2,301 research outputs found

    New distributed offline processing scheme at Belle

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    The offline processing of the data collected by the Belle detector has been recently upgraded to cope with the excellent performance of the KEKB accelerator. The 127/fb of data (120 TB on tape) collected between autumn 2003 and summer 2004 has been processed in 2 months, thanks to the high speed and stability of the new, distributed processing scheme. We present here this new processing scheme and its performance.Comment: 4 pages, 8 figures, uses CHEP2004.cl

    Human-robot coexistence and interaction in open industrial cells

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    Recent research results on human\u2013robot interaction and collaborative robotics are leaving behind the traditional paradigm of robots living in a separated space inside safety cages, allowing humans and robot to work together for completing an increasing number of complex industrial tasks. In this context, safety of the human operator is a main concern. In this paper, we present a framework for ensuring human safety in a robotic cell that allows human\u2013robot coexistence and dependable interaction. The framework is based on a layered control architecture that exploits an effective algorithm for online monitoring of relative human\u2013robot distance using depth sensors. This method allows to modify in real time the robot behavior depending on the user position, without limiting the operative robot workspace in a too conservative way. In order to guarantee redundancy and diversity at the safety level, additional certified laser scanners monitor human\u2013robot proximity in the cell and safe communication protocols and logical units are used for the smooth integration with an industrial software for safe low-level robot control. The implemented concept includes a smart human-machine interface to support in-process collaborative activities and for a contactless interaction with gesture recognition of operator commands. Coexistence and interaction are illustrated and tested in an industrial cell, in which a robot moves a tool that measures the quality of a polished metallic part while the operator performs a close evaluation of the same workpiece

    Frequentist Analysis of the Parameter Space of Minimal Supergravity

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    We make a frequentist analysis of the parameter space of minimal supergravity (mSUGRA), in which, as well as the gaugino and scalar soft supersymmetry-breaking parameters being universal, there is a specific relation between the trilinear, bilinear and scalar supersymmetry-breaking parameters, A_0 = B_0 + m_0, and the gravitino mass is fixed by m_{3/2} = m_0. We also consider a more general model, in which the gravitino mass constraint is relaxed (the VCMSSM). We combine in the global likelihood function the experimental constraints from low-energy electroweak precision data, the anomalous magnetic moment of the muon, the lightest Higgs boson mass M_h, B physics and the astrophysical cold dark matter density, assuming that the lightest supersymmetric particle (LSP) is a neutralino. In the VCMSSM, we find a preference for values of m_{1/2} and m_0 similar to those found previously in frequentist analyses of the constrained MSSM (CMSSM) and a model with common non-universal Higgs masses (NUHM1). On the other hand, in mSUGRA we find two preferred regions: one with larger values of both m_{1/2} and m_0 than in the VCMSSM, and one with large m_0 but small m_{1/2}. We compare the probabilities of the frequentist fits in mSUGRA, the VCMSSM, the CMSSM and the NUHM1: the probability that mSUGRA is consistent with the present data is significantly less than in the other models. We also discuss the mSUGRA and VCMSSM predictions for sparticle masses and other observables, identifying potential signatures at the LHC and elsewhere.Comment: 18 pages 27 figure

    Measurement of mechanical vibrations excited in aluminium resonators by 0.6 GeV electrons

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    We present measurements of mechanical vibrations induced by 0.6 GeV electrons impinging on cylindrical and spherical aluminium resonators. To monitor the amplitude of the resonator's vibrational modes we used piezoelectric ceramic sensors, calibrated by standard accelerometers. Calculations using the thermo-acoustic conversion model, agree well with the experimental data, as demonstrated by the specific variation of the excitation strengths with the absorbed energy, and with the traversing particles' track positions. For the first longitudinal mode of the cylindrical resonator we measured a conversion factor of 7.4 +- 1.4 nm/J, confirming the model value of 10 nm/J. Also, for the spherical resonator, we found the model values for the L=2 and L=1 mode amplitudes to be consistent with our measurement. We thus have confirmed the applicability of the model, and we note that calculations based on the model have shown that next generation resonant mass gravitational wave detectors can only be expected to reach their intended ultra high sensitivity if they will be shielded by an appreciable amount of rock, where a veto detector can reduce the background of remaining impinging cosmic rays effectively.Comment: Tex-Article with epsfile, 34 pages including 13 figures and 5 tables. To be published in Rev. Scient. Instr., May 200

    QoSatAr: a cross-layer architecture for E2E QoS provisioning over DVB-S2 broadband satellite systems

