• 대한전기학회논문지:전력기술부문A
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• 제53권5호
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• pp.285-295
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• 2004

The outage cost assessment has an important position for determination of the optimal level or optimal range of reliability for power system expansion planning. Establishing the worth of service reliability is a very difficult and subjective task. While the utility cost(reliability cost) will generally increase as consumers are provided with higher reliability, the consumer costs(reliability worth) associated with supply interruptions will decrease as the reliability increases. The total costs to society are the sum of these two individual costs and the optimum or target level of reliability is achieved at minimum point of the total cost curve. This paper addresses the role, need and assessment algorithms and methodologies of the outage cost in power system expansion planning. In a case study, the outage cost has been assessed using macro approach for our country 15years(1986-200l) in the case study. Additionally, determination processing of optimum reliability level is presented in another case study with the five buses MRBTS.

• 한국항해항만학회지
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• 제32권10호
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• pp.813-819
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• 2008

고유가와 자연환경에 대한 관심증대에 따른 선박의 환경규제로 많은 해운회사들이 어려움을 겪고 있으며 그에 따라 선박의 에너지 이용 효율성에 대한 관심이 증대하고 있다. 또한 향후 시간이 흐를수록 이러한 문제들의 중요성과 관심은 점점 증대될 것으로 보인다. 이에 대한 한 방안으로 독일의 Skyssails사가 4년간의 개발로 완성한 스카이세일즈 시스템은 새로운 관심을 가지게 한다. 이는 선박에 대형 연을 달아 연비를 낮추는 시스템으로 현재 유럽의 일부 선박에 실용화되고 있는 기술이다. 이에 따라 연의 활용과 관련이 깊은 국내연안의 날씨 등을 고려하여 동북아 피더네트워크가 발달되어 있는 국내연안에서 Strysail 활용에 대한 검토와 효용을 분석하고, 유류절감비용, 환경비용을 추정하였다. 그 결과 Strysail 시스템이 보조추진기구로써 연비절감과 환경비용절감에 많은 도움이 될 수 있음을 알 수 있었다.

• 전력전자학회논문지
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• 제19권5호
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• pp.391-398
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• 2014

This paper presents a resonant step-down DC/DC converter to reduce the voltage stresses of a 3-phase inverter module under the three-phase AC utility line condition. Under this condition, a conventional 3-phase inverter module suffers from high voltage stresses as a result of the high rectified DC link voltage; hence, a high-cost high-voltage-rating inverter module must be used. However, using the proposed converter, a low-cost low-voltage-rating inverter module may be adopted to drive the motor even under the 3-phase AC line condition. The proposed converter, which can be realized with small size inductor and low-voltage-rating semiconductor devices, operates at a high-efficiency mode because of the zero-current switching operations of all the semiconductor devices. The operational principles are explained and a design example is provided in the study. Experimental results demonstrate the validity of the proposed converter.

• 컴퓨터교육학회논문지
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• 제7권4호
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• pp.43-50
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• 2004

다국어 질의 응답 시스템은 여러 언어의 질의에 대한 응답을 하는 시스템이다. LASSO 시스템은 다국어 질의응답 시스템 중의 하나이다. 본 논문은 LASSO 시스템을 위한 한국어 해석 시스템의 설계 및 구현에 관한 것이다. 질의 응답을 위한 한국어 해석 시스템은 한국어 질의를 처리할 수 있는 대화체 처리 기술이 필요하다. 그리고 다양한 분야의 질의에 대한 응답을 할 수 있는 범용의 시스템이어야 한다. 본 논문의 한국어 해석 시스템은 이와 같은 사항을 만족하기 위하여 심도 깊은 대화체 처리 기술보다 실용성이 높은 휴리스틱 규칙을 활용하였다. 이 시스템은 다국어 질의 응답 시스템의 한국어 인터페이스 역할을 하는 것으로 질의 응답 시스템의 목적에 맞게 설계, 구현되었다. 본 해석 시스템에 적용된 기술은 정보검색 분야와 한국어 해석 분야에 응용할 수 있다.

• ETRI Journal
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• 제34권3호
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• pp.341-351
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• 2012

We deal with a resource allocation problem for multimedia service discrimination in wireless networks. We assume that a service provider allocates network resources to users who can choose and access one of the discriminated services. To express the rational service selection of users, the utility function of users is devised to reflect both service quality and cost. Regarding the utility function of a service provider, total profit and efficiency of resource usage have been considered. The proposed service discrimination framework is composed of two game models. An outer model is a repeated Stackelberg game between a service provider and a user group, while an inner model is a service selection game among users, which is solved by adopting the Kalai-Smorodinsky bargaining solution. Through simulation experiments, we compare the proposed framework with existing resource allocation methods according to user cost sensitivity. The proposed framework performed better than existing frameworks in terms of total profit and fairness.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.638-642
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• 2005

