• 전기학회논문지
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• 제65권7호
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• pp.1303-1310
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• 2016

The track circuit carries out a train detection using a electrical closed loop, and incidentally it detects the rail rupture using the track circuit current flowing rail. However, in the case of the axle counter or the Radio based train control system, it requires a new way for detecting the rail rupture because of not using the track circuit. To solve this problem, it periodically checks non-steady state of rail by the track inspection car. but real-time detection of the rail rupture is impossible. Therefore, this paper analyzed feasibility to realize a real-time detection of rail rupture by using the return current.

• 한국농촌건축학회논문집
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• 제18권1호
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• pp.11-18
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• 2016

The purpose of this study is to analyze the characteristics for the needs of rural residents and return farmer on rural rental housing. Through these rural rental housing as it wants to improve the living environment of rural areas. Housing problems of rural areas is one of the important factors that determine the quality of life in rural areas. Despite many rural development program it has been deteriorating housing conditions in rural areas. The purpose of this study aims to find the required characteristics of the rural residents and return farmer for rental housing system introduced in rural areas. As research methods, the survey it was required to rent the properties rural residents and expectant return farmer. The main analysis results are summarized as follows. First, expectant return farmer than rural residents are more flavors of rental Residential high. Second, rural residents prefer ratio was higher this apartment, expectant return farmer appeared to prefer the house. Finally, rural residents may prefer concrete homes, expectant return farmer appeared to favor the wooden houses. The results of this study can be a basis for effective strategies for future rural rental housing. More sustainable in the future, including the analysis of various parameters in progress by being linked to policy measures that will be provided. This study aims to be the foundation of sustainability in rural rental housing policy.

• 전기학회논문지
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• 제67권4호
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• pp.512-521
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• 2018

Islands that is far away from onshore have used internal-combustion engine driving alternators to secure electric power. However, with Paris convention on climate change, there is a growing interest in eco-friendly energy independent island that replaces microgrid(MG) consisting of photovoltaic, wind power, and energy storage system with alternators for internal combustion engines. And also, national emission trading has been implemented, and the price of certified emission reduction(CER) has a influence on system marginal price(SMP). Because, the low cost generation source decides SMP when CER price is low, while the more expensive generation source decides SMP when CER price is high. Therefore, the increasing of CER price has a strong influence on the annualized return of MG independent power producer. Moreover, the fixed RPS price is implemented from 2017, which the increasing of CER price under the fixed RPS price or the variable RPS price affects annualized return differently. In this paper, the annualized return according to CER price is analyzed for large, middle, and small scaled islands, the effect of CER price on the annualized return was confirmed.

• 전기학회논문지
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• 제68권1호
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• pp.199-206
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• 2019

Recently, an expansion of safety facilities has been widely applied to effectively manage the safety of train operation due to increase of the high-speed section of the general railway and the introduction of high-speed train. Accordingly, performance improvement, upgrading and high reliability of existing safety devices are required. the dragging detector, one of the safety devices, is an analogue system that consists of closed circuit with an electric current flows and operates when the closed circuit is opened by the impact of the dragging object. Such method has unreasonable problem that should be replaced after being detected. It is need to replace with an automatic return type dragging detector which is easy to maintain. In addition, it is necessary to develop a dragging detector that applicable to general railway and urban railway including high-speed railway, in accordance with the speeding up and densification of trains, although it is currently applied only to high-speed railway. In this paper, we propose an automatic return type dragging detector which has versatility and excellent maintainability with digital sensor and real time monitoring.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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• pp.641-643
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• 2000

CATV Network Management system of Korea is used for mainly monitor forward broadcasting signal because of the difficulty of tracking, measuring and control reverse path nosie. Thereby Purpose of this Structure is removing return Path noise of CATV Network for maintaining two way Netowrk Service of the Highest quality.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.99.5-99
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• 2001

This study presents a simulation of the traction return current based on $2{\times}25kV$ power supply system in order to determine the impedance bond intensity of impulse type track circuit on the electrified Gyeongbu line. The results of the simulation enables us to measure the precise intensity of catenary current that returns to the substation through KTX (Korean Train Express) operated by $2{\times}25kV$ power supply system with common earth network. The combination of $2{\times}25kV$ and common earth network established on the electrified Gyeongbu line for the first time in Korea. We show that the relationships among the traction return current, earth current, and catenary current, and catenary current can be applied to this line in order to determine the optimal impedance bond intensity ...

