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Planning failure-censored constant-stress partially accelerated life test

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Journal of Systems Engineering and Electronics 2015年第3期26卷 644-650页

作者： Ali A.Ismail Abdulhakim A.Al-Babtain Department of Statistics and Operations Research College of Science King Saud University Department of Statistics Faculty of Economics & Political Science Cairo University

This article deals with the case of the failure-censored constant-stress partially accelerated life test （CSPALT） for highly reliable materials or products assuming the Pareto distribution of the second kind. The maximum likelihood （ML） method is used to estimate the parameters of the CSPALT model. The performance of ML estimators is investigated via their mean square error. Also, the average confidence interval length （IL） and the associated co- verage probability （CP） are obtained. Moreover, optimum CSPALT plans that determine the optimal proportion of the test units al- located to each stress are developed. Such optimum test plans minimize the generalized asymptotic variance （GAV） of the ML estimators of the model parameters. For illustration, monte carlo simulation.studies are given and a real life example is provided.

关键词： reliability confidence intervals coverage probabilities,optimum test plans Type-Ⅱ censoring monte carlo simulation.

Dynamics of Polypropylene Chains in Their Binary Blends of Different Stereochemical Sequences Studied by monte carlo simulation.

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Chinese Journal of Polymer Science 2014年第5期32卷 640-650页

作者： Tanissara Pinijmontree Visit Vao-soongnern Laboratory of Computational and Applied Polymer Science (LCAPS) School of Chemistry Institute of Science Suranaree University of Technology

The conformational and dynamic properties of polypropylene （PP） for both pure melts and blends with different chain tacticity were investigated by monte carlo simulation.of isotactic （iPP）, atactic （aPP） and syndiotactic （sPP） polypropylenes. The simulation.of coarse-grained PP models was performed on a high coordination lattice incorporating short- and long-range intramolecular interactions from the rotational isomeric state （RIS） model and Lennard-Jones （LJ） potential function of propane pairs, respectively. The dynamics of chains in binary PP/PP mixture were investigated with the composition of C150H302 with different chain taciticity. The diffusion rates of PP with different stereochemistry are generally in the order as： iPP 〉 aPP 〉〉 sPP. For PP/PP blends with 50：50 wt% binary mixtures, immiscibility was observed when sPP was introduced into the mixtures. The diffusion rate of iPP and aPP became slower after mixing, while sPP diffuses significantly faster in the binary mixtures. The mobility of PP chains depends on both intramolecular （molecular size and chain stiffness） and intermolecular （chain packing） interactions. The effect of intramolecular contribution is greater than that of intermolecular contribution for iPP and aPP chains in binary mixtures. For sPP chain, intermolecular interaction has greater influence on the dynamics than intramolecular contribution.

关键词： Binary blends of PP with different stereochemical sequences Dynamics Tacticity effect monte carlo simulation.

Cost consequence-based reliability analysis of bursting and buckling failure modes in subsea pipelines

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Journal of Ocean Engineering and Science 2019年第1期4卷 64-76页

作者： Bahram Mehrafrooz Pedram Edalat Mojtaba Dyanati Offshore Structural Engineering Department Petroleum University of TechnologyMazandaranIran The University of Akron United States

Risk assessment is a fundamental activity to evaluate the integrity of pipeline systems during their life cycle,which allows pipeline operators to focus attention on integrity management activities in order to prevent and mitigate failure and maintain the design safety *** for materials and contractor’s quality are a major source of concern about the integrity of pipelines and have a remarkable influence on the optimized balance between capital expenditure(CAPEX)and operation expenses(OPEX)in risk-based integrity management of *** other sources of risks to pipelines have been investigated thoroughly,the impacts of construction and material quality have not been well studied *** paper addresses the influence of construction accuracy/quality and corresponding uncertainties on the failure of submarine pipelines in the presence of ***-bursting and corrosion-buckling failure modes(which are addressed as ultimate limit states of subsea pipeline in DNV-OS-F101)are investigated in a reliability analysis to predict critical failure year of the *** analysis is also implemented to estimate the importance of parameters on failure probability using monte carlo simulation.MCS).The results show a high sensitivity of failure probability to construction accuracy,which defines contractor quality.

