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小型水槽内における複数魚の3次元位置推定・追跡手法の提案およびラスボラ・エスペイの群れ形成の効果検証
Get PDF九州工業大学九州工業大学博士学位論文（要旨）学位記番号: 生工博甲第508号 学位授与年月日:令和7年3月25日thesi
Study on Reinforcing Effect of Gabion Wall Facing with Reinforcing Materials during Flooding Using Open-Channel Experiments
Get PDFBridges are important social infrastructure, and in particular, the stability of the back-fill behind the abutment determines the safety of the entire bridge. Recent climate change has increased the risk of flooding, and damage caused by back-fill erosion and collapse is increasing. The objective of this study is to elucidate the damage mechanism of the back-fill of bridge abutments during floods and to propose new reinforcement techniques. In the experiments, indoor open channel tests using a scaled model were conducted to verify the effectiveness of the Gabion Faced Reinforced Soil Wall (GRW), which is a reinforcement method integrating gabions and geosynthetics to reduce the collapse of the back-fill due to flooding. The result of the study showed that the GRW was effective in preventing the collapse of the back-fill due to flooding. As a result, the time until complete collapse of the back-fill was three times longer in the case where GRW was installed than in the case where no countermeasures were taken. This suggests that GRW may be effective during flood events. However, boiling due to changes in pore water pressure occurred inside the back-fill, resulting in progressive sediment discharge. In particular, the effect of the gabion installation geometry was observed, confirming that the corner design is important to control scour. This study experimentally verified the effectiveness of the reinforced soil wall and provided knowledge that contributes to improving the durability of abutment back-fill during flooding. In the future, quantitative evaluation will be conducted to establish a more practical design method.journal articl
Experimental Investigation of Mechanical Properties of Geomaterials with Varying Fine Fraction Contents
Get PDFThe strength, deformation, and hydraulic properties of geomaterials, which constitute embankments, vary with fine fraction content. Therefore, numerous research studies have been conducted regarding the effects of fine fraction content on the engineering properties of geomaterials. However, there have only been a few studies in which the effects of fine fraction content on the soil skeletal structure have been quantitatively evaluated and related to compaction and mechanical properties. In this study, mechanical tests were conducted on geomaterials with various fine fraction contents to evaluate their compaction and mechanical properties focusing on the soil skeletal structure and void distribution. Furthermore, an internal structural analysis of specimens using X-ray computed tomography (CT) images was conducted to interpret the results of mechanical tests. As a result, it was discovered that the uniaxial compressive strength increased with fine fraction content, and the maximum uniaxial compressive strength was observed at a low water content, not at the optimum water content. Additionally, the obtained CT images revealed that large voids, which could serve as weak points for maintaining strength, decreased in volume, and small voids were evenly distributed within the specimens, resulting in a more stable soil skeletal structure.journal articl
Practical Exercise on An Autonomous Driving System Using Mobile Devices and IoT Devices for An Agricultural Tractor
Get PDFThe current method of agriculture is expected to make sustainable production difficult due to the effects of a declining and aging workforce. To solve these issues, research and development of smart agriculture technologies, including automated tractor operation, have been underway. We have developed an autonomous driving system for a commercially mini-tractor using mobile and IoT devices to more facilitate the introduction of automated driving technology for tractors. In addition, the exercise was conducted for students to implement and operate this system with an aim of education for robotics engineers. This exercise consists of lectures and development exercises for the system. The demonstration results showed that the students' difficulty level was able to set appropriate difficulty. The results of the rubric also showed that the students improved their proficiency in the algorithms and programming of applications that are fundamental to autonomous driving systems.conference pape
The Proposal for Ceiling-Hanging Panels and its Impact on Cooling Efficiency
