BIRD, BCAM's Institutional Repository Data
http://bird.bcamath.org:80
The BIRD digital repository system captures, stores, indexes, preserves, and distributes digital research material.Wed, 20 Sep 2017 01:42:09 GMT2017-09-20T01:42:09ZGoal-Oriented p-Adaptivity using Unconventional Error Representations for a 1D Steady State Convection-Diffusion Problem
http://hdl.handle.net/20.500.11824/732
Goal-Oriented p-Adaptivity using Unconventional Error Representations for a 1D Steady State Convection-Diffusion Problem
Pardo D.; Darrigrand V.; Rodríguez-Rozas A.; Muga I.
This work proposes the use of an alternative error representation for Goal-Oriented Adaptivity (GOA) in context of steady state convection dominated diffusion problems. It introduces an arbitrary operator for the computation of the error of an alternative dual problem. From the new representation, we derive element-wise estimators to drive the adaptive algorithm. The method is applied to a one dimensional (1D) steady state convection dominated diffusion problem with homogeneous Dirichlet boundary conditions. This problem exhibits a boundary layer that produces a loss of numerical stability. The new error representation delivers sharper error bounds. When applied to a $p$-GOA Finite Element Method (FEM), the alternative error representation captures earlier the boundary layer, despite the existing spurious numerical oscillations.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/20.500.11824/7322017-01-01T00:00:00ZSPECTRAL ASYMPTOTICS FOR $\delta$-INTERACTIONS ON SHARP CONES
http://hdl.handle.net/20.500.11824/731
SPECTRAL ASYMPTOTICS FOR $\delta$-INTERACTIONS ON SHARP CONES
Ourmières-Bonafos T.; Pankrashkin K.; Pizzichillo F.
We investigate the spectrum of three-dimensional Schr\"odinger operators with $\delta$-interactions of constant strength supported on circular cones. As shown in earlier works, such operators have infinitely many eigenvalues below the threshold of the essential spectrum. We focus on spectral properties for sharp cones, that is when the cone aperture goes to zero, and we describe the asymptotic behavior of the eigenvalues and of the eigenvalue counting function. A part of the results are given in terms of numerical constants appearing as solutions of transcendental equations involving modified Bessel functions.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/20.500.11824/7312017-01-01T00:00:00ZAn efficient evolutionary algorithm for the orienteering problem
http://hdl.handle.net/20.500.11824/730
An efficient evolutionary algorithm for the orienteering problem
Kobeaga G.; Merino M.; Lozano J.A.
This paper deals with the Orienteering Problem, which is a routing problem. In the Orienteering Problem, each node has a profit assigned and the goal is to find the route that maximizes the total collected profit subject to a limitation on the total route distance. To solve this problem, we propose an evolutionary algorithm, whose key characteristic is to maintain unfeasible solutions during the search. Furthermore, it includes a novel solution codification for the Orienteering Problem, a novel heuristic for node inclusion in the route, an adaptation of the Edge Recombination crossover developed for the Travelling Salesperson Problem, specific operators to recover the feasibility of solutions when required, and the use of the Lin-Kernighan heuristic to improve the route lengths. We compare our algorithm with three state-of-the-art algorithms for the problem on 344 benchmark
instances, with up to 7397 nodes. The results show a competitive behavior of our approach in instances of low-medium dimensionality, and outstanding results in the large dimensionality instances reaching new best known solutions with lower computational time than the state-of-the-art algorithms.
Wed, 06 Sep 2017 00:00:00 GMThttp://hdl.handle.net/20.500.11824/7302017-09-06T00:00:00ZICCS 2017 Workshop on Agent-Based Simulations, Adaptive Algorithms and Solvers
http://hdl.handle.net/20.500.11824/729
ICCS 2017 Workshop on Agent-Based Simulations, Adaptive Algorithms and Solvers
Byrski A.; Paszyński M.; Schaefer R.; Calo VM.; Pardo D.
This workshop seeks to integrate results from different domains of computer science, computational science, and mathematics. We welcome simulation papers, either hard simulations using finite element or finite difference methods, or soft simulations by means of evolutionary computations, and related methods. The workshop focuses on simulations performed by using (a) agent-oriented systems; or (b) adaptive algorithms. Simulations performed by other kind of systems are also welcome. An agent-oriented system seems are attractive tools useful for numerous domains of applications. Adaptive algorithms significantly decrease on the computational cost by investing computational resources when needed by the problem.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/20.500.11824/7292017-01-01T00:00:00Z