http://biblioteca.universia.net/verColeccion.do?id=8483 Mostrando recursos 1 - 20 de 9,277 es http://biblioteca.universia.net/img/logotipo.jpg http://biblioteca.universia.net/ http://biblioteca.universia.net/ficha.do?id=20740262 The author presents two tricks to accelerate depth-first search algorithms for a class of combinatorial puzzle problems, such as tiling a tray by a fixed set of polyominoes. The first trick is to implement each assumption of the search with reversible local operations on doubly linked lists. By this trick, every step of the search affects the data incrementally. The second trick is to add a ghost square that represents the identity of each polyomino. Thus puts the rule that each polyomino b... Knuth, Donald E. http://biblioteca.universia.net/ficha.do?id=20740995 Madhu Sudan's work spans many areas of computer science theory including computational complexity theory, the design of efficient algorithms, algorithmic coding theory, and the theory of program checking and correcting. Two results of Sudan stand out in the impact they have had on the mathematics of computation. The first work shows a probabilistic characterization of the class NP -- those sets for which short and easily checkable proofs of membership exist, and demonstrates consequences of... Goldwasser, Shafi http://biblioteca.universia.net/ficha.do?id=20741681 This paper proposes a signature scheme where the signatures are generated by the cooperation of a number of people from a given group of senders and the signatures are verified by a certain number of people from the group of recipients. Shamir's threshold scheme and Schnorr's signature scheme are used to realize the proposed scheme. lal, Sunder; Kumar, Manoj http://biblioteca.universia.net/ficha.do?id=20741700 In this paper, we propose a Directed Threshold Multi-Signature Scheme. In this threshold signature scheme, any malicious set of signers cannot impersonate any other set of signers to forge the signatures. In case of forgery, it is possible to trace the signing set. This threshold signature scheme is applicable when the message is sensitive to the signature receiver; and the signatures are generated by the cooperation of a number of people from a given group of senders. lal, Sunder; Kumar, Manoj http://biblioteca.universia.net/ficha.do?id=20741750 Directed signature is the solution of such problems when the signed message contains information sensitive to the signature receiver. Generally, in many application of directed signature, the signer is generally a single person. But when the message is on behalf of an organization, a valid sensitive message may require the approval of several people. Threshold signature schemes are used to solve these problems. This paper presents a threshold directed signature scheme. Lal, Sunder; Kumar, Manoj http://biblioteca.universia.net/ficha.do?id=20741751 We prove several results about the relations between injectivity and surjectivity for sand automata. Moreover, we begin the exploration of the dynamical behavior of sand automata proving that the property of nilpotency is undecidable. We believe that the proof technique used for this last result might reveal useful for many other results in this context. Cervelle, Julien; Formenti, Enrico; Masson, Benoit http://biblioteca.universia.net/ficha.do?id=20741752 We propose a new simple \emph{trace} logic that can be used to specify \emph{local security properties}, i.e. security properties that refer to a single participant of the protocol specification. Our technique allows a protocol designer to provide a formal specification of the desired security properties, and integrate it naturally into the design process of cryptographic protocols. Furthermore, the logic can be used for formal verification. We illustrate the utility of our technique by expos... Corin, Ricardo; Durante, Antonio; Etalle, Sandro; Hartel, Pieter http://biblioteca.universia.net/ficha.do?id=20741753 There is a growing interest in discovery of internet topology at the interface level. A new generation of highly distributed measurement systems is currently being deployed. Unfortunately, the research community has not examined the problem of how to perform such measurements efficiently and in a network-friendly manner. In this paper we make two contributions toward that end. First, we show that standard topology discovery methods (e.g., skitter) are quite inefficient, repeatedly probing the... Donnet, Benoit; Raoult, Philippe; Friedman, Timur; Crovella, Mark http://biblioteca.universia.net/ficha.do?id=20741754 The paper is an attempt to generalize a methodology, which is similar to the bounded-input bounded-output method currently widely used for the system stability studies. The presented earlier methodology allows decomposition of input space into bounded subspaces and defining for each subspace its bounding surface. It also defines a corresponding predefined control, which maps any point of a bounded input into a desired bounded output subspace. This methodology was improved by providing a mecha... Flikop, Ziny http://biblioteca.universia.net/ficha.do?id=20741755 The most advanced implementation of adaptive constraint processing with Constraint Handling Rules (CHR) allows the application of intelligent search strategies to solve Constraint Satisfaction Problems (CSP). This presentation compares an improved version of