• Journal of the Korean Data and Information Science Society
• /
• v.23 no.6
• /
• pp.1195-1202
• /
• 2012

In this paper, we determine the expected total cost from the user's perspective for the replacement model with the extended warranty when minimal repair cost is a function of failure time. To do so, we define the extended warranty and assume the replacement model following the expiration of extended warranty from the user's perspective. Especially, we propose the criterion to buy the extended warranty and the numerical examples are presented to illustrate the purpose when the failure time of the system has a Weibull distribution.

• Journal of Applied Reliability
• /
• v.8 no.1
• /
• pp.1-13
• /
• 2008

A methodology for collection and analysis of automotive field reliability data is presented. Automotive warranty system usually covers a pre-determined period of time and/or mileage accumulation. Therefore mileage information for the vehicles that have not experienced any failure or problems during the warranty period is not available. In this paper, a reliability analysis method using the estimated mileage distribution from an additional survey for vehicles that have not any record during the warranty period is proposed. Methods of reliability analysis using the warranty information collected under the EU and US warranty policies are also provided.

• Communications for Statistical Applications and Methods
• /
• v.17 no.6
• /
• pp.865-877
• /
• 2010

This paper considers the periodic preventive maintenance model for a repairable system following warranty expiration. We consider three types of warranty policies: free repair warranty, pro-rata repair warranty, and combination repair warranty. Under these preventive maintenance models, we derive the expressions for the expected cycle length, the total expected cost, and the expected cost rate per unit time. In addition, we explain the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for a Weibull distribution case.

• International Journal of Reliability and Applications
• /
• v.3 no.3
• /
• pp.113-124
• /
• 2002

This paper suggests the optimal periodic preventive maintenance policies after the combination warranty is expired. After the combination warranty is expired, a repairable system undergoes PM periodically and is minimally repaired at each failure. And also the system is replaced by a new system at the N th PM. In this case, we derive the mathematical formula for the expected cost rate per unit time. The optimal number and period for the periodic PM that minimize the expected cost rate per unit time are obtained. Some numerical examples are presented for illustrate purpose.

• Journal of the Korean Data and Information Science Society
• /
• v.13 no.1
• /
• pp.55-65
• /
• 2002

In this paper we present a Bayesian approach for determining an optimal maintenance policy following the expiration of warranty for a repairable system. We consider two types of warranty policies : non-renewing free replacement warranty (NFRW) and non-renewing pro-rata warranty (NPRW). The mathematical formula of the expected cost rate per unit time is obtained for NFRW and NPRW, respectively. When the failure time is Weibull distribution with uncertain parameters, a Bayesian approach is established to formally express and update the uncertain parameters for determining an optimal maintenance policy. We illustrate the use of our approach with simulated data.

• Journal of Applied Reliability
• /
• v.13 no.4
• /
• pp.229-239
• /
• 2013

This paper reports a manner to use a Bayesian approach to derive the optimal replacement policy. In order to produce a system with minimal repair warranty, a replacement model with the extended warranty is considered. Within the warranty period, the failed system is minimally repaired by the manufacturer at no cost to the end-user. The failure time is assumed to follow a Weibull distribution with unknown parameters. The expected cost rate per unit time, from the end-user's viewpoints, is induced by the Bayesian approach, and the optimal replacement policy to minimize the cost rate is proposed. Finally, a numerical example illustrating to derive the optimal replacement policy based on the Bayesian approach is described.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.05a
• /
• pp.266-267
• /
• 2017

As apartment buildings defect lawsuits become socioeconomic problems, an objective basis system for the term of warranty liability of reinforced concrete constructions is urgent. This study was carried out as a basic study for developing a basis system for the term of warranty liability. To do this, defect data actual collected in apartment complexes were collected and analyzed. As the result of checking the cumulative rate of defect occurrence in reinforced concrete construction by year, the point of time of reaching the 90% level was the 5th years, which was similar with the provision of the Apartment Building Management Act. However, the current Supreme Court precedent has decided that the term of warranty liability for the main structural parts in reinforced concrete construction shall be 10 years and the dispute is expected to continue in the future in the defect lawsuit.

• Journal of Korean Society for Quality Management
• /
• v.40 no.1
• /
• pp.39-48
• /
• 2012

An early detection system for warranty issues periodically collects customers' claim data and automatically reports alarms about emerging issues based on statistical algorithms. It helps companies to reduce an issue definition time and save the handling cost of warranty claims. This paper provides an evaluation framework to validate the economic effect of an early detection system project. For this purpose, we present economical index of a project with explicit formulas such as ROI(return on investment), PP(payback period), NPV(net present value), PI(profitability index) and IRR(internal rate of return) and analyze the sensitivities of the index according to the variation of project input parameters. The proposed analysis framework is expected to be used for evaluating economic values of various system integration projects.

• Journal of the Korea Institute of Building Construction
• /
• v.18 no.2
• /
• pp.195-202
• /
• 2018

The defects that are bound to arise in most construction projects cause disputes among the contracting parties regarding the defect warranty liability (DWL)guaranteed by the retention of the contractor's performance security at the end of the performance period of the contract. Most current projects involve a multiple-tier contractual relationship, causing the liability for some defects to overlap. In addition, many construction projects are made up of multiple detailed work types which an expert hired by the owner inspects the part completed by the contractor and pays an interim payment. However, after the completion of work, the contractor will still hold the defect warranty liability. In a scenario in which the work is delayed due to reasons for which the owner is responsible, the defect warranty liability period is also increased, imposing an additional burden on the contractor. In this study, basic research was carried out with the goal of reducing problems related to defect warranty liability Problems related to defect warranty liability cases and the nature of the defect warranty liability period were investigated. Possible solutions to the problems caused by the DWL that were suggested include the separation of the negligence liability period and the strict liability period, as well as the introduction of a retention money system.

• Journal of Information Processing Systems
• /
• v.6 no.2
• /
• pp.209-218
• /
• 2010

Classical warranty plans require crisp data obtained from strictly controlled reliability tests. However, in a real situation these requirements might not be fulfilled. In an extreme case, the warranty claims data come from users whose reports are expressed in a vague way. Furthermore, there are special situations where several characteristics are used together as criteria for judging the warranty eligibility of a failed product. This paper suggests a fast reasoning model based on fuzzy logic to handle multi-attribute and vague warranty data.