Reliability Evaluation of Two-Stage Directed Semi-Markov Repairable Network Systems

A two-stage directed Semi-Markov repairable network system is presented in this paper to model the performance of many transmission systems, such as power or oil transmission network, water or gas supply network, etc. The availability of the system is discussed by using Markov renewal theory, Laplace transform and probability analysis methods. A numerical example is given to illustrate the results obtained in the paper.

Evaluation of the Reliability of a System: Approach by Monte Carlo Simulation and Application

The objective of this paper is to evaluate the reliability of a system in its different states (absence of failures, partial failure and total failure) and to propose actions to improve this reliability by an approach based on Monte Carlo simulation. It consists of a probabilistic evaluation based on Markov Chains. In order to achieve this goal, the functionalities of Markov Chains and Monte Carlo simulation steps are deployed. The application is made on a production system. .

Validity and reliability of the evaluation tool of TCM confidence in students with TCM learning experience

Objective:This study aimed to design an evaluation scale of traditional Chinese medicine(TCM)confidence and then evaluate its validity and reliability.Methods:Three parallel samples with TCM learning experience were included in this current study.Randomly selected 500 nursing students were included factor analysis and reliability and validity analyses.After 4 weeks,200 nursing students were recruited to retest the reliability.The evaluation tool of TCM confidence included 6 dimensions and 25 entries.Results:Cronbach's a coefficient of the evaluation scale was 0.95 and that of the 6 observed aspects were higher than 0.90,and splithalf reliability was 0.81.For the retest reliability,Cronbach's a coefficient of the evaluation scale was 0.93 and that of the 6 examined aspects was all over 0.80.The index of content validity Scale Content Validity Index(S-CVI)was 0.92 and Item Content Validity Index(I-CVI)was 0.83–1.00.Conclusions:Observed results may indicate that the designed tool can be used to assess the TCM confidence level of students with TCM studied experience and also can evaluate results of TCM education during studying TCM lectures.

Reliability Evaluation of Machine Center Components Based on Cascading Failure Analysis

In order to rectify the problems that the com- ponent reliability model exhibits deviation, and the evalu- ation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine center components, a new reliability evaluation method based on cascading failure analysis and the failure influ- enced degree assessment is proposed. A direct graph model of cascading failure among components is established according to cascading failure mechanism analysis and graph theory. The failure influenced degrees of the system components are assessed by the adjacency matrix and its transposition, combined with the Pagerank algorithm. Based on the comprehensive failure probability function and total probability formula, the inherent failure proba- bility function is determined to realize the reliability evaluation of the system components. Finally, the method is applied to a machine center, it shows the following： 1） The reliability evaluation values of the proposed method are at least 2.5% higher than those of the traditional method; 2） The difference between the comprehensive and inherent reliability of the system component presents a positive correlation with the failure influenced degree ofthe system component, which provides a theoretical basis for reliability allocation of machine center system.

RELIABILITY ANALYSIS FOR A REPAIRABLE PARALLEL SYSTEM WITH TIME-VARYING FAILURE RATES

To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,and obtains calculating formulas of reliability and availability of the system by solving differential equations.In this paper,the failure rates are expressed in polynomial configuration.The constant,linear and Weibull failure rate are in their special form.The polynomial failure rates provide flexibility in modeling the practical time-varying failure rates.

Simulation Evaluation Study of System Reliability Based on Improved BayesBootstrap Method

For the disadvantages of analyzing system reliability using common Bayes method,an evaluation method based on improved Bayes-Bootstrap method is presented.Firstly,the data obliteration problem existing in traditional Bayes method is analyzed,then an improved sampling arithmetic is proposed on the foundation of an experience function.Finally,effectiveness of this method is proved by an example.The simulating result shows that this method is more accurate than common Bayes method.

