In this work, we consider distributed protocols that operate on arbitrary networks. The analysis of such protocols is challenging, as an arbitrarily chosen network may have limited global symmetry. We describe a methodology that uncovers significant local symmetries by appropriately abstracting node neighborhoods in a network. The local symmetries give rise to uniform compositional proofs of co...

We investigate a network of integrate-and-fire neurons characterized by a distribution of spiking frequencies. Upon increasing the coupling strength, the model exhibits a transition from an asynchronous regime to a nontrivial collective behavior. Numerical simulations of large systems indicate that, at variance with the Kuramoto model, (i) the macroscopic dynamics stays irregular and (ii) the m...

Networks of excitatory and inhibitory neurons display asynchronous irregular (AI) states, where the activities of the two populations are balanced. At the single cell level, it was shown that neurons subject to balanced and noisy synaptic inputs can display enhanced responsiveness. We show here that this enhanced responsiveness is also present at the network level, but only when single neurons ...

A general approach for investigating transport phenomena in porous media is presented. This approach has the capacity to represent various kinds of irregularity in porous media without the need for excessive detail or computational effort. The overall method combines a generalized effective medium approximation (EMA) with a macroscopic continuum model in order to derive a transport equation wit...

tetrahedral cell, parallel rendering, parallel compositing, PixelFlow Volumetric irregular grids are the next frontier to conquer in interactive 3D graphics. Visualization algorithms for rectilinear 2563 data volumes have been optimized to achieve one frame/second to 15 frames/second depending on the workstation. With equivalent computational resources, irregular grids with millions of cells ma...

A deadlock-free multicast scheme called prefix multicasting in irregular networks is studied. In prefix routing, a compact routing table is associated with each node (processor). Basically, each outgoing channel of a node is assigned a special label and an outgoing channel is selected if its label is a prefix of the label of the destination node. Node and channel labeling in an irregular networ...

Understanding self-organized collective dynamics—especially in sparsely connected, noisy, and imperfect networks—has important implications for designing and optimizing task-performing technological systems as well as for deciphering biological structures and functions. We note that stomatal arrays on plant leaves might provide an ideal example of task-performance in this context. Guided by obs...

Exploitation of the wiring flexibility in Networks of Workstations demands configuration methods that can handle dynamic changes in irregular topologies. During reconfiguration of a network based on virtual cut-through or wormhole switching, however, deadlocks in the transition phase between the old and the new routing function must be avoided. The avoidance of such deadlocks will in general ma...

In this paper I propose a real-time method for the detection of hexagonal tiles arranged in an irregular lattice. The method exploits the geometric properties of hexagons to aid detection. The recognition algorithm works by detecting objects on the boundary and peeling them away possibly exposing further internal objects. The algorithm terminates when no further objects can be detected.