Achieving Optimal Inter-Node Communication in Graph Partitioning Using Random Selection and Breadth-First Search

Processing large graph datasets represents an increasingly important area in computing research and applications. The size of many graph datasets has increased well beyond the processing capacity of a single computing node, thereby necessitating distributed approaches. As these datasets are processed over a distributed system of nodes, this leads to an inter-node communication cost problem that negatively affects system performance. Previously proposed algorithms implemented breadth-first search (BFS) for graph searching and focused on the execution, parallel performance and not the communication. In this paper a new methodology is proposed that combines BFS with random selection in order to partition large graph datasets and effectively minimize inter-node communication. The new method is discussed and applied to the single-source shortest path and PageRank algorithms using three graphs that are representative of real-world scenarios. Experimental results show that graph inter-node communication for canonical graphs representative of real-world data is improved up to 42 % in case of Powerlaw graph, up to 27 % in case of Random near K-regular graph (with low degree), and up to 7 % in case of Random near K-regular graph (with high degree).     

Contour-based focus of attention mechanism to speed up object detection and labeling in 3D scenes

In this paper, a contour-based focus of attention approach is presented. Fast to compute, contour based features are extracted from 3D scenes and matched to model parts of objects. Local reference frames associated with the features induce a translation and rotation, resulting in a vote being cast for the presence of the object in a certain position within the scene. In these positions, HoG features are extracted and SVM classification is applied. Detection results and computation times are compared to those corresponding to a sliding window approach.     

Image and Fourier Transform Formation by GRIN Lenses: Pupil Effect

Abstract

A detailed study of image and Fourier transform formation by GRIN lenses is presented. It is shown how, within paraxial approximation, GRIN lenses exhibit similar behaviour to those of conventional lenses.     

Usability perception of different video game devices in elderly users

The purpose of this study was to evaluate the usability perception of seniors on video game use with different control devices. Twenty-four seniors participated in the study (12 women, 12 men, 69 years old in average) and eight children (8 years old in average). The setting included the use of two Kinect motion sensors, three computers, three projectors, three video cameras, two audio devices, the Angry Birds and Happy Sky videogames, one Xbox 360 console, a Nintendo Wii device and a Touchscreen configured so that participants could play the games in senior–child pairs. Data were collected according to user friendliness, experience and social interaction. This study suggests that video game control devices for seniors should be adapted to compensate for their function, sensor and cognitive limitations.     

Comparative study of the morphological degradation in nickel thin films exposed to H<Subscript>2</Subscript>S media and deposited by magnetron sputtering and electrolytic process

Nickel thin films with regular configuration and similar thickness were deposited on steel AISI 1018 (UNSG 10180) by two different techniques: magnetron sputtering and electrolytic process. The main aim of this work is to compare the surfaces deposited films made by the two techniques using the scanning electronic microscopy and to identify their morphological differences and imperfections. We evaluate the protective coatings properties when the films are in contact with an acid medium. We also study the thin films coatings by the spectroscopy impedance technique. We obtain that the sputtering deposits present a homogeneous thin film coating that is better than the one obtained by the electrolytic technique. It is expected that the thin film coatings made in this work can protect the steel against corrosion when it is in contact with an acid environment.     

Interconnection and damping assignment passivity-based control of mechanical systems with underactuation degree one

Interconnection and damping assignment passivity-based control is a new controller design methodology developed for (asymptotic) stabilization of nonlinear systems that does not rely on, sometimes unnatural and technique-driven, linearization or decoupling procedures but instead endows the closed-loop system with a Hamiltonian structure with a desired energy function-that qualifies as Lyapunov function for the desired equilibrium. The assignable energy functions are characterized by a set of partial differential equations that must be solved to determine the control law. We prove in this paper that for a class of mechanical systems with underactuation degree one the partial differential equations can be explicitly solved. Furthermore, we introduce a suitable parametrization of assignable energy functions that provides the designer with a handle to address transient performance and robustness issues. Finally, we develop a speed estimator that allows the implementation of position-feedback controllers. The new result is applied to obtain an (almost) globally stabilizing scheme for the vertical takeoff and landing aircraft with strong input coupling, and a controller for the pendulum in a cart that can swing-up the pendulum from any position in the upper half plane and stop the cart at any desired location. In both cases we obtain very simple and intuitive position-feedback solutions.     

Dynamic event trees in accident sequence analysis: application to steam generator tube rupture

A dynamic event tree method for analyzing the risk associated with dynamic nuclear power plant accident sequences is presented. The method provides a framework for treating stochastic variations in operating crew states (defined by substrates characterizing the accident diagnosis, the planned actions, and the crew quality) as well as stochastic variations in hardware states. Plant process variables are treated deterministically; they are used when determining the likelihood of stochastic branchings. The method is used in an analysis of a steam generator tube rupture (SGTR) accident; it is shown that a number of important operator behavior patterns can be reasonably represented, and that, comparing with conventional event trees, sources of dependencies between failure events can be better defined.     

Hemorrhagic and edema-forming activity and histologic changes in the mouse footpad induced by venoms from Argentinian Bothrops and Crotalus genuses

Hemorrhagic, oedema-forming activities and histopathological alterations in the mouse footpad induced by Bothrops and Crotalus snake venoms from Argentina. Hemorrhagic and oedema-forming activities of various Bothrops and Crotalus snake venoms from Argentina were studied, together with histological alterations in the mouse footpad. The highest oedema-forming activity was found in the venom of B. jararaca, followed by B. jararacussu, B. neuwiedii diporus, B. alternatus, and Crotalus durissus terrificus. Regarding hemorrhage, the highest activity was found in the venom of B. neuwiedii diporus, followed by B. jararacussu, B. alternatus, and B. jararaca. No hemorrhage was observed after injection of Crotalus durissus terrificus venom, in agreement with histological observations of injected footpads. Histological analysis revealed a conspicuous inflammatory reaction in the injected footpad, characterized by oedema and an inflammatory infiltrate rich in polymorphonuclear leucocytes. Necrotic blood vessels and dilated lymphatic vessels were observed after injection of B. jararaca and B. jararacussu venoms, and myonecrosis was evident in tissue of mice injected with B. alternatus and B. neuwiedii diporus.     

Awakening of intensive care patients after prolonged continuous sedation

OBJECTIVE: To investigate the relevance of the Symptom Checklist 90-R Obsessive-Compulsive subscale to cognition in individuals with brain tumor. DESIGN: A prospective study of patients assessed with a neuropsychological test battery. SETTING: A university medical center. PATIENTS: Nineteen adults with biopsy-confirmed diagnoses of malignant brain tumors were assessed prior to aggressive chemotherapy. MAIN OUTCOME MEASURES: Included in the assessment were the Mattis Dementia Rating Scale, California Verbal Learning Test, Trail Making Test B, Symptom Checklist 90-R, Mood Assessment Scale, Beck Anxiety Inventory, and Chronic Illness Problem Inventory. RESULTS: The SCL 90-R Obsessive-Compulsive subscale was not related to objective measures of attention, verbal memory, or age. It was related significantly to symptoms of depression (r = .81, P < .005), anxiety (r = .66, P < .005), and subjective complaints of memory problems (r = .75, P < .005). Multivariate analyses indicated that reported symptoms of depression contributed 66% of the variance in predicting SCL 90-R Obsessive-Compulsive Scores, whereas symptoms of anxiety contributed an additional 6% (P < .0001). CONCLUSIONS: Our data suggest that the SCL 90-R is best viewed as an indicator of unidimensional emotional distress and somatic effects of structural brain injury.