• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.835-842
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• 2001

We propose a software-reliability growth model incoporating the amount of testing effort expended during the software testing phase. The time-dependent behavior of testing effort expenditures is described by a Weibull curve. Assuming that the error detection rate to the amount of testing effort spent during the testing phase is proportional to the current error content, a software-reliability growth model is formulated by a nonhomogeneous Poisson process. Using this model the method of data analysis for software reliability measurement is developed. After defining a software reliability, we discuss the relations between testing time and reliability and between duration following failure fixing and reliability are studied in this paper. The release time making the testing cost to be minimum is determined through studying the cost for each condition. Also, the release time is determined depending on the conditions of the specified reliability. The optimum release time is determined by simultaneously studying optimum release time issue that determines both the cost related time and the specified reliability related time.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.386-386
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• 2022

우리나라에서는 '물의 재이용 촉진 및 지원에 관한 법률 시행규칙' 등 다양한 법률에 따라 특정 규모 이상의 시설에 빗물이용시설을 설치하도록 규정하고 있으며, 지자체에서는 빗물이용시설의 이용을 장려하고자 설치비 및 시설 운영비를 지원하고 있다. 현업에서 빗물이용시설의 설계는 간편식을 이용하여 목표 우수이용률 또는 공급보장률을 만족하는 용량으로 결정하고 있다. 또한, 산정된 빗물이용시설의 용량에 대해서만 경제성 분석을 하고 있으며, 경제성 분석에 포함된 수식에 대한 근거가 부족한 실정이다. 본 연구에서는 기 개발된 빗물이용시설 설계 프로그램인 CARAH(capacity design aid for rainwater harvesting)의 추가 기능으로 경제성 분석을 통한 빗물이용시설의 적정 용량 결정 도구 및 사용자 편의 환경 개발 결과를 제시하고자 한다. 본 연구를 통해 개발된 CARAH의 경제성 분석 도구는 빗물이용시설의 용량, 설치비, 유지보수비용, 지자체의 설치비 지원 및 빗물 이용에 따른 요금 감면액 등을 고려하여 빗물이용시설의 비용편익 비율(benefit cost ratio; BCR) 산정 결과를 제시하는 기능이다. 본 연구에서는 개발된 CARAH의 경제성 분석 도구를 이용하여 기 설치된 광교 신도시의 빗물저류조 5호를 대상으로 경제성 분석을 수행하였으며, 경제성을 고려한 적정 저류 용량을 제시하였다. 경제성 분석 기간은 빗물이용시설의 내용 연수인 30년으로 하였으며, 여러 목표 공급보장률에 따른 최소 저류 용량별 BCR 결과를 비교하여 광교 신도시의 빗물저류조 5호의 적정 저류 용량을 결정하였다. 그 결과, 공급보장률이 60%에 해당하는 저류 용량 341 m3의 BCR이 7.28로 가장 경제적인 빗물이용시설의 저류 용량으로 산정되었다.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.65-79
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• 2021

The purpose of this study was to research how emotional factors affect decision-making on the maintenance and abandonment of a patent, and to present new criteria for patent policies. The types of Korean patent abandonment were analyzed according to the patent holding period, and a questionnaire survey was carried out to verify whether there are differences among patentees in terms of sunk cost bias, endowment effect, and coupling or not. Individuals and small and medium-sized enterprises showed relatively greater emotional bias toward sunk cost and endowment effect than large companies, and the sunk cost effect decreased as decision-making experience increased. In addition, the reduction in the payment cycle of the patent renewal fee has a positive effect on the increase in the willingness to use the patent right, and the individuals and small and medium-sized enterprises has a greater synergistic effect than the case of large companies, in particular. This study are expected to play a part in establishing policies to minimize wasteful factors of patent assets based on the propensity of the patentees.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.477-480
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• 2003

The objective procedure and criterion needs to efficiently perform the safety assessment and improve reliability for results of the cost analysis. There are many studies about cost analysis of safety assessment, but the these studies have problems such as non-quantification of criterions and methods. The purpose of this study to suggest the procedure and criterion for successful cost analysis and quantify cost factors. First, in the cost analysis of the housing reconstruction that is presented this study, determinate the life-cycle and the discount rate, then estimate reconstruction cost and remodeling cost. Finally, compare the annual equivalent LCC of two costs for decision malting to reconstruction or remodeling.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.129-140
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• 2007

