Due to the randomness and time dependence of the factors affecting software reliability, most software reliability models are treated as stochastic processes, and the non-homogeneous Poisson process(NHPP) is the most ...Due to the randomness and time dependence of the factors affecting software reliability, most software reliability models are treated as stochastic processes, and the non-homogeneous Poisson process(NHPP) is the most used one.However, the failure behavior of software does not follow the NHPP in a statistically rigorous manner, and the pure random method might be not enough to describe the software failure behavior. To solve these problems, this paper proposes a new integrated approach that combines stochastic process and grey system theory to describe the failure behavior of software. A grey NHPP software reliability model is put forward in a discrete form, and a grey-based approach for estimating software reliability under the NHPP is proposed as a nonlinear multi-objective programming problem. Finally, four grey NHPP software reliability models are applied to four real datasets, the dynamic R-square and predictive relative error are calculated. Comparing with the original single NHPP software reliability model, it is found that the modeling using the integrated approach has a higher prediction accuracy of software reliability. Therefore, there is the characteristics of grey uncertain information in the NHPP software reliability models, and exploiting the latent grey uncertain information might lead to more accurate software reliability estimation.展开更多
The reliability-based selective maintenance(RSM)decision problem of systems with components that have multiple dependent performance characteristics(PCs)reflecting degradation states is addressed in this paper.A vine-...The reliability-based selective maintenance(RSM)decision problem of systems with components that have multiple dependent performance characteristics(PCs)reflecting degradation states is addressed in this paper.A vine-Copulabased reliability evaluation method is proposed to estimate the reliability of system components with multiple PCs.Specifically,the marginal degradation reliability of each PC is built by using the Wiener stochastic process based on the PC’s degradation mechanism.The joint degradation reliability of the component with multiple PCs is established by connecting the marginal reliability of PCs using D-vine.In addition,two RSM decision models are developed to ensure the system accomplishes the next mission.The genetic algorithm(GA)is used to solve the constraint optimization problem of the models.A numerical example illustrates the application of the proposed RSM method.展开更多
Aiming to evaluate the reliability of phase-transition degrading systems,a generalized stochastic degradation model with phase transition is constructed,and the corresponding analytical reliability function is formula...Aiming to evaluate the reliability of phase-transition degrading systems,a generalized stochastic degradation model with phase transition is constructed,and the corresponding analytical reliability function is formulated under the concept of the first hitting time.The phase-varying stochastic property and the phase-varying nonlinearity are considered simultaneously in the proposed model.To capture the phase-varying stochastic pro-perty,a Wiener process is adopted to model the non-monotonous degradation phase,while a Gamma process is utilized to model the monotonous one.In addition,the phase-varying non-linearity is captured by different transformed time scale functions.To facilitate the practical application of the proposed model,identification of phase model type and estimation of model parameters are discussed,and the initial guesses for parameters optimization are also given.Based on the constructed model,two simulation studies are carried out to verify the analytical reliability function and analyze the influence of model misspecification.Finally,a practical case study is conducted for illustration.展开更多
To degrade location accuracy for unauthorized GPS users, US government applied Selective Availability (SA) to Global Positioning System (GPS). In this paper we discuss an anti-SAapproach to improve location accuracy w...To degrade location accuracy for unauthorized GPS users, US government applied Selective Availability (SA) to Global Positioning System (GPS). In this paper we discuss an anti-SAapproach to improve location accuracy which is very important in landing position, and then we derived the SA error by eliminating almost all other errors including ionospheric and tropospheric timedelays and clock errors both in satellites and in receiver, etc. By means of the system identificationtheory, an SA errorl all SA error model with the second-order Gauss-Maukov stochastic process wasderived and simulated. With the selected parameters of the stochastic process) the simulation resultsshow that there is the excellent agreement between the simulated SA error model and that of reallyapplied in GPS system.展开更多
We propose here a mathematical approach for the study of repairable systems with arbitrary distributions. The idea is to define a new type of stochastic process, called a generalized Markov renewal process (GMRP). whi...We propose here a mathematical approach for the study of repairable systems with arbitrary distributions. The idea is to define a new type of stochastic process, called a generalized Markov renewal process (GMRP). which may describe the transition behavior of the stochastic process at non-regenerative points. In the paper an analytical method for the GMRP is put forward and the formulas are then presented for reliability analysis of repairable systems which can be described by a GMRP with finite states. A signal flow graph technique for system modeling is also summarized here. Finally- an analytical model to evaluate the reliability of a m-out-of- n.G system with general repair-time distribution is developed by means of the GMRP approach.展开更多
