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21
Scheduling Garbage Collection in Embedded Systems
, 1998
"... The complexity of systems for automatic control and other safetycritical applications grows rapidly. Computer software represents an increasing part of the complexity. As larger systems are developed, we need to find scalable techniques to manage the complexity in order to guarantee high product qu ..."
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The complexity of systems for automatic control and other safetycritical applications grows rapidly. Computer software represents an increasing part of the complexity. As larger systems are developed, we need to find scalable techniques to manage the complexity in order to guarantee high product quality. Memory management is a key quality factor for these systems. Automatic memory management, or garbage collection, is a technique that significantly reduces the complex problem of correct memory management. The risk of software errors decreases and development time is reduced. Garbage collection techniques suitable for interactive and soft realtime systems exist, but few approaches are suitable for systems with hard realtime requirements, such as control systems (embedded systems). One part of the problem is solved by incremental garbage collection algorithms, which have been presented before. We focus on the scheduling problem which forms the second part of the problem, i.e. how the work of a garbage collector should be scheduled in order
Coverage Preserving Reduction Strategies for Reachability Analysis
"... We study the effect of three new reduction strategies for conventional reachability analysis, as used in automated protocol validation algorithms. The first two strategies are implementations of partial order semantics rules that attempt to minimize the number of execution sequences that need to be ..."
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Cited by 60 (8 self)
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We study the effect of three new reduction strategies for conventional reachability analysis, as used in automated protocol validation algorithms. The first two strategies are implementations of partial order semantics rules that attempt to minimize the number of execution sequences that need to be explored for a full state space exploration. The third strategy is the implementation of a state compression scheme that attempts to minimize the amount of memory that is used to built a state space. The three strategies are shown to have a potential for substantially improving the performance of a conventional search. The paper discusses the optimal choices for reducing either run time or memory requirements by four to six times. The strategies can readily be combined with each other and with alternative state space reduction techniques such as supertrace or state space caching methods.
State Compression in SPIN: Recursive Indexing And Compression Training Runs
 IN PROCEEDINGS OF THIRD INTERNATIONAL SPIN WORKSHOP
, 1997
"... The verification algorithm of SPIN is based on an explicit enumeration of a subset of the reachable statespace of a system that is obtained through the formalization of a correctness requirement as an automaton. This automaton restricts the statespace to precisely the subset that may contain ..."
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Cited by 47 (1 self)
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The verification algorithm of SPIN is based on an explicit enumeration of a subset of the reachable statespace of a system that is obtained through the formalization of a correctness requirement as an automaton. This automaton restricts the statespace to precisely the subset that may contain the counterexamples to the original correctness requirement, if they exist. This method of verification conforms to the method for automatatheoretic verification outlined in [VW86]. SPIN derives
Pursuit and evasion from a distance: algorithms and bounds
"... Cops and Robber is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robber, distance k Cops and Robber, where the cops win if they are distance at most k from the robber in G. The cop number of a graph G is the minimum number of cops ..."
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Cited by 11 (5 self)
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Cops and Robber is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robber, distance k Cops and Robber, where the cops win if they are distance at most k from the robber in G. The cop number of a graph G is the minimum number of cops needed to capture the robber in G. The distance k analogue of the cop number, written ck(G), equals the minimum number of cops needed to win at a given distance k. We supply a classification result for graphs with bounded ck(G) values and develop an O(n2s+3) algorithm for determining if ck(G) ≤ s. In the case k = 0, our algorithm is faster than previously known algorithms. Upper and lower bounds are found for ck(G) in terms of the order of G. We prove that
The Complexity of Automated Reasoning
, 1989
"... This thesis explores the relative complexity of proofs produced by the automatic theorem proving procedures of analytic tableaux, linear resolution, the connection method, tree resolution and the DavisPutnam procedure. It is shown that tree resolution simulates the improved tableau procedure and th ..."
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Cited by 8 (0 self)
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This thesis explores the relative complexity of proofs produced by the automatic theorem proving procedures of analytic tableaux, linear resolution, the connection method, tree resolution and the DavisPutnam procedure. It is shown that tree resolution simulates the improved tableau procedure and that SLresolution and the connection method are equivalent to restrictions of the improved tableau method. The theorem by Tseitin that the DavisPutnam Procedure cannot be simulated by tree resolution is given an explicit and simplified proof. The hard examples for tree resolution are contradictions constructed from simple Tseitin graphs.
Enumeration de permutations a motifs exclus
 In Seminaire Lotharingien de Combinatoire (Gerol
, 1993
"... De nombreux auteurs se sont intéressés a ̀ l’énumération de permutations dont certains motifs (sousmots) sont exclus. En particulier, D.E. Knuth [7], considérant l’ensemble des permutations triables par passage dans une pile, a montre ́ qu’elles correspondaient a ̀ l’ensemble des permutation ..."
