@article { author = {elghamry, eman and eldamcesse, medhat and nayel, mohamed}, title = {Reliability Model of Fuzzy Consecutive k-out-of-n: F System}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {2}, number = {1}, pages = {1-4}, year = {2019}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/ijrrs.2.1.1}, abstract = {Redundancy can be used to increase system reliability. The most popular type of redundancy, k-out-of-n system structure, finds wide applications in both industrial and military systems. Aspecial type of this system is the consecutive k-out-of-n:F system C(k,n:F) which have been proposed for reliability evaluation and integrated circuits design, microwave relay stations in telecommunication system, oil pipelines systems, vacuum systems in accelerators, computer ring networks, and spacecraft relay stations. In this paper, we will discuss a new algorithm for evaluating the fuzzy reliability of any fuzzy linear consecutive k-out-of-n:Fsystem (Lin/C(k,n:F)) with independent, unrepairable, and non-identical components.Later,we will introduce a model of unrepairable system consists of parallel subsystems if each subsystem is Lin/C(k,n:F). Due to uncertainty and insufficient data, failure time of each component follows fuzzy Rayleigh distribution with one fuzzy parameter. This fuzzy parameter is represented by triangular membership function and estimated from statistical data taken from random samples of each component. Furthermore, a numerical example for a fuzzy unrepairable parallel system with three subsystems is given while eachsystem is represented by Lin/C(k,n:F).Also, the failure time of each component follows fuzzy Rayleigh distribution to get analytically and represents the fuzzy reliability function of this fuzzy system graphically.}, keywords = {Consecutive k-out-of-n:F system,Rayleigh Distribution,Fuzzy Parameters,Reliability,Linear system}, url = {http://www.ijrrs.com/article_81435.html}, eprint = {http://www.ijrrs.com/article_81435_63e51a309090b5f8e2008cc4aeb37a51.pdf} } @article { author = {SINGH, VIJAY and POONIA, PRAVEEN}, title = {Probabilistic Assessment of Two-Unit Parallel System with Correlated Lifetime under Inspection Using Regenerative Point Technique}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {2}, number = {1}, pages = {5-14}, year = {2019}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/ijrrs.2.1.2}, abstract = {This paper deals with the reliability analysis of a complex system consisting ofa two dissimilar unit’ in a parallel configuration with correlated lifetime distribution. The system stops functioning when both units stop working. Both units are inspected periodically as well as being examined before assigning to repair facility. Under consideration of the system have two states: Normal and failed. Regenerative point technique has been used for the mathematical formulation of the model. The system is analyzed using Laplace transforms to solve the mathematical equations. Reliability, Availability, MTSF, Busy Period of repairmen and Cost-effectiveness of the system has been computed. The computed results have been demonstrated by tables and graphs. The repair time of both the units follows the negative exponential distribution with different parameters in a joint probability density function. The inspection times are assumed to follow the general distribution. Some particular cases of the system have also been derived from seeing the practical importance of the model.}, keywords = {Reliability,MTSF,Sojourn Times,Availability,Busy time,Profit function}, url = {http://www.ijrrs.com/article_88635.html}, eprint = {http://www.ijrrs.com/article_88635_de980ae079cd1a8ed591f74bb4855200.pdf} } @article { author = {Hoseyni, Seyed Mojtaba and Calissano, Anna}, title = {Moving from One Site to Multi-Site Vulnerability Studies: Decision Analysis for Trade-off Between Risks and Benefits}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {2}, number = {1}, pages = {15-21}, year = {2019}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/ijrrs.2.1.3}, abstract = {This paper provides a vulnerability study for a gas production site. Decision tree analysis is implemented to provide risk-informed decisions on the maintenance strategies to minimize the unavailability and downtime costs. In this context, the decision analysis assesses the impact on the availability of the plant after having decided to buy some spare parts to mitigate the criticality of some equipment. This will help the decision makers to make an optimal decision before spending their budget on buying the spare parts while they can reliably forecast a maximizedavailability. The decision analysis also will move from onesite approach to the multi-site vulnerability studies. Result concludes a recommendation for the company on deciding the optimum maintenance strategies and provides a list of required spare parts to be bought in advance to reduce the associated risks and costs.