We propose a class of iteration methods searching the best approximately generalized polynomial, which has parallel computational function and converges to the exact solution quadratically. We first transform it into ...We propose a class of iteration methods searching the best approximately generalized polynomial, which has parallel computational function and converges to the exact solution quadratically. We first transform it into a special system of nonlinear equations with constraint, then by using to certain iteration method, we combine the two basic processes of the Remes method into a whole such that the iterative process of the system of nonlinear equations and the computation of the solution to the system of linear equations proceed alternately. A lot of numerical examples show that this method not only has good convergence property but also always converges to the exact solution of the problem accurately and rapidly for almost all initial approximations .展开更多
Heavy-duty machine tools are composed of many subsystems with different functions,and their reliability is governed by the reliabilities of these subsystems.It is important to rank the weaknesses of subsystems and ide...Heavy-duty machine tools are composed of many subsystems with different functions,and their reliability is governed by the reliabilities of these subsystems.It is important to rank the weaknesses of subsystems and identify the weakest subsystem to optimize products and improve their reliabilities.However,traditional ranking methods based on failure mode effect and critical analysis(FMECA)does not consider the complex maintenance of products.Herein,a weakness ranking method for the subsystems of heavy-duty machine tools is proposed based on generalized FMECA information.In this method,eight reliability indexes,including maintainability and maintenance cost,are considered in the generalized FMECA information.Subsequently,the cognition best worst method is used to calculate the weight of each screened index,and the weaknesses of the subsystems are ranked using a technique for order preference by similarity to an ideal solution.Finally,based on the failure data collected from certain domestic heavy-duty horizontal lathes,the weakness ranking result of the subsystems is obtained to verify the effectiveness of the proposed method.An improved weakness ranking method that can comprehensively analyze and identify weak subsystems is proposed herein for designing and improving the reliability of complex electromechanical products.展开更多
为了准确判断施工现场在突降暴雨情况下的安全状态,采用贝叶斯最优最劣法(Bayesian Best Worst Method,BBWM)和云模型方法,提出暴雨灾害下的建筑施工现场风险评价模型,以确定施工现场在遭受暴雨灾害时的风险等级。该模型利用了压力状态...为了准确判断施工现场在突降暴雨情况下的安全状态,采用贝叶斯最优最劣法(Bayesian Best Worst Method,BBWM)和云模型方法,提出暴雨灾害下的建筑施工现场风险评价模型,以确定施工现场在遭受暴雨灾害时的风险等级。该模型利用了压力状态响应模型(Pressure State Response,PSR)和灾害系统理论,在考虑致灾因子危险性、孕灾环境稳定性、承灾体脆弱性和减灾能力抵御性4方面的基础上,构建18个风险因素的施工现场风险评价指标体系,并以武汉市某施工现场为例进行验证。结果显示,施工现场的减灾能力抵御性处于最重要的地位,做好现场减灾应对措施对灾害有非常重要的帮助;案例项目的评价结果处于一般风险状态,与现场实际情况相符。展开更多
文摘We propose a class of iteration methods searching the best approximately generalized polynomial, which has parallel computational function and converges to the exact solution quadratically. We first transform it into a special system of nonlinear equations with constraint, then by using to certain iteration method, we combine the two basic processes of the Remes method into a whole such that the iterative process of the system of nonlinear equations and the computation of the solution to the system of linear equations proceed alternately. A lot of numerical examples show that this method not only has good convergence property but also always converges to the exact solution of the problem accurately and rapidly for almost all initial approximations .
基金Supported by National Nat ural Science Foundation of China(Grant Nos.51675227,51975249)Jilin Province Science and Technology Development Funds(Grant Nos.20180201007GX,20190302017GX)+2 种基金Technology Development and Research of Jilin Province(Grant No.2019C037-01)Changchun Science and Technology Planning Project(Grant No.19SS011)National Science and technology Major Project(Grant No.2014ZX04015031).
文摘Heavy-duty machine tools are composed of many subsystems with different functions,and their reliability is governed by the reliabilities of these subsystems.It is important to rank the weaknesses of subsystems and identify the weakest subsystem to optimize products and improve their reliabilities.However,traditional ranking methods based on failure mode effect and critical analysis(FMECA)does not consider the complex maintenance of products.Herein,a weakness ranking method for the subsystems of heavy-duty machine tools is proposed based on generalized FMECA information.In this method,eight reliability indexes,including maintainability and maintenance cost,are considered in the generalized FMECA information.Subsequently,the cognition best worst method is used to calculate the weight of each screened index,and the weaknesses of the subsystems are ranked using a technique for order preference by similarity to an ideal solution.Finally,based on the failure data collected from certain domestic heavy-duty horizontal lathes,the weakness ranking result of the subsystems is obtained to verify the effectiveness of the proposed method.An improved weakness ranking method that can comprehensively analyze and identify weak subsystems is proposed herein for designing and improving the reliability of complex electromechanical products.
文摘为了准确判断施工现场在突降暴雨情况下的安全状态,采用贝叶斯最优最劣法(Bayesian Best Worst Method,BBWM)和云模型方法,提出暴雨灾害下的建筑施工现场风险评价模型,以确定施工现场在遭受暴雨灾害时的风险等级。该模型利用了压力状态响应模型(Pressure State Response,PSR)和灾害系统理论,在考虑致灾因子危险性、孕灾环境稳定性、承灾体脆弱性和减灾能力抵御性4方面的基础上,构建18个风险因素的施工现场风险评价指标体系,并以武汉市某施工现场为例进行验证。结果显示,施工现场的减灾能力抵御性处于最重要的地位,做好现场减灾应对措施对灾害有非常重要的帮助;案例项目的评价结果处于一般风险状态,与现场实际情况相符。
文摘为针对性地解决转炉炼钢作业时的消防安全问题,提出将熵权-最优最劣法(Best Worst Method,BWM)和物元可拓模型相结合的转炉车间火灾风险评估模型。通过将指标分为人、物料设备、环境、管理及消防设施5大类,构建转炉车间火灾风险评估指标体系;利用复合语言对35个指标进行评价,引入有序加权平均算子(Ordered Weighted Averaging,OWA)计算各语言的犹豫语言术语集(Hesitant Fuzzy Linguistic Term Set,HFLTS)模糊包络,再根据各专家权重进行加权计算并将语言量化构成评价矩阵;基于熵权、BWM分别算得各指标权重,再运用最小二乘法得到综合权重;最后利用物元可拓模型确定各指标及转炉车间的火灾风险等级。以河北省某炼钢转炉车间为例进行评估得出:该转炉车间的综合风险等级为I级(安全),其中动火监护的人员监管情况、氧枪法兰松紧度、炉前温度环境、作业现场物品摆放情况、作业巡查及设备检查情况和消防疏散通道堵塞情况仍需改善。
