All Outputs (89)

Multi-start methods for the capacitated clustering problem (2017)
Presentation / Conference Contribution
Martinez-Gavara, A., Campos, V., Landa-Silva, D., & Marti, R. (2017). Multi-start methods for the capacitated clustering problem. In Metaheuristics: Proceeding of the MIC and MAEB 2017 Conferences

In this work, we investigate the adaptation of the Greedy Randomized Adaptive Search Procedure (GRASP) and Iterated Greedy methodologies to the Capacitated Clustering Problem (CCP). In particular, we focus on the effect of the balance between randomi... Read More about Multi-start methods for the capacitated clustering problem.

Randomized heuristics for the Capacitated Clustering Problem (2017)
Journal Article
Martinez-Gavara, A., Landa-Silva, D., Campos, V., & Marti, R. (2017). Randomized heuristics for the Capacitated Clustering Problem. Information Sciences, 417, https://doi.org/10.1016/j.ins.2017.06.041

In this paper, we investigate the adaptation of the Greedy Randomized Adaptive Search Procedure (GRASP) and Iterated Greedy methodologies to the Capacitated Clustering Problem (CCP). In particular, we focus on the effect of the balance between random... Read More about Randomized heuristics for the Capacitated Clustering Problem.

Solving a large real-world bus driver scheduling problem with a multi-assignment based heuristic algorithm (2017)
Journal Article
Constantino, A. A., de Mendonca, C. F., de Araujo, S. A., Landa-Silva, D., Calvi, R., & dos Santos, A. F. (2017). Solving a large real-world bus driver scheduling problem with a multi-assignment based heuristic algorithm. Journal of Universal Computer Science, 23(5),

The bus driver scheduling problem (BDSP) under study consists in finding a set of duties that covers the bus schedule from a Brazilian public transportation bus company with the objective of minimizing the total cost. A deterministic 2-phase heuristi... Read More about Solving a large real-world bus driver scheduling problem with a multi-assignment based heuristic algorithm.

ES-Rank: evolution strategy learning to rank approach (2017)
Presentation / Conference Contribution
Ibrahim, O. A. S., & Landa-Silva, D. (2017). ES-Rank: evolution strategy learning to rank approach. In SAC '17: Proceedings of the Symposium on Applied Computing (944-950). https://doi.org/10.1145/3019612.3019696

Learning to Rank (LTR) is one of the current problems in Information Retrieval (IR) that attracts the attention from researchers. The LTR problem is mainly about ranking the retrieved documents for users in search engines, question answering and prod... Read More about ES-Rank: evolution strategy learning to rank approach.

A technique based on trade-off maps to visualise and analyse relationships between objectives in optimisation problems (2017)
Journal Article
Pinheiro, R. L., Landa-Silva, D., & Atkin, J. (2017). A technique based on trade-off maps to visualise and analyse relationships between objectives in optimisation problems. Journal of Multi-Criteria Decision Analysis, 24(1-2), 37-56. https://doi.org/10.1002/mcda.1604

Understanding the relationships between objectives in a multiobjective optimisation problem is important for developing tailored and efficient solving techniques. In particular, when tackling combinatorial optimisation problems with many objectives t... Read More about A technique based on trade-off maps to visualise and analyse relationships between objectives in optimisation problems.

An investigation of heuristic decomposition to tackle workforce scheduling and routing with time-dependent activities constraints (2017)
Presentation / Conference Contribution
Laesanklang, W., Landa-Silva, D., & Castillo-Salazar, J. A. (2017). An investigation of heuristic decomposition to tackle workforce scheduling and routing with time-dependent activities constraints. In B. Vitoriano, & G. Parlier (Eds.), ICORES 2016: Operations research and enterprise systems (239-260). https://doi.org/10.1007/978-3-319-53982-9_14

This paper presents an investigation into the application of heuristic decomposition and mixed-integer programming to tackle workforce scheduling and routing problems (WSRP) that involve time dependent activities constraints. These constraints refer... Read More about An investigation of heuristic decomposition to tackle workforce scheduling and routing with time-dependent activities constraints.

Dynamic programming with approximation function for nurse scheduling (2016)
Journal Article
Shi, P., & Landa-Silva, D. (2016). Dynamic programming with approximation function for nurse scheduling. Lecture Notes in Artificial Intelligence, 10122, 269-280. https://doi.org/10.1007/978-3-319-51469-7_23

Although dynamic programming could ideally solve any combinatorial optimization problem, the curse of dimensionality of the search space seriously limits its application to large optimization problems. For example, only few papers in the literature h... Read More about Dynamic programming with approximation function for nurse scheduling.

