Multi-state failure phenomenon and analysis using semi-Markov model

2018 ◽  
Vol 35 (9) ◽  
pp. 2080-2091 ◽  
Author(s):  
Mahesh Narayan Dhawalikar ◽  
V. Mariappan ◽  
P.K. Srividhya ◽  
Vishal Kurtikar
Keyword(s):  
Markov Model ◽  
Weibull Distribution ◽  
Exponential Distribution ◽  
Failure Rate ◽  
Degradation Process ◽  
Markov Modeling ◽  
Content Type ◽  
Availability Analysis ◽  
Unique Approach ◽  
Reliability And Availability

Purpose Degraded failures and sudden critical failures are quite prevalent in industries. Degradation processes commonly belong to Weibull family and critical failures are found to follow exponential distribution. Therefore, it becomes important to carry out reliability and availability analysis of such systems. From the reported literature, it is learnt that models are available for the situations where the degraded failures as well as critical failures follow exponential distribution. The purpose of this paper is to present models suitable for reliability and availability analysis of systems where the degradation process follows Weibull distribution and critical failures follow exponential distribution. Design/methodology/approach The research uses Semi-Markov modeling using the approach of method of stages which is suitable when the failure processes follow Weibull distribution. The paper considers various states of the system and uses state transition diagram to present the transition of the system among good state, degraded state and failed state. Method of stages is used to convert the semi-Markov model to Markov model. The number of stages calculated in Method of stages is usually not an integer value which needs to be round off. Method of stages thus suffers from the rounding off error. A unique approach is proposed to arrive at failure rates to reduce the error in method of stages. Periodic inspection and repairs of systems are commonly followed in industries to take care of system degradation. This paper presents models to carry out reliability and availability analysis of the systems including the case where degraded failures can be arrested by appropriate inspection and repair. Findings The proposed method for estimating the degraded failure rate can be used to reduce the error in method of stages. The models and the methodology are suitable for reliability and availability analysis of systems involving degradation which is very common in systems involving moving parts. These models are very suitable in accurately estimating the system reliability and availability which is very important in industry. The models conveniently cover the cases of degraded systems for which the model proposed by Hokstad and Frovig is not suitable. Research limitations/implications The models developed consider the systems where the repair phenomenon follows exponential and the failure mechanism follows Weibull with shape parameter greater than 1. Practical implications These models can be suitably used to deal with reliability and availability analysis of systems where the degradation process is non-exponential. Thus, the models can be practically used to meet the industrial requirement of accurately estimating the reliability and availability of degradable systems. Originality/value A unique approach is presented in this paper for estimating degraded failure rate in the method of stages which reduces the rounding error. The models presented for reliability and availability analyses can deal with degradable systems where the degradation process follows Weibull distribution, which is not possible with the model presented by Hokstad and Frovig.

Availability analysis of a LNG processing plant using the Markov process

2016 ◽  
Vol 22 (3) ◽  
pp. 302-320 ◽  
Author(s):  
Jakiul Hassan ◽  
Premkumar Thodi ◽  
Faisal Khan
Keyword(s):  
Markov Process ◽  
System Performance ◽  
Major Influence ◽  
Processing Plant ◽  
Alternative Mechanism ◽  
Markov Modeling ◽  
Markov Analysis ◽  
Content Type ◽  
Availability Analysis ◽  
State Dependent

Purpose – The purpose of this paper is to propose a state dependent stochastic Markov model for availability analysis of process plant instead of traditional time dependent model. Design/methodology/approach – The traditional concepts of system performance measurement and reliability (namely, binary; two-state concepts) are observed to be inadequate to characterize performance of complex system components. Availability analysis considering an intermediate state, such as a degraded state, provides a better alternative mechanism for system performance mapping. The availability model provides a better assessment of failure and repair characteristics for equipment in the sub-system and its overall performance. In addition to availability analysis, this paper also discusses the preventive maintenance (PM) program to achieve target availability. In this model, the degraded state is considered as a PM state. Using Markov analysis the optimum maintenance interval is determined. Findings – Markov process provides an easier way to measure the performance of the process facility. This study also revealed that the maintenance interval has a major influence in the availability of a process facility as well as in maintaining target availability. The developed model is also applicable to the varying target availability as well as having the capability to handle even the reconfigured process systems. Research limitations/implications – Considering the degraded state as an operative state, a higher availability of the plant is predicted. The consideration of the degraded state of the system makes the availability estimation more realistic and acceptable. Availability quantification, target availability allocation and a PM model are exemplified in a sub-system of an liquefied natural gas facility. Originality/value – The unique features of the present study are; Markov modeling approach integrating availability and PM; optimum PM interval determination of stochastically degrading components based on target availability; consideration of three-state systems; and consideration of increasing failure rates.

