• Proceedings of the Korea Multimedia Society Conference
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• 1998.10a
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• pp.202-207
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• 1998

The network reliability is to be computed in terms of the terminal reliability. The computation of a terminal reliability is started with a Boolean sum of products expression corresponding to simple paths of the pair of nodes. This expression is then transformed into another equivalent expression to be a Disjoint Sum of Products form. But this computation of the terminal reliability obviously does not consider the communication between any other nodes but for the source and the sink. In this paper, we derive the overall network reliability which all other remaining nodes. For this, we propose a method to make the SOP disjoint for deriving the network reliability expression from the system success expression using the modified Sheinman's method. Our method includes the concept of spanning trees to find the system success function by the Cartesian products of vertex cutsets.

• International Journal of Reliability and Applications
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• v.3 no.4
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• pp.155-164
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• 2002

This paper focuses on how modem data mining can be integrated with real-time relational databases and commercial data warehouses to improve reliability in real-time. An important Issue for many manufacturers is the development of relational databases that link key product attributes with real-time process parameters. Helpful data for key product attributes in manufacturing may be derived from destructive reliability testing. Destructive samples are taken at periodic time intervals during manufacturing, which might create a long time-gap between key product attributes and real-time process data. A case study is briefly summarized for the medium density fiberboard (MDF) industry. MDF is a wood composite that is used extensively by the home building and furniture manufacturing industries around the world. The cost of unacceptable MDF was as large as 5% to 10% of total manufacturing costs. Prevention can result In millions of US dollars saved by using better Information systems.

• Journal of Applied Reliability
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• v.13 no.3
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• pp.175-190
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• 2013

This study considers reliability growth management as the excellent method for construction equipment development with the effect on decreasing COPQ(Cost of Poor Quality Cost) of new products. MIL-HDBK-189A(1981) and RADC-TR-84-20(1984) standards provide a general concept of reliability growth management including to reliability growth test, models and FRACAS(Failure Reporting and Corrective Action System). There is no study how to apply reliability growth management to construction equipment(or machine) development. This paper propose the method to apply it to construction equipment development process from the reliability target setting for developing products to launching them at market. It is expecially showing how to set target reliability for new developing equipment and the development risk to reach the reliability target in detail.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.385-388
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• 2000

The computation of a terminal-pair reliability is started with a Boolean sum of products expression corresponding to simple paths of the pair of nodes. This expression is then transformed into another equivalent expression to be a Sum of Disjoint Products form. The terminal reliability can then be obtained in a straightforward manner from the Sum of Disjoint Products form. In this paper, we proposed an efficient method to obtain reliability expressions for calculating multiple K terminal-pairs reliability between terminal-pairs of nodes of computers of complex networks. Actual programming results show that the new method is superior with regard to computational efficiency, especially for computing the reliability of multiple terminals.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1914-1917
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• 2005

Recently, the reliability evaluation and analysis are applied for many industrial products, and many products are required to guarantee in quality and in efficiency. The purpose of this paper is to present some of reliability evaluation methodologies that are applicable to machine tools. Especially ATC(Automatic Too Changer), which is core component of line center, was chosen as the target of the reliability evaluation and analysis. The scope of research is reliability prediction, reliability test and evaluates their results. The results of this research has shown the failure rate, MTBF(Mean Time Between Failure), reliability for those components and real tests reliability through constructed reliability test-bed. It is expected that proposed methodologies will increase reliability for high speed line center.

• Proceedings of the Safety Management and Science Conference
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• 2004.11a
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• pp.259-267
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• 2004

Enterprise must establish a properly competitive strategy according to environmental changes and international competitions. It is necessary to develop the strategy of competitive power for an efficient operation as well as system, industry, product and price competitions. This paper aims to propose a choice method of Competitive Power Key Factors which can be applied to unit parts and finished products, construction products, soft wear products based on Reliability.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.205-212
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• 2003

Reliability means that certain parts or systems maintain its best qualities and functionalities within certain periods and is the prospective quality which the safe life of products is indicated by quantitative values and the highest level of reliability of the products is required to attain in the highly competitive business world. In Korea, there have been a significant growth in the field of reliability and government promotes the "Reliability Improvement Project" to establish infrastructure to conduct reliability assessment and certification. The importance and necessity is well recognized among researchers and engineers working in the research institutions and the manufacturing industries and many industries invest a great amount of money and effort in improving the reliability of its products. In this paper, the promotional status of reliability improvement project and necessity of establishment of the reliability certification system for aerospace field is presented.

• Proceedings of the Korean Reliability Society Conference
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• 2002.06a
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• pp.275-279
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• 2002

A Bayesian acceptance sampling plan for limited failure populations are developed. We consider a situation where defective products have short lifetimes and non-defective ones never fail during the technological life of the products. An acceptance criterion which guarantees the out going quality of accepted products is derived using the prior information on the quality of lots submitted for inspection. Numerical examples are provided.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1327-1335
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• 2011

Recently, also in railway vehicles, related products are being designed and manufactured through RAMS activities in order to secure their reliability, availability, maintainability & safety. Subway operators are conducting R&D on various preventive maintenance methods and applying them to the field so as to establish a reliability centered maintenance(RCM) system. In this connection, manufacturers shall carry out R&D based on reliability from the first design stage of development to provide high quality products to subway operators. And operators shall have the products operated properly to their particular operating environment and managed based on the standard maintenance manual. Not only that, but the related field data shall be fed back into the manufacturers to upgrade upcoming products by organic cooperation between manufacturer and operators. However, the mutually beneficial cooperative relationship is not still developed in the domestic railway industry. In terms of methodology for life prediction, this study was intended to analyze field data on relays used for rolling stocks considering operational characteristics in the position of subway operators and predict parts reliability using reliability prediction program from the standpoint of manufacturers as well.

• Proceedings of the Korean Reliability Society Conference
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• 2001.06a
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• pp.235-238
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• 2001

It is well known that the reliability of materials of mechanical products is becoming more and more important not only for assurance of quality, but for international competition of products. In order to assure the reliability of materials or mechanical products nondestructive evaluation (NDE) techniques are playing more important roles. The existence of Internal defects in materials or mechanical parts is served as crack initiation site during the various loading condition. Historically, nondestructive evaluation (NDE) technique has been used almost exclusively for detecting microscopic discontinuities In materials or mechanical parts after they have been in service to expand the role of the NDE to include all aspects of materials production and application. Research efforts are being directed at developing and perfecting NDE techniques capable of monitoring (1) materials production processes (2) material integrity following transport, storage and fabrication and (3) the amount and rate of degradation during service. In addition, efforts are underway to develop technique capable of quantitative discontinuity sizing, permitting determination of response using fracture mechanics analysis, as well as techniques for quantitative materials characterization to replace the qualitative techniques used in the past. In this paper, the important role of NDE technology for reliability assurance of materials/mechanical parts is introduced.