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排序方式: 共有586条查询结果,搜索用时 125 毫秒
1.
Stability analysis of some representative numerical methods for systems of neutral delay-differential equations (NDDEs) is considered. After the establishment of a sufficient condition of asymptotic stability for linear NDDEs, the stability regions of linear multistep, explicit Runge-Kutta and implicitA-stable Runge-Kutta methods are discussed when they are applied to asymptotically stable linear NDDEs. Some mentioning about the extension of the results for the multiple delay case is given.  相似文献
2.
Summary. This paper deals with the stability analysis of implicit Runge-Kutta methods for the numerical solutions of the systems of neutral delay differential equations. We focus on the behavior of such methods with respect to the linear test equations where ,L, M and N are complex matrices. We show that an implicit Runge-Kutta method is NGP-stable if and only if it is A-stable. Received February 10, 1997 / Revised version received January 5, 1998  相似文献
3.
4.
Multiple Zeta Values at Non-Positive Integers   总被引:2,自引:0,他引:2  
Values of Euler-Zagier's multiple zeta function at non-positive integers are studied, especially at (0,0,...,–n) and (–n,0,...,0). Further we prove a symmetric formula among values at non-positive integers.  相似文献
5.
Self-similar processes with independent increments   总被引:2,自引:0,他引:2  
Summary A stochastic process {X t t 0} onR d is called wide-sense self-similar if, for eachc>0, there are a positive numbera and a functionb(t) such that {X ct } and {aX t +b(t)} have common finite-dimensional distributions. If {X t } is widesense self-similar with independent increments, stochastically continuous, andX 0=const, then, for everyt, the distribution ofX t is of classL. Conversely, if is a distribution of classL, then, for everyH>0, there is a unique process {X (H) t } selfsimilar with exponentH with independent increments such thatX 1 has distribution . Consequences of this characterization are discussed. The properties (finitedimensional distributions, behaviors for small time, etc.) of the process {X (H) t } (called the process of classL with exponentH induced by ) are compared with those of the Lévy process {Y t } such thatY 1 has distribution . Results are generalized to operator-self-similar processes and distributions of classOL. A process {X t } onR d is called wide-sense operator-self-similar if, for eachc>0, there are a linear operatorA c and a functionb c (t) such that {X ct } and {A c X t +b c (t)} have common finite-dimensional distributions. It is proved that, if {X t } is wide-sense operator-self-similar and stochastically continuous, then theA c can be chosen asA c =c Q with a linear operatorQ with some special spectral properties. This is an extension of a theorem of Hudson and Mason [4].  相似文献
6.
Closed orbits in homology classes   总被引:2,自引:0,他引:2  
Dedicated to Pr. Akihiko Morimoto for his 60th birthday  相似文献
7.
We generalize the standard vehicle routing problem with time windows by allowing both traveling times and traveling costs to be time-dependent functions. In our algorithm, we use a local search to determine routes of the vehicles. When we evaluate a neighborhood solution, we must compute an optimal time schedule for each route. We show that this subproblem can be efficiently solved by dynamic programming, which is incorporated in the local search algorithm. The neighborhood of our local search consists of slight modifications of the standard neighborhoods called 2- opt*, cross exchange and Or-opt. We propose an algorithm that evaluates solutions in these neighborhoods more efficiently than the ones computing the dynamic programming from scratch by utilizing the information from the past dynamic programming recursion used to evaluate the current solution. We further propose a filtering method that restricts the search space in the neighborhoods to avoid many solutions having no prospect of improvement. We then develop an iterated local search algorithm that incorporates all the above ingredients. Finally we report computational results of our iterated local search algorithm compared against existing methods, and confirm the effectiveness of the restriction of the neighborhoods and the benefits of the proposed generalization.  相似文献
8.
Homotopy equivalences in a principal fibre space   总被引:1,自引:0,他引:1  
9.
Concave Programming in Control Theory   总被引:1,自引:0,他引:1  
We show in the present paper that many open and challenging problems in control theory belong the the class of concave minimization programs. More precisely, these problems can be recast as the minimization of a concave objective function over convex LMI (Linear Matrix Inequality) constraints. As concave programming is the best studied class of problems in global optimization, several concave programs such as simplicial and conical partitioning algorithms can be used for the resolution. Moreover, these global techniques can be combined with a local Frank and Wolfe feasible direction algorithm and improved by the use of specialized stopping criteria, hence reducing the overall computational overhead. In this respect, the proposed hybrid optimization scheme can be considered as a new line of attack for solving hard control problems.Computational experiments indicate the viability of our algorithms, and that in the worst case they require the solution of a few LMI programs. Power and efficiency of the algorithms are demonstrated for a realistic inverted-pendulum control problem.Overall, this dedication reflects the key role that concavity and LMIs play in difficult control problems.  相似文献
10.
Picard principle for negative planar potentials   总被引:1,自引:0,他引:1  
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