关键词： Subsea pipeline Bursting Buckling Construction quality Reliability monte carlo simulation.

A new generalized version of Log-logistic distribution with applications in medical sciences and other applied fields

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International Journal of Modeling, simulation. and Scientific Computing 2018年第5期9卷 140-161页

作者： Bilal Ahmad Para Tariq Rashid Jan Department of Statistics University of Kashmir Srinagar Jammu and KashmirIndia

In this paper,we studied a two-parameter transmuted model of Log-logistic distribution(LLD)using the quadratic rank transmutation map technique studied by Shaw and Buckley1 as a new survival model in medical sciences and other applied *** properties of Transmuted LLD(TLLD)are discussed *** measures of skewness and kurtosis of the proposed model have also been discussed along with graphical *** estimation of the model parameters is performed by Maximum Likelihood(ML)method followed by a monte carlo(MC)simulation.procedure to investigate the performance of the ML estimators and the asymptotic confidence intervals of the *** of the proposed model to real-life data are also presented.

关键词： Transmuted Log-logistic distribution(TLLD) survival analysis lifetime medical sciences monte carlo simulation.

AN INEXACT LAGRANGE-NEWTON METHOD FOR STOCHASTIC QUADRATIC PROGRAMS WITH RECOURSE

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Applied Mathematics(A Journal of Chinese Universities) 2004年第2期19卷 229-238页

作者： ZhouChangyin HeGuoping Dept.ofMath. ShanghaiJiaotongUniv.Shanghai200240China CollegeofInformationScienceandEngineering ShandongUniversityofScienceandTechnologyTaian271019China

In this paper,two-stage stochastic quadratic programming problems with equality constraints are *** monte carlo simulation.based approximations of the objective function and its first(second)derivative,an inexact Lagrange-Newton type method is *** is showed that this method is globally convergent with probability *** particular,the convergence is local superlinear under an integral approximation error bound ***,this method can be easily extended to solve stochastic quadratic programming problems with inequality constraints.

关键词： Lagrange-Newton method stochastic quadratic programming monte carlo simulation.

Influence of absorption in linear polarization imaging of melanoma tissues

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Journal of Innovative Optical Health Sciences 2014年第3期7卷 59-66页

作者： Dongzhi Li Honghui He Nan Zeng Weidong Xie Ran Liao Jian Wu Yonghong He Hui Ma Shenzhen Key Laboratory for Minimal Invasive Medical Technologies Graduate School at Shenzhen Tsinghua UniversityShenzhen 518055P.R.China Department of Physics Tsinghua University Beijing 100084P.R.Chinat

The contrast mechanism of different polarization imaging techniques for melanoma in mouse skin is st udied using both experiments and monte carlo *** intensity,linear polariz-ation diference imaging(DPI),degree of polarization imaging(DOPI)and'rotating linearpolarization imaging(RLPl)are applied and the relative contrasts of these polarization imagingmethods between the normal and cancerous tissues are compared.A two-layer absorption-scat-tering model is proposed to explain the contrast mechanism of the polarization imaging *** taking into account of both scattering of symmetrical and asymmetrical scat terersand absorption of inter-scatterer medium,the two-layer model reproduces the relative con trastsfor polarization images observed in *** simulation.results also show that,theparameters of polarization imaging change more dramatically with the variation of absorption inthe bottom layer than the top layer.

关键词： Polarization imaging melanoma two-layer model monte carlo simulation.

AN INFERENCE STUDY ON THE PROCESS CAPABILLITY INDEX FOR NON-NORMAL DATA BASED ON MODIFIED WEIGHTED VARIANCE

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AN INFERENCE STUDY ON THE PROCESS CAPABILLITY INDEX FOR NON-...