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物質科学における時系列データの機械学習解析手法開発と応用：隠れマルコフモデルを用いた量子ドットおよび蛍光修飾DNAの蛍光時系列データ解析
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604号 学位授与年月日:令和7年3月25日thesi
Estimation of Image-Based End-Effector Approach Angles for Tomato Harvesting Robots
Get PDFWe propose a method to estimate a suitable approach angle for the end-effector of a tomato harvesting robot based on image data. Agricultural harvesting robots often face obstacles such as other fruits or stems around the target crop. Additionally, it is important to approach the target from a direction appropriate for harvesting, considering the shape of the end-effector. The proposed method uses a deep learning-based instance segmentation model to extract regions of fruits and stems, and estimates the suitable approach angle based on their positional relationships. We demonstrated the usefulness of the proposed method using an image dataset acquired in an actual tomato greenhouse.conference pape
Discovery of Novel Antimicrobial-Active Compounds and Their Analogues by In Silico Small Chemical Screening Targeting Staphylococcus aureus MurB
Get PDFMethicillin-resistant Staphylococcus aureus is a serious problem in healthcare due to its lethal severe infections and resistance to most antimicrobial agents. The number of new approved antimicrobial agents is declining, and combined with the spread of drug-resistant bacteria, it is predicted that effective antimicrobial agents against multidrug-resistant bacteria will be exhausted. We conducted in silico and in vitro discovery of novel antimicrobial small molecules targeting the SaMurB enzyme involved in cell wall synthesis in Staphylococcus aureus (S. aureus). We performed hierarchical structure-based drug screenings to identify compounds and their analogues using a library of approximately 1.3 million compound structures. In vitro experiments with Staphylococcus epidermidis (S. epidermidis) identified three compounds (SH5, SHa6, and SHa13) that exhibit antibacterial activity. These three compounds do not have toxicity against human-derived cells. SHa13 exhibited remarkable activity (IC50 value =1.64 ± 0.01 µM). The active compound was predicted to bind to the active site of SaMurB by forming a hydrogen bond with Arg188 in both R and S bodies. These data provide a starting point for the development of novel cell wall synthesis inhibitors as antimicrobial agents targeting SaMurB.journal articl
BLE Signal Reception and Localization Performance with Varying Receiver and Beacon Setups
Get PDFThis paper examines the performance of Bluetooth Low Energy signal reception for indoor localization by analyzing the interactions between gateways, beacons, and receiver placements. The study investigates the effect of different BLE beacon placements on signal strength and localization accuracy. It evaluates ten receiver ceiling-mounted and wall-mounted configurations, as well as five beacon body positions: shoulder, front pocket, back pocket, and wrist. A dataset comprising 2700 data points was collected and localization accuracy was assessed using a Radial Basis Function-based methodology. The results demonstrate that ceiling-mounted gateways offer more stable signal strength and enhanced localization accuracy compared to wall-mounted gateways. The findings highlight the significance of optimizing both gateway positioning and body placement to improve the performance of BLE-based indoor positioning systems.journal articl
Hydrogen production via water splitting using noble gas plasma-collisional splitting (NgPCS)
Get PDFNoble gas plasma-collisional splitting (NgPCS) is an emerging hydrogen production technology. Conventional methods, such as fossil fuel-based decomposition and water electrolysis (the latter requiring large amounts of electrolytes), have been widely used, but NgPCS eliminates the need for electrolytes, offering an eco-friendly and cost-effective alternative for producing hydrogen.journal articl
Space-Efficient B Trees via Load-Balancing
