Relevant bibliographies by topics / Edge velocity

Academic literature on the topic 'Edge velocity'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Contents

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Edge velocity.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Edge velocity"

1

Anagaw, Amsalu Y., and Mauricio D. Sacchi. "Edge-preserving smoothing for simultaneous-source full-waveform inversion model updates in high-contrast velocity models." GEOPHYSICS 83, no. 2 (March 1, 2018): A33—A37. http://dx.doi.org/10.1190/geo2017-0563.1.

Full text
Abstract:
Full-waveform inversion (FWI) can provide accurate estimates of subsurface model parameters. In spite of its success, the application of FWI in areas with high-velocity contrast remains a challenging problem. Quadratic regularization methods are often adopted to stabilize inverse problems. Unfortunately, edges and sharp discontinuities are not adequately preserved by quadratic regularization techniques. Throughout the iterative FWI method, an edge-preserving filter, however, can gently incorporate sharpness into velocity models. For every point in the velocity model, edge-preserving smoothing assigns the average value of the most uniform window neighboring the point. Edge-preserving smoothing generates piecewise-homogeneous images with enhanced contrast at boundaries. We adopt a simultaneous-source frequency-domain FWI, based on quasi-Newton optimization, in conjunction with an edge-preserving smoothing filter to retrieve high-contrast velocity models. The edge-preserving smoothing filter gradually removes the artifacts created by simultaneous-source encoding. We also have developed a simple model update to prevent disrupting the convergence of the optimization algorithm. Finally, we perform tests to examine our algorithm.
APA, Harvard, Vancouver, ISO, and other styles
2

Reif, Dylan W., Howard B. Bluestein, Tammy M. Weckwerth, Zachary B. Wienhoff, and Manda B. Chasteen. "Estimating the Maximum Vertical Velocity at the Leading Edge of a Density Current." Journal of the Atmospheric Sciences 77, no. 11 (November 2020): 3683–700. http://dx.doi.org/10.1175/jas-d-20-0028.1.

Full text
Abstract:
AbstractThe maximum upward vertical velocity at the leading edge of a density current is commonly <10 m s−1. Studies of the vertical velocity, however, are relatively few, in part owing to the dearth of high-spatiotemporal-resolution observations. During the Plains Elevated Convection At Night (PECAN) field project, a mobile Doppler lidar measured a maximum vertical velocity of 13 m s−1 at the leading edge of a density current created by a mesoscale convective system during the night of 15 July 2015. Two other vertically pointing instruments recorded 8 m s−1 vertical velocities at the leading edge of the density current on the same night. This study describes the structure of the density current and attempts to estimate the maximum vertical velocity at their leading edges using the following properties: the density current depth, the slope of its head, and its perturbation potential temperature. The method is then be applied to estimate the maximum vertical velocity at the leading edge of density currents using idealized numerical simulations conducted in neutral and stable atmospheres with resting base states and in neutral and stable atmospheres with vertical wind shear. After testing this method on idealized simulations, this method is then used to estimate the vertical velocity at the leading edge of density currents documented in several previous studies. It was found that the maximum vertical velocity can be estimated to within 10%–15% of the observed or simulated maximum vertical velocity and indirectly accounts for parameters including environmental wind shear and static stability.
APA, Harvard, Vancouver, ISO, and other styles
3

Vaivads, A., A. Retinò, Yu V. Khotyaintsev, and M. André. "The Alfvén edge in asymmetric reconnection." Annales Geophysicae 28, no. 6 (June 23, 2010): 1327–31. http://dx.doi.org/10.5194/angeo-28-1327-2010.

Full text
Abstract:
Abstract. We show that in the case of magnetic reconnection where the Alfvén velocity is much higher in the plasma on one side of the current sheet than the other, an Alfvén edge is formed. This edge is located between the electron and ion edges on the high Alfvén velocity side of the current sheet. The Alfvén edge forms because the Alfvén wave generated near the X-line will propagate faster than the accelerated ions forming the ion edge. We discuss possible generation mechanism and the polarization of the Alfvén wave in the case when higher Alfvén speed is due to larger magnetic field and smaller plasma density, as in the case of magnetopause reconnection. The Alfvén wave can be generated due to Hall dynamics near the X-line. The Alfvén wave pulse has a unipolar electric field and the parallel current will be such that the outer current on the high magnetic field side is flowing away from the X-line. Understanding Alfvén edges is important for understanding the separatrix regions at the boundaries of reconnection jets. We present an example of Alfvén edge observed by the Cluster spacecraft at the magnetopause.
APA, Harvard, Vancouver, ISO, and other styles
4

NAYAGAM, VEDHA, and F. A. WILLIAMS. "Lewis-number effects on edge-flame propagation." Journal of Fluid Mechanics 458 (May 10, 2002): 219–28. http://dx.doi.org/10.1017/s0022112002008017.

Full text
Abstract:
Activation-energy asymptotics is employed to explore effects of the Lewis number, the ratio of thermal to fuel diffusivity, in a one-dimensional model of steady motion of edges of reaction sheets. The propagation velocity of the edge is obtained as a function of the relevant Damköhler number, the ratio of the diffusion time to the chemical time. The results show how Lewis numbers different from unity can increase or decrease propagation velocities. Increasing the Lewis number increases the propagation velocity at large Damköhler numbers and decreases it at small Damköhler numbers. Advancing-edge and retreating-edge solutions are shown to exist simultaneously, at the same Damköhler number, if the Lewis number is sufficiently large. This multiplicity of solutions has a bearing on potential edge-flame configurations in non-uniform flows.
APA, Harvard, Vancouver, ISO, and other styles
5

Pitts, R. A. "Ion velocity distributions at the tokamak edge." Physics of Fluids B: Plasma Physics 3, no. 10 (October 1991): 2871–76. http://dx.doi.org/10.1063/1.859919.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

SHAN, H., B. MA, Z. ZHANG, and F. T. M. NIEUWSTADT. "Direct numerical simulation of a puff and a slug in transitional cylindrical pipe flow." Journal of Fluid Mechanics 387 (May 25, 1999): 39–60. http://dx.doi.org/10.1017/s0022112099004681.

