Results 21  30
of
226
The Logic of Authentication Protocols
 Foundations of Security Analysis and Design, LNCS 2171
, 2001
"... This paper is based on a course Syverson taught at the 1st International School on Foundations of Security Analysis and Design (FOSAD'00) in Bertinoro, Italy in September 2000. Cervesato was a student there. The work of the first author was supported by ONR. The work of the second author was support ..."
Abstract

Cited by 29 (0 self)
 Add to MetaCart
This paper is based on a course Syverson taught at the 1st International School on Foundations of Security Analysis and Design (FOSAD'00) in Bertinoro, Italy in September 2000. Cervesato was a student there. The work of the first author was supported by ONR. The work of the second author was supported by NSF grant INT9815731 "Logical Methods for Formal Verification of Software" and by NRL under contract N0017300C2086
A Logical Analysis of Aliasing in Imperative HigherOrder Functions
 INTERNATIONAL CONFERENCE ON FUNCTIONAL PROGRAMMING, ICFP’05
, 2005
"... We present a compositional program logic for callbyvalue imperative higherorder functions with general forms of aliasing, which can arise from the use of reference names as function parameters, return values, content of references and part of data structures. The program logic ..."
Abstract

Cited by 28 (3 self)
 Add to MetaCart
We present a compositional program logic for callbyvalue imperative higherorder functions with general forms of aliasing, which can arise from the use of reference names as function parameters, return values, content of references and part of data structures. The program logic
Specifying Closed World Assumptions for Logic Databases
 2nd Symp. on Mathematical Fundamentals of Database Syst. (MFDBS'89), 6884, LNCS 364
, 1989
"... "Closed world assumptions" (CWAs) are an important class of implicit completions for logic databases. We present a new general definition of CWA; it is parameterized, so that known and new versions of CWAs can be derived as special cases. Our CWA, in turn, instantiates the more basic notion of "data ..."
Abstract

Cited by 24 (21 self)
 Add to MetaCart
"Closed world assumptions" (CWAs) are an important class of implicit completions for logic databases. We present a new general definition of CWA; it is parameterized, so that known and new versions of CWAs can be derived as special cases. Our CWA, in turn, instantiates the more basic notion of "database completion" and satisfies natural properties. It can even be characterized by the property of determining maximal completions without generating too much new information. We study syntactic as well as semantic definitions and prove them to be equivalent. By discussing several instances of CWAs we demonstrate the applicability of our framework to database specification. 1 Introduction A logic database stores formulae which describe facts corresponding to conventional database information, rules for deducing further information, and indefinite information. Thus, a database state is a set of formulae and answers to queries should be logical consequences of such a state. The formulae are u...
Design and Implementation of ROCK & ROLL: A Deductive ObjectOriented Database System
 Information Systems
, 1995
"... This paper presents an approach to the development of a deductive objectoriented database system, describing the key design decisions and their consequences for implementation. The approach is novel, in that it integrates an objectoriented database system manipulated using an imperative programmin ..."
Abstract

Cited by 24 (4 self)
 Add to MetaCart
This paper presents an approach to the development of a deductive objectoriented database system, describing the key design decisions and their consequences for implementation. The approach is novel, in that it integrates an objectoriented database system manipulated using an imperative programming language (ROCK) with a logic language for expressing queries and methods (ROLL). The integration is made seamless by deriving both the imperative and logic languages from a single formally defined data model, thereby avoiding impedance mismatches when they are integrated. Key words: Deductive ObjectOriented Databases, Deductive Databases, ObjectOriented Databases, Database Programming, Logic Programming. 1. INTRODUCTION The two most prominent of the emerging approaches to database programming build upon the deductive and the objectoriented paradigms. Both of these approaches have significant strengths. Deductive databases (DDBs) have a formal basis in first order logic, support expressi...
Reducing the Search Space for Conceptual Schema Transformation
 Data & Knowledge Engineering
, 1993
"... In this paper we focus on the transformation of a conceptual schema into an internal schema. For a given conceptual schema, quite a number of internal schemata can be derived. This number can be reduced by imposing restrictions on internal schemata. We present a transformation algorithm that can gen ..."
Abstract

Cited by 22 (11 self)
 Add to MetaCart
In this paper we focus on the transformation of a conceptual schema into an internal schema. For a given conceptual schema, quite a number of internal schemata can be derived. This number can be reduced by imposing restrictions on internal schemata. We present a transformation algorithm that can generate internal schemata of several types (including the relational model and the NF 2 model). Guidance parameters are used to impose further restrictions. We harmonise the different types of schemata by extending the conceptual language, such that both the conceptual and the internal models can be represented within the same language. Keywords: Conceptual schema, internal schema, schema transformation, relational data model, NF 2 data model. 1 Introduction The importance of conceptual modelling has been generally recognised. The advantage is that it gives the designer the opportunity to separate the concern of constructing a correct model from that of finding an efficient implementation...
An Effective Deductive ObjectOriented Database Through Language Integration
 Proc. 20th Int. Conf. on Very Large Data Bases (VLDB
, 1994
"... This paper presents an approach to the development of a practical deductive objectoriented database (DOOD) system baaed upon the integration of a logic query language with an imperative programming language in the context of an objectoriented data model. The approach is novel, in that a formally ..."
Abstract

