5,718 research outputs found

    Auctioning Bulk Mobile Messages

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    The search for enablers of continued growth of SMS traffic, as well asthe take-off of the more diversified MMS message contents, open up forenterprises the potential of bulk use of mobile messaging , instead ofessentially one-by-one use. In parallel, such enterprises or valueadded services needing mobile messaging in bulk - for spot use or foruse over a prescribed period of time - want to minimize totalacquisition costs, from a set of technically approved providers ofmessaging capacity.This leads naturally to the evaluation of auctioning for bulk SMS orMMS messaging capacity, with the intrinsic advantages therein such asreduction in acquisition costs, allocation efficiency, and optimality.The paper shows, with extensive results as evidence from simulationscarried out in the Rotterdam School of Management e-Auction room, howmulti-attribute reverse auctions perform for the enterprise-buyer, aswell as for the messaging capacity-sellers. We compare 1- and 5-roundauctions, to show the learning effect and the benefits thereof to thevarious parties. The sensitivity will be reported to changes in theenterprise's and the capacity providers utilities and prioritiesbetween message attributes (such as price, size, security, anddelivery delay). At the organizational level, the paper also considersalternate organizational deployment schemes and properties for anoff-line or spot bulk messaging capacity market, subject to technicaland regulatory constraints.MMS;EMS;Mobile commerce;SMS;multi-attribute auctions

    Examining the Effect of Pore Size Distribution and Shape on Flow through Unsaturated Peat using Computer Tomography

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    The hydraulic conductivity of unsaturated peat soil is controlled by the air-filled porosity, pore size and geometric distribution as well as other physical properties of peat materials. This study investigates how the size and shape of pores affects the flow of water through peat soils. In this study we used X-ray Computed Tomography (CT), at 45μm resolution under 5 specific soil-water pressure head levels to provide 3-D, high-resolution images that were used to detect the inner pore structure of peat samples under a changing water regime. Pore structure and configuration were found to be irregular, which affected the rate of water transmission through peat soils. The 3-D analysis suggested that pore distribution is dominated by a single large pore-space. At low pressure head, this single large air-filled pore imparted a more effective flowpath compared to smaller pores. Smaller pores were disconnected and the flowpath was more tortuous than in the single large air-filled pore, and their contribution to flow was negligible when the single large pore was active. We quantify the pore structure of peat soil that affects the hydraulic conductivity in the unsaturated condition, and demonstrate the validity of our estimation of peat unsaturated hydraulic conductivity by making a comparison with a standard permeameter-based method. Estimates of unsaturated hydraulic conductivities were made for the purpose of testing the sensitivity of pore shape and geometry parameters on the hydraulic properties of peats and how to evaluate the structure of the peat and its affects on parameterization. We also studied the ability to quantify these factors for different soil moisture contents in order to define how the factors controlling the shape coefficient vary with changes in soil water pressure head. The relation between measured and estimated unsaturated hydraulic conductivity at various heads shows that rapid initial drainage, that changes the air-filled pore properties, creates a sharp decline in hydraulic conductivity. This is because the large pores readily lose water, the peat rapidly becomes less conductive and the flow path among pores, more tortuous

    Resistance of LHC main bus bar splices at room temperature and at 77.4 K

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    As part of the quality control the resistance of newly produced LHC main bus bar splices is now routinely measured at room temperature (RT) in order to conclude on the electrical continuity of the bus bar stabiliser across the splice under operating conditions. In this note we present splice resistance measurements that have been performed at RT and in liquid nitrogen (LN) in the CERN Cryolab with “ideal” splices (represented by continuous dipole and quadrupole bus bars), and with dipole and quadrupole splices with different defects, which cause an additional RT splice resistance of up to 60 µΩ. The RT resistance (RRT) results obtained with the Cryolab set-up are compared to the calculated resistance values and with the so-called R-8 and R-16 resistance results, as they are measured in the LHC tunnel with a Digital Low Resistance Ohmmeter with a voltage tap distance of 8 cm or 16 cm. The RT to LN resistance ratio has been determined for all splices in order to study the influence of the resistance of the splice contact surfaces on the overall splice resistance