Get PDFThe study focused on air-conditioning status when different air-conditioning loads occur in a single space to achieve cooling that is not separated by walls in an office building. In this case, whether all or only some of the air-conditioning units are operated, the problem is that the air-conditioning system blows air into zones that do not require cooling. To resolve this inefficiency, the study focused on the circulating air flow generated by the interchange of supply air and return air from the air-conditioning system. As a solution to trap air flow from an air-conditioning unit into a zone that requires cooling, a method for vertically installing panels on the ceiling is proposed. The analysis was performed by Computational Fluid Dynamics analysis while changing the length of the ceiling-hanging panel length conditions (350 mm, 700 mm, and 1100 mm); the blowing angle from the air-conditioning unit (15°, 30°, and 45°); and the blowing direction from the air-conditioning unit (4 directions and 2 directions). The ceiling-hanging panels and partitions are installed between the target zone where the air-conditioning unit is operated and the non-target zone where the air-conditioning unit is not operated. Cooling efficiencies were 84.0% when both panels and partitions were installed and 82.8% when both were not installed. However, when only the ceiling-hanging panels were installed, the cooling efficiency was 89.9%. The cooling efficiency was improved by about 5.9% by simply installing the ceiling-hanging panels.journal articl
大学における情報基盤及び情報ネットワークのセキュリティ強化と運用に関する研究
Get PDF九州工業大学博士（情報工学）1 序論～大学における情報基盤と情報ネットワークに求められる機能や運用技術～| 2 キャンパス情報ネットワークの構造変更等によるセキュリティ強化| 3 フロー情報の活用による異常通信検出・通信監視の強化| 4 電子メールシステムのセキュリティ強化～クラウド移行と多要素認証～| 5 まとめ九州工業大学博士学位論文 学位記番号:情工博甲第406号 学位授与年月日:令和7年3月25日令和6年度doctoral thesi
Usp21 Knockout Causes Abnormal Lipid Metabolism in Mouse and Its Polymorphism Correlates with Hypercholesterolemia in Outpatients
Get PDFUsp21, a member of the ubiquitin protease family, plays a vital role in various biological functions. However, the effects of Usp21 dysfunction remain incompletely understood. In this study, we generated Usp21 knockout (KO) mice. Blood tests showed no impairment of liver function but did reveal elevated levels of total cholesterol (T-CHOL) and free fatty acid (FFA) in Usp21 KO mice compared to wild-type (WT) mice. Next, we performed RNA-sequencing (RNA-seq) to identify genes that Usp21 regulates. The results highlighted several candidate genes based on their biological relevance, and their expression levels were validated by RT-qPCR. The Usp21 KO mice exhibited significant elevations in the expression of the genes Fabp7, Nlrc5, and Ppargc1a, which play an important role in lipid metabolism, compared to WT. These data suggest that Usp21 may play roles in lipid metabolism in association with Fabp7, Nlrc5 and Ppargc1a. To clarify the involvement of USP21 in human hypercholesterolemia, we examined single-nucleotide polymorphisms (SNPs) around USP21 in non-hypercholesterolemic and hypercholesterolemic outpatients. We found that the rs11421 SNP downstream of USP21 was significantly associated with hypercholesterolemia. These data suggest that Usp21 plays a role in mice and human lipid metabolism and that its polymorphism may be a diagnostic marker for human hypercholesterolemia.journal articl
可変速駆動システムの放射ノイズ発生機構と規格試験における放射電界強度の推定手法
Get PDF九州工業大学九州工業大学博士学位論文（要旨）学位記番号:工博甲第612号 学位授与年月日:令和7年9月25日thesi
Biodegradable Tactile Sensors Using a Bioderived Ionic Liquid for Transient Ionics
Get PDFIonic skin is a fundamental platform for tactile sensors that utilize electrolytes as sensing components. Ionic liquids (ILs) are ideal for such applications because of their high ionic conductivities, wide potential windows, and negligible vapor pressures. However, their toxicity hinders their use in wearable, implantable, and environmentally sensitive devices. Herein, ionic gels are synthesized from a bioderived IL and comprise pyramidal microstructures that enhance their tactile sensing capability. These structures improve elasticity and reduce the intrinsic viscoelasticity of the gels. The optimized sensor exhibits two conductance sensitivities of 0.066 and 0.032 and capacitive sensitivities of 0.075 and 0.042 in the pressure ranges of 0–10 kPa and 10–50 kPa, respectively. It exhibits rapid response and relaxation times of 156 and 157 ms, respectively, and maintains sensing capabilities for more than 5000 mechanical cycles, with a change in the conductance of only 8.6%. The sensor degradation test revealed that the active components─the ionic gel and molybdenum (Mo) electrodes─degraded in phosphate-buffered saline within 133 days, whereas the substrate and encapsulation layer remained nondegradable under the tested conditions. These results demonstrate the potential of biodegradable, nontoxic tactile sensors prepared using bioderived ILs in healthcare monitoring, wearable electronics, and environmental sensing.journal articl