126 research outputs found

    Deadlock-freeness of hexagonal systolic arrays

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    With the re-emergence of parallel computation for technical applications in these days also the classical concept of systolic arrays is becoming important again. However, for the sake of their operational safety, the question of deadlock must be addressed. For this contribution we used the well-known Roscoe-Dathi method to demonstrate the deadlock-freeness of a systolic array with hexagonal connectivity. Our result implies that it is theoretically safe to deploy such arrays on various platforms. Our proof is valid for all cases in which the computational pattern (input-output-behaviour) of the array does not depend on the particular values (contents) of the communicated data.http://www.elsevier.com/locate/iplmv201

    Project management maturity and project management success in developing countries

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    This paper explores whether organisations in a developing country have become more mature over time in their project management practices, and compares the current state to findings from a similar study conducted in 2010. It thus contributes to the scant literature on project management maturity in developing countries. Six hundred responses to a project management maturity questionnaire were used to investigate the perceived project management success of 9 389 projects. The results indicated that the perceived average project management maturity dropped from the 2010 value of 2.88 to 2.64 in 2020. Despite this, most of the projects surveyed were still perceived as successful.Hierdie artikel ondersoek of organisasies in ’n ontwikkelde land meer volwasse geword het in hulle projekbestuurspraktyke, en vergelyk die huidige situasie met bevindings in ’n soortgelyke studie wat in 2010 onderneem is. Dit dra dus by tot die skaars literatuur rakende projekbestuurvolwassenheid in onwikkelende lande. Seshonderd terugvoere vir ’n projekbestuursvolwassenheid vraelys is gebruik om die projekbestuursukses van 9 389 projekte te ondersoek. Resultate wys dat die gemiddelde waargenome projekbestuursvolwassenheid gedaal het van 2.88 in 2010 tot 2.64 in 2020. Ten spyte hiervan is die meeste projekte steeds as suksesvol beskou.http://sajie.journals.ac.za/pubam2024Graduate School of Technology Management (GSTM)SDG-09: Industry, innovation and infrastructur

    The role of project manager competence in project management success : the case of a utility company

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    A project manager’s competency depends on the project’s complexity and includes a unique set of personal attributes and the ability to apply appropriate leadership styles. This paper reports on a Delphi study that includes the views of 30 experts – employed by a utility that executes projects with different levels of complexity. The results confirm that project manager competence is influenced by leadership styles that are appropriate for specific project lifecycle stages and levels of project complexity, as well as specific personal attributes. The study thus provides guidance regarding the project manager competence that is required for specific situations.’n Projekbestuurder se vaardighede hang af van projek kompleksiteit en sluit in ’n stel persoonlike eienskappe asook die vermoë om verskillende leierskapstyle te beoefen. Hierdie artikel rapporteer oor ’n Delphi studie wat die menings van 30 kundige praktisyns insluit – almal werknemers van ’n nutsmaatskappy wat projekte met verskillende vlakke van kompleksiteit hanteer. Die resultate bevestig dat die vaardigheid van ’n projekbestuurder beïnvloed word deur leierskapstyle wat toepaslik is vir spesifieke projekfases en vir spesifieke vlakke van projek-kompleksiteit, asook deur bepaalde persoonlike eienskappe. Die studie verskaf dus leiding oor projekbestuurder vaardighede wat benodig word in spesifieke situasies.http://sajie.journals.ac.za/pubam2024Graduate School of Technology Management (GSTM)SDG-09: Industry, innovation and infrastructur

    The SKA Dish SPF and LMC Interaction Design: Interfaces, Simulation, Testing and Integration

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    The Square Kilometre Array (SKA) project is responsible for developing the SKA Observatory, the world's largest radio telescope ever built: eventually two arrays of radio antennas - SKA1-Mid and SKA1-Low - will be installed in the South Africa's Karoo region and Western Australia's Murchison Shire respectively, each covering a different range of radio frequencies. In particular, the SKA1-Mid array will comprise of 133 15m diameter dish antennas observing in the 350 MHz-14 GHz range, each locally managed by a Local Monitoring and Control (LMC) system and remotely orchestrated by the SKA Telescope Manager (TM) system. All control system functionality run on the Tango Controls platform. The Dish Single Pixel Feed (SPF) work element will design the combination of feed elements, orthomode transducers (OMTs), and low noise amplifiers (LNAs) that receive the astronomical radio signals. Some SPFs have cryogenically cooled chambers to obtain the sensitivity requirements. This paper gives a status update of the SKA Dish SPF and LMC interaction design, focusing on SPF, LMC simulators and engineering/operational user interfaces, prototypes being developed and technological choices

