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Model Checking in CLP
, 1999
"... We show that Constraint Logic Programming (CLP) can serve as a conceptual basis and as a practical implementation platform for the model checking of infinitestate systems. Our contributions are: (1) a semanticspreserving translation of concurrent systems into CLP programs, (2) a method for verifyi ..."
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Cited by 98 (27 self)
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We show that Constraint Logic Programming (CLP) can serve as a conceptual basis and as a practical implementation platform for the model checking of infinitestate systems. Our contributions are: (1) a semanticspreserving translation of concurrent systems into CLP programs, (2) a method for verifying safety and liveness properties on the CLP programs produced by the translation. We have implemented the method in a CLP system and verified wellknown examples of infinitestate programs over integers, using here linear constraints as opposed to Presburger arithmetic as in previous solutions.
Operational Semantics and Confluence of Constraint Propagation Rules
, 1997
"... . Constraint Handling Rules (CHR) allow one to specify and implement both propagation and simplification for userdefined constraints. Since a propagation rule is applicable again and again, we present in this paper for the first time an operational semantics for CHR that avoids the termination pro ..."
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Cited by 97 (12 self)
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. Constraint Handling Rules (CHR) allow one to specify and implement both propagation and simplification for userdefined constraints. Since a propagation rule is applicable again and again, we present in this paper for the first time an operational semantics for CHR that avoids the termination problem with propagation rules. In previous work [AFM96], a sufficient and necessary condition for the confluence of terminating simplification rules was given inspired by results about conditional term rewriting systems. Confluence ensures that the solver will always compute the same result for a given set of constraints independent of which rules are applied. The confluence of propagation rules was an open problem. This paper shows that we can also give a sufficient and a necessary condition for confluence of terminating CHR programs with propagation rules based on the more refined operational semantics. 1 Introduction Constraint Logic Programming [vH91, JM94] combines the declarativity of ...
A New Correctness Proof of the NelsonOppen Combination Procedure
 Frontiers of Combining Systems, volume 3 of Applied Logic Series
, 1996
"... The NelsonOppen combination procedure, which combines satisfiability procedures for a class of firstorder theories by propagation of equalities between variables, is one of the most general combination methods in the field of theory combination. We describe a new nondeterministic version of the p ..."
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Cited by 88 (8 self)
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The NelsonOppen combination procedure, which combines satisfiability procedures for a class of firstorder theories by propagation of equalities between variables, is one of the most general combination methods in the field of theory combination. We describe a new nondeterministic version of the procedure that has been used to extend the Constraint Logic Programming Scheme to unions of constraint theories. The correctness proof of the procedure that we give in this paper not only constitutes a novel and easier proof of Nelson and Oppen's original results, but also shows that equality sharing between the satisfiability procedures of the component theories, the main idea of the method, can be confined to a restricted set of variables.
Design and semantics of a decentralized authorization language
 20TH IEEE COMPUTER SECURITY FOUNDATIONS SYMPOSIUM
, 2007
"... We present a declarative authorization language that strikes a careful balance between syntactic and semantic simplicity, policy expressiveness, and execution efficiency. The syntax is close to natural language, and the semantics consists of just three deduction rules. The language can express many ..."
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Cited by 73 (11 self)
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We present a declarative authorization language that strikes a careful balance between syntactic and semantic simplicity, policy expressiveness, and execution efficiency. The syntax is close to natural language, and the semantics consists of just three deduction rules. The language can express many common policy idioms using constraints, controlled delegation, recursive predicates, and negated queries. We describe an execution strategy based on translation to Datalog with Constraints, and tablebased resolution. We show that this execution strategy is sound, complete, and always terminates, despite recursion and negation, as long as simple syntactic conditions are met.
Extracting Buildings from Aerial Images using Hierarchical Aggregation in 2D and 3D
, 1998
"... We propose a modelbased approach to automated 3D extraction of buildings from aerial images. We focus on a reconstruction strategy that is not restricted to a small class of buildings. Therefore, we employ a generic modeling approach which relies on the well dened combination of building part mo ..."
