Mostrando recursos 110,721 - 110,740 de 188,269

  1. Design of CMOS Dynamic Circuits with . . .

    Fernando Mendoza-Hernandez; O Mendoza-hernández; Monico Linares; Mónico Linares; Victor H. Champac; Víctor H. Champac
    this paper we present a new noise-tolerant dynamic circuit technique suitable for pipelined dynamic digital circuits. The effectiveness of this technique is demonstrated by means of HSPICE simulations for two kind of gates, CMOS AND and OR gates, both TSPC and Domino. In order to have a clear idea about this proposal's noise immunity improvement we compare its performance with previous works. Simulation results show that the proposed technique has an improvement in the noise tolerance and the 9999 quotient over the conventional dynamic logic and the previous noise-tolerant dynamic circuit techniques with a slight delay and power increase

  2. Towards an Axiomatic Theory of Consciousness

    Jim Cunningham
    In this paper we seek to provide elements of an axiomatic theory for a sentient consciousness as a quanti ed form of introspective awareness. A crucial step for its formulation is use of an interval temporal logic to give expression to on-going conditions such as those represented by the progressive aspect in natural language. In this way we are able to enrich more stative mental models so that an agent's internal activities and its perception of external processes can be represented more faithfully. The need for agent consciousness research is briey discussed.

  3. Hardware/Software Design Space Exploration for a Reconfigurable Processor

    Alberto La Rosa; Alberto La; Rosa Luciano; Lavagno Claudio Passerone
    This paper describes an approach to hardware /software design space exploration for reconfigurable processors. The existing compiler tool-chain, because of the user-definable instructions, needs to be extended in order to offer developers an easy way to explore design space. Such extension often is not easy to use for developer that have only a software background, thus ignoring reconfigurable architecture details or hardware logic synthesis on FPGA. Our approach differs from others because it is based on a simple extension on the standard programming model well known to software developers.

  4. SIGMAR: A Fuzzy Expert System for Critiquing Marine Forecasts Bjarne Hansen Maritimes Weather Centre Environment Canada 1496 Bedford Highway Bedford, Nova Scotia Canada B4A 1E5

    Bjarne Hansen Ec; Bjarne Hansen; Maritimes Weather Centre
    Meteorological information and knowledge are often uncertain, ambiguous, or vaguely defined. Fuzzy logic lets expert systems perform optimally with uncertain or ambiguous data and knowledge. With a fuzzy logic framework, one can efficiently implement linguistically expressed rules derived from experts. Operational meteorology is therefore treated as a fuzzy environment. An argument is made for the applicability of methods based on fuzzy logic for the optimal solution of problems related to the evaluation of meteorological data and forecasts. An expert system, SIGMAR, has been designed which uses fuzzy methods to interpret meteorological data. The system automatically evaluates the significance of actual...

  5. Is the Brain a Digital Computer?

    John Searle; I. Introduction; Strong Ai; Weak Ai
    This paper is about Cognitivism, and I had better say at the beginning what motivates it. If you read books about the brain (say Shepherd (1983) or Kuffler and Nicholls (1976)) you get a certain picture of what is going on in the brain. If you then turn to books about computation (say Boolos and Jeffrey, 1989) you get a picture of the logical structure of the theory of computation. If you then turn to books about cognitive science, (say Pylyshyn, 1985) they tell you that what the brain books describe is really the same as what the computability books...

  6. Surfing: A Robust Form of Wave Pipelining Using Self-Timed Circuit Techniques

    Brian D. Winters; Mark R. Greenstreet
    This paper presents "surfing," a novel variation of wave pipelining. In previous wave pipelined designs, timing uncertainty grows monotonically as data propagates through gates and other logic elements. Our designs propagate a timing pulse along with the data values, and our logic elements have delays that decrease in the presence of the pulse. This produces a "surfing" effect wherein events are bound in close proximity to the timing pulse. This produces a robust variant of wave-pipelining where timing dispersion is bounded regardless of the length of the pipeline. We demonstrate our approach with the design of a simple proof-of-concept chip.

