A MARKOV REPAIRABLE SYSTEM INVOLVING AN IMPERFECT SERVICE STATION WITH MULTIPLE VACATIONS

2005 ◽  
Vol 22 (04) ◽  
pp. 555-582 ◽  
Author(s):  
JAU-CHUAN KE ◽  
CHUEN-HORNG LIN
Keyword(s):  
Repairable System ◽  
System Failure ◽  
Service Station ◽  
System Parameters ◽  
Failure Frequency ◽  
The Mean ◽  
Repair Facility ◽  
Markov Repairable System ◽  
Mean Time ◽  
Reliability And Availability

The main purpose of this paper is to study the reliability and availability of a system with M operating devices, m spares, and an imperfect service station that takes vacations. Specifically, once there are no failed devices in the system, the service station takes consecutive vacations until there is at least one failed device upon its return from vacation. The service station may break down and require repair at a repair facility. This paper derives the reliability, the mean time to system failure, the availability, and failure frequency of the K-out-of-M + m system. Numerical simulation of the impacts of system parameters as well as sensitivity analysis for the reliability, the mean time to system failure, the availability and failure frequency is performed.

scholarly journals Reliability and Availability Analysis of Arepairable System With Two Types of Failure

2015 ◽  
Vol 4 (1) ◽  
pp. 39
Author(s):  
M. A. El-Damcese ◽  
M. S. Shama
Keyword(s):  
System Reliability ◽  
Repairable System ◽  
Time To Failure ◽  
Repair Rate ◽  
System Parameters ◽  
Availability Analysis ◽  
Reliability Characteristics ◽  
The Mean ◽  
Mean Time ◽  
Reliability And Availability

This paper investigates reliability and availability of a repairable system with two types of failure. Let failure rate and repair rate of [type1, type2] components are assumed to be exponentially distributed. The expressions of availability and reliability characteristics such as the system reliability and the mean time to failure are derived. We used several cases to analyze graphically the effect of various system parameters on the reliability system and availability system.

scholarly journals Multi-Machine Repairable System with One Unreliable Server and Variable Repair Rate

Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1299
Author(s):  
Shengli Lv
Keyword(s):  
Steady State ◽  
Transient State ◽  
Repairable System ◽  
Repair Rate ◽  
Numerical Illustration ◽  
Transform Method ◽  
Unreliable Server ◽  
Busy Time ◽  
The Mean ◽  
Mean Time

This paper analyzed the multi-machine repairable system with one unreliable server and one repairman. The machines may break at any time. One server oversees servicing the machine breakdown. The server may fail at any time with different failure rates in idle time and busy time. One repairman is responsible for repairing the server failure; the repair rate is variable to adapt to whether the machines are all functioning normally or not. All the time distributions are exponential. Using the quasi-birth-death(QBD) process theory, the steady-state availability of the machines, the steady-state availability of the server, and other steady-state indices of the system are given. The transient-state indices of the system, including the reliability of the machines and the reliability of the server, are obtained by solving the transient-state probabilistic differential equations. The Laplace–Stieltjes transform method is used to ascertain the mean time to the first breakdown of the system and the mean time to the first failure of the server. The case analysis and numerical illustration are presented to visualize the effects of the system parameters on various performance indices.

scholarly journals DEGRADATION ANALYSIS OF PROBABILISTIC PARALLEL CHOICE SYSTEMS

2014 ◽  
Vol 21 (03) ◽  
pp. 1450012
Author(s):  
AVINASH SAXENA ◽  
SHRISHA RAO
Keyword(s):  
Complete System ◽  
System Failure ◽  
Time To Failure ◽  
Probabilistic Choice ◽  
Mean Time Between Failures ◽  
System Parameters ◽  
Time Between Failures ◽  
Degradation Analysis ◽  
Mean Time ◽  
Selection Of

Degradation analysis is used to analyze the useful lifetimes of systems, their failure rates, and various other system parameters like mean time to failure (MTTF), mean time between failures (MTBF), and the system failure rate (SFR). In many systems, certain possible parallel paths of execution that have greater chances of success are preferred over others. Thus we introduce here the concept of probabilistic parallel choice. We use binary and n-ary probabilistic choice operators in describing the selections of parallel paths. These binary and n-ary probabilistic choice operators are considered so as to represent the complete system (described as a series-parallel system) in terms of the probabilities of selection of parallel paths and their relevant parameters. Our approach allows us to derive new and generalized formulae for system parameters like MTTF, MTBF, and SFR. We use a generalized exponential distribution, allowing distinct installation times for individual components, and use this model to derive expressions for such system parameters.

scholarly journals Reliability optimization on power systems network using genetic algorithm

2020 ◽  
Vol 2 ◽  
pp. 18-29
Author(s):  
A. E. Airoboman ◽  
Emmanuel A. Ogujor
Keyword(s):  
Genetic Algorithm ◽  
Power Systems ◽  
Inequality Constraints ◽  
Optimization Approach ◽  
Reliability Optimization ◽  
Equality And Inequality Constraints ◽  
The Mean ◽  
Mean Time ◽  
Reliability And Availability ◽  
Selection Of

In this study, reliability optimization of a non-linear transmission network using Genetic Algorithm (GA) based optimization approach is presented and proposed. A GA based algorithm was developed for Koko, Guinness, Nekpenekpen, Ikpoba-Dam, Switch station, Etete and GRA 33kV tertiary transmission feeders within Benin Metropolis, Nigeria and was used to determine the optimal performance of the feeders’ reliability and availability through the minimization of downtime and the Mean Time between Failure (MTBF) by the appropriate selection of the objective functions and constraints. The equality and inequality constraints for each feeder on the network were defined, thereafter, codes were written on the Matlab 2016a environment to optimize the selected parameters. The results from the study showed a reduction in downtime of 5.63%, 26.87%, 34.20%, 5.42% 8.37%, 5.18% and 10.97% and an increment increased in MTBF by 4.95%, 19.87%, 4.58%, 3.85%, 4.88%, 5.77% and 13.56% for Guinness, Etete, Nekpenekpen, GRA, Switch station and Ikpoba-Dam feeders respectively. The obtained results, therefore, yielded an average corresponding improvement on the network’s reliability and availability by 1.85% and 2.83% respectively. Conclusively, the desired result reached in this paper validates the robustness of the GA tool in reliability studies. However, conscious effort must be geared concerning the ways and manners the system is operated in order to achieve desired results.