Get PDFWe study succinct variants of B trees in the word RAM model that require s + o(s) bits of space, where s is the number of bits essentially needed for storing keys and possibly other satellite values. Assuming that elements are sorted by keys (not necessarily in the order of their integer representations), our B trees support standard operations such as searching, insertion and deletion of elements. In some applications it is useful to associate a satellite value to each element, and to support aggregate operations such as computing the sum of values, the minimum/maximum value in a given range, or search operations based on those values. We propose a B tree representation storing n elements in s + O(s/lg n) bits of space and supporting all mentioned operations in O(lgn) time. Operations on integer-ordered keys and satellite values can be accelerated to O(lg n/lglg n) time if we use s + O(slglg n/lg n) bits of space. The time is retained for special kind of aggregate functions that can be computed bit-parallel in constant time. For integer-ordered keys, we can also compress the space s to match compression measures using difference encoding of the keys while retaining the operational time complexities. For the last enhancement, we allow us to pre-compute tables of o(n) bits.journal articl
食紅着色による土試料画像の輝度変化を用いた含水比推定に関する基礎的検討
Get PDF本研究では，土試料の含水比を簡便に推定する手法として，食紅による着色前後の撮影画像から着色による輝度ヒストグラムの変化率を求め，含水比との相関を分析した．撮影時の周辺光の影響を評価するため，遮光の有無による比較を行い，変化率が周辺光に大きく依存することを明らかにした．また，乾燥密度を一定とした実験では，変化率と含水比の間に明確な負の相関が得られた．一方で，乾燥密度を調整しない実験では，含水比の増加に伴って変化率に極小値が現れ，これは乾燥密度と保水性の関係を反映している可能性がある．これらの結果より，着色による変化率は土の乾燥密度や透水係数と密接な関係を持つことが示唆された．本手法は現場における省力的かつ迅速な含水比評価手法としての実用化が期待される．In this study, as a simple method for estimating the water content of soil samples, we calculated the rate of change in the brightness histogram due to coloring from images taken before and after coloring with food coloring and analyzed the correlation with water content. In order to evaluate the effect of ambient light at the time of shooting, we compared images taken with and without light shielding and found that the rate of change was highly dependent on ambient light. In addition, a clear negative correlation was obtained in experiments with a constant dry density between the rate of change and the water content. On the other hand, in experiments without adjusting the dry density, a minimum value appeared in the change rate as the water content increased, which may reflect relationships with water retention or permeability. These results suggest that the change rate due to coloring is closely related to the soil's dry density and permeability coefficient. This method is expected to be practical for field applications as a labor-saving and rapid method for evaluating water content.journal articl
Toward Abnormal Activity Recognition of Developmentally Disabled Individuals Using Pose Estimation
Get PDFIn this study, we propose to optimize temporal parameters with pose estimation data of simulated abnormal activities of developmentally disabled individuals by incorporating behavior context to Large Language Models (LLMs). Facilities for the developmentally disabled face the challenge of detecting abnormal behaviors because of limited staff and the difficulty of spotting subtle movements. Traditional methods often struggle to identify these behaviors because abnormal actions are irregular and unpredictable, leading to frequent misses or misclassifications. The main contributions of this work is the creation of a unique dataset with labeled abnormal behaviors and the proposed application of LLMs to this dataset comparing results of Zero-Shot and Few-Shot. Our method leverages the context of the collected abnormal activity data to prompt LLMs to suggest window size, overlap rate, and LSTM model’s length sequence tailored to the specific characteristics of these activities. The dataset includes labeled video data collected for four days from five normal participants performing eight activities with four abnormal behaviors. The data was collected with normal participants to simulate activities, and no individuals with disabilities. For evaluation, we assessed all normal versus abnormal activities and per abnormal activity recognition comparing with the baseline without LLM. The results showed that Few-Shot prompting delivered the best performance, with F1-score improvements of 7.69% for throwing things, 7.31% for attacking, 4.68% for head banging, and 1.24% for nail biting as compared to the baseline. Zero-Shot prompting also demonstrated strong recognition capabilities, achieving F1 scores above 96% across all abnormal behaviors. By using LLM-driven suggestions with YOLOv7 pose data, we optimize temporal parameters, enhancing sensitivity to abnormal behaviors and generalization across activities. The model reliably identifies short, complex behaviors, making it ideal for real-world caregiving applications.journal articl