9,190 research outputs found

    Penerapan Metode Profile Matching untuk Menentukan Peserta Lomba Pramuka

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    Perkembangan zaman menuntut manusia untuk menguasai ilmu pengetahuan. Terutama untuk meraih prestasi sebagai pelajar, khususnya untuk melanjutkan ke jenjang selanjutnya /jalur prestasi, Untuk mendapatkan sebuah prestasi sangatlah tidak mudah, salah satunya dibidang lomba kepramukaan, butuh USAha dan latihan yang keras, serta seleksi yang ketat untuk menjadi peserta lomba SMK Negeri 1 Kota Bogor. Maka dari itu diperlukan suatu sistem yang dapat memperhitungkan segala kriteria yang mendukung dalam pengambilan keputusan calon peserta lomba. Pengambilan keputusan dengan menggunakan Metode Profile Matching merupakan hal yang tepat untuk menseleksi siswa apakah cocok untuk lomba dibidang tertentu. Hasil keputusan dari sistem profile matching berdasarkan nilai akhir dari penelitian, menyatakan bahwa jika nilai probabilitas YA lebih besar dari probabilitas TIDAK, maka sistem bekerja dengan baik, sebaliknya jika nilai probabilitas TIDAK lebih tinggi dari probabilitas YA, maka sistem tidak bekerja dengan baik. Dari hasil penelitian untuk unjuk kerja sistem profile matching masuk dalam kategori “Layak”. Nilai persentase hasil pengujian pada sistem untuk setiap faktor, yaitu: functionality sebesar 69 %, efficiency sebesar 70 %, dan USAbility sebesar 65%. Persentase total dari kualitas sistem adalah 90% (Layak)

    Automatic transmission: ethnicity, racialization and the car

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    YesThis article is based on ethnographic research carried out in Bradford, an ethnically diverse city situated in the north of England. The sample of over 60 participants mostly comprises males of British Pakistani Muslim heritage but varies in terms other markers of identity such as social class, profession and residential/working locale. The article analyses the cultural value and meaning of cars within a multicultural context and how a consumer object can feed into the processes which refine and embed racialized identities. Small cases studies reveal the concrete and discursive ways through which ideas around identity and ethnicity are transmitted and how, in particular, racialization continues to feature as a live, active and recognisable process in everyday experience

    Yang-Mills condensate dark energy coupled with matter and radiation

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    The coincidence problem is studied for the dark energy model of effective Yang-Mills condensate in a flat expanding universe during the matter-dominated stage. The YMC energy ρy(t)\rho_y(t) is taken to represent the dark energy, which is coupled either with the matter, or with both the matter and the radiation components. The effective YM Lagrangian is completely determined by quantum field theory up to 1-loop order. It is found that under very generic initial conditions and for a variety of forms of coupling, the existence of the scaling solution during the early stages and the subsequent exit from the scaling regime are inevitable. The transition to the accelerating stage always occurs around a redshift z≃(0.3∌0.5)z\simeq (0.3\sim 0.5). Moreover, when the Yang-Mills condensate transfers energy into matter or into both matter and radiation, the equation of state wyw_y of the Yang-Mills condensate can cross over -1 around z∌2z\sim 2, and takes on a current value ≃−1.1\simeq -1.1. This is consistent with the recent preliminary observations on supernovae Ia. Therefore, the coincidence problem can be naturally solved in the effective YMC dark energy models.Comment: 24 pages, 18 figure

    Photons from Quark Gluon Plasma and Hot Hadronic Matter

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    The productions of real photons from quark gluon plasma and hot hadronic matter formed after the nucleus - nucleus collisions at ultra-relativistic energies are discussed. The effects of the spectral shift of the hadrons at finite temperature on the production of photons are investigated. On the basis of the present analysis it is shown that the photon spectra measured by WA98 collaboration in Pb + Pb collisions at CERN SPS energies can be explained by both QGP as well as hadronic initial states if the spectral shift of hadrons at finite temperature is taken into account. Several other works on the analysis of WA98 photon data have also been briefly discussed.Comment: Latex file, six eps figures include

    Recent progress in the development of few mode fiber amplifier

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    We review the performances of both core and cladding pumped few-mode erbium doped fiber amplifiers supporting 6 spatial modes (4 mode groups) which incidentally the highest mode count demonstrated to date

