• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.777-783
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• 2007

Life cycle costing is one of the most effective cost approaches when we choose a solution from series of alternative so the least long-term cost ownership is achieved. Life cycle costing in railway industry has been focused on the prediction of investment for railway vehicles. But in today, the life cycle cost, LCC, prediction on the aspect of operation and maintenance cost through whole life cycle is highly necessary. In this paper, we present a strategy for the development of life cycle cost estimation software on the aspect of maintenance strategies of railway vehicle. For this purpose, we suggested a structure of LCC software based on the UNIFE LCC model. And we developed a pilot version of software to evaluate the LCC model that we suggested for railway vehicle. We performed LCC analysis on the brake module of metro vehicle in case study and concluded that the software and model developed in this research could enough to support engineers in choosing better cost effective solutions from many alternatives.

• Journal of Information Technology Applications and Management
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• 제15권3호
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• pp.195-208
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• 2008

In an emergency management case, evaluating the economic value of information technology investments is a challenging problem due to the effects of decision making, uncertainty of disasters, and difficulty of measurements. Risk assessment and recovery process, one of the major functions in emergency management, consists of (1) measurement of damages or losses, (2) recovery planning, (3) reporting and approving budgets, (4) auctioning off recovery projects to constructors, and (5) construction for the recovery. Specifically and of our interest, measurement of damages or losses is often a costly and time-consuming process because the wide range of field surveys should be performed by a limited pool of trained agents. Managers, therefore, have to balance accuracy of the field survey against the total time to complete the survey. Using information technologies to support field survey and reporting has great potential to reduce errors and lowers the cost of the process. However, existing cost benefit analysis framework may be problematic to evaluate and justify the IT investment because the cost benefit analysis often include the long-run benefit of IT that is difficult to quantify and overlook the impact of managerial control upon the investment outcomes. Therefore, we present an alternative cost-centric control model that conservatively quantifies all cost savings to replace benefits in cost benefit analysis and incorporate the managerial control. The model provides a framework to examine how managerial decision making and uncertainty of disaster affect the economic value of IT investments. The current project in Emergency Agency in South Korea is introduced as a case to apply the cost-centric control model. Our work helps managers to better evaluate and justify IT-related investment alternatives in emergency management.

• 품질경영학회지
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• 제43권4호
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• pp.533-544
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• 2015

Purpose: The purpose of this study is to analyze the cost efficiency of food industry in JeollaNamdo. And this study is focused on the correlation between the economic efficiency of food industry and its cost efficiency, based on the analysis of 372 food companies' data in JeollaNamdo in 2012. Methods: DEA cost minimization is the measurement of the cost efficiency of JeollaNamdo food industry in 2012. In this study, the CCR and BBC models have been employed to analyze the decomposing cost efficiency-technical efficiency, allocative efficiency, and scale efficiency respectively. And the Spearman rank correlation and Wilcoxon signed rank test also have been employed to check the correlation and difference between the ranking orders based on the efficiency scores respectively. Results: For the CCR model, mean cost efficiency was found to be 0.084(0.54 for allocative efficiency and 0.19 for technical efficiency). For the BCC model, mean cost efficiency was found to be 0.252(0.453 for allocative efficiency and 0.564 for technical efficiency). Average scale efficiency was found to be 0.38. In analyzing the results, this study argues that the optimal way to improve cost efficiency is by reducing inputs proportionally and changing their combination. Conclusion: The efficiency scores of the two models show high correlation, whereas, the differences between them are also found to be significant. Hence, it should be cautious to select a suitable model when we do the research.

• Journal of the Korean Data and Information Science Society
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• 제14권2호
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• pp.393-403
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• 2003

In this paper, various replacement policies for the general failure model are considered. There are two types of failure in the general failure model. One is Type I failure (minor failure) which can be removed by a minimal repair and the other is Type II failure (catastrophic failure) which can be removed only by a complete repair. In this model, when the unit fails at its age t, Type I failure occurs with probability 1-p(t) and Type II failure occurs with probability p(t), $0{\leq}p(t){\leq}1$. Under the model, optimal replacement policies for the long-run average cost rate and the limiting efficiency are considered. Also taking the cost and the efficiency into consideration at the same time, the properties of the optimal policies under the Cost-Priority-Criterion and the Efficiency-Priority-Criterion are obtained.

• 전기학회논문지
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• 제65권6호
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• pp.979-986
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• 2016

At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.

