• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.194-196
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• 1989

The production costing plays a key role in power system expansion and operations planning especially for the calculation of expected energy, loss of load probability and unserved energy. Therefore, it is crucial to develope a probabilistic production costing algorithm which gives sufficiently precise results within a reasonable computational time. In this respect, a number of methods of solving production simulation have been proposed. In previous paper we proposed the method used Fast Hartley Transform in convolution process with considering only the thermal units. In this paper, the method considering the scheduling of pumped-storage plants and hydro plants with energy constraints is proposed.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1334-1336
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• 1999

전력산업의 구조개편으로 기존의 한국전력 독점체제에서 다수의 전력회사로 나누어 질 것이다. 따라서 손실과 공급의 신뢰도 확보 등의 책임분배와 비용분배의 문제가 새로이 나타날 것으로 예상된다. 손실에 대한 비용의 경우 계산법과 이러한 비용을 분배하는 방법이 중요한 문제가 되고 있다. 본 논문은 전력산업구조개편이 이미 이루어진 선진국들의 손실비용의 처리방법을 비교하였다. 그리고 손실에 대한 비용계산 방법을 모의 시스템에 각각 적용시켜보고 결과를 비교하였다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.61-69
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• 1995

a numerical method to the problem of mutual admittance between two slots is considered by use of conservation of complex power. Calculation of mutual admittance is compared with other results. And mutual admittance obtained by the method is used in the analysis for the broadband rectangular microstrip antenna geometry using E0plane gap coupling. The theoretical results for both return loss and radiation pattern of the broadband antenna are compared with experimental results. Good agreement between calculated and measured values has been observed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.9
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• pp.98-105
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• 1995

Recent microwave IC's reach to the extent of high operating frequencies at which bonding wires limit their performance as dominant parasitic components. Double bonding wires separated by an internal angle have been firstly characterized using the Method of Moments with the incorporation of the ohmic resistance calculated by the phenomenological loss equivalence method. For a 30$^{\circ}$ internal angle, the calculated total reactance is 45% less than that of a single bonding wire due to the negative mutual coupling effect. The radiation effect has been observed decreasing the mutual inductance, whereas for parallel bonding wires it greatly increases the mutual inductance. This calculation results can be widely used for designing and packaging of high frequency and high density MMIC's and OEIC's.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.5
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• pp.393-399
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• 2011

An empirical formula proposed by Petersson and Plunt(PP's formula) and finite element analysis for impedance calculation of ship equipment foundations are investigated by comparing the analysis results with those of experimental results. The PP's formula well estimates resonant frequency of the foundations and impedance level except around the resonant region although the impedance level around the resonant frequency is heavily dependent upon the assumed loss factor. The results show that the PP's formula and finite element models can be complementarily used to estimate the impedance characteristics of various types of foundation of ships in design stage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.306-312
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• 1992

The prevention of roll breakage in hot rolling process is improtant to reduce maintenance cost and production loss. Rolling conditions such as the roll force and torque have been intensively studied to overcome the roll breakage. in the present work, a model for life prediction of work rolls under working condition was developed and discussed. The model consists of stress analysis, crack propagation, wear and fatigue calculation model. Roll life can be predicted by stress, crack depth and fatigue damage calculated from this model. The reliability of stress analysis is backed up by the FEM analysis. From the result of simulation using by pressent model, although the fatigue damage of back up roll reachs 80% of practical limit, that of workroll was less than 40%. In edge section of workroll stress amplification is found by wear and bender effect. We can judge that workroll failures are not due to fatigue damage, crack propagation by bending stress but stress amplification by wear and bender in present working condition.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.101-106
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• 2008

Zonal cavity method, which is a kind of the lumen method, is used the calculation of the average illuminance on the workplane in an interior. Important factors of the method are cavity ratio, coefficient of utilization, and light loss factor. A Coefficient of Utilization varies with a kind of luminaires and is affected by surface reflectance of space. For this, the data from Coefficient of Utilization computation were analyzed with the same lumens and different photometry. This paper analyzes the changes of Coefficients of Utilization on the photometry of luminaires and surface reflectance of space.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.413-414
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• 2008

Abstract should be in English. The leaning angle optimization of turbine blade using the genetic algorithm was conducted in this paper. The calculation CFD technique was based upon the Diagonalized Alternating Directional Implicit scheme(DADI) with algebraic turbulencemodeling. The leaning angle of VKI turbine blade was represented using B-spline curve. The control points are the design variable. Genetic algorithm was taken into account as an optimization tool. The objective was to minimize the total pressure loss. The optimized final geometry shows the better aerodynamic performance compared with the initial turbine blade.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.405-411
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• 1999

Dynamic effect of gas in exhaust manifold influences the volumetric efficiency of the engine. Especially in case of multi-cylinder engine the shape of exhaust manifold is important for the opti-mum design of exhasut manifold complicated. In this paper the effects of exhaust manifold systems on volumetric efficiency were investigated for the 4 cylinder 4 stroke-cycle diesel engine. Volumetric efficiency was calculated by the method of characteristics. The calculation results coincided well the test results. This study showed that the appropriate position and diameter of exhaust manifold branch are important factors in increasing volumetric efficiency and decreasing pumping loss.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.780-784
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• 2003

This parer propose a new method to calculate nodal price which is very useful data in electric market under non-optimal operation. To calculate nodal price, we employ marginal cost and power flow, and consider network loss, generator capability, and line capability. The proposed method is applied to the test system and the usefulness is verified.