GNOM - Grup d'Optimització Numèrica i Modelització

 


El treball del grup comprèn l'optimització numèrica, la modelització de problemes resolubles amb optimització, i l'aplicació de tècniques adients a problemes de l'enginyeria, la indústria, la logística i les tecnologies de la informació. L'optimització numèrica inclou l'estudi de les propietats del problemes estudiats, l'anàlisi de nous algorismes d'optimització (lineal, no lineal, contínua, entera i combinatòria), el desenvolupament de procediments numèrics per a la seva implementació computacional eficient i la comparació amb algorismes previs, si existeixen. La part de modelització implica la cerca de formulacions escaients que permetin la resolució de problemes reals, sovint de gran dimensió. Els problemes reals en que el grup està treballant actualment són: protecció i privacitat de dades estadístiques; i generació òptima d'electricitat en un entorn multimercat.

The group works on both the numerical optimisation and the modelling of problems that can be solved through optimisation. Its work on numerical optimisation includes the analysis of new optimisation algorithms (linear, nonlinear, continuous and integer) and their convergence, the development of numerical procedures for their efficient computational implementation, and the comparison to existing algorithms. The work on modelling focuses on the solution of real problems, which are often large-scale, by finding an equivalentmathematical formulation leading to an optimisation problem, and applying a suitable solver, that has either been specially developed or is commercially available. The modelling languages that are available are used.

The group works on both the numerical optimisation and the modelling of problems that can be solved through optimisation. Its work on numerical optimisation includes the analysis of new optimisation algorithms (linear, nonlinear, continuous and integer) and their convergence, the development of numerical procedures for their efficient computational implementation, and the comparison to existing algorithms. The work on modelling focuses on the solution of real problems, which are often large-scale, by finding an equivalentmathematical formulation leading to an optimisation problem, and applying a suitable solver, that has either been specially developed or is commercially available. The modelling languages that are available are used.

Recent Submissions

  • Location routing problems on trees 

    Aráoz Durand, Julián Arturo; Fernández Aréizaga, Elena; Rueda, Salvador (2019-04-30)
    Article
    Restricted access - publisher's policy
    This paper addresses combined location/routing problems defined on trees, where not all vertices have to be necessarily visited. A mathematical programming formulation is presented, which has the integrality property. The ...

  • The effects of lithium sulfur battery ageing on second-life possibilities and environmental life cycle assessment studies 

    Wolff, Deidre; Canals Casals, Lluc; Benveniste Pérez, Gabriela; Corchero García, Cristina; Trilla Romero, Lluís (2019-01-01)
    Article
    Open Access
    The development of Li-ion batteries has enabled the re-entry of electric vehicles into the market. As car manufacturers strive to reach higher practical specific energies (550 Wh/kg) than what is achievable for Li-ion ...

  • Does evidence support the high expectations placed in precision medicine? A bibliographic review 

    Cortés Martínez, Jordi; González Alastrué, José Antonio; Medina, María Nuncia; Vogler, Markus; Vilaró Pacheco, Marta; Elmore, Matthew; Senn, Stephen John; Campbell, Michael J.; Cobo Valeri, Erik (2018-01-09)
    Article
    Open Access
    Background: Precision medicine is the Holy Grail of interventions that aretailored to a patient’s individual characteristics.  However, the conventional design of randomized trials assumes that each individual benefits  ...

  • The stratified p-center problem 

    Albareda Sambola, Maria; Martínez Merino, Luisa I.; Rodríguez Chía, Antonio Manuel (2019-08-01)
    Article
    Restricted access - publisher's policy
    This work presents an extension of the discrete p-center problem. In this new model, called Stratified p-Center Problem (SpCP), the demand is concentrated in a set of sites and the population of these sites is divided into ...

  • Combining statistical learning with metaheuristics for the multi-depot vehicle routing problem with market segmentation 

    Ferrer Biosca, Alberto; Calvet Liñán, Laura; Juan, Angel A.; Masip Rodó, David; Gomes, M. Isabel (2016-02)
    Article
    Open Access
    In real-life logistics and distribution activities it is usual to face situations in which the distribution of goods has to be made from multiple warehouses or depots to the nal customers. This problem is known as the ...

  • Reused second life batteries for aggregated demand response services 

    Canals Casals, Lluc; Barbero, Mattia; Corchero García, Cristina (2019-03-01)
    Article
    Restricted access - publisher's policy
    The electric vehicle is presented as an environmental friendly alternative to common vehicles and as the future of transportation. However, car manufacturers consider that electric vehicle batteries are not useful for ...

  • A comparative note on the relaxation algorithms for the linear semi-infinite feasibility problem 

    Ferrer Biosca, Alberto; Goberna Torrent, Miguel Ángel; González Gutiérrez, Enrique; Todorov, Maxim Ivanov (2017-11)
    Article
    Open Access
    The problem (LFP) of finding a feasible solution to a given linear semi-infinite system arises in different contexts. This paper provides an empirical comparative study of relaxation algorithms for (LFP). In this study ...

  • Reformulated acyclic partitioning for rail-rail containers transshipment 

    Albareda Sambola, Maria; Marín Pérez, Alfredo; Rodríguez Chía, Antonio Manuel (Elsevier, 2019-08-16)
    Article
    Restricted access - publisher's policy
    Many rail terminals have loading areas that are properly equipped to move containers between trains. With the growing throughput of these terminals all the trains involved in a sequence of such movements may not ¿t in the ...

  • Tools used to assess the quality of peer review reports: a methodological systematic review 

    Superchi, Cecilia; González Alastrué, José Antonio; Solà, Ivan; Cobo Valeri, Erik; Hren, Darko; Boutron, Isabelle (2019-03-06)
    Article
    Open Access
    Background A strong need exists for a validated tool that clearly defines peer review report quality in biomedical research, as it will allow evaluating interventions aimed at improving the peer review process in ...

  • A specialized interior-point algorithm for huge minimum convex cost flows in bipartite networks 

    Castro Pérez, Jordi; Nasini, Stefano (2019-01-28)
    External research report
    Open Access
    The computation of the Newton direction is the most time consuming step of interior-point methods. This direction was efficiently computed by a combination of Cholesky factorizations and conjugate gradients in a specialized ...

  • Exact calculation of network robustness 

    Lordan González, Oriol; Albareda Sambola, Maria (2019-03)
    Article
    Restricted access - publisher's policy
    Finding the most critical nodes regarding network connectivity has attracted the attention of many researchers in infrastructure networks, power grids, transportation networks and physics in complex networks. Static ...

  • A branch-and-cut algorithm for the multidepot rural postman problem 

    Fernández Aréizaga, Elena; Laporte, Gilbert; Rodríguez Pereira, Jessica (2018-03)
    Article
    Open Access
    This paper considers the Multidepot Rural Postman Problem, an extension of the classical Rural Postman Problem in which there are several depots instead of only one. The aim is to construct a minimum cost set of routes ...

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