86,898 research outputs found
Upper Bounds for the Euclidean Operator Radius and Applications
No full textThe main aim of the present paper is to establish various sharp
upper bounds for the Euclidean operator radius of an n−tuple of bounded
linear operators on a Hilbert space. The tools used are provided by several
generalisations of Bessel inequality due to Boas-Bellman, Bombieri and the
author. Natural applications for the norm and the numerical radius of bounded
linear operators on Hilbert spaces are also given
Upper Bounds for the Distance to Finite-Dimensional Subspaces in Inner Product Spaces
No full textWe establish upper bounds for the distance to finite-dimensional
subspaces in inner product spaces and improve some generalisations of Bessel’s
inequality obtained by Boas, Bellman and Bombieri. Refinements of the
Hadamard inequality for Gram determinants are also given
When Does the Bombieri–Vinogradov Theorem Hold for a Given Multiplicative Function?
No full textLet f and g be 1-bounded multiplicative functions for which f ∗ g = 1.=1.
The Bombieri-Vinogradov Theorem holds for both f and g if and only if the Siegel-Walfisz
criterion holds for both f and g, and the Bombieri-Vinogradov Theorem holds for f restricted
to the primes
Configuring Graph Traversal Applications for GPUs: Analysis of Implementation Strategies and their Correlation with Graph Characteristics
No full textImplementing a graph traversal (GT) algorithm for GPUs is a very challenging task. It is a core primitive for many graph analysis applications and its efficiency strongly impacts on the overall application performance. Different strategies have been proposed to implement the GT algorithm by exploiting the GPU characteristics. Nevertheless, the efficiency of each of them strongly depends on the graph characteristics. This paper presents an analysis of the most important features of the parallel GT algorithm, which include frontier queue management, load balancing, duplicate removing, and synchronization during graph traversal iterations. It shows different techniques to implement each of such features for GPUs and the comparison of their performance when applied on a very large and heterogeneous set of graphs. The results allow identifying, for each feature and among different implementation techniques of them, the best configuration to address the graph characteristics. The paper finally presents how such a configuration analysis and set allow traversing graphs with throughput up to 14,000 MTEPS on single GPU devices, with speedups ranging from 1.2x to 18.5x with regard to the best parallel applications for GT on GPUs at the state of the art
The Bombieri-Pila determinant method
No full textIn this expository note, we give a concise and accessible introduction to the
real-analytic determinant method for counting integral points on algebraic
curves, based on the classic 1989 paper of Bombieri-Pila.Comment: 17 pages. arXiv admin note: expository pape
Efficient load balancing techniques for graph traversal applications on GPUs
No full textEfficiently implementing a load balancing technique in graph traversal applications for GPUs is a critical task. It is a key feature of GPU applications as it can sensibly impact on the overall application performance. Different strategies have been proposed to deal with such an issue. Nevertheless, the efficiency of each of them strongly depends on the graph characteristics and no one is the best solution for any graph. This paper presents three different balancing techniques and how they have been implemented to fully exploit the GPU architecture. It also proposes a set of support strategies that can be modularly applied to the main balancing techniques to better address the graph characteristics. The paper presents an analysis and a comparison of the three techniques and support strategies with the best solutions at the state of the art over a large dataset of representative graphs. The analysis allows statically identifying, given graph characteristics and for each of the proposed techniques, the best combination of supports, and that such a solution is more efficient than the techniques at the state of the art
On the Automatic Generation of GPU‐oriented Software Applications from RTL IPs
No full textGraphics processing units (GPUs) have been explored as a new computing paradigm for accelerating computation intensive applications. In particular, the combination between GPUs and CPU has proved to be an effective solution for accelerating the software execution, by mixing the few CPU cores optimized for serial processing with many smaller GPU cores designed for massively parallel computations. In addition, sustained by the need of low power consumption besides high performance, a recent trend is combining GPUs and CPU onto a single die (e.g., AMD Fusion, Intel Sandy Bridge, NVIDIA Tegra). The good tradeoff between computing capability and power consumption makes the integrated GPUs a promising alternative for accelerating a wide range of software application for embedded systems. Nevertheless, algorithms must be redesigned to take advantage of these architectures and such a manual parallelization often results in being unsatisfactory. This paper presents a methodology to automatically generate software applications for GPUs, by reusing existing and preverifiedregister-transfer level (RTL) intellectual-properties (IPs). The methodology aims at exploiting the intrinsic parallelism of RTL IPs (such as process concurrency and pipeline micro-architecture) for generating the parallel software implementation of the functionality. The experimental resultsshow how the performance obtained by running the RTL functionality as software applications on GPUs outperform those provided by the RTL code mapped into a hardware accelerator
Leverage mechanical alterations during walking at self-selected speed in patients with Parkinson's disease
No full textIndividuals with Parkinson's disease (PD) show poor walking performance compared to healthy adults. Leverage changes may provide insight into this walking abnormality, since they have important effects on both biomechanical and physiological variables. Hence, we investigated the differences in internal and external moment arms at the knee and ankle joints, as well as the effective mechanical advantage during walking at self-selected speed. Furthermore, the effects on walking of a simultaneous cognitive task were analysed. Kinetic (resultant ground reaction force and joint moments), kinematic (movement speed) and mechanical leverage (internal and external moment arms) parameters of 10 mild-to-moderate PD patients and 10 age-matched controls were measured in single and dual task condition. Finally, effective mechanical advantage was calculated as the ratio between internal and external moment arm for each joint. PD patients had a slower walking and showed larger and lower values of knee and ankle joint moments, respectively. No difference in force among groups was recorded. External moment arms were larger (in both joints) for PD, whereas slight changes were observed for internal moment arms. Consequently, effective mechanical advantage values seemed to be lower for PD. Surprisingly, leverage difference among groups was reduced during the dual task condition, resulting in a "more effective" walking strategy for PD. These findings suggest that during single task PD patients have several leverage disadvantages, which could affect the joint assessment. On the contrary, during dual task they reduced these mechanical negative effects by positively obtaining normal values of effective mechanical advantage
Cistic Fibrosis mutation testing in Italy.
No full textIn Italy, Cystic fibrosis (CF) mutation frequency differences have been observed in different regions. In the northeastern Veneto and Trentino Alto Adige regions, a complete cystic fibrosis transmembrane conductance regulator (CFTR) gene screening in CF patients detected through a newborn screening program has identified about 90% of the mutations. In these two regions, the current detection rate using a CF screening panel containing the 16 most common mutations is 86.6%. CF mutations in some other Italian regions have not been so thoroughly analysed. Available data indicate that a more general national screening panel comprising 31 mutations may detect about 75 % of all CF mutations in Italy
Crystal and molecular structures of h3-propenyl and h3-2-methyl propenyl-bis(triphenylphosphine) platinum (II) perchlorates
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