• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1099-1109
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• 2018

For practical consideration, economic dispatch (ED) problems in power system have non-smooth cost functions with equality and inequality constraints that makes the problems complex constrained nonlinear optimization problems. This paper proposes a new constraint handling method for equality and inequality constraints which is employed to solve ED problems, where the incremental rate is employed to enhance the modification process. In order to prove the applicability of the proposed method, the study cases are tested based on the classical particle swarm optimization (PSO) and differential evolution (DE) algorithm. The proposed method is evaluated for ED problems using six different test systems: 6-, 15-, 20-, 38-, 110- and 140-generators system. Simulation results show that it can always find the satisfactory solutions while satisfying the constraints.

• 대한전기학회논문지:전력기술부문A
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• 제53권8호
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• pp.484-489
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• 2004

When the energy resource available to a particular plant (be it coal, oil, gas, water, or nuclear fuel) is a limiting factor in the operation of the plant, the entire economic dispatch calculation must be done differently. Each economic dispatch calculation must account for what happened before and what will happen in the future. This paper presents a formulation and a solution method for the optimization problem with a fuel constraint in a competitive electricity market. Take-or- Pay (TOP) contract for an energy resource is the typical constraint as a limiting factor. Two approaches are proposed in this paper for modeling the dispatch calculation in a market mechanism. The approaches differ in the subject who considers and inserts the fuel-constraint into its optimization problem. Market operator and each power producer having a TOP contract are assumed as such subjects. The two approaches are compared from the viewpoint of profits. surplus. and social welfare on the basis of Nash Equilibrium.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1508-1517
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• 2015

Optimal Power dispatch is the short-term decision of the optimal output of a number of power generation facilities, to meet the system demand, with the objective of Power dispatching at the lowest possible cost, subject to transmission lines power loss and operational constraints. The operational constraint includes power balance constraint, generator limit constraint, and emission dispatch constraint and valve point effects. In this paper, Opposition based Differential Evolution Algorithm (ODEA) has been proposed to handle the objective function and the operational constraints simultaneously. Furthermore, the valve point loading effects and transmission lines power loss are also considered for the efficient and effective Power dispatch. The ODEA has unique features such as self tuning of its control parameters, self acceleration and migration for searching. As a result, it requires very minimum executions compared with other searching strategies. The effectiveness of the algorithm has been validated through four standard test cases and compared with previous studies. The proposed method out performs the previous methods.

• KIEE International Transactions on Power Engineering
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• 제5A권3호
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• pp.221-227
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• 2005

This paper evaluates minimum and maximum power exchange considering economic and technical characteristics between Russia and ROK. First, we evaluate minimum power exchange to assure the economic feasibility by comparison with the total cost and benefit of the interconnected line. For evaluating maximum exchange power, system constraints are considered, which are examined through load flow and dynamic analysis by using the PSS/E program. As a result of these evaluations, we suggest the reasonable range of power exchange between ROK and Russia considering economic and technical constraints with the interconnection scenario that power system interconnection between ROK and Russia will be realized in the year 2010.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.341-343
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• 2000

Traditionally electric power system are operated in such a way that the total fuel cost is minimized regardless of accounting for tie-lines transmission constraint and emissions produced. But tie-lines transmission and emissions constraint are very important issues in the operation and planning of electric power system. This paper presents the Two-Phase Neural Network(TPNN) to solve the Economic Load Dispatch (ELD) problem with tie-lines transmission and emissions constraint considering transmission losses. The transmission losses are obtained from the B-coefficient which approximate the system losses as s quadratic function of the real power generation. By applying the proposed algorithm to the test system, the usefulness of this algorithm is verified.

• Asia Marketing Journal
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• 제18권4호
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• pp.125-138
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• 2017

The goal of the study is to understand how consumers' constraint as opposed to utility structure gives rise to final decision when consumers purchase more than one variant of product at a time, i.e., horizontal variety seeking or multiple-discreteness. Purchase and consumption decision not only produces utility but also involves some sort of cognitive pressure. Past consumption or last purchase is likely to be linked to this burden we face such as concern for obesity, risk of harm, and guilt for mischief. In this research, the existence and the role of dynamic constraint are investigated through a microeconomic utility model with multiple dynamic constraint. The model is applied to the salty snacks data collected from field study where burden for spiciness serves as a constraint. The results are compared to the conventional multiple discreteness choice models of static constraints, and policy implications on price discounts is explored. The major findings are that first, one would underestimate the level of consumer preference for product offerings when ignoring the carry-over of the concern from the past consumption, and second, the impact of price promotion on demand would be properly evaluated when the model allows for the role of constraint as both multiple and dynamic. The current study is different from the existing studies in two ways. First, it captures the effect of 'mental constraint' on demand in formal economic model. Second, unlike the state dependence well documented in the literature, the study proposes the notion of state dependence in different way, via constraint rather than utility.

