• KIEE International Transactions on Power Engineering
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• 제12A권1호
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• pp.31-35
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• 2002

This paper presents a new operation scheme of UPFC to minimize both generation costs and active power losses in a normal operation state of power system. In a normal operation, cost minimization is a matter of primary concern among operating objectives. This paper considers two kinds of costs, generation costs and transmission losses. The total generation cost of active powers can be minimized by optimal power flow, and active power losses in the transmission system can be also minimized by power flow control of UPFC incorporated with minimization of generation costs. In order to determine amounts of active power reference of each UPFC required for the cost minimization, an iterative optimization algorithm based on the power flow calculation using the decoupled UPFC model is proposed. For verification of the proposed method, intensive studies have been performed on a 3-unit 6-bus system equipped with a UPFC.

• 한국IT서비스학회지
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• 제14권3호
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• pp.67-84
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• 2015

Software is more diverse and complex and the level of importance for the maintenance of application software to securely operate software is also gradually increasing in proportion. The calculation method for maintenance cost of application software applied in Korea public enterprises is involved in the range of 10 to 15% of development cost, depending on the Software Project Cost Estimation Guide. Moreover, as most software maintenance cost estimation procedures do not take into consideration of the risk factors related of maintenance, it can be seen as a main cause for the occurrence of maintenance related accidents. This study proposes a maintenance cost estimate model that takes into consideration of the risks related to the software maintenance activities to improve and resolve issues arising from the estimation of maintenance cost. In doing so, maintenance risk factors are analyzed and a risk index is derived through the analysis of risk levels based on the risk factors. Based on such analysis, a maintenance cost estimate method which reflects the maintenance risk index was established.

• 경영과학
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• 제17권1호
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• pp.117-134
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• 2000

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.

• 정보화정책
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• 제22권1호
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• pp.47-72
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• 2015

전세계적으로 국가정보화가 진전됨에 따라 다양한 분야에서 개인정보의 침해위협이 급증하고 있어, 이에 대응하기 위한 정부차원에서의 정보보호대책이 마련되어지고 있다. 특히, 우리나라에서는 개인정보처리시스템의 안전성을 높이기 위한 방안으로, 2011년 개인정보 보호법에 근거한 개인정보 영향평가제도가 도입되었다. 그러나 개인정보 영향평가를 위한 대가기준의 변동요소들이 반영되지 못하고, 안전행정부(2011)에서 제시한 기본 예산보다 낮게 책정되면서 영향평가과정의 품질관리 및 영향평가서의 질적 수준도 저하되었다. 따라서 본 연구에서는 개인정보 영향평가가 개인정보보호를 위한 사전예방적 제도로 정착될 수 있게 필요한 예산 산정과 적용이 이루어지는 기준을 제시해보고자 한다. 이를 위해 기존 문헌, 유사제도의 대가기준, 개인정보 영향평가서 등을 검토하였으며, 전문가대상의 델파이분석을 통한 개선된 기준을 도출하였다. 이에 따라 개인정보 영향평가의 대가 산정 모델은 개인정보 영향평가고시에 따른 인력구성에 따라 기본인건비로 삼고, 대상시스템의 구분, 대상시스템의 구축 운용비, 대상시스템의 유형 등에 따라 가중치하는 방식을 채택하였다. 이처럼 개인정보 영향평가를 위한 대가 산정의 모델은 공공기관에서 개인정보보호를 위한 예산집행의 투명성과 영향평가사업의 신뢰성을 확보하는데 기여하리라 본다.

• 토지주택연구
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• 제14권1호
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• pp.135-144
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• 2023

현재 LH공사에서 활용하고 있는 건설폐기물 처리대가 기준은 오래전에 개발된 표준 모델을 활용하여 대가를 산정하고 있다. 따라서 본 모델은 폐기물 처리시설의 기술발전과 환경상황을 잘 반영하지 못하는 문제점을 갖고 있다. 따라서 본 연구에서는 이러한 문제점을 개선하기 위해 건설폐기물 중간처리 대가기준에 대한 분석을 실시하였다. 공공발주기관과 LH에서 활용하고 있는 원가계산방식의 현황과 차이점을 분석하였다. 또한 폐기물 중간처리업체의 운영실태에 대한 현장조사 및 전문가 인터뷰 등을 실시하여 현재 활용되고 있는 표준모델에 대한 개선모델을 제시하였다. 건설폐기물의 중간처리를 위한 주요 공정은 건설폐기물의 파쇄기 투입, 파쇄, 선별 및 분별, 이송으로 이루어져 있다. 본 모델에 맞추어 공정운영에 필요한 소요인력과 비용을 분석하여 발주를 위한 적산 기준을 제안하였다. 이 개선된 표준모델은 공공기관의 폐기물 중간처리를 위한 원가계산 기준으로 활용될 수 있으며, 폐기물처리비의 증액이 필요한 것으로 판단하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.550-553
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• 2005

To acquire radar target signature, various kinds of target are necessary. Measurement is one of the data acquiring method, but much time and high cost is required to get the target data from the real targets. Even if we can afford that, the targets we can access are very limited. To obtain target signatures avoiding these problems, we build the target CAD (Computer Aided Design) model for the calculation of target signatures. To speed up RCS calculation, we applied adaptive super-sampling and tested quite complex tank CAD model which is 1.4 hundred of thousands facet. We use calculated RCS data for ID range profile and 2D ISAR (Inverse Synthetic Aperture Radar) image formation. We adopted IFFT (Inverse Fast Fourier Transform) algorithm combined with polar formatting algorithm for the ISAR imaging. We could confirm the possibility of the construction of database from the images of CAD models for target classification applications.

