• 한국GIS학회:학술대회논문집
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• 한국GIS학회 1999년도 추계학술대회 발표요약문
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• pp.21-25
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• 1999

Planning support systems(PSS) add more advanced spatial analysis functions than Geographic information systems(GIS) and intertemporal functions to the functions of spatial decision support systems(SDSS). This paper reports the continuing development of a PSS providing a framework that facilitates urban planners and civil engineers in conducting coherent deliberations about planning, design and operation & maintenance(O&M) of water-distribution networks for urban growth management. The PSS using dynamic optimization model, modeling-to-generate-alternatives, value engineering(VE) and life-cycle cost(LCC) can generate network alternatives in consideration of initial cost and O&H cost. Users can define alternatives by the direct manipulation of networks or by the manipulation of parameters in the models. The water-distribution network analysis model evaluates the performance of the user-defined alternatives. The PSS can be extended to include the functions of generating sewer network alternatives, combining water-distribution and sewer networks, eventually the function of planning, design and O&H of housing sites. Capacity expansion by the dynamic water-distribution network optimization model using MINLP includes three advantages over capacity expansion using optimal control theory(Kim and Hopkins 1996): 1) finds expansion alternatives including future capacity expansion times, sizes, locations, and pipe types of a water-distribution network provided, 2) has the capabilities to do the capacity expansion of each link spatially and intertemporally, and 3) requires less interaction between models. The modeling using MINLP is limited in addressing the relationship between cost, price, and demand, which the optimal control approach can consider. Strictly speaking, the construction and O&M costs of water-distribution networks influence the price charged for the served water, which in turn influence the. This limitation can be justified in rather small area because price per unit water in the area must be same as that of neighboring area, i.e., the price is determined administratively. Planners and engineers can put emphasis on capacity expansion without consideration of the relationship between cost, price, and demand.

• 인터넷정보학회논문지
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• 제5권5호
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• pp.17-26
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• 2004

모바일 멀티캐스팅은 크게 원격가입과 양방향 터널링 기법으로 나누어진다. 원격가입 방법은 멀티캐스트 트리를 관리하는데 많은 비용이 발생하며, 앙방향 터널링 방법은 비효율적인 라우팅 경로를 가지게 된다. 본 논문에서는 패킷의 터널링 및 트리 재구성 비용과 관계되는 비용함수에 근거하여 동작하는 동적 이동 멀티캐스트 라우팅 기법을 제안한다. 동적 이동 멀티캐스트 라우팅 기법은 기본적으로 비용함수를 사용하여 홈 에이전트로부터 멀티캐스트 패킷을 터널링하는 포워딩 비용과 왜래 에이전트가 멀티캐스트 그룹에 가입하는 멀티캐스트 트리 재구성 비용 사이의 적은 비용을 찾고자 하는 것이다. 이동 호스트가 외래 에이전트의 영역으로 이동한 경우, 외래 에이전트는 포워딩 비용과 트리 재구성 비용에 따른 비용함수를 구하여 비용함수에 의해 계산된 임계값을 중심으로 패킷의 포워딩을 계속할 것인가 아니면 새롭게 전달 트리를 재구성 할 것인가를 동적으로 결정하게 된다. 이 방법은 이동 호스트의 이동 속도나 그룹 구성원의 수에 관계없이 최적의 전송비용으로 멀티캐스트 패킷을 전달하는 효과를 가져올 수 있다.

• 전기학회논문지
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• 제56권5호
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• pp.848-853
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• 2007

This paper presents a methodology of estimating incomplete information in electricity markets for analyzing the gaming behavior of Generating Companies (GENCOs). Each GENCO needs to model its opponents' unknown information of strategic biddings and cost functions. In electricity markets with complete information, each GENCO knows its rivals' payoff functions and tries to maximize its own profit at Nash equilibriurnl Nli) by acknowledging the rivals' cost function. On the other hand, in the incomplete information markets, each GENCO lacks information about its rivals. Load patterns can change continuously due to many factors such as weather, price, contingency, etc. In this paper, we propose the method of the estimation of the opponents' cost function using market price, transaction quantities. and customer load patterns. A numerical example with two GENCOs is illustrated to show the basic idea and effectiveness of the proposed methodology.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권1호
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• pp.6-14
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• 2012

All types of part-of-speech (POS) tagging errors have been equally treated by existing taggers. However, the errors are not equally important, since some errors affect the performance of subsequent natural language processing seriously while others do not. This paper aims to minimize these serious errors while retaining the overall performance of POS tagging. Two gradient loss functions are proposed to reflect the different types of errors. They are designed to assign a larger cost for serious errors and a smaller cost for minor errors. Through a series of experiments, it is shown that the classifier trained with the proposed loss functions not only reduces serious errors but also achieves slightly higher accuracy than ordinary classifiers.

