• 한국신뢰성학회지:신뢰성응용연구
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• 제12권4호
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• pp.255-263
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• 2012

This paper considers the cost analysis from the manufacturer's point of view for renewing replacement and non-renewing repair warranty(RRNRW) of a repairable system. To do so, we consider the renewing replacement and non-renewing repair warranty, which is proposed by Jung(2011). To analysis the expected warranty cost from the manufacturer's perspective for renewing replacement and non-renewing warranty, we obtain the expected total warranty cost and the expected warranty length which are very important information for the manufacturer. Finally, the numerical examples are presented for illustrative purpose.

• 산업경영시스템학회지
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• 제37권1호
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• pp.96-103
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• 2014

A steady-state controllable M/G/1 queueing model operating under the (TN) policy is considered where the (TN) policy is defined as the next busy period will be initiated either after T time units elapsed from the end of the previous busy period if at least one customer arrives at the system during that time period, or the time instant when Nth customer arrives at the system after T time units elapsed without customers' arrivals during that time period. After deriving the necessary system characteristics such as the expected number of customers in the system, the expected length of busy period and so on, the total expected cost function per unit time in the system operation is constructed to determine the optimal operating policy. To do so, the cost elements associated with such system characteristics including the customers' waiting cost in the system and the server's removal and activating cost are defined. Then, the optimal values of the decision variables included in the operating policies are determined by minimizing the total expected cost function per unit time to operate the system under consideration.

• 산업경영시스템학회지
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• 제18권33호
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• pp.153-160
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• 1995

This paper presents the parallel-type inventory structure using an order-up-to level inventory control system for analyzing the approximation of the expected units backordered and the measure of service. The rate of total expected backorders which is the measure of disservise, is given by dividing the improved units of total expected backorder into the total demand during an order cycle. the average annual total cost in system is obtained by considering the results. Total backorder model for the system without redistribution and the system with redistribution is described.

• 한국해안해양공학회지
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• 제17권4호
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• pp.280-293
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• 2005

본 연구에서는 직립 방파제 케이슨의 활동량 산정 모델과 케이슨 복구비용 계산 모델을 결합하여 기대 총 건설비 산정 모델을 수립하였다. 직립 방파제 케이슨의 최적 단면은 활동량의 허용 범위 내에서 기대 총 건설비가 최소가 되는 단면으로 정의된다 활동량의 허용 범위는 방파제 수명 동안의 기대 활동량을 0.1m로 하는 경우와 방파제 수명 동안의 누적 활동량이 0.3 m를 초과하는 확률을 0.1 이내로 하는 경우를 고려하였다. 또한 할인율 개념을 도입하여 미래 가치로 산정된 복구비용을 현재가치로 환산하였다. 작은 재현주기에 대해서 설계된 케이슨의 경우 잦은 복구 활동으로 인해 할인율을 적용했을 때의 기대 총 건설비용이 할인율을 적용하지 않았을 때보다 작아진다. 수심이 얕을 때 본 설계법이 기존의 결정론적 설계법보다 더 작은 단면을 요구하여 경제적인 설계가 가능하다. 한편, 수심이 얕을 때는 전술한 활동량 허용 기준들이 비슷한 결과를 나타내지만, 깊은 수심에서는 전자가 후자보다 더 큰 단면을 요구한다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권4호
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• pp.409-417
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• 2011

In this paper, we consider a replacement model following the expiration of warranty. In other words, this paper proposes the optimal replacement policy for a repairable system following the expiration of payable renewing replacement-non-renewing minimal repair warranty. The expected cost rate per unit time from the user's perspective is used to determine the optimality of the replacement policy. Thus, we derive the expressions for the expected cycle length and the expected total cost to obtain the expected cost rate per unit time. Finally, the numerical examples are presented for illustrative purpose.