A Method for the Calculation of the Mean Time To Failure (MTTF) of Repairable System

2008 ◽  
Vol 44-46 ◽  
pp. 813-820 ◽  
Author(s):  
Jian Xin Zhu ◽  
Li J. Wang ◽  
Shi Yi Bao ◽  
W.P. Wang ◽  
Zeng Liang Gao
Keyword(s):  
Single Unit ◽  
Management Strategy ◽  
Great Influence ◽  
Repairable System ◽  
Time To Failure ◽  
Test Interval ◽  
Operating Cycle ◽  
Mean Time To Failure ◽  
The Mean ◽  
Mean Time

The ability of executing assigned function of repairable system under certain condition is quite different from that of single unit due to redundant configuration. It is well understood that proper management strategy can greatly prolong the mean time to failure (MTTF) of repairable system. By introducing operating cycle or partial test interval, repair time and maintenance efficiency, the MTTF of classic 1oo1, 1oo2 and 2oo3 redundant systems is studied in this paper. It is found that periodical maintenance can dramatically improve the availability of repairable system, while the efficiency of maintenance has great influence on the MTTF of repairable system.

Predicting Daily Maintenance Dose of Fluindione, an Oral Anticoagulant Drug

1996 ◽  
Vol 75 (05) ◽  
pp. 731-733 ◽  
Author(s):  
V Cazaux ◽  
B Gauthier ◽  
A Elias ◽  
D Lefebvre ◽  
J Tredez ◽  
...  
Keyword(s):  
Effective Dose ◽  
Maintenance Dose ◽  
Successive Approximations ◽  
Hemorrhagic Complication ◽  
Simple Method ◽  
Individual Variations ◽  
Anticoagulant Drug ◽  
The Mean ◽  
Mean Time ◽  
Daily Maintenance Dose

SummaryDue to large inter-individual variations, the dose of vitamin K antagonist required to target the desired hypocoagulability is hardly predictible for a given patient, and the time needed to reach therapeutic equilibrium may be excessively long. This work reports on a simple method for predicting the daily maintenance dose of fluindione after the third intake. In a first step, 37 patients were delivered 20 mg of fluindione once a day, at 6 p.m. for 3 consecutive days. On the morning of the 4th day an INR was performed. During the following days the dose was adjusted to target an INR between 2 and 3. There was a good correlation (r = 0.83, p<0.001) between the INR performed on the morning of day 4 and the daily maintenance dose determined later by successive approximations. This allowed us to write a decisional algorithm to predict the effective maintenance dose of fluindione from the INR performed on day 4. The usefulness and the safety of this approach was tested in a second prospective study on 46 patients receiving fluindione according to the same initial scheme. The predicted dose was compared to the effective dose soon after having reached the equilibrium, then 30 and 90 days after. To within 5 mg (one quarter of a tablet), the predicted dose was the effective dose in 98%, 86% and 81% of the patients at the 3 times respectively. The mean time needed to reach the therapeutic equilibrium was reduced from 13 days in the first study to 6 days in the second study. No hemorrhagic complication occurred. Thus the strategy formerly developed to predict the daily maintenance dose of warfarin from the prothrombin time ratio or the thrombotest performed 3 days after starting the treatment may also be applied to fluindione and the INR measurement.

Inspecting Briquette Machine with Different Faults

2020 ◽  
Vol 13 ◽  
Author(s):  
Divesh Garg ◽  
Reena Garg ◽  
Vanita Garg
Keyword(s):  
Failure Rate ◽  
Rate Increase ◽  
Practical Importance ◽  
System Failure ◽  
Regenerative Point ◽  
Semi Markov Process ◽  
Major Fault ◽  
Environment Study ◽  
Burning Coal ◽  
Mean Time

Background: A briquette machine can be considered very useful in modern times as the need of energy consumption is increasing rapidly. Considering the harm to environment, study of briquette machine is the need of present times. In this paper, the operative unit is considered as briquette machine also known as bio-coal which is used for agroforestry waste. Objective: A single operative unit has been analyzed stochastically. The inspection of breakdown of a unit reveals the feasibility of the unit under the supervision of either ordinary or expert repairmen. Two types of fault are revealed by the repairmen either minor or major fault. Minor faults are repaired immediately by the same repairmen but whenever major fault held, the machine’s fault will be handled by expert person. Method: It is assumed that the repair needs no modification once served. Availability, Mean-time for system failure, and profits are analyzed by utilizing the Regenerative point graphical technique and semi-Markov process. Result: Study reveals that the Mean-time for system failure of the system model go on decreasing as failure rate increase and availability goes on decreasing as failure-rate increase. Moreover, the study shows that the systems profit goes down on increase of Failure-rate. Conclusion: Findings of the study supports the hypothesis that the limits of failure/repair/inspection rate will surely have effective profitability. Moreover, it is found that the utility of scale of operation can easily be derived. The practical importance of biomass briquettes for burning coal or wood is very well appreciated.

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