基金supported by the National Natural Science Foundation of China (71671090)the Fundamental Research Funds for the Central Universities (NP2020022)the Qinglan Project of Excellent Youth or Middle-Aged Academic Leaders in Jiangsu Province。
文摘Due to the randomness and time dependence of the factors affecting software reliability, most software reliability models are treated as stochastic processes, and the non-homogeneous Poisson process(NHPP) is the most used one.However, the failure behavior of software does not follow the NHPP in a statistically rigorous manner, and the pure random method might be not enough to describe the software failure behavior. To solve these problems, this paper proposes a new integrated approach that combines stochastic process and grey system theory to describe the failure behavior of software. A grey NHPP software reliability model is put forward in a discrete form, and a grey-based approach for estimating software reliability under the NHPP is proposed as a nonlinear multi-objective programming problem. Finally, four grey NHPP software reliability models are applied to four real datasets, the dynamic R-square and predictive relative error are calculated. Comparing with the original single NHPP software reliability model, it is found that the modeling using the integrated approach has a higher prediction accuracy of software reliability. Therefore, there is the characteristics of grey uncertain information in the NHPP software reliability models, and exploiting the latent grey uncertain information might lead to more accurate software reliability estimation.
基金supported by the Aeronautical Science Foundation of China(20150863003).
文摘The reliability-based selective maintenance(RSM)decision problem of systems with components that have multiple dependent performance characteristics(PCs)reflecting degradation states is addressed in this paper.A vine-Copulabased reliability evaluation method is proposed to estimate the reliability of system components with multiple PCs.Specifically,the marginal degradation reliability of each PC is built by using the Wiener stochastic process based on the PC’s degradation mechanism.The joint degradation reliability of the component with multiple PCs is established by connecting the marginal reliability of PCs using D-vine.In addition,two RSM decision models are developed to ensure the system accomplishes the next mission.The genetic algorithm(GA)is used to solve the constraint optimization problem of the models.A numerical example illustrates the application of the proposed RSM method.
基金This work was supported by the National Natural Science Foundation of China(11872085)the National Key Research and Development Program of China(2018YFF0216004).
文摘Aiming to evaluate the reliability of phase-transition degrading systems,a generalized stochastic degradation model with phase transition is constructed,and the corresponding analytical reliability function is formulated under the concept of the first hitting time.The phase-varying stochastic property and the phase-varying nonlinearity are considered simultaneously in the proposed model.To capture the phase-varying stochastic pro-perty,a Wiener process is adopted to model the non-monotonous degradation phase,while a Gamma process is utilized to model the monotonous one.In addition,the phase-varying non-linearity is captured by different transformed time scale functions.To facilitate the practical application of the proposed model,identification of phase model type and estimation of model parameters are discussed,and the initial guesses for parameters optimization are also given.Based on the constructed model,two simulation studies are carried out to verify the analytical reliability function and analyze the influence of model misspecification.Finally,a practical case study is conducted for illustration.
文摘To degrade location accuracy for unauthorized GPS users, US government applied Selective Availability (SA) to Global Positioning System (GPS). In this paper we discuss an anti-SAapproach to improve location accuracy which is very important in landing position, and then we derived the SA error by eliminating almost all other errors including ionospheric and tropospheric timedelays and clock errors both in satellites and in receiver, etc. By means of the system identificationtheory, an SA errorl all SA error model with the second-order Gauss-Maukov stochastic process wasderived and simulated. With the selected parameters of the stochastic process) the simulation resultsshow that there is the excellent agreement between the simulated SA error model and that of reallyapplied in GPS system.
文摘We propose here a mathematical approach for the study of repairable systems with arbitrary distributions. The idea is to define a new type of stochastic process, called a generalized Markov renewal process (GMRP). which may describe the transition behavior of the stochastic process at non-regenerative points. In the paper an analytical method for the GMRP is put forward and the formulas are then presented for reliability analysis of repairable systems which can be described by a GMRP with finite states. A signal flow graph technique for system modeling is also summarized here. Finally- an analytical model to evaluate the reliability of a m-out-of- n.G system with general repair-time distribution is developed by means of the GMRP approach.
