Search results for "SPEED"
showing 10 items of 876 documents
Design Space Exploration of Parallel Embedded Architectures for Native Clifford Algebra Operations
2012
In the past few decades, Geometric or Clifford algebra (CA) has received a growing attention in many research fields, such as robotics, machine vision and computer graphics, as a natural and intuitive way to model geometric objects and their transformations. At the same time, the high dimensionality of Clifford algebra and its computational complexity demand specialized hardware architectures for the direct support of Clifford data types and operators. This paper presents the design space exploration of parallel embedded architectures for native execution of four-dimensional (4D) and five-dimensional (5D) Clifford algebra operations. The design space exploration has been described along wit…
The role of working memory on writing processes.
2021
Literature has extensively demonstrated the coordination role of working memory (WM) in complex tasks such as writing. However, previous studies mostly concentrated on the relation between passive WM (e.g., WM span) components and specific writing tasks (e.g., dictation). Here, we aimed to investigate the relationship between different writing skills and the performance on a WM updating task measuring the more active components of WM. From a pool of 160 Italian pupils (grades 3–5), we selected 46 children divided in two groups based on their WM updating performance. The first group consisted of 21 children with low WM updating performance (≤10th percentile), the second group consisted of 25…
Naming speed and Effortful and Automatic Inhibition in Children with Arithmetic Learning Disabilities
2009
Abstract We report a two-year longitudinal study aimed at investigating the rate of access to numerical and non-numerical information in long-term memory and the functioning of automatic and effortful cognitive inhibition processes in children with arithmetical learning disabilities (ALDs). Twelve children with ALDs, of age 9.3 years, and twelve gender–age-matched controls were involved in the study. Rate of access was measured through digit- and letter-naming tasks, automatic cognitive inhibition was measured using a negative priming paradigm, and effortful cognitive inhibition was measured rating intrusion errors in a working memory task. Children with ALDs suffered from a deficit in the …
Naming speed, automatic inhibition and effortful inhibition in a working memory task in children with arithmetic learning difficulties.
2008
We report a study aimed at investigating rate of access to numerical and non-numerical information in long-term memory and functioning of automatic and effortful cognitive inhibition processes in children with Arithmetical Learning Disabilities (ALD). A group of children with ALD, of age 10,3 years, and a group of gender-age-matched controls were involved in the study. Rate of access was measured through digit- and letter- naming tasks, automatic cognitive inhibition was measured using a negative priming paradigm, and effortful cognitive inhibition was measured rating intrusion errors in the well known Daneman and Carpenter’s (1980) working memory task. No evidence for dysfunction of the au…
Hydrodynamic Analysis of Floating Docks With Alternative Geometries for Floating Wind Turbine Installation
2021
Abstract Installation of spar floating wind turbine offshore is a challenging task. Usually, the spar platform is upended first, and mating of the tower assembly with the spar platform is assisted by a crane vessel. Due to motions of the spar platforms and of the crane vessel, such an operation often takes place in shielded areas with relatively small wave heights and wind speed. The floating dock concept has been recently proposed to expand the weather window for installing spar floating wind turbines. The idea is to use a cylindrical dock to shield the spar platform from wave excitations. However, because of the trapped internal fluid, the cylindrical geometry is subjected to piston mode …
3D simulations of microquasar jets in clumpy stellar winds
2011
High-mass microquasars consist of a massive star and a compact object, the latter producing jets that will interact with the stellar wind. The evolution of the jets, and ultimately their radiative outcome, could depend strongly on the inhomogeneity of the wind, which calls for a detailed study. The hydrodynamics of the interaction between a jet and a clumpy wind is studied, focusing on the global wind and single clump-jet interplay. We have performed, using the code \textit{Ratpenat}, three-dimensional numerical simulations of a clumpy wind interacting with a mildly relativistic jet, and of individual clumps penetrating into a jet. For typical wind and jet velocities, filling factors of abo…
Examination of the shock wave regular reflexion phenomenon in a rarefied supersonic plasma flow
2005
The flow properties of a low-pressure weakly ionized supersonic argon plasma jet are examined using Fabry–Perot interferometry and laser induced fluorescence spectroscopy. The flow velocity and equilibrium temperature measured at the torch nozzle exit are in close agreement with computational fluid dynamics calculations. The model also predicts the plasma flow to be in a rarefied regime. Departure from thermal equilibrium is indeed observed behind the nozzle where the parallel temperature differs significantly from the perpendicular temperature. The development of the axial velocity component along the jet center stream line reveals the occurrence of the shock wave regular reflexion phenome…
The Mach cone signal and energy deposition scenarios in linearized hydrodynamics
2010
Particle correlation measurements associated with a hard or semi-hard trigger in heavy-ion collisions may reflect Mach cone shockwaves excited in the bulk medium by partonic energy loss. This is of great interest because, when compared with theory, such measurements can provide information on the transport properties of the medium. Specifically, the formation of Mach cone shockwaves is sensitive to the viscosity and speed of sound, as well as the detailed nature of the jet medium interaction. However, modeling the physics of shockwave excitation to obtain a meaningful comparison with the measured correlations is very challenging since the correlations arise from an interplay of perturbative…
Metastable oxygen atom velocity and temperature in supersonic CO2plasma expansions
2008
Radial and axial velocity distribution functions of metastable oxygen atoms were obtained by way of resonant laser induced fluorescence spectroscopy at 777.19 nm in rarefied supersonic plasma jets produced from pure CO2 and CO2–N2 gas mixtures. The N2 seeded fraction is 3% in volume in order to mimic the Martian atmosphere composition. The measured lineshapes allow computation of the mean radial velocity and the perpendicular temperature, with respect to the jet axis, as well as the mean axial velocity and the parallel temperature. With an arcjet plasma source input power of 6.5 kW, the metastable O(5S) atom axial velocity is around 4500 m s−1 and the atom perpendicular temperature reaches …
Optimisation des requêtes de similarité dans les espaces métriques répondant aux besoins des usagers
2012
The complexity of data stored in large databases has increased at very fast paces. Hence, operations more elaborated than traditional queries are essential in order to extract all required information from the database. Therefore, the interest of the database community in similarity search has increased significantly. Two of the well-known types of similarity search are the Range (Rq) and the k-Nearest Neighbor (kNNq) queries, which, as any of the traditional ones, can be sped up by indexing structures of the Database Management System (DBMS). Another way of speeding up queries is to perform query optimization. In this process, metrics about data are collected and employed to adjust the par…