  7. A Polynomial Translation of Logic Programs with Nested Expressions into Disjunctive Logic Programs: Preliminary Report

    David Pearce; Vladimir Sarsakov; Torsten Schaub; Hans Tompits; Stefan Woltran
    Nested logic programs have recently been introduced in order to allow for arbitrarily nested formulas in the heads and the bodies of logic program rules under the answer sets semantics. Previous results show that nested logic programs can be transformed into standard (unnested) disjunctive logic programs in an elementary way, applying the negation-as-failure operator to body literals only. This is of great practical relevance since it allows us to evaluate nested logic programs by means of off-the-shelf disjunctive logic programming systems, like DLV. However, it turns out that this straightforward transformation results in an exponential blow-up in the worst-case, despite...

  8. Methods for accurate retrieval of MEDLINE citations

    In Functional Genomics
    The lack of discipline and consistency in gene naming poses a formidable challenge to researchers in locating relevant information sources in the genomics literature. The research presented here primarily focuses on how to find the MEDLINE citations that describe functions of particular genes. We developed new methods and extended current techniques that may help researchers to retrieve such citations accurately. We further evaluated several machine learning and optimization algorithms to identify the sentences describing gene functions in given citations. Keywords: Genomics; MEDLINE; MeSH; Information Retrieval; Propositional Logic; Decision Lists; Machine Learning; Bayesian Networks; Model Averaging; Probabilistic Inference.

  9. Logic-Based Integration of Query Answering and Knowledge Discovery

    Marcelo A. T. Aragao; Alvaro A. A. Fernandes
    There is currently great interest in integrating knowledge discovery research into mainstream database systems. Such an enterprise is nontrivial because knowledge discovery and database systems are rooted in di#erent paradigms, therefore foundational work needs to be carried out and a candidate unified syntax and semantics needs to be proposed.

  10. The Use of DL in Component Libraries - First Experiences

    Ragnhild Van Der Straeten; Ragnhild Van; Der Straeten; Miro Casanova
    Component-based software development (CBSD) is a very promising software engineering technique for improving reuse and maintenance of software components. However, in order to be able to reuse the components, developers should be aware of the available components in the company, in which contexts those components can be used and how they will behave. Our approach is to use the technique of software libraries to classify the components. The structure of these libraries is speci ed by ontologies. Those ontologies are speci ed in the SHIQ description logic.

  11. Exploiting Positive Equality in a Logic of Equality with Uninterpreted Functions

    Randal E. Bryant; Steven German; Miroslav N. Velev
    . In using the logic of equality with unininterpreted functions to verify hardware systems, specific characteristics of the formula describing the correctness condition can be exploited when deciding its validity. We distinguish a class of terms we call "p-terms" for which equality comparisons can appear only in monotonically positive formulas. By applying suitable abstractions to the hardware model, we can express the functionality of data values and instruction addresses flowing through an instruction pipeline with p-terms. A decision procedure can exploit the restricted uses of p-terms by considering only "maximally diverse" interpretations of the associated function symbols, where every function...

  12. Computing Answer Sets of a Logic Program

    Via-Enumeration Of Sat; Yuliya Lierler; Marco Maratea
    Answer set programming is a new programming paradigm proposed in [1] and [2], and based on the answer set semantics of Prolog [3]. It is well known that an answer set for a logic program is also a model of the program's completion [4]. The converse is true when the logic program is "tight" [6, 5]. Lin and Zhao [7] showed that for non-tight programs the models of completion which do not correspond to answer sets can be eliminated by adding to the completion what they called "loop formulas". Nevertheless, their solver ASSAT has some disadvantages: it can work only...

  13. Software Decelerators

    Eric Keller Gordon; Gordon Brebner; Phil James-roxby
    This paper introduces the notion of a software decelerator, to be used in logic-centric system architectures. Functions are offloaded from logic to a processor, accepting a speed penalty in order to derive overall system benefits in terms of improved resource use (e.g. reduced area or lower power consumption) and/or a more efficient design process. The background rationale for such a strategy is the increasing availability of embedded processors `for free' in Platform FPGAs. A detailed case study of the concept is presented, involving the provision of a high-level technology-independent design methodology based upon a finite state machine model. This illustrates...

