Abstract:In this article, we survey the developments in the generalised models of repairable systems reliability during 1990s, particularly the last five years. In this field, we notice the sharp fundamental problem that voluminous complex models were developed but there is an absence of sufficient data of interest for justifying the success in tackling the real engineering problems. Instead of following the myth of using simple models to face the complex reality, we select and review some practical models, particularl… Show more
“…Large classes of virtual age models have been presented in [16,22,25]. The ABAO and the AGAN cases correspond to = A T i i and A i ¼0, respectively.…”
Section: Inference With Complete Informationmentioning
confidence: 99%
“…The models used in this section are the imperfect maintenance models presented in Section 5: ARA 1 , ∞ ARA and Brown-Proschan. To compare the performance of different modeling schemes (with and without considering initial age), we propose three approaches, each associated with an estimation method: Approach 1 considers that the initial age is different from zero and uses the likelihood functions developed in previous section: (22) It is worth to notice that the assumption used by Approach 3 is hardly available in practice. It represents however an ideal case of the problem under consideration, and therefore serves as a reference to evaluate the performance of methods 1 and 2.…”
“…Large classes of virtual age models have been presented in [16,22,25]. The ABAO and the AGAN cases correspond to = A T i i and A i ¼0, respectively.…”
Section: Inference With Complete Informationmentioning
confidence: 99%
“…The models used in this section are the imperfect maintenance models presented in Section 5: ARA 1 , ∞ ARA and Brown-Proschan. To compare the performance of different modeling schemes (with and without considering initial age), we propose three approaches, each associated with an estimation method: Approach 1 considers that the initial age is different from zero and uses the likelihood functions developed in previous section: (22) It is worth to notice that the assumption used by Approach 3 is hardly available in practice. It represents however an ideal case of the problem under consideration, and therefore serves as a reference to evaluate the performance of methods 1 and 2.…”
“…The long-run average cost with N cycles is [12] (16) where c m , c p and c r denote the cost of a minimal repair, a PM action and system replacement, respectively.…”
Section: Optimal Values Of Number Of Pm and Long-run Average Costmentioning
confidence: 99%
“…Another important imperfect maintenance model is virtual age model proposed by KIJIMA et al [10−11]. GUO et al [12] generalized this virtual age concept to virtual age process. Based on the failure intensity reduction or virtual age, DOYEN and GAUDOIN [13] studied the classes of imperfect repair models.…”
Based on the log-linear virtual age process, an imperfect preventive maintenance policy for numerical control (NC) machine tools with random maintenance quality is proposed. The proposed model is a combination of the Kijima type virtual age model and the failure intensity adjustment model. Maintenance intervals of the proposed hybrid model are derived when the failure intensity increase factor and the restoration factor are both random variables with uniform distribution. The optimal maintenance policy in infinite time horizon is presented. A numerical example is given when the failures of NC machine tools are described by the log-linear process. Finally, a discussion is presented to show how the optimal results depend on the different cost parameters.
“…[24,25,30]. A literature review, in which delay-time models are investigated along with other PM models are given in [20,21,22,29,32,35,36]. The state of art works, dedicated strictly to DT modelling are given in [1,3,6,7,8,11,12,28,30,33,37].…”
In this paper, the authors' research work is focused on imperfect inspection policy investigation, when not all defects are identified during inspection action performance. They are interested in Block Inspection Policy performance for multi-unit systems, the maintenance policy which is one of the most commonly used in practice. As a result, at the beginning, few words about delay time modelling approach and a brief literature overview is given. Later, the model of Block-Inspection Policy is provided. The numerical example with the use of QNU Octave program is given. In the next Section, the sensitivity analysis of the developed model is characterised. The article ends up with summary and directions for further research. Streszczenie: W artykule autorzy skupili się na analizie nieperfekcyjnej operacji diagnozy stanu systemu, podczas której nie wszystkie symptomy o potencjalnym uszkodzeniu elementów systemu zostają wykryte. Swoimi badaniami autorzy objęli analizę jednej z częściej wykorzystywanych w praktyce polityk obsługiwania Block Inspection Policy (BIP) dla systemów wieloelementowych. W artykule przedstawiono krótki przegląd literatury z badanego obszaru, następnie omówiono koncepcję modelu BIP oraz przedstawiono jego model symulacyjny z wykorzystaniem oprogramowania QNU Octave. W kolejnym punkcie przedstawiono analizę wrażliwości badanego modelu. Pracę kończy podsumowanie i wskazanie kierunków dalszych prac badawczych. Słowa kluczowe: modelowanie relacji czasowych, utrzymanie w stanie zdatności, systemy wieloelementowe
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