• Transactions on Control, Automation and Systems Engineering
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• 제4권4호
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• pp.324-329
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• 2002

In this paper, the guaranteed cost filtering design method for linear time delay systems with convex bounded uncertainties in discrete-time case is presented. The uncertain parameters are assumed to be unknown but belonging to known convex compact set of polytotype less conservative than norm bounded parameter uncertainty. The main purpose is to design a stable filter which minimizes the guaranteed cost. The sufficient condition for the existence of filter, the guaranteed cost filter design method, and the upper bound of the guaranteed cost are proposed. Since the proposed sufficient conditions are LMI(linear matrix inequality) forms in terms of all finding variables, all solutions can be obtained simultaneously by means of powerful convex programming tools with global convergence assured. Finally, a numerical example is given to check the validity of the proposed method.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.201-207
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• 2007

As the power industry moves towards open competition, there has been a need for methodology to evaluate distribution power system reliability by using customer interruption costs, particularly in power supply zones under the competitive electricity market. This paper presents an algorithm to evaluate system average interruption duration index, expected energy not supplied, and system outage cost taking into consideration failure rate of the distribution facility and industrial customer interruption cost. Also, to apply this algorithm to evaluate system outage cost presented in this paper, the distribution arrangement of a dual supply system consisting of mostly high voltage customers in an industrial complex in Korea is used as a sample case study. Finally, evaluation results of system interruption cost, system average interruption duration index, and expected energy not supplied in the sample industrial complex area are shown in detail.

• 한국경영과학회지
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• 제17권1호
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• pp.117-117
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• 1992

Pubilc utility industries including the electric utility industry are facing a new stream of privatization com-petition with the private sector and deregulation. The necewssity to solve now and in the future power supply and demand problems has been increasing through the sophisticated generation expansion plan(GEP) approach con-sidering not only KEPCo's supply-side resources but also outside resources such as non-utility generation(NUG) demand-side management (DSM). Under the environmental situation in the current electric utility industry a new approach is needed to acquire multiple resources competitively. This study presents the development of a modified electric generation expansion analysis system(EGEAS) model with avoided cost based on the existing EGEAS model which is a dynamic program to develope an optimal generation expansion plan for the electric utility. We are trying to find optimal GEP in Korea's case using our modified model and observe the difference for the level of reliabilities such as the reserve margin(RM) loss of load probability(LOLP) and expected unserved energy percent(EUEP) between the existing EGEAS model and our model. In addition we are trying to calculate avoided cost for NUG resources which is a criterion to evaluate herem and test possibility of connection calculation of avoided cost with GEP implementation using our modified model. The results of our case study are as follows. First we were able to find that the generation expansion plan and reliability measures were largely influenced by capacity size and loading status of NUG resources, Second we were able to find that avoided cost which are criteria to evaluate NUG resources could be calculated by using our modified EGEAS model with avoided cost. We also note that avoided costs were calculated by our model in connection with generation expansion plans.

• 한국산림과학회지
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• 제106권4호
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• pp.473-479
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• 2017

본 연구는 유실수, 특용수, 산채 및 고로쇠 등을 주업으로 임업만 생산했을 경우와 자연순환농법으로 닭을 방사하여 키우는 산지양계와 결합한 복합경영일 경우의 조수입이 어느 정도 향상되었는지를 분석하였다. 연구대상지는 충청북도 충주시, 경상북도 경산시, 강원도 화천군에 위치하고 있는 3곳의 산지양계 복합경영 현장실연 임가이다. 그리고 현장 면담조사를 통해 2015년도 기준의 경영비와 조수입을 조사하여 산지양계의 비용구조와 경영성과를 비교 분석하였다. 연구결과, 충주는 조수입이 25,608,000원, 경영비가 20,217,571원으로 소득은 5,390,429원으로 분석되었고, 경산은 조수입이 33,950,000원, 경영비가 18,655,714원으로 소득은 15,494,286원인 것으로 나타났다. 화천은 조수입이 31,850,000원, 경영비가 13,143,000원으로 소득은 18,707,000원이었다. 그리고 판매량과 비용이 일치하는 손익분기 판매량은 충주는 617마리, 경산은 125마리, 화천은 63마리로 나타났다. 1마리당 가격에서 차지하는 원가율은 충주는 79%를 차지하였고, 경산은 55%, 화천은 41%를 차지하였고 이에 따른 마진율은 충주는 21%, 경산은 45%, 화천은 59%로 나타났다. 또한 산지양계복합경영의 소득효과는 조수입 기준으로 평가한 결과, 임업만 주업으로 할 때 보다 충주가 16%, 경산이 18% 그리고 화천이 11%로 증가한 것으로 나타났다.

