Showing papers in "Theoretical Computer Science in 2012"

TL;DR: It is shown that this well-known problem is NP-hard even for instances in the plane, answering an open question posed by Dasgupta (2007).

TL;DR: This paper proposes the first attribute-based encryption (ABE) schemes allowing for truly expressive access structures and with constant ciphertext size and describes a new efficient identity-based revocation mechanism that gives rise to the most expressive KP-ABE realization with constant-size ciphertexts.

TL;DR: General investigations for finite @m are presented, a limit result for @m going to infinity is derived in terms of a density of points and lower bounds for placing the reference point to guarantee the Pareto front's extreme points in an optimal @m-distribution are derived.

TL;DR: It is proved that independent set reconfigurability in perfect graphs (under any of the three models) generalizes the shortest path reconfigURability problem in general graphs and is therefore PSPACE-complete.

TL;DR: This paper presents the first approach to the automatic cost analysis of object-oriented bytecode programs, and reports on COSTA, an implementation for Java bytecode which can obtain upper bounds on cost for a large class of programs and complexity classes.

TL;DR: This theorem shows that for problems such as arithmetic circuit lower bounds or black-box derandomization of identity testing, the case of depth four circuits is in a certain sense the general case.

TL;DR: In this paper, it was shown that exponential memory is sufficient and may be necessary for winning strategies in energy parity games, and that the problem of deciding the winner in such games can be solved in polynomial time in NP? coNP.

TL;DR: In this article, the authors analyzed the role of population in EAs and showed rigorously that large populations may not always be useful and the conditions under which large populations can be harmful.

TL;DR: This paper investigates two classes of one-dimensional bin packing algorithms, and better lower bounds for their asymptotic worst-case behavior are given, and the parametric case is investigated as well.

TL;DR: This study shows that the 2-extraconnectivity of a k-ary n-cube Q"n^k for k>=4 and n>=5 is equal to 6n-5.

TL;DR: In this article, the authors show how to use wavelet trees to solve fundamental algorithmic problems such as range quantile queries, range next value queries, and range intersection queries.

TL;DR: This is the first theoretical analysis proving the usefulness of crossover for a non-artificial problem, and shows that a natural evolutionary algorithm for the all-pairs shortest path problem is significantly faster with a crossover operator than without.

TL;DR: The notion of compact multiple alignment is introduced, which allows us to link these theories to the problem of summarizing under time warping and to use a genetic algorithm based on a specific representation of the genotype inspired by genes to consistently paint the fitness landscape.

TL;DR: It is proved that for arbitrarily given @e,@d>0 it calculates a solution with contribution at most (1+@e) times the minimal contribution with probability at least (1-@d).

TL;DR: This paper presents linear-time algorithms for computing all the strong bridges and all theStrong articulation points of directed graphs, solving an open problem posed in Beldiceanu et al. (2005).

TL;DR: It is obtained that an n-dimension balanced hypercube BH"n has the matching preclusion number 2n, and it is mainly proved that for the balancedhypercube B H"n, each matchingPreclusion set of cardinality 2n is trivial, and the conditional matching preclusions number of balanced hyper cube is 4n-2 whenever n>=2.

TL;DR: The speed of convergence on deterministic best-response walks in selfish routing games and cut games is studied and it is proved that starting from an arbitrary configuration, after one round of best responses of players, the resulting configuration is a @Q(n)-approximate solution.

TL;DR: This article presents a language independent theory of product line refinement, establishing refinement properties that justify stepwise and compositional product line evolution.

TL;DR: This paper proposes two secure, efficient, and verifiable multi-secret sharing schemes, namely Scheme-I and Scheme-II, based on the Lagrange interpolating polynomial and the LFSR-based public key cryptosystem.

TL;DR: This work shows how fluid-approximation techniques may be used to extract passage-time measures from performance models, focusing on two types of passage measure: passage times involving individual components, as well as passage times which capture the time taken for a population of components to evolve.

TL;DR: A complete complexity classification of (precoloring extension of) 3-Coloring for H-free graphs when H is a fixed graph on at most 6 vertices: the problem is polynomial-time solvable if H is an linear forest; otherwise it is NP-complete.

TL;DR: This paper first shows that this problem is NP-hard by a reduction from Exact 3-Cover, and presents a parameterized algorithm based on a refined search tree technique with a running time of O(4.612^k+|V|^4^.^5), which improves the trivial algorithm of running time O(6^k+.

TL;DR: It is shown that L-weighted automata, L-rational series, and L-valued monadic second order logic have the same expressive power, for any bounded lattice L and for finite and infinite words.

TL;DR: This paper proves that a proposed quotienting that also preserves the stochastic semantics and that is complete in the sense that the semantics of individual species can be recovered from the aggregate semantics yields a sufficient condition for weak lumpability.

TL;DR: In this article, the problem of succinctly representing an arbitrary permutation on {0,...,n-1} so that it can be computed quickly for any i and any (positive or negative) integer power k was investigated.

TL;DR: This paper presents an efficient method for computing the minimal absent words of bounded length using a trie of bounded depth, representing bounded length factors, and provides a linear-time algorithm with less memory usage than previous solutions.

TL;DR: It is proved that k-SPC is NP-complete, the problem of the set of parameterized k-covers which combines k-cover measure with parameterized matching, which is a distance measure for strings.

TL;DR: An improved lower bound is developed showing that no deterministic semi-online algorithm can attain a competitive ratio smaller than 1.585, which significantly reduces the gap between the previous lower bound and the upper bound of 1.6.

TL;DR: The paper investigates formal properties of reaction systems introduced by Ehrenfeucht and Rozenberg, and introduces and characterize the property of functional completeness.

TL;DR: A definition of security against chosen ciphertext attacks for C-PRES schemes with keyword anonymity, which combines C-PRE and PEKS is proposed, and a scheme that satisfies the definition is presented.