    Challenges confronting road freight transport and the use of vehicle-pavement interaction analysis in addressing these challenges

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    Traditional arguments for maintaining riding quality of pavement are expanded in this paper to examine the effects of deteriorating riding quality on vehicle operating costs, freight damage and logistics. The objectives of this paper are to analyse the effects of different levels of riding quality on a truck and its freight, and to discuss potential applications of the analysis in terms of effectiveness of the freight transport system. The paper discusses needs and drivers influencing freight transport costs, vehicle-pavement interaction concepts, and the potential physical effects and costs from roads with deteriorating riding quality. A case study is presented analysing vehicle-pavement interaction for selected roadways in California. It is concluded that investments in pavement and freight transport industry improvements can be investigated by applying vehicle-pavement interaction analysis to evaluate damage to pavement, vehicle and freight that would result from alternative levels of pavement riding quality. The paper recommends that existing concepts, tools and resources such as dedicated truck lanes and vehicle-pavement interaction analysis can help to improve the freight transport system. A framework is proposed to better understand the scale of potential impacts of riding quality from localised effects to larger-scale influences, including costs to customers and global competitiveness.Caltranshttp://www.journals.co.za/ej/ejour_civileng.htm

    Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

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    The elliptic, v2v_2, triangular, v3v_3, and quadrangular, v4v_4, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range η<0.8|\eta|<0.8 at different collision centralities and as a function of transverse momentum, pTp_{\rm T}, out to pT=20p_{\rm T}=20 GeV/cc. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for pT>8p_{\rm T}>8 GeV/cc. The small pTp_{\rm T} dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to pT=8p_{\rm T}=8 GeV/cc. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least pT=8p_{\rm T}=8 GeV/cc indicating that the particle type dependence persists out to high pTp_{\rm T}.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186

    Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

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    The inclusive transverse momentum (pTp_{\rm T}) distributions of primary charged particles are measured in the pseudo-rapidity range η<0.8|\eta|<0.8 as a function of event centrality in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}}=2.76 TeV with ALICE at the LHC. The data are presented in the pTp_{\rm T} range 0.15<pT<500.15<p_{\rm T}<50 GeV/cc for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor RAAR_{\rm{AA}} using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pTp_{\rm T} particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with RAA0.13R_{\rm{AA}}\approx0.13 at pT=6p_{\rm T}=6-7 GeV/cc. Above pT=7p_{\rm T}=7 GeV/cc, there is a significant rise in the nuclear modification factor, which reaches RAA0.4R_{\rm{AA}} \approx0.4 for pT>30p_{\rm T}>30 GeV/cc. In peripheral collisions (70-80%), the suppression is weaker with RAA0.7R_{\rm{AA}} \approx 0.7 almost independently of pTp_{\rm T}. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284

    Measurement of charm production at central rapidity in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV

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    The pTp_{\rm T}-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D0^0, D+^+, and D+^{*+} in the rapidity range y<0.5|y|<0.5, and for transverse momentum 1<pT<121< p_{\rm T} <12 GeV/cc, were measured in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D0^0 \rightarrow Kπ\pi, D+^+ \rightarrow Kππ\pi\pi, D+^{*+} \rightarrow D0π^0\pi, and their charge conjugates, and was performed on a Lint=1.1L_{\rm int} = 1.1 nb1^{-1} event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at s=2.76\sqrt{s} = 2.76 TeV and at 7 TeV was evaluated by extrapolating to the full phase space the pTp_{\rm T}-differential production cross sections at s=2.76\sqrt{s} = 2.76 TeV and our previous measurements at s=7\sqrt{s} = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/307

    Particle-yield modification in jet-like azimuthal di-hadron correlations in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    The yield of charged particles associated with high-pTp_{\rm T} trigger particles (8<pT<158 < p_{\rm T} < 15 GeV/cc) is measured with the ALICE detector in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV relative to proton-proton collisions at the same energy. The conditional per-trigger yields are extracted from the narrow jet-like correlation peaks in azimuthal di-hadron correlations. In the 5% most central collisions, we observe that the yield of associated charged particles with transverse momenta pT>3p_{\rm T}> 3 GeV/cc on the away-side drops to about 60% of that observed in pp collisions, while on the near-side a moderate enhancement of 20-30% is found.Comment: 15 pages, 2 captioned figures, 1 table, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/350

    Centrality Dependence Of The Pseudorapidity Density Distribution For Charged Particles In Pb-pb Collisions At √snn=2.76tev

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