• 한국시뮬레이션학회논문지
• /
• 제8권3호
• /
• pp.67-76
• /
• 1999

The study of the optimization of operating policy of AGV system, which is used in many factory automation environments has been proceeded by many researchers. The major operating policy of AGV system consists of routing and scheduling policy. AGV routing is composed with collision avoidance and minimal cost path find algorithm. To allocate jobs to the AGV system, AGV scheduling has to include AGV selection rules, parking rules, and recharging rules. Also in these rules, the key time parameters such as processing time of the device, loading/unloading time and charging time should be considered. In this research, we compare and analyze several operating policies of multiple loop-multiple AGV system by making a computer model and simulating it to present an appropriate operating policy.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.1220-1226
• /
• 2008

A route control in railway is one of the very important system to operate a train. An efficient train route control assures to increase train operation performance with a same railway system. The erroneous route control can accompany serious accidents which occur train collision or derailment which provokes death. A Route control carries out exactly lest the accident should take place. An interlocking table is widely used for the exact route control. The table has the problem of its exactness proving because it has been established by experts. In this paper, We tried to formalize a route control using mathematical logic. A route consists of symbolized tracks, signals, switch and crossing. It represents as a set, respectively. We proposed route setting control logic, converted the elements to set logics and construct route logics with the set logics of the elements. Finally we proposed a model which presents a prototype routes and we proved the proposed logics using the proposed method.

• 로봇학회논문지
• /
• 제18권3호
• /
• pp.316-322
• /
• 2023

The increasing popularity of autonomous unmanned aerial vehicles (UAVs) can be attributed to their wide range of applications. 3D path planning is one of the crucial components enabling autonomous flight. In this paper, we present a novel 3D path planning algorithm that generates and utilizes curvature-based trajectories. Our approach leverages circular properties, offering notable advantages. First, circular trajectories make collision detection easier. Second, the planning procedure is streamlined by eliminating the need for the spline process to generate dynamically feasible trajectories. To validate our proposed algorithm, we conducted simulations in Gazebo Simulator. Within the simulation, we placed various obstacles such as pillars, nets, trees, and walls. The results demonstrate the efficacy and potential of our proposed algorithm in facilitating efficient and reliable 3D path planning for UAVs.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2022년도 춘계학술발표대회
• /
• pp.708-711
• /
• 2022

본 논문은 3D 프린팅 출력 성공률을 높이기 위해 GPU를 이용한 대용량 3D 메쉬 모델에 대한 병렬 자체충돌 검사 방법을 제안한다. 강인하고 견고한 자체 충돌 검사를 위해 분리축 검사, 삼각형-삼각형 교차 검사, 메쉬 연결성 검사, 대용량 메쉬를 위한 분할 처리 기법의 절차를 제안한다. 이러한 자체 충돌 검사를 빠르게 수행하기 위하여 GPU 기반 병렬처리 구현 방법을 제시한다.

• 천문학회보
• /
• 제46권1호
• /
• pp.58.1-58.1
• /
• 2021

At the University of Seoul, we are investigating the following topics in cosmology: comparing traditional clustering algorithms to our new Mulguishin algorithms, analysis of 2-body Fuzzy Dark Matter 2-body collision, 2- and 3-point clustering statistics and its dependency on the cosmological model, and dynamics of dark-matter halos around the large-scale filamentary structures. In the following sections we present a brief introduction to our studies.

• Educational Technology International
• /
• 제12권1호
• /
• pp.21-46
• /
• 2011

International virtual teamwork offers new opportunities for the professional development of teachers. In this paper, we examine the initial experiences in an ongoing international virtual benchmarking project coordinated by the Finnish Online University of Applied Sciences. What challenges does an international context present for project construction and collaboration? Data from five countries, in the form of participant reflections and researchers' observations, were analysed according to four types of barriers: language, time, technical and mental barriers. Initial data indicates that trust is an essential starting point, as there is neither time nor possibilities to build mutual trust by traditional means. Organisational confidentiality issues, however, can complicate the situation. The project introduces 'collision' as a method of professional development, in which physical and organisational borders are crossed and the skills and competencies needed in global learning environments are acquired.

• 로봇학회논문지
• /
• 제19권1호
• /
• pp.92-97
• /
• 2024

This paper provides a study of distributional perspective on reinforcement learning for application in mobile robot navigation. Mapless navigation algorithms based on deep reinforcement learning are proven to promising performance and high applicability. The trial-and-error simulations in virtual environments are encouraged to implement autonomous navigation due to expensive real-life interactions. Nevertheless, applying the deep reinforcement learning model in real tasks is challenging due to dissimilar data collection between virtual simulation and the physical world, leading to high-risk manners and high collision rate. In this paper, we present distributional reinforcement learning architecture for mapless navigation of mobile robot that adapt the uncertainty of environmental change. The experimental results indicate the superior performance of distributional soft actor critic compared to conventional methods.

• Earthquakes and Structures
• /
• 제26권1호
• /
• pp.1-15
• /
• 2024

Isolation technology has been proven effective in reducing the seismic response of superstructures, where most of the deformation is concentrated in the isolation layer. However, in cases of earthquakes with intensities surpassing the fortification level of the area, or severe near-fault earthquakes, the isolation layer may experience excessive deformation, resulting in damage to the isolation bearings or collisions with the retaining wall or surrounding buildings. In this study, a finite element model using ABAQUS is established and compared with experimental test results to deeply investigate the influence of limit devices on the isolation layer and its response to the superstructure. The findings reveal that a larger limiter stiffness and a smaller reserved gap can achieve a more effective limiting effect. Nevertheless, a smaller reserved gap and a larger limiter stiffness may result in increased response of the superstructure. Therefore, rational selection of the reserved gap and limiter stiffness is crucial to reduce the acceleration response.

• 자동차안전학회지
• /
• 제16권2호
• /
• pp.60-66
• /
• 2024

Computer simulation significantly reduces the high costs associated with actual crash tests and is expanding due to its ability to analyze various test results quantitatively that are difficult to measure in real tests. Research on evaluation technologies is limited according to the finite element analysis, which aims to replace structural verification testing. In this study, considerations for virtual crash tests were derived, and the validity of the zero-energy mode (hourglass mode) was analyzed as part of the considerations for validating the results of vehicle crash simulations. The study reflects on the considerations for virtual crash tests and the variation in hourglass coefficient values affects the occurrence of the hourglass mode. As the hourglass coefficient changes, the maximum hourglass energy reaches over 5% of the maximum internal energy, necessitating a conservative review. A comprehensive study of the maximum hourglass energy is required, considering additional analysis results for various models and collision conditions.

• Journal of the Korean Physical Society
• /
• 제80권
• /
• pp.117-122
• /
• 2022

The Belle II detector at the SuperKEKB e⁺e^- collider in Japan is designed for precise measurements of weak interaction parameters and new physics beyond the Standard Model; therefore, it requires very high instantaneous luminosity. To handle such high luminosity, the level-1 trigger system in the Belle II experiment is designed to efficiently trigger events of interest with the highest efficiency. Among many sub-detectors, track reconstruction of charged particles is performed using information collected from the central drift chamber. Therefore, the central drift chamber-based trigger plays a central role in distinguishing specific types of physics based on fast track reconstruction. To improve the longitudinal position resolution of a track vertex and for the fine-tuning of trigger signal timing, the time of the collision, which we call event time, is necessary. We developed an event time finding algorithm using the wire hit time information obtained from the central drift chamber and validated our algorithm through Monte Carlo simulation.