• 조명전기설비학회논문지
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• 제22권4호
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• pp.130-138
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• 2008

뇌서지 전압이 전파되는 양상은 대상 전원계통과 기기별로 차이를 보인다. 하지만 뇌서지가 유입되는 대상기기를 중심으로 보면 뇌서지 침입경로는 전원선의 두 선간, 전원선과 대지간, 전원선과 PE도체, 중성선과 대지 간 등으로 구분되어진다. 또한 통신기기에서 전원측에서 들어오는 뇌서지 외에 통신선의 선간, 통신선과 대지 간으로 입사하는 경로가 존재한다. 이 논문은 각각의 경로를 통하여 대상기기에 침입하는 뇌서지에 대해 SPD를 사용한 전원계통의 안전향상 기법 중 독립접지, 공통접지, 바이패스 어레스터를 이용한 접지의 뇌서지 양상을 실증실험을 통하여 분석한 결과를 기술하고 있다.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.848-855
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• 2008

In this paper, we describe correspondence among multiple images taken by multiple cameras. The correspondence among multiple views is an interesting problem which often appears in the application like visual surveillance or gesture recognition system. We use the principal axis and the ground plane homography to estimate foot of human. The principal axis belongs to the subtracted silhouette-based region of human using subtraction of the predetermined multiple background models with current image which includes moving person. For the calculation of the ground plane homography, we use landmarks on the ground plane in 3D space. Thus the ground plane homography means the relation of two common points in different views. In the normal human being, the foot of human has an exactly same position in the 3D space and we represent it to the intersection in this paper. The intersection occurs when the principal axis in an image crosses to the transformed ground plane from other image. However the positions of the intersection are different depend on camera views. Therefore we construct the correspondence that means the relationship between the intersection in current image and the transformed intersection from other image by homography. Those correspondences should confirm within a short distance measuring in the top viewed plane. Thus, we track a person by these corresponding points on the ground plane. Experimental result shows the accuracy of the proposed algorithm has almost 90% of detecting person for tracking based on correspondence of intersections.

• Coupled systems mechanics
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• 제4권4호
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• pp.297-316
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• 2015

The use of fragility curves in the design of bridges is becoming common these days. In this study, experimental data have been used to develop fragility curves for the potential of girder unseating of a three-segment bridge and a bridge-abutment system including the influence of spatially varying ground motions, pounding, and abutment movement. The ground excitations were simulated based on the design spectra for different soil conditions. The Newmarket Viaduct replacement bridge in Auckland was used as the prototype bridge. These fragility curves were also applied to the 2010 Darfield and 2011 Christchurch earthquakes. The study showed that for bridges with similar characteristics as the chosen prototype and with similar fundamental frequencies, pounding could increase the probability of girder unseating by up to 35% and 30% based on the AASHTO and NZTA seating length requirements, respectively. The assumption of uniform ground excitations in many design practices, such as the NZTA requirements, could potentially be disastrous as girders might have a very good chance of unseating (as much as 53% higher chances when considering spatial variation of ground motions) even when they are designed not to. In the case of superstructures with dissimilar frequencies, the assumption of fixed abutments could significantly overestimate the girder unseating potential when pounding was ignored and underestimate the chances when pounding was considered. Bridges subjected to spatially varying ground excitations simulated based on the New Zealand design spectra for soft soil conditions with weak correlation shows the highest chances of girders falling off, of up to 65% greater than for shallow soil excitations.

• 전기학회논문지
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• 제66권5호
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• pp.877-884
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• 2017

A method of common earth, which is proposed by French Railway(SNCF) and is applied to high speed railway, minimizes the effect of the traction return current from tracks so that trackside electric devices can be protected and operation and maintenance staffs are kept out from injury in an electric railway environment. According to it, all the new domestic electric railway lines are replaced from existing individual earth method to the common earth method. In this paper, we analyze the correlation between common earth method and traction return current to prove whether the common earth has surely contributed to minimize the effect of the traction return current. The analysis was done based on the measurement of the traction return current at the domestic high speed railway line.

