• 에너지공학
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• 제11권4호
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• pp.291-298
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• 2002

본 연구에서는 전력산업 구조개편 환경에서 최적조류계산에 의한 전력조류 및 한계계수를 해석할 수 있는 실용적인 방법론을 제시한다. 먼저, 유용한 한계계수의 산정을 위해 전압제약, 선로과부하 제약, 발전 출력 제약 등의 각종 계통제약이 고려된 연료비 및 송전손실 최소화의 비선형 최적화 문제가 정식화되고 비선형 주·쌍대 내점법에 의한 해법이 제시된다. 또한, 최적조류계산에 의해 계산된 감도에 기초하여 한계가격 및 한계송전손실의 산정방법이 제시된다. 특히, 경쟁적 전력시장에서 송전손실에 관한 가격을 반영하기 위해 한계손실계수의 해석법이 제안된다. 본 연구의 결과를 IEEE RTS 24모선에 적용하여 전력시장가격의 해석에 대한 그 유용성을 검증하였다.

• 한국사회복지학
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• 제63권1호
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• pp.113-135
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• 2011

현대에 들어 노동시장이 더 유연화 되고 있기 때문에 고용의 형태가 다양해지고 있고, 이에 따라 비정규직 일자리가 두드러지게 증가하고 있다. 비정규직 근로자는 고용 불안정과 열악한 근무 여건 때문에, 사회적 배제를 겪을 가능성이 크다. 그리고 비정규직 근로자가 사회적 배제를 겪을 경우에는 정신건강 문제를 경험할 가능성이 커진다. 이중에서 우울은 음주, 자살, 장애 등을 유발하는 증상이므로 관심을 가져야 할 정신건강 문제이다. 그러나 우리나라에서 비정규직 근로자의 사회적 배제와 정신건강 문제를 다룬 연구는 없다. 이에 따라 본 연구에서는 대표적인 비정규직 근로자인 건설직 일용근로자를 대상으로 사회적 배제와 우울 사이의 관계를 실증적으로 살펴보았다. 조사 결과, 일용근로자의 사회적 배제는 우울에 유의미하게 영향을 미치는 요인으로 나타났다.

• 대한치과보철학회지
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• 제45권6호
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• pp.760-768
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• 2007

Statement of problem. Conventional denture treatment for totally edentulous patients is associated with a variety of functional and psychosocial problems. The placement of implants in the anterior region of the maxilla and mandible and the fabrication of an implant-retained overdenture might solve these problems. Purpose. This study compared the marginal bone loss around the implant and evaluated the implant survival rate and complications in patients treated with overdentures retained by implants for 2 years. Material and methods. Patients who had received implant-retained overdentures using a Dolder bar at Samsung Medical Center from January 1999 to June 2005 and had participated in the annual recall programs for two years were selected for this study. A total of 18 patients and 56 $Br{\aa}ne-mark\;system^{(R)}$ implants were used, and their data were reviewed. Evaluations of the survival rate, bone quality, marginal bone loss, and complications were performed. The data on the Dolder bar length and clip length were measured. The change in marginal bone loss and the correlation between the marginal bone loss and bar length, clip length, or bone quality were investigated. Results. Implants placed in this study showed a 100% survival rate. The average annual bone loss was 1.12mm in the first year and 0.27mm in the second year in the maxilla, and 0.58mm in the first year and 0.22mm in the second year in the mandible. The marginal bone loss in the maxilla showed no significant association with those in the mandible. (P>.05). There was no significant difference in marginal bone loss around implants between the first and second year. (P>.05) There was no statistically significant relationship (P>.05) between the marginal bone loss and bone quality, clip length, or Dolder bar length. The Dolder bar length showed a high correlation with the clip length. (P<.05) Various complications were noted. Conclusion. These results confirmed the favorable outcome for patients treated with implant-retained overdentures.

• 한국시스템다이내믹스연구
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• 제17권1호
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• pp.107-134
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• 2016

Accelerated ageing with low fertility is one of the most critical problems in Korea. Because of ageing via low fertility, Korea will face a serious demographic cliff. This research primarily focus on the analyzing the dynamics of the marginal ageing state and decreasing population especially in Eup and Myeon region. This study based on the system dynamics approaches for finding causal loop structure of marginal ageing and critical mass of population disappearing. The results of this study are summarized as follows. First, demographic marginalization trends have already begun in the Eups and Myons of Gun. Second, marginal aging speed in Eup/Myeon areas is causing an population disappearing in the near future. Third, critical mass of population disappearing will begin when the rate of marginal aging is exceed 82% after 2023.

• 농촌계획
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• 제12권4호
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• pp.33-42
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• 2006

Recently, Korean government has been initiating various schemes for reactivation of the marginal farmland use. However, although about ten years have passed from the introduction of the marginal farmland redevelopment projects in 1995, there have been very few research works on their systematic and objective appraisal. Therefore, this study checked the statutory concept and development schemes of the marginal farmland, firstly. Ant through case studies on 5 completed project sites and questionnaire/interview surveys on local government officers/private developers, problems and suggestions on project implementation were analysed. Finally, in consideration with analysed results and suggestions together, tentative project directions and reaction schemes on marginal farmland development were proposed.