Full text
Abstract:
A direct numerical simulation of transitional pipe flow is carried out with the help of a spectral element method and used to investigate the localized regions of ‘turbulent’ flow that are observed in experiments. Two types of such regions can be distinguished: the puff and the slug. The puff, which is generally found at low values of the Reynolds numbers, is simulated for Re = 2200 where the Reynolds number Re is based on the mean velocity UB and pipe diameter D. The slug occurs at a higher Reynolds number and it is simulated for Re = 5000. The computations start with a laminar pipe flow to which is added a prescribed velocity disturbance at a given axial position and for a finite time. The disturbance then evolves further into a puff or slug structure.The simulations confirm the experimentally observed fact that for a puff the velocity near the leading edge changes more gradually than for a slug where an almost discontinuous change is observed. The positions of the leading and trailing edges of the puff and slug are computed from the simulations as a function of time. The propagation velocity of the leading edge is found to be constant and equal to 1.56UB and 1.69UB for the puff and slug, respectively. For the trailing edge the velocity is found to be 0.73UB and 0.52UB, respectively. By rescaling the simulation results obtained at various times to a fixed length, we define an ensemble average. This method is used to compute the average characteristics of the puff and slug such as the spatial distribution of the mean velocity, the turbulent velocity fluctuations and also the wall shear stress. By computing particle trajectories we have investigated the entrainment and detrainment of fluid by a puff and slug. We find that the puff detrains through its trailing edge and entrains through its leading edge. The slug entrains fluid through its leading and through most of its trailing edge. As a consequence the fluid inside the puff is constantly exchanged with fluid outside whereas the fluid inside a slug remains there. These entrainment/detrainment properties which are in agreement with the measurements of Wygnanski & Champagne (1973) imply that the puff has the characteristics of a wave phenomenon while the slug can be characterized more as a material property which travels with the flow.Finally, we have investigated in more detail the velocity field within the puff. In a coordinate system that travels with the mean velocity we find recirculation regions both near the trailing and leading edges which agrees at least qualitatively with experimental data. We also find streamwise vortices, predominantly in the trailing-edge region which have been also observed in experiments and which are believed to play an important role in the dynamics of the transition process.
APA, Harvard, Vancouver, ISO, and other styles
7

Sun, Keke, Ke Yang, Zhaoyu Ku, Yu Liu, and Huajun Dong. "Motion Velocity Detection of Circuit Breaker Operating Mechanism." Journal of Physics: Conference Series 2303, no. 1 (July 1, 2022): 012067. http://dx.doi.org/10.1088/1742-6596/2303/1/012067.

Full text
Abstract:
Abstract The movement speed of the operating mechanism is one of the main factors affecting the breaking performance of the circuit breaker. To accurately detect the movement speed, this paper proposes an image processing method based on LabVIEW virtual instrument and designs a set of software and hardware systems for real-time movement speed detection of the operating mechanism. On the basis of the movement images of the operating mechanism collected by the high-speed camera, it uses the image processing module in LabVIEW to pre-process the images. The paper adopts the Laplacian edge detection operators to detect the edges and extract the edge feature information for straight line fitting and data processing. The experimental results show that the detection system can effectively detect the motion state of the operating mechanism, realize the real-time detection of the motion state of the operating mechanism, and provide technical support for the detection of the motion characteristics of the circuit breaker.
APA, Harvard, Vancouver, ISO, and other styles
8

Глухова, О. Е., А. П. Четвериков, and В. В. Шунаев. "Динамика локализованной кольцевой нелинейной волны в углеродной нанотрубке." Письма в журнал технической физики 47, no. 19 (2021): 15. http://dx.doi.org/10.21883/pjtf.2021.19.51506.18895.

Full text
Abstract:
The propagation of nonlinear localized soliton-like super-acoustic longitudinal waves in a carbon nanotube was explored by the molecular dynamics modeling. Ring waves were excited by pulsed action on all the atoms of the edge zigzag layer and they got an initial velocity along the axis of the nanotube. It was shown that the velocity of a localized (soliton-like) ring super-acoustic wave increased with an increase in the initial velocity of the edge atoms. The calculated dependence of the propagating wave velocity on the initial velocity of the edge atoms was given.
APA, Harvard, Vancouver, ISO, and other styles
9

Wu, Jian, and Rong Di Han. "Experimental Investigation on Chip Deformation in Drilling 1Cr18Ni9Ti." Advanced Materials Research 426 (January 2012): 48–51. http://dx.doi.org/10.4028/www.scientific.net/amr.426.48.

Full text
Abstract:
It is difficult to study the chip deformation due to the complexity of the chip formation process in drilling. The chip deformation has a direct effect on the drilling forces, drilling temperature and surface quality. The austenitic stainless steel 1Cr18Ni9Ti belongs to the hard-to-cut material, so it is necessary to investigate the chip deformation of 1Cr18Ni9Ti in drilling. An experimental investigation of the chip transformation process on the cutting edges using quick-stop of the drilling processes is carried out. Results indicate that the chip deformation increases with the increment of drilling velocity and decreases with the increment of the distance to chisel edge on cutting edge and the feed rate in drilling 1Cr18Ni9Ti; the chip deformation decreases with the increment of drilling velocity, and decreases with the increment of the distance to chisel edge on cutting edge and the feed rate in drilling AISI 1045; the chip deformation in drilling 1Cr18Ni9Ti is larger than that in drilling AISI 1045.
APA, Harvard, Vancouver, ISO, and other styles
10

Glukhova O. E., Chetverikov A. P., and Shunaev V. V. "Dynamics of a localized ring nonlinear wave in a carbon nanotube." Technical Physics Letters 48, no. 13 (2022): 37. http://dx.doi.org/10.21883/tpl.2022.13.53350.18895.

Full text
Abstract:
The propagation of nonlinear localized soliton-like super-acoustic longitudinal waves in a carbon nanotube was explored by the molecular dynamics modeling. Ring waves were excited by pulsed action on all the atoms of the edge zigzag layer and they got an initial velocity along the axis of the nanotube. It was shown that the velocity of a localized (soliton-like) ring super-acoustic wave increased with an increase in the initial velocity of the edge atoms. The calculated dependence of the propagating wave velocity on the initial velocity of the edge atoms was given. Keywords: carbon nanotube, ring nonlinear waves, molecular dynamics.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Edge velocity"

1

Spitz, Nicolas. "Prediction of Trailing Edge Noise from Two-Point Velocity Correlations." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/32637.