• 전자공학회논문지D
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• 제34D권5호
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• pp.52-60
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• 1997

Photonic switching systems with throughput above Tbit/s are reuried to transport vast amounts of information for the coming B-ISDN. In this paper, we proposed a new time-division hybrid WDM photonic swithc architecture, the proposed basic switch module has simple configuratin consisted of frequency routers for wavelength division and cell coders and star couplers for time division. Through the comparison with other sysems in field of switching capacity, hardware complexity and cost effect of implemetnation, we proved that the proposed system is suitable for large-capacity photonic switching system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.160-160
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• 2000

An optimization approach is used to solve the division problem of working area, and a cost function is defined to represent the constraints on the solution, which is then mapped onto the Hopfield neural network for minimization. Each neuron in the network represents a possible combination among many components. Division is achieved by initializing each neuron that represents a possible combination and then allowing the network settle down into a stable state. The network uses the initialized inputs and the compatibility measures among components in order to divide working area.

• Journal of Construction Engineering and Project Management
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• 제5권3호
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• pp.1-9
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• 2015

Project cost is an important concern in any construction project. Although there has been a lot of studies on factors affecting the cost of construction projects, there seems no consensus as what cost factors have direct influence on the cost of civil engineering projects. This study therefore aims to bridge the current knowledge gap by examining quantity surveyors' perception of the factor structure among nineteen costing attributes identified based on literature review. Questionnaire was used to elicit responses from quantity surveyors working in the Hong Kong construction industry. Principal component analysis is conducted to extract the factor structure of the cost attributes and the attributes are grouped into three factor components, namely the contract management factor, the project management factor and the monetary value factor. Understanding these cost impact factors could be crucial in managing civil engineering projects, since it allows the project stakeholders and quantity surveyors to take precautionary steps to identify the cost management problems and areas for improvement and could even help to avoid cost deviations in engineering projects.

• 한국경영과학회지
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• 제39권3호
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• pp.51-61
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• 2014

In this paper, we deal with developing a cost estimation relationships (CER) for Korean maneuverable weapons systems using historical production cost. To develop the CER, we collected the historical data of the production cost of four tanks and five armored vehicles. We also analyzed the Required Operational Capability (ROC) of the weapons systems and chose cost drivers that can compare operational capabilities of the weapons systems We used Forward selection, Backward selection, Stepwise Regression and $R^2$ selection as the cost drivers which have the greatest influence with the dependent variables. And we used Principle Component Regression, Robust Regression and Weighted Regression to deal with multicollinearity and outlier among the data to develop a more appropriate CER. As a result, we were able to develop a production cost CER for Korean maneuverable weapons systems that have the lowest cost errors. Thus, this research is meaningful in terms of developing a CER based on Korean original cost data without foreign data and these methods will contribute to developing a Korean cost analysis program in the future.

• 한국환경복원기술학회지
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• 제15권6호
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• pp.29-41
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• 2012

This study was conducted in Ningxia Hui autonomous region, located at southern part of Mu Us sand land in China. To investigate relationships between windbreak effect and installation cost of sand barriers, plastic net is utilized by using four kind of heights (0.2, 0.3, 0.4 and 0.5m) and four kind of porosities (20, 30, 50 and 70%). These heights and porosities are measured for estimating distances for effective windbreak. It is shown that porosity and the distance have a positive relationship at same heights and porosity on ground indicates a constant figure when height reaches a certain level, regardless of the porosity. This implies that there is a difference of level of windbreak with different porosities; however, distance of windbreak effect is same at the same height of sand barrier. As a result of comparison between porosity of sand barrier on the ground and installation cost in each sand barrier with various heights and porosities (16 combinations), 0.4m and 0.5m height sand barriers describe highest economical efficiency. Within two variables, we concluded that height has a higher impact on windbreak effect than porosity.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 추계학술대회 논문집
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• pp.263-268
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• 2005

최근 선박의 대형화 추세에 따라 항만의 장비 및 시설 또한 대형화 추세에 있다. 특히 이러한 경향은 부산항, 상해항등 대형 Hub-Port의 역할을 수행하는 항만들의 항만 간 경쟁측면에서 두드러지게 나타나고 있다. 그러나 5,000TEU급 이상 대형 선박 수는 제한적이고, 입항선박의 $70\%$이상(부산항 기준)이 2만톤 이하인 중소형 선박으로서 이 선박들에 대한 하역시설에 대한 고려가 필요함에도 이를 지나치게 간과하는 측면이 있다. 장비 및 시설의 대형화는 높은 비용 투자로 인해 중소형 선박 작업 시 높은 하역원가가 적용되므로 중소형 선사는 하역비 부담, 운영사는 중소형 선박 기피와 같은 현상을 가져올 수 있다. 본 연구의 목적은 선박크기, 크레인 규모와 수, 인력구조 둥을 반영한 시간가치 비용을 산정함으로써 선박 규모별 투입 크레인과 인력구조의 적정성을 평가하는 데 있다.