We consider cell centered nite di erence discretizations with lo cal re nement for nonsymmetric boundary value problems Preconditioners with mesh independent convergence properties for corresponding matrices are constructed The method is illustrated with numerical experiments

This paper studies the in uence of knowledge difference on the performance of a search agent | { a controllable camera that can pan, tilt and zoom. The task of the agent is to search for a 3D target within a 3D environment. The goal is to maximize the probability of detecting the target within a given period of time. The search agent does this by autonomously controlling its state parameters to...

In this paper, we present Clock Diierence Diagrams, a new BDD-like data-structure for eeective representation and manipulation of certain non-convex subsets of the Euclidean space, notably those encountered in veriication of timed automata. It is shown that all set-theoretic operations including inclusion checking may be carried out eeciently on Clock Diierence Diagrams. Other central operation...

In the eld of pattern matching, there is a clear trade-o between e ectiveness, accuracy and robustness on one hand and e ciency and simplicity on the other hand. For example, matching patterns more e ectively by using a more general class of transformations usually results in a considerable increase of computational complexity. In this paper, we introduce a general pattern matching approach whi...

In this paper we present a bottom-up algorithm called MRI to induce logic programs from their examples. This method can induce programs with a base clause and more than one recursive clause from a very small number of examples. MRI is based on the analysis of saturations of examples. It rst generates a path structure, which is an expression of a stream of values processed by predicates. The con...

On q-Di®erence Equations Moemen H. Abu-Risha Department of Mathematics Cairo University, Eygpt E-mail: [email protected] We give an investigation of some properties of solutions of linear q¡di®erence equations de ̄ned on an interval [a;1): The cases a = 0 and a > 0 are essentially di®erent. The study of the latter case is necessary for the derivation of asymptotic formulae and oscil...

Time series in many areas of application often display local or global trends. Typical models that provide statistical \explanations" of such trends are, for example, polynomial regression, smooth bounded trends that are estimated nonparametrically, and di erence-stationary processes such as, for instance, integrated ARIMA processes. In addition, there is a fast growing literature on stationary...

In this paper an exact model for a basic rst order -modulator is derived by means of a di erence equation. Furthermore, the second order di erence equation describing a second order -modulator is given. In addition, the conditions under which by using the exact rst order model this second order di erence equation is getting a simpler form is given too.

The iterated di erence of polyhedra V P n P n Pk has been proposed independently in and as a su cient condition for V to be exactly computable by a two layered neural network An algorithm checking whether V IR is an iterated di erence of polyhedra is proposed in However this algorithm is not practically usable because it has a high computational complexity and it was only conjectured to stop wi...

"In this article, we give su cient conditions for the existence, uniqueness and Ulam{Hyers stability of solutions a coupled system two-point nabla fractional di erence boundary value problems subject to anti-periodic conditions, using vector approach Precup [4, 14, 19, 21]. Some examples are included illustrate theory."