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http://hdl.handle.net/2440/8
2016-02-11T00:37:20ZRefined MDP-based branch-and-fix algorithm for the Hamiltonian cycle problem
http://hdl.handle.net/2440/86243
Title: Refined MDP-based branch-and-fix algorithm for the Hamiltonian cycle problem
Author: Ejov, V.; Filar, J.A.; Haythorpe, M.; Nguyen, G.T.
Abstract: We consider the famous Hamiltonian cycle problem (HCP) embedded in a Markov decision process (MDP). More specifically, we consider the HCP as an optimisation problem over the space of occupation measures induced by the MDP's stationary policies. In recent years, this approach to the HCP has led to a number of alternative formulations and algorithmic approaches. In this paper, we focus on a specific embedding, because of the work of Feinberg. We present a “branch-and-fix” type algorithm that solves the HCP. At each branch of the algorithm, only a linear program needs to be solved and the dimensions of the successive linear programs are shrinking rather than expanding. Because the nodes of the branch-and-fix tree correspond to specially structured 1-randomised policies, we characterise the latter. This characterisation indicates that the total number of such policies is significantly smaller than the subset of all 1-randomised policies. Finally, we present some numerical results.2009-01-01T00:00:00ZA coupled damage-plasticity model for concrete based on thermodynamic principles: Part II: non-local regularization and numerical implementation
http://hdl.handle.net/2440/85371
Title: A coupled damage-plasticity model for concrete based on thermodynamic principles: Part II: non-local regularization and numerical implementation
Author: Nguyen, G.; Houlsby, G.2008-01-01T00:00:00ZA coupled damage-plasticity model for concrete based on thermodynamic principles: Part 1: model formulation and parameter identification
http://hdl.handle.net/2440/85370
Title: A coupled damage-plasticity model for concrete based on thermodynamic principles: Part 1: model formulation and parameter identification
Author: Nguyen, G.; Houlsby, G.2008-01-01T00:00:00ZDevelopment of an approach to constitutive modelling of concrete: isotropic damage coupled with plasticity
http://hdl.handle.net/2440/85359
Title: Development of an approach to constitutive modelling of concrete: isotropic damage coupled with plasticity
Author: Nguyen, G.; Korsunsky, A.2008-01-01T00:00:00Z