16,345 research outputs found

    First principles of project management - A review and commentary on Max Wideman's paper

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    The following thoughtful commentary on the original paper "First Principles of Project Management" presented on this site in November 2000, makes interesting reading and useful suggestions for improvement. Many of the comments derive from work done in preparing the authors' paper "The Underlying Theory of Project Management is Obsolete" presented to the Project Management's Research Conference in 200

    The instability of a viscous sheet floating on an air cushion

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    The dynamics of a thin sheet of viscous liquid levitating on an air cushion is studied. Experimentally, it is observed that, after an initial settling stage, a local disturbance grows, eventually leading to the sheet blowing up like a viscous balloon. We derive a dynamical model for the levitating sheet and propose a mechanism for the onset of the instability. This instability is driven by the local drainage of the sheet due to a growing disturbance on its lower surface and is moderated by surface tension, the bending stiffness of the sheet and advection in the air layer. The balance between these effects determines the most unstable wavelength and this is illustrated by some numerical simulations

    Fringe Science: Defringing CCD Images with Neon Lamp Flat Fields

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    Fringing in CCD images is troublesome from the aspect of photometric quality and image flatness in the final reduced product. Additionally, defringing during calibration requires the inefficient use of time during the night to collect and produce a "supersky" fringe frame. The fringe pattern observed in a CCD image for a given near-IR filter is dominated by small thickness variations across the detector with a second order effect caused by the wavelength extent of the emission lines within the bandpass which produce the interference pattern. We show that essentially any set of emission lines which generally match the wavelength coverage of the night sky emission lines within a bandpass will produce an identical fringe pattern. We present an easy, inexpensive, and efficient method which uses a neon lamp as a flat field source and produces high S/N fringe frames to use for defringing an image during the calibration process.Comment: accepted to PAS

    Public Opinion in Perspective: Wisconsin's Mind on Education

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    Outlines survey findings on Wisconsin residents' views on the quality of public schools and reforms including increased spending, accountability, vouchers, charter schools, online education, and merit pay, compared with Milwaukee and national surveys

    Miniaturized pointing mount performance analysis

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    Analytical analysis and computer simulation results of the miniaturized pointing mount as an instrument pointing system are presented. Miniaturized mount performance results include inertial pointing, slewing, tracking, and rastering. Typical instrument characteristics are used as well as some parameter variations of instrument and miniaturized pointing mount characteristics

    Contracts and production

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    It is argued that a change in the prevailing theory of production is also influencing how contracts, especially in construction, are being conceived. It is contended that the theoretical shift in question, both in production and contracting, concerns the metaphysical presuppositions of respective theories. This claim is further justified through a critical analysis of how risks and collaboration between parties are considered in conventional contracting
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