Showing papers by "Stavros D. Nikolopoulos published in 1997"

Addressing network survivability issues by finding the K-best paths through a trellis graph

Abstract: Due to the increasing reliance of society on the timely and reliable transfer of large quantities of information (such as voice, data, and video) across high speed communication networks, it is becoming important for a network to offer survivability, or at least graceful degradation, in the event of network failure. In this paper we aim to offer a solution in the selection of the K-best disjoint paths through a network by using graph theoretic techniques. The basic approach is to map an arbitrary network graph into a trellis graph which allows the application of computationally efficient methods to find disjoint paths. Use of the knowledge of the K-best disjoint paths for improving the survivability of ATM networks at the virtual path and virtual circuit level is discussed.

On complete systems of invariants for small graphs

Abstract: We define a small graph to be one with n ≤ 6 nodes. The celebrated Graph Isomorphism Problem (GIP) consists in deciding whether or not two given graphs are isomorphic, i.e., whether there is a bijective mapping from the nodes of one graph onto those of the other such that adjacency is preserved. An interesting algorithmic approach to graph isomorphism problem uses the “code” (sometimes called a complete system of invariants). Following this approach, two graphs are isomorphic if and only if they have the same code. We propose several complete sets of invariants to settle the GIP for small graphs. Note that no complete system of invariants for a graph is known, except for those that are equivalent to the entire adjacency matrix or list of adjacencies.