4,842 research outputs found

    Identifying how automation can lose its intended benefit along the development process : a research plan

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    Doctoral Consortium Presentation © The Authors 2009Automation is usually considered to improve performance in virtually any domain. However it can fail to deliver the target benefit as intended by those managers and designers advocating the introduction of the tool. In safety critical domains this problem is of significance not only because the unexpected effects of automation might prevent its widespread usage but also because they might turn out to be a contributor to incident and accidents. Research on failures of automation to deliver the intended benefit has focused mainly on human automation interaction. This paper presents a PhD research plan that aims at characterizing decisions for those involved in development process of automation for safety critical domains, taken under productive pressure, to identify where and when the initial intention the automation is supposed to deliver can be lost along the development process. We tentatively call such decisions as drift and the final objective is to develop principles that will allow to identify and compensate for possible sources of drift in the development of new automation. The research is based on case studies and is currently entering Year 2

    Beyond the Standard Model

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    The standard model of particle physics is marvelously successful. However, it is obviously not a complete or final theory. I shall argue here that the structure of the standard model gives some quite concrete, compelling hints regarding what lies beyond.Comment: 20 pages, 3 figures available upon request, IAS-HEP 92/2

    Conformality and Gauge Coupling Unification

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    It has been recently proposed to embed the standard model in a conformal gauge theory to resolve the hierarchy problem, and to avoid assuming either grand unification or low-energy supersymmetry. By model building based on string-field duality we show how to maintain the successful prediction of an electroweak mixing angle with sin2θ0.231sin^2\theta \simeq 0.231 in conformal gauge theories with three chiral families.Comment: 8 pages LaTe

    The Paths of Unification In The GUST With The G x G Gauge Groups of E(8) x E(8)

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    In the framework of the four dimensional heterotic superstring with free fermions we discuss the rank eight and/or sixteen Grand Unified String Theories (GUST) which contain the SU(3)_H - gauge family symmetry. We explicitly investigate the paths of the unification in the GUST with gauge symmetry G x G = [SU(5) x U(1) x (SU(3) x U(1))_H]^2. We show that the GUSTs with the G x G gauge group allow to make the scale of unification to be consistent with the string scale M_SU = g_{string} * 5 * 10^17 GeV.Comment: 18 pages, 2 Postscript figures, uses epsf.st

    The perturbative odderon in elastic p p and p pbar scattering

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    Different models for the odderon-proton coupling are considered and their effects on the differential cross section in the dip region in elastic p p and p pbar scattering are investigated. An allowed range for the size of a possible diquark cluster in the proton can be obtained from a geometrical model.Comment: Talk presented at the conference QCD 02 in Montpellier, France. 4 pages, 3 figure

    A theorem on the real part of the high-energy scattering amplitude near the forward direction

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    We show that if for fixed negative (physical) square of the momentum transfer t, the differential cross-section dσdt{d\sigma\over dt} tends to zero and if the total cross-section tends to infinity, when the energy goes to infinity, the real part of the even signature amplitude cannot have a constant sign near t = 0.Comment: 7 pages, late

    MSSM from SUSY Trinification

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    We construct a SU(3)3SU(3)^3 supersymmetric gauge theory with a common gauge coupling g. Spontaneous breaking of this gauge group at a scale MX=1.3×1016M_X=1.3\times10^{16} GeV gives naturally rise exactly to the Minimal Supersymmetric Standard Model (MSSM)(MSSM) and consequently to the experimentally favored values of sin2θwsin^2\theta_w and αs\alpha_s.The gauge hierarchy problem is naturally solved by a missing-partner-type mechanism which works to all orders in the superpotential. The baryon asymmetry can be generated in spite of the (essential) stability of the proton. The solar neutrino puzzle is solved by the MSW mechanism. The LSP is a natural "cold" dark matter candidate and "hot" dark matter might consist of τ\tau-neutrinos. This model could be thought of as an effective 4d4d theory emerging from a more fundamental theory at a scale Mc=MP/8πM_c=M_P/\sqrt{8\pi} where aGg24πa_G\equiv{g^2\over{4\pi}} happens to be equal to unity.Comment: 10 pages, LaTeX,UT-STPD-2-9

    Present challenges in hadrontherapy techniques

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    Hadrontherapy is a high-precision technique in cancer radiation therapy, which allows obtaining a superior conformal treatment with respect to photons used in conventional radiation therapy. To reach this ambitious goal without reducing the patient throughput needed in a hospital-based environment, the physical and radiobiological properties of charged hadrons, protons and carbon ions in particular, have to be exploited at best, making use of the most modern technologies issued from research in nuclear and particle physics. In the present days, we are assisting to a continuous technological challenge, leading to the conception and to the development of innovative methods and instruments. In this paper, the most relevant challenges in dose delivery systems, gantries, imaging, quality assurance and particle accelerators are reviewe

    High-power test results of a 3 GHz single-cell cavity

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    Compact, reliable and little consuming accelerators are required for the treatment of tumours with ions. TERA proposes the "cyclinac", composed of a high-frequency, fast-cycling linac which boosts the energy of the particles previously accelerated in a cyclotron. The dimensions of the linac can be reduced if high gradients are used. TERA initiated a high-gradient test program to understand the operational limit of such structures. The program foresees the design, prototyping and high-power test of several high-gradient structures operating at 3 and 5.7 GHz. The high-power tests of the 3 GHz single-cell cavity were completed in Winter 2012. The maximum BDR threshold measured for Emax of 170 MV/m and RF pulses of 2.5 \mu s was 3 x 10-6 bpp/m
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