• Journal of the Korea Society for Simulation
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• v.23 no.1
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• pp.11-20
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• 2014

In this paper, we analyze the performance and reliability of the next-generation KRTCS (Korea Radio Train System) network. The KRTCS has been designed to manage and control the overall status of trains including location, speed, stop position, door open/close status and interior monitoring and so forth. System faults of the KRTCS operation can lead to the disruption of smooth train flow, even to terrible traffic accident. Prior to installation we need to assure the reliability of the designed KRTCS system. For this purpose, we simulated and analyzed the KRTCS network using QualNet simulator, assuming the various environmental operation data of train flows and communication faults that can be found in real telecommunication networks.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.4
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• pp.171-178
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• 2021

Caravans are easily affected by external physical factors and often cause dangerous situations for passengers. Therefore, in order to secure the stability of the passenger, there is a need to develop a sway reduction device capable of preventing the sway phenomenon in advance. This paper aims to minimize the hitch angle between the tow vehicle and the caravan. Specifically, the initial instability of the caravan is detected through an IMU sensor mounted on each of the tow vehicle and the caravan, and a control value is calculated to reduce errors from the Hitch angle and Hitch yaw rate using a PID controller. Different braking torques are generated, distributed, and controlled on the left and right brakes of the caravan according to the calculated control value. It could be verified through the driving experiment that the hitch angle was decreased compared to the case where the performance of the sway reduction device was not controlled, and the transverse stability improvement rate was improved by 94.49% compared to before control.

• Journal of Intelligence and Information Systems
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• v.13 no.3
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• pp.101-117
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• 2007

In this paper, we propose a customized genetic algorithm (GA) to find the minimum-cost guideway network (GN) of personal rapid transit (PRT) subject to connectivity, reliability, and traffic capacity constraints. PRT is a novel transportation concept, where a number of automated taxi-sized vehicles run on an elevated GN. One of the most important problems regarding PRT is how to design its GN topology for given station locations and the associated inter-station traffic demands. We model the GN as a directed graph, where its cost, connectivity, reliability, and node traffics are formulated. Based on this formulation, we develop the GA with special genetic operators well suited for the GN design problem. Such operators include steady state selection, repair algorithm, and directed mutation. We perform numerical experiments to determine the adequate GA parameters and compare its performance to other optimization algorithms previously reported. The experimental results verify the effectiveness and efficiency of the proposed approach for the GN design problem having up to 210 links.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.109-118
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• 2008

This study analyzes the change of stability of embankment due to the construction of embankment combined used road with two different construction phases. The stabilities have been checked both in the phase of earth banking for a road construction and in the phase of the application of the traffic roads(DB-24). In both cases the factor of safety has been found higher than 1.3 which is the general criterion of the safety of an embankment. The results indicate that the safety of an embankment due to the construction of embankment combined use road is assured, and thus, it is thought that the construction of embankment combined use road can be considered for cutting down on expenses of construction sites for a road construction. However, the pre-examination of stability due to the construction should be carried out because it decreases the factor of safety of an embankment. From this study, it has been found that the factor of safety was dropped most when the water level rose in the transient flow. The result indicates that the stability analysis of a river embankment where the water level changes frequently should be carried out in the condition of transient flow. It is recommended that the inner side of an embankment should have a slope of 1:2 which is identical with the slope of the existing embankment. In addition, the factor of safety also can be decreased due to the traffic loads, and therefore, the effect should also be considered after the construction of embankment combined used road limiting the traffic loads.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.220-223
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• 2004

지금까지 배송에 관한 연구는 주로 최적화된 차량의 배송 경로의 생성에 있어서 계획 생성까지의 시간의 단축이나 경로계획의 안정성의 확보에 초점을 두었다. 그러나 고객의 높은 서비스 수준을 만족시키기 위해서는 다양한 요구 사항을 충분히 반영한 동적인 운송계획의 수립과 함께 배송 단계에서 빈번히 발생하는 다양한 예외상황에 대한 적절한 대처가 필요하게 되었다. 본 연구에서는 최적화, GIS, GPS, ITS, Mobile등의 기술을 이용하여 동적으로 변화하는 실시간 환경에서 높은 서비스 수준을 제공할 수 있는 적응 운송 시스템의 모습을 제시하고자 한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.190-198
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• 1997

Traction control systems are used to prevent the wheel slippage and to maximize the traction force. A new scheme of controlling the wheel slip during cornering by varying the slip ration as a function of the slip angle is proposed and dynamically simulated with the model of a front wheel driven passenger vehicle. Simulation results show that the proposed scheme is superior to conventional ones based on the fixed slip ratio during cornering and lane changes.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.282-291
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• 2000

In this paper, the dynamics of automated guideway transit vehicles with rubber tires are studied. Two different AGT models are considered: the bogie system and the steering system . It is found that the bogie system is stable at all possible operating speeds, whereas it is not true fur the steering system. To investigate the dynamic stability of steering systems, the critical speeds are investigated and the dynamics of the closed-loop steering control system are numerically simulated.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.527-532
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• 2014

본 연구에서는 사각 실린더로 근사된 차체 주위에 균일한 층류 유동이 흐를 때, 앞 사각 실린더의 후면에 나타나는 후류의 변화를 정상적인 관점에서 분석하였다. EDISON_CFD를 이용하여 앞 실린더와 뒷 실린더의 변화에 따른 공력계수를 확인하였다. 격자 분해능과 시간 간격에 따른 정확성을 분석하였다. 앞 실린더의 길이 변화, 두 실린더 간의 거리를 통해 나타나는 공력계수의 변화를 실제 상황에서의 운행 안정성 및 공기 저항에 대입하여 분석하였다.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.67-74
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• 1999

When high speed train meets sidewind, folwfields around the train is very complex. In this case, the force by sidewind has a bad effect on stability of train. We can observe that the flow separates, reattaches, and forms all unsteady vortex in the wake region behind tile structure. Such folwfield can be analyzed by $\kappa$-$\omega$ SST model, and we investigate the effect for various section shape of high speed train. So we acquire the result that as tile corner of train section is rounder, stability of train is better.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.510-516
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• 1998

Dynamic stability of a high speed train is very important. This paper presents a dynamic stability analysis of K-TGV using Vampire Program. The analysis of stability on this paper is performed in condition of track irregularity, curved track and strong gust. The critical speed of K-TGV is 140m1s, and it is stable when runs on 7000R(cant 150mm) curved track and on linear track with the body exerted 101kN lateral impulse force.