}, keywords = {decision analysis,Maintenance Decision,risk,vulnerability}, url = {http://www.ijrrs.com/article_91332.html}, eprint = {http://www.ijrrs.com/article_91332_d54fffb341c2231466ed68b626778560.pdf} } @article { author = {Farsi, Mohammad Ali and Zio, Enrico}, title = {Industry 4.0: Some Challenges and Opportunities for Reliability Engineering}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {2}, number = {1}, pages = {23-34}, year = {2019}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/ijrrs.2.1.4}, abstract = {According to the development of Industry 4.0 and increase the integration of digital, physical and human worlds, reliability engineering must evolve for addressing the existing and future challenges about that. In this paper, the principle of Industry 4.0 is presented and some of these challenges and opportunities for reliability engineering are discussed. New directions for research in system modeling, big data analysis, health management, cyber-physical system, human-machine interaction, uncertainty, jointly optimization, communication, and interfaces are proposed. Each topic can be investigated individually, but this paper summarizes them and prepared a vision about reliability engineering for consideration and discussion by the interested scientific community.}, keywords = {Reliability engineering,Industry 4.0,Challenges,Big Data,Health management,cyber-physical system,Human-machine interaction,jointly optimization,communication and interfaces}, url = {http://www.ijrrs.com/article_91148.html}, eprint = {http://www.ijrrs.com/article_91148_1c23077d2249f68e3da94b3ada8998a1.pdf} } @article { author = {Hajivand, Mohammad and Zahedi Vahid, Masoud and Goudarzvand Chegini, Farzad and Rahmati-Kahkha, Poorya and Hajivand, Reza}, title = {Optimization of Electrical Distribution System Maintenance Process Based on Failure Modes}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {2}, number = {1}, pages = {35-42}, year = {2019}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/ijrrs.2.1.5}, abstract = {This paper presents a novel scheme for comprehensive planning of reliability-centered maintenance (RCM) in the electrical distribution system to minimize the costs of cable repair and maintenance. To this end, a new formulation is proposed by taking into account the maintenance costs for different cases, repairs, repair-caused load projects, and energy purchase or generation costs. To solve the given complex problem, one of the most powerful and newest particle intelligence techniques called GSO algorithm is employed. Simulations are carried out on a 30-bus test network. Moreover, three scenarios and ten cases are applied in the process of extracting results to analyze the impact of various items on parameters of the objective function.}, keywords = {Reliability-Centered Maintenance,Markov model,Distribution network,Group Search Optimization}, url = {http://www.ijrrs.com/article_95852.html}, eprint = {http://www.ijrrs.com/article_95852_ff7f3f4f1b1657afbd903135a319ab12.pdf} } @article { author = {Alikhani, Alireza and Dehghan M., Safa and Shafieenejad, Iman}, title = {Fault Tolerant Guidance of Under-Actuated Satellite Formation Flying Using Inter-Vehicle Coulomb Force}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {2}, number = {1}, pages = {43-52}, year = {2019}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/ijrrs.2.1.6}, abstract = {In this study, satellite formation flying guidance in the presence of under actuation using inter-vehicle Coulomb force is investigated. The Coulomb forces are used to stabilize the formation flying mission. For this purpose, the charge of satellites is determined to create appropriate attraction and repulsion and also, to maintain the distance between satellites. Static Coulomb formation of satellites equations including three satellites in triangular form was developed. Furthermore, the charge value of the Coulomb propulsion system required for such formation was obtained. Considering Under actuation of one of the formation satellites, the fault-tolerance approach is proposed for achieving mission goals. Following this approach, in the first step fault-tolerant guidance law is designed. Accordingly, the obtained results show stationary formation. In the next step, tomaintain the formation shape and dimension, a fault-tolerant control law is designed.}, keywords = {formation flying,Guidance law,Under actuation,Coulomb force}, url = {http://www.ijrrs.com/article_92136.html}, eprint = {http://www.ijrrs.com/article_92136_2259532914034ca9e64ddff87d845b67.pdf} }