• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.54-62
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• 1999

This paper presents a study on the safety assessment of human body for electromagnetic field at unbalanced power system. The 3-phase load flow algorithm uses Newton-Raphson method based on Taylor series expansion of power flow equations in rectangular coordinates. The use of such a method can result in a solution with good convergence characteristics. In the safety assessment of human body, the approach based on fuzzy linguistic variable is employed to overcome the shortcomings resulting from a crisp set concept. The suggested scheme is applied to a 24bus system to validate the usefulness. The results for an unbalanced power system are compared with the results for a balanced power system.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1448-1450
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• 1994

The breakdown voltages of punchthrough-mode diodes with cylindrical junction are analytically calculated, The proposed method, which is based on th Gauss's law, estimates the lateral expansion of the depletion region as well as the electric field and the charge distribution. The proposed method is given in terms of epitaxial layer width, the epitaxial layer doping concentration, and curvature radius of the junction edge. The calculation results agree well with the MEDICI simulation results for various device parameters.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2203-2211
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• 2018

Capacity payment mechanism has been adopted as the incentive scheme to achieve resource adequacy in Korean electricity market, however, the level of capacity price has been controversial due to its insufficient extent to incur financial loss for certain generators. Therefore, a new method is proposed to estimate the proper level of capacity price incorporating profitability of market participants and resource adequacy in this paper. The proposed method is successfully applied to test system based on Korean power system.

• Journal of KIISE:Databases
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• v.27 no.2
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• pp.238-246
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• 2000

The distance join has been introduced previously, which finds nearest pairs in the order of distance incrementally among two spatial data sets built with multidimensional indexes like R-trees. We propose efficient K-distance joins when the number(K) of pairs to find is preset. Especially, we develop a distance join algorithm with bi-directional expansion and optimized plane sweeping using selection method of sweep axis and direction. The experiments on real spatial data sets show that the proposed algorithm is much better than the former algorithms.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.43-48
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• 2008

The characteristics of heat transfer of the bimetal disc for over-current protection device is specified. Bimetal consists of two metals which have a different thermal expansion coefficient. To analyze the thermal characteristics, temperature distribution when bimetal acts as a switch is calculated. As usual, heat source is applied to the bimetal and electric current is heat source in the over-current protection switch. In this paper, thermal distribution are obtained by solving a coupled electro-thermal field with 3D finite element method.

• Journal of Multimedia Information System
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• v.6 no.4
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• pp.283-292
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• 2019

This paper introduces the development and current prosperity of the branch discipline of visual anthropology and describes the status and current situation of modern visual anthropology and analyzes the rationality that the achievements of visual anthropology is viewed as texts and enjoy the same achievements, making it more basis and scientific in the selection of visual anthropology in subsequent research. This article comprehensively uses Delphi method and analytic hierarchy process to construct an evaluation system of visual anthropology, as well as put forward the basic principles of screening films using this evaluation system in subsequent studies and a simple outlook for future expansion.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.4
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• pp.341-348
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• 1990

This paper describes an algorithm for evaluating the Loss of Load Probability (LOLP) and calculating the production cost for all the generators in the system using Fast Hartley Transform (FHT). It also suggests the deconvolution procedure which is necessary for the generation expansion planning. The FHT is as fast as or faster than the Fast Fourier Transform (FFT) and serves for all the uses such as spectral, digital processing, and convolution to which the FFT is normally applied. The transformed function using FFT has complex numbers. However, the transformed function using FHT has real numbers and the convolution become quite simple. This method has been applied for the IEEE reliability test system and practical size model system. The test results show the effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.184-186
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• 2005

Increasement of power demand rapid industrial growth has led the expansion of power system, and it caused construction of large power transmission line(like 765kV T/L) and substation. If there are T/L faults (route contingency etc), it lead to the large scale black out in SEOUL AREA (the center of load). To minimize damage which caused by the large scale black out, KEPCO selects the method of load shadding. In this work, instead of general method of load shadding, We study the application of UVLS model to decrease the load shadding in SEOUL AREA. The study result of using the UVLS model showed that the amont of load shadding can be decreased about 400 MW compare to the existing load shadding system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.4
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• pp.304-314
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• 2002

Performance analysis of the automotive air-conditioning system is conducted by using computer simulation, and performance tests are carried out by using the climate wind tunnel in order to verify simulation. Evaporator and condenser were modeled by using empirical correlation which was obtained from calorimeter data, and compressor was modeled by using map based method. The steady state thermodynamic conditions of refrigerant satisfying mass and energy balance were assumed in the simulation program for automotive airconditioning system. The system performance was analyzed by finite difference method until differential air enthalpy between evaporator inlet and outlet becomes converged. Simulation results are in good agreement with experimental results at most operating conditions. Variation of discharge temperature and pressure of compressor, outlet temperature of evaporator, cooling capacity, and COP were investigated in term of air volume flow rate for evaporator, compressor capacity, compressor speed, superheat of thermostatic expansion valve, and diameter of suction line.

• Nuclear Engineering and Technology
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• v.9 no.3
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• pp.151-163
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• 1977

Being based on the Segal method, calculation was carried out for the natural uranium nuclear fuel cost with Zircaloy-4 cladding having design Parameters of Wolsung Nuclear Power Plant, CANDU-PHWR (Unit 1) , currently under construction in Korea aiming at its completion in 1982. An attempt was also made for tile sensitivity analysis of each fuel component; j. e., depreciation of fuel manufacturing plant caused by its life time, its load factor, production scale expansion of plant facilities, variations of construction and operating costs of fuel manufacturing plant, fluctuation of interest rates, extent of uranium ore price increases and effect of learning factor.