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Article
Publication date: 2 January 2018

Sarada Yedida and Shenbagam R.

Technological advancements and growing complexity of many real-time systems, namely, communication, transportation, defense systems, etc., necessitate the importance to adopt a…

Abstract

Purpose

Technological advancements and growing complexity of many real-time systems, namely, communication, transportation, defense systems, etc., necessitate the importance to adopt a well-planned repair process such as phase type quasi-renewal process contributing to an improved system performance. Further, in an attempt to boost the role of maintenance as a financial benefactor, repairman’s multiple vacation policy is incorporated. Also, the significance of the degree of repair is illustrated while indicating the suitability of the matrix-analytic approach via the phase type quasi-renewal operating/repair times in reliability. The paper aims to discuss these issues.

Design/methodology/approach

The optimal replacement policy is obtained by employing the matrix-analytic method and minimum average cost rate.

Findings

The considered models make a significant contribution towards establishing that the matrix-analytic method, using the phase type quasi-renewal process, aids in reducing the computations and also fills the gap in the literature in the study of deteriorating systems. Availability and rate of occurrence of failures are evaluated in transient and steady-state regime.

Originality/value

This model differs from the existing models, in that, a repairman’s multiple vacation, delayed repair time and representation of the failure occurrence by a mixed Poisson process have been incorporated into the analysis. Also, time-dependent case and N-policy have been adopted to explore the optimality issues using phase type quasi-renewal process analytically. The numerical illustrations warrant that the maintenance policy proposed in this paper produces a considerably lower cost.

Details

International Journal of Quality & Reliability Management, vol. 35 no. 1
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 30 July 2021

  Supriyono, Tzu-Chia Chen, Lis M. Yapanto, Zagir Azgarovich Latipov, Angelina Olegovna Zekiy, Lyubov A. Melnikova, Lakshmi Thangavelu, A. Surendar, Nikolay I. Repnikov and Zeinab Arzehgar

In this paper, a lifetime estimation model for the solder joint is proposed which is capable of considering both severe and running mechanical shocks which is the real case in…

Abstract

Purpose

In this paper, a lifetime estimation model for the solder joint is proposed which is capable of considering both severe and running mechanical shocks which is the real case in electric converters in the automotive and aerospace applications. This paper aims to asses the reliability of the solder joint under mixed exposure of mechanical loads.

Design/methodology/approach

Mechanical failure process may put at risk the perfect performance of any kinds of electronic systems regardless of the applications they are prepared for. Observation of solder joint health in an electronic assembly under simultaneous exposure of severe and running shocks is an open problem. Three commonly used soldering compositions are considered while the electronic assembly is exposed to three well-known driving cycles.

Findings

The results show that the best performance is achieved using SAC405 soldering alloy in comparison with Sn63Pb37 and SAC387 solder alloy. Consideration of mixed exposure to the mechanical loads leads to much more accurate lifetime estimation of the solder joint in the electronic assemblies.

Originality/value

The originality of the paper is confirmed.

Details

Soldering & Surface Mount Technology, vol. 34 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 6 March 2007

Jiandong Ren

The purpose of this article is to consider the classical risk model that is perturbed by a Brownian motion process. The article derives explicit formulas for the joint and…

Abstract

Purpose

The purpose of this article is to consider the classical risk model that is perturbed by a Brownian motion process. The article derives explicit formulas for the joint and marginal probability density functions of the surplus prior to ruin and the deficit at ruin.

Design/methodology/approach

This article first extends the dual argument to probabilistically explain the symmetry between the two random variables related to the so‐called modified ladder height. Then the paper uses renewal arguments to derive the joint distribution of the surplus prior to ruin and the deficit at ruin.

Findings

The study derived an explicit formula for the undiscounted joint density in the perturbed risk model that is directly parallel to formula (3.2) for the classical risk model. The formula clearly shows that in a perturbed risk process, when ruin is caused by a claim, the p.d.f. of the surplus prior to ruin is continuous. In addition, shows that when the claim sizes follow a phase‐type distribution, all the relevant quantities can be conveniently computed.

Originality/value

The dual argument used in this article is novel. The formula first clearly shows that in the perturbed risk model, the p.d.f. of the surplus prior to ruin is continuous. When claim sizes are phase‐type, the formulas can be conveniently computed.

Details

The Journal of Risk Finance, vol. 8 no. 2
Type: Research Article
ISSN: 1526-5943

Keywords

Article
Publication date: 8 January 2018

Wenyan Zhuo, Honglin Yang and Xu Chen

The purpose of this paper is to build a phase-type risk model with stochastic return on investment and random observation periods to characterize the ruin quantities under which…

Abstract

Purpose

The purpose of this paper is to build a phase-type risk model with stochastic return on investment and random observation periods to characterize the ruin quantities under which the insurance company may take effective investment strategies to avoid bankruptcy.

