This paper proposes a new non-intrusive hybrid interval method using derivative information for the dynamic response analysis of nonlinear systems with uncertain-but- bounded parameters and/or initial conditions. This...This paper proposes a new non-intrusive hybrid interval method using derivative information for the dynamic response analysis of nonlinear systems with uncertain-but- bounded parameters and/or initial conditions. This method provides tighter solution ranges compared to the existing polynomial approximation interval methods. Interval arith- metic using the Chebyshev basis and interval arithmetic using the general form modified affine basis for polynomials are developed to obtain tighter bounds for interval computation. To further reduce the overestimation caused by the ＂wrap- ping effect＂ of interval arithmetic, the derivative information of dynamic responses is used to achieve exact solutions when the dynamic responses are monotonic with respect to all the uncertain variables. Finally, two typical numerical examples with nonlinearity are applied to demonstrate the effective- ness of the proposed hybrid interval method, in particular, its ability to effectively control the overestimation for specific timepoints.展开更多
In this paper, a novel hybrid method is presented for finding global optimization of an objective function. Based on the interval computation, this hybrid method combines interval deterministic method and stochastic e...In this paper, a novel hybrid method is presented for finding global optimization of an objective function. Based on the interval computation, this hybrid method combines interval deterministic method and stochastic evolution method. It can find global optimization quickly while ensuring the deterministic and stability of the algorithm. When using interval computation, extra width constraints accuracy of interval computation results. In this paper, a splitting method to reduce the extra width is introduced. This method is easy and it can get a more precise interval computation result. When finding the global optimization, it can increase the efficiency of pruning. Several experiments are given to illustrate the advantage of the new hybrid method.展开更多
随着大量新能源场站接入交直流混联电网,系统的静态电压稳定裕度(static voltage stability margin,SVSM)水平具有很大的不确定性,需要研究考虑新能源场站高阶不确定性的交直流混联电网SVSM计算方法。针对此问题,首先建立了交直流混联电...随着大量新能源场站接入交直流混联电网,系统的静态电压稳定裕度(static voltage stability margin,SVSM)水平具有很大的不确定性,需要研究考虑新能源场站高阶不确定性的交直流混联电网SVSM计算方法。针对此问题,首先建立了交直流混联电网SVSM计算模型,模型中考虑了直流换流站控制方式随负荷增长的切换;采用概率盒模型描述风速与光照强度的随机波动,提出了改进区间半不变量法以获得更准确的SVSM概率盒,该方法通过K-means++聚类算法将随机变量样本划分为多个波动范围较小的样本集,以降低半不变量的线性化计算带来的误差;并结合Gram-Charlier级数展开和概率加权和计算得到考虑新能源场站高阶不确定性的系统SVSM概率盒。通过对修改的IEEE-39节点交直流系统和南方电网两个算例的分析,并与区间半不变量法和双层蒙特卡洛法比较,验证了所提出方法获得的SVSM概率盒具有较高的计算精度和效率。展开更多
Statistical inference is developed for the analysis of generalized type-Ⅱ hybrid censoring data under exponential competing risks model. In order to solve the problem that approximate methods make unsatisfactory perf...Statistical inference is developed for the analysis of generalized type-Ⅱ hybrid censoring data under exponential competing risks model. In order to solve the problem that approximate methods make unsatisfactory performances in the case of small sample size,we establish the exact conditional distributions of estimators for parameters by conditional moment generating function(CMGF). Furthermore, confidence intervals(CIs) are constructed by exact distributions, approximate distributions as well as bootstrap method respectively,and their performances are evaluated by Monte Carlo simulations. And finally, a real data set is analyzed to illustrate all the methods developed here.展开更多
从智能效益、经济效益、绿色效益和安全效益4个维度构建了智能变电站建设项目综合效益评价指标体系。其中评价指标的属性值为包含语言变量、精确数和正态分布区间数的混合信息。在此基础上,基于直觉模糊集和组合赋权法,构建了一种面向...从智能效益、经济效益、绿色效益和安全效益4个维度构建了智能变电站建设项目综合效益评价指标体系。其中评价指标的属性值为包含语言变量、精确数和正态分布区间数的混合信息。在此基础上,基于直觉模糊集和组合赋权法,构建了一种面向混合信息的混合多准则决策模型。该模型首先用不同的转换规则将混合信息一致化为直觉模糊数的形式。然后采用基于合作博弈模型的群组决策特征根法-直觉模糊熵(group eigenvalue method intuitionistic fuzzy entropy,GEM-IFE)组合赋权法来确定指标的综合权重,并基于直觉模糊集建立了改进的逼近理想解排序方法(technique for order preference by similarity to ideal solution,TOPSIS)评价模型。最后,以10个智能变电站建设项目作为案例进行分析,并将该模型与传统的TOPSIS方法和单一赋权法进行比较。结果证明该混合多准则决策模型具有良好的鲁棒性。展开更多
This paper presents a hybrid model reliability analysis method based on the damped Newton method with both random and interval variables to solve the hybrid structure reliability problem.The method combines an outer i...This paper presents a hybrid model reliability analysis method based on the damped Newton method with both random and interval variables to solve the hybrid structure reliability problem.The method combines an outer iterative solution and inner layer numerical calculation.In the outer iteration,the method seeks an optimized solution to the interval variable iterative by adding the boundary constraint condition based on the damped Newton optimization theory.In the inner layer solution,the method first reduces the dimension of the random variable through the dimension reduction method,then obtains the first four-order central moment of the function through the application of the Taylor expansion method,and finally calculates the reliability index of the structure according to the fourth-order moment calculation structure of the function.The results of a numerical example and an engineering ten-rod truss structure show that the proposed method can effectively solve the random-interval hybrid reliability problem and has better calculation accuracy than that of the two-layer iterative method.展开更多
文摘This paper proposes a new non-intrusive hybrid interval method using derivative information for the dynamic response analysis of nonlinear systems with uncertain-but- bounded parameters and/or initial conditions. This method provides tighter solution ranges compared to the existing polynomial approximation interval methods. Interval arith- metic using the Chebyshev basis and interval arithmetic using the general form modified affine basis for polynomials are developed to obtain tighter bounds for interval computation. To further reduce the overestimation caused by the ＂wrap- ping effect＂ of interval arithmetic, the derivative information of dynamic responses is used to achieve exact solutions when the dynamic responses are monotonic with respect to all the uncertain variables. Finally, two typical numerical examples with nonlinearity are applied to demonstrate the effective- ness of the proposed hybrid interval method, in particular, its ability to effectively control the overestimation for specific timepoints.