The planning procedure of a transit operation consists of design, operation, and evaluation according to the research characteristics. There are some review studies on the operation and evaluation procedure, but the research on the design procedure has not yet been organized systematically. In this study, the research on transit system design was reviewed and the model structure and its solution method were arranged. The decision variables of the design procedure are network structure, line spacing or position, stop spacing, dispatching headway, and fleet size. In the analytical research on design procedure, system total cost is generally used as the objective function. System total cost is comprised of user cost, which is the sum of user access, waiting, and travel cost, and operating cost. Total cost of the transit system, used as the objective function, has the unique minimum because it is differentiable. There is a certain decision variable that makes the derivative of the objective function equal to zero and the second derivative of the objective function is positive. Therefore the decision variable that makes the first derivative of the objective function zero is the optimum that minimizes the objective function, and each of the cost components of the objective function become the same. This study is expected to help understanding about the research on the design procedure of transit operation planning and to help be a catalyst for relevant research.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.32-39
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• 2018

Repairing timing and the extended service life with repairing are very important for cost estimation during operation. Conventionally used model for repair cost shows a step-shaped cost elevation without consideration of variability of extended service life due to repairing. In the work, RC(Reinforced Concrete) Column is considered for probabilistic evaluation of repairing number and cost. Two mix proportions are prepared and chloride behavior is evaluated with quantitative exterior conditions. The repairing frequency and cost are investigated with varying service life and the extended service life with repairing which were derived from the chloride behavior analysis. The effect of COV(Coefficient of Variation) on repairing frequency is small but the 1st repairing timing is shown to be major parameter. The probabilistic model for repairing cost is capable of reducing the number of repairing with changing the intended service life unlike deterministic model of repairing cost since it can provide continuous repair cost with time.

• Journal of Digital Convergence
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• v.15 no.3
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• pp.87-98
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• 2017

As the market for coffee chains becomes fierce, it is important for coffee chains to establish an enduring relationship with customers and encourage them to revisit their stores. Thus, it becomes important to understand consumers' repurchase decision-making mechanisms in the context of coffee chains. Customer satisfaction, perceived switching costs, and regret were considered as the main factors of customers' repurchase intentions. Especially, the effect of regret experience of coffee chains on consumers' repurchase decision was examined. In addition, coffee quality, physical environment quality, service encounters performance, and brand trust were considered as attributes of coffee shop selection, and their effects on customer satisfaction and perceived switching cost were investigated. The results of the study showed that customer satisfaction and perceived switching costs had a positive effect on repurchase intention, while regret had a negative effect on repurchase intention. Coffee quality and physical environmental quality had no significant effect on customer satisfaction and perceived conversion cost. Service encounter performance had a significant impact on perceived switching costs alone. Brand trust had a significant impact on both customer satisfaction and perceived switching cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.325-332
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• 2002

In the process of designing pareto optimal insurance contract, it is necessary to assume that insurance contract conditions are endogenous to build a model. The expected utility, the non-expected utility and the state-dependent utility function can be applied as a insurance decision making principle. The insurance costs may have the linear, convex, and concave ralationship with the indemnity schedule. However, the sunk cost and fixed cost must be recognized. The deductible which decides whether an insurance contract to be a full or partial insurance contract can exist in the forms of straight deductible or diminishing deductible. Indeciding the level of deductible, the types of the insurance and the risks to be insured should be the deciding factors. Especially for recall insurance, there is relatively high chance that the recalling company being bankrupt. Therefore, the possibility of bankrupcy should be the considering factor in deciding the policy limit. The existence of the incomplete market and uninsurable background risk should be understood as restricting conditions of the pareto-optimal insurance contract.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.63-68
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• 2006

Cyber Attacks have increased damages constantly in all over the world for several years. A survey said the cost caused by Cyber Attacks had increased 225 times from 1996 to 2003. It is very difficult to calculate the cost by the Attacks exactly but the calculating the cost of cyber attacks would be great helpful for a company to decide how much budget to spend to Information Security. In this research we could reach the conclusion : the cyber attacks has decreased the stock price of the companies, especially pure internet companies. But the stock market has not greatly impacted by the types of Cyber Attacks. Korean stock market also impacted by the Internet Destruction Accident happened Jan. 25. 2003. On the basis of this study we will recommend a policy or a regulation which force board of directors and officers of a company to have information security liability.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.547-559
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• 2003

In this study, a mathematical model is developed for sewer rehabilitation planning by considering cost and inflow/infiltration. A sewer rehabilitation planning model is required to decide the economic life of the sewer by considering trade-off between cost and inflow/infiltration. And it is required to find the optimal rehabilitation timing, according to the cost effectiveness of each sewer rehabilitation within the budget. To solve the problem, we formulated a multiple objective mixed integer programming(MOMIP) model based on network flow optimization. The network is composed of state nodes and arcs. The state nodes represent the remaining life and the arcs represent the change of the state. The model considers multiple objectives which are cost minimization and minimization of inflow/infiltration. Using the multiple objective optimization, the trade-off between the cost and inflow/infiltration is presented to the planner so that a proper sewer rehabilitation plan can be selected.