Mostrando recursos 161 - 180 de 188,281


    Daniel J. Pless; George F. Luger; Daniel Pless; Chayan Chakrabarti; Roshan Rammohan; George F. Luger
    We have created a logic-based Turing-complete language for stochastic modeling. Since the inference scheme for this language is based on a variant of Pearl’s loopy belief propagation algorithm, we call it Loopy Logic. Traditional Bayesian Networks have limited expressive power, basically constrained to finite domains as in the propositional calculus. This language contains variables that can capture general classes of situations, events, and relationships. A first-order language is able to reason about potentially infinite classes and situations such as hidden Markov models(HMMs). The language uses an Expectation-Maximization (EM) type learning of parameters. This has a natural fit with the Loopy...


    Meriel Huggard
    This paper describes the restructuring of a second year logic course at Trinity College, Dublin. The course aims to develop student skills in the propositional and predicate calculi and to encourage students to exercise these skills in applications that arise in computer science and discrete mathematics. This paper details how the teaching methods used for this course were realigned with these aims. The restructured course is being delivered for the first time in 2002 and its outcomes will be reported on in detail at the Conference in July. 1

  3. Toward discourse representation via pregroup grammars

    Anne Preller
    Every pregroup grammar is shown to be strongly equivalent to one which uses basic types and left and right adjoints of basic types only. Therefore a semantical interpretation is independent of the order of the associated logic. Lexical entries are read as expressions in a two sorted predicate logic with ∈ and functional symbols. The parsing of a sentence defines a substitution that combines the expressions associated to the individual words. The resulting variable free formula is the translation of the sentence. It can be computed in time proportional to the parsing structure. Non-logical axioms are associated to certain words...

  4. A Hardware NIC Scheduler to Guarantee QoS on High Performance Servers *

    J. M. Claver; M. Canseco; P. Agustí; G. León
    Abstract. In this paper we present the architecture and implementation of a hardware NIC scheduler to guarantee QoS on servers for high speed LAN/SAN. Our proposal employs a programmable logic device based on an FPGA in order to store and update connection states, and to decide what data stream is to be sent next. The network architecture is connection-oriented and reliable, based on credit flow control. The architecture scales from 4 to 32 streams using a Xilinx Virtex 2000E. It supports links with speeds in the order of Gbps while, maintaining the delay and jitter constrains for the QoS streams....

  5. Operational Risk Management: How an I- DSS may help

    Pedro A. C. Sousa; João Paulo Pimentão; Rita Almeida Ribeiro
    Management, needs intelligent tools to implement Comprehensive Emergency Management Programs. In this paper we discuss how an Intelligent Decision Support System (I-DSS), based on Fuzzy Logic, can be used for supporting the management of complex and critical systems, especially under contingency situations, with limited resources ’ availability. This I-DSS is a contingency/emergency management tool and its objectives are: to help users make good decisions under critical and stressful situations; to decrease global risk (e.g. prevention); to increase the level of response (e.g. improved reaction through instruction and simulation); and to ensure process description’s consistency analysis.

  6. $rec.titulo

    We study contexts (terms with holes) by proposing a ‘λcalculus with holes’. It is very expressive and can encode programming constructs apparently unrelated to contexts, including objects and algorithms in partial evaluation. We give proofs of confluence, preservation of strong normalisation, principal typing for an ML-style Hindley-Milner type system, and an applicative characterisation of contextual equivalence. We explore the limitations of the calculus including further applications, and discuss how they might be tackled. 1 Categories and Subject Descriptors: F.4.1 [Mathematical Logic and Formal Languages]: lambda calculus and related systems

  7. Logique & Analyse 196 (2006), x–x THE LOGIC OF BEING INFORMED

    Luciano Floridi
    One of the open problems in the philosophy of information is whether there is an information logic (IL), different from epistemic (EL) and doxastic logic (DL), which formalises the relation “a is informed that p ” (Iap) satisfactorily. In this paper, the problem is solved by arguing that the axiom schemata of the normal modal logic (NML) KTB (also known as B or Br or Brouwer’s system) are well suited to formalise the relation of “being informed”. After having shown that IL can be constructed as an informational reading of KTB, four consequences of a KTB-based IL are explored: information...

  8. Connection Tableaux with Lazy Paramodulation

    Andrei Paskevich
    Abstract. It is well-known that the connection refinement of clause tableaux with paramodulation is incomplete (even with weak connections). In this paper, we present a new connection tableau calculus for logic with equality. This calculus is based on a lazy form of paramodulation where parts of the unification step become auxiliary subgoals in a tableau and may be subjected to subsequent paramodulations. Our calculus uses ordering constraints and a certain form of the basicness restriction. 1

  9. Loosely Coupled Traceability for ATL

    Frédéric Jouault
    Abstract. In the context of model transformation, traceability information may be used in a wide variety of scenarios. Each of them potentially requires a different format or complexity level. Moreover, a single transformation program can be used in several contexts. Consequently, such a program may need to be able to generate different kinds of traceability information. This work aims at showing how traceability can be added to programs written in ATLAS Transformation Language while limiting dependencies to program logic. Model transformation is used to implement this approach. 1

  10. Explanation-Based Generalization in a Logic-Programming Environment*

    This paper describes a domain-independent implementation of explanation-based generalization (EBG) within a logic-programming environment. Explanation is interleaved with generalization, so that as the training instance is proven to be a positive example of the goal concept, the generalization is simultaneously created. All aspects of the EBG task are viewed in logic, which provides a clear semantics for EBG, and allows its integration into the logic-programming system. In this light operationally becomes a property requiring explicit reasoning. Additionally, viewing EBG in logic clarifies the relation of learning search-control to EBG, and suggests solutions for dealing with imperfect domain theories.

