• 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.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.3
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• pp.219-223
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• 2009

Recently, Zhao et al. [Fuzzy Optimization and Decision Making (2007) 6, 279-295] characterized the interarrival times as fuzzy random variables and presented a fuzzy random elementary renewal theorem on the limit value of the expected renewal rate of the process in the fuzzy random renewal process. They also depicted both the interarrival times and rewards are depicted as fuzzy random variables and provided fuzzy random renewal reward theorem on the limit value of the long run expected reward per unit time in the fuzzy random renewal reward process. In this note, we simplify the proofs of two main results of the paper.

• Environmental Engineering Research
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• v.24 no.1
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• pp.63-73
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• 2019

This study suggests a method for calculating the benefits of water pipe renewal based on an estimate of the water supply suspension risk. The proposed method based on five benefit items is more direct and specific than other benefit estimation methods. In addition, a methodology evaluating the economics of pipe renewal based on pipe failure rate is proposed for estimating the optimal renewal point from an economic perspective. By estimating the optimal renewal period based on a yearly benefit cost ratio per pipe in a case study area, it was possible to draft an optimal renewal plan for the subject region from an economic perspective. Compared with other methodologies, a reasonable optimal renewal period was derived from an economic point of view. The result of this study may be used to develop future water pipe renewal plans. Moreover, the proposed methodologies and results derived from this study can be applied to asset management plans.

• The Korean Journal of Applied Statistics
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• v.20 no.2
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• pp.333-343
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• 2007

The auxiliary renewal function has an important role in analyzng queues in which the either of the inter-arrival time and the service time of customers is not exponential. As like the renewal function, the auxiliary renewal function is hard to compute although it can be defined theoretically. In this paper, we suggest two approximations for auxiliary renewal function and compare the two with the true value of auxiliary renewal function which can be computed in some special cases.

• Korean Institute of Interior Design Journal
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• v.23 no.6
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• pp.60-69
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• 2014

The features of the cultural phenomenon, 'Hybrid Culture,' can be analyzed through the concept of 'Meme,' the cultural gene continuously evolves. The architectural meme also has an effect as the cultural symbol on a space. It can be the solution to the urban problems, lack of contextualization caused by reckless development. Therefore, this study aims to examine the characteristics of the sustainable and effective renewal space by applying the concept of Meme. Theoretical analysis, characteristics of expression, and case study are conducted to analyze the Meme features of the renewal space. Particularly, this study focuses on the Meme features appeared in the Zollverein Coal Mine Industrial Complex in German. The results obtained from this study is as written below. First, Meme renewal space is a design that can solve the contextual deficiency of architecture through the cultural renewal. Second, the true renewal space has the characteristics of meme space that organically changes as if an organism. Third, it is possible to conduct a detailed analysis on the organic characteristics according to the evolving phases-Mimesis, Memeplex, and Metameme. Fourth, the true meaning of sustainable renewal space is the Meme space encompasses the scope of urban. Lastly, the Meme space has a circulation system that each evolving phase, and new and old continuously exchange feedbacks.

• 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.

• International Journal of Reliability and Applications
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• v.1 no.1
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• pp.81-87
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• 2000

One of the most important quantities in reliability theory is the expected number of renewals of a system during a given interval. This quantity, the renewal function, is used to determine the optimal preventive maintenance policy and to estimate the cost of a warranty. In this paper we study a parametric approach for a renewal function. The simulation study is presented to compare the relative performance of the introduced estimators of a renewal function. And we show that the proposed parametric estimator performs well.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1459-1463
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• 2009

Recently, Zhao et.al [European Journal of Operational Research 169 (2006) 189-201] discussed a random fuzzy renewal process based on random fuzzy theory. They considered the rate of the random fuzzy renewal process and presented a random fuzzy elementary renewal theorem. They also established Blackwell's theorem in random fuzzy sense. But all these results are invalid. We give a counter example in this note.

• 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 the Korean housing association
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• v.27 no.1
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• pp.51-61
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• 2016

Under the guise of a residential environment improvement, distendedly designated Pre-Housing Renewal districts and Renewal Districts by Basic Plan for Renewal Projects are not promoted and leaved for a long-term so that residential problems have become worse. In case of the canceled Housing Renewal district, at the time when the district are canceled, the residential environment has become already superannuated for more than 10 years but there is no follow-up plan to manage that problem so that the exact management plan for those neglected districts is urgently needed. Therefore, the purpose of this study is to analyze the aspect of change of residential environment after the cancellation and indicate appearing problems by conducting on the case of Canceled districts of Daegu Housing Renewal District. This study will be the first step to seek practical management measures for canceled districts, and on the basis of this, the research will become a precedent to seek the sustainable planning measures for the designation and management of Renewal Projects from now on.