• Journal of Korean Society for Quality Management
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• v.15 no.1
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• pp.2-12
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• 1987

Warranty cost usually involves complex factors paticularly when the product concerned consists of a great deal of parts. In spite of that it can be assessed by means of rather simple mathematical expression, it is possible to realistically appraise the sensitivity to any type of quality policy. This paper thus presents the mathematical concept related to the warranty cost and the general relationship showing that quality policy can be established in connection with the economic quality level.

• Proceedings of the Safety Management and Science Conference
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• 2000.11a
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• pp.39-52
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• 2000

This paper is concerned with the method of estimating lifetime distribution for field data in warranty period and for a situation where some additional field data can be gathered after the warranty period. Implementing the proposed methods in this paper will result in obtaining the more precise product life time estimation and product improvement.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.675-675
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• 1995

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.62
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• pp.1-10
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• 2001

The electronics industry is fast growing segment of manufacturing and service industries. It is important that the manufacturer develops a product with adequate life cycle, high quality, and low failure rate in the specified time period. Environmental Stress Screening(ESS) and burn-in are widely used in the electronic industry to assist in the elimination of early failure. In this research, we construct optimal cost model of combined ESS and burn-in under various warranty policy and establish optimal testing times for given environments. Also we conduct sensitivity analysis on various parameter. The results of this study are summarized as follows. Comparing free warranty policy to rebate warranty policy, optimal ESS time is longer under free warranty policy, and optimal burn-in time is longer under rebate warranty policy. Free warranty policy higher than rebate warranty policy in total cost.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.12 no.3
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• pp.41-63
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• 2004

The area covered by product liability in broadest sense is so vast that an attempt to analyse all its impact on the aviation world risk. Every effort has been made to confine our review of subject a closely as possible to its influence on aircraft manufacturers, airlines and passengers, in spite of strong connections with other spheres of commercial. Product Liability in aviation is the liability of aircraft's manufacturer, processor or non-manufacturing seller for injury to the person or property of a buyer or third party caused by a product which has been sold. Here-in a product is aircraft, third party is passengers who suffered damage by defective design, defective construction, inadequate instructions for handling in aircraft. Whenever a product turns out to be defective after it has been sold, there are under Anglo-American law three remedies available against the aircraft's manufacturer (1) liability for negligence (2) breach of warranty (3) strict liability in tort. There are Under continental law Three remedies available against the aircraft's manufacturer (1) liability for defective warranty (2) liability for non-fulfillment of obligation (3) liability in tort. It is worth pointing out here an action for breach of warranty or for defective warranty, for non-fulfillment of obligation is available only to direct purchaser on the basis of his contract with the aircraft's manufacturer, which of course weakness its range and effectiveness. An action for tort offers the advantage of being available also to third parties who have acquired the defective product at a later stage. In tort, obligations are constituted not only by contract, but also by stature and common law. In conclusion, There in no difference in principle of law. In conclusion I would like to make few suggestions regarding the product liability for aircraft's manufacturer. Firstly, current general product liability code does not specify whether government offices(e.g. FAA) inspector conducted the inspection and auditory certificate can qualify as conclusive legal evidence. These need to be clarified. Secondly, because Korea is gaining potential of becoming aircraft's manufacturer through co-manufacturing and subcontracting-manufacturing with the US and independent production, there needs legislation that can harmonize the protection of both aircraft's manufacturers and their injured parties. Since Korea is in primary stage of aviation industry, considerate policy cannot be overlooked for its protection and promotion. Thirdly, because aircraft manufacturers are risking restitution like air-carriers whose scope of restitution have widened to strict and unlimited liability, there needs importation of mandatory liability insurance and national warranty into the product liability for aircraft's manufacturers. Fourthly, there needs domestic legislation of air transportation law that clearly regulates overall legal relationship in air transportation such as carrier & aircraft manufacturer's liability, and aviation insurance.

• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.1
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• pp.55-62
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• 1995

This paper compares the two policies which are unsed in Korean electronic appliance industry. Policy I is a general warranty policy under which all of failures during warrenty period (12 months) are repaired without charge. Policy II was proposed recently by a company. Under Policy II, when the product fails until a certain times(6 months), the failed product will be replaced by the new product and all other failures from the certain time to the warrenty period (24 months) will be repaired free. We obtain the expected total warranty costs per product and necessary conditions under which the Policy II has a meaning in economic point of view without or with discount rate. Some numericla examples are considered.

• Journal of Korean Society for Quality Management
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• v.15 no.1
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• pp.13-19
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• 1987

This paper discusses the methods of determining optimal warranty period for repairable goods. The demand of the product is assumed to increase with the length of the warranty period. Good-as-new repair and minimal repair models are considered. The method of obtaining optimal warranty period is explored when the failure distribution is an exponential or a Weibull. The case of discounting all associated costs continuously over time is also considered.

• Journal of Korean Society for Quality Management
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• v.24 no.2
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• pp.102-112
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• 1996

Estimation of warranty costs is an important application area of reliability engineering. On the manufacturer's point of view, exact estimation of warranty costs helps decisions on budgeting, product pricing, and A/S capacity planning, etc. We reviewed the state-of-the-art of existing models on warranty policies and suggested some future research directions.

• Journal of Korean Society for Quality Management
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• v.51 no.1
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• pp.1-18
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• 2023

Purpose: In Part 1, the purpose of this study is to examine how a used product provider optimizes a company's profits by comparing an extended warranty to a used product only when selling a product and what it provides later. In addition, in Part 2, an empirical study can confirm the structure in which extended guarantees can work effectively by grasping consumers' purchase intention according to the time of sale of extended guarantees, which is the basic premise of the analysis model of Part 1. Methods: This study aims to conduct not only analytical studies but also empirical studies applying various statistical analysis methods using questionnaires targeting customers and potential consumers who have subscribed to extended warranty services. Results: The study showed that the profits of companies providing extended warranty services were proportional to the coefficient of the extended guarantee service value, so it is necessary to create an environment in which the effect of extended guarantee services can be well realized. In the empirical model, the higher the emotional and economic benefits are perceived, the higher the purchase intention according to the future purchase of extended guarantees. Conclusion: Through this study, various problems that may be caused by the structural diversity of the supply chain providing extended warranties in the future can be viewed and contribute to the theoretical foundation for strategic understanding.

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