Results 1 - 10 of 6,852

Boosting a Weak Learning Algorithm By Majority

by Yoav Freund , 1995
"... We present an algorithm for improving the accuracy of algorithms for learning binary concepts. The improvement is achieved by combining a large number of hypotheses, each of which is generated by training the given learning algorithm on a different set of examples. Our algorithm is based on ideas pr ..."
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upper bounds known today. We show that the number of hypotheses that are combined by our algorithm is the smallest number possible. Other outcomes of our analysis are results regarding the representational power of threshold circuits, the relation between learnability and compression, and a method

Pellet Fuelling and ELMy H-mode Physics in JET The JET Team 1, prepared by L.D. Horton 1) JET Joint Undertaking, Abingdon, U.K.

by unknown authors
"... Abstract. As the reference operating regime for ITER, investigations of the ELMy H-mode have received high priority in the JET experimental programme. Recent experiments have concentrated in particular on operation simultaneously at high density and high confinement using high field side (HFS) pelle ..."
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necessary to maintain the high confinement normally associated with ELMy Hmode operation is found to be substantially higher than the H-mode threshold power. The compatibility of ELMy H-modes with divertor operation acceptable for a fusion device has been studied. Narrow energy scrapeoff widths are measured

H-Mode Threshold and Confinement in Helium, Deuterium and Hydrogen in ASDEX Upgrade

by F. Ryter, M. Reich, A. Scarabosio, E. Wolfrum, R. Fischer, M. Gemisic Adamov, N. Hicks, B. Kurzan, C. Maggi, R. Neu, V. Rohde, G. Tardini, Asdex Upgrade Team
"... In 2008, experiments have been carried out in ASDEX Upgrade to compare H-mode power threshold, L-to-H transition and confinement time in helium and deuterium. For the power threshold, a scan in magnetic field and a wide density variation have been performed in the two gases. The threshold power for ..."
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In 2008, experiments have been carried out in ASDEX Upgrade to compare H-mode power threshold, L-to-H transition and confinement time in helium and deuterium. For the power threshold, a scan in magnetic field and a wide density variation have been performed in the two gases. The threshold power

Improved H-mode access with inboard gas puffing

by A. R. Field, E. R. Arends, P. G. Carolan, P. J. Catto, N. J. Conway, G. Cunningham, T. Fülöp, P. Hel, B. Lloyd, H. Meyer, M. J. Walsh, The Mast, Nbi Teams
"... Predicted threshold powers for H-mode access in the ITER device based on the latest empirical scalings from multi-machine databases exhibit large uncertainties (RMSE of 27%) due to effects which are difficult to quantify, such as wall conditioning and the behaviour of neutral atoms [1]. Experiments ..."
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Predicted threshold powers for H-mode access in the ITER device based on the latest empirical scalings from multi-machine databases exhibit large uncertainties (RMSE of 27%) due to effects which are difficult to quantify, such as wall conditioning and the behaviour of neutral atoms [1]. Experiments

Experimental Evidence for Electron Heat Transport Threshold in ASDEX Upgrade H-modes

by A Manini , F Ryter , C Angioni , M Apostoliceanu , A G Peeters , J Stober , G Tardini , F Leuterer , C F Maggi , D Nishijima , A Stäbler , W Suttrop , D Wagner , Upgrade Asdex , Team
"... Introduction and experimental conditions Electron temperature profiles in tokamak plasmas have been observed to weakly react to changes of the auxiliary heating power deposition profile. This property known as 'profile resilience' or 'profile stiffness', can be explained by an i ..."
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Introduction and experimental conditions Electron temperature profiles in tokamak plasmas have been observed to weakly react to changes of the auxiliary heating power deposition profile. This property known as 'profile resilience' or 'profile stiffness', can be explained

Efficient Mining of Emerging Patterns: Discovering Trends and Differences

by Guozhu Dong, Jinyan Li , 1999
"... We introduce a new kind of patterns, called emerging patterns (EPs), for knowledge discovery from databases. EPs are defined as itemsets whose supports increase significantly from one dataset to another. EPs can capture emerging trends in timestamped databases, or useful contrasts between data clas ..."
Abstract - Cited by 343 (40 self) - Add to MetaCart
classes. EPs have been proven useful: we have used them to build very powerful classifiers, which are more accurate than C4.5 and CBA, for many datasets. We believe that EPs with low to medium support, such as 1%-- 20%, can give useful new insights and guidance to experts, in even "well understood

Alpha heating in ITER L-mode and H-mode plasmas

by R. V. Budny , 2011
"... Predictions of alpha heating in ITER L-mode and H-mode DT plasmas are generated using the PTRANSP code. The baseline toroidal field (5.3 T), plasma current ramped to 15 MA and a flat electron density profile ramped to Greenwald fraction 0.85 are assumed. Various combinations of external heating by n ..."
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then the heating mixes with the highest neutral beam power (and the most alpha heating) transition to H-mode during the density ramp. Other heating mixes remain in L-mode. Predictions of H-mode temperatures and alpha heating depend sensitively on the assumed pedestal pressures. A scan in pedestal pressures

IAEA-CN-77/EXP5/26 Substantial Reduction of H-mode Transition Threshold Power in JT-60U

by K. Tsuchiya, T. Fukuda, H. Takenaga, N. Asakura, Y. Kamada, T. Takizuka, K. Itami
"... Abstract. Substantial reduction of the H-mode transition threshold power was observed under the W-shaped divertor in JT-60U, in comparison with the open divertor. Radiation power in main region was also decreased in this case. These difference of radiation power from the main plasma between open and ..."
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Abstract. Substantial reduction of the H-mode transition threshold power was observed under the W-shaped divertor in JT-60U, in comparison with the open divertor. Radiation power in main region was also decreased in this case. These difference of radiation power from the main plasma between open

Dependence of the L- to H-mode Power Threshold on Toroidal Rotation and the Link to Edge Turbulence Dynamics

by G. R. Mckee, P. Gohil, D. J. Schlossberg, J. A. Boedo, K. H. Burrell, T. L. Rhodes, G. Wang, A. E. White, X. Xu
"... Abstract. The injected power required to induce a transition from L-mode to H-mode plasmas is found to depend strongly on the injected neutral beam torque and consequent plasma toroidal rotation. Edge turbulence and flows, measured near the outboard midplane of the plasma (0.85 < r/a < 1.0) on ..."
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Abstract. The injected power required to induce a transition from L-mode to H-mode plasmas is found to depend strongly on the injected neutral beam torque and consequent plasma toroidal rotation. Edge turbulence and flows, measured near the outboard midplane of the plasma (0.85 < r/a < 1

Confinement Transitions (H-mode) in JET inner wall limiter plasmas

by D. Borba, B. Alper, G. D. Conway, I. Nunes, S. Hacquin, D. C. Mcdonald, G. Maddison, P. Lomas, S. D. Pinches, The Efda-jet Contributors
"... It is foreseen that the next step tokamak fusion experiment (ITER) will operate in improved confinement regimes such as the H-mode [F. Wagner et al]. H-mode is characterised by a spontaneous confinement transition that leads to an increase in plasma density and temperature, when the plasma heating p ..."
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It is foreseen that the next step tokamak fusion experiment (ITER) will operate in improved confinement regimes such as the H-mode [F. Wagner et al]. H-mode is characterised by a spontaneous confinement transition that leads to an increase in plasma density and temperature, when the plasma heating
Results 1 - 10 of 6,852