Bilkent University

Department of Computer Engineering

Ph.D DISSERTATION

Graph Problems in Call Models and Switching Networks

Abdullah Atmaca

Ph.D Candidate

(Supervisor: Prof. Dr. Cevdet Aykanat, Co-Supervisor: Prof. Dr. A. Yavuz Oruç)

Computer Engineering Department

Bilkent University

In the first part of this dissertation, we focus on graph problems that arise in call models. Such models are used to study the combinatorial properties of certain types of calls that include unicast, multicast, and bicast interconnections. Here we focus on bicast calls, and provide closed-form formulas for the number of unlabeled bicast calls when either the number of callers or number of receivers is fixed to 2 or 3. We then obtain lower and upper bounds on the number of such calls by solving an open problem in graph theory, namely counting the number of unlabeled bipartite graphs. Next, these results are extended to left (right) set labeled and set labeled bipartite graphs. In the second part of the dissertation, we focus on wiring and routing problems for one-sided, binary tree switching networks. Specifically, we reduce the O(n) time complexity of the routing algorithm for the one-sided, binary tree switching network to O(lg n). We also present a new wiring algorithm for one-sided, binary tree switching networks. Finally, an algorithm is presented to locate the cluster in which the terminals of the corresponding one-sided binary tree switching network are paired. The time complexity of this algorithm is shown to be O(lg n).

Keywords: Bipartite graphs, Polya’s counting theorem, cycle index polynomial, switching networks, call models.

DATE: 02 August 2018, Thursday @ 10:00

PLACE: EA-409