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# Optimizing Reliability Model by Using Meta Heuristic Algorithm

Dissertation
by

## Masih Miriha

on 15 February 2013

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#### Transcript of Optimizing Reliability Model by Using Meta Heuristic Algorithm

LITERATURE REVIEW Research Methodology Keyword & definition Optimizing of Reliability Model Using a Meta Heuristic Algorithm

Prepared By:
Masih Miriha

Supervisor:
Assoc. Prof. Dr. Adnan Hassan OUTLINE OF PRESENTATION Failure Everything may fail. Maybe you have experience in one of the following options in your life:
Washing machine has a problem, toaster breaks down suddenly, battery discharges, remote doesn’t work and a hole is created on part of roof. British Standard Glossary of terms (3811:1993) defined maintenance as:
combination of all technical and administrative actions, including supervision actions, intended to retain an item in, or restore it to, a state in which it can perform a required function.
Probability that a system or product will perform in a satisfactory manner for a given period of time when used under specified operating condition Maintenance Reliability Problem Background Improvement of system maintenance in a important topic in real world or in industry Redundancy allocation is one of the main part in reliability because in real world systems was designed so to improve them redundancy object is a suitable method Nowadays focus on reliability to increase a life cycle of the products is a challenging topic in real world. Optimizing system reliability is play important role in world and many researcher use mathematical method to increase it. It is easy to use rather than others. It finds a solution faster than others. It finds a better optimum solution rather than other algorithm. This algorithm in redundancy allocation is more formal than others.
Genetic Algorithm (GA) Significance of study 4. K-out-of-n system Figure2: Examples of Parallel models Figure3: Examples of series parallel models Calculate reliability Figure1: Examples of series models 2. 3. 1. Series system Combine series and parallel Parallel system 1) Rs (t) = R1 (t) × R2 (t) × R3 (t) ×…. Rn (t) ≤ min {R1 (t), R2 (t), R3 (t), … ,Rn (t)
2) Rs(t)= [1-R1(t)] ×[1-R2(t)] ×…× [1-Rn(t)] ≥ max { R1(t), R2(t), … , Rn(t)}
3) finding reliability of model three, depend on figure which made the model
4) Definition of k-out-of-n systems is: When a system with n components works (or is “good”) if and only if at least k of the n components work (or are “good”) Redundancy allocation is to select the best components and redundancy for each subsystem in order to maximize the system reliability under system- level constraints such as cost, weight and volume Two different type of redundancy Active
system Standby system failure rate of spare object is equal to the other component of system Hot Standby System Warm Standby System Cold Standby system Hot standby system is very similar to active redundancy’s definition so it is formulated and calculated like active system Warm standby system has a failure rate like active system but this failure rate is less than hot or active system. Failure rate In cold standby system is approximately zero and researcher assumes that is equal to zero Keyword & definition Reliability Models Fyffe et al. (1968) to select the optimal solution in reliability model

He is a first person who try to optimize a reliability model
Dynamic method Coit etal. (2000) Solve different model in reliability with different method
series-parallel
K-out-of-n system
Dynamic algorithm
0&1 (integer programming)
GA Tavakkoli-Moghaddam et al. (2007) Optimize a series-parallel system with a choice of redundancy
GA Finding gap Fyffe et al. found cold standby system conform of Erlangen distribution(1986)

Dynamic programming Coit et al. presented a problem formulation and solution method to determine the optimal system reliability.(1996&2000)

GA Coit et al. optimized a new problem formulation and solution for a system includes multiple subsystems that are designed with either active or cold-standby redundancy.(2003)

zero-one integer programming method Tavakkoli-Moghaddam et al. prepare a problem formulation and solution method to determine the optimal system design configuration when switch is required in active and cold standby posture.(2008)

GA Mani Sharifi et al. find a model for active redundancy model in k-out-of-n system.(2010) This research try to Optimize a model with combine cold standby and active redundancy allocation in k-out-of-n System with decrease failure rate in certain cost and weight constraints 1.System has s series different subsystems.

2.All of the subsystems are k-out-of-n system.

3.Policy of any subsystem maybe active or cold standby.

4.Failure rate of components in each subsystem is constant.

5.Failure rate depends on the number of working elements.

6. Components are not repairable, they are changeable only.