Abstract. Given the demand between each origin-destination pair on a network, the planar hub location problem is to locate the multiple hubs anywhere on the plane and to assign the traffic to them so as to minimize the total travelling cost. The trips between any two points can be nonstop (no hubs used) or started by visiting any of the hubs. The travel cost between hubs is discounted with a fa...

Traffic flows on networks have been the subject of intensive study [1]. We study this problem in the context of a two dimensional lattice of nodes and hubs. When many messages flow on the lattice, hubs which lie on many message paths tend to get congested. We rank the hubs by their coefficient of betweenness centrality (CBC) [2] which is defined as the number of messages Nk running through a gi...

The Cumulative Capacitated Vehicle Routing Problem (CCVRP) is a variation of the classical Capacitated Vehicle Routing Problem in which the objective is the minimization of the sum of arrival times at customers, instead of the total routing cost. This paper presents an adaptive large neighborhood search heuristic for the CCVRP. This algorithm is applied to a set of benchmark instances and compa...

1997 ii ACKNOWLEDGEMENTS We would like mostly to thank Mr. Peter Keenan, who was as much a partner as a supervisor, for his invaluable time and erudite guidance during the summer. We must also pay tribute to our parents for their encouragement and support, not only for the duration of this dissertation, but throughout the year. ABSTRACT The Capacitated Arc Routing Problem is a NP-hard arc routi...

Studies of nervous system connectivity, in a wide variety of species and at different scales of resolution, have identified several highly conserved motifs of network organization. One such motif is a heterogeneous distribution of connectivity across neural elements, such that some elements act as highly connected and functionally important network hubs. These brain network hubs are also densel...