  11. A logical approach to efficient Max-SAT solving

    Javier Larrosa; Federico Heras; Simon de Givry
    Weighted Max-SAT is the optimization version of SAT and many important problems can be naturally encoded as such. Solving weighted Max-SAT is an important problem from both a theoretical and a practical point of view. In recent years, there has been considerable interest in finding efficient solving techniques. Most of this work focuses on the computation of good quality lower bounds to be used within a branch and bound DPLLlike algorithm. Most often, these lower bounds are described in a procedural way. Because of that, it is difficult to realize the logic that is behind. In this paper we introduce...

  12. Exploring Energy-Performance Trade-offs for Heterogeneous Interconnect Clustered VLIW Processors

    Rahul Nagpal; Y. N. Srikant
    Clustered architecture processors are preferred for embedded systems because centralized register file architectures scale poorly in terms of clock rate, chip area, and power consumption. Although clustering helps by improving clock speed, reducing energy consumption of the logic, and making design simpler, it introduces extra overheads by way of inter-cluster communication. This communication happens over long global wires having high load capacitance which leads to delay in execution and significantly high energy consumption. Technological advancements permit design of a variety of clustered architectures by varying the degree of clustering and the type of interconnects. In this paper, we focus on...

  13. A Causal Theory of Abduction

    Alexander Bochman
    The paper provides a uniform representation of abductive reasoning in the logical framework of causal inference relations. The representation covers in a single framework not only traditional, ‘classical ’ forms of abduction, but also abductive reasoning in diagnosis, theories of actions and change, and abductive logic programming. 1

  14. From intuitionistic topology to point-free topology Pure and Applied Logic Colloquium,

    Erik Palmgren
    1. Constructive continuity When computing the integral, calculating supremum or approximating zeroes of a continuous function f: [0,1] we use its uniform continuity. Using non-constructive axioms, e.g. the Fan Theorem, one can show uniform continuity from pointwise continuity.

  15. Specifying and Verifying Systems of Communicating Agents in a Temporal Action Logic

    Laura Giordano; Alberto Martelli; Camilla Schwind
    Abstract. In this paper we develop a logical framework for specifying and verifying systems of communicating agents. The framework is based on a Dynamic Linear Time Temporal Logic (DLTL). It provides a simple formalization of the communicative actions in terms of their effects and preconditions and the specification of an interaction protocol by means of temporal constraints. We adopt a social approach to agent communication (as proposed by Singh): communication can be described in terms of changes in the social relations between participants, and protocols in terms of creation, manipulation and satisfaction of commitments among agents. The description of the...

  16. On the Properties of Metamodeling in OWL

    Boris Motik
    Abstract. A common practice in conceptual modeling is to separate the intensional from the extensional model. Although very intuitive, this approach is inadequate for many complex domains, where the borderline between the two models is not clear-cut. Therefore, OWL-Full, the most expressive of the Semantic Web ontology languages, allows combining the intensional and the extensional model by a feature we refer to as metamodeling. In this paper, we show that the semantics of metamodeling adopted in OWL-Full leads to undecidability of basic inference problems, due to free mixing of logical and metalogical symbols. Based on this result, we propose two...

  17. CyberCare: Reasoning about Patient’s Profile in Home Healthcare

    Ra Mileo; Davide Merico; Roberto Bisiani
    Abstract. This paper proposes a framework based on modern tools and technologies to enable home healthcare through the observation of i) patient’s clinical details by means of a Wearable Acquisition Device, ii) movements detected by sensors networks and iii) habits/actions inferred by an ASP logic program. 1 Introduction: the social and clinical context In recent years, Communication and Information Technologies have been introduced in specific fields of medical sciences in order to allow the delivery of clinical care. A centralized view of medicine at a distance led to the integration of Communication Technologies and

  18. Computational Templates,  Neural Network Dynamics,  and Symbolic Logic

    Abstract —   This  paper  looks  at  the  relationship  between subsymbolic neural  networks  and  symbolic  logical  systems from a  philosophy  of  science  perspective. More  specifically, the point  of  view  is  that  of  Paul  Humphreys ’  philosophical account of  the  organization  of  scientific  knowledge

  19. Adapting Golog for composition of semantic web Services

    Sheila Mcilraith
    Motivated by the problem of automatically composing network accessible services, such as those on the World Wide Web, this paper proposes an approach to building agent technology based on the notion of generic procedures and customizing user constraint. We argue that an augmented version of the logic programming language Golog provides a natural formalism for automatically composing services on the Semantic Web. To this end, we adapt and extend the Golog language to enable programs that are generic, customizable and usable in the context of the Web. Further, we propose logical criteria for these generic procedures that define when they...

  20. Reflective channel hierarchies

    Edward Curry; Desmond Chambers; Gerard Lyons
    Hierarchical channel structures are used to create granular sub-channels from a parent channel. Utilized in routing situations that are more or less static, they require that the channel namespace schema be both well defined and universally understood. The publish/subscribe messaging model currently requires a message publisher to place messages into a specific channel within the hierarchy. A relocation of responsibility for channel selection logic from the publishing client to the middleware service would open up static channel hierarchies to the application of reflective techniques. This shift in responsibilities enables the service more control over the definition, creation and maintenance of...

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