• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1685-1691
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• 2004

This paper describes the fault detection and failsafe logic to be used in an Electronic Stability Program(ESP). The aim of this paper is to prevent of erroneous controls in the ESP. Developed this paper introduces the fault detection logic and evaluation of residual signals. The failsafe logic consists of four redundant sub-models, which can be used for detecting the faults in various sensors (yaw rate, lateral acceleration, steering wheel angle). We present two mathematical residual generation methods : one is a method using the average value and the other is a method using the minimum value of the each residual. We verified a failsafe logic developed using vehicle test results also we compare vehicle model based simulation results with test vehicle results.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.774-779
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• 2004

This paper describes the fault detection and failsafe logic to be used in the Electronic Stability Program (ESP). The Aim of this paper is prevention of erroneous control in the ESP. This paper introduces the fault detection logic and evaluation of residual signals. Failsafe logic consist of four redundant sub-models and they can be used for the detection of faults in each sensor (yaw rate, lateral acceleration, steering wheel angle). We presents two mathematical residual generation method ; one is the method by the average value, and the other is the method by the minimum value of the each residual. We verify a failsafe logic using vehicle test results, also we compare vehicle model based simulation results with test vehicle results.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.401-405
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• 2003

This paper presents a design strategy of the dynamic simulator for the Korean tilting train. The tilting train simulator will generate the tilting motion to the lateral acceleration date obtained from the train dynamic analysis. The simulator will be composed of five components: (1) GUI control panel, (2) train dynamic analysis part, (3) tilting control part, (4) motion base with 6 electrical-motor-driven actuators and (5) visualization system. Using the simulator, we will verify the dynamic behaviors of the tilting train, interfaces among subparts and ride comfort before manufacturing of the tilting train.

• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.157-168
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• 2000

토류구조물의 안정문제로는 장단기적으로 정적인 경우와 동적인 경우, 그리고 지반의 동적 거동특성, 흙의 강도저하 등을 미리 파악하여 기술적인 대처를 할 필요가 있을 것이다. 본 연구에서는 실내 모형 실험을 통하여 구조물의 배면에 토성이 다른 일반모래, 표준모래, 점성토를 뒷채움하여 다짐없이 강사만 하고, 룰러다짐, 진동다짐을 하여 토피의 수평 진동거리를 길게, 짧게 그리고 중간으로 하여 강성벽체에 작요？는 수평토압에 대한 정적, 동적 특성을 규명하는 것이다. 모형 실험장치로는 실험대, 토조, 토압측정장치, 진동하중 발생장치, 진동측정장치, 강사기, 롤러 등을 설치하여 거리에 따른 병진운동으로 가속도와 수평토압, 수평토압계수, 전체토압, 토압의 작용점, 지진토압증분 증을 구하여, 실험결과와 기존 이론결과, 그리고 유한요소 해석결과와 비교 고찰하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.139-144
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• 2005

A vehicle cruise control algorithm using an Interacting Multiple Model (IMM)-based Multi-Target Tracking (MTT) method has been presented in this paper. The vehicle cruise control algorithm consists of three parts; track estimator using IMM-Probabilistic Data Association Filter (PDAF), a primary target vehicle determination algorithm and a single-target adaptive cruise control algorithm. Three motion models; uniform motion, lane-change motion and acceleration motion. have been adopted to distinguish large lateral motions from longitudinal motions. The models have been validated using simulated and experimental data. The improvement in the state estimation performance when using three models is verified in target tracking simulations. The performance and safety benefits of a multi-model-based MTT-ACC system is investigated via simulations using real driving radar sensor data. These simulations show system response that is more realistic and reflective of actual human driving behavior.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.23.1-23
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• 2001

The unmanned vehicle is composed of three parts the front & side sensor system for keeping the lane and avoiding obstacles, the acceleration & brake control system for longitudinal motion control, and the steering control system for the lateral motion control. Each system helps the unmanned vehicle of which should take notice of its location and recognize obstacles around the place by itself and make a decision how much fast to proceed according to circumstances. During the operation, the control strategy that the vehicle can detect obstacles and avoid collision on the road involves with vehicle velocity very much. Therefore, We have to define a traction system which is powered by DC motor so that, unmanned vehicle can control its velocity accurately. In this study, we find mechanical and ...

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.846-853
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• 2008

Maglev System is expected to be a new public transportation for future because of its special characteristics. Sleepers of railway role on transferring the lateral load to guideway for Maglev and controlling the distance between rails. Variation of distance of sleepers can affect dynamic responses for maglev guideway. In this paper, Daejon maglev guideway is analyzed to find proper tie spacing of a maglev system. The analysis included using a maglev trainload and also the dead load as the primary forces on bridges. Not only the dynamic behavior of bridges is investigated under sleeper conditions, but also impact factor about vertical displacement on the guideway is produced. This guideway is analyzed in four cases followed by changing spacing of sleeper and then obtained dynamic characteristics such as displacements, acceleration and impact factor by Finite Element Analysis.

• Journal of Drive and Control
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• v.18 no.4
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• pp.35-42
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• 2021

A personal mobility withstanding function for the disabled and vulnerable groups with difficulties in mobility was developed and structural and dynamics analysis was conducted. Personal mobility devices are a very helpful means of transportation for the disabled and vulnerable groups. In addition, the standing function allows individuals to perform a difficult task in while seated and offers a medical advantage to the user. In this study, a personal mobility device was designed and developed to help vulnerable groups and disabled people overcome limited mobility, and communicate with the general people at eye level through standing functions. Through structural and dynamic analysis, the structural safety, optimal speed during rotation, and lateral acceleration of the personal mobility device was analyzed. The analysis results are expected to contribute to the improvement of the users' convenience and stability of personal mobility.

• Physical Therapy Korea
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• v.25 no.4
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• pp.9-18
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• 2018

Background: Leg length discrepancy (LLD) leads to many musculoskeletal disorders and affects daily activities such as walking. In the majority of the population, mild LLD is a common condition. Nevertheless, it is still controversy among researchers and clinicians on the effects of mild LLD during gait, and available studies have largely overlooked this issue. Objects: The purpose of the present study is to investigate the effects of mild LLD on the gait parameters and trunk acceleration. Methods: A total of 15 female and male participants with no evidence of LLD of >.5 ㎝ participated in the present study. All participants walked under the following two conditions: (1) The non-LLD condition, where the participants walked in shoes of the same heel height; (2) A mild LLD condition induced by wearing a 1.5 ㎝ higher heel on the right shoe. The GAITRite system and tri-axial accelerometer were used to measure gait parameters and trunk acceleration. To compare the variation of each variable, a paired t-test was performed. Results: Compared to the non-LLD condition, step time and swing phase were significantly increased in the mild LLD condition, while stance phase, single support phase, and double support phase significantly decreased in the short limb (p<.05). In the long limb of the mild LLD condition, single support phase significantly increased, while swing phase significantly decreased (p<.05). Furthermore, significant decrease in the gait velocity and cadence in the mild LLD condition were observed (p<.05). In the comparison between both limbs in the mild LLD condition, the step time and swing phase of the short limb significantly increased compared with the long limb, while step length, stance phase, and single support phase of the long limb significantly increased compared with the short limb (p<.05). Additionally, trunk acceleration of all directions (anterior-posterior, medial-lateral, vertical) significantly increased in the mild LLD condition (p<.05). Conclusion: The results of the present study demonstrate that mild LLD causes altered and asymmetrical gait patterns and affects the trunk, resulting in inefficient gait. Therefore, mild LLD should not be overlooked and requires adequate treatment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.121-128
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• 2020

The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker-Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.