  14. Confirmation-Guided Discovery of First-Order Rules with Tertius

    Rules Withtertius; Peter A. Flach; Nicolas Lachiche
    This paper deals with learning first-order logic rules from data lacking an explicit classification predicate. Consequently, the learned rules are not restricted to predicate definitions as in supervised inductive logic programming. First-order logic offers the ability to deal with structured, multi-relational knowledge. Possible applications include first-order knowledge discovery, induction of integrity constraints in databases, multiple predicate learning, and learning mixed theories of predicate definitions and integrity constraints. One of the contributions of our work is a heuristic measure of confirmation, trading off novelty and satisfaction of the rule. The approach has been implemented in the Tertius system. The system performs...

  15. Mechanised Reasoning and Model Generation for Extended Modal Logics

    Renate A. Schmidt; Ullrich Hustadt
    The approach presented in this overview paper exploits that modal logics can be seen to be fragments of first-order logic and deductive methods can be developed and studied within the framework of firstorder resolution. We focus on a class of extended modal logics very similar in spirit to propositional dynamic logic and closely related to description logics. We review and discuss the development of decision procedures for decidable extended modal logics and look at methods for automatically generating models.

  16. A Multimodal Logic Approach to Order of

    Magnitude Qualitative Reasoning; Alfredo Burrieza; Manuel Ojeda-aciego
    In this work we develop a logic for formalizing qualitative reasoning.

  17. Lecture Notes: “Land Evaluation” by

    David G. Rossiter
    Contents for Part 5 : "Uncertainty" 1. Uncertainty .................................................................... 2 1.1 Data uncertainty: measurement and sampling errors .2 1.2 Representing the data values of a map unit................3 1.3 Data uncertainty: correlated variables........................5 1.4 Rule uncertainty ........................................................5 1.5 Error propagation ......................................................6 1.6 Monte Carlo simulation............................................12 2. Fuzzy logic & continuous classification ..........................15 2.1 Why use continuous classification in land evaluation?15 2.2 A fuzzy set and its membership function..................15 2.3 Computing with fuzzy sets.......................................17 3. Spatial variability ..........................................................18 3.1 Why natural resources vary in space ........................18 3.2 Key point: spatial dependence ..

  18. AND/OR Trees for the Synthesis of Functional

    Logic Programs Ferri-Ram; J. Hern; Ez-orallo M. J. Ramrez-quintana
    In this paper, we present the implementation of a method for generating very expressive decision trees over a functional logic language. The method is based on several partitions which allow us the induction of nested and recursive functions and the use of background knowledge. The construction of the decision tree is guided according to the MDL principle. Hence, the search space is covered in a short-to-long fashion. Moreover, a multiple decision tree is obtained rather than a single tree. We show that the method is suitable for classi cation problems.

  19. On the Indiscernibility of Individuals in Logic Programming

    Thomas Eiter; Thomas Eiter; Georg Gottlob; Georg Gottlob; Nicola Leone; Nicola Leone
    According to Leibniz's principle, two individuals a and b are indiscernible, if they share the same properties. Indiscernibility of objects provides a potential for optimization in deductive systems, and has e.g. been exploited in the area of active database systems. In this paper, we address the issue of indiscernibility in logic programs and outline possible benefits for computation. After a formal definition of the notion of indiscernibility, we investigate some basic properties. The main contribution is then an analysis of the computational cost of checking indiscernibility of individuals (i.e. constants) in logic programs without function symbols, which we pursue in...

  20. Formulas for which Contraction is

    Admissible Arnon Avron
    A formula A is said to have the contraction property in a logic L i# whenever A, A, # B (when # is a multiset) also A, # B. In MLL and in MALL without the additive constants a formula has the contraction property i# it is a theorem. Adding the mix rule does not change this fact. In MALL (with or without mix) and in a#ne logic A has the contraction property i# either A is provable or A is equivalent to the additive constant 0. We present some general proof-theoretical principles from which all these results (and others)...

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