• 농촌지도와개발
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• 제13권2호
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• pp.265-276
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• 2006

This study focused on the trends in recognising an economic concern as the most difficult problem in the farm household that was categorised as a full-time farm household or a part-time household according to income structure from agricultural activity. Log-linear models were suggested to compare the change of recognising an economic problem between year 2003 and 2005. As a result, there was no significant difference in recognising an economic problem between full-time farm household and part-time farm household both in 2003 ($x^2$＝0.04;p＝0.84) and in 2005 ($x^2$＝1.08; p＝0.30). It was revealed, however, that full-time farm household had increasingly recognised an economic problem over years. Log-linear models showed that full-time farm households tended to recognise the economic problem 1.11 times as much as part-time farm households in 2005, compared to 0.97 times in 2003.

• 가정과삶의질연구
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• 제9권1호통권17호
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• pp.241-257
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• 1991

The objectives of this study are : to measure the level of rent burden. to examine the independent influences of the variables related to rent burden. to measure the level of family economic problem perception. to examine the differences in the level of family economic problem perception due to rent burden, household characteristics, housing characteristics and rent incresing. For these purpose, a survey is conducted using questionaires. The data used in this study included 369 renters living in Seoul. Statistics uses for data analysis were Frequency Distribution. Percentile, men, Pearson's Correlation, Partial Correlation, One-way ANOVA, Breakdown and Multiple Regression Analysis. Major findings are as follows : The average score of rent burden was 35.87, Therefore rent burden of large cities, rental households is very heavy. Family income, housing facility quality, rent type, and rent incresing have independent influences on rent burden. The average of family economic problem perception is above the mid-point of the scale. The level of family economic problem perception differs due to rent burden, family income, family life cycle, family size, occupation of household head, education leval of household head and homemaker, rent type, housing type, housing size, housing facility quality and rent increases. If the level of rent burden is below 25, family economic problem perception is adequate.

• 가정과삶의질연구
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• 제24권1호
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• pp.141-158
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• 2006

The purpose of this study was to investigate the changes of lives and problems of 'Kirogi'(or Wild Goose) fathers, who were called fathers in the 'Kirogi' families, South Korean families separated by an ocean. They almost sent too much money that were $50-100\%$ of their family income to the families abroad, and got economic pressures so severely. More or less, they sold their own real estates, moved to much smaller sized house. and often expended the saving money. Also, they had difficulties of taking care of their children and felt lonely very much. By the hand, they might experience the adaptation process through 3 stages-troubles, acception(or wandering or enjoy), adjust (or violation). They had three types of problems, that is, family relationship problem(the isolation), psychological problem(loneliness and self-control), economic problem (financial pressure and drop of economic status). They found the strategies to overcome these problems for themselves. Firstly, they took lots of methods like email, internet chatting, phone, etc. to communicate with their family everyday and made many events to strengthen the ties among families. Secondly, they got rid of stresses mainly by joining with their colleagues at work. Finally, they decided to lower the standard of living of their family in foreign country or tried to find their wives' jobs to prevent the financial hardship.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1106-1108
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• 1997

This paper presents a new approach on genetic algorithms to economic dispatch problem for valve point discontinuities. 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, atavism and heuristic crossover. Numerical results on an actual utility system consisted of 13 thermal units show that the proposed approach is faster and robuster than classical genetic algorithm.

• 환경위생공학
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• 제8권2호
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• pp.49-64
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• 1993

The present waste problems require a change of thinking with regard to conventional economics. It has been generally believed that competitive markets maximize social welfare. But, the other hand, a few economists argue that "the competitive markets cannot always be relied on to provide all goods in the efficient amount." One of the best examples of the latter contention is the environmental problem. What is the basic thinking of the conventional economics that causes this problems \ulcorner What is the present problem that requires the change of conventional economic thinking \ulcorner The environmental problem result from the conventional economic thinking such as pursuing the limitless of the Gross National Product(GNP), believing the increasing returns in economics of scale and the efficiency of competitive market. This economic principles, howe- ver, does not apply currently to public goods, especially environmental amenity and natural resource because the price of markets does not reflect the natural goods of services. We call this eternality. Externalizes are no considered by either buyers or sellers of goods of which production or use results in an eternality. This leads to market failure are causes an waste problem in the economic activities. Today, it is almost impossible to say in a word what the solution for waste problems is because they are by-products complicated and entangled human activities. In this paper, I have introduced the causes of environmental problems only from the economic point of view. I have also described the needs of conversion of conventional economic thinking. Firstly, sustainable development, maintaining the natural resources, should be the basis of the economic growth rather that pursuing the limitless growth of GNP. Secondly, an appropriate scale of human's production activity should be taken into account to reduce the impact to the natural environment. Thirdly, internalization of eternality is asked to correct the market failure. This requires the public policy such as imposing a talsubsidy, assigning a property right or implement a more detailed environmental quality standard through, because use of the natural resources can be. allocated optimally by the intervention of government or social associations.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.19-27
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• 2009