Design/methodology/approach

By the Markov property and Ito’s formula, this paper derives the integro-differential equations in which the interclaim times follow a phase-type distribution. Using the sinc method, this paper obtains the approximate solutions of the expected discounted penalty function. The numerical examples are given to verify the robustness of the proposed sinc method.

Findings

This paper discloses the relationship between the investment strategy and initial surplus level. The insurance company with a high initial surplus level prefers high risk portfolios to earn more profit. Contrarily, the insurance company would invest low risk portfolios to avoid bankruptcy. In addition, this paper shows that a short observation period would bring higher ruin probability.

Originality/value

The risk model is distinct in that a phase-type risk model is constructed with stochastic return on investment and random observation periods. These considerations in the risk model are in sharp contrast to the setting in which the stochastic return on investment is observed continuously. In practice, the insurance company only can periodically observe the surplus level to check the balance of the book. This setting, therefore, is difficult to adopt. This paper develops a sinc method to solve the approximate solutions of the expected discounted penalty function.

Article
Publication date: 5 March 2021

Mohammad Reza Pourhassan, Sadigh Raissi and Arash Apornak

In some environments, the failure rate of a system depends not only on time but also on the system condition, such as vibrational level, efficiency and the number of random…

Abstract

Purpose

In some environments, the failure rate of a system depends not only on time but also on the system condition, such as vibrational level, efficiency and the number of random shocks, each of which causes failure. In this situation, systems can keep working, though they fail gradually. So, the purpose of this paper is modeling multi-state system reliability analysis in capacitor bank under fatal and nonfatal shocks by a simulation approach.

Design/methodology/approach

In some situations, there may be several levels of failure where the system performance diminishes gradually. However, if the level of failure is beyond a certain threshold, the system may stop working. Transition from one faulty stage to the next can lead the system to more rapid degradation. Thus, in failure analysis, the authors need to consider the transition rate from these stages in order to model the failure process.

Findings

This study aims to perform multi-state system reliability analysis in energy storage facilities of SAIPA Corporation. This is performed to extract a predictive model for failure behavior as well as to analyze the effect of shocks on deterioration. The results indicate that the reliability of the system improved by 6%.

Originality/value

The results of this study can provide more confidence for critical system designers who are engaged on the proper system performance beyond economic design.

Details

International Journal of Quality & Reliability Management, vol. 38 no. 10
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 6 June 2016

S. Mohammad Hashemian, Rassoul Noorossana, Ali Keyvandarian and Maryam Shekary A.

The purpose of this paper is to compare the performances of np-VP control chart with estimated parameter to the np-VP control chart with known parameter using average…

Abstract

Purpose

The purpose of this paper is to compare the performances of np-VP control chart with estimated parameter to the np-VP control chart with known parameter using average time-to-signal (ATS), standard deviation of the time-to-signal (SDTS), and average number of observations to signal (ANOS) as performance measures.

Design/methodology/approach

The approach used in this study is probabilistic in which the expected values of performance measures are calculated using probabilities of different estimators used to estimate process parameter.

Findings

Numerical results indicate different performances for the np-VP control chart in known and estimated parameter cases. It is obvious that when process parameter is not known and is estimated using Phase I data, the chart does not perform as user expects. To tackle this issue, optimal Phase I estimation scenarios are recommended to obtain the best performance from the chart in the parameter estimation case in terms of performance measures.

Practical implications

This research adds to the body of knowledge in quality control of process monitoring systems. This paper may be of particular interest to practitioners of quality systems in factories where products are monitored to reduce the number of defectives and np chart parameter needs to be estimated.

Originality/value

The originality of this paper lies within the context in which an adaptive np control chart is studied and the process parameter unlike previous studies is assumed unknown. Although other types of control charts have been studied when process parameter is unknown but this is the first time that adaptive np chart performance with estimated process parameter is studied.

Details

International Journal of Quality & Reliability Management, vol. 33 no. 6
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 20 July 2012

Biman Das, Alberto Garcia‐Diaz, Corinne A. MacDonald and Kalyan K. Ghoshal

The purpose of this paper is to develop a computer simulation model to evaluate increasing versus decreasing mean operation times assembly line arrangement for normal and…

Abstract

Purpose

The purpose of this paper is to develop a computer simulation model to evaluate increasing versus decreasing mean operation times assembly line arrangement for normal and exponential distributions and the variances equal to 1 and 16.

Design/methodology/approach

The model was developed on the basis of a realistic case problem and applied to a six‐station assembly line. The evaluation criteria were: the minimization of the total elapsed time; the maximization of the average percentage of working time; and the minimization of the average time in the system.

Findings

The increasing mean operation times line arrangement is superior to the decreasing mean operation times line arrangement for the normal and exponential distributions and the variances equal to 1 and 16, in terms of the total elapsed time and the average percentage of the working time evaluation criteria. The decreasing mean operation times lines is marginally superior to the increasing operation times line for the normal distribution for the variances equal to 1 and 16, in terms of the average time in the system evaluation criterion. The above inference can be made for the exponential distribution for the variance 16, but no definitive conclusion can be made for the variance 1. Overall, the increasing mean operation times line arrangement has proven to be superior to the decreasing operation times line arrangement for both the stated distributions and variances, in terms of the important evaluation criteria.