Full text
Abstract:
This thesis presents the implementation and validation of a new methodology developed by Glegg et al. (2004) for solving the trailing edge noise problem. This method is based on the premises that the noise produced by a surface can be computed by the integral of the cross product between the velocity and vorticity fields, of the boundary layer and shed vorticity (Howe (1978)). To extract the source terms, proper orthogonal decomposition is applied to the velocity cross spectrum to extract modes of the unsteady velocity and vorticity. The new formulation of the trailing edge noise problem by Glegg et al. (2004) is attractive because it applies to the high frequencies of interest but does not require an excessive computational effort. Also, the nature of the formulation permits the identification of the modes producing the noise and their associated velocity fluctuations as well as the regions of the boundary layer responsible for the noise production. The source terms were obtained using the direct numerical simulation of a turbulent channel flow by Moser et al. (1998). Two-point velocity and vorticity statistics of this data set were obtained by averaging 41 instantaneous fields. For comparisons purposes, experimental boundary layer data by Adrian et al. (2000) was chosen. Statistical reduction of 50 velocity fields obtained by particle image velocimetry was performed and analysis of the two-point correlation function showed features similar to the DNS data case. Also, proper orthogonal decomposition revealed identical dominant modes and eddy structures in the flow, therefore justifying considering the channel flow as an external boundary layer for noise calculations. Comparison of noise predictions with experimental data from Brooks et al. (1989) showed realistic results with the largest discrepancies, on the order of 5 dB, occurring at the lowest frequencies. The DNS results are least applicable at these frequencies, since these correspond to the longest streamwise lengthscales, which are the most affected by the periodicity conditions used in the DNS and also are the least representative of the turbulence in an external boundary layer flow. Most of the noise was shown to be produced by low-frequency streamwise velocity modes in the bottom 10% of the boundary layer and locations closest to the wall. Only 6 modes were required to obtain noise levels within 1 dB of the total noise. Finally, the method for predicting spatial velocity correlation from Reynolds stress data in wake flows, originally developed by Devenport et al. (1999, 2001) and Devenport and Glegg (2001), was adapted to boundary-layer type flows. This method, using Reynolds stresses and the prescription of a lengthscale to extrapolate the full two-point correlation, was shown to produce best results for a lengthscale prescribed as proportional to the turbulent macroscale. Noise predictions using modeled two-point statistics showed good agreement with the DNS inferred data in all but frequency magnitude, a probable consequence of the modeling of the correlation function in the streamwise direction. Other quantities associated to noise were seen to be similar to the ones obtained using the DNS.
Master of Science
APA, Harvard, Vancouver, ISO, and other styles
2

Eisenman, Adam. "Estimating light edge velocity based on retinal ganglion cell spike trains." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40323.

Full text
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 136-137).
This thesis is intended to present a specific sub-problem of a larger one we call the 'Inverse Problem'. We wish to estimate the velocity (speed and direction) of an edge of light which is moving on the photoreceptor layer of a rabbit retinal patch. We make these estimates based solely on the electrical response measured from the retinal ganglion cells (RGCs). We present various algorithms for doing so and present sensitivity analysis of such algorithms. We test the performance of the algorithms on data recorded from retina and on data produced by simulation. We find that we are able to extract enough information about the edge velocity from ON and OFF RGCs when the edge of light is wide. However, our best algorithm's performance decays significantly as the edge of light gets narrower. This leads us to develop algorithms that use ON-OFF directionally selective (DS) cells in conjunction with non-directional ON and OFF cells to produce better estimates of the velocity for narrow edges of light. In addition, we develop a model to simulate the response of a DS cell to 1-dimensional light motion.
by Adam Eisenman.
S.M.
APA, Harvard, Vancouver, ISO, and other styles
3

Malhotra, Anjum. "Low velocity edge impact on composite laminates : damage tolerance and numerical simulations." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8571.

Full text
Abstract:
Composite laminates are increasingly being used in more complex structural applications where edges and cut outs are inevitable. These applications include wing skins of military and civil aircraft, further aerospace applications as well as automotive panels and critical structures. Composite components in such applications are highly susceptible to damage. Composites behave in a different manner to conventional metallic materials, which has introduced several design problems not previously encountered. One such problem has been the susceptibility of the material to accidental low energy impacts which frequently leave no visible mark on the impacted surface but considerable internal damage. Investigation of the residual strength and stiffness of composites after edge impact has become important for the design of aerospace components. Previously, the research work involved central impact of composite laminates but in this research we are investigating edge impact behaviour of composite laminates as parts of composite structures are particularly vulnerable to impacts, including near the edge of an inspection port or other aperture. Furthermore, impacts to such areas may lead to more severe damage near the edge of the laminate rather than the surface. Thus the present work extends these investigations to impact on the edge of composite laminates. The thesis includes both experimental investigations and finite element simulations of impact damage on the plane of the laminate near the edge (near-edge), and on the edge (on-edge) of composite laminates. A comparison with centre impact with on and near-edge impact is done to understand the damage on the edges and away from the edges. A new design has been developed and implemented to perform edge impact experiments. The research investigated the effects of various parameters like thickness, absorbed energies, force-time histories and damage behaviour of composite laminate. The damage size and mechanisms have been explored. Impact simulation was carried out using finite element code Abaqus. Explicit solution technique of the code was used to analyse the edge impact phenomenon. Results of the finite element analysis were compared with experiments. The residual strength of the laminates under compressive and tensile loading has been measured. Tensions after impact (TAI) tests were conducted to evaluate the residual load carrying capacity. The effect of edge impact on the low velocity impact response and the residual tensile strength is discussed via the test results. This thesis also includes computed tomography as the main technique for micro level damage characterisation and investigates the study of damage mechanisms of glass/epoxy laminates subjected to edge impact with varying energy levels and thickness. Computed Tomography aims to provide damage behaviour such as internal damage state, delaminations during different types of edge impact.
APA, Harvard, Vancouver, ISO, and other styles
4

Josefsson, Mattias. "3D camera with built-in velocity measurement." Thesis, Linköpings universitet, Datorseende, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-68632.

