• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.162-169
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• 2000

This study was carried out to develop a continuously variable-speed transmission(CVT) for agricultural tractor. A full-toroidal CVT mechanism with four discs and six rollers was selected as a device for changing speed ratio continuously. In the step of system layout design, the sizes of roller cylinders and end-load cylinder, which were critical factors for controlling the variator, were designed. Also the control pressure range was designed to limit the contact pressure of variator. In order to make the maximum speed of vehicle as 30km/h, the planetary gear and the six pairs of gears were designed. Also the hydraulic clutch, silent chain, hydraulic manifold and electronic controller were designed. After the design, a prototype with CVT controller was developed and tested. The speed of vehicle was changed continuously to the speed set by driver and the settling time was about 0.52 second at the step-response test (reduction ratio of variator 2.0 to 1.0), which was acceptable as a response time for working with tractor.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.4
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• pp.23-32
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• 2022

Prototype UAMs are shown to us in the market. When the complete product is delivered to market, the efficiency of each UAMs can be compared by default. Before the complete product is shown to us, the comparative study on efficiency of UAMs is performed under the product cost estimation. The efficiency analysis result reveals that both of Lift & Cruise type and vectored thrust type show good efficiency at the initial stage of product. At the near terms stage, five years later from initial stage end, efficiency gets some change. Vectored thrust type of UAMs show best efficiency at the near term stage of product. Because UAMs will be used in urban area, Seoul is the place where the UAMs will be used first. The flying route from Seoul City Hall to Yongsan Park, National Assembly in Yeouido, and City Airport is no more than 10 km distance. For this short distance route, efficiency will make multi-rotor type UAM be prefered to other types. For long distance route or commuting route, life & cruise type and vectored thrust type of UAMs will be prefered on account of operational efficiency.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.7
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• pp.475-484
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• 2018

The propulsion control device of an electric railway vehicle is a key main component corresponding to an engine of an automobile, and a device for controlling this is a device called a GDU (Gate Drive Unit). Also, when the frequency of failure of the propulsion control system was analyzed, the nonconformity ratio of GDU was the highest. GDU was not able to access core technologies due to the introduction of foreign products, and there were general problems with overall maintenance activities due to discontinuation of GDU of the manufacturer. The GDU has reached the end of its life with 23 to 14 years of long-term use.In order to solve these problems, this study was designed to identify the proper life span by analyzing compatible GDU's acquisition and failure, and to improve the existing system of maintenance focusing on health inspection. Maintenance of the components with a short life span compared to the entire service life is essential. Most foreign parts introduced at the beginning of the construction are not replaced due to technical problems or long-term operation. However, due to the characteristics of railway vehicles with a long life span of more than 25 years, it is necessary to maintain them for a long period of time. The study should be more concrete and empirical. The replacement type GDU of capacitors was able to easily measure the life of the capacitance by removing the capacitor modules, measure the life span of each unit test, and accurately perform preventive maintenance of the capacitor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1244-1247
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• 2004

In the last year, the number of registered vehicles in Korea surpassed the 14 million mark, and increase in number continuously. Nowdays, this tendency has raised some problems inevitably in the view of expansion of ELV and earth environment pollution resulted from it. Currently, the domestic recycle rate of ELV is about 75％. the reason of the row rate of it is due to that dismantling company can not obtain the needed recycling technology. State of art for recycling technology of ELV in domestic & foreign was introduced.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.890-894
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• 2003

This paper discuss basic functional construction and plant layout of a ELV dismantling system that can maximize the reusability of tarts and the recoverability of materials by dismantling ELV rationally and efficiently. "Island" type was selected for the system configuration considering processing amount, economical efficiency, and effectiveness. The system is supported by the information system, and composed of dismantling stations and handling equipments. The layout of the stations was determined after simulation and optimization using commercial software package, Arena and OptQuest. The objective of the optimization was maximum profit while the system capacity is considered as constraint. The environmental load of ELV can be minimized when the composition and function of each station are embodied in detail and the system is interfaced with shredding operation.

