• Journal of Applied Reliability
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• v.12 no.4
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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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.33
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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.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.4
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• pp.280-293
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• 2005

In this study, a model to calculate the expected total construction cost has been developed by combining a model to calculate the sliding distance of a caisson of a vertical breakwater and a model to calculate the rehabilitation cost of a caisson. The optimal cross-section of a caisson of a vertical breakwater is defined as the cross-section that requires a minimum expected total construction cost within the allowable limit of caisson sliding. Two allowable limits are considered: 0.1 m of the expected sliding distance during the lifetime of the breakwater and 0.1 of the probability that the cumulative sliding distance during the lifetime of the breakwater is greater than 0.3 m. A discount rate has also been introduced to convert the future rehabilitation cost to the present value. The introduction of the discount rate reduces the expected total construction cost for the caissons designed for shorter return periods due to frequent rehabilitations. The present design method requires a smaller cross-section than the conventional deterministic method in shallow water depths, enabling us to design a caisson more economically. On the other hand, the above-mentioned allowable limits of caisson sliding show similar results for smaller water depths, while, for larger depths, the former requires a larger cross-section than the latter.

• Journal of Applied Reliability
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• v.11 no.4
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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.

• Journal of Integrative Natural Science
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• v.14 no.4
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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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• v.4 no.2
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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.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.10a
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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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• v.12 no.6
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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 ${\leq}80%$.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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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.