An application programming interface with increased performance for optimisation problems data (2016)
Journal Article
Pinheiro, R. L., Landa-Silva, D., Qu, R., Constantino, A. A., & Yanaga, E. (in press). An application programming interface with increased performance for optimisation problems data. Journal of Management Analytics, 3(4), https://doi.org/10.1080/23270012.2016.1233514

An optimisation problem can have many forms and variants. It may consider different objectives, constraints, and variables. For that reason, providing a general application programming interface (API) to handle the problem data efficiently in all sce... Read More about An application programming interface with increased performance for optimisation problems data.

Decomposition techniques with mixed integer programming and heuristics for home healthcare planning (2016)
Journal Article
Laesanklang, W., & Landa-Silva, D. (2017). Decomposition techniques with mixed integer programming and heuristics for home healthcare planning. Annals of Operations Research, 256(1), 93-127. https://doi.org/10.1007/s10479-016-2352-8

We tackle home healthcare planning scenarios in the UK using decomposition methods that incorporate mixed integer programming solvers and heuristics. Home healthcare planning is a difficult problem that integrates aspects from scheduling and routing.... Read More about Decomposition techniques with mixed integer programming and heuristics for home healthcare planning.

A Genetic Algorithm for a Workforce Scheduling and Routing Problem (2016)
Presentation / Conference Contribution
Algethami, H., Pinheiro, R. L., & Landa-Silva, D. (2016). A Genetic Algorithm for a Workforce Scheduling and Routing Problem.

The Workforce Scheduling and Routing Problem refers to the assignment of personnel to visits across various geographical locations. Solving this problem demands tackling scheduling and routing constraints while aiming to minimise the total operationa... Read More about A Genetic Algorithm for a Workforce Scheduling and Routing Problem.

Towards an efficient API for optimisation problems data (2016)
Presentation / Conference Contribution
Pinheiro, R. L., Landa-Silva, D., Qu, R., Yanaga, E., & Constantino, A. A. (2016, April). Towards an efficient API for optimisation problems data. Presented at ICEIS 2016 - Proceedings of the 18th International Conference on Enterprise Information Systems, Rome, Italy

The literature presents many application programming interfaces (APIs) and frameworks that provide state of the art algorithms and techniques for solving optimisation problems. The same cannot be said about APIs and frameworks focused on the problem... Read More about Towards an efficient API for optimisation problems data.

Hyper-volume evolutionary algorithm (2016)
Journal Article
Le, K. N., & Landa-Silva, D. (2016). Hyper-volume evolutionary algorithm

We propose a multi-objective evolutionary algorithm (MOEA), named the Hyper-volume Evolutionary Algorithm (HVEA). The algorithm is characterised by three components. First, individual fitness evaluation depends on the current Pareto front, specifical... Read More about Hyper-volume evolutionary algorithm.

Mixed integer programming with decomposition for workforce scheduling and routing with time-dependent activities constraints (2016)
Presentation / Conference Contribution
Laesanklang, W., Landa-Silva, D., & Castillo-Salazar, J. A. (2016). Mixed integer programming with decomposition for workforce scheduling and routing with time-dependent activities constraints.

We present a mixed integer programming decomposition approach to tackle workforce scheduling and routing problems (WSRP) that involve time-dependent activities constraints. The proposed method is called repeated decomposition with conflict repair (RD... Read More about Mixed integer programming with decomposition for workforce scheduling and routing with time-dependent activities constraints.

Extended decomposition for mixed integer programming to solve a workforce scheduling and routing problem (2015)
Presentation / Conference Contribution
Laesanklang, W., Pinheiro, R. L., Algethami, H., & Landa-Silva, D. (2015). Extended decomposition for mixed integer programming to solve a workforce scheduling and routing problem. In D. D. Werra, G. H. Parlier, & B. Vitoriano (Eds.), Operations research and enterprise systems: 4th International Conference, ICORES 2015, Lisbon, Portugal, January 10-12, 2015: revised selected papers (191–211). https://doi.org/10.1007/978-3-319-27680-9_12

© Springer International Publishing Switzerland 2015. We propose an approach based on mixed integer programming (MIP) with decomposition to solve a workforce scheduling and routing problem, in which a set of workers should be assigned to tasks that a... Read More about Extended decomposition for mixed integer programming to solve a workforce scheduling and routing problem.

