• 한국재료학회지
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• 제5권1호
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• pp.75-86
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• 1995

현재 계획중인 항공우주상업과 관련된 부품을 제조하여 생산하기 위해서는 사용된 재료가 설계요구조건에 적합한지가 평가되어야 한지만 국내에서는 항공기나 우주비행체를 개발한 경험이 없으므로 평가체제가 확립되어 있지 않다. 따라서 항공기 및 우주비행체의 내구성과 안전성확보에 필요한 재료의 인정방법을 정의할 필요가 있다. 본 기고에서는 항공우주 선진국에서 수행하고 있는 재료 및 가공공정의 합치성 결정에 필요한 특성시험을 고찰하고, 우주환경에 의한 재료특성 변화와 항고기용 복합재료 평가의 예를 제시하여, 국내의 항공우주용 재료 평가체제 확립의 기초가 되도록 하였다.

• Structural Engineering and Mechanics
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• 제20권3호
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• pp.313-334
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• 2005

The paper presents a new approach for the analysis of slope stability that is based on the numerical solution of a differential equation, which describes the thrust force distribution within the potential sliding mass. It is based on the evaluation of the thrust force value at the endpoint of the slip line. A coupled approximation of the slip and thrust lines is applied. The model is based on subdivision of the sliding mass into slices that are normal to the slip line and the equilibrium differential equation is obtained as the slice width approaches zero. Opposed to common iterative limit equilibrium procedures the present method is straightforward and gives an estimate of slope stability at the value of the safety factor prescribed in advance by standard requirements. Considering the location of the thrust line within the soil mass above the trial slip line eliminates the possible development of a tensile thrust force in the stable and critical states of the slope. The location of the upper boundary point of the thrust line is determined by the equilibrium of the upper triangular slice. The method can be applied to any smooth shape of a slip line, i.e., to a slip line without break points. An approximation of the slip and thrust lines by quadratic parabolas is used in the numerical examples for a series of slopes.

• 품질경영학회지
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• 제44권2호
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• pp.451-466
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• 2016

Purpose: This study was to identify customers' demands in railway services system and then to seek the way to satisfy the customer expectations. Methods: We suggest a Quality Function Deployment(QFD)-based approach comprised of three stages. In first stage, SERVPERF survey was carried out to assess current positions of customer expectations in the market. Then, factor analysis was incorporated into SERVPERF to classify customer expectations for the house of quality. In the second stage, the analytic network process was used to prioritize the importance of the customer attributes. Finally, QFD was performed utilizing customer attributes and their weights. Results: The QFD identified the most important customer expectations as: accident prevention, swift reaction to accident, on-time arrivals and departures of the train. It also shows that driving capability, equipment for safety, and training for disaster are the most critical technical requirements. Conclusion: The results are useful for identifying the customers' demands in railway services systems, and they can contribute to the service quality and customer satisfaction.

• 항공우주산업기술동향
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• 제6권2호
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• pp.154-160
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• 2008

항공기의 개발에 있어 비행시험은 통상적으로 크게 민간용과 군용의 두 분류로 나눌 수 있다. 민간용 항공기의 비행시험은 해당 정부의 감항당국에서 제시하는 안전/성능 요구도를 항공기가 충족하는지 여부를 개발자가 확인하는 것이다. 이에 반해 군용항공기의 비행시험은 소요제기를 한 해당 정부의 요구도를 항공 기기가 충족하는지 여부를 개발자의 사전점검(DT: Developmental Test) 이후에 정부의 독립적인 평가팀에 의해 Operational Test(OT)가 수행되어 최종적으로 확인하는 과정으로 진행된다. 이 논문에서는 민수용 항공기와 군용항공기 각각의 목적상 추진되던 인증업무가 비용의 효율성 제고, 민간항공기의 군용화 추세에 따라 민간항공기 인증방안을 사용해 군용항공기의 감항인증을 추진하는 선진국의 최신동향을 살펴보고 국내의 여건 및 향후 발전발향을 제시하고자 한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.961-964
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• 2008

화재에 대한 안전성 확보는 ECC 등과 같은 신소재를 실제 구조물에 적용 또는 실용화하기 위해필요한 중요한 요소 중 하나이다. 본 논문은 콘크리트 구조물에 있어서 내화층을 ECC로 사용하는 공법에 대하여, 이러한 ECC가 규준에서 요구하는 내화성능을 만족하는지 여부를 실험적으로 검토하기 위한 것이다. 이를 위하여 구조물의 화재 온도조건인 HC 및 RABT 화재온도이력곡선을 적용하여 실험을 수행하였다. 실험결과 ECC는 폭렬 및 화재상태에서의 모체콘크리트에 열화가 발생하지 않았다. 또한 기존 콘크리트 및 내화소재와의 상대 비교에 있어서도 ECC가 가장 우수한 내화성능을 보이고있음을 알 수 있었다.