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Cited by 73 (4 self)
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We propose a modelbased approach to automated 3D extraction of buildings from aerial images. We focus on a reconstruction strategy that is not restricted to a small class of buildings. Therefore, we employ a generic modeling approach which relies on the well dened combination of building part models. Building parts are classied by their roof type.
Logic program specialisation through partial deduction: Control issues
 THEORY AND PRACTICE OF LOGIC PROGRAMMING
, 2002
"... Program specialisation aims at improving the overall performance of programs by performing source to source transformations. A common approach within functional and logic programming, known respectively as partial evaluation and partial deduction, is to exploit partial knowledge about the input. It ..."
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Cited by 65 (13 self)
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Program specialisation aims at improving the overall performance of programs by performing source to source transformations. A common approach within functional and logic programming, known respectively as partial evaluation and partial deduction, is to exploit partial knowledge about the input. It is achieved through a wellautomated application of parts of the BurstallDarlington unfold/fold transformation framework. The main challenge in developing systems is to design automatic control that ensures correctness, efficiency, and termination. This survey and tutorial presents the main developments in controlling partial deduction over the past 10 years and analyses their respective merits and shortcomings. It ends with an assessment of current achievements and sketches some remaining research challenges.
Homeomorphic Embedding for Online Termination
 STATIC ANALYSIS. PROCEEDINGS OF SAS’98, LNCS 1503
, 1998
"... Recently wellquasi orders in general, and homeomorphic embedding in particular, have gained popularity to ensure the termination of program analysis, specialisation and transformation techniques. In this paper, ..."
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Cited by 63 (9 self)
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Recently wellquasi orders in general, and homeomorphic embedding in particular, have gained popularity to ensure the termination of program analysis, specialisation and transformation techniques. In this paper,
The KGP Model of Agency
 In Proc. ECAI2004
, 2004
"... This paper presents a new model of agency, called the KGP (Knowledge, Goals and Plan) model. This draws from the classic BDI model and proposes a hierarchical agent architecture with a highly modular structure that synthesises various reasoning and sensing capabilities of the agent in an open and dy ..."
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Cited by 63 (41 self)
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This paper presents a new model of agency, called the KGP (Knowledge, Goals and Plan) model. This draws from the classic BDI model and proposes a hierarchical agent architecture with a highly modular structure that synthesises various reasoning and sensing capabilities of the agent in an open and dynamic environment. The novel features of the model include: its innovative use of Computational Logic (CL) in a way that facilitates both the formal analysis of the model and its computational realisability directly from the highlevel specification of the agents (a first prototype for the development of KGP agents exists, based upon a correct computational counterpart of the model), the modular separation of concerns and flexibility afforded by the model in designing heterogeneous agents and in developing independently the various components of an agent, and the declarative agent control provided through a contextsensitive cycle CL theory component that regulates the agent's operational behaviour, according to the current circumstances of operation, thus breaking away from the conventional onesizefitsall control of operation.
A Foundation for Higherorder Concurrent Constraint Programming
, 1994
"... We present the flcalculus, a computational calculus for higherorder concurrent programming. The calculus can elegantly express higherorder functions (both eager and lazy) and concurrent objects with encapsulated state and multiple inheritance. The primitives of the flcalculus are logic variables ..."
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Cited by 63 (13 self)
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We present the flcalculus, a computational calculus for higherorder concurrent programming. The calculus can elegantly express higherorder functions (both eager and lazy) and concurrent objects with encapsulated state and multiple inheritance. The primitives of the flcalculus are logic variables, names, procedural abstraction, and cells. Cells provide a notion of state that is fully compatible with concurrency and constraints. Although it does not have a dedicated communication primitive, the flcalculus can elegantly express onetomany and manytoone communication. There is an interesting relationship between the flcalculus and the ßcalculus: The flcalculus is subsumed by a calculus obtained by extending the asynchronous and polyadic ßcalculus with logic variables. The flcalculus can be extended with primitives providing for constraintbased problem solving in the style of logic programming. A such extended flcalculus has the remarkable property that it combines firstor...