• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.3425-3434
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• 2024

The main features of the loading pattern optimization (LPO) problem, such as high-dimensionality, multi-modality, and non-linearity, make it difficult to achieve a truly optimal configuration. In recent years, metaheuristic methods have been successfully used to solve this problem. In this research, a discrete golden eagle optimization (DGEO) algorithm has been developed to solve the LPO problem in the first cycle of VVER-1000 reactor core. To evaluate the proposed algorithm, a linear multi-purpose fitness function has been used to improve the safety parameters of the reactor core by obtaining a flatter power distribution during the first cycle, and also to enhance the economic parameters by increasing the cycle length and reducing the cost of fuel recycling. For this purpose, a FORTRAN program has been written to map the DGEO algorithm for the LPO problem using the PMAX and PARCS core calculation code to compute the fitness function in each iteration. To speed up the calculations, parallel computing has been applied in the written program. The results demonstrated that the loading pattern, which is suggested by the DGEO algorithm, enhances all the safety and economic parameters in the fitness function. Thus, the DGEO algorithm is highly reliable for the LPO problems in the VVER 1000 reactor core.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.323-323
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• 1992

• Journal of the Korean Regional Science Association
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• v.8 no.1
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• pp.87-98
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• 1992

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.15-26
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• 2014

This paper proposes a Modified Particle Swarm Optimization with Time Varying Acceleration Coefficients (MPSO-TVAC) for solving economic load dispatch (ELD) problem. Due to prohibited operating zones (POZ) and ramp rate limits of the practical generators, the ELD problems become nonlinear and nonconvex optimization problem. Furthermore, the ELD problem may be more complicated if transmission losses are considered. Particle swarm optimization (PSO) is one of the famous heuristic methods for solving nonconvex problems. However, this method may suffer to trap at local minima especially for multimodal problem. To improve the solution quality and robustness of PSO algorithm, a new best neighbour particle called 'rbest' is proposed. The rbest provides extra information for each particle that is randomly selected from other best particles in order to diversify the movement of particle and avoid premature convergence. The effectiveness of MPSO-TVAC algorithm is tested on different power systems with POZ, ramp-rate limits and transmission loss constraints. To validate the performances of the proposed algorithm, comparative studies have been carried out in terms of convergence characteristic, solution quality, computation time and robustness. Simulation results found that the proposed MPSO-TVAC algorithm has good solution quality and more robust than other methods reported in previous work.

• International Commerce and Information Review
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• v.9 no.4
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• pp.107-125
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• 2007

With the rapidly increasing of Korean enterprises, the importance of foreign exchange(FX) risk management for the future operation generated from FDI contract is becoming the critical problem of international business. This type of FX risk, called as "economic exposure risk", requires us of the unique risk management principles and techniques. In this paper, we identify the properties of economic exchange rate exposure, analyze the identification and measurement processes of risk sources and strength, and perform the estimation of the main determinants and its profile effects of the invoicing currency for the efficient management of economic FX exposure.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.12
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• pp.603-610
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• 2002

In this paper, a new economic dispatch algorithm for unit commitment is proposed to improve both the accuracy of the final solution and the calculation speed of economic dispatch. By using the inverse incremental cost functions, economic dispatch can be transformed into a simple optimization problem associated with an n-th order polynomial equation. The proposed method remarkably reduces the computation time with adaptability to any higher order generation cost functions. The proposed method is tested with sample system, which shows that the proposed algorithm yields more accurate and economical generation scheduling results with high computation speed.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1506-1509
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• 1999

This paper presents a new economic dispatch algorithm to improve the unit commitment solution while guaranteeing the near optimal solution without reducing calculation speed. The conventional economic dispatch algorithms have the problem that it is not applicable to the unit commitment formulation due to the frequent on/off state changes of units during the unit commitment calculation. Therefore, piecewise linear iterative method have generally been used for economic dispatch algorithm for unit commitment. In that method, the approximation of the generator cost function makes it hard to obtain the optimal economic dispatch solution. In this case, the solution can be improved by introducing a inverse of the incremental cost function. The proposed method is tested with sample system. The results are compared with the conventional piecewise linear iterative method. It is shown that the proposed algorithm yields more accurate and economical solution without calculation speed reduction.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.3
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• pp.313-320
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• 2014

We consider the problem to find economic inventory quantity of a single commodity under stochastic demands and order cancellation. In contrast to the traditional economic production quantity (EPQ) model, we assume that once the amount of inventory reaches to a predetermined level of quantity then the production is not halted but its production speed decreases until the inventory level drops to zero. We establish two probabilistic models representing the behaviors of both the high-production period and low-production period, respectively, and derive the relationship between the level of inventory and costs of production, cancellation, and holding, from which the quantity of economic inventory is obtained.

• Journal of the Korean Home Economics Association
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• v.12 no.2
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• pp.581-600
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• 1974

The purpose of this study is clarify consumer problem on the basis of understanding consumer behavior, that is, to make explicit the effect of economic levels and educational background upon consumer consciousness and consumption behavior. The data in this study is from a survey in 1973 by means of a questionnaire of the opinions of 200 housewives of Seoul. The ${\chi}^2$(Chi-Squire) was applied for the statistical analysis of the data and following results were found. Generally consumers lack understanding of economic matters and satisfactory consciousness on matters of consumption life. And there is significant difference among the class on several matters. That is, the lower economic level and educational background are, the lower the understanding of economic matters and consciousness of satisfaction are. So the consumer education must be carried out for lower class of economic level and educational background. And in the present awakening of salers and makers is needed for consumers.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.297-303
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• 2022

The main purpose of the study is to determine the main aspects of the problem of socio-economic development in the conditions of the digital economy. The post-industrial era is characterized by the development of the electronic environment and the transition to an information civilization. In this regard, the developed countries of the world pay considerable attention to the development of the digital economy. However, there are a significant number of problems associated with this process. The country cannot be successful in the development of the digital economy in the absence of the necessary legal framework, an economic development strategy based on digital technologies. The research methodology involves the use of several theoretical methods for analyzing and synthesizing information. As a result of the study, the key problems of socio-economic development in the digital economy were characterized.