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Wyświetlanie 1-4 z 4
Tytuł:
On the global asymptotic stability problem and the Jacobian conjecture
Autorzy:
Drużkowski, L. M.
Powiązania:
https://bibliotekanauki.pl/articles/1839158.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
hipoteza jakobianu
global stability problem
Jacobian Conjecture
Opis:
In this survey, we recall the formulation of the problems and give a review of some nontrivial results in the area. Let F = (F1,...,Fn] : R^n - --> R^n be a C^1 map and let F'(x) and Jac F(x) = det F'(x) denote the Jacobian matrix and the jacobian of F at a point x belongs to R^n, respectively. The Global Asymptotic Stability Problem (GASP) reads as follows: Assume that F(0] = 0 and at any point x belongs to R^n all eigenvalues of F'(x) have negative real parts. Then consider the associated system of differential equations x'j(t] = Fj(x1(t), ...,Xn(t)), j = 1,...,n. The question is whether the solution x[t] = 0 is globally asymptotically stable. If n > 2, then the answer is negative (even if F is a a polynomial automorphism), so from now on (GASP) denotes (GASP) restricted to R^2. In 1963, Olech showed that under the (GASP) assumption (i. e., Jac F[x) > 0 and Trace F'(x) = [...] < 0 for any x belong to R^2) the conclusion of (GASP) is equivalent to the injectivity of F. In 1994, Fessler, and independently Gutierrez, proved the injectivity of F and, due to the above mentioned Olech's equivalence, gave the affirmative answer to the two-dimensional (GASP). Let K denote R or C, n > 1. The Jacobian Conjecture can be formulated as follows: If F = (F1, ... ,Fn) : K^n --> K^n is a polynomial map with a constant nonzero jacobian, then F is a polynomial automorphism (i.e. there exists F^-1 and F^-1 is also a polynomial map). Although the Jacobian Conjecture is still unsolved even in the case of n = 2, it is convenient, to consider the so called Generalized Jacobian Conjecture (for short (GJC)): the Jacobian Conjecture holds for every n > 1. We give a review of some interesting conditions equivalent to the Jacobian Conjecture, including Meisters and Olech's result on the existence of a poly-flow solution of the associated Ważewski equation x'(t) = [F'(x(t))]^-1 (a). We also present, a reduction of (GJC) to the case of F of degree 3 and of special forms, then some partial results, and (JC)'s relations with other problems.
Źródło:
Control and Cybernetics; 2005, 34, 3; 747-762
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tabu search: global intensification using dynamic programming
Autorzy:
Wilbaut, C.
Hanafi, S.
Fréville, A.
Balev, S.
Powiązania:
https://bibliotekanauki.pl/articles/970871.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
programowanie dynamiczne
tabu search
dynamic programming
global intensification
multidimensional 0-1 knapsack problem
Opis:
Tabu search has proven highly successful in solving hard combinatorial optimization problems. In this paper, we propose a hybrid method that combines adaptive memory, sparse dynamic programming, and reduction techniques to reduce and explore the search space. Our approach starts with a bi-partition of the variables, involving a small core problem, which never exceeds 15 variables, solved using the "forward" phase of the dynamic programming procedure. Then, the remaining subspace is explored using tabu search, and each partial solution is completed with the information stored during the forward phase of dynamic programming. Our approach can be seen as a global intensification mechanism, since at each iteration, the move evaluations involve solving a reduced problem implicitly. The proposed specialized tabu search approach was tested in the context of the multidimensional 0-1 knapsack problem. Our approach was compared to ILOG's commercial product CPLEX and to the corresponding "pure" tabu search (i.e., without a core problem) for various sets of test problems available in OR-libraries. The results are encouraging. In particular, this enhances the robustness of the approach, given that it performs better than the corresponding pure tabu search most of the time. Moreover, our approach compares well with CPLEX when the number of variables is large; it is able to provide elite feasible solutions in a very reasonable amount of computational time.
Źródło:
Control and Cybernetics; 2006, 35, 3; 579-598
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The corridor method: a dynamic programming inspired metaheuristic
Autorzy:
Sniedovich, M.
Viß, S.
Powiązania:
https://bibliotekanauki.pl/articles/970877.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
programowanie dynamiczne
metaheuristics
dynamic programming
curse of dimensionality
very large neighborhoods
corridor method
global optimization
move-based
method-based
traveling salesman problem
Opis:
This paper presents a dynamic programming inspired metaheuristic called Corridor Method. It can be classified as a method-based iterated local search in that it deploys method-based neighborhoods. By this we mean that the search for a new candidate solution is carried out by a fully-fledged optimization method and generates a global optimal solution over the neighborhood. The neighborhoods are thus constructed to be suitable domains for the fully-fledged optimization method used. Typically, these neighborhoods are obtained by the imposition of exogenous constraints on the decision space of the target problem and therefore must be compatible with the optimization method used to search these neighborhoods. This is in sharp contrast to traditional metaheuristics where neighborhoods are move-based, that is, they are generated by subjecting the candidate solution to small changes called moves. While conceptually this method-based paradigm applies to any optimization method, in practice it is best suited to support optimization methods such as dynamic programming, where it is easy to control the size of a problem, hence the complexity of algorithms, by means of exogenous constraints. The essential features of the Corridor Method are illustrated by a number of examples, including the traveling salesman problem, where exponentially large neighborhoods are searched by a linear time/space dynamic programming algorithm.
Źródło:
Control and Cybernetics; 2006, 35, 3; 551-578
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A stable homotopy approach to horizontal linear complementarity problems
Autorzy:
Ralph, D.
Powiązania:
https://bibliotekanauki.pl/articles/206132.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
ciągłość pseudo-Lipschitza
metoda homotopii
rozwiązanie stałe
system kawałkami afiniczny
active set method
global metric regularity
homotopy method
horizontal linear complementarity problem
mathematical program with complementarity constraints
MPCC
MPCC-LICQ
MPEC
path following
piecewise affine system
pseudo-Lipschitz continuity
QPCC
stable solution
Opis:
We are interested in the solution of Horizontal Linear Complementarity Problems, HLCPs, that is complementarity problems with more variables than equations. Globally metrically regular HLCPs have nonempty solution sets that are stable with respect to "right-hand-side perturbations" of the data, hence are numerically attractive. The main purpose of the paper is to show how the stability on conditioning properties of globally metrically regular HLCPs are preserved by a homotopy framework for solving the HLCP that finds a "stable" direcaion at each iteration as a local minimizer of a strongly convex quadratic program with linear complementarity constraints, QPCC. Apart from intrinsic interest in numerical solution of HLCPs, this investigation has application in solving horizontal nonlinear complementarity problems and more broadly in the area of mathematical programs with complementarity constraints, MPCCs.
Źródło:
Control and Cybernetics; 2002, 31, 3; 575-599
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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