• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.540-542
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• 2014

This paper introduces main activities of ISO/TC 108/SC 3 and published standards. Two working groups (WG 1 and WG 6) have been orgnized to review and revise ISO standards, specifically related to measurement and calibration subjects of vibration and shocks. A new joint working group (JWG1) with IEC/SC 47E (Semiconductor acceleration calibration) has started to deal with calibration methods for analog and digital output MEMS accelerometers. Finally, Published ISO standards, technically super-visored by ISO/TC 108/SC 3, are listed in this paper to help readers understand their main contents.

• Economic and Environmental Geology
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• v.28 no.3
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• pp.279-286
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• 1995

The amount of the high level radioactive wastes in Korea will be increased up to 14,297 MTU about 2010 year. Most of countries adopt the concept of deep burial repository in high level radioactive waste disposal. Because the high level radioactive wastes are very toxic in biosphere and to human, the data verifing its never return to the biosphere are requisite for the disposal. Presently, the evaluating techniques for the high level radioactive waste disposal are not fully developed. Therefore, in order to dispose the high level radioactive wastes in proper time the R & D of it is urged in our country. The R & D and/or the international joint research programme for the disposal of high level wastes have already been proceeded. In our country no plan for its disposal has been prepared. It is the time that the direction of the R & D is to be discused seriously. The R & D for the disposal of high level radioactive wastes in Korea is believed to be focused on developing the pecular techniques such as in situ characteristics of groundwater flowage, and change of properties of in situ rock mass at thermal effects.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.91-98
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• 2011

Korea's aerospace industry tries to achieve the exports goal in 2020, 10 billion dollars, in accordance with the "Future aviation industry development master plan", but it's skill is still not keeping pace. To secure and improve the appropriate technology, it is desperately needed to cooperate with advanced countries or companies of aerospace industry, but they are liked to manage their technology transfer or demand tremendous high price. This study presents that Russia could be a another nation which is able to cooperation on aerospace industry. Although Russia had have superior technology in aerospace industry, they have lost the competitiveness on that field after the collapse of the Soviet Union. Now, they are trying to regain their original fame in the commercialized way. So, this study suggests practical ways which South Korea and Russia may be helpful each other based on experiences working together.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.85-86
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• 2008

케이블의 원가절감을 위해 절연체의 절연두께를 줄이거나 초초고압화가 되어 갈수록 절연성능의 신뢰성 향상이 한층 요구되고 있다. 이를 위해 케이블 및 접속함의 절연체 내에 각종의 결함이 어느 정도 절연성능을 떨어뜨리는지 정량적으로 파악하여 개선할 필요가 있다. 또한 완제품 내 잔족하고 있는 이물의 종류 및 위치를 알 수 있으면 생산공정 내에서 이물 유입 경로를 파악하여 이물이 유입되는 것을 차단할 수 있다. AC내전압 파괴시험을 수행할 때 설계치 보다 저전계에서 파괴될 경우 파괴공을 조사하여 원인을 규명하고자 하지만 국부적인 결함으로 인한 파괴는 결함부를 소실시키기 때문에 파괴공 및 주위의 절연체를 현미경으로 관찰하여도 찾기가 어렵다. 따라서, 전원을 고속으로 차단하여 결함부가 완전히 소손되는 것을 막고 PD발생 위치를 추정하여 결함을 확인하는 방법이 요구 되어진다. 이러한 시험 방법을 전구차단법 이라고 하며, 고도의 PD측정기술과 판정기술이 필요한 종합적인 기술이다. 본 논문에서는 PPD 기술의 핵심인 노이즈 제거 기술과 판별기술을 서술하고 실제 접속함(PMJ)에 적용하여 PPD 기술의 유효함을 증명하였다.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.265-266
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• 2011

본 연구에서는 유한요소 해석 방법을 이용하여 척추 퇴행성 질환을 가진 환자의 관절 불안정 모델을 개발 및 검증하였다. 관절 불안정 모델은 정상요추 유한요소 모델의 인대 및 협부를 결손시켜 개발하였으며, 요추 유한요소 모델의 제 5 요추체를 완전히 고정시키고 추적 경로 방향의 400 N의 압축력을 가한 상태에서 10 Nm의 굴곡과 신전 모멘트를 가하였다. 굽힘 및 신전 시 관절 불안정 모델들의 회전량이 정상의 요추 모델의 회전량에 비하여 크게 나타났다. 또한 굽힘 시 관절 불안정 모델들의 전위거리가 정상에 비하여 크게 나타났다. 본 연구의 결과는 척추 불안정성의 원인 및 기전의 이해뿐만 아니라 다양한 인체정보 콘텐츠 분야에 널리 활용될 수 있을 것으로 생각된다.

