scispace - formally typeset
Search or ask a question
Topic

Renewal theory

About: Renewal theory is a research topic. Over the lifetime, 2381 publications have been published within this topic receiving 54908 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: This paper focuses on estimating the performance of four numbers of well-mechanized LHD systems with reliability, availability and maintainability (RAM) modeling and throws light on this equipment that need a tailored maintenance schedule, partly due to the peculiar mining conditions, under which they operate.
Abstract: Load haul dumper (LHD) is one of the main ore transporting machineries used in underground mining industry. Reliability of LHD is very significant to achieve the expected targets of production. The performance of the equipment should be maintained at its highest level to fulfill the targets. This can be accomplished only by reducing the sudden breakdowns of component/subsystems in a complex system. The identification of defective component/subsystems can be possible by performing the downtime analysis. Hence, it is very important to develop the proper maintenance strategies for replacement or repair actions of the defective ones. Suitable maintenance management actions improve the performance of the equipment. This paper aims to discuss this issue.,Reliability analysis (renewal approach) has been used to analyze the performance of LHD machine. Allocations of best-fit distribution of data sets were made by the utilization of Kolmogorov–Smirnov (K–S) test. Parametric estimation of theoretical probability distributions was made by utilizing the maximum likelihood estimate (MLE) method.,Independent and identical distribution (IID) assumption of data sets was validated through trend and serial correlation tests. On the basis of test results, the data sets are in accordance with IID assumption. Therefore, renewal process approach has been utilized for further investigation. Allocations of best-fit distribution of data sets were made by the utilization of Kolmogorov–Smirnov (K–S) test. Parametric estimation of theoretical probability distributions was made by utilizing the MLE method. Reliability of each individual subsystem has been computed according to the best-fit distribution. In respect of obtained reliability results, the reliability-based preventive maintenance (PM) time schedules were calculated for the expected 90 percent reliability level.,As the reliability analysis is one of the complex techniques, it requires strategic decision making knowledge for the selection of methodology to be used. As the present case study was from a public sector company, operating under financial constraints the conclusions/findings may not be universally applicable.,The present study throws light on this equipment that need a tailored maintenance schedule, partly due to the peculiar mining conditions, under which they operate. This study mainly focuses on estimating the performance of four numbers of well-mechanized LHD systems with reliability, availability and maintainability (RAM) modeling. Based on the drawn results, reasons for performance drop of each machine were identified. Suitable recommendations were suggested for the enhancement of performance of capital intensive production equipment. As the maintenance management is only the means for performance improvement of the machinery, PM time intervals were estimated with respect to the expected rate of reliability level.

9 citations

Book ChapterDOI
01 Jan 1994
TL;DR: In this article, a simple renewal model is studied which allows for at most one change (AMOC) in the distribution of the underlying interoccurence times, and tests and estimates concerning the change point as well as the magnitude of jump at this point are discussed.
Abstract: A simple renewal model is studied which allows for atmost one change (AMOC) in the distribution of the underlying interoccurence times. We discuss tests and estimates concerning the change point as well as the magnitude of jump at this point. The results include limiting null distributions, consistency of tests and estimates, and asymptotic normality. Proofs make use of invariance principles for the renewal process under consideration.

9 citations

Journal ArticleDOI
TL;DR: In this paper, a renewal model for the aggregate discounted payments and expenses assumed by the insurer is proposed for the medical malpractice insurance, where real interest rates could be stochastic and the dependencies between the expenses, the payments and the delays of payment are examined through the theory of copulas.
Abstract: A renewal model for the aggregate discounted payments and expenses assumed by the insurer is proposed for the “medical malpractice” insurance, where real interest rates could be stochastic and the dependencies between the expenses, the payments and the delays of payment are examined through the theory of copulas. As a first approach to this problem, we present formulas for the first two raw moments and the first joint moment of this aggregate risk process. Examples are given for Erlang claims interoccurence times and delays of payment, Pareto payments and expenses, and the influence of the dependency is illustrated by the Joe copula. Finally the distribution, VaR and TVaR of our risk process are also considered through simulations.

9 citations

Proceedings ArticleDOI
TL;DR: The results indicate that the Epps phenomenon is a product of the finite time decay of lagged correlations of high resolution data, which does not scale with activity.
Abstract: We review the decomposition method of stock return cross-correlations, presented previously for studying the dependence of the correlation coefficient on the resolution of data (Epps effect). Through a toy model of random walk/Brownian motion and memoryless renewal process (i.e. Poisson point process) of observation times we show that in case of analytical treatability, by decomposing the correlations we get the exact result for the frequency dependence. We also demonstrate that our approach produces reasonable fitting of the dependence of correlations on the data resolution in case of empirical data. Our results indicate that the Epps phenomenon is a product of the finite time decay of lagged correlations of high resolution data, which does not scale with activity. The characteristic time is due to a human time scale, the time needed to react to news.

9 citations

Posted Content
TL;DR: It is shown that the TTSHS framework is conveniently suited to capture the time evolution of gene product levels, and unique formulas connecting its mean and variance to underlying model parameters and noise mechanisms are derived.
Abstract: Stochastic dynamics of several systems can be modeled via piecewise deterministic time evolution of the state, interspersed by random discrete events. Within this general class of systems, we consider time-triggered stochastic hybrid systems (TTSHS), where the state evolves continuously according to a linear time-varying dynamical system. Discrete events occur based on an underlying renewal process (timer), and the intervals between successive events follow an arbitrary continuous probability density function. Moreover, whenever the event occurs, the state is reset based on a linear affine transformation that allows for the inclusion of state-dependent and independent noise terms. Our key contribution is derivation of necessary and sufficient conditions for the stability of statistical moments, along with exact analytical expressions for the steady-state moments. These results are illustrated on an example from cell biology, where deterministic synthesis and decay of a gene product (RNA or protein) is coupled to random timing of cell-division events. As experimentally observed, cell-division events occur based on an internal timer that measures the time elapsed since the start of cell cycle (i.e., last event). Upon division, the gene product level is halved, together with a state-dependent noise term that arises due to randomness in the partitioning of molecules between two daughter cells. We show that the TTSHS framework is conveniently suited to capture the time evolution of gene product levels, and derive unique formulas connecting its mean and variance to underlying model parameters and noise mechanisms. Systematic analysis of the formulas reveal counterintuitive insights, such as, if the partitioning noise is large then making the timing of cell division more random reduces noise in gene product levels.

9 citations


Network Information
Related Topics (5)
Markov chain
51.9K papers, 1.3M citations
92% related
Stochastic process
31.2K papers, 898.7K citations
88% related
Probability distribution
40.9K papers, 1.1M citations
84% related
Estimator
97.3K papers, 2.6M citations
81% related
Upper and lower bounds
56.9K papers, 1.1M citations
79% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202327
202260
202173
202083
201973
201886