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전력산업 구조개편 환경에서 비선형 내점법의 최적조류계산에 의한 전력조류 및 한계계수에 관한 연구
정민화,남궁재용,권세혁 한국에너지학회 2002 에너지공학 Vol.11 No.4
본 연구에서는 전력산업 구조개편 환경에서 최적조류계산에 의한 전력조류 및 한계계수를 해석할 수 있는 실용적인 방법론을 제시한다. 먼저, 유용한 한계계수의 산정을 위해 전압제약, 선로과부하 제약, 발전 출력 제약 등의 각종 계통제약이 고려된 연료비 및 송전손실 최소화의 비선형 최적화 문제가 정식화되고 비선형 주·쌍대 내점법에 의한 해법이 제시된다. 또한, 최적조류계산에 의해 계산된 감도에 기초하여 한계가격 및 한계송전손실의 산정방법이 제시된다. 특히, 경쟁적 전력시장에서 송전손실에 관한 가격을 반영하기 위해 한계손실계수의 해석법이 제안된다. 본 연구의 결과를 IEEE RTS 24모선에 적용하여 전력시장가격의 해석에 대한 그 유용성을 검증하였다. This paper presents a practical methodology that can analysis power flow and marginal factors based on optimal power flow (OPF) of power systems under restructuring environment. First of all, to evaluate useful marginal factors, nonlinear optimization problems of minimum fuel cost and minimum transmission loss are formulated and solved by nonlinear primal-dual interior point method. Here, physical constraints considered in the optimization problems are the limits of bus voltage. line overloading, and real & reactive power generation. Also, an evaluation method of marginal price and marginal transmission loss is presented based on sensitivities calculated by the two OPF problems. Especially, to reflect the cost related to transmission losses in the competitive electricity market, an analysis method of MLF (marginal loss factor) is pro-posed. Numerical results on IEEE RTS 24 show that the proposed algorithm is effective and useful for analysis of power market price.
한국어 연속음성인식 시스템 구현을 위한 형태소 단위의 발음 변화 모델링
정민화,이경님,Chung Minhwa,Lee Kyong-Nim 대한음성학회 2004 말소리 Vol.49 No.-
In this paper, we describe a cross-morpheme pronunciation variation model which is especially useful for constructing morpheme-based pronunciation lexicon to improve the performance of a Korean LVCSR. There are a lot of pronunciation variations occurring at morpheme boundaries in continuous speech. Since phonemic context together with morphological category and morpheme boundary information affect Korean pronunciation variations, we have distinguished phonological rules that can be applied to phonemes in within-morpheme and cross-morpheme. The results of 33K-morpheme Korean CSR experiments show that an absolute reduction of 1.45% in WER from the baseline performance of 18.42% WER was achieved by modeling proposed pronunciation variations with a possible multiple context-dependent pronunciation lexicon.
정민화 圓光大學校 1992 論文集 Vol.26 No.1
Following rapid changes in firm's environments, new methods have been tried in cost accounting. The new establishment of architectures in cost accounting is requied because of changes in production technology including factory automation, and of the surge in strategic cost management, and of necessity to control cost accrual factors in overhead. New trends in cost accounting are as follows: First-Transformation into total cost management concept Cost should be controlled through product life life cycle from initial costs to post production costs. Initial costs include R & D costs, test production cost, and post production costs include cost for after sale service, polution control cost, etc. Second-Emphasis on Cost Planning Traditionally it has been regarded that cost plus margin constituted sales price. But under cost planning environments, cost is decided by sales price, given a competitive market, minus target income. That is, cost planning places more emphasis on cost reduction through process innovation and new product development than on cost control. Third-Prompt feedback of cost information to production site Cost information should be promptly reported to production site and feedbacks should be received immediately. Fourth-Cost management by Activity-Based on Costing(ABC) Cost should be managed by cost drivers, that is, by activities, in order to control overhead cost. ABC enables accurate measurement of income, reveals cost structure and enables optimal product mixture.