Mostrando recursos 61 - 80 de 172,139

  1. Viola: A Verifier For Interoperating Components

    Mark Grechanik
    Abstract. Two or more components (e.g., objects, modules, or programs) interoperate when they exchange data, such as XML data. Currently, there is no approach that can detect a situation at compile time when one component modifies XML data so that it becomes incompatible for use by other components, delaying discovery of errors to runtime. Our solution, a Verifier for Interoperating cOmponents for finding Logic fAults (Viola) builds abstract programs from the source code of components that exchange XML data. Viola symbolically executes these abstract programs thereby obtaining approximate specifications of the data that would be output by these components. The...

  2. THE MODAL LOGIC OF FORCING

    Joel David; Hamkins; Benedikt L Öwe
    Abstract. A set theoretical assertion ψ is forceable or possible, written ✸ ψ, if ψ holds in some forcing extension, and necessary, written ✷ ψ, if ψ holds in all forcing extensions. In this forcing interpretation of modal logic, we establish that if zfc is consistent, then the zfc-provable principles of forcing are exactly those in the modal theory S4.2. 1.

  3. DCIS 2006 A Framework for Implementing Radiation--Tolerant Circuits on Reconfigurable FPGAs

    Manuel G. Gericota; Luís F. Lemos; Gustavo R. Alves; José M. Ferreira
    Abstract — The outstanding versatility of SRAM-based FPGAs make them the preferred choice for implementing complex customizable circuits. To increase the amount of logic available, manufacturers are using nanometric technologies to boost logic density and reduce prices. However, the use of nanometric scales also makes FPGAs particularly vulnerable to radiation-induced faults, especially because of the increasing amount of configuration memory cells that are necessary to define their functionality. This paper describes a framework for implementing circuits immune to radiation-induced faults, based on a customized Triple Modular Redundancy (TMR) infrastructure and on a detection-and-fix controller. This controller is responsible for the...

  4. Automatic Synthesis of Extended Burst-Mode Circuits Using Generalized C-elements


    This paper presents a new automatic synthesis technique for extended burst-mode circuits, a class of asynchronous circuits that allow multiple-input changes between state transitions and a choice of next states based on input signal levels. The target implementation is a pseudo-static asymmetric CMOS complex gate per each output, known as generalized C-element [3, 12]. The synthesis algorithm generates hazard-free covers for set and reset functions of each output using Nowick and Dill’s exact hazard-free logic minimization algorithm [14]. Each output circuit is formed by mapping its set and reset logic to N and P stacks of an asymmetric CMOS gate...

  5. $rec.titulo


    The IST-LASAGNE project aims at designing and implementing the first, modular, scalable and truly alloptical photonic router capable of operating at 40 Gb/s. The main results achieved in the project are presented in this paper, with emphasis on the implementation of network node functionalities employing optical logic gates and optical flip-flops, as well as an economical study on the proposed all-optical node architecture. Experimental results on clock recovery, packet-rate clock recovery and 2-bit label reading are provided employing optical gates based on active Mach-Zehnder interferometers as the basic building block. The obtained results are very promising towards the goal of...

  6. ATPG for Crosstalk using Hybrid Structural SAT

    Xiaoliang Bai; Sujit Dey; Angela Krstić
    As technology evolves into the deep sub-micron era, signal integrity problems are growing into a major challenge. An important source of signal integrity problems is the crosstalk noise generated by coupling capacitances between wires. Test vectors that activate and propagate crosstalk noise effects are becoming an essential part of design verification and manufacturing test. However, deriving such vectors is a complex task. In this paper, we propose HyAC, a fast yet accurate hybrid ATPG method targeting multiple-aggressor induced crosstalk errors. Given a victim and a set of aggressors, the proposed ATPG method searches for test vectors to activate and propagate...

  7. Learning non-monotonic Logic Programs

    David Lorenzo Blanco; Dr. Alessandro Provetti
    Dissertation presented at the Facultade de Informa'tica de A Corun~a following the requirements

  8. Certifying and Synthesizing Membership Equational Proofs

    Steven Eker; Patrick Lincoln; José Meseguer
    Abstract. As the systems we have to specify and verify become larger and more complex, there is a mounting need to combine different tools and decision procedures to accomplish large proof tasks. The problem, then, is how to be sure that we can trust the correctness of a heterogeneous proof. In this work we focus on certification and synthesis of equational proofs, that are pervasive in most proof tasks and for which many tools are poorly equipped. Fortunately, equational proof engines like ELAN and Maude can perform millions of equational proof steps per second which, if certified by proof objects,...

  9. ABSTRACT: This


    article describes a formal semantics for the deontic concepts-- the concepts of permission and obligation — which arises naturally from the representations used in artificial intelligence systems Instead of treating deontic logic as a branch of modal logic, with the standard possible worlds semantics, we first develop a language for describing actions, and we define the concepts of permission and obligation in terms of these action descriptions. Using our semantic definitions, we then derive a number of intuitively plausible inferences, and we show generally that the paradoxes which are so frequently associated with deontic logic do not arise in our...

  10. M.H.Lipasti, Exploiting Partial Operand Knowledge

    Brian R. Mestan
    Conventional microprocessor designs treat register operands as atomic units. In such designs, no portion of an operand may be consumed until the entire operand has been produced. In practice, logic circuits and arithmetic units that generate some portion of an operand in advance of the remaining portions are both feasible and desirable, and have been employed in several existing designs. In this report, we propose to exploit the early partial knowledge of an instruction’s input operands for overlapping the execution of dependent instructions and resolving unknown dependences. In particular, four applications of partial operand knowledge are examined: bypassing partial operands,...

