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An alternator is a network of concurrent nodes, which satisfies the following conditions: (i) if one node enters its critical section, no neighboring nodes could enter their critical sections at the same computing phase; (ii) along any infinite computing phases, each node enters its critical section infinitely often. An alternator is said to exhibit strong fairness if condition (ii) is changed to: between any two consecutive critical steps of a node, all neighbors enter their critical sections exactly once. In this paper, we propose a state-optimal alternator algorithm for uniform rings with n nodes, where n is any positive integer greater than one. The proposed algorithm operates correctly for synchronous mode. Every node maintains only a two-state variable. The proposed algorithm has the snap property that the system always satisfies condition (i) of the alternator even if some transient fault occurs. The stabilization time of the proposed alternator algorithm is O(n) phases. After stabilization, the system satisfies the strong fairness property and achieves the maximal performance. We say that an alternator achieves the maximal performance if a node is allowed to enter its critical section when both its neighbors do not enter their critical sections. In the worst case, the proposed algorithm allows each node to enter its critical section every three phases. [ABSTRACT FROM AUTHOR]

Applications of computers to humanistic research rely increasingly on SGML or XML markup; it is a persistent challenge to find suitable representations in these tree-based formalisms, for the overlap of textual features. SGML lends itself to a straightforward data model with a simple relationship between markup (element and attributes) and features or structures in the text. Barnard et al. (Computers and the Humanities, 22: 265-76, 1988; 29: 21131, 1995) and TEI (Guidelines for Electronic Text Encoding and Interchange, 1994) have presented methods for registering the existence of overlap using SGML notations, but these methods are often felt to be unsatisfactory, in part (we argue) because they complicate the otherwise straightforward SGML data model. The MECS and CONCUR notations described here allow the straightforward markup of overlapping textual features. CONCUR further allows the formulation of useful document grammars for concurrent hierarchies of textual features. The theoretical and practical advantages outweigh the practical disadvantages, and the humanities computing community should begin serious experimentation with CONCUR. [ABSTRACT FROM AUTHOR]