621.
Threshold Logic
- Mara J. Avedillo,Jos M. Quintana,Adoracin Rueda
sign style lies
in the intrinsic complex functions implemented by such gates, which allow system realizations
that require less threshold gates or gate levels than a design with standard logic gates. More recently,
there is an increasing interest in threshold logic because a number of theoretical results
show that polynomial size, bounded level networks of threshold gates can implement functions
that require unbounded level networks of standard logic gates. In particular, important functions
like multiple-addition, multiplication, division, or sorting can be implemented by polynomialsize
threshold circuits of small constant depth. Threshold gate networks have been found also
useful in modelling nerve nets and brain organization, and with variable...
622.
Logic in topoi: Functorial Semantics for Higher-Order Logic
Steven Awodey
The University of Chicago
Winter 1997
This dissertation investigates what may be termed the model theory of
higher-order logic using the methods of category theory. Of course, there
is no such field of logic as "higher-order model theory," and so our first concern
in chapter I will be to specify the basic objects under investigation, viz.
higher-order logical theories and their models. This is a fairly straightforward
generalization---in two different directions---of the familiar corresponding notions
for first-order logic: the notion of a logical theory is generalized from
first- to higher-order logic, and the notion of a model is generalized both
from first- to higher-order logic, and from the category...
623.
Parallel Conventional Systems versus Parallel Logic Programming Systems on Distributed Shared Memory Architectures
- Vanusa Menditi Calegario; Inès de Castro Dutra
Distributed shared memory architectures have been object of research by many computer science groups. Research goes broadly from hardware based coherence protocols to DSM software protocols on networks of workstations passing through high technology interconnection networks that reduce network latency. In this work we thoroughly investigate how different hardware cache coherence protocols affect performance of parallel logic programming systems and compare to results obtained for parallel conventional systems. We use execution-driven simulation of a hardware DSM (DASH) to investigate the access patterns and caching behaviour exhibited by parallel C programs and by Aurora, a parallel logic programming system capable of...
624.
Built-in Predicates for Extended Relational Algebra Operations in a Logic Database Language
- Yiu-kai Ng; Qing Chang
Existing rule-based nested relational database query languages do not provide built-in predicates for extended relational algebra operations. As a result, these query languages lack these traditional operators and are thus less convenient for query specifiers who recognize the expressive advantage of extended relational algebra operators. To overcome this shortcoming, we introduce a generalized Datalog language, called LDL=NR, that includes a basic set of extended relational algebra operators as builtin predicates. LDL=NR thus not only has the power to express recursive queries, but also has the expressive advantage of built-in extended relational algebra operators. Keywords: Logic programming, logic database language, nested...
625.
Using linear logic to extend the analysis capabilities of T-invariants for manufacturing applications
- F. Gasnier; M. Bourcerie; J-P. Elloy; P. Molinaro
. This paper presents a Petri net (PN) analysis technique which extend the analysis capabilities of T-invariants. This technique is based on the conversion of the PN into formulas of linear logic and on the introduction of the marking into P-invariants. It allows to test if T-invariants are pertinent related to the application's constraints of marking. Our technique determines for each valid sequence of firing of each T-invariants the initial marking needed, so results are independent of a particular initial marking. It is shown this technique is useful when timed parameters are introduced in PN using structural expansion. A particular...
626.
A.: Minimal logic programs (extended report) (2007) Technical report available at http://www.dc.fi.udc.es/~cabalar/ minlp-ext.pdf
- Pedro Cabalar; David Pearce; Agustín Valverde
Abstract. aa We consider the problem of obtaining a minimal logic program strongly equivalent (under the stable models semantics) to a given arbitrary propositional theory. We propose a method consisting in the generation of the set of prime implicates of the original theory, starting from its set of countermodels (in the logic of Here-and-There), in a similar vein to the Quine-McCluskey method for minimisation of boolean functions. As a side result, we also provide several results about fundamental rules (those that are not tautologies and do not contain redundant literals) which are combined to build the minimal programs. In particular,...