Cited by 22 (9 self)
 Add to MetaCart
This paper presents an approach to the development of a practical deductive objectoriented database (DOOD) system baaed upon the integration of a logic query language with an imperative programming language in the context of an objectoriented data model. The approach is novel, in that a formally defined data model has been used as the starting point for the development of the two languages. This has enabled a seamless integration of the two languages, which is the central theme of this paper. It is shown how the two languages have been developed from the underlying data model, and several alterna, tive approaches to their integration are presented, one of which has been chosen for implementation. The approach is compared with other examples of language integration in a database context, and it is argued that the resulting system overcomes a number of important challenges associated with the development of practical deductive objectoriented database systems. Permission to copy without fee all of part of thi6 maten’al i6 granted provided that the copier are not made or dlttibarted for direct commercial advantage, the VLDB copqright notice and the title of the publication and it6 date appear, and notice is
A MultiContext Monotonic Axiomatization of Inessential NonMonotonicity
 DIST, University of Genova, Italy
, 1988
"... The main premise of this paper is that certain kinds of nonmonotonic reasoning can be solved within first order logic in a simple monotonic way by formulating problems in a suitable environment. Any problem is formalized as a set of contexts, where a context is a (first order) formalization of a ..."
Abstract

Cited by 22 (10 self)
 Add to MetaCart
The main premise of this paper is that certain kinds of nonmonotonic reasoning can be solved within first order logic in a simple monotonic way by formulating problems in a suitable environment. Any problem is formalized as a set of contexts, where a context is a (first order) formalization of a piece of the problem. Reasoning comes out as a result of deduction in different contexts. The claim is that proofs built in this way are clearer and better resemble the kind of explanation that humans give when describing some phenomenon. This thesis is articulated discussing the example about nonmonotonic reasoning reported in [MD80].
Uniquest: Determining the Semantics of Complex Uniqueness Constraints
 The Computer Journal
, 1993
"... In this article the Uniquest Algorithm (the "quest for uniqueness"), defined in the Predicator Model, is discussed in depth. The Predicator Model is a general platform for objectrole models. The Uniquest Algorithm is a constructive formal definition of the semantics of uniqueness constraints. As s ..."
Abstract

Cited by 21 (14 self)
 Add to MetaCart
In this article the Uniquest Algorithm (the "quest for uniqueness"), defined in the Predicator Model, is discussed in depth. The Predicator Model is a general platform for objectrole models. The Uniquest Algorithm is a constructive formal definition of the semantics of uniqueness constraints. As such, it facilitates the implementation in socalled CASEtools. The Uniquest Algorithm provides a systematic approach for the interpretation of complex uniqueness constraints. This interpretation process is easily traced, using an extra formalism, called the Object Relation Network (ORN). The ORN is a directed graph with labelled edges, representing an objectrole information structure. Intermediate results that are outside the scope of the information structure at hand, are represented elegantly as an ORN. A number of theoretical and practical examples prove the power of the Uniquest Algorithm. In these examples we will encouter complex uniqueness constraints, that are missed easily. The Un...
Hypercomputation and the Physical ChurchTuring Thesis
, 2003
"... A version of the ChurchTuring Thesis states that every e#ectively realizable physical system can be defined by Turing Machines (`Thesis P'); in this formulation the Thesis appears an empirical, more than a logicomathematical, proposition. We review the main approaches to computation beyond Turing ..."
Abstract

Cited by 21 (0 self)
 Add to MetaCart
A version of the ChurchTuring Thesis states that every e#ectively realizable physical system can be defined by Turing Machines (`Thesis P'); in this formulation the Thesis appears an empirical, more than a logicomathematical, proposition. We review the main approaches to computation beyond Turing definability (`hypercomputation'): supertask, nonwellfounded, analog, quantum, and retrocausal computation. These models depend on infinite computation, explicitly or implicitly, and appear physically implausible; moreover, even if infinite computation were realizable, the Halting Problem would not be a#ected. Therefore, Thesis P is not essentially di#erent from the standard ChurchTuring Thesis.
MEBN: A Logic for OpenWorld Probabilistic Reasoning
 Research Paper
, 2004
"... Uncertainty is a fundamental and irreducible aspect of our knowledge about the world. Probability is the most wellunderstood and widely applied logic for computational scientific reasoning under uncertainty. As theory and practice advance, generalpurpose languages are beginning to emerge for which ..."
Abstract

Cited by 20 (8 self)
 Add to MetaCart
Uncertainty is a fundamental and irreducible aspect of our knowledge about the world. Probability is the most wellunderstood and widely applied logic for computational scientific reasoning under uncertainty. As theory and practice advance, generalpurpose languages are beginning to emerge for which the fundamental logical basis is probability. However, such languages have lacked a logical foundation that fully integrates classical firstorder logic with probability theory. This paper presents such an integrated logical foundation. A formal specification is presented for multientity Bayesian networks (MEBN), a knowledge representation language based on directed graphical probability models. A proof is given that a probability distribution over interpretations of any consistent, finitely axiomatizable firstorder theory can be defined using MEBN. A semantics based on random variables provides a logically coherent foundation for open world reasoning and a means of analyzing tradeoffs between accuracy and computation cost. Furthermore, the underlying Bayesian logic is inherently open, having the ability to absorb new facts about the world, incorporate them into existing theories, and/or modify theories in the light of evidence. Bayesian inference provides both a proof theory for combining prior knowledge with observations, and a learning theory for refining a representation as evidence accrues. The results of this paper provide a logical foundation for the rapidly evolving literature on firstorder Bayesian knowledge representation, and point the way toward Bayesian languages suitable for generalpurpose knowledge representation and computing. Because firstorder Bayesian logic contains classical firstorder logic as a deterministic subset, it is a natural candidate as a universal representation for integrating domain ontologies expressed in languages based on classical firstorder logic or subsets thereof.