• 농촌계획
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• 제24권1호
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• pp.21-31
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• 2018

This study is a basic research for the development of 'Marginal Village Policy' in response to the hollowing-out of rural areas. For this purpose, the viewpoint of "Regeneration" & "Reconstruction" of the "Marginal Village Theory" and the recent "Rural Planning Theory of Evacuation" in Japan were reviewed. The background and trends of Marginal Village policy in Japan were also investigated. And based on this, the implications and future tasks for Korea were summarized as follows; (1)It is necessary to be interested in the disappearance of villages and marginal villages and to form positive discussions and social consensus. (2)Continuous field investigation and management of changes in population and village functions at regional and village level are required. (3)In addition to increasing the importance of depopulation problems, it is necessary to establish 'marginal villages' as a public policy target. (4)It is necessary to review and consider the viewpoint of reconstruction along with regeneration. (5)It is necessary to pay attention that the software project is expanded, and the regeneration & reconstruction policies of the rural villages are aimed at revitalizing the rural community. (6)It is necessary to consider the possibility of applying 'spacial construction' along with the expansion of the academic debate on the 'rural planning theory of evacuation'. On the basis of this, in this study, rural villages were classified into 'continuous villages', 'semi-marginal villages' and 'marginal villages' according to the degree of marginalization, and the basic framework of 'Marginal Village Policy' was proposed, which is to encourage the differentiated policies of 'continuous villages' by 'rural village policy', 'semi-marginal villages' and 'marginal villages' by 'marginal village policy'.

• 대한전기학회논문지
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• 제41권1호
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• pp.9-17
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• 1992

Proper resource allocation is also a very important topic in power system problems, especially in operation and planning. One such is optimal maintenance problem in operation and planning. Least cost and highest reliability should be the subjects to be pursued. A probabilistic operation simulation model developed recently by authors is applied to the proboem of optimal maintenance scheduling. Three different methods are compared, marginal maintenance cost, levelized risk and maintenance space. The method by the marginal maintenance costs shows the least cost, the highest reliability and the highest maintenance outage rates. This latter characteristics may considerably influence the results of genetation planning, because the usual maintenance outages obtained from the other methods have shown to be lower.

• 자원ㆍ환경경제연구
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• 제30권1호
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• pp.107-128
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• 2021

우리나라 전력시장에서 한계비용 기반의 가격결정메커니즘에 관한 논의가 이루어질 때 마다 한계발전기의 수익 감소는 가장 큰 장애물로 인식되었다. 하지만 수익감소는 한계비용 기반의 가격결정메커니즘의 한계점이 아니라 시장개설 초기 CBP체제의 단기 운영 계획, 발전계획프로그램의 기능 부재, 성능시험의 구조적 결함이 결합된 문제이다. 다조합 복합발전기에 운전조합별 비용함수를 적용할 경우 고출력구간에서 한계비용이 평균비용을 초과할 수 있으며, 이것은 비용함수를 산정하는 방식에 따라 가격결정메커니즘 제도개선을 가로막았던 구조적인 장애물을 극복할 수 있는 기회를 제공할 수 있다. 실시간 시장, 계통운영보조서비스 시장 등 재생에너지 확대를 수용하기 위한 전력시장 개선 및 DR, ESS 등 새로운 자원들의 시장참여 확대 등 향후 전력시장의 복잡성은 더욱 증가할 것으로 전망된다. 전력시장이 복잡해질수록 합리적인 가격신호를 제공하는 것이 바로 전력시장의 가장 중요한 역할이며 한계비용 기반의 가격결정메커니즘이 바로 전력시장 선진화의 출발점이 될 것이다.

• 한국주거학회논문집
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• 제25권3호
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• pp.35-43
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• 2014

Korea is the most rapidly aging country in the OECD countries, becoming 'an aging society' in 2010, when over 12% of the population had reached the age 65 and beyond. Along with the population aging, problems of the elderly have become a social issue. Also, the elderly population in most farming villages is increasing due to the cityward concentration of younger generation and the rapid urbanization centered around the capital area. Yet no definite success in revitalization of these villages has been reported despite the acknowledgement of the problems arising from such phenomena. Therefore, by examining "marginal villages" (communities whose joint social activities are difficult to maintain as over 50% of the population is 65 years or older) in Japan, which at this point has entered "the ultra-aged society" before Korea, this study intends to compare and analyze the countermeasure plans for the population decrease in these villages. The case study has been done with the focus on the literary references published in Japan such as papers, various reports, statistics, newspapers, and journals.

• 한국경영과학회지
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• 제24권2호
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• pp.109-119
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• 1999

The average shadow price is a substitute for the traditional marginal shadow price. It can serve as a standard for decision making problems about the economic resources where the marginal analysis gives no useful information. This paper treats the average shadow price in pure integer programming and shows some stability properties of it. This implies that the values of the average shadow prices once computed are reliable within some extent of the data perturbations of the integer programming model.