of structural vibration response are established based on a T-shaped steel beam (in lab), a short steel girder bridge (in test field), and a long steel girder bridge (in service) to validate the performance of the proposed 1-D CNN. The complexities of data in above 3 databases increase progressively. The raw acceleration data are not pre-processed and are directly used as training and validation data. The well-trained CNNs almost perfectly identify the locations of the small local structural changes, demonstrating the high sensitivity of the proposed CNN to tiny changes in actual structures. The capacity of determining the boundary between data in different structural states is also shown clearly.
Subsequently, to explore the mechanism of the proposed 1-D CNN, the convolutional kernels and outputs of the convolutional and max pooling layers are visualized and analyzed. The effectiveness of the CNN is also proved by visualizing the variation of data structure in each layer of the CNN by the T-SNE method.
Furthermore, to examine the capacity of identify untrained structural changes of the proposed CNN, robustness tests of the CNN models to locations of structural changes and temperature effect are carried out. The results show low capacity of the classification CNN model to identify local structural changes in untrained locations and temperature environment. Fortunately, the robustness to the temperature effect can be easily improved by expanding the training data acquired in diverse temperature conditions.
Finally, to improve the expression capacity of location and the robustness of the CNN to locations of structural changes, a regression CNN model is proposed with the updated encoding of the label and the output layer of the CNN. Comparing to the classification CNN models, higher robustness is obtained in the regression CNN model. Moreover, a deep network with multi-convolution blocks and multi-task outputs is proposed to further improve the robustness of identifying local structural changes in untrained locations. The results show obvious increase in the accuracies of the network to identify untrained local structural changes.
Overall, the expected contributions will be two-folds. For academy, the results of the study demonstrate the feasibility and rationality of using Deep Learning technology to solve SHM and SDD problems in civil engineering field. The potential of developing new Deep-Learning-based SHM and SDD schemes are also shown. For the society, the proposed research will boost the development of technology that guarantees human’s daily safety.doctoral thesi
SPRによる硫酸化糖鎖とHIVオリゴペプチド間の相互作用メカニズムの解析
Get PDF北見工業大学博士（工学）Sulfated polysaccharides have specific antiviral activities, which biological mechanism is assumed to the electrostatic interaction between (+)-charged virus surface glycoproteins and (-)-charged sulfate groups. For the elucidation of the mechanism, several oligopeptides referenced by the sequence of Human Immunodeficiency Virus glycoprotein 120 (HIV gp120) and hemagglutinin (HA) of influenza A and B were synthesized by a peptide synthesizer and the interaction with structurally distinct sulfated polysaccharides such as curdlan sulfate and dextran sulfate was analyzed by SPR.
In this study, three oligosaccharides were synthesized from the sequence of the V3 loop, C-terminus, and CD4 binding domain in the HIV gp120. Oligopeptide A from the V3 loop comprises 20 amino acids with seven positively charged lysine and arginine in the sequence. The basic amino acids were relatively dispersed along the sequence compared with that of oligopeptide B. Likewise, oligopeptide B from the C–terminus comprises seven lysine and arginine, also oligopeptide of Influenza A/Yamagata HA and Influenza A/Brisbane HA comprises 23 amino acids with eight positively charged lysine and arginine in the sequence. Oligopeptide C from the CD4 binding domain and Influenza B /Hong Kong from the HA comprises one lysine and next to the biotin. The biotinylated peptides were synthesized by a microwave assisted solid phase peptide synthesizer using Fmoc protected amino acids. The peptides were purified by RP-HPLC and identified the structure by using MALDI TOF MS. Peptides A and B from HIV gp120 were found to have interacted strongly with dextran and curdlan sulfates, however, the peptide C without positively charged amino acids showed no interaction. These results suggest that the interaction was due to the electrostatic interaction between negatively charged sulfate groups and positively charged amino groups of the peptides. The results of influenza HAs, influenza A (Yamagata and Brisbane) and B (Hong Kong) viruses, are also presented.
Curdlan and dextran sulfates were found to increase the interaction with increasing the molecular weights and degree of sulfation (DS), which were found to be important factors for the antiviral activity of sulfated polysaccharides. Based on the above, suggesting the antivirus mechanism of sulfated polysaccharides to be the electrostatic interaction of negatively charged sulfated polysaccharides and virus surface glycoprotein at the positively charged amino acid regions.doctoral thesi
MiNgMatch—A Fast N-gram Model for Word Segmentation of the Ainu Language
Get PDFWord segmentation is an essential task in automatic language processing for languages where there are no explicit word boundary markers, or where space-delimited orthographic words are too coarse-grained. In this paper we introduce the MiNgMatch Segmenter—a fast word segmentation algorithm, which reduces the problem of identifying word boundaries to finding the shortest sequence of lexical n-grams matching the input text. In order to validate our method in a low-resource scenario involving extremely sparse data, we tested it with a small corpus of text in the critically endangered language of the Ainu people living in northern parts of Japan. Furthermore, we performed a series of experiments comparing our algorithm with systems utilizing state-of-the-art lexical n-gram-based language modelling techniques (namely, Stupid Backoff model and a model with modified Kneser-Ney smoothing), as well as a neural model performing word segmentation as character sequence labelling. The experimental results we obtained demonstrate the high performance of our algorithm, comparable with the other best-performing models. Given its low computational cost and competitive results, we believe that the proposed approach could be extended to other languages, and possibly also to other Natural Language Processing tasks, such as speech recognition.journal articl
北見工業大学社会連携推進センター年報 第17号（平成30年度版）
Get PDF【巻頭言】
「新しい地域連携体制の構築」―三大学統合を見据えて―
社会連携推進センター長 有田 敏彦
１．平成30年度活動状況
１）事業計画及び事業報告
平成30年度事業計画…1
平成30年度事業報告…2
２）運営組織
スタッフ…5
客員教授…5
産学官連携推進員…6
産学官連携推進協力員…6
３）共同研究等
共同研究・受託研究報告…8
共同研究件数の推移…9
共同研究受入一覧表…10
４）産学官連携活動
交流イベント等出展状況…19
５）知的財産活動実績
発明届出・国内特許出願・国内登録特許件数…26
６）地域再生人材育成プログラムの推進
工学連携推進型地域6次産業人材育成事業…27
７）各種会議報告…32
８）活動日誌…35
２．付録
・センター関連規程
・技術相談申込書othe