388,644 research outputs found

    Attacking the combination generator

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    We present one of the most efficient attacks against the combination generator. This attack is inherent to this system as its only assumption is that the filtering function has a good autocorrelation. This is usually the case if the system is designed to be resistant to other kinds of attacks. We use only classical tools, namely vectorial correlation, weight 4 multiples and Walsh transform

    Design and Development of Vapor Absorption Refrigeration System for Rural Dwellers

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    In this study, the experimental analysis of the performance of vapor absorption system was developed and developed. The influence of generator, evaporator and condenser’s temperatures on the system performance was studied using gas burner as source of energy, ammonia-water combination as working fluid and energy equations as governing equations for the work. There was variation in the results when compared with the earlier worker who used kerosene burner as source of energy and ammonia-water combination. Result of this study shows that if higher cooling capacity and also lower evaporator`s temperature are desired from the system, generator`s temperature should be increased considerably. Also the combination of an analyzer, rectifier and heat exchanger would produce better COP of the Syste

    Kaman 40 kW wind turbine generator - control system dynamics

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    The generator design incorporates an induction generator for application where a utility line is present and a synchronous generator for standalone applications. A combination of feed forward and feedback control is used to achieve synchronous speed prior to connecting the generator to the load, and to control the power level once the generator is connected. The dynamics of the drive train affect several aspects of the system operation. These were analyzed to arrive at the required shaft stiffness. The rotor parameters that affect the stability of the feedback control loop vary considerably over the wind speed range encountered. Therefore, the controller gain was made a function of wind speed in order to maintain consistent operation over the whole wind speed range. The velocity requirement for the pitch control mechanism is related to the nature of the wind gusts to be encountered, the dynamics of the system, and the acceptable power fluctuations and generator dropout rate. A model was developed that allows the probable dropout rate to be determined from a statistical model of wind gusts and the various system parameters, including the acceptable power fluctuation

    Symmetrization for Quantum Networks: a continuous-time approach

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    In this paper we propose a continuous-time, dissipative Markov dynamics that asymptotically drives a network of n-dimensional quantum systems to the set of states that are invariant under the action of the subsystem permutation group. The Lindblad-type generator of the dynamics is built with two-body subsystem swap operators, thus satisfying locality constraints, and preserve symmetric observables. The potential use of the proposed generator in combination with local control and measurement actions is illustrated with two applications: the generation of a global pure state and the estimation of the network size.Comment: submitted to MTNS 201

    Biomedical ultrasonoscope

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    The combination of a "C" mode scan electronics in a portable, battery powered biomedical ultrasonoscope having "A" and "M" mode scan electronics, the latter including a clock generator for generating clock pulses, a cathode ray tube having X, Y and Z axis inputs, a sweep generator connected between the clock generator and the X axis input of the cathode ray tube for generating a cathode ray sweep signal synchronized by the clock pulses, and a receiver adapted to be connected to the Z axis input of the cathode ray tube. The "C" mode scan electronics comprises a plurality of transducer elements arranged in a row and adapted to be positioned on the skin of the patient's body for converting a pulsed electrical signal to a pulsed ultrasonic signal, radiating the ultrasonic signal into the patient's body, picking up the echoes reflected from interfaces in the patient's body and converting the echoes to electrical signals; a plurality of transmitters, each transmitter being coupled to a respective transducer for transmitting a pulsed electrical signal thereto and for transmitting the converted electrical echo signals directly to the receiver, a sequencer connected between the clock generator and the plurality of transmitters and responsive to the clock pulses for firing the transmitters in cyclic order; and a staircase voltage generator connected between the clock generator and the Y axis input of the cathode ray tube for generating a staircase voltage having steps synchronized by the clock pulses

    Distribution of periodic trajectories of Anosov C-system

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    The hyperbolic Anosov C-systems have a countable set of everywhere dense periodic trajectories which have been recently used to generate pseudorandom numbers. The asymptotic distribution of periodic trajectories of C-systems with periods less than a given number is well known, but a deviation of this distribution from its asymptotic behaviour is less known. Using fast algorithms, we are studying the exact distribution of periodic trajectories and their deviation from asymptotic behaviour for hyperbolic C-systems which are defined on high dimensional tori and are used for Monte-Carlo simulations. A particular C-system which we consider in this article is the one which was implemented in the MIXMAX generator of pseudorandom numbers. The generator has the best combination of speed, reasonable size of the state, and availability for implementing the parallelization and is currently available generator in the ROOT and CLHEP software packages at CERN.Comment: 22 pages, 14 figure

    Searching for L-Violating Supersymmetry at the LHC

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    The possibility to simulate lepton number violating supersymmetric models has been introduced into the recently updated PYTHIA event generator, now containing 1278 decay channels of SUSY particles into SM particles via lepton number violating interactions. This generator has been used in combination with the ATLFAST detector simulation to study the impact of lepton number violation (LV) on event topologies in the ATLAS detector, and trigger menus designed for LV-SUSY are proposed based on very general considerations. In addition, a rather preliminary analysis is presented on the possibility for ATLAS to observe a signal above the background in several mSUGRA scenarios, using a combination of primitive cuts and neural networks to optimize the discriminating power between signal and background events over regions of parameter space rather than at individual points. It is found that a 5 sigma discovery is possible roughly for m_{1/2} < 1TeV and m_0 < 2TeV with an integrated luminosity of 30fb^{-1}, corresponding to one year of data taking with the LHC running at ``mid-luminosity'', L = 3*10^{33}s^{-1}cm^{-2}.Comment: 12 page
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