Showing papers in "Journal of Computer and System Sciences in 2011"

TL;DR: There is no reduction from OR-SAT to any set A where the length of the output is bounded by a polynomial in n, unless NP@?coNP/poly, and the Polynomial-Time Hierarchy collapses.

TL;DR: It is suggested that the considerable intellectual effort needed for designing efficient algorithms for multi-core architectures may be most fruitfully expended in designing portable algorithms, once and for all, for such a bridging model.

TL;DR: This analysis bridges the gap between the axiomatic and the constructive approaches to defining QCA by showing that under these conditions the operator U can be implemented locally; i.e. put into the form of a quantum circuit made up with more elementary operators - each acting solely upon neighboring nodes.

TL;DR: An adaptive clustering protocol for wireless sensor networks is introduced, which is called Adaptive Decentralized Re-Clustering Protocol (ADRP) for Wireless Sensor Networks, where the cluster heads and next heads are elected based on residual energy of each node and the averageEnergy of each cluster.

TL;DR: A new theory of equivalence of processes is proposed which allows the identification of systems that have the same context-aware behaviours and it is proved that CCA encodes the @p-calculus which is known to be a universal model of computation.

TL;DR: This paper gives an extensive picture of tractable and intractable instances of the problem of finding occurrences of motifs in vertex-colored graphs, where a motif is a multiset of colors, and an occurrence is a subset of connected vertices whose multisets of colors equals the motif.

TL;DR: D deterministic extractors are given for sources generated in small space, where space s sources on {0,1}^n as sources generated by width 2^s branching programs.

TL;DR: A method to process range search queries efficiently and accurately by partitioning the road networks to some special polygons based on the Voronoi diagram is proposed and the empirical experiments show that VRS and VCR surpass all their rivals for both static and moving queries.

TL;DR: The theory of holographic algorithms is developed, d-admissibility and d-realizability for general signatures are defined, and some general constructions of admissible and realizable families are given.

TL;DR: The complexity of the original, unbounded depth Minimum Equivalent Expression problem, by showing that the depth-k version is @S"2^P-complete under Turing reductions for all k>=3, is settled.

TL;DR: Two energy allocation schemes are described, based on time-slots, which aim at optimum use of the periodically harvested solar energy, while minimizing the variability in energy allocation, for resource-constrained sensors.

TL;DR: This paper reports on assessing and improving complex system resilience using distributed redundancy, termed degeneracy in biological systems, to endow large-scale complicated computer systems with the same robustness that emerges in complex biological and natural systems.

TL;DR: A new approach for establishing fixed-parameter tractability of problems parameterized above tight lower bounds or below tight upper bounds is introduced and a new probabilistic inequality is obtained that is dual to the Hypercontractive Inequality.

TL;DR: A novel Secure Multiparty Computation (SMC)-based privacy preserving OLAP framework for distributed collections of XML documents is proposed, which has many novel features ranging from nice theoretical properties to an effective and efficient protocol, called Secure Distributed OLAP aggregation protocol (SDO).

TL;DR: In this article, a linear vertex kernel for the k-feedback arc set in Tournaments (k-FAST) problem was obtained, and a polynomial time algorithm was given to obtain an equivalent instance with at most (2+@e)k vertices.

TL;DR: A notion of a partial representation for views is described, and it is shown that, once computed and stored, this partial representation can be used to answer subsequent queries on the probabilistic databases.

TL;DR: In this article, the authors generalize the Nemhauser-trotter local optimization theorem to vertex deletion problems and introduce a new algorithm based on purely combinatorial arguments.

TL;DR: The complexity of containment and satisfiability of conjunctive queries over finite, unranked, labeled trees is studied with respect to the axes Child, NextSibling, their transitive and reflexive closures, and Following.

TL;DR: It is shown that the induced matching problem on planar graphs has a kernel of size at most 40k that is computable in linear time; this significantly improves the results of Moser and Sikdar (2007) and can be applied to the area of parameterized computation.

TL;DR: This work proves lower bounds for several old and new subclasses of circuits: monotone circuits, orthogonal formulas, non-canceling formulas, and noise-resistant formulas with explicit map that has exponentially small discrepancy for every partition of the input variables into two sets of roughly the same size.

TL;DR: This work studies the properties of other measures that arise naturally in this framework and introduces yet more notions of resource-bounded Kolmogorov complexity, to demonstrate that other complexity measures such as branching-program size and formula size can also be discussed in terms of Kolmogsorv complexity.

TL;DR: It is shown that if the input objects of generally intractable problems exhibit a sufficiently high degree of similarity between each other on average, then there are efficient exact solving algorithms for these median problems.

TL;DR: Normalized information distance (NID) as discussed by the authors uses the theoretical notion of Kolmogorov complexity, which is approximated by the length of the compressed version of the file involved, using a real-world compression program.

TL;DR: A strategy to perform peer-to-peer-inspired meta-scheduling in Grids that demonstrates scalability, making it suitable for many scientific applications that require resources on a large scale.

TL;DR: The approach used, to show that various partial covering problems in graphs in the realm of parameterized complexity are fixed parameter tractable on planar graphs, graphs of bounded local treewidth and graph excluding some graph as a minor, is quite different from previously known techniques.

TL;DR: A framework for discovering and classifying the vast amount of service information present in the digital health ecosystems is presented, which incorporates the technology of semantic focused crawler and social classification.

TL;DR: It is shown that for every integer @?

TL;DR: In this article, it was shown that the problem of finding a tree t-spanner of treewidth at most k in a given planar graph G is fixed parameter tractable parameterized by k and t, and for every fixed t and k, the running time of their algorithm is linear.

TL;DR: This research aims at designing an environment that allows the visitor to freely select any interested exhibit and instantly share his/her note or remark about the exhibit with others through the Internet.

TL;DR: It is shown that it is NP-hard to approximate the bandwidth within any constant, and that an approximation ratio of clogn/loglogn will imply a quasi-polynomial time algorithm for NP (when c is a sufficiently small constant).