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1

Implementation of a decision support model of the supply chain management in the environment of constraint logic programming

Wikarek J.

Pomiary Automatyka Robotyka

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2013

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R. 17, nr 2

123-128

EN

The article presents the details of the implementation of the concept of a decision support model in the supply chain. To implement the model, the CLP (Constraint Logic Programming) framework called Eclipse was used. The novel way of constraints propagation is discussed, which for this class of problems improves significantly the efficiency of a search for a solution. The most important predicates implementing the model are presented and characterized. Several numerical examples are included to illustrate the implementation of the approach.

PL

W artykule przedstawiono szczegóły implementacji koncepcji modelu wspomagania decyzji w łańcuchu dostaw. Do implementacji modelu wykorzystano środowisko CLP (Programowanie w logice z ograniczeniami) o nazwie Eclipse. Omówiono nowatorski sposób propagacji ograniczeń, który dla tej klasy problemów prowadzi do znacznej poprawy wydajności znajdowania rozwiązania. W artykule przedstawiono i scharakteryzowano najważniejsze predykaty, które służą do implementacji modelu. Jako ilustracje przyjętych założeń i rozwiązań zaprezentowano przykłady liczbowe.

2

Application of constraint logic programming to decision support for the supply chain management

Sitek P.

Pomiary Automatyka Robotyka

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2013

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R. 17, nr 2

129-134

EN

Supply Chain Management (SCM) decisions can be considered at different levels of detail. At a strategic level they apply to the architecture in the supply chain, at the tactical level to transport fleet selection, selection of supply sources and distribution, and at the operational level, to the distribution of supplies and route selection. Many models of decision-making SCM have been developed. These are the linear (LP-linear programming) or mixed (MIP/MILP-Mixed Integer/Linear Integer Programming) models. These models are equipped with a smart form. Although they are well known in the OR (Operation Research) environment, they have significant drawbacks. First of all, they must support only linear constraints. For problems of larger dimensions search for solutions is long and inefficient. This paper proposes a CSP-based decision model for SCM and its implementation in the CLP (Constraint Logic Programming). In addition, it presents a novel way of constraints propagation using the structure of the problem.

PL

Decyzje w zarządzaniu łańcuchem dostaw mogą być rozpatrywane na różnych poziomach szczegółowości. Na poziomie strategicznym dotyczą samej struktury i architektury łańcucha, na poziomie taktycznym wyboru floty transportowej, a na poziomie operacyjnym wyboru tras dostaw itd. Opracowano wiele formalnych modeli zarządzania łańcuchem dostaw. Najczęściej były to modele programowania matematycznego liniowego (LP) oraz całkowitoliczbowego (MILP). Chociaż posiadały struktury dobrze rozumiane w środowiskach (OR-Badań Operacyjnych), posiadały istotne wady. Po pierwsze, mogły zawierać jedynie ograniczenia liniowe. Po drugie nie były efektywne przy większych rozmiarach problemów decyzyjnych. W Artykule zaproponowano model decyzyjny dla łańcucha dostaw oparty na problemie spełnienia ograniczeń (CSP-based) oraz jego implementacji w środowisku programowania w logice z ograniczeniami (CLP). Dodatkowo zaprezentowano nowatorski sposób propagacji ograniczeń wykorzystujący strukturę problemu.

3

Improving Reachability Analysis of Infinite State Systems by Specialization

Fioravanti F., Pettorossi A., Proietti M., Senni V.

Fundamenta Informaticae

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2012

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Vol. 119, nr 3/4

281-300

EN

We consider infinite state reactive systems specified by using linear constraints over the integers, and we address the problem of verifying safety properties of these systems by applying reachability analysis techniques. We propose a method based on program specialization, which improves the effectiveness of the backward and forward reachability analyses. For backward reachability our method consists in: (i) specializing the reactive system with respect to the initial states, and then (ii) applying to the specialized system the reachability analysis that works backwards from the unsafe states. For reasons of efficiency, during specialization we make use of a relaxation from integers to reals. In particular, we test the satisfiability or entailment of constraints over the real numbers, while preserving the reachability properties of the reactive systems when constraints are interpreted over the integers. For forward reachability our method works as for backward reachability, except that the role of the initial states and the unsafe states are interchanged. We have implemented our method using the MAP transformation system and the ALV verification system. Through various experiments performed on several infinite state systems, we have shown that our specialization-based verification technique considerably increases the number of successful verifications without a significant degradation of the time performance.

4

An Investigation of Multi-Agent Planning in CLP

Dovier A., Formisano A., Pontelli E.

Fundamenta Informaticae

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2011

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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.

5

A Folding Rule for Eliminating Existential Variables from Constraint Logic Programs

Senni V., Pettorossi A., Proietti M.

Fundamenta Informaticae

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2009

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Vol. 96, nr 3

373-393

EN

The existential variables of a clause in a constraint logic program are the variables which occur in the body of the clause and not in its head. The elimination of these variables is a transformation technique which is often used for improving program efficiency and verifying program properties. We consider a folding transformation rule which ensures the elimination of existential variables and we propose an algorithm for applying this rule in the case where the constraints are linear inequations over rational or real numbers. The algorithm combines techniques for matching terms modulo equational theories and techniques for solving systems of linear inequations. Through some examples we show that an implementation of our folding algorithm has a good performance in practice.

6

Executing suspended logic programs

Kowalski R. A., Toni F., Wetzel G.

Fundamenta Informaticae

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1998

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Vol. 34, nr 3

203-224

EN

We present an extension of Logic Programming (LP) which, in addition to ordinary LP clauses, also includes integrity constraints, explicit representation of disjunction in the bodies of clauses and in goals, and suspension of atoms as in concurrent logic languages. The resulting framework aims to unify Constraint Logic Programming (CLP), Abductive Logic Programming (ALP) and Semantic Query Optimisation (SQO) in deductive databases. We present a proof procedure for the new framework, simplifying and generalising previously proposed proof procedures for ALP. We discuss applications of the framework, formulating traditional problems from LP, ALP, CLP and SQO.