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Now showing items 11-20 of 65
Plan-view Trajectory Estimation with Dense Stereo Background Models
(2001-02-01)
In a known environment, objects may be tracked in multiple views using a set of back-ground models. Stereo-based models can be illumination-invariant, but often have undefined values which inevitably lead to foreground ...
Exploration in Gradient-Based Reinforcement Learning
(2001-04-03)
Gradient-based policy search is an alternative to value-function-based methods for reinforcement learning in non-Markovian domains. One apparent drawback of policy search is its requirement that all actions be 'on-policy'; ...
Strong embedded discontinuities for simulating fracture in quasi-brittle materials
(Fracture Mechanics of Concrete StructuresFracture Mechanics of Concrete Structures, 2001)
In this paper embedded strong discontinuities are used to model discrete cracking in materials like concrete. In the approach followed a discontinuous displacement field is considered and the deformation is localized at a ...
Time scale in concrete fracture: a model based on partitions of unity
(Proceedings of the 4th International Conference on Fracture Mechanics of Concrete Structures (FRAMCOS4)Proceedings of the 4th International Conference on Fracture Mechanics of Concrete Structures (FRAMCOS4), 2001)
Intense research efforts have been put in the formulation of theories for crack initiation and propagation in concrete. Yet, little attention has been paid to the time-dependence of fracture, despite evidence of its ...
A p-adaptive scheme for overcoming volumetric locking during isochoric plastic deformation
(Solids, Structures and Coupled Problems in Engineering : ECCM-2001: 2nd European Conference on Computational MechanicsSolids, Structures and Coupled Problems in Engineering : ECCM-2001: 2nd European Conference on Computational Mechanics, 2001)
A p-adaptive scheme is developed in order to overcome volumetric locking in low order finite elements. A special adaptive scheme is used which is based on the partition of unity concept. This allows higher order polynomial ...
Multi-level analysis of localisation problems
(2001)
Localisation processes, such as shear banding and necking, have been investigated following a macroscopic and a microscopic approach. Both approaches have been formulated within a finite deformation plasticity framework. ...
Computational modelling of cracks in viscoplastic media
(Proceedings of the 10th International Conference on FractureProceedings of the 10th International Conference on Fracture, 2001)
A newly developed numerical model is used to simulate propagating cracks in a strain softening viscoplastic medium. The model allows the simulation of displacement discontinuities independently of a finite element mesh. ...
Importance Sampling for Reinforcement Learning with Multiple Objectives
(2001-08-01)
This thesis considers three complications that arise from applying reinforcement learning to a real-world application. In the process of using reinforcement learning to build an adaptive electronic market-maker, we find ...
An Algorithm for Bootstrapping Communications
(2001-08-13)
I present an algorithm which allows two agents to generate a simple language based only on observations of a shared environment. Vocabulary and roles for the language are learned in linear time. Communication is robust and ...
Reducing Drift in Parametric Motion Tracking
(2001-05-07)
We develop a class of differential motion trackers that automatically stabilize when in finite domains. Most differ-ential trackers compute motion only relative to one previous frame, accumulating errors indefinitely. We ...