• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1542-1548
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• 2018

When any faults occurred in electrical railway system, operators need to analysis it quickly and accurately. Existing COMTRADE based analysis tools are not enough to analysis faults occurred in electrical railway system. In this paper, it presents some functions to fault analysis for electrical railway system based on fault data formatted COMTRADE. These functions are implemented in PSCAD/EMTDC and it can be shown that analyzed results against actual electrical fault cases which were occurred in the electrical railway power system.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.151-152
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• 2006

Multi-hop system has advantage of low power consumption, improved cell capacity, and enlarged service coverage. Most of previous researches show that multi-hop relaying beyond dual-hop relaying does not improve system performance significantly. This leads most researches are focused on dual-hop relaying system. In this paper, we propose an optimal boundary condition to support maximal data rate for fluctuation of traffic load in single cell dual-hop relay system.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.73-76
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• 2002

In electrical machinery and apparatus, the most important problem is protect of machinery and apparatus in due to transient phenomena and overload on operation. Particularly by advanced technology of late, there Is demand for low cost of equipments and high percentage of use of equipments. Therefore, protection of machinery and apparatus In condition of overload is more valued considering that all efficiency increase is passed by operating all machinery and apparatus in condition of heavyload. In this paper, the suggested system is added overload interrupt system using CT in condition of overload.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.986-989
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• 2000

The traditional method to construct Geographic Information System (GIS) is to scan the published maps, then the important and difficult step is to digitize the maps data. It costs a lot of time and human resource. Because a Global Positioning System (GPS) can offer high accurate digital signal directly, we developed a new method that uses the GPS to construct the GIS.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.1
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• pp.23-26
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• 2003

This paper proposes a new artificial immune approach to hardware test. A novel algorithm of generating tolerance conditions is suggested based on the principle of the antibody diversity. Tolerance conditions in artificial immune system correspond to the antibody in biological immune system. The suggested method is applied to the on-line monitoring of a typical FSM (a decade counter) and its effectiveness is demonstrated by the computer simulation.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.580-590
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• 2018

Active distribution system (ADS) considering distributed generation (DG) and electric vehicle (EV) is an effective way to cut carbon emission and improve system benefits. ADS is an evolving, complex and uncertain system, thus comprehensive model and effective optimization algorithms are needed. Battery swapping station (BSS) for EV service is an essential type of flexible load (FL). This paper establishes ADS planning model considering BSS firstly for the minimization of total cost including feeder investment, operation and maintenance, net loss and carbon tax. Meanwhile, immune binary firefly algorithm (IBFA) is proposed to optimize ADS planning. Firefly algorithm (FA) is a novel intelligent algorithm with simple structure and good convergence. By involving biological immune system into FA, IBFA adjusts antibody population scale to increase diversity and global search capability. To validate proposed algorithm, IBFA is compared with particle swarm optimization (PSO) algorithm on IEEE 39-bus system. The results prove that IBFA performs better than PSO in global search and convergence in ADS planning.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.410-413
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• 1998

In this paper, we present the method that improve alarm security system using the electronic circuits added the emergency lamp by our proposed Algorithms. In conventional method the emergency lamp of warning & alarm system didn't work perfectly its performance because of battery with short life. For improving this problem we, using Peripheral Interface Controller IC, designed the circuit added the emergency lamp for an warning & alarm system and for prevention against stopping the electric current, and compared our proposed method with conventional method. By designing the circuit to stop up over charge we can extend life of battery, use for a stoppage of electric current in emergency and according to the lightness around. Therefore we are very convenient and profitable in our life. In the future we will study the method to lower the cost of architecture for practical utilization.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.350-357
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• 2005

This paper presents a mechanical sensorless vector-controlled system with parameter identification by the aid of image processor. Based on the flux observer and the model reference adaptive system method, the proposed sensorless system includes rotor speed estimation and stator resistance identification using flux errors. Since the mathematical model of this system is constructed in a synchronously rotating reference frame, a linear model is easily derived for analyzing the system stability, including motor operating state and parameter variations. Because it is difficult to identify rotor resistance simultaneously while estimating rotor speed, a low-accuracy image processor is used to measure the mechanical axis position for calculating the rotor speed at a steady-state operation. The rotor resistance is identified by the error between the estimated speed using the estimated flux and the calculated speed using the image processor. Finally, the validity of this proposed system has been proven through experimentation.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.92-96
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• 2003

This paper deals with the characteristics of persistent current switch (rCS) system fer applied HTS magnet system. To apply the high-Tc superconductor in superconducting machine such as motror, generator, MAGLEV, MRI, and NMR, the study on high-Tc superconducting persistent current mode must be performed. In this experiment, the PCS system consists otd superconducting magnet, PCS and magnet power supply. The superconducting magnet was fabricated by connecting four double pancake coils (DPCs) in series. The PCS was inductive double pancake coil type and heated up by the SUS 303L tape heater. The optimal length of PCS was calculated and thermal quench state of PCS was simulated by using finite element method(FEM) and compared with experimental results. The optimal energy to normalize the PCS was calculated and introduced. Finally, the persistent current was observed with respect to various ramping up rate and magnitude of charging current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.368-371
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• 2003

The humidity sensors with a stable characteristics and gas sensors operating at room temperature have been fabricated, and a multi-functional sensor system which has gas sensor, humidity sensor, temperature sensor and control circuit has been applied to the microwave oven system. For a suitable cooking state, the humidity sensors was more applicable to heating and defrosting condition than gas sensors, however, the dynamic characteristics of gas sensors were obtained in the easy burning food such as pop corn.