The near future will present large scale parallel computers, able to provide computing power of more than one TFlop per second. It is commonly agreed that these systems will be based on the model of asynchronous processors connected by a point to point network. There are a number of diierent network architectures presented in the past. In this paper we present an architectural principle that co...

This is a complete exposition of a tight version of a fundamental theorem of computational complexity due to Levin: The inherent space complexity of any partial function is very accurately speciiable in a 1 way, and every such speciication that is even 2 does characterize the complexity of some partial function, even one that assumes only the values 0 and 1.

We suggest the binding of neutral atoms to a current carrying wire through the interaction between the atomic magnetic dipole moment and the wire's magnetic field. The theoretical description is based upon an extension of the concept of supersymmetry to multicomponent wave functions. A solution for spin 2 particles is obtained directly in coordinate space. Spin 1 particles are considered as wel...

Pristine silicon whiskers are compared through energy analysis by separating the surface, edge, and bulk contributions, and by energy computation for a variety of structures and diameters d. It is shown that for d<6 nm a polycrystalline wire of five-fold symmetry, rather than single-crystal types, represents the ground state. It remains stable in molecular dynamics tests up to approximately 100...

The present paper is primarily concerned with modeling complex turbulent wall-bounded flow in spray-painting processes by using a commercial CFD code. Computational results of turbulent channel flow with low Reynolds numbers are compared with DNS data in order to obtain the performance of turbulence models and near wall treatments. The realizable k-ε model with the nonequilibrium wall function ...

For any matroid M realizable over Q, we give a combinatorial interpretation of the Tutte polynomial T M (x; y) which generalizes many of its known interpretations and specializations, including Tutte's coloring and ow interpretations of T M (1 ? t; 0); T M (0; 1 ? t), Crapo and Rota's nite eld interpretation of T M (1 ? q k ; 0), the interpretation in terms of the Whitney corank-nullity polynom...

Idempotent nonlinear filters may be viewed as extensions of the class of (non-realizable) ideal linear filters, and one of their characteristic features is that they reduce any input sequence {x k } to a root after one pass. This paper explores some new constructions of idempotent nonlinear filters, using ideas from algebraic category theory, which provides a natural basis for considering casca...

This paper studies the realizability property of bilinear input-output (i/o) models in the classical state space form. Constraints on the parameters of the bilinear i/o model are suggested that lead to realizable models. The complete list of 2nd and 3rd order realizable inputoutput bilinear models together with the corresponding state equations is given. In the general case some subclasses of r...

In this paper, we propose a method for realizing a polyhedral graph as a deltahedron, i.e., a polyhedron with congruent equilateral triangles as faces. Our experimental result shows that there are graphs that are not realizable as deltahedra. We provide an example of non-realizable graphs which are obtained by trying to construct deltahedra from each of the simple cubic polyhedral graphs with u...