3,565 research outputs found

    Flexible programmable networking: A reflective, component-based approach

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    The need for programmability and adaptability in networking systems is becoming increasingly important. More specifically, the challenge is in the ability to add services rapidly, and be able to deploy, configure and reconfigure them as easily as possible. Such demand is creating a considerable shift in the way networks are expected to operate in the future. This is the main aim of programmable networking research community, and in our project we are investigating a component-based approach to the structuring of programmable networking software. Our intention is to apply the notion of components, component frameworks and reflection ubiquitously, thus accommodating all the different elements that comprise a programmable networking system

    A critical discussion of calculated modulated structures, Fermi surface nesting and phonon softening in magnetic shape memory alloys Ni2_2Mn(Ga, Ge, Al) and Co2_2Mn(Ga, Ge)

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    A series of first principles calculations have been carried out in order to discuss electronic structure, phonon dynamics, structural instabilities and the nature of martensitic transformations of the Heusler alloys Ni2_2Mn(Ga, Ge, Al) and Co2_2Mn(Ga, Ge). The calculations show that besides electronic pecularities like Fermi--surface nesting, hybridizing optical and acoustic phonon modes are important for the stabilization of the modulated martensitic structures.Comment: 3 pages, 4 figures, JEMS-200

    Possibility of Searching for Fourth Generation Neutrino at Future ep Colliders

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    We investigate the production of fourth generation neutrino in the context of new eν4We \nu_4 W magnetic dipole moment type interaction in epep collisions at the future lepton-hadron colliders. We have obtained the mass limits of 700 GeV for THERA (S\sqrt S=1 TeV) and 2.8 TeV for LC\otimes LHC (S\sqrt S=3.74 TeV).Comment: 7 pages, 6 figures, typos adde

    Magnetization of Charge-ordered la(2-x)sr(x)nio(4+delta)

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    We report magnetization measurements on La(2-x)Sr(x)NiO(4+ delta) single crystals, with 0 < x < 0.5. Glassy behaviour associated with the formation of spin-charge stripes, and a separate spin-glass phase at low temperatures were observed. We have also found a `memory effect' in the magnetic field -- temperature history, which is found to be suppressed in the low temperature spin state of the x = 0.33 crystal.Comment: 2 pages, 2 figures. Presented at ICM2003 to appear in J. Magn. Magn. Mat

    Magnetic Order and Dynamics in Stripe-Ordered La2-xSrxNiO4

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    We have studied magnetic correlations in several compositions of stripe-ordered La2-xSrxNiO4. In this paper we show how polarized-neutron scattering has helped uncover important features of the magnetic ordering and spin dynamics. In particular, polarization analysis has enabled us (1) to characterize a spin reorientation transition, (2) to identify anisotropy gaps in the spin excitation spectrum, and (3) to investigate an anomalous dip in the spin-wave intensity suggestive of coupling between collective spin and charge excitations.Comment: 4 pages, 3 figs. Presented at PNSXM, Venice. To appear in Physica

    Transcranial Magnetic theta-burst stimulation of the human cerebellum distinguishes absolute, duration-based from relative, beat-based perception of subsecond time intervals

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    Cerebellar functions in two types of perceptual timing were assessed: the absolute (duration-based) timing of single intervals and the relative (beat-based) timing of rhythmic sequences. Continuous transcranial magnetic theta-burst stimulation (cTBS) was applied over the medial cerebellum and performance was measured adaptively before and after stimulation. A large and significant effect was found in the TBS (n = 12) compared to the SHAM (n = 12) group for single-interval timing but not for the detection of a regular beat or a deviation from it. The data support the existence of distinct perceptual timing mechanisms and an obligatory role of the cerebellum in absolute interval timing with a functional dissociation from relative timing of interval within rhythmic sequences based on a regular beat

    A contingency analysis of LeActiveMath's learner model

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    We analyse how a learner modelling engine that uses belief functions for evidence and belief representation, called xLM, reacts to different input information about the learner in terms of changes in the state of its beliefs and the decisions that it derives from them. The paper covers xLM induction of evidence with different strengths from the qualitative and quantitative properties of the input, the amount of indirect evidence derived from direct evidence, and differences in beliefs and decisions that result from interpreting different sequences of events simulating learners evolving in different directions. The results here presented substantiate our vision of xLM is a proof of existence for a generic and potentially comprehensive learner modelling subsystem that explicitly represents uncertainty, conflict and ignorance in beliefs. These are key properties of learner modelling engines in the bizarre world of open Web-based learning environments that rely on the content+metadata paradigm

    Mesh update techniques for free-surface flow solvers using spectral element method

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    This paper presents a novel mesh-update technique for unsteady free-surface Newtonian flows using spectral element method and relying on the arbitrary Lagrangian--Eulerian kinematic description for moving the grid. Selected results showing compatibility of this mesh-update technique with spectral element method are given

    Universal scaling of the Hall resistivity in MgB2 superconductors

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    The mixed-state Hall resistivity and the longitudinal resistivity in superconducting MgB2 thin films have been investigated as a function of the magnetic field over a wide range of current densities from 100 to 10000 A/cm^2. We observe a universal Hall scaling behavior with a constant exponent of 2.0, which is independent of the magnetic field, the temperature, and the current density. This result can be interpreted well within the context of recent theories.Comment: 4 page

    Operation o Solar Photovoltaic-Thermal (PVT) Hybrid System in KIER

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    The details of the Photovoltaic Thermal (PVT) hybrid air heating system, UTC air heating system and its effect on the performance of photovoltaic (PV) module and room temperature in KIER are explained in this paper. Two identical test rooms were constructed such that one had unglazed transpired collector on its south facing wall while other had no solar wall. The temperature inside the room with UTC was 10-20oC higher than the temperature inside the room without UTC on a typical winter day. In second set of experiments, 75W PV modules were installed on the south facing walls of each test rooms. The temperature of the PV module with UTC was 5-9?lower than the PV module without UTC resulting in a 6% recovery of output electrical power under the forced ventilation. PVT hybrid system may alleviate burden on conventional energy consumption in Korea for heating the buildings and electricity generation
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