Reliability Evaluation of All-User Terminals in LEO Satellite Communication Network Based on Modular Reduction

LEO satellite communication network has a large number of satellites distributed in low orbits,which leads to multiple coverage of many areas on the ground.It is hard work to describe and evaluate the reliability of LEO satellite communication network.To solve this problem,the reliability of all-user terminals in LEO satellite communication network is defined,and the corresponding reliability evaluation method is proposed in the paper.Due to the large scale of the interstellar network,a modular reduction algorithm using the modular network instead of the original network for state decomposition is proposed in this paper.Case study shows that the calculation time of the proposed method is equivalent to 6.28%of the original state space decomposition algorithm.On this basis,the reliability of LEO satellite communication network is further analyzed.It is found that the reliability of LEO satellite network was more sensitive to the reliability of Inter-Satellite link and the satisfaction of global coverage in the early stage,and it is more sensitive to the reliability of the satellite in the later stage.The satellite-ground link has a relatively constant impact on of LEO satellite network.

A reliability evaluation method for embryonic cellular array based on Markov status graph model

Due to the limitations of the existing fault detection methods in the embryonic cellular array(ECA), the fault detection coverage cannot reach 100%. In order to evaluate the reliability of the ECA more accurately, embryonic cell and its input and output(I/O) resources are considered as a whole, named functional unit(FU). The FU fault detection coverage parameter is introduced to ECA reliability analysis, and a new ECA reliability evaluation method based on the Markov status graph model is proposed.Simulation experiment results indicate that the proposed ECA reliability evaluation method can evaluate the ECA reliability more effectively and accurately. Based on the proposed reliability evaluation method, the influence of parameters change on the ECA reliability is studied, and simulation experiment results show that ECA reliability can be improved by increasing the FU fault detection coverage and reducing the FU failure rate. In addition, by increasing the scale of the ECA, the reliability increases to the maximum first, and then it will decrease continuously. ECA reliability variation rules can not only provide theoretical guidance for the ECA optimization design, but also point out the direction for further research.

The Wartime Bridge Reliability Evaluation Model Based on Birth-and-Death Process

At first, the concept of bridge reliability is given, followed with its mathematic model. Then, based on the analysis about the mechanism of the damage and repair of bridges, and the state diversion of bridge network, the state diversion process is proved to be birth-and-death process. In the end, the state diversion balance equation of bridge network is built, and the evaluation model of wartime bridge reliability is got. The model is used in a certain example, and it is proved to be precise and credible.

Study on the Reliability Evaluation of Qualitative Indices in Multi-Objective Decision

Qualitative indices in multi-objective decision can usually be evaluated and measured by mathematical methods or models, but the obtained results are sometimes inaccurate because of fuzziness of indices. To improve the accuracy and reliability of the evaluation results, set-value statistic principle is applied, and accordingly four evaluation methods are obtained. Meanwhile, these methods are compared briefly.

PROBABILITY OF RANDOM EVENTS OF INSPECTION AND REPAIR AND MAINTAINING RELIABILITY OF STRUCTURES

Reliability analysis of the inspected and repaired structure requires dealing with a large number of complex random events. Considering many kinds of random factors, a probability of these random events existing possibly in the inspection and repair process and reliability analysis methodologies are proposed. A systematic dynamic reliability model is given for structures in service under the scheduled inspection and repair.

The System Analysis and Reliability Evaluation of Rock Slopes

The principal of preferred plane analysis is a new research view and model of rock slope engineering geology. It advocates that the rock slope stability, boundary conditions and failure model are controlled by preferred planes. Therefore, the problem of slope stability evaluation can be converted into the search for preferred planes and determination of preferred separating bodies. The organic combination of the deterministic model and the indeterministic model can be realized by applying the systems engineering principle and the research model and method of reliability analysis in the quantitative evaluation and prediction of rock slope stability. Finally, the paper presents the case studies of slopes of the Yangtze Gorge Project and the Ma'anshan openpit mine.

Reliability Analysis of Some Typical Repairable Systems with Arbitrary Repair-Time Distribution

In this paper, reliability of some typical non-Markov repairable systems, including series systems, m-out-of- n or majority vote systems, and n : m cross-strapping standby redundant systems with general repair-time distribution, are studied by applying the generalized Markov renewal process (GMRP). The stochastic behavior of the typical systems is analyzed here. Formulas for mean time to first system failure, MTBF, MTTR, and availability are then developed.

