• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.978-981
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• 1998

This paper presents a newly developed transformer-less single phase inverter for a photovoltaic (PV) power system. In the proposed system, there is no earth-leakage current at all in the theoretical base, and the main circuit of this system is rather simple and it is expected the higher efficiency will be realized. The system is operated by a digital signal processor (DSP) which makes it more flexible in the control. From the experimental results, it is found that this new inverter supplies the AC power to utility grid line with the power factor of nearly unity.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.291-292
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• 2010

The main purpose of this study is to design and develop the grid connected 4kW photovoltatic PCS(Power Conditioning System) targeting for Japanese market. To make this task, the development of DC to DC converter, one phase inverter and EMI filters, and the research on connection between inverter and utility line are made. The developed 4kW PCS has fully carried out performance verifications and evaluation works and acquired the JET(Japan Electrical Safety & Environment Technology Laboratories) certification for safety and performance.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.148-150
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• 2002

The distributed jointing method is used in the underground tunnel due to narrow space of jointing. This method causes non-uniform length between cable joints. It has an effect on the sheath circulating current and the induced voltage. Furthermore the distributed jointing method may cause transient overvoltage resulting from lightning in underground cable which is connected with overhead line. The author diversely studied the sheath circulating current and induced voltage on underground cable depending on the distributed jointing length under the normal and the transient circumstances. The various simulation results really improve the cable system utility.

• Laser Solutions
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• v.8 no.1
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• pp.39-44
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• 2005

We report experimental results on the periodic patterning using a Ti:sapphire femtosecond laser (800nm, 100fs, 1kHz). Periodic structures with reproducible basic patterns are produced both on the surface and inside transparent materials. Period patterning for the application to display panel is widely investigated. Also, the submicron dot and line patterns are fabricated inside fused silica glass, which is important for the formation of diffraction grating in integrated optical circuit. finally, we demonstrate the utility of the femtosecond laser application to optical memory by fabricating the three-dimensional dot patterns.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.10
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• pp.418-425
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• 2006

This paper describes a simulation package for a power system using objected-oriented programming. The package includes four parts which are a power flow, a short circuit calculation, a transient simulation program, and an economic dispatch. The graphical user interface(GUI) is designed as a common platform which allows the user to create one-line diagrams of systems, specify components of power systems as well as simulation parameters, and view the output produced by the chosen application. The paper presents the data structure of the functional modules such as the draw module, power system data module, the power system simulation module, and the utility module using the object oriented programming. This package may be useful for educational and research purposes.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2764-2766
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• 2002

최근 국내 전력회사의 구조 조정이 구체화됨은 물론 세계적으로도 전력회사의 구조조정이 가속화 되어가고 있다. 기존의 독점체제에서 점차 경쟁 체제로 기업환경이 변화되고 있으며, 이에 따라 전력회사들은 기존의 단순한 전력공급이외에 다양한 부가서비스를 제공하기 위한 통신망을 구축하고자한다. 본 논문에서는 전력선 통신망을 이용하여 전력선 통신을 위한 전력부가 서비스를 제안하였다. 제안된 통신망은 수용가에 다양한 편리 서비스를 제공함과 동시에 수용가에 대한 AMR, 수요관리 등의 전력회사의 주요한 응용을 제공할 수 있도록 설계되었다.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2178-2180
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• 1998

Recently, for increasing consumed power and informational society, confidence of power supply is demanded. Beside, owing to most of these loads are nonlonear, utility line is polluted by these components, therefore, it is demanded compensation of harmonic current. In times past, special order of harmonic current is only compensated by passive filter, but active power filter can compensate whole harmonic current. Therefore, this paper propose uninterruptable power supply(UPS) with performance of active power filter.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1153-1154
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• 2006

This paper proposes the optimal design method based on NDZ analysis to secure the islanding defection ability and to maintain the stability and power quality when the grid is connected. A PSiM-based model and analysis of the system is presented, specialty aimed at improving the effectiveness of phase shift anti-islanding method with frequency feedback, which causes the inverter current to be generated slightly lower or higher in frequency than the frequency of the terminal voltage. The proposed method can cause frequency jump with leading and lagging phase of output current in two line cycles. As a result, the proposed algorithm is more sensitive and reliable than the conventional phase shift method. Experimental results, on a 3 kW inverter connected to 220 V, 60 Hz utility, are discussed.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.353-362
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• 2008

Operation data and fault data are recorded at the TCMS(Train Control and Monitoring System) of train are very important record for repairs and inspection of train. there are two ways to transfer the data today. one is using memory card and the other is using wireless communications. This paper is proposed about TCMS wireless depot analytical equipment that transfers data recorded in train to depot equipment via wireless method. The TCMS wireless depot equipment configuration is an AP(Access Point) and a central server PC at depot equipment. This method has the advantage of decrease of personnel expenses, collection time and convenience of staffs. This paper is verified about the utility of use, efficient establishment position of an AP at depot, the safety of data receiving, the exactitude of data and the shortening of transmission time. and this equipment is now operating at shin-jeong depot of SeoulMetro.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.7
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• pp.127-137
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• 1996

The 3-dimensional measurement using stereo vision system must achieve a camera calibration. So far, the 3-dimensional calibration technique that uses two-dimensional grid papar and a non-linear least square method has been developed and tested. But, this method is inefficient because it has many calculation procedure and a non-linear analysis. Therefore, this paper proposed the projective geometric method which produced the calibration parameter by vanishing point. The vanishing point is producted by a cross ratio and a parallel line pairs. The results of the computer simulation show utility of the proposed method.