David Mutchler

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There are several replica control algorithms for managing replicated files in the face of network partitioning due to site or communication link failures. Pessimistic algorithms ensure consistency at the price of reduced availability; they permit at most one (distinguished) partition to process updates at any given time. The best known pessimistic(More)
An approach to software reliability and certification is presented that is based on the use of three mathematical models: the sampling, component, and certification models. The approach helps reduce reliability analysis to a problem that can be evaluated and manipulated through a series of spreadsheets. This approach was motivated by interest in applying(More)
There are several consistency control algorithms for managing replicated files in the face of network partitioning due to site or communication link failures. In this paper, we consider the popular voting scheme along with three enhancements: voting with a primary site, dynamic voting, and dynamic voting with linearly ordered copiee. We develop a stochastic(More)
In a voting-based algorithm, a replicated file can be updated in a partition if it contains a majority of copies. In this paper, we propose an extension of this scheme which permits a file to be updated in a partition provided it contains a majority of up-to-date copies. Our scheme not only preserves mutual consistency of the replicated file, but provides(More)
Games with imperfect information are an interesting and important class of games. They include most card games (e.g., bridge and poker), as well as many economic and political models. Here, we investigate algorithms for solving imperfect information games expressed in their extensive (game-tree) form. In particular, we consider algorithms for the simplest(More)
An information set in a game tree is a set of nodes from which the rules of the game require that the same alternative (i.e., move) be selected. Thus the nodes an information set are indistinguishable to the player moving from that set, thereby reflecting imperfect information, that is, information hidden from that player. Information sets arise naturally(More)