    Chameleon field and the late time acceleration of the universe

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    In the present work, it is shown that a chameleon scalar field having a nonminimal coupling with dark matter can give rise to a smooth transition from a decelerated to an accelerated phase of expansion for the universe. It is surprising to note that the coupling with the chameleon scalar field hardly affects the evolution of the dark matter sector, which still redshifts as a−3a^{-3}.Comment: 7 pages, 2 figure

    Enskog Theory for Polydisperse Granular Mixtures. I. Navier-Stokes order Transport

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    A hydrodynamic description for an ss-component mixture of inelastic, smooth hard disks (two dimensions) or spheres (three dimensions) is derived based on the revised Enskog theory for the single-particle velocity distribution functions. In this first portion of the two-part series, the macroscopic balance equations for mass, momentum, and energy are derived. Constitutive equations are calculated from exact expressions for the fluxes by a Chapman-Enskog expansion carried out to first order in spatial gradients, thereby resulting in a Navier-Stokes order theory. Within this context of small gradients, the theory is applicable to a wide range of restitution coefficients and densities. The resulting integral-differential equations for the zeroth- and first-order approximations of the distribution functions are given in exact form. An approximate solution to these equations is required for practical purposes in order to cast the constitutive quantities as algebraic functions of the macroscopic variables; this task is described in the companion paper.Comment: 36 pages, to be published in Phys. Rev.

    Sfermion Pair Production in Polarized and Unpolarized γγ\gamma\gamma Collisions

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    We calculate total and differential cross sections for the production of sfermion pairs in photon-photon collisions, including contributions from resolved photons and arbitrary photon polarization. Sfermion production in photon collisions depends only on the sfermion mass and charge. It is thus independent of the details of the SUSY breaking mechanism, but highly sensitive to the sfermion charge. We compare the total cross sections for bremsstrahlung, beamstrahlung, and laser backscattering photons to those in e+e−e^+e^- annihilation. We find that the total cross section at a polarized photon collider is larger than the e+e−e^+e^- annihilation cross section up to the kinematic limit of the photon collider.Comment: 19 pages, Latex, 18 (e)ps-figure

    Equilibration in Quark Gluon Plasma

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    The hydrodynamic expansion rate of quark gluon plasma (QGP) is evaluated and compared with the scattering rate of quarks and gluons within the system. Partonic scattering rates evaluated within the ambit of perturbative Quantum Choromodynamics (pQCD) are found to be smaller than the expansion rate evaluated with ideal equation of state (EoS) for the QGP. This indicate that during the space-time evolution the system remains out of equilibrium. Enhancement of pQCD cross sections and a more realistic EoS keep the partons closer to the equilibrium.Comment: To be published in the Quark Matter 2008 poster proceeding

    Are direct photons a clean signal of a thermalized quark gluon plasma?

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    Direct photon production from a quark gluon plasma (QGP) in thermal equilibrium is studied directly in real time. In contrast to the usual S-matrix calculations, the real time approach is valid for a QGP that formed and reached LTE a short time after a collision and of finite lifetime (∌10−20fm/c\sim 10-20 \mathrm{fm}/c as expected at RHIC or LHC). We point out that during such finite QGP lifetime the spectrum of emitted photons carries information on the initial state. There is an inherent ambiguity in separating the virtual from the observable photons during the transient evolution of the QGP. We propose a real time formulation to extract the photon yield which includes the initial stage of formation of the QGP parametrized by an effective time scale of formation Γ−1\Gamma^{-1}. This formulation coincides with the S-matrix approach in the infinite lifetime limit. It allows to separate the virtual cloud as well as the observable photons emitted during the pre- equilibrium stage from the yield during the QGP lifetime. We find that the lowest order contribution O(αem)\mathcal{O}(\alpha_{em}) which does \emph{not} contribute to the S-matrix approach, is of the same order of or larger than the S-matrix contribution during the lifetime of the QGP for a typical formation time ∌1fm/c\sim 1 \mathrm{fm}/c. The yield for momenta ≳3Gev/c\gtrsim 3 \mathrm{Gev}/c features a power law fall-off ∌T3Γ2/k5\sim T^3 \Gamma^2/k^{5} and is larger than that obtained with the S-matrix for momenta ≄4Gev/c\geq 4 \mathrm{Gev}/c. We provide a comprehensive numerical comparison between the real time and S-matrix yields and study the dynamics of the build-up of the photon cloud and the different contributions to the radiative energy loss. The reliability of the current estimates on photon emission is discussed.Comment: 31 pages, 12 eps figures, version to appear in PR
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