We propose a new Web documentation database as a supporting environment of the Multimedia Micro-University project. The design of this database facilitates a Web documentation development paradigm that we have proposed earlier. From a script description to its implementation as well as testing records, the database and its interface allow the user to design Web documents as virtual courses to be used in a Web-savvy virtual library. The database supports object reuse and sharing, as well as referential integrity and concurrence. In order to allow real-time course demonstration, we also propose a simple course distribution mechanism, which allows the pre-broadcast of course materials. The system is implemented as a three-tier architecture which runs under MS Windows and other platforms.

A new approach to the design of collective communication operations in wormhole-routed mesh networks is described. The approach extends the concept of dominating sets in graph theory by accounting for the relative distance-insensitivity of the wormhole switching strategy and by taking advantage of a multiport communication architecture, which allows each node to simultaneously transmit messages on different outgoing channels. Collective communication operations are defined in terms of sets of extended dominating nodes (EDNs). The nodes in a set of EDNs can deliver (receive) messages to (from) a different, larger set of nodes in a single message-passing step under dimension-ordered wormhole routing and without channel contention among messages. The EDN model can be applied to different collective operations in 2D and 3D mesh networks. The authors focus on EDN-based broadcast and global combine operations. Performance evaluation results are presented that confirm the advantage of this approach over other methods.

A new approach to broadcast in wormhole-routed two- and three-dimensional torus networks is proposed. The underlying network is assumed to support only deterministic, dimension-ordered unicast routing. The approach extends the graph theoretical concept of dominating nodes by accounting for the relative distance-insensitivity of the wormhole routing switching strategy. The proposed algorithm also takes advantage of an all-port communication architecture, which allows each node to simultaneously transmit messages on different outgoing channels. The resulting broadcast operation is based on a tree structure that uses multiple levels of extended dominating nodes(EDNs). Performance results are presented that confirm the advantage of this method over other approaches.

A new approach to broadcast in wormhole-routed three-dimensional (3D) mesh networks is proposed. The approach extends the concept of dominating sets from graph theory by accounting for the relative distance-insensitivity of the wormhole routing switching strategy and by taking advantage of an all-port communication architecture, which allows each node to simultaneously transmit messages on different outgoing channels. The resulting broadcast operation is based on a tree structure that is composed of multiple levels of extended dominating nodes (EDN). Performance evaluation results, in the form of analysis and simulation, are presented that confirm the advantage of this technique over the recursive doubling approaches to broadcast.

A new model for broadcast in wormhole-routed networks is proposed. The model uses and extends the concept of dominating sets in order to systematically develop efficient broadcast algorithms for all-port wormhole-routed systems, in which each node can simultaneously transmit messages on different outgoing channels. In this paper, two broadcast algorithms for two-dimensional (2D) mesh networks are presented. In the first approach, the source node uses a multicast algorithm to deliver the message to a set of dominating nodes, which can subsequently deliver the message to all other nodes in the network in a single message-passing step. This algorithm requires at most [log2N] steps, where N is the total number of nodes in the network, although in many cases only [log2N]−1 steps are needed. The second algorithm, called the D-node algorithm, reduces the number of steps by using multiple levels of dominating nodes in a recursive manner. For square meshes containing N=22(k+2) nodes, k≥0, the D-node algorithm requires at most k+4 steps. Similar upper bounds are shown to hold for meshes of other sizes and shapes. For specific source nodes and mesh shapes, the number of steps is shown to equal the theoretical lower bound of [log5N]. A simulation study confirms the advantage of the D-node algorithm, under various system parameters and conditions, over other broadcast algorithms.