• Journal of Korean Society of Transportation
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• v.34 no.4
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• pp.341-353
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• 2016

Highway is mainly in charge of middle-long distance of vehicular travel. Trip length has shown a growing trend due to increased commute distances by the relocation of public agencies. For this reason, the proportion of driver-driven accidents, caused by their fatigue or sleepiness, are very high on highways. However, existing studies related to accident prediction have mainly considered external factors, such as road conditions, environmental factors and vehicle factors, without driving behavior. In this study, we suggested an accident index (FDR, Fatigued Driving Rate) based on traffic behavior using large-scale Car Navigation path data, and exlpored the relationship between FDR and traffic accidents. As a result, FDR and traffic accidents showed a high correlation. This confirmed the need for a paradigm shift (from facilities to travel behavior) in traffic accident prediction studies. FDR proposed in this study will be utilized in a variety of fields. For example, in providing information to prevent traffic accidents (sleepiness, reckless driving, etc) in advance, utilization of core technologies in highway safety diagnostics, selection of priority location of rest areas and shelter, and selection of attraction methods (rumble strips, grooving) for attention for fatigued sections.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.166-173
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• 2006

This paper investigated strength of a bogie frame for Korean tilting train that is being developed in KRRI. In this study, static load tests based on Japanese Industrial Standard (JIS) were performed. In order to simulate vertical and lateral components generated by tilting link mechanism, four hydraulic actuators were used. The eight load cases such as vertical, lateral, traction, braking and driving gear loads were applied for evaluation of the strength of bogie frame. The stresses measured at the stress concentration points were assessed using Goodman diagram. From the experimental results, structural safety of the bogie frame could be ensured.

• Journal of Advanced Marine Engineering and Technology
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• v.15 no.2
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• pp.44-52
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• 1991

The crankshaft system of engine is a complex vibratory object and its vibration modes are consisted of torsional, axial and their coupled vibration. Among them, the torsional vibration causes engine noise as well as serious fatigue faillures of crankshaft. If the troules of noises and crankshaft strength are forecasted by torsional vibration calculation in the design atage of crankshaft, the torsional damper is adopted as the final countermeasure. In this paper, some computer program to calculate crankshaft torsional vibration of engine are developed and with developed programs, an efficient rubber-viscous damper for automobile and with developed programs, an efficient rubber-viscous damper for automobile engine is designed and manufactured, and then it is fitted on the actual automobile engine to confirm its calculated efficiency. By comparing the measured result (with damper and without damper) with the calculated one, the reliability of developed computer programs and the performances of manufactured damper are confirmed.

• International Journal of Highway Engineering
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• v.20 no.2
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• pp.1-8
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• 2018

PURPOSES : In this study, design elements of rest areas for drowsy drivers are classified and appropriate criteria for each design element are presented. METHODS : By comparing and analyzing the design criteria for rest areas, the most appropriate installation criteria were suggested by considering the driving patterns of rest area users. RESULTS : As a result of the study, elements influencing the design of rest areas for drowsy drivers are suggested such as installation location and installation type. In addition, proper separation distance between resting areas was suggested considering vehicle flow, users' fatigue and physiological needs. Other criteria for rest areas were also suggested. CONCLUSIONS : Proper safety facilities were not installed in rest areas because appropriate criteria were not established. In this study, design elements were derived and installation criteria were designed so that rest areas could be used safely and conveniently.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.2
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• pp.56-59
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• 2006

A vibrational model of powder transfer equipment based on the lumped parameter method was developed, in which the operating motion consists of surging, bouncing, and pitching. After decoupling the equation of motion, the vibrational excitation source of the pitching motion was removed. So the designers are able to plan the optimum design to adjust the motion trajectory of the powder transfer equipment. That is, a procedure to adjust the motion trajectory of powder transfer equipment by changing design specifications such as the installation position, the direction of the motor, the driving speed, the mass unbalance, the stiffness coefficient, and the installation position of the support spring, is presented in this paper. The powder transfer equipment manufactured according to the results of this study did not suffer fatigue destruction, since the maximum stress on the basket structure was sufficiently small.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1012-1013
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• 2006