Full text
Abstract:
In today's industry 3D cameras are often used to inspect products. The camera produces both a 3D model and an intensity image by capturing a series of profiles of the object using laser triangulation. In many of these setups a physical encoder is attached to, for example, the conveyor belt that the product is travelling on. The encoder is used to get an accurate reading of the speed that the product has when it passes through the laser. Without this, the output image from the camera can be distorted due to a variation in velocity. In this master thesis a method for integrating the functionality of this physical encoder into the software of the camera is proposed. The object is scanned together with a pattern, with the help of this pattern the object can be restored to its original proportions.
I dagens industri används ofta 3D-kameror för att inspektera produkter. Kameran producerar en 3D-modell samt en intensitetsbild genom att sätta ihop en serie av profilbilder av objektet som erhålls genom lasertriangulering. I många av dessa uppställningar används en fysisk encoder som återspeglar hastigheten på till exempel transportbandet som produkten ligger på. Utan den här encodern kan bilden som kameran fångar bli förvrängd på grund av hastighetsvariationer. I det här examensarbetet presenteras en metod för att integrera funktionaliteten av encodern in i kamerans mjukvara. För att göra detta krävs att ett mönster placeras längs med objektet som ska bli skannat. Mönstret återfinns i bilden fångad av kameran och med hjälp av detta mönster kan hastigheten bestämmas och objektets korrekta proportioner återställas.
APA, Harvard, Vancouver, ISO, and other styles
5

Sierchio, Jennifer Marie. "Comparison of edge turbulence velocity analysis techniques using Gas Puff Imaging data on Alcator C-Mod." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91073.

Full text
Abstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Physics, 2014.
30
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 117-119).
In the past, two methods for analyzing data from the Gas Puff Imaging diagnostic on Alcator C-Mod have been used. One uses temporal and spatial Fourier analysis to obtain wavenumber-frequency spectra, from which a phase velocity is computed [1, 2]. The other is based on time-delay cross-correlation of successive images used to track the motion of discrete emission structures [3, 4]. Several Gas-Puff-Imaging experiments were conducted to obtain data taken using the GPI Phantom Camera. The analysis of and results from these data are discussed in [3]. The results showed that the tracking time-delay-estimation technique found poloidal velocity magnitudes in the 0.1-1.4 km/sec range. However, independent examination of these data using the Fourier analysis yielded magnitudes up to a factor of 10 larger for the same data, and sometimes even disagreed with the direction of motion found. To understand the reasons for these discrepancies, we designed and generated synthetic data that mimics the real data. The user inputs the velocities, sizes, intensities, and distributions of the synthetic emission structures. We have used the synthetic data to test each code rigorously for strengths, weaknesses, and weighting. We have found that the Fourier analysis perfectly returns the correct poloidal velocity when there is no radial velocity component present. We have found that the tracking TDE analysis weights low frequency, low wavenumber features most heavily since they are typically the most intense, but systematically returns a smaller velocity than expected due to issues associated with averaging. After adjusting for these issues, the tracking TDE code now returns the correct value of the poloidal and radial velocities to within 10% for synthetic data as long as there is only one velocity present in the synthetic simulation. We applied these corrections to the analysis of the real data, and found that the measurements changed little in most cases. We then examined, in detail, the Fourier-analysis-derived "conditional" spectra for each shot, and determined that the likely causes for the discrepancies are due either to multiple velocities with emission structures moving in opposite directions in the same field of view or to non-zero "dispersion" in which lower-frequency/lower-wavenumber features are moving with one phase velocity and higher-frequency/higher-wavenumber features are moving with a different phase velocity. In a couple of cases, there may be a radial component in the actual images that may affect the poloidal velocity measurement for the Fourier analysis. Accounting for these explanations, we believe that we have resolved the discrepancies in many cases, and can explain it in the others.
by Jennifer Marie Sierchio.
S.M.
APA, Harvard, Vancouver, ISO, and other styles
6

Glenn, Timothy Scott 1971. "Velocity measurement of laser energy induced Rayleigh surface waves on bulk substrates employing the optical beam deflection (knife-edge detection) method." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/49947.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Whitehouse, David Richard Carleton University Dissertation Engineering Aerospace. "The effect of axial velocity ratio, turbulence intensity, incidence and leading edge geometry on the off-design performance of a turbine blade cascade." Ottawa, 1993.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Abraham, Rohit Mathew. "An Experimental Study of Scuffing Performance of a Helical Gear Pair Subjected to Different Lubrication Methods." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397228984.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Leybros, Robin. "Etude des vitesses de dérive fluides dans le plasma de bord des tokamaks : modélisation numérique et comparaison simulation/expérience." Thesis, Ecole centrale de Marseille, 2015. http://www.theses.fr/2015ECDM0006/document.

