Many different kinds of names (identifiers) are used in computer systems. Names are resolved (interpreted) in a context. A context is a function that maps names to entities. Multiple contexts allow the flexibility of giving different meanings to a name in different parts of the system; however, there are situations where it is desirable for the meaning of a name to be the same in different parts. This property is called coherence in naming. Since the meaning of a name depends on the context selected, the analysis of coherence is based on the notion of closure mechanisms-implicit rules that select a context for resolving names. The authors define coherence and show how it is affected by various closure mechanisms. Then they present several approaches for dealing with the lack of coherence. Incoherence arises from selecting an incorrect context, and consequently, closure mechanisms are involved in the solutions.>

The limit sets of cellular automata, defined by Wolfram, play an important role in applications of cellular automata to complex systems. A number of results on limit sets are proved, considering both finite and infinite configurations of cellular automata. The main concern of this paper is with testing membership and (essential) emptiness of limit sets for linear and two-dimensional cellular automata.

A self-stabilizing system has the property that, no matter how it is perturbed, it eventually returns to a legitimate configuration. Dijkstra originally introduced the self-stabilization problem and gave several solutions for a ring of processors in his 1974 Communications of the ACM paper. His solutions use a distinguished processor in the ring, which effectively acts as a controlling element to drive the system toward stability. Dijkstra has observed that a distinguished processor is essential if the number of processors in the ring is composite. We show, by presenting a protocol and proving its correctness, that there is a self-stabilizing system with no distinguished processor if the size of the ring is prime. The basic protocol uses Θ ( n 2 ) states in each processor when n is the size of the ring. We modify the basic protocol to obtain one that uses Θ ( n 2 /ln n ) states.

A previously proposed livelock-free modification of the empty-slot protocol for slotted rings is reviewed, and a new livelock-free modification is described.

Tills paper establishes several lower bounds of the form f~(nlogn) for the number of messages needed to find the maximum label in a circular configuration of n labeled processes with no central controller.

This paper is about two constructions for transforming planar systolic arrays. By a systolic array we mean a uniformly structured processor configuration that allows only local communication (between neighbour processors) and supports high throughout by pipelining. Such configurations are suitable for VLSI implementation [4, 5].

This paper deals with the problem of finding the maximum of a distributed set of distinct integers. The problem is to be solved by a completely distributed asynchronous algorithm.