In this paper, a new class of three term memory gradient method with non-monotone line search technique for unconstrained optimization is presented. Global convergence properties of the new methods are discussed. Comb...In this paper, a new class of three term memory gradient method with non-monotone line search technique for unconstrained optimization is presented. Global convergence properties of the new methods are discussed. Combining the quasi-Newton method with the new method, the former is modified to have global convergence property. Numerical results show that the new algorithm is efficient.展开更多
In this paper, we propose and analyze a non-monotone trust region method with non-monotone line search strategy for unconstrained optimization problems. Unlike the traditional non-monotone trust region method, our alg...In this paper, we propose and analyze a non-monotone trust region method with non-monotone line search strategy for unconstrained optimization problems. Unlike the traditional non-monotone trust region method, our algorithm utilizes non-monotone Wolfe line search to get the next point if a trial step is not adopted. Thus, it can reduce the number of solving sub-problems. Theoretical analysis shows that the new proposed method has a global convergence under some mild conditions.展开更多
A one-dimensional monotone interpolation method based on interface reconstruction with partial volumes in the slope-space utilizing the Hermite cubic-spline, is proposed. The new method is only quartic, however is C2 ...A one-dimensional monotone interpolation method based on interface reconstruction with partial volumes in the slope-space utilizing the Hermite cubic-spline, is proposed. The new method is only quartic, however is C2 and unconditionally monotone. A set of control points is employed to constrain the curvature of the interpolation function and to eliminate possible nonphysical oscillations in the slope space. An extension of this method in two-dimensions is also discussed.展开更多
The existence, uniqueness and non-symmetric iterative approximation of solutions for a class of systems of mixed monotone operator equations are discussed. As an application, we utilize, the results presented in this ...The existence, uniqueness and non-symmetric iterative approximation of solutions for a class of systems of mixed monotone operator equations are discussed. As an application, we utilize, the results presented in this paper to study the existence and uniqueness problems of common solutions for a class of systems of functional equations arising in dynamic programming of multistage decision processes and a class of systems of nonlinear integral equation. The results obtained in this paper not only answer an open question suggested in [3] but also generalize the corresponding results of [1],[2].展开更多
A new computation scheme proposed to tackle commensurate problems is devel- oped by modifying the semi-analytic approach for minimizing computational complexity. Using the proposed scheme, the limit state equations, u...A new computation scheme proposed to tackle commensurate problems is devel- oped by modifying the semi-analytic approach for minimizing computational complexity. Using the proposed scheme, the limit state equations, usually referred to as the failure surface, are obtained from transformation of an interval variable to a normalized one. In order to minimize the computational cost, two algorithms for optimizing the calculation steps have been proposed. The monotonicity of the objective function can be determined from narrowing the scope of interval variables in normalized infinite space by incorporating the algorithms into the computational scheme. Two examples are used to illustrate the operation and computational efficiency of the approach. The results of these examples show that the proposed algorithms can greatly reduce the computation complexity without sacrificing the computational accuracy. The advantage of the proposed scheme can be even more efficient for analyzing sophistic structures.展开更多
Minimal cut sets （or prime implicants： minimal combinations of basic event conditions leading to system failure） are important information for reliability/safety analysis and design. To obtain minimal cut sets for ...Minimal cut sets （or prime implicants： minimal combinations of basic event conditions leading to system failure） are important information for reliability/safety analysis and design. To obtain minimal cut sets for general non-coherent fault trees, including negative basic events or multi-valued basic events, a special procedure such as the consensus rule must be applied to the results obtained by logical operations for coherent fault trees, which will require more steps and time. This paper proposes a simple method for a non-coherent fault tree, whose top event is represented as an AND combination of monotonic sub-trees. A ＂monotonic＂ sub-tree means that it does not have both positive and negative representations for each basic event. It is proven that minimal cut sets can be obtained by a conventional method for coherent fault trees. An illustrative example of a simple event tree analysis shows the detail and characteristics of the proposed method.展开更多