This paper presents a newly developed optimization algorithm, the Bee Optimization Algorithm (BeeOA), to solve the economic power dispatch (EPD) problem. The authors have developed a derivative free and global optimization technique based on the working of the honey bee. The economic power dispatch problem is a nonlinear constrained optimization problem. Classical optimization techniques fail to provide a global solution and evolutionary algorithms provide only a good enough solution. The proposed approach has been examined and tested on two test systems with different objectives. A simple power dispatch problem is tested first on 6 generators and then the algorithm is demonstrated on 13 thermal unit systems whose incremental fuel cost function takes into account the value point loading effect. The results are promising and show the effectiveness and robustness of the proposed approach over recently reported methods.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.320-330
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• 2008

This paper presents an improved dynamic programming (IDP) approach to solve the economic power dispatch problem including transmission losses in power systems. A detailed mathematical derivation of recursive dynamic programming approach for the economic power dispatch problem with transmission losses is presented. The transmission losses are augmented with the objective function using price factor. The generalized expression for optimal scheduling of thermal generating units derived in this article can be implemented for the solution of the economic power dispatch problem of a large-scale system. Six-unit, fifteen-unit, and forty-unit sample systems with non-linear characteristics of the generator, such as ramp-rate limits and prohibited operating zones are considered to illustrate the effectiveness of the proposed method. The proposed method results have been compared with the results of genetic algorithm and particle swarm optimization methods reported in the literature. Test results show that the proposed IDP approach can obtain a higher quality solution with better performance.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.52-59
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• 2008

This paper describes the secant method for solving the economic dispatch (ED) problem with generator constraints and transmission losses. The ED problem is an important optimization problem in the economic operation of a power system. The proposed algorithm involves selection of minimum and maximum incremental costs (lambda values) and then the evaluation of optimal lambda at required power demand is done by secant method. The proposed algorithm has been tested on a power system having 6, 15, and 40 generating units. Studies have been made on the proposed method to solve the ED problem by taking 120 and 200 units with generator constraints. Simulation results of the proposed approach were compared in terms of solution quality, convergence characteristics, and computation efficiency with conventional methods such as lambda iterative method, heuristic methods such as genetic algorithm, and meta-heuristic methods like particle swarm optimization. It is observed from different case studies that the proposed method provides qualitative solutions with less computational time compared to various methods available in the literature.

• 산업경영시스템학회지
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• 제19권39호
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• pp.229-234
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• 1996

When we analyze equipment replacement problem, we take the table of the duration period of tangible fixed asset on the corporation income tax law, and treat depreciation as simple allocation process for capital recovery. In this problem, there are some papers considering the concepts of economic depreciation. Those are not perfect model from a economical point of view. Therefore, we deal with equipment replacement problem considering the engineering valuation as well as the economic concept in the evaluation of asset.

• 가정과삶의질연구
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• 제17권1호
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• pp.155-166
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• 1999

The purpose of this study was to analyze a causal relationship of children's behavior problem and the related variables(socio-economic status mother's psychological problem mother's affective parenting behavior children's negative emotionality and children's self-control). The major findings of this study were as follows: 1) Socio-economic status had indirect in influence to children's behavior problem via mother's psychological problem and mother's affective parenting behavior. 2) Mother's psychological problem had direct influence and also indirect influence to hildren's behavior problem via mother's affective parenting behavior and children's negative emotionality. 3) Mother's affective parenting behavior and children's negative emotionality had a direct effect on children's behavior problem and affected indirectly via children's self-control. 4) Children's self-control had direct influence to children's behavior problem. 5) Mother's psychological problem was the most signi icant variable affecting children's behavior problem.