  In this paper we consider a continuous-time anisotropic swarm model with an
attraction/repulsion function and study its aggregation properties. It is shown
that the swarm members will aggregate and eventually form a cohesive cluster of
finite size around the swarm center. We also study the swarm cohesiveness when
the motion of each agent is a combination of the inter-individual interactions
and the interaction of the agent with external environment. Moreover, we extend
our results to more general attraction/repulsion functions. The model in this
paper is more general than isotropic swarms and our results provide further
insight into the effect of the interaction pattern on individual motion in a
swarm system.