• 통합자연과학논문집
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• 제14권4호
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• pp.197-204
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• 2021

Under the two-phase warranty, the warranty period is divided into two intervals, one of which is for renewing replacement warranty, and the other is for minimal repair warranty. Jung^[13] discusses the two types of extended two-phase warranty models. In this paper, we suggest the replacement model after the extended two-phase warranty that has been proposed by Jung^[13]. To determine the optimal replacement policy, we adopt the expected cost rate per unit time. So, the expressions for the total expected cost, the expected length of the cycle and the expected cost rate per unit time from the user's point of view are derived. Also, we discuss the optimal replacement policy and the uniqueness of the solution for the optimization. Furthermore, the numerical examples are provided to illustrate the proposed the replacement model.

• Management Science and Financial Engineering
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• 제4권2호
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• pp.59-75
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• 1998

This paper presents an incentive system to reduce response time from a supplier. The incentive system is expressed as a contract between an assembler and a supplier who have a long-term relationship. We produce the optimal payment scheme and expected total cost, when the assembler is farsighted. We show that the farsighted assembler obtains higher effort level from the supplier than the myopic assembler. We also show that the expected total cost of the farsighted assembler is smaller in the long run, although it is initially higher than that of the myopic assembler.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 가을 학술발표회 논문집
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• pp.152-159
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• 1994

One of the main objectives of the study is to propose a pratical and realistic reliability analysis by ETCM(Expected Total Cost Minimization). This study is intended to propose the safety assesment and capacity rating of existing reinforced concrete members by evaluating the safety evaluation index, that is RF(Rating Factor) from the results of the field test and inspection for 5 reinforced concrete bridges. ETCM method is used for the reliability analysis of the proposed models. The proposed reliability model and method are applied the safety assesment and system factors of reinforced concrete members.

• Gut and Liver
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• 제12권6호
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• pp.648-654
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• 2018

Background/Aims: Dual priming oligonucleotide-based multiplex polymerase chain reaction (DPO-based PCR) can detect the presence of clarithromycin resistance without culture. The aim of this study was to investigate the cost-effectiveness of DPO-based PCR for Helicobacter pylori eradication. Methods: From 2015 to 2016, medical records of patients who received H. pylori eradication therapy were analyzed. Patients were divided into two groups: tailored group patients who were treated based on DPO-based PCR and empirical group patients. Eradication rate and medical cost, including diagnostic tests, eradication regimens, and $^{13}C$-urea breath tests, were compared between the two groups. Cost for one successful eradication was calculated in each group. The expected cost of eradication for empirical treatment was investigated by varying the treatment duration and eradication rate. Results: A total of 527 patients were analyzed (tailored group 208, empirical group 319). The eradication success rate of the first-line therapy was higher in the tailored group compared to that in the empirical group (91.8% vs 72.1%, p<0.01). The total medical cost for each group was $114.8{\pm}14.1U.S.$ dollars (USD) and $85.8{\pm}24.4USD$, respectively (p<0.01). The total medical costs for each ultimately successful eradication in the tailored group and in the empirical group were 120.0 USD and 92.4 USD, respectively. The economic modeling expected cost of a successful eradication after a 7- or 14-day empirical treatment was 93.8 to 111.4 USD and 126.3 to 149.9 USD, respectively. Conclusions: Based on economic modeling, the cost for a successful eradication using DPO-based PCR would be similar or superior to the expected cost of a successful eradication with a 14-day empirical treatment when the first-line eradication rate is ${\leq}80%$.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.109-114
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• 2000

In this paper, an optimum design model for minimizing the life-cycle cost (LCC) of high-speed railway steel bridges is proposed The point is that it takes into account service life process as a whole, and thus the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs, expected strength failure costs and expected serviceability failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. By processing the optimum LCC design the effective and rational basis is proposed for calculating the total LCC and the sensitivity analysis of LCC is peformed. Based on a numerical example, it may be positively stated that the optimum LCC design of high-speed railway steel bridges proposed in this study provides a lot more rational and economical design, and thus the proposed approach will expedite the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.