  11. Under consideration for publication in Theory and Practice of Logic Programming 1 The Deductive Database System LDL++

    Faiz Arni; Shalom Tsur; Haixun Wang; Carlo Zaniolo
    This paper describes the LDL++ system and the research advances that have enabled its design and development. We begin by discussing the new nonmonotonic and nondeterministic constructs that extend the functionality of the LDL++ language, while preserving its model-theoretic and fixpoint semantics. Then, we describe the execution model and the open architecture designed to support these new constructs and to facilitate the integration with existing DBMSs and applications. Finally, we describe the lessons learned by using LDL++ on various tested applications, such as middleware and datamining. 1

  12. Programming with Dynamic Predicate Logic


  13. Web Service Integration Based on Abstract Forms in XML for End-user Initiative Development

    Takeshi Chusho; Ryousuke Yuasa; Shinpei Nishida; Katsuya Fujiwara
    Abstract — The number of end-users using the Internet has been increasing. End-user initiative development of applications has become important for automation of end-users ’ own tasks. In particular, Web applications should be supported by domain experts themselves since Web applications must be modified frequently based on domain experts ’ ideas. This paper describes end-user initiative application forms are considered as interfaces of services based on the simple concept that “one service = one form. ” Therefore, Web service integration can be defined as form transformation from input forms into output forms. There are two problems for development of Web...

  14. Usability of State Based Boolean eBlocks

    Susan Cotterell; Frank Vahid
    The advent of sensor networks has enabled a vast number of sensor-based applications such as monitoring forest fires, ensuring structural integrity of buildings or bridges, monitoring homes or offices, and others. However, sensor network application developers are often scientists, office workers, doctors, or homeowners, and not computer programmers, often not even engineers. Thus, setting up a sensor network can be cumbersome or costly. In this paper, we discuss experiments utilizing a set of electronic blocks, called eBlocks, that developers can use to build small-scale monitor-control systems. eBlocks are intended for non-experts and do not require any programming or electronics experience....

  15. Two General Results on Intuitionistic Bounded Theories

    Fernando Ferreira
    Abstract. We study, within the framework of intuitionistic logic, two well-known general results of (classical logic) bounded arithmetic. Firstly, Parikh’s theorem on the existence of bounding terms for the provably total functions. Secondly, the result which states that adding the scheme of bounded collection to (suitable) bounded theories does not yield new Π2 consequences.

  16. TAME: A specialized specification and verification system for timed automata

    Myla Archer; Constance Heitmeyer
    Assuring the correctness of specifications of realtime systems can involve significant human effort. The use of a mechanical theorem prover to encode such specifications and to verify their properties could significantly reduce this effort. A barrier to routinely encoding and mechanically verifying specifications has been the need first to master the specification language and logic of a general theorem proving system. Our approach to overcoming this barrier is to provide mechanical support for producing specifications and verifying proofs, specialized for particular mathematical models and proof techniques. We are currently developing a mechanical verification system called TAME (Timed Automata Modeling Environment)...

  17. $rec.titulo


    Recent results in the foundations of probability theory indicate that a conditional probability can be viewed as a probability attached to a mathematical entity called a measure-free conditional. Such a measure-free conditional can receive a semantics in terms of a trivalent logic and logical operations are defined on conditionals in terms of truth-tables. It is shown that these results can be useful to justify Cox's axiomatic framework for probability as well as its application to other theories of uncertainty (Shafer's plausibility functions and Zadeh's possibility measures). Moreover it is shown that measure-free conditionals have the properties of well-behaved non-monotonic inference...

  18. Semiring-based Constraint Logic Programming: Syntax and Semantics

    Stefano Bistarelli; Ugo Montanari; Francesca Rossi
    We extend the Constraint Logic Programming (CLP) formalism in order to handle semiringbased constraint systems. This allows us to perform in the same language both constraint solving and optimization. In fact, constraint systems based on semirings are able to model both classical constraint solving and more sophisticated features like uncertainty, probability, fuzzyness, and optimization. We then provide this class of languages with three equivalent semantics: model-theoretic, fixpoint, and proof-theoretic, in the style of CLP programs. 1

  19. Fuzzy-DL Reasoning over Unknown Fuzzy Degrees

    Stasinos Konstantopoulos; Georgios Apostolikas
    In this paper we describe a fuzzy Description Logic reasoner which implements resolution in order to provide reasoning services for expressive fuzzy DLs. The main innovation of this implementation is the ability to reason over assertions with abstract (unspecified) fuzzy degrees. The answer to queries is, consequently, an algebraic expression involving the (unknown) fuzzy degrees and the degree of the query. We describe the implementation and discuss a use case in the domain of semantic meta-extraction where conventional DL reasoning is not applicable.

  20. $rec.titulo


    The goal of information extraction is to extract database records from text or semi-structured sources. Traditionally, information extraction proceeds by first segmenting each candidate record separately, and then merging records that refer to the same entities. While computationally efficient, this approach is suboptimal, because it ignores the fact that segmenting one candidate record can help to segment similar ones. For example, resolving a well-segmented field with a lessclear one can disambiguate the latter’s boundaries. In this paper we propose a joint approach to information extraction, where segmentation of all records and entity resolution are performed together in a single integrated...

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