• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8700-8706
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• 2015

The first driving device of the power bogies for the Korean high-speed railway vehicle consists of the traction motor (TM) and the motor reduction gears unit (MRU). Although TM and MRU are the mechanically integrated structures, their time between overhauls (TBO) have two separate intervals due to different technical requirements(i.e. TBO of MRU: $1.8{\times}10^6km$, TBO of TM: $2.5{\times}10^6km$). Therefore, to reduce the unnecessary number of preventive maintenances, it is important to evaluate the optimal TBO with a viewpoint of reliability-center maintenance towards cost-effective solution. In this study, derived from the field data in maintenance, fault tree analysis and failure rate of the subsystem considering criticality of the components are evaluated respectively. To minimize the conventional total maintenance cost, the same optimal TBO of the components is derived from genetic algorithm considering target reliability and improvement factor. In this algorithm, a chromosome which comprised of each individual is the minimum preventive maintenance interval. The fitness function of the individual in generation is acquired through the formulation using an inverse number of the total maintenance cost. Whereas the lowest common multiple method produces only a four percent reduction compared to what the existing method did, the optimal TBO of them using genetic algorithm is $2.25{\times}10^6$km, which is reduced to about 14% comparing the conventional method.

• Journal of Biosystems Engineering
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• v.8 no.1
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• pp.9-16
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• 1983

This study was conducted to find out the effects of such parameters as specific draft resistance, slip rate, and fuel consumption rate on plowing performance in paddy fields spread with chopped rice straw. The plowing operation by an 8 P.S. power tiller was carried out in 6 different fields having the soil moisture content of 27~36 percent in dry basis in clay loam soil texture, and applying chopped rice straw of 10, 20, 30 and 60cm in length in the spring of 1982. The effects of soil hardness and moisture content on the plowing performance were also investigated. The results of the study are summarized as follows; 1. The minimum draft during the plowing operation was 110kg in the 30cm rice straw plot having the soil moisture content of 32 percent in dry basis. 2. The multiple regression equation of the specific draft(D) as a function of soil moisture content(M) and cutting length of rice straw(L) was obtained as follows. $D=14.1978-0.8565M+0.0661LxM-2.9685L+0.0133M^2+1.093L^2$ 3. In the 30cm rice straw plot with the soil moisture content of 32 percent in dry basis, the minimum specific draft resistance and the rate of slip were 0.35kg per $cm^2$ and 16 percent respectively. The specific draft resistance varied sensitively in accordance with the soil moisture content, and the slip rate of power tiller was dependent upon the cutting length of rice straw rather than the soil moisture content. 4. The highest plowing performance was 5.3 ares per hour at the soil moisture content of 35 percent and soil hardness of 10kg per $cm^2$. The relationship between the plowing performance and the soil moisture content was obtained by a quadratic equation. 5. The minimum fuel consumption rate in the plowing operation was recorded 6.5 liters per 10 ares in 30cm chopped rice straw plot with the soil moisture content of 32 percent in dry basis.

• Venture DIGEST
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• s.69
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• pp.12-13
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• 2005

세계적인 석학 피터 드러커는 우리나라를 기업가정신이 가장 왕성한 나라라고 칭찬한 바 있다. 하지만 국민소득 2만달러의 목전에서 겪은 외환위기, 내수침체, 청년실업난 등으로 10여 년 간 제자리걸음하고 있는 지금, 그 말이 참 무색하게 다가온다. 이 악순환의 고리를 끊기 위해 우리 경제 활성화의 견인차로 다시 벤처가 나섰다. 지금이야말로 우리 벤처인들이 위험을 무릅쓰고 포착한 기회를 사업화하려는 모험과 도전의 기업가정신으로 재무장하여야 할 때이다. 기업가정신은 돈을 벌기 위한 정신이 아니다. 주위 사람과 공동체를 중시 여겨 자기희생을 감수하는 결단이고, 상상하기 어려운 힘든 역경 속에서도 좌절하지 않고 죽을 힘을 다하는 도전이며, 탄탄대로를 거부하고 비바람 부는 날 풀이 무성한 인적 드문 길을 선택하는 모험이다. ‘자본이 없어서, 기술이 없어서, 인재가 없어서’일을 못하겠다고 조건을 탓하거나 주저하지 말자. “신에게는 아직 12척의 배가 있사옵니다”라며 백의종군하여 병사도, 배도, 무기도, 군량미도 없이 홀몸으로 대함대와 맞서 찬란한 승리를 거둔 이순신 장군을 되새겨보라. 우리 벤처인에겐 아직 혁신과 도전과 모험정신이라는 기업가정신이 있지 않은가. 하늘에 온통 구름이 끼여있고 천둥번개가 내리쳐도 여전히 구름 뒤에는 밝은 태양이 빛나고 있다. 우리 벤처인이 기업가정신을 놓지않고 이상을 위해 도전한다면, 곧 구름 뒤 태양은 모습을 드러내고, 그대 벤처인을 향해 찬란히 빛날 것이다. 벤처인이여! 벤처 재도약의 동력이 될 기업가정신으로 재무장하고, 두 발로 땅을 박차고 일어나 구름 위 이상을 향해 힘차게 도약하자.