Research on an exponential distribution reliability function model based on multi-source heterogeneous data supplements

2017 ◽  
Vol 7 (3) ◽  
pp. 329-342 ◽  
Author(s):  
Heng Shao ◽  
Zhigeng Fang ◽  
Qin Zhang ◽  
Qian Hu ◽  
Jiajia Cai ◽  
...  
Keyword(s):  
Exponential Distribution ◽  
Failure Rate ◽  
Information Acquisition ◽  
Programming Model ◽  
Reliability Function ◽  
Heterogeneous Data ◽  
Rate Data ◽  
Unified Framework ◽  
Content Type ◽  
Multi Objective Programming

Purpose As productions show characteristics of multi-varieties and small batch in a recent new product system, it is more difficult to acquire its failure rate data. With the help of expert experience information, the authors can get the interval estimation of failure rate data under different methods, so how to make the interval convergence with the new information is an important problem to be solved. The paper aims to discuss this issue. Design/methodology/approach In this paper, the concept of generalized standard grey number is used to characterize the multi-source heterogeneous uncertainty failure rate data into a unified framework. Then, the engineering construction method is used to calculate the average failure rate and build the grey exponential distribution reliability function, whose image is presented as the possible region of the two-curve envelope. Findings Further, according to the normal distribution assumption of the regional convergence based on the information supplement, the convergence problem of the reliability function is transformed into the convergence of the area of the curve envelope region, and construct the multi-objective programming model with the minimum envelope area and the lowest total cost of information acquisition, acquire the conclusion that the failure rate is equal to the nuclear of the average failure rate when the envelope region converges. Originality/value Through the case analysis of the equipment ejection system of the Harbinger system, five groups of results are obtained by Matlab simulation, which verify the rationality and feasibility of the model described in this paper.

Analysis of discrete-time semi-Markov model for a two-unit warm standby system subject to degradation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Neama Temraz
Keyword(s):  
Markov Model ◽  
Weibull Distribution ◽  
Discrete Time ◽  
Content Type ◽  
Regenerative Point ◽  
Semi Markov Process ◽  
Regenerative Point Technique ◽  
The Mathematical Model ◽  
Mean Time ◽  
Warm Standby

PurposeThe 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/approachThe semi-Markov model under the regenerative method is used to construct the mathematical model for the system.FindingsThe 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/valueRarely papers in literature treated the topic of the discrete-time semi-Markov process using a regenerative point technique.

Application of the mixed Weibull distribution in machine reliability analysis for a cell formation problem

2017 ◽  
Vol 34 (1) ◽  
pp. 128-142 ◽  
Author(s):  
Reza Ghavijorbozeh ◽  
Ali Zeinal Hamadani
Keyword(s):  
Weibull Distribution ◽  
Reliability Analysis ◽  
Failure Rate ◽  
Cell Formation ◽  
Past Research ◽  
Cell Formation Problem ◽  
Content Type ◽  
Model Based ◽  
Formation Problem ◽  
Mixed Distribution

Purpose The purpose of this paper is to understand the consequence of the use of mixed Weibull distribution in the cell formation problem. In reliability theory, a mixed distribution is used for more than one hazard cause, and the Weibull distribution can be used for ascendant, monotonous and descendant failure rate. Here, the authors mixed these two theme and use it in a common problem in group technology. Design/methodology/approach In this paper, the authors made a non-polynomial-hard mathematical model based on past research and solved it with an exact algorithm. The algorithm is coded and solved in GAMS to illustrate the model, and the authors use simulation. A common numerical example is solved with the model, and the results are compared. Findings Reliability analysis model based on the mixed Weibull distribution approach will give options to a user to select the suitable failure rate and modes for a specific situation. If the user uses the exponential or Weibull distribution instead of the mixed Weibull distribution, the calculated cost and reliability are wrong; therefore, it leads to user making wrong decisions. Originality/value The model the authors use is the one used in past research, but in the past, researchers did not use the mixed distribution for explaining failure time. Therefore, the model can be considered as a new and more complete model.

scholarly journals Inference for the Exponential Distribution under Generalized Progressively Hybrid Censored Data from Partially Accelerated Life Tests with a Time Transformation Function