Many approaches have been put forward to resolve the variational inequality problem. The subgradient extragradient method is one of the most effective. This paper proposes a modified subgradient extragradient method a...Many approaches have been put forward to resolve the variational inequality problem. The subgradient extragradient method is one of the most effective. This paper proposes a modified subgradient extragradient method about classical variational inequality in a real Hilbert interspace. By analyzing the operator’s partial message, the proposed method designs a non-monotonic step length strategy which requires no line search and is independent of the value of Lipschitz constant, and is extended to solve the problem of pseudomonotone variational inequality. Meanwhile, the method requires merely one map value and a projective transformation to the practicable set at every iteration. In addition, without knowing the Lipschitz constant for interrelated mapping, weak convergence is given and R-linear convergence rate is established concerning algorithm. Several numerical results further illustrate that the method is superior to other algorithms.展开更多
我国首个海上风电柔性直流送出工程(如东工程)投运初期,在风电场与柔直海上换流站之间出现了320Hz的中频振荡现象,造成柔直系统高频谐波保护动作跳闸。为揭示海上风电柔直送出系统的中频振荡机理及特性,首先,建立了考虑风电机组控制、...我国首个海上风电柔性直流送出工程(如东工程)投运初期,在风电场与柔直海上换流站之间出现了320Hz的中频振荡现象,造成柔直系统高频谐波保护动作跳闸。为揭示海上风电柔直送出系统的中频振荡机理及特性,首先,建立了考虑风电机组控制、柔直海上换流器控制、延时环节和交流输电海缆等的海上风电柔直送出系统小信号状态空间模型。然后,从柔直海上换流器内部参数交互、风电场内部参数交互、风电场与柔直海上换流器间参数交互三方面,利用特征值分析法分析了中频振荡的特性及主要影响因素。研究表明,在控制延时的作用下,柔直海上换流器的电流内环、风电机组网侧换流器的电流内环及交流输电海缆是影响中频振荡的主要因素;且在上述因素的交互作用下,海上风电柔直送出系统的中频振荡模态呈现“非单调性”特点。最后,基于PSCAD (power systems computer aided design)/EMTDC(electromagne tictransients including DC)建立了如东海上风电柔直送出系统电磁暂态仿真模型,验证了中频振荡特性分析的正确性。展开更多
In this paper, the totally non-positive matrix is introduced. The totally non-positive completion asks which partial totally non-positive matrices have a completion to a totally non-positive matrix. This problem has. ...In this paper, the totally non-positive matrix is introduced. The totally non-positive completion asks which partial totally non-positive matrices have a completion to a totally non-positive matrix. This problem has. in general, a negative answer. Therefore, our question is for what kind of labeled graphs G each partial totally non-positive matrix whose associated graph is G has a totally non-positive completion? If G is not a monotonically labeled graph or monotonically labeled cycle, we give necessary and sufficient conditions that guarantee the existence of the desired completion.展开更多
Particular non-monotonic dose-response curves of many endocrine disrupting chemicals (EDCs) suggest the existence of diverse toxicity mechanisms at different dose levels. As a result, the biological activities of EDCs...Particular non-monotonic dose-response curves of many endocrine disrupting chemicals (EDCs) suggest the existence of diverse toxicity mechanisms at different dose levels. As a result, the biological activities of EDCs cannot be simply exhibited by unique EC50/LD50 values, and the quantitative structure-activity relationship (QSAR) analysis for non-monotonic dose-response relationship becomes an unknown field in the environmental science. In this paper, nine phenols with inverted U-shaped dose-response curves in lymphocyte proliferation test of Carassius auratus were selected. The binding interactions between the phenols and several typical EDCs-related receptors were then explored in a molecular simulation study. The estrogen receptor (ER), androgen receptor (AR), thyroid hormone receptor (TR), bacterial O2 sensing FixL protein (FixL), aryl hydrocarbon receptor (AhR), and the peroxisome proliferator-activated receptor (PPAR) were the target receptors in the study. Linear regression QSAR models for the low and high exposure levels of the compounds were developed separately. The results indicated that the lymphocyte proliferation in the low-dose range might involve ER–mediated process, while the proliferation inhibition in the high dose range was dominated by the acute toxicity of phenols due to receptor occupancy and cell damage.展开更多
文摘In this paper, a new class of three term memory gradient method with non-monotone line search technique for unconstrained optimization is presented. Global convergence properties of the new methods are discussed. Combining the quasi-Newton method with the new method, the former is modified to have global convergence property. Numerical results show that the new algorithm is efficient.
文摘In this paper, we propose and analyze a non-monotone trust region method with non-monotone line search strategy for unconstrained optimization problems. Unlike the traditional non-monotone trust region method, our algorithm utilizes non-monotone Wolfe line search to get the next point if a trial step is not adopted. Thus, it can reduce the number of solving sub-problems. Theoretical analysis shows that the new proposed method has a global convergence under some mild conditions.
文摘A one-dimensional monotone interpolation method based on interface reconstruction with partial volumes in the slope-space utilizing the Hermite cubic-spline, is proposed. The new method is only quartic, however is C2 and unconditionally monotone. A set of control points is employed to constrain the curvature of the interpolation function and to eliminate possible nonphysical oscillations in the slope space. An extension of this method in two-dimensions is also discussed.
基金Supported by National Natural Science Foundation of China
文摘The existence, uniqueness and non-symmetric iterative approximation of solutions for a class of systems of mixed monotone operator equations are discussed. As an application, we utilize, the results presented in this paper to study the existence and uniqueness problems of common solutions for a class of systems of functional equations arising in dynamic programming of multistage decision processes and a class of systems of nonlinear integral equation. The results obtained in this paper not only answer an open question suggested in [3] but also generalize the corresponding results of [1],[2].