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De nombreux auteurs se sont intéressés a ̀ l’énumération de permutations dont certains motifs (sousmots) sont exclus. En particulier, D.E. Knuth [7], considérant l’ensemble des permutations triables par passage dans une pile, a montre ́ qu’elles correspondaient a ̀ l’ensemble des permutations ne possédant pas de soussuite de type 231, c’est a ̀ dire de soussuite formée des éléments j, k, i tels que i < j < k (ensemble que l’on notera Sn(231)). Il montre que le nombre de permutations de Sn(231) est donne ́ par le n ième nombre de Catalan. J. West [14] s’est intéresse ́ au problème des permutations triables par deux passages consécutifs dans une pile en imposant une règle du jeu de type “tour de Hanöı ” pour les empilements (c’est a ̀ dire qu’on ne peut empiler un élément j sur un élément i en sommet de pile lorsque i < j), problème différent de la généralisation considérée par D.E. Knuth [7] qui n’imposait aucun type de contrainte. J. West a caractérise ́ ces permutations en termes de permutations a ̀ motifs exclus; les motifs interdits sont 2341 et 3241, ce dernier motif étant autorise ́ dans le cas ou ̀ il est lui même soussuite du motif 35241 dans la permutation (ensemble note ́ Sn(2341, 35241)).
Problem Solving Environments and Symbolic Computing
, 1997
"... ion, representation, communication : : : : : : : : : : 29 5.5 System and human interface design issues : : : : : : : : : : : 31 5.6 Miscellany : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 32 6 Acknowledgments 33 Abstract What role should be played by symbolic mathematical computation ..."
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Cited by 2 (0 self)
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ion, representation, communication : : : : : : : : : : 29 5.5 System and human interface design issues : : : : : : : : : : : 31 5.6 Miscellany : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 32 6 Acknowledgments 33 Abstract What role should be played by symbolic mathematical computation facilities in scientific and engineering "problem solving environments"? Most observers agree with us that in conjunction with numerical libraries and other facilities, symbolic computation should be useful for the creation and manipulation of mathematical models, the production of custom numerical software, and the solution of certains classes of mathematical problems that are difficult to handle by traditional floatingpoint computation. Even further, though, symbolic representation and manipulation can potentially play a more central role  with more general representations a program can naturally deal with computational objects of a more general nature. Numerical, graphical, and other...
Periodicities on Trees
, 1995
"... We introduce the notion of periodicity for kary labeled trees: roughly speaking, a tree is periodic if it can be obtained by a sequence of concatenations of a smaller tree plus a "remainder". The period is the shape of such smaller tree (i.e. the corresponding unlabeled tree). This defini ..."
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We introduce the notion of periodicity for kary labeled trees: roughly speaking, a tree is periodic if it can be obtained by a sequence of concatenations of a smaller tree plus a "remainder". The period is the shape of such smaller tree (i.e. the corresponding unlabeled tree). This definition reduces to the classical one for string when restricted to the case of unary trees. Then, we define the greatest common divisor of two unlabeled trees and relate right congruences to unlabeled trees. This allows us to give a characterization of tree periodicity in terms of right congruences and then to prove a periodicity theorem for trees that is a generalization to trees of the Fine and Wilf's periodicity theorem for words. Keywords: Congruence, periodicity, labeled tree. Work partially supported by the ESPRIT II Basic Research Actions Program of the EC under Project ASMICS 2 (contract No. 6317) and in part by the Italian Ministry of Universities and Scientific Research MURST 40% Algoritmi, ...
Cops and robbers from a distance
 Theor. Comput. Sci
"... Abstract. Cops and Robbers is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robbers, distance k Cops and Robbers, where the cops win if at least one of them is of distance at most k from the robber in G. The cop number of a graph G ..."
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Abstract. Cops and Robbers is a pursuit and evasion game played on graphs that has received much attention. We consider an extension of Cops and Robbers, distance k Cops and Robbers, where the cops win if at least one of them is of distance at most k from the robber in G. The cop number of a graph G is the minimum number of cops needed to capture the robber in G. The distance k analogue of the cop number, written ck(G), equals the minimum number of cops needed to win at a given distance k. We study the parameter ck from algorithmic, structural, and probabilistic perspectives. We supply a classification result for graphs with bounded ck(G) values and develop an O(n2s+3) algorithm for determining if ck(G) ≤ s for s fixed. We prove that if s is not fixed, then computing ck(G) is NPhard. Upper and lower bounds are found for ck(G) in terms of the order of G. We prove that n