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31
A Field Programmable Gate Array Based FiniteDomain Constraint Solver
, 2008
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Constraint Propagation on Multiple Domains
 Universidad Politecnica de Valencia
, 2000
"... In previous work we have presented a simple generic framework to solve constraints on any domain (finite or infinite) which has a lattice structure. The approach is based on the use of a single constraint similar to the indexicals used by constraint logic programming (CLP) over finite domains an ..."
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In previous work we have presented a simple generic framework to solve constraints on any domain (finite or infinite) which has a lattice structure. The approach is based on the use of a single constraint similar to the indexicals used by constraint logic programming (CLP) over finite domains and on a particular definition of an interval lattice built from any computation domain.
An Experimental Comparison of Constraint Logic Programming and Answer Set Programming
"... Answer Set Programming (ASP) and Constraint Logic Programming over finite domains (CLP(FD)) are two declarative programming paradigms that have been extensively used to encode applications involving search, optimization, and reasoning (e.g., commonsense reasoning and planning). This paper presents e ..."
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Answer Set Programming (ASP) and Constraint Logic Programming over finite domains (CLP(FD)) are two declarative programming paradigms that have been extensively used to encode applications involving search, optimization, and reasoning (e.g., commonsense reasoning and planning). This paper presents experimental comparisons between the declarative encodings of various computationally hard problems in both frameworks. The objective is to investigate how the solvers in the two domains respond to different problems, highlighting strengths and weaknesses of their implementations, and suggesting criteria for choosing one approach over the other. Ultimately, the work in this paper is expected to lay the foundations for transfer of technology between the two domains, e.g., suggesting ways to use CLP(FD) in the execution of ASP. 1
Inference fusion: a hybrid approach to taxonomic reasoning with numeric constraints
"... We present a hybrid way to extend taxonomic reasoning using inference fusion, i.e. the dynamic combination of inferences from distributed heterogeneous reasoners. Our approach integrates results from a DLbased taxonomic reasoner with results from a constraint solver. Inference fusion is carried out ..."
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We present a hybrid way to extend taxonomic reasoning using inference fusion, i.e. the dynamic combination of inferences from distributed heterogeneous reasoners. Our approach integrates results from a DLbased taxonomic reasoner with results from a constraint solver. Inference fusion is carried out by (i) parsing heterogeneous input knowledge, producing suitable homogeneous subset of the input knowledge for each specialised reasoner; (ii) processing the homogeneous knowledge, collecting the reasoning results and passing them to the other reasoner if appropriate; (iii) combining the results of the two reasoners. We discuss the benefits of our approach to the ontological reasoning and demonstrate our ideas by proposing a hybrid modelling languages, DL(D)/S, and illustrating its use by means of examples.
Evaluating asp and commercial solvers on the CSPLib (preliminary work
 In WLP
, 2006
"... 1 Introduction The last decade has witnessed a large effort in the development of solvers for combinatorial problems. The traditional approach based on writing ad hoc algorithms and programs (complete, such as backtracking, or incomplete, such as tabu search, simulated annealing, etc.) or translati ..."
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1 Introduction The last decade has witnessed a large effort in the development of solvers for combinatorial problems. The traditional approach based on writing ad hoc algorithms and programs (complete, such as backtracking, or incomplete, such as tabu search, simulated annealing, etc.) or translating ina format suitable for Integer Programming solvers (e.g., Ilog Cplex1), has been challenged bythe use of libraries for Constraint Programming (CP), e.g., Ilog
Towards a Practical Engineering Tool for Rostering
"... The profitability and morale of many organizations (such as factories, hospitals and airlines) are affected by their ability to schedule their personnel properly. Sophisticated and powerful constraint solvers such as ILOG, CHIP, ECLiPSe, etc. have been demonstrated to be extremely effective on sched ..."
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The profitability and morale of many organizations (such as factories, hospitals and airlines) are affected by their ability to schedule their personnel properly. Sophisticated and powerful constraint solvers such as ILOG, CHIP, ECLiPSe, etc. have been demonstrated to be extremely effective on scheduling. Unfortunately, they require nontrivial expertise to use. This paper describes ZDCRostering, a constraintbased tool for personnel scheduling that addresses the software crisis and fills a void in the space of solvers. ZDCRostering is easier to use than the above constraintbased solvers and more effective than Microsoft’s Excel Solver. ZDCRostering is based on an opensource computeraided constraint programming package called ZDC, which decouples problem formulation (or modelling) from solution generation in constraint satisfaction. ZDC is equipped with a set of constraint algorithms, including Extended Guided Local Search, whose efficiency and effectiveness have been demonstrated in a wide range of applications. Our experiments show that ZDCRostering is capable of solving realisticsized and very tightlyconstrained problems efficiently. ZDCRostering demonstrates the feasibility of applying constraint satisfaction techniques to solving rostering problems, without having to acquire deep knowledge in constraint technology. 1.
unknown title
, 2001
"... A hybrid approach to extend DLbased reasoning with concrete domains ..."
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On a Constraint System for Lattice (Interval) Domains
, 2001
"... We present a generic framework for defining and solving interval constraints on any set of domains (finite or infinite) that are lattices. The approach is based on the use of a single constraint similar to the indexicals used by CLP over finite domains and on a particular generic definition of an in ..."
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We present a generic framework for defining and solving interval constraints on any set of domains (finite or infinite) that are lattices. The approach is based on the use of a single constraint similar to the indexicals used by CLP over finite domains and on a particular generic definition of an interval lattice built from the computation domain. We provide the theoretical foundations for this framework and a schematic procedure for the operational semantics. We also showby means of examples how lattice combinators can be used to construct new (compound) constraint solvers from existing solvers and how different solvers (possibly on distinct domains) can communicate and hence, cooperate in solving a problem. Finally, we introduce clp(L), a constraint logic programming language...
Scheduling Pilot Training
, 2000
"... We have constructed a scheduling component for activities with complex constraints, primarily designed for pilot training. Our component is called from planning tools, e.g. SARA (www.carmenta.se/eng/sara.html), used by the Swedish Air Force and SAS Flight Academy. Resource availability can change su ..."
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We have constructed a scheduling component for activities with complex constraints, primarily designed for pilot training. Our component is called from planning tools, e.g. SARA (www.carmenta.se/eng/sara.html), used by the Swedish Air Force and SAS Flight Academy. Resource availability can change suddenly, so new schedules may be needed quickly. One can prioritize activities that need changeable resources, to get robuster schedules. Pilots practice theory, simulation, and flying. Some activities are done jointly by a group, whose size depends on the activity. Equipment and instructors come in sets of alternative resources. The equipment forms a subset hierarchy. The instructors are theory instructors, simulator instructors or flight instructors, but these sets intersect, and a multiskilled instructor's availability depends on the skill. Resources have individual, timedependent, properties. Therefore, alternative resources cannot be treated as one discrete resource. But resource assignment cannot affect the duration of an activity. The schedule constraints are expressed in a special modelling language. The scheduling component accepts a schedule specification and computes feasible schedules. This paper describes how we implemented our scheduling component using ILOG Scheduler. For example, we eliminated resource symmetries and introduced subresources (resource usage implies subresource usage). We also let each activity select its resources just after its start time is bound, using a scheduleorpostpone algorithm (like IlcSetTimes) extended with a local solve() and some explicit constraint propagation.