Full text
Abstract:
Le transport des particules et de la chaleur dans la zone de bord des tokamaks joue un rôle déterminant à la fois sur les performances du plasma confiné et sur l’extraction de la puissance et ainsi la durée de vie des composants face au plasma. C’est dans ce contexte que s’inscrit ce travail de thèse, qui porte sur le rôle joué par les écoulements transverses au champ magnétique dans l’équilibre entre dynamique parallèle et dynamique perpendiculaire qui régit la région périphérique d’un tokamak. Ces écoulements peuvent produire des asymétries poloïdales du dépôt de chaleur et de particules sur les composants face au plasma, et plus généralement des asymétries des diverses quantités dans le plasma. Les vitesses de dérive radiale sont d’origine électrique (liées à la présence d’un champ électrique radial résultant de l’équilibre des charges) ou liées aux effets de la géométrie toroïdale induisant une inhomogénéité du champ magnétique (vitesse de gradient-courbure). Pour progresser dans la compréhension de ces phénomènes, la modélisation numérique du transport et de la turbulence en géométrie complexe est indispensable. En complément, des outils de diagnostic synthétique permettant de modéliser les processus de mesure dans les plasmas numériques sont développés pour permettre une comparaison réaliste entre modèles et expériences. La modélisation des vitesses de dérive perpendiculaire a été introduite dans le code SOLEDGE2D décrivant le transport de la densité, quantité de mouvement et énergie d’un plasma de tokamak. Nous avons d’abord étudié l’impact d’un champ électrique prescrit sur les équilibres plasma, pour comprendre les mécanismes à l’origine des asymétries du plasma et étudier l’établissement d’écoulement parallèle et d’asymétrie du dépôt de chaleur sur les composants face au plasma. Nous avons ensuite implémenté un modèle auto-consistant de résolution du potentiel électrique dans les équations fluides de SOLEDGE2D afin de comprendre l’équilibre du champ électrique et d’étudier l’effet de la configuration magnétique du tokamak et de la vitesse de gradient-courbure sur ce dernier. Dans la deuxième partie de cette thèse, un diagnostic synthétique permettant de modéliser les mesures expérimentales de rétro-diffusion Doppler a été développé et testé en vue d’être appliqué aux simulations du code fluide 3D turbulent, TOKAM3X. Ce diagnostic permet de mesurer la vitesse perpendiculaire du plasma à partir du mouvement des fluctuations de densité. Il a été utilisé ici pour comparer les asymétries de vitesse observées expérimentalement aux asymétries mesurées dans les simulations numériques
The transport of heat and particles in the edge of tokamaks plays a key role in both the performance of the confined plasma and the extraction of power and thus the lifetime of the plasma facing components. It’s in this context that this thesis is inscribed, which focuses on the role played by the transverse magnetic field flows in the balance between parallel and perpendicular dynamic that governs the edge region of a tokamak. These flows can produce poloidal asymmetries of heat and particles deposit on plasma facing components and generally asymmetries of various amounts in plasma. The radial drift velocities are due to the presence of a radial electric field resulting from charge balance (electric drift velocity) or related to effects of the toroidal geometry inducing a magnetic field inhomogeneity (curvature drift velocity). To advance the understanding of these phenomena, numerical modeling of transport and turbulence in complex geometries is essential. In addition, synthetic diagnostic tools for modeling the measurement process in numerical plasmas are developed to enable a realistic comparison between models and experiments. Modeling of perpendicular drift velocities was introduced into the SOLEDGE2D code describing the transport of the density, momentum and energy of a tokamak plasma. We first studied the impact of a prescribed electric field on plasma equilibrium to understand the mechanisms behind plasma asymmetries and study the establishment of parallel flows and asymmetry of the heat flux on plasma facing components. Then we implemented a self-consistent model solving the electric potential in SOLEDGE2D fluid equations to understand the equilibrium of the electric field and to study the effect of the magnetic configuration of the tokamak and the curvature drift velocity on it. In the second part of this thesis, a synthetic diagnosis modeling the experimental measurements of Doppler backscattering was developed and tested in order to be applied to simulations of 3D turbulent fluid code TOKAM3X. This diagnosis measures the perpendicular velocity of the plasma from the movement of the density fluctuations. It was used to compare the perpendicular velocity asymmetries observed experimentally to asymmetries measured in numericalsimulations
APA, Harvard, Vancouver, ISO, and other styles
10

Lismonde, Baudouin. "Champ de vitesse au bord d'attaque et dans le spot laminaire d'un écoulement sur une plaque plane." Grenoble 1, 1987. http://www.theses.fr/1987GRE10074.

Full text
Abstract:
Calcul numerique des champs de vitesse, de pression et de temperature dans la zone pres du bord d'attaque ou il faut utiliser une approximation d'ordre 3 de la couche limite. Mesure des trois composantes de la vitesse de l'ecoulement perturbe par un microjet instantane traversant la couche limite laminaire
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Edge velocity"

1

Yu, S. C. M. Velocity measurements downstream of a lobed forced mixer with different trailing edge configurations. Washington, D. C: American Institute of Aeronautics and Astronautics, 1994.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

The high-velocity edge: How market leaders leverage operational excellence to beat the competition. 2nd ed. New York: McGraw-Hill, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Mueller, T. J. The structure of separated flow regions occurring near the leading edge of airfoils, including transition: Semi-annual status report, February 1986-July 1986. [Washington, D.C: National Aeronautics and Space Administration, 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

The High-Velocity Edge. New York: McGraw-Hill, 2010.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Turbulence measurements on a flap-edge model: Final report : NASA-Ames university consortium, NCC2-5140. [Washington, DC: National Aeronautics and Space Administration, 1996.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

James, VanFossen G., and United States. National Aeronautics and Space Administration., eds. Increased heat transfer to a cylindrical leading edge due to spanwise variations in the freestream velocity. [Washington, D.C.]: National Aeronautics and Space Administration, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

United States. National Aeronautics and Space Administration., ed. The structure of separated flow regions occurring near the leading edge of airfoils, including transition: Semi-annual status report, November 1984 - April 1985. Notre Dame, Ind: Dept. of Aerospace and Mechanical Engineering, University of Notre Dame, 1985.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

K, Takahashi R., Ames Research Center, and United States. Army Aviation Systems Command., eds. NACA 0015 wing pressure and trailing vortex measurements. Washington, D.C: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Numerical studies of boundary-layer receptivity: A progress report. [Washington, DC: National Aeronautics and Space Administration, 1995.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

United States. National Aeronautics and Space Administration., ed. Numerical studies of boundary-layer receptivity: A progress report. [Washington, DC: National Aeronautics and Space Administration, 1995.

Find full text
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "Edge velocity"

1

Gu, J., F. Alamos, D. Schoch, J. Bornhorst, and H. Kim. "The Effects of the High-Velocity Shearing Speed on the Sheared Edge Quality and Edge Cracking." In Forming the Future, 1245–54. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75381-8_103.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Wada, Keiichi, Tetsuo Hasegawa, Yoshiaki Sofue, Yoshiaki Taniguchi, and Asao Habe. "Position-Velocity Diagrams as a Probe of the Bar in Edge-On Galaxies." In Unsolved Problems of the Milky Way, 147–48. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1687-6_19.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Kim, Woo-Joong, and Chan-Hyun Youn. "A Low-Cost Video Analytics System with Velocity Based Configuration Adaptation in Edge Computing." In Transactions on Computational Science and Computational Intelligence, 667–77. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70296-0_48.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Mahesh and K. K. Singh. "Numerical Simulation of GFRP Laminate Under Low-Velocity Impact at Different Edge-Constrained Boundary Conditions." In Lecture Notes on Multidisciplinary Industrial Engineering, 87–95. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9016-6_10.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Jodin, G., J. F. Rouchon, J. Schller, N. Simiriotis, M. Triantafyllou, S. Cazin, P. Elyakime, M. Marchal, and M. Braza. "Electroactive Morphing Vibrating Trailing Edge of a Cambered Wing: PIV, Turbulence Manipulation and Velocity Effects." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 427–39. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-55594-8_35.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Rahul, G. R., V. Jayaram, and S. Bose. "Dependence of Crack Velocity on Stress Intensity Factor in PMMA Using Single-Edge-Notched Clamped Beams." In Advances in Structural Integrity, 205–14. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-7197-3_18.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Kosbi, Klaus, Wieland Weise, Ulla Scheer, Uwe Laun, and Siegfried Boseck. "Measurement of Surface Wave Velocity and Anisotropy at Edges Using Point-Focus Acoustic Microscopy." In Acoustical Imaging, 677–82. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4419-8772-3_110.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