• Journal of the Korean Mathematical Society
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• v.38 no.4
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• pp.807-842
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• 2001

This paper summarizes recent development of analytical and algorithmical results for stationary FIFO queues with multiple Markovian arrival streams, where service time distributions are general and they may differ for different arrival streams. While this kind of queues naturally arises in considering queues with a superposition of independent phase-type arrivals, the conventional approach based on the queue length dynamics (i.e., M/G/1 pradigm) is not applicable to this kind of queues. On the contrary, the workload process has a Markovian property, so that it is analytically tractable. This paper first reviews the results for the stationary distributions of the amount of work-in-system, actual waiting time and sojourn time, all of which were obtained in the last six years by the author. Further this paper shows an alternative approach, recently developed by the author, to analyze the joint queue length distribution based on the waiting time distribution. An emphasis is placed on how to construct a numerically feasible recursion to compute the stationary queue length mass function.

• Journal of Applied Reliability
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• v.16 no.2
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• pp.125-133
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• 2016

Purpose: The purpose of this study is to evaluate durability of platform safety step system in railway. Method: We performed finite element analysis & durability analysis of platform safety step system with VPD (Virtual Product Development) techniques and examined the durability standard & qualification life through the rig test during no failure test time in reliability qualification test. We continued to test 1 million cycles in KRS (Korea Railway Standard) for system's robust design performance. Result: FEM analysis results are 14.9MPa & 14.7MPa of pin-joint, pivot and durability analysis result is above 1 million cycles. we calculated theoretically no failure test time 855,000 cycles and through the 1 million cycles durability rig test in KRS standard we confirmed product quality. Conclusion: This platform safety step system was designed very safe in terms of a mechanical strength & durability.

• Journal of Applied Reliability
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• v.9 no.1
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• pp.29-35
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• 2009

Due to the excellent durability of Timing Chain, it has been widely used for vehicle engine system. Unlike the timing belt, since the timing chain is operated with the metallic sprocket, the lubrication system is absolutely needed to get this system start. As frequently met at the field, the lubricant has a strong tendency to leak out from the engine due to its severe operating environment. In this paper, results of investigation for thermal movement of aluminum chain cover were described to maximize the sealing ability which is desperately needed at the development stage of engine. Based on these results, some ideas for reproducing the leakage phenomenon and solving methods were proposed.

• Journal of Korean Physical Therapy Science
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• v.8 no.1
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• pp.727-734
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• 2001

Contracture is defined as the lack of full passive range of motion resulting from pint, muscle or soft tissue limitationprolonged Pint immobilization will result in stress and stretch deprivation and gradual development of contracture. the tissue changes caused by immobilization may be categorized as cellular modeling, ground substance and collagen response, and tissue response. contracture can be divided into three categories according to the anatomical location of pathological changes :arthrogenic, myogenic, soft tissue contractures Therapeutic approach of contracture is thermal or cold agents application, stretch or restoration of length, traction, manipulation, mobilization positioning and restoration of function. The purpose of this article is to review current concepts of mechanical properties and synthesis of collagen tissue and the underlying pathomechanics as it relates to evaluation and treatment of contracture.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.1-6
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• 2008

In industrial fields, human works are being replaced by robots. However, as the use of robots is limited in the process industry where they are operated fixedly, humanoid robots with wide applications need to be developed. Currently a great deal of research is being conducted on humanoid robots with the object of replacing humans in the workplace. However, because of the lack of relevant hardware and difficulty in mechanical parts, only very simple and limited progress is being made. In an effort to overcome these limitations, the purpose of the present study is to develop a kinematical mechanism and a controller. To this end, master arms with 3 degrees-of-freedom for the shoulders and the arms were composed which were able to reproduce human-like motions by simulating the characteristics of joint variables and the trajectory of the end-effector.