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Directed Hypergraphs And Applications
, 1992
"... We deal with directed hypergraphs as a tool to model and solve some classes of problems arising in Operations Research and in Computer Science. Concepts such as connectivity, paths and cuts are defined. An extension of the main duality results to a special class of hypergraphs is presented. Algorith ..."
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Cited by 100 (5 self)
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We deal with directed hypergraphs as a tool to model and solve some classes of problems arising in Operations Research and in Computer Science. Concepts such as connectivity, paths and cuts are defined. An extension of the main duality results to a special class of hypergraphs is presented. Algorithms to perform visits of hypergraphs and to find optimal paths are studied in detail. Some applications arising in propositional logic, AndOr graphs, relational data bases and transportation analysis are presented. January 1990 Revised, October 1992 ( * ) This research has been supported in part by the "Comitato Nazionale Scienza e Tecnologia dell'Informazione", National Research Council of Italy, under Grant n.89.00208.12, and in part by research grants from the National Research Council of Canada. 1 Dipartimento di Informatica, Università di Pisa, Italy 2 Département d'Informatique et de Recherche Opérationnelle, Université de Montréal, Canada 2 INTRODUCTION Hypergraphs, a generaliz...
Hypergraph Models And Algorithms For The Assembly Problem
, 1992
"... We consider the problem of finding an optimal set of feasible assembly operations in order to derive a desired product from a given set of parts. We show that optimal solutions, under different objective functions, can be obtained by means of computationally efficient hypergraph algorithms. In parti ..."
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Cited by 7 (1 self)
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We consider the problem of finding an optimal set of feasible assembly operations in order to derive a desired product from a given set of parts. We show that optimal solutions, under different objective functions, can be obtained by means of computationally efficient hypergraph algorithms. In particular, we consider the case in which one wants to minimize the duration with an unlimited degree of parallelism. Finally, a new fast algorithm is presented in order to assign operations to robots in an optimal way when the degree of parallelism is bounded. Technical Report TR6/92 March, 1992 (revised: July, 1992) This research has been supported by "Ministero dell'Universit e della Ricerca Scientifica e Tecnologica", National Project on "Gestione dei flussi nei sistemi flessibili di produzione". 2 Introduction In robotic assembly systems, one or more types of items are produced by assembling together several parts given in input, according to a properly defined assembly plan. An asse...
The Satisfiability problem for the SchöenfinkelBernays fragment: Partial Instantiation and Hypergraph Algorithms
 Proceedings of 8th subcommission "Magnetic
, 1994
"... A partial instantiation approach to the solution of the satisfiability problem in the SchoenfinkelBernays fragment of 1 st order logic is presented. It is based on a reduction of the problem to a finite sequence of satisfiability problems in the propositional logic and it improves upon the ori ..."
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Cited by 4 (2 self)
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A partial instantiation approach to the solution of the satisfiability problem in the SchoenfinkelBernays fragment of 1 st order logic is presented. It is based on a reduction of the problem to a finite sequence of satisfiability problems in the propositional logic and it improves upon the original idea of partial instantiation, as proposed by Jeroslow. In the second part of the paper a new interpretation of the partial instantiation approach in terms of Directed Hypergraphs is proposed and a particular implementation for the Datalog case is described in detail. 1 Introduction. The problem of Logical Inference plays a fundamental role in Decision Sciences and has several applications in fields such as decision support systems, logic circuit design, data bases, and programming languages. Although classical approaches to formalize and solve inference problems have been of symbolic nature, in the last few years many scientists in the Operations Research community have studied ...