Originality/value

The paper contributes to the computer simulation approach to solving assembly line problems that deal with the impact of normally and exponentially distributed operation times, with variances equal to 1 and 16, on the increasing and decreasing mean operation times assembly line arrangements.

Details

Journal of Manufacturing Technology Management, vol. 23 no. 6
Type: Research Article
ISSN: 1741-038X

Keywords

Article
Publication date: 9 March 2015

Christophe Letot, Pierre Dehombreux, Edouard Rivière-Lorphèvre, Guillaume Fleurquin and Arnaud Lesage

The purpose of this paper is to highlight the need for degradation data in order to improve the reliability and the mean residual life estimation of a specific item of equipment…

Abstract

Purpose

The purpose of this paper is to highlight the need for degradation data in order to improve the reliability and the mean residual life estimation of a specific item of equipment and to adapt the preventive maintenance tasks accordingly.

Design/methodology/approach

An initial reliability model which uses a degradation-based reliability model that is built from the collection of hitting times of a failure threshold. The proposed maintenance model is based on the cost/availability criterion. The estimation of both reliability and optimum time for preventive maintenance are updated with all new degradation data that are collected during operating time.

Findings

An improvement for the occurrences of maintenance tasks which minimizes the mean cost per unit of time and increases the availability.

Practical implications

Inspection tasks to measure the degradation level should be realized at least one time for each item of equipment at a specific time determined by the proposed methodology.

Originality/value

The introduction of a criterion which helps the maintainer to decide to postpone or not the preventive replacement time depending on the measured degradation level of a specific item of equipment.

Details

Journal of Quality in Maintenance Engineering, vol. 21 no. 1
Type: Research Article
ISSN: 1355-2511

Keywords

Article
Publication date: 5 May 2015

Srinivasa Rao M. and V.N.A Naikan

The purpose of this paper is to propose a novel hybrid approach called as Markov System Dynamics (MSD) approach which combines the Markov approach with system dynamics (SD…

1627

Abstract

Purpose

The purpose of this paper is to propose a novel hybrid approach called as Markov System Dynamics (MSD) approach which combines the Markov approach with system dynamics (SD) simulation approach for availability modeling and to study the dynamic behavior of repairable systems.

Design/methodology/approach

In the proposed approach the identification of the single unit repairable system all possible states has been performed by using the Markov approach. The remaining stages of traditional Markov analysis are highly mathematically intensive. The present work proposes a hybrid approach called as MSD approach which combines the Markov approach with SD simulation approach to overcome some of the limitations of Markov process in a simple and efficient way for availability modeling and to study the dynamic behavior of this system.

Findings

The proposed framework is illustrated for a single unit repairable system. The worked out example shows the steady state point and also it gives the point, interval and steady state availabilities and also the dynamic behavior of the system. However this methodology can be extended easily for more complex multi-state maintainable systems. The results of the simulation when compared with that obtained by traditional Markov analysis clearly validate the proposed approach as an alternative approach for availability modeling of repairable systems.

Practical implications

In many practical situations we require to find the time at which our system reaches steady state conditions for planning maintenance activities. The proposed MSD method in this paper is capable of finding this steady state point very easily.

Originality/value

The proposed approach clearly indicates the time at which the system reaches its steady state and calculates the point, interval availabilities for planning maintenance activities. The different parties, i.e., engineers and machine operators, can jointly work with this model in order to understand the dynamic behavior of repairable systems.

Details

International Journal of Quality & Reliability Management, vol. 32 no. 5
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 25 October 2011

Abdelhakim Khatab, Nidhal Rezg and Daoud Ait‐Kadi

This paper aims to investigate the optimization of the replacement with minimal repair policy for a system which experiences a time horizon of random length. Under such policy…

Abstract

Purpose

This paper aims to investigate the optimization of the replacement with minimal repair policy for a system which experiences a time horizon of random length. Under such policy system replacement occurs at multiples of some period while minimal repair is performed at system failure between two successive replacements.

Design/methodology/approach

The objective function is the expected total cost composed of minimal repairs and replacements costs. A simple and compact expression is derived for the expected total costs and conditions under which an optimal replacement period exits are given. For sake of illustration, a numerical example is provided.

Findings

The paper finds that by the recent great technological development, the life cycle of present products is seen to be reduced more and more. This has motivated the development of maintenance optimization models for systems which experience an exact finite time horizon.

Originality/value

To ensure the benefits from the improved technologies, the information concerning the technological change must be taken into account. Such information is based on technological forecasting and difficult to obtain and merely rely on uncertainties.

Details

Journal of Quality in Maintenance Engineering, vol. 17 no. 4
Type: Research Article
ISSN: 1355-2511

Keywords

1 – 10 of 62