• 전기의세계
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• 제29권1호
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• pp.53-57
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• 1980

The analytical treatment for a terminal cost problem of a distributed reactor with a small singular parameter is presented. The inverse of the neutron velocity is regarded as a singular parameter, and the model, adopted for simplicity, is a cylindrically symmetrical reactor. The Helmholtz mode expension is used for the application of the optimal theory for lumped parameter systems to the spatially distributed parameter system. The closed-form solution is explicitely obtained for machine calculation.

• 대한토목학회논문집
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• 제30권6D호
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• pp.655-662
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• 2010

사회기반시설은 국가 경쟁력 지표로써, 전통적으로 정부의 SOC 재정으로 건설되어 왔다. 그러나 SOC 예산 축소에도 불구하고 사회기반시설의 확충 요구를 해결하기 위해 민간투자사업제도가 도입되었으며, 이 중 도로사업의 비중이 높다. 본 연구는 기 제안된 도로사업 사업계획서의 운영관리비와 사업계획서와 연계되는 재무모델의 운영관리비 항목을 분석하고, 도로사업의 특성을 반영하기 위해 한국도로공사의 사업비 항목과 운영관리 업무를 분석하였다. 분석 결과를 통해 분류체계를 마련하여 비용산정 기준을 마련하는 것이 요구된다. 또한 업무의 효율성을 고려하여 기존의 업무 도구를 웹기반으로 통합하여 하나의 시스템으로 개발하는 것을 제안하였다. 이를 통해 민간투자사업의 전체적인 사업성 확보에 기여하고, 수익성을 기반으로 하는 사회기반시설의 확충에 기여할 것으로 기대된다.

• 한국전자통신학회논문지
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• 제18권5호
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• pp.867-876
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• 2023

본 연구에서는 감마족 분포(Erlang, Log-Logistic, Rayleigh)을 적용한 NHPP 소프트웨어 개발 비용 모형의 속성을 새롭게 분석하였고, 모형의 속성을 검증하기 위해 Goel-Okumoto 기본 모형과 비교한 후, 이를 근거로 최적의 모형도 제시하였다. 소프트웨어 신뢰도를 분석하기 위하여 시스템 운영 중 랜덤하게 발생한 고장 시간 데이터를 활용하였고, 모수의 계산은 최우추정법을 사용하여 해결하였다. 다양한 속성 분석(평균값 함수, 개발 비용, 최적의 방출시간)을 통하여 종합적으로 평가한 결과, Rayleigh 모형이 가장 우수한 성능을 가진 모형임을 확인하였다. 본 연구를 통하여, 기존 연구 사례가 없는 감마족 분포를 적용한 소프트웨어 개발비용 모형의 속성을 새롭게 규명하였다. 또한, 개발자들이 초기 단계에서 본 연구 데이터를 효율적으로 활용할 수 있도록 기초적인 설계 데이터도 제시할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.620-626
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• 2004

For general nonlinear processes, it is difficult to control with a linear model-based control method and nonlinear controls are considered. Among the numerous approaches suggested, the most rigorous approach is to use dynamic optimization. Many general engineering problems like control, scheduling, planning etc. are expressed by functional optimization problem and most of them can be changed into dynamic programming (DP) problems. However the DP problems are used in just few cases because as the size of the problem grows, the dynamic programming approach is suffered from the burden of calculation which is called as 'curse of dimensionality'. In order to avoid this problem, the Neuro-Dynamic Programming (NDP) approach is proposed by Bertsekas and Tsitsiklis (1996). To get the solution of seriously nonlinear process control, the interest in NDP approach is enlarged and NDP algorithm is applied to diverse areas such as retailing, finance, inventory management, communication networks, etc. and it has been extended to chemical engineering parts. In the NDP approach, we select the optimal control input policy to minimize the value of cost which is calculated by the sum of current stage cost and future stages cost starting from the next state. The cost value is related with a weight square sum of error and input movement. During the calculation of optimal input policy, if the approximate cost function by using simulation data is utilized with Bellman iteration, the burden of calculation can be relieved and the curse of dimensionality problem of DP can be overcome. It is very important issue how to construct the cost-to-go function which has a good approximate performance. The neural network is one of the eager learning methods and it works as a global approximator to cost-to-go function. In this algorithm, the training of neural network is important and difficult part, and it gives significant effect on the performance of control. To avoid the difficulty in neural network training, the lazy learning method like k-nearest neighbor method can be exploited. The training is unnecessary for this method but requires more computation time and greater data storage. The pH neutralization process has long been taken as a representative benchmark problem of nonlin ar chemical process control due to its nonlinearity and time-varying nature. In this study, the NDP algorithm was applied to pH neutralization process. At first, the pH neutralization process control to use NDP algorithm was performed through simulations with various approximators. The global and local approximators are used for NDP calculation. After that, the verification of NDP in real system was made by pH neutralization experiment. The control results by NDP algorithm was compared with those by the PI controller which is traditionally used, in both simulations and experiments. From the comparison of results, the control by NDP algorithm showed faster and better control performance than PI controller. In addition to that, the control by NDP algorithm showed the good results when it applied to the cases with disturbances and multiple set point changes.