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Book part
Publication date: 14 September 2007

Ryuichi Kitamura

Abstract

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Handbook of Transport Modelling
Type: Book
ISBN: 978-0-08-045376-7

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Article
Publication date: 2 October 2020

Neama Temraz

The present paper analyzed a model consisting of one unit with a warm standby unit where the main unit has three states: up, degraded and down.

Abstract

Purpose

The present paper analyzed a model consisting of one unit with a warm standby unit where the main unit has three states: up, degraded and down.

Design/methodology/approach

The semi-Markov model under the regenerative method is used to construct the mathematical model for the system.

Findings

The effectiveness measures of the system are discussed such as availability, reliability, steady-state availability and mean time to system failure. The life and repair times of the system units are assumed to be discrete follow discrete Weibull distribution. Also, the parameters of the discrete Weibull distribution are assumed to be fuzzy with bell-shaped membership function. An application is introduced to show the results obtained for the system and the profit of the presented model.

Originality/value

Rarely papers in literature treated the topic of the discrete-time semi-Markov process using a regenerative point technique.

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Article
Publication date: 1 June 1998

U. Dinesh Kumar and J. Knezevic

High reliability, maintainability, safety and supportability are expected from today’s modern systems. In the recent years supportability has been widely accepted as a…

Abstract

High reliability, maintainability, safety and supportability are expected from today’s modern systems. In the recent years supportability has been widely accepted as a major factor in logistics discipline. The main purpose of this paper is to demonstrate how advanced mathematical models can be used to analyse the effect of supportability on systems availability. The paper discusses supportability aspects and its effect on operational availability of complex systems using advanced mathematical models like Markov, semi‐Markov and non‐Markov models. The powerful mathematical models discussed in the paper would help reliability engineers and practitioners to predict the logistic support requirements to achieve specified operational availability.

Details

International Journal of Quality & Reliability Management, vol. 15 no. 4
Type: Research Article
ISSN: 0265-671X

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Article
Publication date: 7 May 2019

Faqun Qi and Binghai Zhou

The purpose of this paper is to develop novel preventive maintenance (PM) modeling methods for a cold standby system subject to two types of failures: random failure and…

Abstract

Purpose

The purpose of this paper is to develop novel preventive maintenance (PM) modeling methods for a cold standby system subject to two types of failures: random failure and deterioration failure.

Design/methodology/approach

The system consists of two components and a single repair shop, assuming that the repair shop can only service for one component at a time. Based on semi-Markov theory, transition probabilities between all possible system states are discussed. With the transition probabilities, Markov renewal equations are established at regenerative points. By solving the Markov regenerative equations, the mean time from the initial state to system failure (MTSF) and the steady state availability (SSA) are formulated as two reliability measures for different reliability requirements of systems. The optimal PM policies are obtained when MTSF and SSA are maximized.

Findings

The result of simulation experiments verifies that the derived maintenance models are effective. Sensitivity analysis revealed the significant influencing factors for optimal PM policy for cold standby systems when different system reliability indexes (i.e. MTSF and SSA) are considered. Furthermore, the results show that the repair for random failure has a tremendous impact on prolonging the MTSF of cold standby system and PM plays a greater role in promoting the system availability of a cold standby system than it does in prolonging the MTSF of system.

Practical implications

In practical situations, system not only suffers normal deterioration caused by internal factors, but also undergoes random failures influenced by random shocks. Therefore, multiple failure types are needed to be considered in maintenance modeling. The result of the sensitivity analysis has an instructional role in making maintenance decisions by different system reliability indexes (i.e. MTSF and SSA).

Originality/value

This paper presents novel PM modeling methods for a cold standby system subject to two types of failures: random failure and deterioration failure. The sensitivity analysis identifies the significant influencing factors for optimal maintenance policy by different system reliability indexes which are useful for the managers for further decision making.

Details

Journal of Quality in Maintenance Engineering, vol. 25 no. 2
Type: Research Article
ISSN: 1355-2511

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Article
Publication date: 17 August 2015

Alexander Hendrik Maegebier

– Two strands of the literature are combined, namely the modeling of disability insurance and the design, valuation and discussion of insurance-linked securities.

Abstract

Purpose

Two strands of the literature are combined, namely the modeling of disability insurance and the design, valuation and discussion of insurance-linked securities.

Design/methodology/approach

This paper provides a discussion regarding the advantages and detriments of disability-linked securities in comparison with mortality-linked bonds and swaps as well as regarding potential disability-linked indices and the potential use. The discussion is followed by an introduction of a potential design and a corresponding valuation of disability bonds and swaps.

Findings

This securitization will provide useful tools for the risk management of disability risk in a risk-based regulatory framework.

Originality/value

No disability-linked securities have been defined and discussed so far.

Details

The Journal of Risk Finance, vol. 16 no. 4
Type: Research Article
ISSN: 1526-5943

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Article
Publication date: 1 November 1994

M.N. Gopalan and U. Dinesh Kumar

A merge production system which has parallel stations in the first stagefollowed by a single station in the second stage is analysed inconnection with the production rate…

Abstract

A merge production system which has parallel stations in the first stage followed by a single station in the second stage is analysed in connection with the production rate of the system. A mathematical model is developed using semi‐regenerative process and a system of convolution integral equations satisfied by various state probabilities is obtained. An iterative numerical technique is used to solve the system of integral equations obtained to evaluate the production rate of the system.

