Articles de revista
http://hdl.handle.net/2117/3626
2015-10-04T07:56:49ZA variational inequality reformulation of a congested transit assignment model by Cominetti, Correa, Cepeda, and Florian
http://hdl.handle.net/2117/28461
A variational inequality reformulation of a congested transit assignment model by Cominetti, Correa, Cepeda, and Florian
Codina Sancho, Esteve
In the paper by Cominetti and Correa (2001) [Common-lines and passenger assignment in congested transit networks. Transportation Science 35 (3), pp 250-267], an extension to the common-lines problem for general multidestination networks under congestion is analyzed. Their transit equilibrium assignment model allows for a full representation of congestion effects caused by the variation of effective frequencies experienced by passengers at transit stops. This model is the first to address these characteristics consistently with the concept of strategies. In a subsequent paper by Cepeda et al. (2006) [Cepeda, M., Cominetti, and R. Florian, M. (2006) A frequency-based assignment model for congested transit networks with strict capacity constraints: characterization and computation of equilibria. Trans. Res B 40, 437-459], the computation of equilibrium is performed heuristically by the minimization of a gap function, using the method of successive averages. In this paper, a reformulation of this congested transit equilibrium assignment model is performed, demonstrating that the problem can be expressed as an equivalent variational inequality. The case of strictly capacitated transit networks is explored under the scope of this new reformulation, and new, broader conditions for the existence of solutions to this congested transit assignment model are determined.
2012-08-02T00:00:00ZA Kalman filter approach for exploiting bluetooth traffic data when estimating time-dependent OD matrices
http://hdl.handle.net/2117/26824
A Kalman filter approach for exploiting bluetooth traffic data when estimating time-dependent OD matrices
Barceló Bugeda, Jaime; Montero Mercadé, Lídia; Bullejos, Manuel; Serch Muni, Oriol; Carmona, Carlos
Time-dependent origin–destination (OD) matrices are essential input for dynamic traffic models such as microscopic and mesoscopic traffic simulators. Dynamic traffic models also support real-time traffic management decisions, and they are traditionally used in the design and evaluation of advanced traffic traffic management and information systems (ATMS/ATIS). Time-dependent OD estimations are typically based either on Kalman filtering or on bilevel mathematical programming, which can be considered in most cases as ad hoc heuristics. The advent of the new information and communication technologies (ICT) provides new types of traffic data with higher quality and accuracy, which in turn allows new modeling hypotheses that lead to more computationally efficient algorithms. This article presents ad hoc, Kalman filtering procedures that explicitly exploit Bluetooth sensor traffic data, and it reports the numerical results from computational experiments performed at a network test site.
2013-05-17T00:00:00ZTravel time forecasting and dynamic of estimation in freeways based on bluetooth traffic monitoring
http://hdl.handle.net/2117/26526
Travel time forecasting and dynamic of estimation in freeways based on bluetooth traffic monitoring
Barceló Bugeda, Jaime; Montero Mercadé, Lídia; Marques, Laura; Carmona, Carlos
2010-01-01T00:00:00ZFix-and-relax-coordination for a multi-period location-allocation problem under uncertainty
http://hdl.handle.net/2117/23308
Fix-and-relax-coordination for a multi-period location-allocation problem under uncertainty
Albareda Sambola, Maria; Alonso Ayuso, Antonio; Escudero Bueno, Laureano; Fernández Aréizaga, Elena; Pizarro Romero, Celeste
A multi-period discrete facility location problem is introduced for a risk neutral strategy with uncertainty in the costs and some of the requirements along the planning horizon. A compact 0–1 formulation for the Deterministic Equivalent Model of the problem under two alternative strategies for the location decisions is presented. Furthermore, a new algorithmic matheuristic, Fix-and-Relax-Coordination, is introduced. This solution scheme is based on a specialization of the Branch-and-Fix Coordination methodology, which exploits the Nonanticipativity Constraints and uses the Twin Node Family concept. The results of an extensive computational experience allow to compare the alternative modeling strategies and assess the effectiveness of the proposed approach versus the plain use of a state-of-the-art MIP solver.
2013-12-01T00:00:00ZMultiperiod location-routing with decoupled time scales
http://hdl.handle.net/2117/17129
Multiperiod location-routing with decoupled time scales
Albareda Sambola, Maria; Fernández Aréizaga, Elena; Nickel, Stefan
This paper focuses on a multiperiod discrete facility location problem where transportation costs are considered together with location costs to design the operating facility pattern along a time horizon. The problem captures the difference in the scope of the location and routing decisions by considering different scales within the time horizon. Thus, solutions to this problem reflect the stability of locational decisions along time. The high complexity of this problem makes it impossible to be solved in practice with commercial software. For this reason, an approximation based on replacing vehicle routes by spanning trees is proposed, and its capability for providing good quality solutions is assessed in a series of computational experiments.