627.
Under consideration for publication in Theory and Practice of Logic Programming 1 A comparison between two logical formalisms for rewriting
- Miguel Palomino
Meseguer’s rewriting logic and the rewriting logic CRWL are two well-known approaches to rewriting as logical deduction that, despite some clear similarities, were designed with different objectives. Here we study the relationships between them, both at a syntactic and at a semantic level. Even though it is not possible to establish an entailment system map between them, both can be naturally simulated in each other. Semantically, there is no embedding between the corresponding institutions. Along the way, the notions of entailment and satisfaction in Meseguer’s rewriting logic are generalized.
628.
A Logic for Concurrent Programming
- Jayadev Misra
The UNITY-logic, a fragment of linear temporal logic, was introduced in [5]. In this paper, we
describe several recent modifications to this logic. In particular, the operator co replaces unless,
for expressing safety properties and, transient predicates form the basis for the progress properties.
Our experience suggests that these modifications simplify both the theory and practice of this logic.
Overview
The UNITY-logic, a fragment of linear temporal logic, was introduced in [5]. Experience gained in
applying this logic in practice has led us to modify some of its operators. In particular, we had adopted
unless as the primary operator for expressing safety properties, for many years. We...
629.
A Logic for Concurrent Programming
- Jayadev Misra
The UNITY-logic, a fragment of linear temporal logic, was introduced in [5]. In this paper, we
describe several recent modifications to this logic. In particular, the operator co replaces unless,
for expressing safety properties and, transient predicates form the basis for the progress properties.
Our experience suggests that these modifications simplify both the theory and practice of this logic.
Overview
The UNITY-logic, a fragment of linear temporal logic, was introduced in [5]. Experience gained in
applying this logic in practice has led us to modify some of its operators. In particular, we had adopted
unless as the primary operator for expressing safety properties, for many years. We...
630.
A Logic for Concurrent Programming
- Jayadev Misra
The UNITY-logic, a fragment of linear temporal logic, was introduced in [5]. In this paper, we
describe several recent modifications to this logic. In particular, the operator co replaces unless,
for expressing safety properties and, transient predicates form the basis for the progress properties.
Our experience suggests that these modifications simplify both the theory and practice of this logic.
Overview
The UNITY-logic, a fragment of linear temporal logic, was introduced in [5]. Experience gained in
applying this logic in practice has led us to modify some of its operators. In particular, we had adopted
unless as the primary operator for expressing safety properties, for many years. We...
631.
Exogenous Quantum Logic
- P. Mateus,A. Sernadas
when using the
new models.
Note that the endogenous approach to probabilistic logic is also useful and,
actually, widely used. By endogenous approach we mean that we tinker with the
classical models in order to make them suitable for a specific type of probabilistic
reasoning. For instance, if we want a logic for reasoning about probabilistic
transition systems (probabilistic automata) we can modify the Kripke models
of dynamic logic by labelling the transition pairs (pairs of the accessibility
relation) with probabilities [12, 15]. As another example of the endogenous
approach, consider the probabilization of first-order logic obtained by enriching
Later on, the relationship to epistemic logic was made clear in...
632.
Signed Logic Programs
- Hudson Turner
In this paper we explore the notion of a "signing" of a logic program, in the framework
of the answer set semantics. In particular, we generalize and extend the notion
of a signing, and show that even for programs with classical negation and disjunction
the existence of a signing is a simple syntactic criterion that can guarantee
several different sorts of good behavior: consistency, coincidence of consequences
under answer set and well-founded semantics, existence of "standard" answer sets
expressible in terms of the well-founded model and a signing for the program, and a
restricted monotonicity property. The key technical result in this paper is a theorem
relating the...
633.