This paper presents incentive application strategies and delay prevention strategies as schematic approaches to improve time performance of highway construction contracts. This research recognizes the importance of improving time performance during highway construction. Strategic solutions of the most core issues on time performance incentive contracting are identified. The suggested incentive application strategies develop criteria for applying time classification to projects, for assigning project time classifications to contractors and designers, and for determining appropriate incentive values in A (cost) + B (time cost) and other performance incentive contracts. The suggested delay prevention strategies develop criteria for determining the appropriate subsurface utility engineering (SUE) level and to develop best practices for avoiding utility relocation delays. A schematic approach for each strategy is developed. This paper also introduces current incentive contracting practices in Florida. The researchers obtained the information from experienced persons in the highway construction industry, including key highway contractors, designers, and Department of Transportation (DOT) and Federal Highway Administration (FHWA) personnel. The major focus of this research is to develop strategies and suggest approaches to improve time performance of highway construction contracts. For future study, practical tools to facilitate implementation of the suggested strategies should be developed, so that the criteria, implementation processes, and best practices developed may contribute to the current industry-wide effort to improve time performance.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.367-374
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• 2013

Underground infrastructure systems provide essential public services and goods through buried structures including water and sewer, gas and petroleum, power and communication pipelines. The majority of existing underground infrastructure systems was installed in green field areas prior to development of complex urban built environments. Currently, there is a global trend to escalate major demand for underground infrastructure system renewal and new installation while minimizing disruption and maintaining functions of existing superstructures. Therefore, Engineers and utility owners are rigorously seeking technologies that minimize environmental, social, and economic impact during the renewal and installation process. Trenchless technologies have proven to be socially less disruptive, more environmentally friendly, energy conservative and economically viable alternative methods. All of those benefits are adequate to enhance overall sustainability. This paper describes effective sustainable solutions using trenchless technologies. Sustainability is assessed by a comparison between conventional open cut and trenchless technology methods. Sustainability analysis is based on a broad perspective combining the three main aspects of sustainability: economic; environmental; and social. Economic includes construction cost, benefit, and social cost analysis. Environmental includes emission estimation and environmental quality impact study. Social includes various social impacts on an urban area. This paper summarizes sustainable trenchless technology solutions and presents a sustainable construction method selection process in a proposed framework to be used in urban underground infrastructure capital improvement projects.

• 대한영양사협회학술지
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• 제10권3호
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• pp.293-299
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• 2004

The purposes of this study were to : a) investigate the current status of contracted hospital food services, b) analyze and clarify various perspectives of contractors and hospitals. Thirty six hospitals and their contractors which were having more than 100 beds located in Seoul, Inchon and Kyungkido, were the subjects of this study. Data were collected through surveys. The survey was conducted during March to April in 2002. Questionnaires were mailed to the 36 directors of dietetic departments of hospitals and 36 managers of contract foodservice management company. Statistical analysis was completed using SPSS Win(11.0) for descriptive analysis, t-test and $x^2$-test. The results of the study can be summarized ; 1. The type of contract considered adequate by directors of dietetic departments and managers of contractors was fee-contract, combined type, followed by profit-and-loss contract. 2. According to the results from analysis on the contract cost per meal considered adequate by directors of dietetic departments and managers, the directors of dietetic department indicated that showing no difference with the current contract cost per meal. However, the managers of contractor indicated that showing significant differences compared with the current contract cost per meal(regular diet p<0.01, therapeutic diet p<0.001). 3. In the composition of contract cost per meal considered adequate, the managers of contracting businesses accounted labor cost (p<0.01) as a major cost, whereas the chiefs of nutrition departments accounted miscellaneous or controllable expense (p<0.001) and VAT (p<0.01) as major costs. 4. The directors of dietetic departments and managers thought that the hospital should be responsible for utility costs. On the other hand, directors of dietetic departments regarded that the contractor and managers thought that the hospital should pay for facility investment cost.

• 경영과학
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• 제32권4호
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• pp.19-28
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• 2015

This study presents a mathematical programming model to develop production planning in the manufacturing processes for photovoltaic silicon ingots and wafers. The model is formulated as a linear programming model that maximizes total growth margin, which is composed of production cost, inventory cost, shortage cost, and sales profit while considering the constraints associated with the production environments of photovoltaic materials. In order to demonstrate the utility of the model for production planning, we run operations for a planning horizon of a year for a case study. When the primary results of this mathematical programming are compared with the historical records, the model could have resulted in the considerable increase of the total growth margin by effectively reducing inventory cost if a decision maker had employed the model as a decision support system with perfect information for sales demand.

• 한국군사과학기술학회지
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• 제12권5호
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• pp.557-562
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• 2009

Weapon system currently considers the research about effect analysis including cost effectiveness methodology for a budget management and an achievement of the military strategy goal. So that, this study considers the theoretical background, strength and weakness of several Multi-Criteria Decision Making, and an effect analysis of weapon system. And AHP(Analytic Hierarchy Process) is selected for the best effect analysis methodology of weapon system. Therefore, we applied AHP to the case study of the new generation Multiple Launcher Rocket System, performing the analysis of cost effectiveness methodology. Using AHP and cost effectiveness methodology, we propose the actual and proper decision making result.