2012-03-01T00:00:00ZGeneral network design : a unified view of combined location and network design problems
http://hdl.handle.net/2117/16396
General network design : a unified view of combined location and network design problems
Contreras Aguilar, Iván; Fernández Aréizaga, Elena
This paper presents a unified framework for the general network design problem which encompasses several classical problems involving combined location and network design decisions. In some of these problems the service demand relates users and facilities, whereas in other cases the service demand relates pairs of users between them, and facilities are used to consolidate and re-route flows between users. Problems of this type arise in the design of transportation and telecommunication systems and include well-known problems such as location-network design problems, hub location problems, extensive facility location problems, tree-star location problems and cycle-star location problems, among others. Relevant modeling aspects, alternative formulations and possible algorithmic strategies are presented and analyzed.
2011-06-16T00:00:00ZMinimizing the maximum travel time in a combined model of facility location and network design
http://hdl.handle.net/2117/16394
Minimizing the maximum travel time in a combined model of facility location and network design
Contreras Aguilar, Iván; Fernández Aréizaga, Elena; Reineltc, Gerhard
This paper presents a combined Facility Location/Network Design Problem which simultaneously considers the location of facilities and the design of its underlying network so as to minimize the maximum customer-facility travel time. The model generalizes the classical p-center problem and has various applications in regional planning, distribution, telecommunications, emergency systems, and other areas. Two mixed integer programming formulations are presented and compared. Several valid inequalities are derived for the most promising of these formulations to strengthen its LP relaxation bound and to reduce the enumeration tree. Numerical results of a series of computational experiments for instances with up to 100 nodes and 500 candidate links are reported.
2012-12-01T00:00:00ZModeling and solving a variant of the mixed-model sequencing problem with work overload minimisation and regularity constraints. An application in Nissan’s Barcelona Plant
http://hdl.handle.net/2117/15894
Modeling and solving a variant of the mixed-model sequencing problem with work overload minimisation and regularity constraints. An application in Nissan’s Barcelona Plant
Bautista Valhondo, Joaquín; Cano Pérez, Alberto; Alfaro Pozo, Rocío
In this paper, we present an extension to the mixed-model sequencing problem with work overload minimisation (MMSP-W) for production lines with serial workstations and parallel homogeneous processors. The extension is intended to meet the industrial need to sequence various products so that the work required and completed at the workstations over time is as constant as possible. Several approaches are proposed to formulate the problem, giving rise to different models. Four models are selected, and their performances are compared after running the Gurobi solver, using instances from the literature and a case study of the Nissan powertrain plant in Barcelona.
2012-09-15T00:00:00ZA scatter search based hyper-heuristic for sequencing a mixed-model assembly line, Journal of Heuristics
http://hdl.handle.net/2117/15277
A scatter search based hyper-heuristic for sequencing a mixed-model assembly line, Journal of Heuristics
Cano-Belman, J; Ríos-Mercado, Roger Z.; Bautista Valhondo, Joaquín
We address a mixed-model assembly-line sequencing problem with work
overload minimization criteria.We consider time windows in work stations of the assembly
line (closed stations) and different versions of a product to be assembled in the
line, which require different processing time according to the work required in each
work station. In a paced assembly line, products are feeded in the line at a predetermined
constant rate (cycle time). Then, if many products with processing time greater
than cycle time are feeded consecutively, work overload can be produced when the
worker has insufficient time to finish his/her job. We propose a scatter search based
hyper-heuristic for this NP-hard problem. In the low-level, the procedure makes use
of priority rules through a constructive procedure. Computational experiments over
a wide range of instances from the literature show the effectiveness of the proposed
hyper-heuristics when compared to existing heuristics. The relevance of the priority
rules was evaluated as well.
2010-12-01T00:00:00ZMultiobjective memetic algorithms for time and space assembly line balancing
http://hdl.handle.net/2117/14734
Multiobjective memetic algorithms for time and space assembly line balancing
Chica, Manuel; Cordon, Oscar; Damas, Sergio; Bautista Valhondo, Joaquín
This paper presents three proposals of multiobjective memetic algorithms to solve a more realistic extension of a classical industrial problem: time and space assembly line balancing. These three proposals are, respectively, based on evolutionary computation, ant colony optimisation, and greedy randomised search procedure. Different variants of these memetic algorithms have been developed and compared in order to determine the most suitable intensification–diversification trade-off for the memetic search process. Once a preliminary study on nine well-known problem instances is accomplished with a very good performance, the proposed memetic algorithms are applied considering real-world data from a Nissan plant in Barcelona (Spain). Outstanding approximations to the pseudo-optimal non-dominated solution set were achieved for this industrial case study.
2012-01-11T00:00:00Z