Instantaneous Reliability Index of a Typical Repairable System

A two-state system was taken as an example to show the method that we derived for analyzing the instantaneous reliability index,which was an important issue in the field of reliability.The paper first described the system as an abstract Cauchy problem by choosing suitable operators and state spaces.Then,with the TrotterKato theorem and strong continuous semi-group theorem,the method of solving the instantaneous reliability index of the repairable system was constructed.The convergence of the method was also proved in theory in this paper.To show the effectiveness of this method,some numerical examples were given at the end of the paper.

Research on Software Structure Analysis Technology and Reliability Evaluation Method of Warship Equipment

In view of the current reliability evaluation requirements of warship equipment based on component, this paper comprehensively considered the characteristics of components,and the component identification method, structural decomposition method,component architecture modeling method were studied for warship equipment software. Based on the characteristics of warship equipment component, this paper proposed a formal modeling language based on Petri nets to realize the modeling of component software architecture and laid a foundation for the reliability evaluation method research of warship equipment component.

Reliability Evaluation and Sensitivity Analysis for Multi-state System Based on Time Degradation Measures

The performance and state of multi-state system depend on its structure and different state combinations of the components. In order to evaluate the reliability of multi-state system effectively,a reliability evaluation and sensitivity analysis method based on the time degradation measures was proposed. The equivalence sets of the multi-state system under different output performances were established. The state combinations were classified according to the performance level. The degradation probability models under different states were established,and the new reliability measures,such as dynamic probability of multi-state system,holding time in each state,dynamic expectation function and integrated expectation function of the performance,were proposed and used to implement the dynamic reliability evaluation and sensitivity analysis. A certain diesel engine fuel feeding system was taken as an application example to illustrate the proposed method. The results show that not only the holding time in the desired state of the components and the system can be predicted,but also the best state component in a certain time period can be obtained.

Analysis of Stochastic Reliability Characteristics of a Repairable 2-out-of-3 System with Minimal Repair at Failure

In this paper, we study the reliability and availability characteristics of a repairable 2-out-of-3 system. Failure and repair times are assumed exponential. The explicit expressions of reliability and availability characteristics such as mean time to system failure (MTSF), steady-state availability, busy period and profit function are derived using Kolmogorov’s forward equations method. Various cases are analyzed graphically to investigate the impact of system parameters on MTSF, availability, busy period and profit function.

High-speed Railway External Power Supply Reliability Evaluation of Bayesian Network

Reliability evaluation is important in high speed railway external power supply design, based on probability reasoning bayesian network applied in high-speed railway external power supply reliability evaluation, establish the minimum cut and the minimum path of bayesian network model, quantitative calculation external power supply system in each element posterior probability, and the example analysis verified the feasibility and correctness of the above method. Using bayesian network bidirection reasoning technology, quantitative calculation the posterior probability of each element in external power supply system, realized the identification of weak link in external power supply. The research methods and the results of the study can be used in the scheme optimization design of high speed railway external power supply.

Reliability Evaluation of Mobile Communication Networks

A new reliability evaluation measure, global clustering reliability (GCR), is proposed. Firstly, the common measures used in invulnerability and survivability evaluation of mobile communication networks are discussed, and the shortcomings of these measures are pointed out. Then a new reliability evaluation measure, GCR, which is applicable to mobile communication networks, is proposed. And some properties and theorem about this measure are put forward. Finally, simulation calculation of reliability evaluation that uses this measure to 12 kinds of topological networks is accomplished. And the comparison between this measure and link connected factor (LCF) measure is also given. The results proved that the design of GCR is reasonable, its computation is rapid, moreover, it can take into account of invalidation of both nodes and links, and it has good physical meanings

Short-Term Reliability Evaluation of Transmission System Using Lightning Strike Probability Prediction

The transmission lines are exposed to the atmosphere nature and will be affected by adverse weather such as lightning storm, so that it will affect the reliability of transmission system. This paper studies the fault probability model of transmission line during the lightning storm, and evaluates the short-term reliability of transmission system in the forecasting weather condition. Firstly, build the lightning strike fault probability model of the transmission line based on historical lightning record information, then calculate the lightning strike probability under the forecasting weather conditions, furthermore evaluate the reliability index of transmission system. Utilizing IEEE RTS-79 system to verify the validity of the proposed model and the results show that lightning has great negative influence on the transmission lines and the reliability of transmission system. The reliability evaluation model proposed in this paper can guide the short-term operation and online scheduling for transmission system operators.