• 대한전기학회논문지:전력기술부문A
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• 제50권9호
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• pp.431-439
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• 2001

This Paper illustrates a new numerical analysis method using a nodal effective load model for nodal probabilistic production cost simulation of the load point in a composite power system. The new effective load model includes capacities and uncertainties of generators as well as transmission lines. The CMELDC(composite power system effective load duration curve) based on the new effective load model at HLll(Hierarchical Level H) has been developed also. The CMELDC can be obtained from convolution integral processing of the outage capacity probabilistic distribution function of the fictitious generator and the original load duration curve given at the load point. It is expected that the new model for the CMELDC proposed in this study will provide some solutions to many problems based on nodal and decentralized operation and control of an electric power systems under competition environment in future. The CMELDC based on the new model at HLll will extend the application areas of nodal probabilistic production cost simulation, outage cost assessment and reliability evaluation etc. at load points. The characteristics and effectiveness of this new model are illustrated by a case study of MRBTS(Modified Roy Billinton Test System).

• 품질경영학회지
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• 제17권2호
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• pp.17-26
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• 1989

This paper is concerned with forecasting the existing number of errors in the computer software and optimizing the stopping time of the software test based upon the forecasted number of errors. The most commonly used models have assessed software reliability under the assumption that the software failure late is proportional to the current fault content of the software but invariant to time since software faults are independents of others and equally likely to cause a failure during testing. In practice, it has been observed that in many situations, the failure rate decrease. Hence, this paper proposes a mathematical model to describe testing situations where the failure rate of software limearly decreases proportional to testing time. The least square method is used to estimate parameters of the mathematical model. A cost model to optimize the software testing time is also proposed. In this cost mode two cost factors are considered. The first cost is to test execution cost directly proportional to test time and the second cost is the failure cost incurred after delivery of the software to user. The failure cost is assumed to be proportional to the number of errors remained in the software at the test stopping time. The optimal stopping time is determined to minimize the total cost, which is the sum of test execution cast and the failure cost. A numerical example is solved to illustrate the proposed procedure.

• 한국생활과학회지
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• 제21권6호
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• pp.1173-1184
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• 2012

This study estimates a structural model to examine the causal relationships among web browsing, switching cost, and site retention in the context of apparel shopping website. A total of 499 usable questionnaires were obtained from consumers aged from 20 to 49 years. For data analysis, exploratory factor analysis, confirmatory factor analysis and structural model were used. The result showed that consumer's perceived switching costs consisted of three factors: relationship cost, search cost and benefit loss cost. In estimated structural model, the relationship cost was influenced by leisure browsing; the search cost was influenced by informational browsing and leisure browsing; the benefit loss cost was influenced by leisure browsing. Especially, the leisure browsing was the most highly related to the benefit loss cost, and followed by relationship cost and search cost. However, hedonic browsing was not significantly related the factors of switching costs. The search costs significantly affected customer's intentions for site retention. A managerial implication was discussed for e-retailers in order to develop strategic switching costs in building long-term relationships with web browsers on the apparel shopping websites.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.212-215
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• 2008

건축공사의 공사비 절감은 시공단계보다 사업초기단계 및 설계단계에서 정확한 공사비 예측을 함으로써 더욱 효율적으로 절감될 수 있다. 하지만 현행 공공 건설공사의 공사비 산정 및 관리는 실시설계 이후로 집중되어 있어, 계산견적을 중심으로 실시되는 기획 및 기본설계단계에서의 사업비관리는 매우 취약하다고 볼 수 있다. 이에 본 연구에서는 현행 공사비 산정 방법의 문제점 및 실적공사비 사례정보 분석하여 기본설계단계에서 구체적 비용 계획을 세우고 이에 부합되는 설계가 진행되는지 검토 가능한 공사비 산정모델 개발을 위한 예비적 연구를 수행하였다.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.696-706
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• 2013

본 연구는 DEA모형에 바탕을 둔 표준원가에 기초한 원가차이 분석의 개념을 구현할 수 있는 모형을 설계하고 69개 종합병원의 투입 산출물을 이용해 효율성 분석과 원가관리 방안을 살펴보았다. 이를 위해 DEA모형을 통해 달성가능한 목표원가를 구하고 이를 실제원가와 비교하여 차이분석모형의 틀을 구축하였다. 또한 이 모형을 바탕으로 의사 간호사 인건비 정보를 구해 2008년도 결산기준 69개 종합병원의 표준원가차이를 구하고 이를 기술적 비효율성으로 인한 원가차이, 가격 비효율성에 기인한 원가차이, 표준예산원가 원가차이로 분리하여 원가관리의 새로운 방식을 제시할 수 있었다. 또한 실증분석을 통해 69개 종합병원은 병상수와 같은 규모를 늘리는 것이 효율성 개선에 기여하지 않으며 오히려 예산목표원가 관리 측면에서는 비효율적인 것으로 나타나 규모 확장 일변도의 전략을 수정할 필요가 있는 것으로 나타났다.