"edge velocity." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 455. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_50506.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Yu, YinQuan. "Optimization of Manufacturing Production and Process." In Smart Manufacturing - When Artificial Intelligence Meets the Internet of Things. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.92304.

Full text
Abstract:
This chapter mainly introduces production processing optimization, especially for machining processing optimization on CNC. The sensor collects the original vibration data in time domain and converts them to the main feature vector using signal processing technologies, such as fast Fourier transform (FFT), short-time Fourier transform (STFT), and wavelet packet in the 5G AI edge computing. Subsequently, the main feature will be sent for cloud computing using genetic programming, Space Vector Machine (SVM), etc. to obtain optimization results. The optimization parameters in this work include machining spindle rotation velocity, cutting speed, and cutting depth, while, the result is the optimized main spindle rotation speed range of CNC, which met machining roughness requirements. Finally, the relationship between vibration velocity and machining quality is further studied to optimize the three operational parameters.
APA, Harvard, Vancouver, ISO, and other styles
10

Lebedev, S. A., A. G. Kostianoy, and S. K. Popov. "Satellite altimetry of the Barents sea." In THE BARENTS SEA SYSTEM, 194–212. Shirshov Institute of Oceanology Publishing House, 2021. http://dx.doi.org/10.29006/978-5-6045110-0-8/(16).

Full text
Abstract:
Satellite altimetry data are used for investigation of the sea level variability and sea ice cover retreat in the Barents Sea in 1992−2018. The data from ERS−1/2, ENVISAT, SARAL/AltiKa, and Sentinel-3A/3B satellites were used in this study. An increasing trend of the sea level of about 2.31 mm/yr was observed in this time period, which caused a total increase in the Barents Sea level by about 6 cm. Linear trends of the sea level change varied from 1.84 mm/yr in July to 4.29 mm/yr in September. The average velocity of the ice edge retreat along the tracks in the northeastern direction is of 10.9 km/yr for the same period. It was found that the ice edge displacement rate tends to increase by 0.30 km/yr per a degree in longitude in the eastward direction. Thus, the ice edge retreat along the “eastern” tracks goes faster than along the “western” ones, which is likely explained by a change in the water dynamics in the Barents Sea.
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Edge velocity"

1

Valenciano, Alejandro A., Morgan Brown, Antoine Guitton, and Mauricio D. Sacchi. "Interval velocity estimation using edge‐preserving regularization." In SEG Technical Program Expanded Abstracts 2004. Society of Exploration Geophysicists, 2004. http://dx.doi.org/10.1190/1.1845232.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Zhao, Peida, Matin Amani, Der-Hsien Lien, Geun Ho Ahn, Daisuke Kiriya, James P. Mastandrea, Joel W. Ager, Eli Yablonovitch, Daryl C. Chrzan, and Ali Javey. "Measuring the edge recombination velocity of monolayer semiconductors." In 2017 Fifth Berkeley Symposium on Energy Efficient Electronic Systems & Steep Transistors Workshop (E3S). IEEE, 2017. http://dx.doi.org/10.1109/e3s.2017.8246197.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Egan, V., D. T. Newport, V. Larcarac, and B. Estebe. "Velocity Field Measurements in Leading Edge Wing Compartments." In ASME 2008 Heat Transfer Summer Conference collocated with the Fluids Engineering, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/ht2008-56321.

Full text
Abstract:
For many applications the optimisation of natural convection cooling is a major design consideration due to factors such as weight, accessibility, cost and power consumption. In aircraft wing compartments, natural convection is the dominant mode of heat transfer due to high wall temperatures resulting from solar loading and heat dissipating internal electronics. This paper investigates the flow structures in a leading edge compartment subject to various thermal boundary conditions. The experimental configuration consisted of two leading edge enclosures; the first is a single compartment while the second has an attached wing box. Particle image velocimetry (PIV) was employed to obtain velocity measurements of the flow in both leading edge enclosures. The second compartment investigated the effect of an adjacent fluid filled enclosure on the flow regime in the leading edge compartment. Higher local velocities were found in the second compartment due to an increase in buoyancy forces resulting from a lower of the average fluid temperature within the compartment. The introduction of a heat dissipating component gave rise to two separate convection structures and in general increased the fluctuations in the both temperature and velocities within the compartment.
APA, Harvard, Vancouver, ISO, and other styles
4

Chang, Young B., Chang H. Cho, and Peter M. Moretti. "Edge Flutter." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0224.

Full text
Abstract:
Abstract During manufacturing processes of thin materials (called webs) such as papers, photographic films, and magnetic films, the free edges of a web can vibrate violently due to the airflow in the cross direction. A traveling-wave analysis was done based on linear potential flow theory, and the critical flow velocity, wave velocity, wavelength and flutter frequency were predicted. Experimental verification was done in a wind tunnel built around a web-translating machine. Two laser-Doppler vibrometers were used for non-contact measurement of wave characteristics. For flexible webs, the theory and test results show good agreement. Test results for stiff webs, however, deviate from the prediction.
APA, Harvard, Vancouver, ISO, and other styles
5

Seo, Haijin, Yuhwa Lee, Yangmo Yoo, Tai-kyong Song, and Jin Ho Chang. "Estimation of sound velocity based on evaluation of edge conspicuity." In 2010 IEEE Ultrasonics Symposium (IUS). IEEE, 2010. http://dx.doi.org/10.1109/ultsym.2010.5935654.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Benson, Michael, Gregory Laskowski, Chris Elkins, and John K. Eaton. "Film-Cooled Trailing Edge Measurements: 3D Velocity and Scalar Field." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-45070.