• Environmental Engineering Research
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• 제21권4호
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• pp.409-419
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• 2016

As a major energy consumption province, the issue about the carbon emissions in Hebei Province, China has been concerned by the government. The carbon emissions can be effectively reduced due to a more rational energy consumption structure. Thus, in this paper the constraint of low carbon emissions is considered as a foundation and four energies--coal, petroleum, natural gas and electricity including wind power, nuclear power and hydro-power etc are selected as the main analysis objects of the adjustment of energy structure. This paper takes energy cost minimum and carbon trading cost minimum as the objective functions based on the economic growth, energy saving and emission reduction targets and constructs an optimization model of energy consumption structure. And empirical research about energy consumption structure optimization in 2015 and 2020 is carried out based on the energy consumption data in Hebei Province, China during the period 1995-2013, which indicates that the energy consumption in Hebei dominated by coal cannot be replaced in the next seven years, from 2014 to 2020, when the coal consumption proportion is still up to 85.93%. Finally, the corresponding policy suggestions are put forward, according to the results of the energy structure optimization in Hebei Province.

• 산업경영시스템학회지
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• 제31권1호
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• pp.101-107
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• 2008

This paper considers a topological optimization of a computer network design with a reliability constraint. The objective is to find the topological layout of links, at minimal cost, under the constraint that the network reliability is more than a given reliability. To efficiently solve the problem, a scatter search approach is proposed. Two illustrative examples are used to explain and test the proposed approach. Experimental results show evidence that the proposed approach performs more efficiently for finding a good solution or near optimal solution in comparison with a genetic algorithm approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1985년도 하계학술회의논문집
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• pp.131-133
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• 1985

• 한국노년학
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• 제40권1호
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• pp.197-216
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• 2020

본 연구는 노인들의 여가활동 제약요인들을 살피고, 특정 제약요인을 가진 노인들의 여가만족도를 높이기 위해서 실천적 측면에서 노인의 특성과 욕구에 기반 한 여가활동을 제안하고 정책적 지원 방안을 마련 할 목적으로 수행되었다. 노후보장패널 6차 부가조사자료를 활용하여 65세 이상 노인들 가운데 경제적 부담과 건강문제로 여가활동에 제약을 경험한다고 응답한 3167케이스를 분석하였다. 여가활동의 제약요인 집단별 여가만족도의 영향요인을 분석하기 위하여 인구사회적 특성(나이, 성별, 교육, 혼인상태, 독거여부, 지역, 적정생활비수준, 건강상태), 여가관련 변인(여가시간, 여가동기), 여가활동 변인(선호 활동, 비선호 활동)을 단계적으로 위계선형 회귀 모형에 입력하였다. 연구 결과는 다음과 같다. 첫째, 노인 여가활동의 주요한 제약원인으로는 경제적 부담과 건강 문제가 압도적으로 높았다. 둘째, 세 집단(재정취약집단, 건강취약집단, 재정+건강취약집단) 간의 여가관련 변인에서 차이가 나타났다. 여가활동 만족 수준은 재정취약집단이 가장 높게, 다음으로 건강취약집단, 재정+건강취약집단의 순서로 나타났다. 여가시간은 재정취약집단에서 가장 짧았으며, 여가동기에서는 재정취약집단에서 가족 및 주변 관계 때문이라는 응답은 높았으며, 건강유지라는 응답은 상대적으로 낮게 나타났다. 건강취약집단에서 휴식활동을, 재정취약집단에서는 오락취미 활동을, 그리고 재정+건강취약집단에서 사회활동을 선호 한다는 응답이 상대적으로 높게 나타났다. 셋째, 재정취약집단의 경우, 애완동물 돌보기 및 정원손질 같은 활동들을 선호 한다고 응답할수록 여가만족도가 높게 나타난 반면, 국내여행을 선호 한다고 대답할수록 여가만족도가 낮게 나타났다. 건강취약집단의 경우, TV 시청 및 라디오 듣기 등의 휴식활동을 선호 한다고 응답할수록 그리고, 비선호 한다고 응답할수록 모두의 경우에서 여가만족도가 낮게 나타났다. 이밖에도 종교활동 혹은 친목단체 활동과 같은 사회참여 활동을 선호 한다고 응답할수록 여가만족도가 높게 나타났다. 재정+건강취약집단의 경우, 집근처 산책 혹은 TV 시청, 국내여행 등의 활동을 여가활동으로 선호 한다고 응답한 노인일수록 여가만족도가 낮게 나타난 반면, 바둑, 장기, 체스 등의 오락 활동과 등산과 같은 취미활동, 그리고 친목단체 활동 등을 선호 한다고 응답한 노인일수록 여가만족도가 높게 나타났다. 본 연구는 노인 여가활동에 대한 전국단위의 데이터를 실증적으로 분석한 결과를 바탕으로 맞춤형 여가활동을 제안하고 정책적 지원 방안에 대한 논의를 포함하고 있다.