1,624 research outputs found

    Open Cell Conducting Foams for High Synchrotron Radiation Beam Liners

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    The possible use of open-cell conductive foams in high synchrotron radiation particle accelerator beam liners is considered. Available materials and modeling tools are reviewed, potential pros and cons are discussed, and preliminary conclusions are drawn.Comment: 21 pages, 5 figures, 3 tables, 51 references, submitted to PR-STA

    The Quadratic Coefficient of the Electron Cloud Mapping

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    The Electron Cloud is an undesirable physical phenomenon which might produce single and multi-bunch instability, tune shift, increase of pressure ultimately limiting the performance of particle accelerators. We report our results on the analytical study of the electron dynamics.Comment: 5 pages, 7 figures, presented at ECLOUD12: Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects, La Biodola, Isola d Elba, Italy, 5-9 June 201

    A real time classification algorithm for EEG-based BCI driven by self-induced emotions

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    Background and objective: The aim of this paper is to provide an efficient, parametric, general, and completely automatic real time classification method of electroencephalography (EEG) signals obtained from self-induced emotions. The particular characteristics of the considered low-amplitude signals (a self-induced emotion produces a signal whose amplitude is about 15% of a really experienced emotion) require exploring and adapting strategies like the Wavelet Transform, the Principal Component Analysis (PCA) and the Support Vector Machine (SVM) for signal processing, analysis and classification. Moreover, the method is thought to be used in a multi-emotions based Brain Computer Interface (BCI) and, for this reason, an ad hoc shrewdness is assumed. Method: The peculiarity of the brain activation requires ad-hoc signal processing by wavelet decomposition, and the definition of a set of features for signal characterization in order to discriminate different self-induced emotions. The proposed method is a two stages algorithm, completely parameterized, aiming at a multi-class classification and may be considered in the framework of machine learning. The first stage, the calibration, is off-line and is devoted at the signal processing, the determination of the features and at the training of a classifier. The second stage, the real-time one, is the test on new data. The PCA theory is applied to avoid redundancy in the set of features whereas the classification of the selected features, and therefore of the signals, is obtained by the SVM. Results: Some experimental tests have been conducted on EEG signals proposing a binary BCI, based on the self-induced disgust produced by remembering an unpleasant odor. Since in literature it has been shown that this emotion mainly involves the right hemisphere and in particular the T8 channel, the classification procedure is tested by using just T8, though the average accuracy is calculated and reported also for the whole set of the measured channels. Conclusions: The obtained classification results are encouraging with percentage of success that is, in the average for the whole set of the examined subjects, above 90%. An ongoing work is the application of the proposed procedure to map a large set of emotions with EEG and to establish the EEG headset with the minimal number of channels to allow the recognition of a significant range of emotions both in the field of affective computing and in the development of auxiliary communication tools for subjects affected by severe disabilities

    Coupling Impedances for Perforated Beam Pipes with General Shape from Impedance Boundary Condition

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    We introduce an equivalent wall impedance to describe the electromagnetic boundary conditions at perforated pipe walls. The new impedance boundary condition, together with our general formulae for computing longitudinal and transverse beam coupling impedances in complex heterogeneous pipes, provides a good trade-off between computational accuracy and ease

    Mistreatment of Detainees in the War on Terror: How the Bush Administration’s Policies Have Violated International Law and Hurt America

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    The mistreatment of prisoners in U.S. custody between September 11, 2001, and January 2009, including in- definite detentions, unfair trials, the use of interroga- tion techniques amounting to torture, and the deportation of prisoners to other countries for the purpose of torture, constitute violations of international law. Contrary to what the Bush administration and its supporters have argued, these policies are illegal and have not been more effective at protecting the United States than legal methods. In fact, by reducing the moral standing of the country and alienating individuals throughout the world, especially Muslims, they have strengthened anti-American extremism and increased the danger of terrorist attacks against the United States

    Maps for Electron Clouds: Application to LHC Conditioning

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    In this communication we present a generalization of the map formalism, introduced in [1] and [2], to the analysis of electron flux at the chamber wall with particular reference to the exploration of LHC conditioning scenarios.Comment: 3 pages, 4 figure
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