Integrodifferential equations for multiscale wavelet shrinkage : the discrete case

We investigate the relations between wavelet shrinkage and integrodifferential equations for image simplification and denoising in the discrete case. Previous investigations in the continuous one-dimensional setting are transferred to the discrete multidimentional case. The key observation is that a wavelet transform can be understood as derivative operator in connection with convolution with a smoothing kernel. In this paper, we extend these ideas to the practically relevant discrete formulation with both orthogonal and biorthogonal wavelets. In the discrete setting, the behaviour of the smoothing kernels for different scales is more complicated than in the continuous setting and of special interest for the understanding of the filters. With the help of tensor product wavelets and special shrinkage rules, the approach is extended to more than one spatial dimension. The results of wavelet shrinkage and related integrodifferential equations are compared in terms of quality by numerical experiments

The continuous shearlet transform in arbitrary dimensions

This paper is concerned with the generalization of the continuous shearlet transform to higher dimensions. Similar to the two-dimensional case, our approach is based on translations, anisotropic dilations and specific shear matrices. We show that the associated integral transform again originates from a square-integrable representation of a specific group, the full n-variate shearlet group. Moreover, we verify that by applying the coorbit theory, canonical scales of smoothness spaces and associated Banach frames can be derived. We also indicate how our transform can be used to characterize singularities in signals

Combines l2 data and gradient fitting in conjunction with l1 regularization

We are interested in minimizing functionals with l2 data and gradient fitting term and (absolute) l1 regularization term with higher order derivatives in a discrete setting. We examine the structure of the solution in 1d by reformulating the original problem into a contact problem which can be solved by dual optimization techniques. The solution turns out to be a discrete polynomial spline whose knots coincide with the contact points. In 2d we modify Chambolle's algorithm to solve the minimization problem with absolute l1 norm and second order derivatives. This requires the application of fast cosine transforms. We demonstrate by numerical denoising examples that the l2 gradient fitting term can be used to avoid both edge blurring and staircasing effects

Analyzing Conflict Freedom For Multi-threaded Programs With Time Annotations

Avoiding access conflicts is a major challenge in the design of multi-threaded programs. In the context of real-time systems, the absence of conflicts can be guaranteed by ensuring that no two potentially conflicting accesses are ever scheduled concurrently.In this paper, we analyze programs that carry time annotations specifying the time for executing each statement. We propose a technique for verifying that a multi-threaded program with time annotations is free of access conflicts. In particular, we generate constraints that reflect the possible schedules for executing the program and the required properties. We then invoke an SMT solver in order to verify that no execution gives rise to concurrent conflicting accesses. Otherwise, we obtain a trace that exhibits the access conflict.Comment: http://journal.ub.tu-berlin.de/eceasst/article/view/97

Dança como cena-grafia do saber

O presente artigo discute o lugar da dança contemporânea nocampo dos saberes humanos. Esboça a relação entre dança e escrita enquanto tentativa de fixar o momento efêmero da dança e oferecê-lo enquanto conhecimento objetivado. Contra essa tentativa, o ensaio mostra como a dança contemporânea coloca seus saberes enquanto gestos de desdefinições em relação aos campos fixos dos saberes humanos. Propõe o saber da dança como um espaço de experiências e vivências cujo objetivo é colocar em xeque tanto uma lógica estável daslinguagens cênicas quanto uma posição fixa do observador, para tornar perceptíveis os parâmetros de orientação inscritos em uma situação cultural e cênica. Os saberes da dança revelam, assim, sua afinidade com outras mudanças paradigmáticas no campo dos saberes científicos

Integrodifferential equations for multiscale wavelet shrinkage : the discrete case

We investigate the relations between wavelet shrinkage and integrodifferential equations for image simplification and denoising in the discrete case. Previous investigations in the continuous one-dimensional setting are transferred to the discrete multidimentional case. The key observation is that a wavelet transform can be understood as derivative operator in connection with convolution with a smoothing kernel. In this paper, we extend these ideas to the practically relevant discrete formulation with both orthogonal and biorthogonal wavelets. In the discrete setting, the behaviour of the smoothing kernels for different scales is more complicated than in the continuous setting and of special interest for the understanding of the filters. With the help of tensor product wavelets and special shrinkage rules, the approach is extended to more than one spatial dimension. The results of wavelet shrinkage and related integrodifferential equations are compared in terms of quality by numerical experiments