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排序方式: 共有25178条查询结果,搜索用时 62 毫秒
1.
Ranking fuzzy numbers with integral value   总被引:110,自引:0,他引:110  
Ranking fuzzy numbers is important in decision making. Since very often the alternatives are evaluated by fuzzy numbers in a vague environment, a comparison between these fuzzy numbers is indeed a comparison between alternatives. This paper proposes a method of ranking fuzzy numbers with integral value. The method, which is independent of the type of membership functions used and the normality of the functions, can rank more than two fuzzy numbers simultaneously. It is relatively simple in computation, especially in ranking triangular and trapezoidal fuzzy numbers. Further, an index of optimism is used to reflect the decision maker's optimistic attitude. Discussion on comparative advantages is included.  相似文献
2.
A nonsmooth version of Newton's method   总被引:68,自引:0,他引:68  
Newton's method for solving a nonlinear equation of several variables is extended to a nonsmooth case by using the generalized Jacobian instead of the derivative. This extension includes the B-derivative version of Newton's method as a special case. Convergence theorems are proved under the condition of semismoothness. It is shown that the gradient function of the augmented Lagrangian forC 2-nonlinear programming is semismooth. Thus, the extended Newton's method can be used in the augmented Lagrangian method for solving nonlinear programs.This author's work is supported in part by the Australian Research Council.This author's work is supported in part by the National Science Foundation under grant DDM-8721709.  相似文献
3.
研究一类具有时滞和基于比率的三种群食物链捕食-被捕食动力学模型.证明了该系统在适当条件下的一致持久性;通过构造Lyapunov泛函,得到了该系统正平衡点全局渐近稳定的充分条件.  相似文献
4.
四阶奇异边值问题的正解   总被引:56,自引:0,他引:56       下载免费PDF全文
韦忠礼 《数学学报》1999,42(4):715-722
本文利用上下解方法和极大值原理给出了四阶微分方程的奇异边值问题有C2[0,1]和C3[0,1]正解存在的充分必要条件.  相似文献
5.
6.
On the limited memory BFGS method for large scale optimization   总被引:48,自引:0,他引:48  
We study the numerical performance of a limited memory quasi-Newton method for large scale optimization, which we call the L-BFGS method. We compare its performance with that of the method developed by Buckley and LeNir (1985), which combines cycles of BFGS steps and conjugate direction steps. Our numerical tests indicate that the L-BFGS method is faster than the method of Buckley and LeNir, and is better able to use additional storage to accelerate convergence. We show that the L-BFGS method can be greatly accelerated by means of a simple scaling. We then compare the L-BFGS method with the partitioned quasi-Newton method of Griewank and Toint (1982a). The results show that, for some problems, the partitioned quasi-Newton method is clearly superior to the L-BFGS method. However we find that for other problems the L-BFGS method is very competitive due to its low iteration cost. We also study the convergence properties of the L-BFGS method, and prove global convergence on uniformly convex problems.This work was supported by the Applied Mathematical Sciences subprogram of the Office of Energy Research, U.S. Department of Energy, under contract DE-FG02-87ER25047, and by National Science Foundation Grant No. DCR-86-02071.  相似文献
7.
Over the past decade, the field of finite-dimensional variational inequality and complementarity problems has seen a rapid development in its theory of existence, uniqueness and sensitivity of solution(s), in the theory of algorithms, and in the application of these techniques to transportation planning, regional science, socio-economic analysis, energy modeling, and game theory. This paper provides a state-of-the-art review of these developments as well as a summary of some open research topics in this growing field.The research of this author was supported by the National Science Foundation Presidential Young Investigator Award ECE-8552773 and by the AT&T Program in Telecommunications Technology at the University of Pennsylvania.The research of this author was supported by the National Science Foundation under grant ECS-8644098.  相似文献
8.
Continuous-Time Mean-Variance Portfolio Selection: A Stochastic LQ Framework   总被引:43,自引:0,他引:43  
This paper is concerned with a continuous-time mean-variance portfolio selection model that is formulated as a bicriteria optimization problem. The objective is to maximize the expected terminal return and minimize the variance of the terminal wealth. By putting weights on the two criteria one obtains a single objective stochastic control problem which is however not in the standard form due to the variance term involved. It is shown that this nonstandard problem can be ``embedded' into a class of auxiliary stochastic linear-quadratic (LQ) problems. The stochastic LQ control model proves to be an appropriate and effective framework to study the mean-variance problem in light of the recent development on general stochastic LQ problems with indefinite control weighting matrices. This gives rise to the efficient frontier in a closed form for the original portfolio selection problem. Accepted 24 November 1999  相似文献
9.
图的距离不大于β的任意两点可区别的边染色   总被引:38,自引:1,他引:37       下载免费PDF全文
本文提出了图的距离不大于β的任意两点可区别的边染色,即D(β)-点可区别的边染色(简记为D(β)-VDPEC).并得到了一些特殊图类,如圈、完全图、完全二部图、扇、轮、树以及一些联图的D(β)-点可区别的边色数,文后提出了相关的猜想.  相似文献
10.
四阶奇异边值问题两个正解的存在性   总被引:32,自引:1,他引:31       下载免费PDF全文
庞常词  韦忠礼 《数学学报》2003,46(2):403-410
本文利用锥压缩和锥拉伸不动点定理,给出了四阶微分方程奇异边值问题两 个C2[0,1]和C3[0,1]正解的存在性.  相似文献
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