Wyniki wyszukiwania - BazTech

1

Extending Logic Programming with Labelled Variables : Model and Semantics

Calegari R., Denti E., Dovier A., Omicini A.

Fundamenta Informaticae

|

2018

|

Vol. 161, nr 1/2

53--74

EN

In order to enable logic programming to deal with the diversity of pervasive systems, where many heterogeneous, domain-specific computational models could benefit from the power of symbolic computation, we explore the expressive power of labelled systems. To this end, we define a new notion of truth for logic programs extended with labelled variables interpreted in non-Herbrand domains-where, however, terms maintain their usual Herbrand interpretations. First, a model for labelled variables in logic programming is defined. Then, the fixpoint and the operational semantics are presented and their equivalence is formally proved. A meta-interpreter implementing the operational semantics is also introduced, followed by some case studies aimed at showing the effectiveness of our approach in selected scenarios.

2

A Theoretical Perspective of Coinductive Logic Programming

Ancona D., Dovier A.

Fundamenta Informaticae

|

2015

|

Vol. 140, nr 3/4

221--246

EN

In this paper we study the semantics of Coinductive Logic Programming and clarify its intrinsic computational limits, which prevent, in particular, the definition of a complete, computable, operational semantics. We propose a new operational semantics that allows a simple correctness result and the definition of a simple meta-interpreter. We compare, and prove the equivalence, with the operational semantics defined and used in other papers on this topic.

3

A Tabled Prolog Program for Solving Sokoban

Zhou N.-F., Dovier A.

Fundamenta Informaticae

|

2013

|

Vol. 124, nr 4

561--575

EN

This paper presents our program in B-Prolog submitted to the third ASP solver competition for the Sokoban problem. This program, based on dynamic programming, treats Sokoban as a generalized shortest path problem. It divides a problem into independent subproblems and uses mode-directed tabling to store subproblems and their answers. This program is very simple but quite efficient. Without use of any sophisticated domain knowledge, it easily solves 14 of the 15 instances used in the competition. We show that the approach can be easily applied to other optimization planning problems.

4

Morphos Configuration Engine: the Core of a Commercial Configuration System in CLP(FD)

Campagna D., De Rosa C., Dovier A., Montanari A., Piazza C.

Fundamenta Informaticae

|

2011

|

Vol. 105, nr 1/2

105-133

EN

Product configuration systems are an emerging software technology that supports companies in deploying mass customization strategies. In this paper, we describe a CLP-based reasoning engine that we developed for a commercial configuration system. We first illustrate the advantages of the CLP approach to product configuration over other ones. Then, we describe the actual encoding of the considered product configuration problem as a constraint satisfaction problem. We devote a special attention to the key issues of constraint propagation and optimization as well as to the relevant process of assignment revision. A comparison with existing systems for product configuration concludes the paper.

5

An Investigation of Multi-Agent Planning in CLP

Dovier A., Formisano A., Pontelli E.

Fundamenta Informaticae

|

2011

|

Vol. 105, nr 1/2

79-103

EN

This paper explores the use of Constraint Logic Programming (CLP) as a platform for experimenting with planning problems in the presence of multiple interacting agents. The paper develops a novel constraint-based action language, BMAP, that enables the declarative description of large classes of multi-agent and multi-valued domains. BMAP supports several complex features, including combined effects of concurrent and interacting actions, concurrency control, and delayed effects. The paper presents a mapping of BMAP theories to CLP and it demonstrates the effectiveness of an implementation in SICStus Prolog on several benchmark problems. The effort is an evolution of previous research on using CLP for single-agent domains, demonstrating the flexibility of CLP technology to handle the more complex issues of multi-agency and concurrency.

6

GASP: Answer Set Programming with Lazy Grounding

Dal Palu A., Dovier A., Pontelli E., Rossi G.

Fundamenta Informaticae

|

2009

|

Vol. 96, nr 3

297-322

EN

In recent years, Answer Set Programming has gained popularity as a viable paradigm for applications in knowledge representation and reasoning. This paper presents a novel methodology to compute answer sets of an answer set program. The proposed methodology maintains a bottom-up approach to the computation of answer sets (as in existing systems), but it makes use of a novel structuring of the computation, that originates from the non-ground version of the program. Grounding is lazily performed during the computation of the answer sets. The implementation has been realized using Constraint Logic Programming over finite domains.

7

A uniform axiomatic view of lists, multisets, and sets, and the relevant unification algorithms

Dovier A., Policriti A., Rossi G.

Fundamenta Informaticae

|

1998

|

Vol. 36, nr 2,3

201-234

EN

The first-order theories of lists, multisets, compact lists (i.e., lists, where the number of contiguous occurrences of each element is immaterial) , and sets are introduced via axioms. Such axiomatizations are shown to be very well-suited for the integration with free functor symbols governed by the classical Clark's axioms in the context of (Constraint) Logic Programming. Adaptations of the extensionally principle to the various theories taken into account is then exploited in the design of unification algorithms for the considered data structures. All the theories presented can be combined providing frameworks to deal with several of the proposed data structures simultaneously. The unification algorithms proposed can be combined (merged) as well, to produce engines for such combination theories.