基金supported by the National Natural Science Foundation of China (No.10972084)
文摘A new computation scheme proposed to tackle commensurate problems is devel- oped by modifying the semi-analytic approach for minimizing computational complexity. Using the proposed scheme, the limit state equations, usually referred to as the failure surface, are obtained from transformation of an interval variable to a normalized one. In order to minimize the computational cost, two algorithms for optimizing the calculation steps have been proposed. The monotonicity of the objective function can be determined from narrowing the scope of interval variables in normalized infinite space by incorporating the algorithms into the computational scheme. Two examples are used to illustrate the operation and computational efficiency of the approach. The results of these examples show that the proposed algorithms can greatly reduce the computation complexity without sacrificing the computational accuracy. The advantage of the proposed scheme can be even more efficient for analyzing sophistic structures.
文摘Minimal cut sets （or prime implicants： minimal combinations of basic event conditions leading to system failure） are important information for reliability/safety analysis and design. To obtain minimal cut sets for general non-coherent fault trees, including negative basic events or multi-valued basic events, a special procedure such as the consensus rule must be applied to the results obtained by logical operations for coherent fault trees, which will require more steps and time. This paper proposes a simple method for a non-coherent fault tree, whose top event is represented as an AND combination of monotonic sub-trees. A ＂monotonic＂ sub-tree means that it does not have both positive and negative representations for each basic event. It is proven that minimal cut sets can be obtained by a conventional method for coherent fault trees. An illustrative example of a simple event tree analysis shows the detail and characteristics of the proposed method.
文摘Many approaches have been put forward to resolve the variational inequality problem. The subgradient extragradient method is one of the most effective. This paper proposes a modified subgradient extragradient method about classical variational inequality in a real Hilbert interspace. By analyzing the operator’s partial message, the proposed method designs a non-monotonic step length strategy which requires no line search and is independent of the value of Lipschitz constant, and is extended to solve the problem of pseudomonotone variational inequality. Meanwhile, the method requires merely one map value and a projective transformation to the practicable set at every iteration. In addition, without knowing the Lipschitz constant for interrelated mapping, weak convergence is given and R-linear convergence rate is established concerning algorithm. Several numerical results further illustrate that the method is superior to other algorithms.
文摘我国首个海上风电柔性直流送出工程(如东工程)投运初期,在风电场与柔直海上换流站之间出现了320Hz的中频振荡现象,造成柔直系统高频谐波保护动作跳闸。为揭示海上风电柔直送出系统的中频振荡机理及特性,首先,建立了考虑风电机组控制、柔直海上换流器控制、延时环节和交流输电海缆等的海上风电柔直送出系统小信号状态空间模型。然后,从柔直海上换流器内部参数交互、风电场内部参数交互、风电场与柔直海上换流器间参数交互三方面,利用特征值分析法分析了中频振荡的特性及主要影响因素。研究表明,在控制延时的作用下,柔直海上换流器的电流内环、风电机组网侧换流器的电流内环及交流输电海缆是影响中频振荡的主要因素;且在上述因素的交互作用下,海上风电柔直送出系统的中频振荡模态呈现“非单调性”特点。最后,基于PSCAD (power systems computer aided design)/EMTDC(electromagne tictransients including DC)建立了如东海上风电柔直送出系统电磁暂态仿真模型,验证了中频振荡特性分析的正确性。
基金The work was supported by the National Science Foundation of China (10571146).
文摘In this paper, the totally non-positive matrix is introduced. The totally non-positive completion asks which partial totally non-positive matrices have a completion to a totally non-positive matrix. This problem has. in general, a negative answer. Therefore, our question is for what kind of labeled graphs G each partial totally non-positive matrix whose associated graph is G has a totally non-positive completion? If G is not a monotonically labeled graph or monotonically labeled cycle, we give necessary and sufficient conditions that guarantee the existence of the desired completion.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20777035 and 20377022) National High Technology Research and Development Program of China (Grant Nos. 2007AA06Z416 and 2006AA06Z424)
文摘Particular non-monotonic dose-response curves of many endocrine disrupting chemicals (EDCs) suggest the existence of diverse toxicity mechanisms at different dose levels. As a result, the biological activities of EDCs cannot be simply exhibited by unique EC50/LD50 values, and the quantitative structure-activity relationship (QSAR) analysis for non-monotonic dose-response relationship becomes an unknown field in the environmental science. In this paper, nine phenols with inverted U-shaped dose-response curves in lymphocyte proliferation test of Carassius auratus were selected. The binding interactions between the phenols and several typical EDCs-related receptors were then explored in a molecular simulation study. The estrogen receptor (ER), androgen receptor (AR), thyroid hormone receptor (TR), bacterial O2 sensing FixL protein (FixL), aryl hydrocarbon receptor (AhR), and the peroxisome proliferator-activated receptor (PPAR) were the target receptors in the study. Linear regression QSAR models for the low and high exposure levels of the compounds were developed separately. The results indicated that the lymphocyte proliferation in the low-dose range might involve ER–mediated process, while the proliferation inhibition in the high dose range was dominated by the acute toxicity of phenols due to receptor occupancy and cell damage.