Signed Logic Programs
- Hudson Turner
In this paper we explore the notion of a "signing" of a logic program, in the framework
of the answer set semantics. In particular, we generalize and extend the notion
of a signing, and show that even for programs with classical negation and disjunction
the existence of a signing is a simple syntactic criterion that can guarantee
several different sorts of good behavior: consistency, coincidence of consequences
under answer set and well-founded semantics, existence of "standard" answer sets
expressible in terms of the well-founded model and a signing for the program, and a
restricted monotonicity property. The key technical result in this paper is a theorem
relating the...
634.
Rational Logic Programming
- Moniz Pereira
Information about Prolog data term's dependencies on derivation goals can be used for
improved debugging, whether in the wrong solution or the missing solution type of faulty
program behaviour.
A debugger for full Prolog (itself written in Prolog) has been developed which automates
the reasoning ability required to pinpoint errors, resorting to the user only to ask
about the intended program semantics. The debugger makes cooperative use of both
the declarative and the operational semantics of Prolog programs. The approach could
be used for logic programming and theorem proving in general, and could be particularly
important when adapted to distributed systems, where it is hard to use traditional
sequential...
635.
Using Fuzzy Logic for the Specification and Retrieval of Software Components
- Ioana Şora; Doru Todinca; Universitatea Politehnica Timişoara; Departamentul De Calculatoare
Abstract: In the component based software engineering approach, a software system is viewed as an assembly of reusable independently developed components. In order to produce automated tools to support the selection and assembly of components, rigorous specifications of components and performant retrieval and selection strategies based on these specifications are needed. In this article we propose a fuzzy logic based solution for the specification and retrieval of components.
636.
Appears in Annals of Pure and Applied Logic, 107(1), pp 131--163, 2001
- Focussing And Proof; Jean-marc Andreoli
This paper proposesa synthetic presentation of the Proof Construction paradigm, which underlies most of the research and development in the so-called "logic programming" area. Two essential aspects of this paradigm are discussed here: true nondeterminism et partial information. A new formulation of Focussing, the basic property used to deal with non-determinism in proof construction, is presented. This formulation is then used to introduce a general constraint-based technique capable of dealing with partial information in proof construction.
637.
An abstract interpretation scheme for groundness, freeness, and sharing analysis of logic programs
- Renganathan Sundararajan; John S. Conery
Static global analyses based on abstract interpretation have been used to derive properties of programs. The analyses differ in the expressiveness of the abstract domains and the precision and efficiency of domain operations. We extend an abstract domain defined by Jacobs and Langen and present new abstract domain operations to derive freeness, groundness, and sharing of variables in logic programs. Analysis of non-trivial programs shows that our method is more precise and more efficient than previous proposals.
638.
Logic Programming with Ordered Disjunction
- Gerhard Brewka
Logic programs with ordered disjunction
(LPODs) combine ideas underlying Qualitative
Choice Logic [5] and answer set programming.
639.
Identifying Target Populations for Screening or Not Screening Using Logic Regression
- Janes, Holly; Pepe, Margaret S.; Kooperberg, Charles; Newcomb, Polly
Colorectal cancer remains a significant public health concern despite the fact that effective screening procedures exist and that the disease is treatable when detected at early stages. Numerous risk factors for colon cancer have been identified, but none are very predictive alone. We sought to determine whether there are certain combinations of risk factors that distinguish well between cases and controls, and that could be used to identify subjects at particularly high or low risk of the disease to target screening. Using data from the Seattle site of the Colorectal Cancer Family Registry (C-CFR), we fit logic regression models to...
640.
Concurrency and Backtracking in Vienna Parallel Logic
- eva Kühn; Herbert Pohlai; Franz Puntigam
Vienna Parallel Logic ( VPL ) is a persistent language and programming system that supports the concurrent execution of communicating processes and the computation of several alternative solutions by means of programmed backtracking. It unifies the worlds of sequential logic programming languages (Prolog) and concurrent logic programming languages (i.e., Parlog). Aspects of both language classes can be combined to any desired degree within one computation. Such a language is well suited for multidatabase applications. Further characteristics include an advanced transaction model, the support of an architecture-neutral programming style, and the treatment of failing processes. We describe the language and briefly...