• Resources Recycling
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• v.18 no.5
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• pp.3-11
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• 2009

Recently efficient recycling of natural resource has been raised many people's interest with global warming issue. This study is focused mainly on main content of automobile recycling regulation and current situation of each nations including EU which is firstly acted. Also we were considering for adequate way to make better resource recycling condition and reduce Environment burden.

• Proceedings of the KAIS Fall Conference
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• 2011.12a
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• pp.353-356
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• 2011

자동차 폐차사업자들은 대부분 소규모로 영세하게 운영되고 있으며, 비효율적인 폐차 프로세스로 인해 폐차 소유자는 물론 폐차처리장까지 불이익을 받고 있다. 이를 위한 폐차 시스템에 대한 연구가 국내외에서 활발히 진행되고 있다. 하지만 기존에 개발되어진 폐차 해체시스템의 경우는 국내 폐차업계에 적용하기에는 경제적, 실용적으로 현실성이 부족하다. 따라서 본 연구에서는 폐차에 대한 효율성 극대화와 범용성 확보를 위해 시뮬레이션을 통한 폐자동차 해체시스템을 개발하고자 한다. 시뮬레이션을 통한 폐차 해체시스템의 사용은 복잡한 공정 또는 시스템의 설계 및 운영결과에 대한 효율적 분석이 가능하며, 다양한 위치 및 작업내용을 변경시켜 여러 대안을 마련할 수 있고, 이에 대한 결과를 미리 알아봄으로써 적은 시간과 비용으로 현장상황에 맞는 적절한 시스템을 구축할 수 있게 해주는 장점이 있다. 또한 최적 해체경로 시스템의 적용으로 시스템의 효율을 향상시켰다. 개발되어질 시스템은 높은 범용성 및 유연성 확보로 국내 폐차 업계의 발전에 크게 이바지 할 것이다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1303-1308
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• 2006

지금까지 제조업체는 생산 및 물류 시스템의 효율성 증대를 통한 제품판매 증가에만 주의를 기울여왔다. 그러나 환경에 대한 관심이 높아지고, 관련 법규가 엄격해지면서 폐기물 처리와 재활용이 기업의 생존을 위한 중요한 과제로 떠오르고 있다. 자동차 제조업계에서 역시 폐자동차 재사용 및 재활용에 대한 연구가 진행되고 있으나, 한국에서는 자동차 산업의 외형적 성장과는 달리 이에 대한 시스템 구축이 미비한 상태이다. 본 연구에서는 폐자동차의 재활용에 관한 외국의 사례를 조사하고, 폐자동차의 회수 및 해체 촉진을 위한 바람직한 정부 정책 모델을 제시하려 한다.

• Resources Recycling
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• v.28 no.2
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• pp.23-30
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• 2019

An color sorting technique was introduced to recycle End-of-life automobile shredded bumpers. The color sorting is a innovate method of separating the differences in the color of materials which are difficult to separate in gravity and size classification by using a camera and an image process technique. Experiments were planned and optimal conditions were derived by applying BBD (Box-Behnken Design) in the reaction surface method. The effects of color sensitivity, feed rate and sample size were analyzed, and a second-order reaction model was obtained based on the analysis of regression and statistical methods and $R^2$ and p-value were 99.56% and < 0.001. Optimum recovery was 94.1% under the conditions of color sensitivity, feed rate and particle size of 32%, 200 kg/h, and 33 mm respectively. The recovery of actual experiment was 93.8%. The experimental data agreed well with the predicted value and confirmed that the model was appropriate.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.421-426
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• 2009

Recently, the design process for a railway bogie frame in Europe has been carried out according to the norm EN 13749. The activities in the norm EN shall demonstrate that the design of the bogie frame fulfills the acceptances of 4 steps of the program such as structural calculation, static tests, fatigue test and on-tracks tests. At the end of the acceptance program, the on-tracks tests have the aim to measure the real stress history generated in operation and to verify that they are reasonably next to those calculated and measured on the test rig. Therefore, in order to assure the safety of the railway vehicle, it is important to examined the durability of that under load histories measured from on-tracks tests. In this study, under variable amplitude loading based on the actual acceleration history, fatigue analysis of the welding bogie frame is investigated by using durability software. Moreover, the fatigue life of the frame under the loading in the norm EN fatigue test condition is evaluated and compared with the life under variable amplitude loading.