Final Project Report: Plan for a Model PIMS

Development of the performance information and management systems (PIMS) to monitor labor market outcomes of program participants, and guide program management of active labor market programs (ALMPs)

Segmentation of Natural Images Using Scale-Space Representations: A Linear and a Non-Linear Approach

In general purpose computer vision systems, unsupervised image analysis is mandatory in order to achieve an automatic operation. In this paper a different approach to image segmentation for natural scenes is presented. Scale-Space representation is used to extract the structure from meaningful objects in the image. Two different scale-spaces are analysed in the paper. On one hand Isotropic Diffusion (linear scale-space) is presented as the basis for an uncommitted front end, not relying on any special feature of the image. On the other hand the Total Variation Diffusion (non-linear scale-space) which makes a special emphasis on edges is also analysed. A hierarchical decomposition of the image is performed on the basis of the special characteristics of each scale-space. Iso-intensity paths will be tracked in the case of linear scale-space, whereas in the case of non-linear scale-space the evolution of level sets through scale will be tracked. In the framework of linear scale-space, the use of additional information to improve the robustness in the structure extraction is introduced. Appart from the set of several diffused versions of the image, a representation of edges through scale is included to supervise the generation of the hierarchical tree that represents the image

Massive binaries and the enrichment of the interstellar medium in globular clusters

Abundance anomalies observed in globular cluster stars indicate pollution with material processed by hydrogen burning. Two main sources have been suggested: asymptotic giant branch stars and massive stars rotating near the break-up limit. We discuss the potential of massive binaries as an interesting alternative source of processed material. We discuss observational evidence for mass shedding from interacting binaries. In contrast to the fast, radiatively driven winds of massive stars, this material is typically ejected with low velocity. We expect that it remains inside the potential well of a globular cluster and becomes available for the formation or pollution of a second generation of stars. We estimate that the amount of processed low-velocity material that can be ejected by massive binaries is larger than the contribution of two previously suggested sources combined.Comment: 6 pages, 2 figures, to appear in the proceedings of IAU Symposium 266, "Star Clusters - Basic Galactic Building Blocks throughout Time and Space", 10-14 August 2009, at the general assembly in Rio de Janeiro, Brazi

Multiresolution Segmentation of Natural Images: From linear to Non-Linear Scale-Space Representations

In this paper, we introduce a framework that merges classical ideas borrowed from scale-space and multi-resolution segmentation with non-linear partial differential equations. A non-linear scale-space stack is constructed by means of an appropriate diffusion equation. This stack is analyzed and a tree of coherent segments is constructed based on relationships between different scale layers. Pruning this tree proves to be a very efficient tool for unsupervised segmentation of different classes of images (e.g. natural, medical ...). This technique is light on the computational point of view and can be extended to non-scalar data in a straightforward manner

Unusual giant magnetostriction in the ferrimagnet Gd2/3_{2/3}Ca1/3_{1/3}MnO3_3

We report an unusual giant linear magnetostrictive effect in the ferrimagnet Gd$_{2/3}$Ca$_{1/3}$MnO$_3$ ($T_{c} \approx$80 K). Remarkably, the magnetostriction, negative at high temperature ($T \approx T_{c}$), becomes positive below 15 K when the magnetization of the Gd sublattice overcomes the magnetization of the Mn sublattice. A rather simple model where the magnetic energy competes against the elastic energy gives a good account of the observed results and confirms that Gd plays a crucial role in this unusual observation. Unlike previous works in manganites where only striction associated with 3$d$ Mn orbitals is considered, our results show that the lanthanide 4$f$ orbitals related striction can be very important too and it cannot be disregarded.Comment: 6 pages, 3 figure