• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.301-309
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• 2009

A simple and efficient Lambda logic (${\lambda}-logic$) based algorithm is proposed for the solution of the generator constrained economic dispatch problem when the generating units having prohibited zones. The proposed method solves the economic dispatch (ED) problem that takes into account ramprate limits, transmission losses and prohibited operating zones in the power system operation. The proposed method uses a simple heuristic rule based on average power of prohibited operating zones which produces the feasibility of solution for the restricted operating units. The effectiveness of the algorithm is tested on five different test systems and the performance compared with other relevant methods reported in the literature. In all the cases, the proposed algorithm performs better than the previous existing algorithms with a less computational burden.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.172-174
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• 1996

This paper presents a new approach on genetic algorithms to economic dispatch problem for valve point discontinuities. Although it has been already shown that genetic algorithm was more powerful to economic dispatch problem for valve point discontinuities than other optimization algorithms, proposed approach in this paper on genetic algorithms improves the performance to solve economic dispatch problem for valve point discontinuities through combination in penalty function with death penalty, generation-apart elitism and heuristic crossover. Numerical results on an actural utility system consisted of 13 thermal units show that the proposed approach is faster and robuster than the classical genetic algorithm.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.744-751
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• 2013

In this paper, Secant method is proposed to solve multi area economic dispatch (MAED) problem. Generator limits of all generators in each area are calculated at given area power demands plus export (or import) using secant method and the generator limits of all generators are modified as modified generator limits. Central economic dispatch (CED) problem is used to determine the output powers of all generators. Here, Secant method is applied to solve the CED problem. The proposed approach has been tested on two-area (two generators in each area) system and four-area (four generators in each area) system. It is observed from various cases that the proposed approach provides optimally best solution in terms of cost with tie line loss with less computational burden.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.1
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• pp.10-15
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• 2012

This paper considers an economic design problem of a tree-based network which is a kind of computer network. This problem can be modeling to be an objective function to minimize installation costs, on the constraints of spanning tree and maximum traffic capacity of sub tree. This problem is known to be NP-hard. To efficiently solve the problem, a tabu list coupled genetic algorithm 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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.12
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• pp.1498-1506
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• 1999

In this paper, a hybridization of Evolutionary Strategy (ES) and a Two-Phase Neural Network(TPNN) is applied to the optimal environmental and economic operation. As the evolutionary computation, ES is to search for the global optimum based on natural selection and genetics but it shows a defect of reducing the convergence rate in the latter part of search, and often does not search the exact solution. Also, neural network theory as a local search technique can be used to search a more exact solution. But it also has the defect that a solution frequently sticks to the local region. So, new algorithm is presented as hybrid methods by combining merits of two methods. The hybrid algorithm has been tested on Emission Constrained Economic Dispatch (ECED) problem and Weighted Emission Economic Dispatch (WEED) problem for optimal environmental and economic operation. The result indicated that the hybrid approach can outperform the other computational efficiency and accuracy.

• East Asian Economic Review
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• v.19 no.1
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• pp.99-114
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• 2015

What explains the sharp increase in the Chinese economy's indebtedness, in particular the China's onshore corporate debt? Has the overall debt burden reached a threshold where it poses a systemic risk, thereby making the economy vulnerable to a "Lehman Moment" - with disorderly unwinding of the private sector and sovereign debt? What are the short and longer term implications of China's growing debt problems on domestic economic growth and the broader global political economy? What has Beijing done to ameliorate the problem, how effective were its efforts, and what must it do to deal with this problem?

• Korean Management Science Review
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• v.13 no.3
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• pp.37-48
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• 1996

This paper presents an Economic Lot Scheduling Problem in which controllable production rates are considered. We also take into account the controllable range of production rate (i.e., maximum and minimum production rate) of each product and the mold cost which varies to the production rate. A mathematical model is developed and an iterative solution procedure is suggested. The objective of this problem is to minimize production related cost and the decision variables are common production cycle time and production rate of each product. As a case study, we adapted this model to the press machine of a company.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.9
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• pp.424-430
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• 2001

A multi-level optimal power flow(OPF) algorithm has been evolved from a simple two stage optimal Power flow algorithm for constrained power economic dispatch control. In the proposed algorithm, we consider various constraints such as ower balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the two stage optimization method to an average gain of 2.99 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.

• Journal of Korean Home Economics Education Association
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• v.3 no.1
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• pp.131-146
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• 1991

The purpose of this study is to acquire basic materials to help the students Others of families in their homes through understanding them. This study was based on the questions asked to 100 students without parents in their homes and 100 students in standard homes. Percentage, T-test, counseling sample were used for statistical report. The following are the analysed results of this study. 1. Among the ten events, except for family life and economic problems, there were no distinguished contrasts between the students without parents in their homes and the students in standard homes. 2. The factors influencing stress are mainly plan for future, social environment, school life and learning and students without parents are especially affected by economic problem. 3. Comparing students without parents with one another in stress, the students without parents have economic problem and deficiency of affeetion, the students without father economic problem and their mothers health, the students without mother the difficulty of house affairs and emotional uneasiness of family. The students with step-mother have much misunderstasnding because of the lack of conversation among their family. The students with step-father hardly kconverse with their father and feel uneasy in family life. Based on all can be gailed these results, the following conclusion. 1) The students Other Types of families are stressed much more than the students in standard homes in family life and economic problems. 2) All Students are Stressed by bad environment, the plan of future, scholl and learning, 3) Comparing the Stubents without parents with one another, the students without parents have economics probem and deficiency of affeetion, the students without father economic problem and their mothers health, the students without mother house affairs and emotional uneasiness off family. The students of step-father and step-mother have the misuder standing by the lark of comversation, the deficiency of affection and the uneasiness off family life.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.1
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• pp.115-129
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• 2003

This paper Is concerned with a new techno-economic model Ing of ATM based h19h-speed networks. Coupled with advances of technology, the rapid development of new telecommunication services significantly increases the magnitude of risk in making an Investment decision. Naturally, the success of techno-economic modeling depends on how effectively we manage underlying risk factors such as cost and technology To deal with risk factors, we need to rely on modern decision and risk analysis while Implementing mathematical optimization for solving a complex capacity expansion problem of telecommunication systems during the planning period. We provide a case study that will enhance our understanding of the techno-economic analysis for emerging telecommunication systems.