conflict-directed backjumping and two variants of dynamic backtracking with respect to chronological backtracking on some of the AIM instances which are a benchmark set of random 3-SAT problems. A CHR implementation of a Boolean constrain... Wolf, Armin http://biblioteca.universia.net/ficha.do?id=20741756 Wireless LANs have achieved a tremendous amount of growth in recent years. Among various wireless LAN technologies, the IEEE 802.11b based wireless LAN technology can be cited as the most prominent technology today. Despite being widely deployed, 802.11b cannot be termed as a well matured technology. Although 802.11b is adequate for basic connectivity and packet switching, It is evident that there is ample scope for its improvement in areas like quality of service, fairness, performance, secu... Sharma, Srikant http://biblioteca.universia.net/ficha.do?id=20741757 Modern Ethernet switches support many advanced features beyond route learning and packet forwarding such as VLAN tagging, IGMP snooping, rate limiting, and status monitoring, which can be controlled through a programmatic interface. Traditionally, these features are mostly used to statically configure a network. This paper proposes to apply them as dynamic control mechanisms to maximize physical network link resources, to minimize failure recovery time, to enforce QoS requirements, and to sup... Sharma, Srikant; Chiueh, Tzi-cker http://biblioteca.universia.net/ficha.do?id=20741758 We study conditions for a concurrent construction of proof-nets in the framework developed by Andreoli in recent papers. We define specific correctness criteria for that purpose. We first study closed modules (i.e. validity of the execution of a logic program), then extend the criterion to open modules (i.e. validity during the execution) distinguishing criteria for acyclicity and connectability in order to allow incremental verification. Fouquere, Christophe; Mogbil, Virgile http://biblioteca.universia.net/ficha.do?id=20741759 Chebyshev polynomials have been recently proposed for designing public-key systems. Indeed, they enjoy some nice chaotic properties, which seem to be suitable for use in Cryptography. Moreover, they satisfy a semi-group property, which makes possible implementing a trapdoor mechanism. In this paper we study a public key cryptosystem based on such polynomials, which provides both encryption and digital signature. The cryptosystem works on real numbers and is quite efficient. Unfortunately, fro... Bergamo, Pina; D'Arco, Paolo; De Santis, Alfredo; Kocarev, Ljupco http://biblioteca.universia.net/ficha.do?id=20741760 This article illustrates the use of a logical specification language to capture various forms of confidentiality properties used in the security literature. Pucella, Riccardo http://biblioteca.universia.net/ficha.do?id=20741761 This article introduces three invariance principles under which P is different from NP. In the second part a theorem of convergence is proven. This theorem states that for any language L there exists an infinite sequence of languages from O(n) that converges to L. Moscu, Mircea Alexandru Popescu http://biblioteca.universia.net/ficha.do?id=20741762 Recently, among experiments for realization of quantum computers, NMR quantum computers have achieved the most impressive succession. There is a model of the NMR quantum computation,namely Atsumi and Nishino's bulk quantum Turing Machine. It assumes, however, an unnatural assumption with quantum mechanics. We, then, define a more natural and quantum mechanically realizable modified bulk quantum Turing Machine, and show its computational ability by comparing complexity classes with quantum Tur... Matsui, Tetsushi http://biblioteca.universia.net/ficha.do?id=20741763 Information Technology is emerging to be the technology of 21st century. The paradigm shift from industrial society to information society had already become a reality! It is indeed high time to think about integrating IT in all facets of education -- may it be in secondary level, or be it in reskilling the employed ones. This paper discusses various issues in incorporating IT in various levels of education, and the need to think about a task force to counter the so-called slow down and reces... Shajeemohan, B. S. http://biblioteca.universia.net/ficha.do?id=20741764 Resource sharing within Grid collaborations usually implies specific sharing mechanisms at participating sites. Challenging policy issues can arise within virtual organizations (VOs) that integrate participants and resources spanning multiple physical institutions. Resource owners may wish to grant to one or more VOs the right to use certain resources subject to local policy and service level agreements, and each VO may then wish to use those resources subject to VO policy. Thus, we must addr... Dumitrescu, Catalin; Foster, Ian http://biblioteca.universia.net/ficha.do?id=20741765 Computational grids typically consist of nodes utilizing ordinary processors such as the Intel Pentium. Field Programmable Gate Arrays (FPGAs) are able to perform certain compute-intensive tasks very well due to their inherent parallel architecture, often resulting in orders of magnitude speedups. This paper explores how FPGAs can be transparently exposed for remote use via grid services, by integrating the Proteus Software Platform with the Globus Toolkit 3.0. Nathan, Darran; Clemens, Ralf