Showing papers in "Theoretical Computer Science in 1999"

TL;DR: The class of event-clock automata, which contain both event-recording and event-predicting clocks, is a suitable specification language for real-time properties and an algorithm for checking if a timed automaton meets a specification that is given as an event- clock automaton is provided.

TL;DR: It is proved the worst-case upper bound 1.5045..

TL;DR: This paper introduces a special subclass of TAGs and develops a fast parsing algorithm for the subclass, together with some of its language theoretic characterizations, and develops and demonstrates the effectiveness of the system by presenting some experimental results obtained from biological data.

TL;DR: In this article, a simple abstract framework is proposed to classify and compare constraint propagation algorithms and to establish their basic properties, including consistency, consistency enforcing, Waltz, filtering or narrowing.

TL;DR: Another tree reconstruction method, the witness-antiwitness method (WAM), is presented, which is faster than DCM, especially on random trees, and converges to the true tree topology at the same rate as DCM.

TL;DR: It is proved that rectangular hybrid automata have finite bisimilarity quotients when all control transitions happen at integer times, even if the constraints on the derivatives of the variables vary between control states.

TL;DR: A selective survey of numerical representations of preference structures from the perspective of the representational theory of measurement, then describes recent contributions to ordinal, additive, and expected utility theories.

TL;DR: A variant of Fine and Wilf's theorem for partial words is proved, and extensions of some general combinatorial properties of words are given.

TL;DR: The notion of bisimulation as proposed by Larsen and Skou for discrete probabilistic transition systems is shown to coincide with a coalgebraic definition in the sense of Aczel and Mendier in terms of a set functor, which makes it possible to generalize the concepts to a continuous setting involving Borel probability measures.

TL;DR: The language and framework of Type 2 Theory of Effectivity (TTE) is used which supplies a concise language for distinguishing a variety of effectivity properties and which admits highly effective versions of classical theorems.

TL;DR: An analytical model for the dynamics of a mutation-only genetic algorithm is introduced that identifies a new and general mechanism causing metastability in evolutionary dynamics and shows how finite populations induce metastability, even in regions where fitness does not exhibit a local optimum.

TL;DR: The most general and most expressive class of systems in this hierarchy is called process rewrite systems (PRS), which subsume Petri nets, PA-processes, and pushdown processes and are strictly more expressive than any of these.

TL;DR: It is proved that computing the median string corresponds to a NP-complete decision problems, thus proving that this problem is NP-hard.

TL;DR: The mathematical theory of a simple knowledge acquisition procedure based on implications and counter examples is given, and examples of application are shown.

TL;DR: This work proves that CQDDs allow to compute the exact effect of the repeated execution of any fixed cycle in the transition graph of a system and defines a generic reachability analysis semi-algorithm parametrized by a set of cycles Θ.

TL;DR: The method developed extends the range of applicability of singularity analysis techniques to combinatorial sums involving transcendental elements like logarithms or fractional powers.

TL;DR: It is shown that if the target of the translation is taken to be an affine calculus, where! controls contraction but weakening is allowed everywhere, then the second translation corresponds to a call-by-need calculus, as recently defined by Ariola, Felleisen, Maraist, Odersky and Wadler.

TL;DR: The existence of a morphism that generates the palindromes of any infinite Sturmian word generated by a Morphism is proved.

TL;DR: This work studies sorting of signed permutations by reversals and transpositions, a problem which adequately models genome rearrangements, as the genes in DNA are oriented, and establishes a lower bound and gives a 2-approximation algorithm for the problem.

TL;DR: It is shown that, even though this problem can be solved using a natural extension of failure detector ♢ L, such solutions are not quiescent — in other words,♢ L alone is not sufficient to achieve quyingcent consensus in partitionable networks.

TL;DR: A very simple linear time testing algorithm based only on a depth-first search tree that produces explicit Kuratowski's subgraphs when the given graph is not planar and a graph-reduction technique is adopted so that the embeddings for the planar biconnected components constructed at each iteration never have to be changed.

TL;DR: It is proved that a restricted version of the pquasi complete graph problem (given a positive integer k, whether a graph contains a 0.5-quasicomplete subgraph of which size >k or not) is NP-complete.

TL;DR: The studies show that two transitions not causally related may however occur in a fixed ordering in any computation, i.e., the π-calculus may implicitly express a precedence between actions.

TL;DR: It is shown that in the combinatorics of finite words two parameters play an essential role and a new characterization in terms of special factors and of R and K is given for the set PER of all words w having two periods p and q which are coprimes and such that ¦w¦ = p + q − 2.

TL;DR: It is shown closed-form analytic functions consisting of a finite number of trigonometric terms can simulate Turing machines, with exponential slowdown in one dimension or in real time in two or more.

TL;DR: In this article, the authors present a series of encodings for languages with (1) input-guarded choice, (2) both input-and outputguarded choices, and (3) mixed-guarding choice, and investigate them with respect to compositionality and divergencefreedom.

TL;DR: This paper introduces a general framework that includes many Petri net models, present in the literature, which differ from one another with respect to timing location, timing strength and time domain, and introduces an operational semantics that takes into account both sequentialization and timing of actions.

TL;DR: The most important questions, research topics and technical tools used in various branches of evolutionary algorithms are considered and a road map is given to facilitate the readers’ orientation in evolutionary computation theory.

TL;DR: Two ways of implementing Krivine's abstract machine, which stands in a relation which can be accurately described using the call/return symmetry discovered by Asperti and Laneve, are compared.

TL;DR: The convergence rates of genetic algorithms are discussed by using the minorization condition in the Markov chain theory to obtain the bound on its convergence rate on the general state space and on the finite state space.