• International Journal of Reliability and Applications
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• v.14 no.1
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• pp.41-54
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• 2013

In this paper, cost analysis is conducted using inter-failure interval under renewable warranty subject to imperfect repair for multi-component system. One way to model the imperfect repair is to use the quasi-renewal process (Wang and Pham 1996). Two alternative quasi-renewal processes were suggested by Park and Pham (2010) using quasi-renewal process; first is an altered quasi-renewal process with random variable parameter and second is a mixed quasi-renewal process considering replacement service and repair service, simultaneously. In this study, we use the altered and mixed quasi-renewal processes and develop the warranty cost model to obtain the expected value of warranty cost and to help company make important decisions regarding the warranty policy. Numerical examples are used to demonstrate the applicability of the methodology derived in the paper.

• Proceedings of the Korean Statistical Society Conference
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• 2002.11a
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• pp.125-128
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• 2002

In this paper, we define an availability of network, when the states of links are modeled by alternating renewal processes. The actual availabilities of some simple networks are obtained and compared to each other.

• Journal of the Korean Data and Information Science Society
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• v.16 no.1
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• pp.165-172
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• 2005

In recently, Popova and Wu(1999) proved a theorem which presents the long-run average fuzzy reward per unit time. In this note, we improve this result. Indeed we will show uniform convergence of a renewal reward processes with respect to the level ${\alpha}$ modeled as a fuzzy random variables.

• Journal of the Korean Data and Information Science Society
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• v.17 no.1
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• pp.195-204
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• 2006

In this paper, we consider a renewal process in which both the inter-arrival times and rewards are fuzzy random variables. We prove the uniform levelwise convergence of fuzzy renewal and fuzzy renewal rewards. These results improve the result of Popova and Wu[European J. Oper. Research 117(1999), 606-617] and the main result of Hwang [Fuzzy Sets and Systems 116 (2000), 237-244].

• Journal of applied mathematics & informatics
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• v.33 no.5_6
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• pp.607-625
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• 2015

Recently, Wang et al. [Computers and Mathematics with Ap-plications 57 (2009) 1232-1248.] and Wang and Watada [Information Sci-ences 179 (2009) 4057-4069.] studied the renewal process and renewal reward process with fuzzy random inter-arrival times and rewards under the T-independence associated with any continuous Archimedean t-norm. But, their main results do not cover the classical theory of the random elementary renewal theorem and random renewal reward theorem when fuzzy random variables degenerate to random variables, and some given assumptions relate to the membership function of the fuzzy variable and the Archimedean t-norm of the results are restrictive. This paper improves the results of Wang and Watada and Wang et al. from a mathematical per-spective. We release some assumptions of the results of Wang and Watada and Wang et al. and completely generalize the classical stochastic renewal theorem and renewal rewards theorem.

• Journal of the Korean Mathematical Society
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• v.56 no.4
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• pp.935-946
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• 2019

Hawkes process is a self-exciting simple point process with clustering effect whose jump rate depends on its entire past history. We consider Hawkes processes with uniform immigrants which is a special case of the Hawkes processes with renewal immigrants. We study the limit theorems for Hawkes processes with uniform immigrants. In particular, we obtain a law of large number, a central limit theorem, and a large deviation principle.

• Journal of the Korean Data and Information Science Society
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• v.15 no.1
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• pp.21-29
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• 2004

In this paper, we define an availability of repairable network system, when the states of links are modeled by alternating renewal processes. The actual availabilities of some well-known network systems are obtained. The expected numbers of failures and repairs of the network systems are also calculated.

• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.51-64
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• 2014

This paper develops a warranty cost model for complex systems with imperfect repair within a warranty period by addressing a practical case that the first inter-failure interval is longer than any other inter-failure intervals. The product is in its best condition before the first failure if repair is imperfect. After the imperfect repair, other inter-failure intervals which are explained by renewal processes, are stochastically smaller than the first inter-failure interval. Based on this idea, we suggest the failure-interval-failure-criterion model. In this model, we consider two random variables, X and Y where X represents failure intervals and Y represents failure criterion. We also obtain the distribution of the number of failures and conduct the warranty cost analysis. We investigate different types of warranty cost models, reliabilities and other measures for various systems including series-parallel configurations. Several numerical examples are discussed to demonstrate the applicability of the methodologies derived in the paper.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.115-121
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• 2013

A number of urban renewal projects are currently being implemented around the world. Current project management tools are limited in effectively dealing with numerous issues regarding management of these projects (e.g., simultaneous execution of multiple projects). As an effort to address this deficiency, an Intelligent Program Management Information System (i-PgMIS) was developed for effective management of urban renewal projects. The i-PgMIS is a web-based system consisting of various modules including cost management, schedule management, risk management, change management, eco-value engineering (EVE) and so on. Based on the recognition of increasing awareness of creating sustainable built environment, this paper focuses on the EVE module that can support eco-value analysis at program-level management. The EVE module is expected to enhance value and sustainability of construction processes throughout the whole 'program' lifecycle and further to support program feasibility study based on life cycle costing.

• Journal of Korean Institute of Industrial Engineers
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• v.8 no.1
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• pp.22-28
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• 1982

Under a continuous-review inventory system, the inventory position process was proved to be asymptotically independent of the general renewal demand processes, when the two processes form an asymptotic unimodel joint distribution. The analytical technique implemented through this work seems to be more like general, and so the periodic-review system can be similarly investigated. In conclusion, the results may be evaluated to direct to the analytical analyses of some inventory systems which have been treated under some restrictions on demand processes.