• 한국자동차공학회논문집
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• 제22권2호
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• pp.148-155
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• 2014

Most truck fires breaking out on the expressway are directly damaged by fire destruction of truck and freight and many of them cause indirect damage such as serious traffic holdups. This study analyzed the fire causes and their liability of the 25-ton truck fire breaking out during expressway driving. This truck fire was caused by manufacturing defect of return spring of a braking system. The fire liability rested with a maker(manufacturer) rather than a truck owner or a driver and the maker also bore fire liability based on the Product Liability Law.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.123-126
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• 2001

This study presents the simulation of the traction return current based on 2${\times}$25kV power supply system in order to determine the impedance bond intensity of impulse type track circuit on the Kyoungbo electrification line. The results of simulation enables us to measure the precise intensity of catenary current, returning to the substation through KTX (Korean Train Express) operated by 2${\times}$25kV power supply system with common earth network. In the wake of establishing 2${\times}$25kV and common earth network used in Korea for the first time, in particular, it is possible to determine the impedance bond intensity of impulse type track circuit, which is applicable to the Kyoungbo electrification line by specifying the relations among the traction return current, earth current, and catenary current.

• 한국정보통신학회논문지
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• 제14권9호
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• pp.2099-2104
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• 2010

본 연구에서는 마취 중 리턴맵 분석 방법을 적용하여 ECG 신호에서 R-R 간격의 변화로 표시될 수 있는 HRV 신호를 분석하였다. HRV신호는 자율신경계(autonomic nervous system : ANS)의 상태변이에 따른 심혈관계(cardio vascular system : CVS)의 변화 양상에 대한 객관적인 정보를 구할 수 있으므로 수술중 자율신경계의 변화를 관찰하여 마취심도를 평가할 수 있다. 리턴맵 분석 방법은 일련의 시계열 HRV 신호를 위상공간으로 사상하기 위해 지연시간과 매립차원을 구한 후 2차원의 위상공간에 신호를 재구성하였다. 위상공간에 재구성된 신호 분포를 타원형으로 근사화 한 후 장축과 단축의 길이를 구하여 마취심도를 구별하는데 이용하였다. 마취 단계별 마취심도를 평가하기 위하여 마취 단계를 7단계로 구분하여 분석하였다. 외부자극이 아주 강한 마취유도단계에서 장축과 단축 모두 통계적으로 유의하게 큰값을 나타내었으며, 외부 자극이 가해지지 않은 수술중 단계에서는 장축과 단축의 길이 모두 작은 값을 나타내었다. 따라서 2차원의 위상공간에 매립된 수술중의 HRV 신호를 이용하여 자율신경계의 영향을 판단하여 마취심도를 구분 할 수 있었다.

• International Journal of Fluid Machinery and Systems
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• 제3권1호
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• pp.11-19
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• 2010

The performance of the crossover system of a centrifugal compressor stage consisting of static components of $180^{\circ}$ U-bend, return channel vanes and exit ducting with a $90^{\circ}$ bend is investigated. This study is confined to the assessment of performance of the crossover system by varying the shape of the return channel vanes. For this purpose two different types of Return Channel Vanes (RCV1 and RCV2) were experimentally investigated. The performance of the crossover system is discussed in terms of total pressure loss coefficient, static pressure recovery coefficient and vane surface pressure distribution. The experimentation was carried out on a test setup in which static swirl vanes were used to simulate the flow at the exit of an actual centrifugal compressor impeller with a design flow coefficient of 0.053. The swirl vanes are connected to a mechanism with which the flow angle at the inlet of U-bend could be altered. The measurements were taken at five different operating conditions varying from 70% to 120% of design flow rate. On an overall assessment RCV1 is found to give better performance in comparison to RCV2 for different U-bend inlet flow angles. The performance of RCV2 was verified using numerical studies with the help of a CFD Code. Three dimensional sector models were used for simulating the flow through the crossover system. The turbulence was predicted with standard k-$\varepsilon$, 2-equation model. The iso-Mach contour plots on different planes and development of secondary flows were visualized through this study.