Marine technology must advance to meet the needs of a wealthier and more demanding public while at the same time provide greater environmental protection. Pollution noise and vibration is the specific issue being discussed in this paper Noise is of course due to vibration from high speed engines driving generators, entilators, winch and other gear, while underwater noise pollution results from the propellers and the resistance produced by the hull of the ship moving through the water. Vibration is also a factor in potential damage to sensitive electronic gear and metal fatigue. The issue of noise pollution does not cease when a vessel enters her berth and the main engines shut down. There is still the matter of ventilation and other mechanical factors at work to maintain a comfortable, efficient environment. We measured the noise level and vibration displacement in the training ship A-Ra at underway and Berth. The authors analyzed the frequency of noise and maximum vibration displacement in the position.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.785-791
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• 2002

본 연구에서는 자동차의 안락성에 큰 영향을 미치는 운전자세와 운전에 따른 피로도를 평가하는 방법에 대해 다루고자 한다. 이러한 피로도를 평가하기 위해서 EMG, ECG와 같은 생리신호를 이용한 정량적인 평가방법과 졸림감 주관적 피로도 등과 같은 정성적인 평가방법을 동시에 수행하였다. 본 실험은 실제 차량에서 동일탄 구간을(호남고속도로 대전-정읍)을 왕복 주행하면서 수행되었으며, 실험에 참여한 인원은 콩 6명이었다. 실험 결과 운전시간이 증가함에 따라 근육의 피로가 증가하는 것을 볼 수 있었으며, 동시에 졸림감 또한 증가하였다. 운전 자세에 따른 피로도의 평가 결과 졸림감이 중요한 요인으로 나났는데, 이는 안락한 운전자세 뿐만 아니라 안전한 운전을 위해서도 아주 중요한 요인이라 생각된다. 본 연구는 실제 차량을 통탄 피로도의 편가를 하는데 있어서 피로를 평가하는 방법에 대탄 가이드로써 그 역할이 중분하리라 생각이 되며. 무엇보다도 실제 차량에서 실험한 결과 샘플수가적기 때문에 객관적인 결과라고 말하기엔 어렵겠지만, 운전 자세에 따라서 유의한 자이를 보였다.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.120-122
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• 1993

This paper describes an improved FES system to restore paralyzed extremities in spinal cord injury patients. For composing stimulus pattern which is suitable for each muscle, electrical stimulus pattern creating system is also developed by using IBM-PC. In the improved portable FES system using V40 microprocessor, muscle fatigue can be decreased by selecting the stimulus frequency which is proper to the response characteristics of each muscle. Driving softwares for the portable FES system and the stimulus pattern creating system are programmed with assembler and C language. A multichnnel portable FES system is designed to minimize the sire and weight using a D/A converter and 32 channel multiplexer.

• Journal of Applied Reliability
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• v.17 no.2
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• pp.143-149
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• 2017

Purpose: In recent years, weight reduction for improving fuel efficiency of the vehicle and cost reduction have been developed. The structure of suspension link is widely used as a single plate press structure which can reduce process and weight compared to existing pipe welding method. However, it was found that the lifetime of a single plate press structure is determined by initial defects that occurred during initial manufacturing rather than fatigue damage caused by driving. Methods: I research the mechanism of failure phenomenon of the single plate press assist arm of rear wheel. In addition, I investigate durability effect parameters to determine the link lifetime in inserting bush into single plate press process through durability test. Conclusion: I discover significant durability effect parameter in inserting bush into single plate press process. It is expected that the durability can be improved by suggesting a bush inserting process inspection guide for similar suspension link like single plate press structure.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.350-355
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• 2004

Because the wage of railway crews is based on the duty hour rather than the working hour, most researches have focused on the balance of duty hour for the crews. In this paper, the structure of duty hour and its relationship to the crew wage are analyzed and some issues are identified. The duty hour consists of several different jobs which are weighed equally in calculating the crew's wage. Also, the difference between the working hour and duty hour is inconsistent with the train routes; i.e., the difference of a long distance train is larger than that of a small or medium distance train. To solve the problems, possible ways to link the duty hour to the wage better are proposed and exemplified