• 연구논문집
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• 통권27호
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• pp.57-73
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• 1997

The bogie between the track and the railway vehicle body, is one of the most important component in railroad vehicle. Its effects on the safety of both passengers and vehicle itself, and on the overall performance of the vehicle such as riding quality, noise and vibration are critical. The bogie is mainly consisted of the bogie frame, suspensions, wheels and axles, braking system, and transmission system. The complex shapes of the bogie frame and the complicate loading condition (both static and dynamic) induced in real operation make it difficult to design the bogie frame fulfilling all the requirements. The complicated loads applied to the bogie frame are i) static load due to the weight of the vehicle and passengers, ii) quasi-static load due to the rolling in curves iii) dynamic load due to the relative motion between the track, bogie, and vehicle body. In designing the real bogie frame, fatigue analysis based on the above complicated loading conditions is a must. In this study, stress analysis of the bogie frame has been performed for the various loading conditions according to the UIC Code 6 15-4. Magnitudes of the stress amplitude and mean stress were estimated based on the stress analysis results to simulate the operating loads encountered in service. Fatigue strength of the bogie frame was evaluated by using the constant life diagram of the material. 3-D surface modelling, finite element meshing, and finite element analysis were performed by Pro-Engineer, MSC/PATRAN, and MSC/NASTRAN, respectively.

• 한국군사과학기술학회지
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• 제12권3호
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• pp.259-265
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• 2009

In the traditional percussion locks of small arms, a firing pin is struck by a hammer rotating on a single center of rotation, which makes the percussion mechanism simple and reliable. In order to strike the firing pin by the hammer, however, the firing pin should be located within the radius of rotation of the hammer. As the distance between the striking point of the firing pin and the center of rotation of the hammer becomes longer, the radius of rotation of the hammer should also be increased, which results in the increase of the volume and weight of the small arms because the hammer needs the more space for its operation inside of the small arms. In this paper, a link type percussion lock was newly proposed in order to overcome the limitation of designing small arms when using traditional percussion locks, as mentioned above. The link type percussion lock was modeled by using multi-body dynamics software and designed to satisfy the requirements such as striking force level of the hammer exerting on the firing pin enough to detonate the percussion cap of ammunitions and the safety on the accidental drop. It was applied to the newly developed dual-barrel weapon system, in which the weight and overall length are important design factors, and verified by durability test and drop test on the ground.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 전기설비전문위원
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• pp.195-197
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• 2009

It is a proven fact with the opening of the Seoul metro line number 1 in 1974 traffic congestion on the roads has decreased and the efficiency of people transportation in general has greatly been enhanced in the downtown and surrounding areas of Seoul. Even today construction of new subway lines are under way and many more are being planned due to the easy access to stations, short waiting and average travel times, compared with personal vehicles, contributing to the efficiency of the public transportation systems that are linking the downtown areas and also the intercity systems in moving passengers during rush hour and times of special event. Since the labour costs of the train operator in any large city based subway system accounts for a major part of the operating costs per kilometer and to ensure cost efficient operations, especially during non-peak hours, it is necessary to implement an unmanned(auto-driven) subway system. In order to implement such a system it is imperative that the on-board and wayside signalling control systems be fully automated as well. Only through proper examination of safety procedures not only by the AUGT(Automated Urban Guided Transport)system but also by ail the international standards organizations involved can safely and stability be ensured.

• 대한인간공학회지
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• 제35권5호
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• pp.449-464
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• 2016

Objective: The objective of this study is to identify essential requirements of the instrument cluster's features and layout for elderly drivers through interview and paper prototyping. Background: Recent updates implemented in passenger vehicles require more complex information to be processed by drivers. Concurrently, a large portion of the US population, the baby boomer generation has aged, causing their physical and cognitive abilities to deter. Thus it is crucial that new methods be implemented into vehicle design in order to accommodate for the deterioration of mental and physical abilities. Method: Forty elderly drivers and twenty young drivers participated in this study. The test included three sessions including: 1) location value assessment to identify the priority of areas within the instrument cluster; 2) component value assessment to capture rankings of the degree of importance and frequency of use for possible instrument cluster components; and 3) paper prototyping to collect self-designed cluster with selection of designs for each component and location of features from each participant. Results: Results revealed differences in the area priority of the instrument cluster as well as the shape and location of component features for age and gender groups. Conclusion: The study provided insights on instrument cluster layout guidelines by proving elderly driver's mental model and preferred cluster design configurations to improve driving safety. Application: LCD-based vehicle instrument cluster design, with an adaptable feature configuration for cluster components and layouts.

• BMB Reports
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• 제47권4호
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• pp.179-183
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• 2014

Investigators planning to use animals in their research and the Institutional Animal Care and Use Committee (IACUC) members who review the research protocols must take personal responsibility for ensuring that they have the skills and knowledge to perform their duties, applying the Three Rs principles of Russell and Burch. The two Korean laws introduced in 2008 and 2009 regulating animal use for scientific purposes in line with the Three Rs principles have been revised a total of 11 times over the last 6 years. Both regulatory agencies, e.g., the Animal and Plant Quarantine Agency and the Ministry of Food and Drug Safety, provide regular training based on the legal requirements. Based on the amended Animal Welfare Act, the IACUC appointment framework has been upgraded: appointments are now for two-year terms and require a qualified training certificate issued by the Animal and Plant Quarantine Agency since 2012. The authors reviewed the current curricular programs and types of training conducted by the two governing agencies through Internet searches. Our Internet survey results suggest that: a) diversity should be provided in training curricula, based on the roles, backgrounds and needs of the individual trainees; b) proper and continued educational programs should be provided, based on trainees' experiences; and c) active encouragement by government authorities can improve the quality of training curricula.