Original scientific paper A water distribution system is an essential component of any urban infr... more Original scientific paper A water distribution system is an essential component of any urban infrastructure system. Its design is commonly a hard task mainly due to the presence of several complex interrelated parameters. Among others, some parameters to study are the water demand, pressure requirements, topography, location of resources, system reliability, and energy uses. In this paper, we focus on a real case of water distribution system in order to minimize installation costs by satisfying the given system requirements. We solve the problem by using state-of-the-art Constraint Programming techniques combined with Interval Analysis for rigorously handling continuous decision variables. Experimental results demonstrate the feasibility of the proposed approach, where the global optimum is reached in all instances and in reasonable runtime.
Constraint manipulation using rewrite rules and strategies
Proceedings of the Second ESSLLI Student Session, …, 1997
We are interested in constraint manipulation using rule-based algorithms because of the explicit ... more We are interested in constraint manipulation using rule-based algorithms because of the explicit distinction made in this approach between deduction rules and control. We associate actions with rewrite rules and control with strategies that establish the order of ...
2009 Eighth Mexican International Conference on Artificial Intelligence, 2009
Constraint Programming is a powerful paradigm for solving Combinatorial Problems. In this solver ... more Constraint Programming is a powerful paradigm for solving Combinatorial Problems. In this solver approach, Enumeration Strategies are crucial for resolution performances. In a previous work, we proposed a framework to reactively change strategies showing bad performances, and to use metabacktracks to restore better states when bad decisions were made. In this paper, we design and evaluate strategies to improve resolution performances of a set of problems. Experimental results show the effectiveness of our approach.
A fuel-air explosive weapon launched from a remote distance is used for clearing minefields. A se... more A fuel-air explosive weapon launched from a remote distance is used for clearing minefields. A set timing pattern in the operation of the minefield clearance round permits varied range through retarding the length of time that a programed sequence of events occurs at the launch site. Upon flight, the round follows a predetermined pattern in deployment of a parachute, firing cloud detonators and initiation of a burster charge. An extendable probe at the front of the round permits detonation at a predetermined level above ground. The descent by parachute provides a relatively stable launching platform for cloud detonators if they are fired prior to the burster charge detonation for dispersal of the fuel-air cloud.
We present experimental results of solving mathematical models, using very efficient complete and... more We present experimental results of solving mathematical models, using very efficient complete and incomplete techniques, for designing balanced academic curricula. Solutions to these models give curricula with academic load for each period as similar as possible. Based on this work, a software tool has been developed to help administratives as well as students in the planning of academic curricula.
This paper captures our experience developing Algorithms to solve Combinatorial Problems using di... more This paper captures our experience developing Algorithms to solve Combinatorial Problems using different techniques. Because it is a Software Engineering problem, then to find better ways of developing algorithms, solvers and metaheuristics is our interest too. Here, we fixed some concepts from Knowledge Management and Software Engineering applied in our work.
Integrating Lookahead and Post Processing Procedures with ACO for Solving Set Partitioning and Covering Problems
Lecture Notes in Computer Science, 2006
Set Covering Problems and Set Partitioning Problems can model several real life situations. In th... more Set Covering Problems and Set Partitioning Problems can model several real life situations. In this paper, we solve some bench- marks of them with Ant Colony Optimization algorithms and some hy- bridizations of Ant Colony Optimization with Constraint Programming techniques. A lookahead mechanism allows the incorporation of informa- tion on the anticipated decisions that are beyond the immediate choice horizon.
This article analyzes the performance of Ant Colony Optimization algorithms on the resolution of ... more This article analyzes the performance of Ant Colony Optimization algorithms on the resolution of Crew Pairing Problem, one of the most critical processes in airline management operations. Furthermore, we explore the hybridization of Ant algorithms with Constraint Programming techniques. We show that, for the instances tested from Beasley's OR-Library, the use of this kind of hybrid algorithms obtains good results compared to the best performing metaheuristics in the literature.
