Volume 16, 1997, No. 6


Broadcasting in the Arrowhead Torus

D. Désérable

Abstract. The "arrowhead torus" is a hierarchical Cayley graph that we define on the triangular (or "hexavalent") grid. A 3-port wormhole broadcasting protocol is derived first from construction, then improved by using edge-disjoint forests. A store-and-forward broadcasting protocol is derived afterwards, then improved by mixing pipelining and arc-disjoint spanning trees. Costs are given in constant and linear time and compared with lower bounds.

 

Developing Intelligent Tutoring Systems for Mathematics

M. das Gracas Volpe Nunes, R. Hasegawa

Abstract. This work presents Protema, an environment for accessing and/or constructing intelligent tutoring systems for mathematics.  It uses a general representation model for mathematical knowledge and it proposes a system architecture for intelligent tutoring systems in any mathematical subdomain (Arqtema) as well as an authoring environment (Tootema) for constructing Arqtema-based tutoring systems in a chosen subdomain. The general representation model maps any mathematical theory into a complex relationship among concepts, results and examples. Arqtema extends this model by including a bug catalog with the most common students misconceptions as well as a set of related exercises, which all together constitute the domain module.

 

Vertex-Disjoint Paths in Cayley Color Graphs

P. Kulasinghe, S. Bettayeb

Abstract. In this paper, we study the strong connectivity of Cayley color graphs when a certain number of vertices are removed. We prove that there are ½D½ vertex-disjoint paths from every vertex to every other vertex in a Cayley color graph associated with a finite group G and a non redundant generating set D for G. We also extend this result to a certain class of Cayley graphs.

 

MONADS-DPV: An Object-Oriented Graphical Support for Developing Concurrent Software System

P. Kacsuk, G. Haring, G. Dózsa, Sz. Ferenczi, T. Fadgyas,  G. Pigel

Abstract. Programming parallel computers, consisting of multiple powerful processing elements, is a hard task. A suitable very high level notation is needed by which the programmer can express an algorithm for a given problem in a style both a multiprocessor machine can efficiently execute and, at the same time,  can be easily understood by humans. In this paper a graphical notation is presented facilitating layered structures in object-oriented parallel programs in a way both the graphical and the textual parts could be easily integrated. Applying our proposed notation can substantially reduce the efforts of the programmer to make very high level programs for high performance parallel computers.


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