    Envelope tracking of a radio frequency amplifier for Long Term Evolution using a three-level class-G modulator

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    In this contribution, efficiency enhancement of a radio frequency (RF) power amplifier (PA) for Long Term Evolution (LTE) base stations using envelope tracking is investigated. The dynamically adapted drain bias voltage is provided by a three-level class-G modulator. The potential of this bias modulator is demonstrated with a class AB PA built in gallium nitride (GaN) technology with an operation frequency of 2.75 GHz, a maximum output power of 41 dBm and a peak power-added efficiency (PAE) of 60%. When driven by an LTE signal with a bandwidth of 20 MHz, overall system efficiency can be increased from 17% with a constant supply voltage up to 29% with envelope tracking. This is accompanied by a reduction of linearity. Adjacent channel leakage ratio (ACLR) decreases by 10 dB in the first and by 18 dB in the second adjacent channel, respectively. Error vector magnitude (EVM) increases from 9% up to 29%

    Визнання арбітражної угоди недійсною

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    У статті розглянуто питання недійсності арбітражної угоди, визначені етапи, на яких виникає дане питання, досліджені підстави для визнання арбітражної угоди недійсною.В статье рассмотрен вопрос недействительности арбитражного соглашения, определены этапы, на которых возникает данный вопрос, исследованы основания для признания арбитражного соглашения недействительным.This article analyses the issue of invalidity of the arbitration agreement, marks out the stages on which this matter arises, examines the grounds for invalidity of the arbitration agreement

    Fermion Quasi-Spherical Harmonics

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    Spherical Harmonics, Ym(θ,ϕ)Y_\ell^m(\theta,\phi), are derived and presented (in a Table) for half-odd-integer values of \ell and mm. These functions are eigenfunctions of L2L^2 and LzL_z written as differential operators in the spherical-polar angles, θ\theta and ϕ\phi. The Fermion Spherical Harmonics are a new, scalar and angular-coordinate-dependent representation of fermion spin angular momentum. They have 4π4\pi symmetry in the angle ϕ\phi, and hence are not single-valued functions on the Euclidean unit sphere; they are double-valued functions on the sphere, or alternatively are interpreted as having a double-sphere as their domain.Comment: 16 pages, 2 Tables. Submitted to J.Phys.

    Formation of fractal structure in many-body systems with attractive power-law potentials

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    We study the formation of fractal structure in one-dimensional many-body systems with attractive power-law potentials. Numerical analysis shows that the range of the index of the power for which fractal structure emerges is limited. Dependence of the growth rate on wavenumber and power-index is obtained by linear analysis of the collisionless Boltzmann equation, which supports the numerical results.Comment: accepted by PR

    Auctioning Bulk Mobile Messages

    Get PDF
    The search for enablers of continued growth of SMS traffic, as well as the take-off of the more diversified MMS message contents, open up for enterprises the potential of bulk use of mobile messaging , instead of essentially one-by-one use. In parallel, such enterprises or value added services needing mobile messaging in bulk - for spot use or for use over a prescribed period of time - want to minimize total acquisition costs, from a set of technically approved providers of messaging capacity. This leads naturally to the evaluation of auctioning for bulk SMS or MMS messaging capacity, with the intrinsic advantages therein such as reduction in acquisition costs, allocation efficiency, and optimality. The paper shows, with extensive results as evidence from simulations carried out in the Rotterdam School of Management e-Auction room, how multi-attribute reverse auctions perform for the enterprise-buyer, as well as for the messaging capacity-sellers. We compare 1- and 5-round auctions, to show the learning effect and the benefits thereof to the various parties. The sensitivity will be reported to changes in the enterprise's and the capacity providers utilities and priorities between message attributes (such as price, size, security, and delivery delay). At the organizational level, the paper also considers alternate organizational deployment schemes and properties for an off-line or spot bulk messaging capacity market, subject to technical and regulatory constraints
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