Decomposition Approach to Solve Dial-a-Ride Problems Using Ant Computing and Constraint Programming
Lecture Notes in Computer Science
In this paper we solve the Dial-A-Ride Problem (DARP). The main objective of the DARP is to minim... more In this paper we solve the Dial-A-Ride Problem (DARP). The main objective of the DARP is to minimize operation costs for renting pieces of work from the transportation service providers. The resolution approach considered in this work, starting from a network formulation of the DARP, decomposes the problem in two phases: Clustering and Chaining. We model both phases like a
Integration of Constraint Programming and Metaheuristics
Lecture Notes in Computer Science
Our research is focused on developing hybrid solvers for Combinatorial Optimization Problems. We ... more Our research is focused on developing hybrid solvers for Combinatorial Optimization Problems. We are concerned with the design of hybrid resolution approaches including Constraint Programming and Metaheuristics. We have been working on that area during the last years, exploring the different issues involved in algorithm design, implementation, tuning and experimental evaluation. We provide an overview of the research we have
Adaptive Enumeration Strategies and Metabacktracks for Constraint Solving
Lecture Notes in Computer Science, 2006
In Constraint Programming, enumeration strategies are crucial for resolution performances. The ef... more In Constraint Programming, enumeration strategies are crucial for resolution performances. The effect of strategies is generally unpredictable. In a previous work, we proposed to dynamically change strategies showing bad performances, and to use metabacktrack to ...
A fuel-air explosive weapon launched from a remote distance is used for clearing minefields. A se... more A fuel-air explosive weapon launched from a remote distance is used for clearing minefields. A set timing pattern in the operation of the minefield clearance round permits varied range through retarding the length of time that a programed sequence of events occurs at the launch site. Upon flight, the round follows a predetermined pattern in deployment of a parachute, firing cloud detonators and initiation of a burster charge. An extendable probe at the front of the round permits detonation at a predetermined level above ground. The descent by parachute provides a relatively stable launching platform for cloud detonators if they are fired prior to the burster charge detonation for dispersal of the fuel-air cloud.
We present experimental results of solving mathematical models, using very efficient complete and... more We present experimental results of solving mathematical models, using very efficient complete and incomplete techniques, for designing balanced academic curricula. Solutions to these models give curricula with academic load for each period as similar as possible. Based on this work, a software tool has been developed to help administratives as well as students in the planning of academic curricula.
This paper captures our experience developing Algorithms to solve Combinatorial Problems using di... more This paper captures our experience developing Algorithms to solve Combinatorial Problems using different techniques. Because it is a Software Engineering problem, then to find better ways of developing algorithms, solvers and metaheuristics is our interest too. Here, we fixed some concepts from Knowledge Management and Software Engineering applied in our work.
Integrating Lookahead and Post Processing Procedures with ACO for Solving Set Partitioning and Covering Problems
Lecture Notes in Computer Science, 2006
Set Covering Problems and Set Partitioning Problems can model several real life situations. In th... more Set Covering Problems and Set Partitioning Problems can model several real life situations. In this paper, we solve some bench- marks of them with Ant Colony Optimization algorithms and some hy- bridizations of Ant Colony Optimization with Constraint Programming techniques. A lookahead mechanism allows the incorporation of informa- tion on the anticipated decisions that are beyond the immediate choice horizon.
This article analyzes the performance of Ant Colony Optimization algorithms on the resolution of ... more This article analyzes the performance of Ant Colony Optimization algorithms on the resolution of Crew Pairing Problem, one of the most critical processes in airline management operations. Furthermore, we explore the hybridization of Ant algorithms with Constraint Programming techniques. We show that, for the instances tested from Beasley's OR-Library, the use of this kind of hybrid algorithms obtains good results compared to the best performing metaheuristics in the literature.
Decomposition Approach to Solve Dial-a-Ride Problems Using Ant Computing and Constraint Programming
Lecture Notes in Computer Science
In this paper we solve the Dial-A-Ride Problem (DARP). The main objective of the DARP is to minim... more In this paper we solve the Dial-A-Ride Problem (DARP). The main objective of the DARP is to minimize operation costs for renting pieces of work from the transportation service providers. The resolution approach considered in this work, starting from a network formulation of the DARP, decomposes the problem in two phases: Clustering and Chaining. We model both phases like a
Integration of Constraint Programming and Metaheuristics
Lecture Notes in Computer Science
Our research is focused on developing hybrid solvers for Combinatorial Optimization Problems. We ... more Our research is focused on developing hybrid solvers for Combinatorial Optimization Problems. We are concerned with the design of hybrid resolution approaches including Constraint Programming and Metaheuristics. We have been working on that area during the last years, exploring the different issues involved in algorithm design, implementation, tuning and experimental evaluation. We provide an overview of the research we have
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Papers by Carlos Castro