Showing papers on "Network topology published in 1969"

The Design of Minimum-Cost Survivable Networks

Abstract: We consider the problem of designing a network which satisfies a prespecified survivability criterion with minimum cost. The survivability criterion demands that there be at least r_{ij} node disjoint paths between nodes i and j , where (r_{ij}) is a given redundancy requirement matrix. This design problem appears to be at least as difficult as the traveling salesman problem, and present techniques cannot provide a computationally feasible exact solution. A heuristic approach is described, based on recent work on the traveling salesman problem, which leads to a practical design method. Algorithms are described for generating starting networks, for producing local improvements in given networks, and for testing the redundancy of networks at each stage. This leads to networks which are locally optimum with respect to the given transformation. Randomizing the starting solution ensures that the solution space is widely sampled. Two theorems are given which allow great reduction in the amount of computation required to test the redundancy of a network. Finally, some design examples are given.

On the Decomposition of Networks in Minimally Interconnected Subnetworks

Abstract: The problem of decomposing a network into different groups of electrical components, which are interconnected by the minimum number of leads, is discussed. For this purpose, minimal groups of components are defined as the ones fulfilling a chosen minimality criterion, and a number of their properties are illustrated. Some of these properties are directly employed in a procedure for the determination of all the minimal groups for a given network.

General Purpose Programs for the Frequency Domain Analysis of Microwave Circuits

Abstract: This paper describes microwave circuit analysis programs techniques for general purpose which perform frequency domain analyses. Differing techniques used in two programs are described. The first uses transfer matrix analysis and is limited to networks having tree structured topologies and two-port devices such as transmission lines, stubs and lumped elements. It runs on a time-shared computer and is used for interactive design. The second program can analyze any linear network including those with multiport elements such as coupled transmission lines. This uses a nodal representation for the circuit and relies on inverting an admittance matrix to perform the analysis. In the first program the user describes his circuit in terms of topology as well as circuit elements. By this technique, a considerable reduction in computer size needed to run this program is effected. A 60 element circuit can be run on a commercial time-sharing service with less than 6K words of available core. The second program requires a large computer; for example, 32K words or core storage are required to analyze a 50 node circuit.

A New Modification of Topological Formulas

Abstract: A new modification of passive network topological formulas is given, which makes it possible to use a single treefinding program to calculate the network functions. The modified formulas require the calculation of fewer sets of two-trees than a previous method.