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    This article presents QoSatAr, a cross-layer architecture developed to provide end-to-end quality of service (QoS) guarantees for Internet protocol (IP) traffic over the Digital Video Broadcasting-Second generation (DVB-S2) satellite systems. The architecture design is based on a cross-layer optimization between the physical layer and the network layer to provide QoS provisioning based on the bandwidth availability present in the DVB-S2 satellite channel. Our design is developed at the satellite-independent layers, being in compliance with the ETSI-BSM-QoS standards. The architecture is set up inside the gateway, it includes a Re-Queuing Mechanism (RQM) to enhance the goodput of the EF and AF traffic classes and an adaptive IP scheduler to guarantee the high-priority traffic classes taking into account the channel conditions affected by rain events. One of the most important aspect of the architecture design is that QoSatAr is able to guarantee the QoS requirements for specific traffic flows considering a single parameter: the bandwidth availability which is set at the physical layer (considering adaptive code and modulation adaptation) and sent to the network layer by means of a cross-layer optimization. The architecture has been evaluated using the NS-2 simulator. In this article, we present evaluation metrics, extensive simulations results and conclusions about the performance of the proposed QoSatAr when it is evaluated over a DVB-S2 satellite scenario. The key results show that the implementation of this architecture enables to keep control of the satellite system load while guaranteeing the QoS levels for the high-priority traffic classes even when bandwidth variations due to rain events are experienced. Moreover, using the RQM mechanism the user’s quality of experience is improved while keeping lower delay and jitter values for the high-priority traffic classes. In particular, the AF goodput is enhanced around 33% over the drop tail scheme (on average)

    Predictions for Supersymmetric Particle Masses in the CMSSM using Indirect Experimental and Cosmological Constraints

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    In view of the imminent start of the LHC experimental programme, we use the available indirect experimental and cosmological information to estimate the likely range of parameters of the constrained minimal supersymmetric extension of the Standard Model (CMSSM), using a Markov-chain Monte Carlo (MCMC) technique to sample the parameter space. The 95% confidence-level area in the (m_0, m_1/2) plane of the CMSSM lies largely within the region that could be explored with 1/fb of integrated luminosity at 14 TeV, and much of the 68% confidence-level area lies within the region that could be explored with 50/pb of integrated luminosity at 10 TeV. A same-sign dilepton signal could well be visible in most of the 68% confidence-level area with 1/fb of integrated luminosity at 14 TeV. We discuss the sensitivities of the preferred ranges to variations in the most relevant indirect experimental and cosmological constraints and also to deviations from the universality of the supersymmetry-breaking contributions to the masses of the Higgs bosons.Comment: 19 pages, 7 figure

    Search for correlation between GRB's detected by BeppoSAX and gravitational wave detectors EXPLORER and NAUTILUS

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    Data obtained during five months of 2001 with the gravitational wave (GW) detectors EXPLORER and NAUTILUS were studied in correlation with the gamma ray burst data (GRB) obtained with the BeppoSAX satellite. During this period BeppoSAX was the only GRB satellite in operation, while EXPLORER and NAUTILUS were the only GW detectors in operation. No correlation between the GW data and the GRB bursts was found. The analysis, performed over 47 GRB's, excludes the presence of signals of amplitude h >=1.2 * 10^{-18}, with 95 % probability, if we allow a time delay between GW bursts and GRB within +-400 s, and h >= 6.5 * 10^{-19}, if the time delay is within +- 5 s. The result is also provided in form of scaled likelihood for unbiased interpretation and easier use for further analysis.Comment: 14 pages, 7 figures. Latex file, compiled with cernik.cls (provided in the package

    All-sky search of NAUTILUS data

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    A search for periodic gravitational-wave signals from isolated neutron stars in the NAUTILUS detector data is presented. We have analyzed half a year of data over the frequency band Hz,thespindownrange Hz, the spindown range Hz/s and over the entire sky. We have divided the data into 2 day stretches and we have analyzed each stretch coherently using matched filtering. We have imposed a low threshold for the optimal detection statistic to obtain a set of candidates that are further examined for coincidences among various data stretches. For some candidates we have also investigated the change of the signal-to-noise ratio when we increase the observation time from two to four days. Our analysis has not revealed any gravitational-wave signals. Therefore we have imposed upper limits on the dimensionless gravitational-wave amplitude over the parameter space that we have searched. Depending on frequency, our upper limit ranges from 3.4×10233.4 \times 10^{-23} to 1.3×10221.3 \times 10^{-22}. We have attempted a statistical verification of the hypotheses leading to our conclusions. We estimate that our upper limit is accurate to within 18%.Comment: LaTeX, 12 page
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