Full text
Abstract:
Aircraft turbine blade trailing edges commonly are cooled by blowing air through pressure-side cutback slots. The surface effectiveness is governed by the rate of mixing of the coolant with the mainstream, which is typically much faster than predicted by CFD models. 3D velocity and coolant concentration fields were measured in and around a cutback slot using a simple uncambered airfoil with a realistic trailing edge cooling geometry at a Reynolds number of 110,000 based on airfoil chord length, which is lower than practical engines but still in the turbulent regime. The results were obtained using magnetic resonance imaging (MRI) techniques in a water flow apparatus. Magnetic resonance concentration (MRC) scans measured the concentration distribution with a spatial resolution of 0.5 mm3 (compared to a slot height of 5 mm) and an uncertainty near 5%. Magnetic resonance velocimetry (MRV) was used to acquire 3D, three-component mean velocity measurements with a resolution of 1.0 mm3. Coupled concentration and velocity measurements were used to identify flow structures contributing to the rapid mixing, including longitudinal vortices and separation bubbles. Velocity measurements at several locations were compared with an unsteady RANS model. Concentration measurements extrapolated to the surface provided film cooling effectiveness and showed that the longitudinal vortices decreased effectiveness near the lands and reduced the average film cooling effectiveness.
APA, Harvard, Vancouver, ISO, and other styles
7

Anderson, John E., and Carey M. Marcinkovich. "Finding the edge of salt via a dual‐velocity flood." In SEG Technical Program Expanded Abstracts 2005. Society of Exploration Geophysicists, 2005. http://dx.doi.org/10.1190/1.2148094.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Anderson, J. E., and C. M. Marcinkovich. "Finding the Edge of Salt Via a Dual-Velocity Flood." In 68th EAGE Conference and Exhibition incorporating SPE EUROPEC 2006. European Association of Geoscientists & Engineers, 2006. http://dx.doi.org/10.3997/2214-4609.201402013.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Rathore, M. Mazhar, Yaser Jararweh, Muhammad Raheel, and Anand Paul. "Securing High-Velocity Data: Authentication and Key Management Model for Smart City Communication." In 2019 Fourth International Conference on Fog and Mobile Edge Computing (FMEC). IEEE, 2019. http://dx.doi.org/10.1109/fmec.2019.8795312.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Gutkowicz-Krusin, Dina, and Marek Elbaum. "Performance analysis of wind velocity edge techniques utilizing Fabry-Perot etalons." In SPIE's 1995 International Symposium on Optical Science, Engineering, and Instrumentation, edited by Tomasz Jannson. SPIE, 1995. http://dx.doi.org/10.1117/12.221223.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Edge velocity"

1

Cao, A., S. J. Zweben, D. P. Stotler, M. Bell, A. Diallo, S. M. Kaye, and B. LeBlanc. Edge Turbulence Velocity Changes with Lithium Coating on NSTX. Office of Scientific and Technical Information (OSTI), August 2012. http://dx.doi.org/10.2172/1056824.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Munsat, Tobin. Assessment of Edge Turbulence and Convective Transport through Velocity Field Analysis. Office of Scientific and Technical Information (OSTI), March 2015. http://dx.doi.org/10.2172/1176964.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Ruvinsky, Alicia, Timothy Garton, Daniel Chausse, Rajeev Agrawal, Harland Yu, and Ernest Miller. Accelerating the tactical decision process with High-Performance Computing (HPC) on the edge : motivation, framework, and use cases. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42169.

Full text
Abstract:
Managing the ever-growing volume and velocity of data across the battlefield is a critical problem for warfighters. Solving this problem will require a fundamental change in how battlefield analyses are performed. A new approach to making decisions on the battlefield will eliminate data transport delays by moving the analytical capabilities closer to data sources. Decision cycles depend on the speed at which data can be captured and converted to actionable information for decision making. Real-time situational awareness is achieved by locating computational assets at the tactical edge. Accelerating the tactical decision process leverages capabilities in three technology areas: (1) High-Performance Computing (HPC), (2) Machine Learning (ML), and (3) Internet of Things (IoT). Exploiting these areas can reduce network traffic and shorten the time required to transform data into actionable information. Faster decision cycles may revolutionize battlefield operations. Presented is an overview of an artificial intelligence (AI) system design for near-real-time analytics in a tactical operational environment executing on co-located, mobile HPC hardware. The report contains the following sections, (1) an introduction describing motivation, background, and state of technology, (2) descriptions of tactical decision process leveraging HPC problem definition and use case, and (3) HPC tactical data analytics framework design enabling data to decisions.
APA, Harvard, Vancouver, ISO, and other styles
4

African Open Science Platform Part 1: Landscape Study. Academy of Science of South Africa (ASSAf), 2019. http://dx.doi.org/10.17159/assaf.2019/0047.