• Convergence Security Journal
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• v.15 no.3_2
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• pp.77-82
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• 2015

IT convergence has been approached from national strategic dimension with an aim to drive forward technology development and industrial advancement in other fields by taking the IT to the next advanced level, and has been the focus of intensive investment of research resources. Against this backdrop, IT convergence has emerged as a cutting-edge convergence industry that helps spur development of new growth engine being pushed forward at inter-ministerial level, as well as help turn the mainstay industries into high value-added industries and create new IT industry. Health-related convergence services have shifted its focus towards the exercise/sports and rehabilitation-oriented entertainment experiential industry away from conventional disease prevention and control-centric treatment/therapy technology industry. Thus, this study was intended to examine the trends of IT convergence technological development related to health exercise and present recommendation on the future course for development of major technologies and advancement of convergence industry, given the importance assigned to IT convergence.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.182-185
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• 2011

본 논문에서는 국내 고속철도 차량 즉, 경부고속철도를 운행하는 KTX, KTX산천 그리고 현재 개발중인 HEMU400x을 대상으로 운행속도 및 운행패턴에 따른 열차 소비전력을 분석하였다. 이를 위해, 선로조건을 고려한 차량의 운전속도 조건과 운행시간,소비전력 등을 예측하기 위한 TPS(Train Performance Simulation)프로그램을 이용하였다. 열차운행 시뮬레이션을 수행하기 위해선 차량, 선로, 속도의 기본 데이터를 필요로 한다. 차량에 대한 데이터는 차량의 최고속도, 제동성능, 견인력 등의 기본 성능과 열차편성에 따른 중량, 길이, 동력차량형식, 열차주행저항등에 대한 제원을 요한다. 선로데이터는 운행시간 예측을 대상으로 하는 선로에 대한 거리별 구배 및 선형, 정거장 위치 및 정차시간에 대한 데이터이다. 속도조건은 구배 및 곡선에 대한 선로제한속도로, 선로데이터와 연계하여 각 선로위치별 차량의 제한속도로 이용된다. 본 논문에서는 경부고속철도 구간에서 운행하는 고속차량 3가지를 대상으로 증속에 따른 전력소모량을 비교하였다.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.1
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• pp.62-70
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• 2003

Purpose: We examined the kinematics and kinetics of the shoulder in youth baseball pitchers in light of the mechanisms of development of little league shoulder and humeral retrotorsion. Materials and Methods: The joint kinematics and the net force and torque acting on the humerus were calculated in fourteen youth pitchers throwing in a simulated game. Results: The major force component acting on the humerus was a tensile force of 378$\pm$81 N that peaked just after ball release. The predominant torque on the humerus was an external rotation torque about the long axis of the humerus. This torque reached a peak value of 35.3$\pm$6.7 Nm about 73$\%$through the pitching motion. This torque is approximately 66$\%$ of the torque required to fracture of the adult humerus. Conclusions: The direction of the humeral torque was consistent with the development of increased humeral retrotorsion in the throwing arm. Shear stress arising from the high torque during the late cocking phase likely leads to deformation the relatively weak proximal humeral epiphysis. The external rotation torque applied to the humerus during the pitch also agrees with the proposed mechanism for development little league shoulder, which has been hypothesized to be due to rotational stresses acting on the epiphysis during the throwing motion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.493-501
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• 2016

In this study, core technologies of a traction system on a mountain tram operating on the track of mountain road full of sharp curves and steep gradients were developed. In domestic mountain resort areas, sometimes the transportation service is not provided in winter because of ice and heavy snow on roads, so a mountain railway service independent of the climate and geographic conditions is needed. A traction system was designed taking into account of the power of a traction motor to climb the gradient of 120 ‰, which is common in domestic mountainous areas. and power transmission system was designed to consider the installation space for the traction system. In addition, a reduction gear and a propeller shaft were developed. An elastic pinion was developed and applied to the rack & pinion bogie system for steep gradient so that noise and vibration generated by contact between the steel gears could be reduced. Impact comparison tests showed that the vibration level of the elastic pinion is one-third lower than that of previous steel pinion. Independent rotating wheels and axles were developed for the bogie system to operate on the sharp curve of a 10 meter radius. In addition, the band braking system was developed to enhance the braking force during running on the steep gradient. A test for the braking force showed it exerts the required braking force. The performance of the developed core components were verified by the tests and finally they were applied to the bogie system running on the track of steep gradient and sharp curve.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.17-17
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• 2003

1960년대 경제개발 5개년 계획의 시작과 함께 우리나라 과학기술의 발전을 위한 투자가 본격화되었고, 과학기술 혁신이 정부정책의 가장 중요한 시책으로 부각되었다. 지난 40 여 년간 우리나라 과학기술은 선진기술의 모방에서 출발하여 효율적으로 단계별 성장을 거치면서 2000 년대에는 세계수준의 지식 및 기술을 창출할 수 있는 토대가 마련되었다. 본 발표에서는 한국과학기술의 현주소와 향후 전망을 분석하여 국내 연구개발의 방향을 조명해 보고자 한다. 1982년 특정연구개발사업을 시작으로 국가적 차원에서 목표설정 및 연구개발 자원을 전략적으로 집결하여 다양한 국가 연구개발 사업들이 수행되어 왔다. 그 후 20여년이 지난 현재 20개 부처에서 200 여개의 국가 연구개발사업이 추진되고 있으며, 이러한 연구개발사업의 성과로서 DRAM, TFT-LCD, CDMA 등 첨단 분야에서 세계 최고 수준의 국제경쟁력을 갖춘 기술들이 다수 확보되었다. 주력 산업인 IT산업, 자동차, 철강, 조선, 섬유 등도 기술혁신에 의한 국제 경쟁력 강화로 수출이 확대되면서 우리 경제의 견인차 역할을 하고 있다 최근 10년간 연구개발 투자규모는 3배 이상 증가하여 2000년 기준으로 세계 8위의 투자규모를 달성하였으며, 민간의 연구개발 투자 비중도 크게 늘어나 민간주도형 연구개발체제로 전환되게 되었다. 2001년에 이르러서는 총연구비 투자규모가 15조 이상으로서 이는 전체 GDP의 ∼3% 에 해당되는 수치이며 선진국 수준에 육박하고 있음을 짐작 할 수 있다. 지식기반사회를 선도하여 국가 경쟁력을 높이기 위해 정부는 연구개발 투자를 계속 확대할 정책을 시도하고 있으며 창의적 과학기술인력의 양성 체제 구축 및 효율적인 활용에도 적극 투자하고 있다. 과학기술부는 과학기술혁신의 중추적 역할을 담당하고 있으며 현재까지 20,000여개이상의 과제를 수행하여 국가경쟁력 강화에 크게 기여하여왔다. 정부는 국내외 과학기술 환경변화가 심한 21세기를 맞이하여 새로운 기회와 도약을 위하여 과학기술 중심국가 건설이라는 새로운 비전을 제시하게 되었다. vision 2025를 통해 2025년까지 21세기 첫 4반세기 동안 과학기술 경쟁력을 세계적인 수준으로 끌어올려 과학기술에 기반을 둔 선진국 진입을 실현하고자 다양한 정책적 대응을 물색하고 있다. 세계 시장규모, 전략적 중요성 등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.25-32
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• 1977

This experiment was conducted in order to find out the drawing performance of a two-wheel tractor under different levels of the soil moisture and hardness, so as to obtain some basic data for improving their drawing performance. With fairly homogeneous soil, 5 levels of soil moisture contents (8, 13, 17, 20 and 23%) and 3 levels of soil hardness (0 , 2 and 4kg/$cm^2$) were selected for this experiment.The summerized results are as follows ;1. The draft force, on the hard soil (hardness ; 4kg/$cm^2$), had a distinct tendency to decrease with the increasing soil moisture. On the medium soil (hardness ; 2 kg/$cm^2$), and the soft soil (hardness ; 0kg$cm^2$), the draft force showed the highest when the moisture contents were within the range of 16-19%.But the maximum draft force, on the soft soil, was higher than that on the medium soil by 10 %. 2. The driving axle torque increased with increasing soil by 10 %. 3.The values of horizontal distance between the soil reaction point and axle shaft were within the range of 0~10cm , and it had the tendency to increase with the increasing soil moisture. Also, it s value was the largest on the hard soil and the smallest on the soft soil. 4.The tractive efficiency decreased with the increasing soil moisture. On the hard soil, the average value of tractive efficiency was higher than that on the medium soil by 19.0% and that on the soft soil was lower than that on the medium soil. 5.The traction ratio were within the range of 30 ~45%, and their changing tendency with respect to the soil moisture was similar to that in the case of the draft force. 6. The travel resistance ratio tended to increased with increasing soil moisture, and the highest value was found on the soft soil, and the lowest on the hard soil.

• Resources Recycling
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• v.19 no.4
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• pp.3-12
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• 2010

Countries which have a lot of metal resources are weaponizing metal resources such as supply limitation, high price sale. It's necessary for us to establish the countermeasure for recycling of used metal resources on a government basis. Ministry of Environment has established and announced the project for finding and reuse the hidden metal resources as pan-government department pass the Cabinet meeting at September 22, 2009. This countermeasure, 10 years project, is classified into 2 steps. Aim of this project is advance of the recycling technology and industry, achievement of recycling rate, 75%, improvement in adverse balance of trade, 1.25 billion US$.