Details

International Journal of Quality & Reliability Management, vol. 11 no. 8
Type: Research Article
ISSN: 0265-671X

Keywords

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Article
Publication date: 1 December 1997

U. Dinesh Kumar

Derives expressions for performance availability and performance reliability of fault tolerant systems operating under various levels of stress during a mission using…

Abstract

Derives expressions for performance availability and performance reliability of fault tolerant systems operating under various levels of stress during a mission using stochastic reward models (SRM). Develops a mathematical model using semi‐regenerative reward model. Obtains a system of convolution integral equations satisfied by various state probabilities corresponding to different initial conditions. As a particular case, analyses a 3‐unit parallel system under three different stress levels. Uses an iterative numerical method to solve the system of integral equations satisfied by various state probabilities to study the effect of parameters on various system performance.

Details

International Journal of Quality & Reliability Management, vol. 14 no. 9
Type: Research Article
ISSN: 0265-671X

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Article
Publication date: 19 April 2011

S. Samar Ali and S. Kannan

The objective of the paper is to consider the problem of the strength of a manufactured item against stress, when the component follows Weibull failure law. Different…

Abstract

Purpose

The objective of the paper is to consider the problem of the strength of a manufactured item against stress, when the component follows Weibull failure law. Different cases of stress and strength with varying parameters are discussed for the Weibull‐Weibull stress‐strength model considered in this paper. The application of the proposed technique will help in understanding the design methodology of the system and addressing the risks involved in perceived quality and reliability levels by eliminating or at least reducing the risk impact at the design phase.

Design/methodology/approach

Generalised Weibull‐Weibull stress‐strength models have been analysed for different cases of shape parameters for stress and strength to estimate the reliability of the system. The model is generalized using semi‐regenerative stochastic processes with the help of a state space approach to include a repair facility.

Findings

Different cases of stress and strength with varying parameters have been discussed for the Weibull‐Weibull stress‐strength models considered in this paper. The results show how the stress‐strength reliability model is affected by changes in the parameters of stress and strength. The application of the proposed technique will help in understanding the design methodology of the system, and also lead to the problem of addressing the risks involved in perceived quality and reliability levels by eliminating or at least reducing the risk impact in the design phase.

Research limitations/implications

The present study is limited to a few special cases of Weibull‐Weibull stress‐strength models. The authors propose to continue to study the behaviour of general Weibull strength against exponential stress in particular and to identify the shape parameter that maximises the strength reliability.

Practical implications

The application of the proposed technique will help in understanding the design methodology of the system, and also lead to the problem of addressing the risks involved in perceived quality and reliability levels by eliminating or at least reducing the risk impact at the design phase. The model has been extended and generalized to include a repair facility under the assumption that all the random variables involved in the analysis are arbitrarily distributed (i.e. general).

Originality/value

In the Weibull‐Weibull stress‐strength model of reliability, different cases have been considered. In the first case, both parameters of stress‐strength have the same values and are independent of the distribution. In the second case, if the shape parameter of the strength is twice that of the stress, the probability will have a normal distribution with different parameter values. In the third case, if the shape parameter of the stress is twice that of the strength, then probability distribution is a parabolic cylindrical function. The study shows how to proceed in all cases. The model is generalized to include a repair facility, with all the random variables involved in the analysis being arbitrarily distributed using semi‐regenerative stochastic processes.

Details

International Journal of Quality & Reliability Management, vol. 28 no. 4
Type: Research Article
ISSN: 0265-671X

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Article
Publication date: 1 December 2000

V. Sridharan

Presents two models. Model I deals with some characteristics of a single unit system with a sensing device and two types of repairmen. The unit is attached to a sensing…

Abstract

Presents two models. Model I deals with some characteristics of a single unit system with a sensing device and two types of repairmen. The unit is attached to a sensing device which completely monitors the operating or non‐operating status of the unit. The regular repairman is always available with the system and inspects the operation of the sensing device. If the device is not working, then an expert repairman is called to the system and the operational status of the unit is now monitored by the expert repairman. It is assumed that the failure of the unit, repair of the regular, expert and the status of the sensing device are stochastically independent random variables each having an arbitrary distribution. Several important results have been derived including profit with some applications. In model II, a two‐unit cold standby system with pre‐inspection is considered. In this model, first the regular repairman inspects every unit that fails to ascertain whether he is able to repair it or not. If he can repair it, he proceeds; otherwise an expert repairman is called. An analytical approach to find the optimum interchanging time of units by giving rest to the operative unit is obtained.

Details

International Journal of Quality & Reliability Management, vol. 17 no. 9
Type: Research Article
ISSN: 0265-671X

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Article
Publication date: 1 August 1994

M.N. Gopalan and S. Kannan

Incorporates the concept of quality control in the probabilisticanalysis of two‐stage production systems. Provides an integratedframework to consider manufacturing…

Abstract

Incorporates the concept of quality control in the probabilistic analysis of two‐stage production systems. Provides an integrated framework to consider manufacturing, inspection and rework activities simultaneously. The system is provided with an initial storage of unlimited capacity. Rework of a defective item produced by machine I is done on machine I itself and depends on the type of defect. Explicit expressions for some of the system characteristics have been obtained using the state‐space method and regeneration point technique. All the random variables involved in the analysis are assumed to be arbitrarily distributed (i.e. general).

Details

International Journal of Quality & Reliability Management, vol. 11 no. 6
Type: Research Article
ISSN: 0265-671X

Keywords

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