• 전력전자학회논문지
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• 제18권4호
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• pp.305-311
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• 2013

This paper proposes a performance improvement of existing single-phase current-fed qZ-Source inverter. Voltage gain of the traditional voltage-fed full-bridge inverter and single-phase current-fed qZ-source inverter is only equal to or smaller than input voltage. The proposed inverter can obtain twice higher voltage gain than the single-phase current-fed qZ-Source inverter by adding an extra switch and a capacitor in the circuit. In addition, the proposed inverter shares the common ground between dc input and ac output voltage. Therefore, the proposed inverter can eliminate the possible ground leakage current problem when it is used for grid-tied photovoltaic inverter system. A 120 W prototype inverter is built and tested to verify performances of the proposed inverter.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.285-288
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• 2007

This article presents the change characteristics of induced noise whether the sheath layer of the cable is grounded or not. As what affects the induced noise, there are power influence or longitudinal transverse voltages and its weighted filtered voltage. The sheath ground is basicaly predicted to have the effects of alleviation on the power influence. But practically the effects may not happen in the case of common cable's sheath layer. Rather there are cases that the ground of sheath affects so that the noise level could increase. So we need to scrutinize the effects of the sheath gorund in the measures for the protection against electromagnetic induction by powerline or traction line system. And the evaluation of using the designated shielding purpose cable is needed.

• 한국항행학회논문지
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• 제13권3호
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• pp.406-411
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• 2009

본 논문에서는 GSM(Global System for Mobile communication) 방식의 이동전화기에서 TDMA 잡음을 분석하기 위하여 잡음 대책 방법에 대하여 알아보고, 또한 잡음의 발생 원인에 대하여 기술한다. 또한 잡음 대책 방법 중 차이분석법을 이용하여 MIC를 shielding하고, 비드나 캐퍼시턴스를 장착하고, PCB의 Ground 보강으로 TDMA 잡음을 9dB, 3.5dB, 6dB 감소시켰다.

• Journal of Power Electronics
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• 제14권5호
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• pp.918-925
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• 2014

This study presents an extended boost single-phase qZ-source DC-AC inverter for a single-phase photovoltaic system. Unlike the previously proposed single-phase qZ-source and semi-qZ-source inverters that achieve the same output voltage as that of the traditional voltage-fed full-bridge inverter, the proposed inverter can obtain higher output than input voltage. The proposed inverter also shares a common ground between DC input voltage and AC output voltage. Thus, possible ground leakage current problem in non-isolated grid-tied inverters can be eliminated with the proposed inverter. A 120 W prototype inverter is built and tested to verify the performance of the proposed inverter.

• 기술사
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• 제44권5호
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• pp.42-47
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• 2011

Currently, wireless communication environment in high-rise buildings are limited in the basement and ground floor facilities are not in common use do not part, in case of disaster is difficult for efficient repression. In this paper, wireless communication facilities on the ground floor of the skyscraper by building infrastructure, wireless communications is proposed to eliminate shadows. That the presence of various wireless communication systems, wireless communication system proposed by this paper, TPS laying coaxial cable seals leak, and the propagation shades in place by installing indoor antenna is the solution to eliminate shadows. The wireless communications solutions reveal the advantages and features, a method of constructing the proposed design.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.172-180
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• 2011

When it essentially designs and develops the Railway Signal System H/W and S/W, It requires base to build an environment which the safety of the complete system can be certified objectively. It is not rational choice to progress the safety certification of each of the subsystems to ensure reliability from an economic point of view. Furthermore, Even though H/W and S/W already certificated the safety, In case of changing subsystem to comprise relevant system, The safety certification of its parts newly must proceed. This study to solve these problems covers safety H/W platform which is commonly applicable to composition plan at Ground railway signaling systems such as CBTC, ETCS, CBI and safety-based modeling approach with S/W development tools (SCADE) and certificated O/S (Pike) to build the development environment. In addition, When it designs and develops safety S/W, This study explains structure to separate the data section which for logical operations and logical operations itself and provides guideline to support the certification through minimizing changes to the software.