Full text
Abstract:
This report maps the African landscape of Open Science – with a focus on Open Data as a sub-set of Open Science. Data to inform the landscape study were collected through a variety of methods, including surveys, desk research, engagement with a community of practice, networking with stakeholders, participation in conferences, case study presentations, and workshops hosted. Although the majority of African countries (35 of 54) demonstrates commitment to science through its investment in research and development (R&D), academies of science, ministries of science and technology, policies, recognition of research, and participation in the Science Granting Councils Initiative (SGCI), the following countries demonstrate the highest commitment and political willingness to invest in science: Botswana, Ethiopia, Kenya, Senegal, South Africa, Tanzania, and Uganda. In addition to existing policies in Science, Technology and Innovation (STI), the following countries have made progress towards Open Data policies: Botswana, Kenya, Madagascar, Mauritius, South Africa and Uganda. Only two African countries (Kenya and South Africa) at this stage contribute 0.8% of its GDP (Gross Domestic Product) to R&D (Research and Development), which is the closest to the AU’s (African Union’s) suggested 1%. Countries such as Lesotho and Madagascar ranked as 0%, while the R&D expenditure for 24 African countries is unknown. In addition to this, science globally has become fully dependent on stable ICT (Information and Communication Technologies) infrastructure, which includes connectivity/bandwidth, high performance computing facilities and data services. This is especially applicable since countries globally are finding themselves in the midst of the 4th Industrial Revolution (4IR), which is not only “about” data, but which “is” data. According to an article1 by Alan Marcus (2015) (Senior Director, Head of Information Technology and Telecommunications Industries, World Economic Forum), “At its core, data represents a post-industrial opportunity. Its uses have unprecedented complexity, velocity and global reach. As digital communications become ubiquitous, data will rule in a world where nearly everyone and everything is connected in real time. That will require a highly reliable, secure and available infrastructure at its core, and innovation at the edge.” Every industry is affected as part of this revolution – also science. An important component of the digital transformation is “trust” – people must be able to trust that governments and all other industries (including the science sector), adequately handle and protect their data. This requires accountability on a global level, and digital industries must embrace the change and go for a higher standard of protection. “This will reassure consumers and citizens, benefitting the whole digital economy”, says Marcus. A stable and secure information and communication technologies (ICT) infrastructure – currently provided by the National Research and Education Networks (NRENs) – is key to advance collaboration in science. The AfricaConnect2 project (AfricaConnect (2012–2014) and AfricaConnect2 (2016–2018)) through establishing connectivity between National Research and Education Networks (NRENs), is planning to roll out AfricaConnect3 by the end of 2019. The concern however is that selected African governments (with the exception of a few countries such as South Africa, Mozambique, Ethiopia and others) have low awareness of the impact the Internet has today on all societal levels, how much ICT (and the 4th Industrial Revolution) have affected research, and the added value an NREN can bring to higher education and research in addressing the respective needs, which is far more complex than simply providing connectivity. Apart from more commitment and investment in R&D, African governments – to become and remain part of the 4th Industrial Revolution – have no option other than to acknowledge and commit to the role NRENs play in advancing science towards addressing the SDG (Sustainable Development Goals). For successful collaboration and direction, it is fundamental that policies within one country are aligned with one another. Alignment on continental level is crucial for the future Pan-African African Open Science Platform to be successful. Both the HIPSSA ((Harmonization of ICT Policies in Sub-Saharan Africa)3 project and WATRA (the West Africa Telecommunications Regulators Assembly)4, have made progress towards the regulation of the telecom sector, and in particular of bottlenecks which curb the development of competition among ISPs. A study under HIPSSA identified potential bottlenecks in access at an affordable price to the international capacity of submarine cables and suggested means and tools used by regulators to remedy them. Work on the recommended measures and making them operational continues in collaboration with WATRA. In addition to sufficient bandwidth and connectivity, high-performance computing facilities and services in support of data sharing are also required. The South African National Integrated Cyberinfrastructure System5 (NICIS) has made great progress in planning and setting up a cyberinfrastructure ecosystem in support of collaborative science and data sharing. The regional Southern African Development Community6 (SADC) Cyber-infrastructure Framework provides a valuable roadmap towards high-speed Internet, developing human capacity and skills in ICT technologies, high- performance computing and more. The following countries have been identified as having high-performance computing facilities, some as a result of the Square Kilometre Array7 (SKA) partnership: Botswana, Ghana, Kenya, Madagascar, Mozambique, Mauritius, Namibia, South Africa, Tunisia, and Zambia. More and more NRENs – especially the Level 6 NRENs 8 (Algeria, Egypt, Kenya, South Africa, and recently Zambia) – are exploring offering additional services; also in support of data sharing and transfer. The following NRENs already allow for running data-intensive applications and sharing of high-end computing assets, bio-modelling and computation on high-performance/ supercomputers: KENET (Kenya), TENET (South Africa), RENU (Uganda), ZAMREN (Zambia), EUN (Egypt) and ARN (Algeria). Fifteen higher education training institutions from eight African countries (Botswana, Benin, Kenya, Nigeria, Rwanda, South Africa, Sudan, and Tanzania) have been identified as offering formal courses on data science. In addition to formal degrees, a number of international short courses have been developed and free international online courses are also available as an option to build capacity and integrate as part of curricula. The small number of higher education or research intensive institutions offering data science is however insufficient, and there is a desperate need for more training in data science. The CODATA-RDA Schools of Research Data Science aim at addressing the continental need for foundational data skills across all disciplines, along with training conducted by The Carpentries 9 programme (specifically Data Carpentry 10 ). Thus far, CODATA-RDA schools in collaboration with AOSP, integrating content from Data Carpentry, were presented in Rwanda (in 2018), and during17-29 June 2019, in Ethiopia. Awareness regarding Open Science (including Open Data) is evident through the 12 Open Science-related Open Access/Open Data/Open Science declarations and agreements endorsed or signed by African governments; 200 Open Access journals from Africa registered on the Directory of Open Access Journals (DOAJ); 174 Open Access institutional research repositories registered on openDOAR (Directory of Open Access Repositories); 33 Open Access/Open Science policies registered on ROARMAP (Registry of Open Access Repository Mandates and Policies); 24 data repositories registered with the Registry of Data Repositories (re3data.org) (although the pilot project identified 66 research data repositories); and one data repository assigned the CoreTrustSeal. Although this is a start, far more needs to be done to align African data curation and research practices with global standards. Funding to conduct research remains a challenge. African researchers mostly fund their own research, and there are little incentives for them to make their research and accompanying data sets openly accessible. Funding and peer recognition, along with an enabling research environment conducive for research, are regarded as major incentives. The landscape report concludes with a number of concerns towards sharing research data openly, as well as challenges in terms of Open Data policy, ICT infrastructure supportive of data sharing, capacity building, lack of skills, and the need for incentives. Although great progress has been made in terms of Open Science and Open Data practices, more awareness needs to be created and further advocacy efforts are required for buy-in from African governments. A federated African Open Science Platform (AOSP) will not only encourage more collaboration among researchers in addressing the SDGs, but it will also benefit the many stakeholders identified as part of the pilot phase. The time is now, for governments in Africa, to acknowledge the important role of science in general, but specifically Open Science and Open Data, through developing and aligning the relevant policies, investing in an ICT infrastructure conducive for data sharing through committing funding to making NRENs financially sustainable, incentivising open research practices by scientists, and creating opportunities for more scientists and stakeholders across all disciplines to be trained in data management.
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Edge velocity' for particular source types:
Journal articles Dissertations / Theses
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography