Reliability of mission-based k-out-of-n systems with exponential phase durations and component lifetimes

2020 ◽  
pp. 1748006X2096930
Author(s):  
Bora Çekyay
Keyword(s):  
System Reliability ◽  
Transition Probabilities ◽  
General System ◽  
System Structure ◽  
Time To Failure ◽  
Long Run ◽  
Reliability Characteristics ◽  
Mission Change ◽  
Component Failure Rates ◽  
Mean Time

This paper focuses on the reliability analysis of [Formula: see text]-out-of-[Formula: see text] systems which are designed to perform a given mission consisting of several distinct phases. As the phases of the mission change, the reliability characteristics of the system and the system structure vary accordingly. The phase transition probabilities, phase durations, and component failure rates are dependent on the number of operating components. Moreover, the system is allowed to have cold, warm, or hot standby components. We propose computationally tractable methods to compute the system reliability, mean time to failure, and long-run availability for such a general system structure. We also provide a numerical analysis to show the applicability and the empirical computational complexity of the proposed methods.

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 Effect of Grid Instability on Power Generation System's Reliability

2020 ◽  
pp. 27-37
Author(s):  
Joseph Benedict Bassey ◽  
Isaac F. Odesola
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Failure Rate ◽  
System Reliability ◽  
Power Distribution ◽  
Power Plants ◽  
Time To Failure ◽  
Generation System ◽  
Reliability Indices ◽  
Mean Time

Aims: Reliability assessment of power generation system may be performed with the concept of system adequacy, security or both. Grid being a major component in the power distribution chain is seen to have some influence on the state of the generation system reliability because of the perturbation that may arise from it. In this study, the generation system reliability is evaluated using both the system adequacy and security concept. Study Design: To capture the system security problems attributed to grid disturbance, the generation system is structured into two component systems (1 - generation component and 2 - transmission component) with a series arrangement. Methodology: The reliability indices such as, mean time to failure, mean time to repair, failure rate and repair rate are assessed on component bases and with respect to the entire generation system. Results: The effect of failure rate of the transmission component on the entire generation system failure rate was evaluated as 66.25%, 55.55%, 33.33%, 55.00% and 35.72% in year 2013, 2014, 2017 2018 and 2019 respectively for FIPL Power Plant and 52.94%, 82.35%, 61.38% and 100% effect was evaluated in the year 2016, 2017, 2018 and 2019 respectively for GT5 of Omoku Power Plant. Conclusion: These results showed that there is a significant influence of grid disturbances on the reliability state of the two gas turbine power plants in Nigeria. Measures on possible reliability state improvement of the power generation systems were suggested to include training and retraining of technical personnel on the management of major equipment in the generation and transmission stations. 

Research on Spurious Trip of 1oo2 Safety Instruments of Petrochemical Installation with Repair Considered

2010 ◽  
Vol 118-120 ◽  
pp. 596-600
Author(s):  
Jian Xin Zhu ◽  
Xue Dong Chen ◽  
Shi Yi Bao
Keyword(s):  
Failure Rate ◽  
System Reliability ◽  
Repairable System ◽  
Time To Failure ◽  
Redundant System ◽  
Common Cause ◽  
System A ◽  
Definition Of ◽  
Mean Time ◽  
Complex Influence

An innovative nuisance trip calculation method based on Markov model was proposed in this paper which was used to evaluate the effect of repairment on system reliability. By analysis of the availabilities of classic 1 out of 2 (1oo2) repairable system, a new definition of spurious trip was put forwarded where online repair was considered. Compared with the benefits obtained by online repairment, the repair-caused-nuisance-trip was analyzed in this paper. Numerical calculation revealed that the online repair is helpful for anti-spurious trip in 1oo2 redundant system. Dangerous failures, if not repaired or cannot be online fixed, have complex influence on system reliability. The dangerous failure is sometimes benefit for anti-spurious performance if it is not repaired. But Mean Time To Failure Spurious (MTTFs) reduces with the increase of dangerous failure provided that dangerous failure rate is bigger than safe failure rate. Meanwhile, the finding that common cause can reduce the chance of nuisance trip was also proposed in this paper, though the influence is too small to be neglected.

scholarly journals R-effect of decomposition of duplicate systems into equiprobable functional nodes

2020 ◽  
Vol 2 ◽  
pp. 117-123
Author(s):  
O.V. Fedukhin ◽  
Keyword(s):  
Operating Mode ◽  
Channel Structure ◽  
System Structure ◽  
Time To Failure ◽  
Channel System ◽  
Redundancy Level ◽  
Serial Connection ◽  
Automation Systems ◽  
Fail Safe ◽  
Mean Time

The work is devoted to the reliability of non-recoverable two-channel automation systems and computer equipment. As alternative options, a system with block duplication (SBD) and a system with a quasi-bridge structure (QBS) are considered. SBD in general is a two-channel system consisting of a series connection of duplicated nodes of different reliability. In case of failure of one of the functional subunits (FSU) of the duplicated node using the control and reconfiguration (SCR) scheme, it is masked, withdrawn from the computational process, and reconfigured the system structure in the “Non Stop” operating mode. A QBS system also represents a two-channel structure, but consisting of a serial connection of duplicated nodes of equal reliability, while the technical element intensity (redundancy level) and the functionality of this system are identical to SPD. The QBS system is also a fail-safe system that provides the “Non Stop” mode of operation. The probabilistic-physical calculation method (WF-method) is used as a tool for studying the reliability of systems, which is based on the diffusion distribution of mean-time-to-failure (DN-distribution), specially formalized for assessing the reliability of electronic, electrical and electromechanical elements and systems. While maintaining the redundancy level of the considered two-channel redundant systems, decomposing the channels into equally reliable duplicated nodes leads to the R-effect – an increase in the likelihood of system uptime with an increase in the number of nodes. The presence of the R-effect was established by other methods of calculation and by statistical modeling for both non-restored and restored systems.

Reliability analysis of distributed storage systems considering data loss and theft

2019 ◽  
Vol 234 (2) ◽  
pp. 303-321
Author(s):  
Heping Jia ◽  
Rui Peng ◽  
Yi Ding ◽  
Changzheng Shao
Keyword(s):  
System Reliability ◽  
Storage Systems ◽  
Distributed Storage ◽  
System Structure ◽  
Time To Failure ◽  
Data Loss ◽  
Exponential Distributions ◽  
Basic Model ◽  
Distributed Storage Systems ◽  
Dependence Property

With the advancement of cloud computing and internet of things, data are usually stored on distributed computers and these data may risk being lost or stolen. In this article, we consider a common case where the entirety of the data is partitioned into several parts and each data part can be allocated to one or more computers. In the case where a computer fails, all the data parts on it are lost. Before the failure of any computer, the data parts may also be stolen by hackers. The basic model of computer failure and computer intrusion resulting in the theft of all the data parts on the computer is considered first. Then, the case is extended to a general model where computer failure, as well as data part corruption and theft caused by hacking are embedded. It is essential to study the reliability of distributed storage systems considering both data loss and data theft, which can be a basis for decision making on system structure optimization. In this article, a multi-valued decision diagram–based approach is developed to quantitatively evaluate system reliability for both models considering the time-dependence property of sequential events. The proposed method is applicable to systems where the random time to failure, theft, or corruption follows arbitrary distributions including the commonly used exponential distributions. Illustrative examples are provided to validate the proposed method.

Signature reliability of binary state node in complex bridge networks using universal generating function

2019 ◽  
Vol 36 (2) ◽  
pp. 186-201 ◽  
Author(s):  
Soni Bisht ◽  
S.B. Singh
Keyword(s):  
Generating Function ◽  
Time To Failure ◽  
Content Type ◽  
Reliability Indices ◽  
The Past ◽  
Reliability Characteristics ◽  
Binary State ◽  
Bridge Networks ◽  
Mean Time ◽  
Universal Generating Function

PurposeThe purpose of this paper is to evaluate various reliability measures like reliability, expected lifetime (mean time to failure), signature reliability and compare networks based on the different flows.Design/methodology/approachThe reliability characteristics of complex bridge networks have been evaluated using different algorithms with the help of universal generating function (UGF). Further, the signature reliability of the considered networks has been determined using Owen’s method.FindingsThe present paper proposes an efficient algorithm to compute the reliability indices of complex bridge networks having i.i.d. lifetime components (nodes, edges) with the help of UGF and Owen’s method. This study reveals that a slight change in the complex bridge network affects the reliability significantly. Finally, by the reliability structure function, proposed algorithms are used to find the signature and MTTF. From signature, we have determined the different failure probabilities corresponding to edges of the network.Originality/valueIn this work, we have evaluated reliability characteristics and signature reliability of the complex bridge networks using UGF method and Owen’s method respectively unlike done in the past.

Fuzzy System Reliability Using Fuzzy Lifetime Distribution Emphasizing Octagonal Intuitionistic Fuzzy Numbers

2021 ◽  
pp. 192-208
Author(s):  
Pawan Kumar
Keyword(s):  
System Reliability ◽  
Fuzzy System ◽  
Fuzzy Numbers ◽  
Time To Failure ◽  
Fuzzy Reliability ◽  
Mean Time To Failure ◽  
Intuitionistic Fuzzy Numbers ◽  
Intuitionistic Fuzzy ◽  
Fuzzy Mean ◽  
Mean Time

The present study proposes to determine the fuzzy reliability of different systems in which the lifetime of components are following fuzzy exponential distribution where fuzzy reliability function and its α-cut set are presented. The fuzzy reliability of different systems is defined on the basis of octagonal intuitionistic fuzzy numbers. The fuzzy reliability functions of k-out-of-m system, series system, parallel systems, and their fuzzy mean time to failure are discussed respectively using the concept of α-cut of octagonal intuitionistic fuzzy numbers. Finally, some numerical examples are discussed to illustrate how to calculate the fuzzy system reliability and α-cut of fuzzy mean time to failure (FMTTF).

scholarly journals Surveillance System in Smart Cities: A Dependability Evaluation Based on Stochastic Models

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 876
Author(s):  
Igor Gonçalves ◽  
Laécio Rodrigues ◽  
Francisco Airton Silva ◽  
Tuan Anh Nguyen ◽  
Dugki Min ◽  
...  
Keyword(s):  
Surveillance System ◽  
Smart Cities ◽  
Heterogeneous Data ◽  
Time To Failure ◽  
Video Streams ◽  
Dependability Evaluation ◽  
The Mean ◽  
Mean Time ◽  
The Internet Of Things

Surveillance monitoring systems are highly necessary, aiming to prevent many social problems in smart cities. The internet of things (IoT) nowadays offers a variety of technologies to capture and process massive and heterogeneous data. Due to the fact that (i) advanced analyses of video streams are performed on powerful recording devices; while (ii) surveillance monitoring services require high availability levels in the way that the service must remain connected, for example, to a connection network that offers higher speed than conventional connections; and that (iii) the trust-worthy dependability of a surveillance system depends on various factors, it is not easy to identify which components/devices in a system architecture have the most impact on the dependability for a specific surveillance system in smart cities. In this paper, we developed stochastic Petri net models for a surveillance monitoring system with regard to varying several parameters to obtain the highest dependability. Two main metrics of interest in the dependability of a surveillance system including reliability and availability were analyzed in a comprehensive manner. The analysis results show that the variation in the number of long-term evolution (LTE)-based stations contributes to a number of nines (#9s) increase in availability. The obtained results show that the variation of the mean time to failure (MTTF) of surveillance cameras exposes a high impact on the reliability of the system. The findings of this work have the potential of assisting system architects in planning more optimized systems in this field based on the proposed models.

scholarly journals Modelling Reliability Characteristics of Technical Equipment of Local Area Computer Networks

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 955
Author(s):  
Vasyl Teslyuk ◽  
Andriy Sydor ◽  
Vincent Karovič ◽  
Olena Pavliuk ◽  
Iryna Kazymyra
Keyword(s):  
Large Scale ◽  
Computer Network ◽  
Network Reliability ◽  
Local Area ◽  
Technical Equipment ◽  
Time To Failure ◽  
Reliability Parameters ◽  
Reliability Characteristics ◽  
Global World ◽  
Level 2

Technical systems in the modern global world are rapidly evolving and improving. In most cases, these are large-scale multi-level systems and one of the problems that arises in the design process of such systems is to determine their reliability. Accordingly, in the paper, a mathematical model based on the Weibull distribution has been developed for determining a computer network reliability. In order to simplify calculating the reliability characteristics, the system is considered to be a hierarchical one, ramified to level 2, with bypass through the level. The developed model allows us to define the following parameters: the probability distribution of the count of working output elements, the availability function of the system, the duration of the system’s stay in each of its working states, and the duration of the system’s stay in the prescribed availability condition. The accuracy of the developed model is high. It can be used to determine the reliability parameters of the large, hierarchical, ramified systems. The research results of modelling a local area computer network are presented. In particular, we obtained the following best option for connecting workstations: 4 of them are connected to the main hub, and the rest (16) are connected to the second level hub, with a time to failure of 4818 h.

Sign in / Sign up

Export Citation Format

Share Document