基金Project supported by the Natural High-Technology Research and Development Program of China(Grant No.2009AA012201)the Major Technology Research and Development Program of Shanghai Municipality(Grant No.08DZ501600)the Shanghai Leading Academic Discipline Project(Grant No.J50103)
文摘In this paper, a novel hybrid method is presented for finding global optimization of an objective function. Based on the interval computation, this hybrid method combines interval deterministic method and stochastic evolution method. It can find global optimization quickly while ensuring the deterministic and stability of the algorithm. When using interval computation, extra width constraints accuracy of interval computation results. In this paper, a splitting method to reduce the extra width is introduced. This method is easy and it can get a more precise interval computation result. When finding the global optimization, it can increase the efficiency of pruning. Several experiments are given to illustrate the advantage of the new hybrid method.
文摘随着大量新能源场站接入交直流混联电网,系统的静态电压稳定裕度(static voltage stability margin,SVSM)水平具有很大的不确定性,需要研究考虑新能源场站高阶不确定性的交直流混联电网SVSM计算方法。针对此问题,首先建立了交直流混联电网SVSM计算模型,模型中考虑了直流换流站控制方式随负荷增长的切换;采用概率盒模型描述风速与光照强度的随机波动,提出了改进区间半不变量法以获得更准确的SVSM概率盒,该方法通过K-means++聚类算法将随机变量样本划分为多个波动范围较小的样本集,以降低半不变量的线性化计算带来的误差;并结合Gram-Charlier级数展开和概率加权和计算得到考虑新能源场站高阶不确定性的系统SVSM概率盒。通过对修改的IEEE-39节点交直流系统和南方电网两个算例的分析,并与区间半不变量法和双层蒙特卡洛法比较,验证了所提出方法获得的SVSM概率盒具有较高的计算精度和效率。
基金Supported by the National Natural Science Foundation of China（71401134, 71571144, 71171164） Supported by the Natural Science Basic Research Program of Shaanxi Province（2015JM1003）+1 种基金 Sup- ported by the Program of International Cooperation and Exchanges in Science and Technology Funded of Shaanxi Province（2016KW-033） Supported by the Scholarship Program of Shanxi Province（2016-015）
文摘Statistical inference is developed for the analysis of generalized type-Ⅱ hybrid censoring data under exponential competing risks model. In order to solve the problem that approximate methods make unsatisfactory performances in the case of small sample size,we establish the exact conditional distributions of estimators for parameters by conditional moment generating function(CMGF). Furthermore, confidence intervals(CIs) are constructed by exact distributions, approximate distributions as well as bootstrap method respectively,and their performances are evaluated by Monte Carlo simulations. And finally, a real data set is analyzed to illustrate all the methods developed here.
文摘从智能效益、经济效益、绿色效益和安全效益4个维度构建了智能变电站建设项目综合效益评价指标体系。其中评价指标的属性值为包含语言变量、精确数和正态分布区间数的混合信息。在此基础上,基于直觉模糊集和组合赋权法,构建了一种面向混合信息的混合多准则决策模型。该模型首先用不同的转换规则将混合信息一致化为直觉模糊数的形式。然后采用基于合作博弈模型的群组决策特征根法-直觉模糊熵(group eigenvalue method intuitionistic fuzzy entropy,GEM-IFE)组合赋权法来确定指标的综合权重,并基于直觉模糊集建立了改进的逼近理想解排序方法(technique for order preference by similarity to ideal solution,TOPSIS)评价模型。最后,以10个智能变电站建设项目作为案例进行分析,并将该模型与传统的TOPSIS方法和单一赋权法进行比较。结果证明该混合多准则决策模型具有良好的鲁棒性。
基金supported by the National Natural Science Foundation of China(No.51775230)。
文摘This paper presents a hybrid model reliability analysis method based on the damped Newton method with both random and interval variables to solve the hybrid structure reliability problem.The method combines an outer iterative solution and inner layer numerical calculation.In the outer iteration,the method seeks an optimized solution to the interval variable iterative by adding the boundary constraint condition based on the damped Newton optimization theory.In the inner layer solution,the method first reduces the dimension of the random variable through the dimension reduction method,then obtains the first four-order central moment of the function through the application of the Taylor expansion method,and finally calculates the reliability index of the structure according to the fourth-order moment calculation structure of the function.The results of a numerical example and an engineering ten-rod truss structure show that the proposed method can effectively solve the random-interval hybrid reliability problem and has better calculation accuracy than that of the two-layer iterative method.