• 산업경영시스템학회지
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• 제5권6호
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• pp.69-78
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• 1982

Traditional CVP (Cost-Volume-Profit) analysis employs linear cost and revenue functions within some specified time period and range of operations. Therefore CVP analysis is assumption of constant labor productivity. The use of linear cost functions implicity assumes, among other things, that firm's labor force is either a homogenous group or a collection homogenous subgroups in a constant mix, and that total production changes in a linear fashion through appropriate increase or decrease of seemingly interchangeable labor unit. But productivity rates in many firms are known to change with additional manufacturing experience in employee skill. Learning curve is intended to subsume the effects of all these resources of productivity. This learning phenomenon is quantifiable in the form of a learning curve, or manufacturing progress function. The purpose d this study is to show how alternative assumptions regarding a firm's labor force may be utilize by integrating conventional CVP analysis with learning curve theory, Explicit consideration of the effect of learning should substantially enrich CVP analysis and improve its use as a tool for planning and control of industry.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.12-14
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• 1994

Traditionally one convex cost function for each generation is assumed in economic power dispatch. However, it is more realistic to represent the cost function as a piecewise quadratic function rather than one convex function. This paper presents evolutionary algorithm approaches to solve the problems of economic power dispatch with quadratic cost functions and piecewise quadratic cost functions. To improve GA, EP and ES characteristics. optimization methods combining GA with ES and EP with ES are proposed. The results for the proposed algorithms are compared with those of numerical method and show the better solutions in the ELD problem.

• 산업경영시스템학회지
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• 제19권40호
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• pp.233-240
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• 1996

A fixed amount compensator is proposed for a process with a linear tool wear function. A Cost model is constructed which involve process adjustment cost and quality loss. Symmetric and asymmetric quadratic functions of the deviation of a quality measurement from the nominal target value are considered as the quality loss functions. Methods of finding optimal values of initial setting and compensation limit are presented and a numerical example is given.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.143-146
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• 2004

This paper presents a method to improve reliability by dispersed generation (DG) installation considering load types and interruption cost. The objective functions such as power losses cost, operation cost of DGS, power buy cost and interruption cost are minimized for reliability improvement and efficient operation. The several indices for reliability evaluation are improved by dispersed generation system installation.

• 한국인터넷방송통신학회논문지
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• 제15권6호
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• pp.257-266
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• 2015

비 볼록 발전비용함수에 대한 최적화 문제는 다항시간으로 해를 구하는 알고리즘이 알려져 있지 않아 전기분야에서는 부득이 2차 함수만을 사용하고 있다. 본 논문은 비 볼록 발전비용함수의 경제급전 최적화 문제에 대한 밸브지점 최적화 알고리즘을 제안하였다. 제안된 알고리즘은 초기 치로 최대 발전량 $P_i{\leftarrow}P_i^{max}$로 설정하고, 평균 발전단가가 $_{max}\bar{c}_i$인 발전기 i의 발전량을 밸브지점 $P_{ik}$로 감소시키는 방법을 적용하였다. 제안된 알고리즘을 13과 40-발전기 데이터에 적용한 결과 기존의 휴리스틱 알고리즘보다 좋은 성능을 보였다. 따라서 비 볼록 발전비용함수의 경제급전문제 최적 해는 각 발전기의 밸브지점 발전량으로 수렴함을 보였다.

• 대한산업공학회지
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• 제11권1호
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• pp.3-10
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• 1985

Periodic replacement policies are proposed for a system whose repair cost, when it fails, can be estimated by inspection. The system is replaced when it reaches age T (Policy A), or when it fails for the first time after age T (Policy B). If it fails before reaching age T, the repair cost is estimated and minimal repair is then undertaken if the estimated cost is less than a predetermined limit L; otherwise, the system is replaced. The expected cost rate functions are obtained, their behaviors are examined, and ways of obtaining optimal T and L are explored.