A Variable Neighbourhood Search for nurse scheduling with balanced preference satisfaction (2015)
Presentation / Conference Contribution
Constantino, A. A., Tozzo, E., Pinheiro, R. L., Landa-Silva, D., & Romão, W. (2015). A Variable Neighbourhood Search for nurse scheduling with balanced preference satisfaction.

The nurse scheduling problem (NSP) is a combinatorial optimisation problem widely tackled in the literature. Recently, a new variant of this problem was proposed, called nurse scheduling problem with balanced preference satisfaction (NSPBPS). This pa... Read More about A Variable Neighbourhood Search for nurse scheduling with balanced preference satisfaction.

Term frequency with average term occurrences for textual information retrieval (2015)
Journal Article
Ibrahim, O., & Landa-Silva, D. (2016). Term frequency with average term occurrences for textual information retrieval. Soft Computing, 20(8), 3045-3061. https://doi.org/10.1007/s00500-015-1935-7

In the context of Information Retrieval (IR) from text documents, the term-weighting scheme (TWS) is a key component of the matching mechanism when using the vector space model (VSM). In this paper we propose a new TWS that is based on computing the... Read More about Term frequency with average term occurrences for textual information retrieval.

A variable neighbourhood search for the workforce scheduling and routing problem (2015)
Presentation / Conference Contribution
Pinheiro, R. L., Landa-Silva, D., & Atkin, J. (2015). A variable neighbourhood search for the workforce scheduling and routing problem. In N. Pillay, A. P. Engelbrecht, A. Abraham, M. C. du Plessis, V. Snášel, & A. K. Muda (Eds.), Advances in nature and biologically inspired computing: proceedings of the 7th World Congress on Nature and Biologically Inspired Computing, NaBIC2015, in Pietermaritzburg, South Africa, held December 01-03, 2015 (247–259). https://doi.org/10.1007/978-3-319-27400-3_22

The workforce scheduling and routing problem (WSRP) is a combinatorial optimisation problem where a set of workers must perform visits to geographically scattered locations. We present a Variable Neighbourhood Search (VNS) metaheuristic algorithm to... Read More about A variable neighbourhood search for the workforce scheduling and routing problem.

A hybrid GRASP-VNS for Ship Routing and Scheduling Problem with Discretized Time Windows (2015)
Journal Article
Armas, J. D., Lalla-Ruiz, E., Expósito-Izquierdo, C., Landa-Silva, D., & Melián-Batista, B. (2015). A hybrid GRASP-VNS for Ship Routing and Scheduling Problem with Discretized Time Windows. Engineering Applications of Artificial Intelligence, 45, https://doi.org/10.1016/j.engappai.2015.07.013

This paper addresses the Ship Routing and Scheduling Problem with Discretized Time Windows. Being one of the most relevant and challenging problems faced by decision makers from shipping companies, this tramp shipping problem lies in determining the... Read More about A hybrid GRASP-VNS for Ship Routing and Scheduling Problem with Discretized Time Windows.

(1+1)-Evolutionary gradient strategy to evolve global term weights in information retrieval (2015)
Presentation / Conference Contribution
Ibrahim, O. A. S., & Landa-Silva, D. (2016). (1+1)-Evolutionary gradient strategy to evolve global term weights in information retrieval. In P. Angelov, A. Gegov, C. Jayne, & Q. Shen (Eds.), Advances in computational intelligence systems: contributions presented at the 16th UK Workshop on Computational Intelligence, September 7–9, 2016, Lancaster, UK (387–405). https://doi.org/10.1007/978-3-319-46562-3_25

In many contexts of Information Retrieval (IR), term weights play an important role in retrieving the relevant documents responding to users' queries. The term weight measures the importance or the information content of a keyword existing in the doc... Read More about (1+1)-Evolutionary gradient strategy to evolve global term weights in information retrieval.

Analysis of objectives relationships in multiobjective problems using trade-off region maps (2015)
Presentation / Conference Contribution
Pinheiro, R. L., Landa-Silva, D., & Atkin, J. (2015). Analysis of objectives relationships in multiobjective problems using trade-off region maps.

Understanding the relationships between objectives in many-objective optimisation problems is desirable in order to develop more effective algorithms. We propose a techniquefor the analysis and visualisation of complex relationships between many (thr... Read More about Analysis of objectives relationships in multiobjective problems using trade-off region maps.