Linking project-based production and project management temporary systems in multiple contexts:An introduction to the special edition

As organisations in more and more industries look for flexible ways of production in the wake of rapidly changing market environments, project-based organising is becoming an increasingly important mode of organisation (Eisenhardt & Tabrizi, 1995). Whereas project-based organisation was traditionally mainly the domain of industries such as film making (Sorenson & Waguespack, 2006), theatre (Goodman & Goodman, 1976), and construction (Gann & Salter, 2000), a project-based mode of operation has recently pervaded many other sectors in the economy, including software development, advertising, biotechnology, consulting, emergency response, fashion, television and complex products and systems (Grabher, 2004; Hobday, 2000). This increasing prevalence is reflected in an exponentially growing body of research (Bakker, 2010), which has made marked progress in areas such as project-based learning (Prencipe & Tell, 2001), project-based innovation (Eisenhardt & Tabrizi, 1995) and project-based careers (Jones, 1996). As a consequence, research on project organisation has moved from being a narrow specialty domain toward being a broad research paradigm, attending to a broad audience in organisation science and beyond (Sydow et al., 2004). In a fairly recent review paper, Bakker (2010) shows that in the period 1988–2008 scholarly attention, as indicated by publications in books and ISI-indexed journals, grew exponentially (see Figure 1). Comparing the number of publications in the period 1988-1998 with the period 1998–2008, he observed an increase of almost 340%

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Research design for the South African innovation survey 2001

The University of Pretoria in close cooperation with the Eindhoven University of Technology has decided to conduct a South African Innovation Survey in 2001. The purpose of the survey is twofold; firstly, to get a representative, nationwide picture of the innovative behaviour and performance of South African firms in manufacturing and services, and secondly, to compare the South African situation on innovation to the European one. The South African Innovation Survey will be modelled on the European Community Innovation Survey (CIS) conducted in European Union countries. This paper describes the proposed research design and modifications to the CIS questionnaire to suit the South African environment

Generalized harmonic formulation in spherical symmetry

In this pedagogically structured article, we describe a generalized harmonic formulation of the Einstein equations in spherical symmetry which is regular at the origin. The generalized harmonic approach has attracted significant attention in numerical relativity over the past few years, especially as applied to the problem of binary inspiral and merger. A key issue when using the technique is the choice of the gauge source functions, and recent work has provided several prescriptions for gauge drivers designed to evolve these functions in a controlled way. We numerically investigate the parameter spaces of some of these drivers in the context of fully non-linear collapse of a real, massless scalar field, and determine nearly optimal parameter settings for specific situations. Surprisingly, we find that many of the drivers that perform well in 3+1 calculations that use Cartesian coordinates, are considerably less effective in spherical symmetry, where some of them are, in fact, unstable.Comment: 47 pages, 15 figures. v2: Minor corrections, including 2 added references; journal version

Adaptive Mesh Refinement for Characteristic Grids

I consider techniques for Berger-Oliger adaptive mesh refinement (AMR) when numerically solving partial differential equations with wave-like solutions, using characteristic (double-null) grids. Such AMR algorithms are naturally recursive, and the best-known past Berger-Oliger characteristic AMR algorithm, that of Pretorius & Lehner (J. Comp. Phys. 198 (2004), 10), recurses on individual "diamond" characteristic grid cells. This leads to the use of fine-grained memory management, with individual grid cells kept in 2-dimensional linked lists at each refinement level. This complicates the implementation and adds overhead in both space and time. Here I describe a Berger-Oliger characteristic AMR algorithm which instead recurses on null \emph{slices}. This algorithm is very similar to the usual Cauchy Berger-Oliger algorithm, and uses relatively coarse-grained memory management, allowing entire null slices to be stored in contiguous arrays in memory. The algorithm is very efficient in both space and time. I describe discretizations yielding both 2nd and 4th order global accuracy. My code implementing the algorithm described here is included in the electronic supplementary materials accompanying this paper, and is freely available to other researchers under the terms of the GNU general public license.Comment: 37 pages, 15 figures (40 eps figure files, 8 of them color; all are viewable ok in black-and-white), 1 mpeg movie, uses Springer-Verlag svjour3 document class, includes C++ source code. Changes from v1: revised in response to referee comments: many references added, new figure added to better explain the algorithm, other small changes, C++ code updated to latest versio

Critical Collapse of the Massless Scalar Field in Axisymmetry

We present results from a numerical study of critical gravitational collapse of axisymmetric distributions of massless scalar field energy. We find threshold behavior that can be described by the spherically symmetric critical solution with axisymmetric perturbations. However, we see indications of a growing, non-spherical mode about the spherically symmetric critical solution. The effect of this instability is that the small asymmetry present in what would otherwise be a spherically symmetric self-similar solution grows. This growth continues until a bifurcation occurs and two distinct regions form on the axis, each resembling the spherically symmetric self-similar solution. The existence of a non-spherical unstable mode is in conflict with previous perturbative results, and we therefore discuss whether such a mode exists in the continuum limit, or whether we are instead seeing a marginally stable mode that is rendered unstable by numerical approximation.Comment: 11 pages, 8 figure

Gravitational waves from quasi-spherical black holes

A quasi-spherical approximation scheme, intended to apply to coalescing black holes, allows the waveforms of gravitational radiation to be computed by integrating ordinary differential equations.Comment: 4 revtex pages, 2 eps figure

Numerical Study of Cosmic Censorship in String Theory

Recently Hertog, Horowitz, and Maeda have argued that cosmic censorship can be generically violated in string theory in anti-de Sitter spacetime by considering a collapsing bubble of a scalar field whose mass saturates the Breitenlohner-Freedman bound. We study this system numerically and find that for various choices of initial data black holes form rather than naked singularities, implying that in these cases cosmic censorship is upheld.Comment: 16 pages, latex, 10 figures, uses JHEP.cls, v2: minor changes, version to be published in JHE

Homothetic Self-Similar Solutions of the Three-Dimensional Brans-Dicke Gravity

All homothetic self-similar solutions of the Brans-Dicke scalar field in three-dimensional spacetime with circular symmetry are found in closed form.Comment: latex, five pages, without figur