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1510
Author(s):  
Alaa H. Abdel-Hamid ◽  
Atef F. Hashem
Keyword(s):  
Exponential Distribution ◽  
Failure Rate ◽  
Censored Data ◽  
Sufficient Conditions ◽  
Transformation Function ◽  
Point Estimation ◽  
Estimation Methods ◽  
Time Transformation ◽  
Monte Carlo Simulation Study ◽  
Accelerated Life

In this article, the tampered failure rate model is used in partially accelerated life testing. A non-decreasing time function, often called a ‘‘time transformation function", is proposed to tamper the failure rate under design conditions. Different types of the proposed function, which have sufficient conditions in order to be accelerating functions, are investigated. A baseline failure rate of the exponential distribution is considered. Some point estimation methods, as well as approximate confidence intervals, for the parameters involved are discussed based on generalized progressively hybrid censored data. The determination of the optimal stress change time is discussed under two different criteria of optimality. A real dataset is employed to explain the theoretical outcomes discussed in this article. Finally, a Monte Carlo simulation study is carried out to examine the performance of the estimation methods and the optimality criteria.

Problem-posing in management classrooms for collective sustainability transformation

2021 ◽  
Vol 22 (3) ◽  
pp. 477-496
Author(s):  
Janette Brunstein ◽  
Mark Edward Walvoord ◽  
Ed Cunliff
Keyword(s):  
Transformative Learning ◽  
Learning Objectives ◽  
Problem Posing ◽  
Content Type ◽  
Analysis Methodology ◽  
Unique Approach ◽  
Teaching Cases ◽  
Classroom Use

Purpose The purpose of this study is to examine the possible benefits of approaching sustainability-related teaching cases from the perspective of problem-posing (PP) instead of problem-solving (PS). Design/methodology/approach A document analysis methodology (Silverman, 2011) was used to analyze sustainability teaching case study abstracts and learning objectives from business databases. Cases were reviewed and classified as PP, PS or other. PP cases were further subclassified on one of three axes. Findings Of 117 cases reviewed, most were PS (66%) with only 9% PP. Theoretical and pedagogical implications are discussed with recommendations for writing or converting, PS to PP cases for classroom use. Theoretical contributions include identification of three distinct and complementary views of PP, described in these axes: emancipatory; problematizing metaphors and premises; and rational, process and means-focused cases, not triggering transformative learning theory. Of 10 cases classified as PP cases, 3 were subclassified as emancipatory. Research limitations/implications This research is limited to case study titles containing “sustainability” and analyses of their descriptions and learning objectives only. Next phases of the research will examine differences in student learning between PS and PP in situ. Practical implications The research identifies a unique approach to the authoring and use of case studies that hold the potential for increasing students’ critical thinking capabilities and production of solutions to sustainability issues. Originality/value There is limited research and analysis of the identification and implications of using PP pedagogy.

Preservation for diverse users: digital preservation and the “Designated Community” at the Ontario Jewish Archives

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nathan Moles
Keyword(s):  
Digital Preservation ◽  
Reference Points ◽  
Digital Information ◽  
User Group ◽  
Content Type ◽  
Open Archival Information System ◽  
Novel Approach ◽  
Core Components ◽  
Unique Approach

PurposeConventional approaches to digital preservation posit that archives should define a Designated Community, or future user group, for whom they preserve digital information. Archivists can then use their knowledge of these users as a reference to help them deliver digital information that is intelligible and usable. However, this approach is challenging for archives with mandates to serve wide and diverse audiences; these archives risk undermining their efforts by focusing on the interests of a narrow user group.Design/methodology/approachA unique approach to this challenge was developed in the context of a project to build a digital preservation program at the Ontario Jewish Archives (OJA). It draws from previous research on this topic and is based on a combination of practical and theoretical considerations.FindingsThe approach described here replaces the reference of a Designated Community with three core components: a re-articulation of the Open Archival Information System (OAIS) mandatory responsibilities; the identification of three distinct tiers of access for digital records; and the implementation of an access portal that allows digital records to be accessed and rendered online. Together with supplemental shifts in reference points, they provide an alternative to the concept of a Designated Community in the determination of preservation requirements, the identification of significant properties, the creation of Representation Information and in the evaluation of success.Originality/valueThis article contributes a novel approach to the ongoing conversation about the Designated Community in digital preservation, its application and its limitations in an archival context.

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