800 research outputs found

    Requirements for IT Governance in Organizations Experiencing Decentralization

    No full text
    International audienceDecentralization of organizations and subsequent change of their management and operation styles require changes in organization's processes and heavily involve IT. Enterprise Architecture (EA) frameworks fit to primarily centralized organizational structures, and as such have shortcomings when used in decentralized organizations. We illustrate this idea on the example of one organization in the Higher Education sector that faces decentralization of its structure and has to adapt to it. Overcoming these challenges requires some new principles to be introduced and incorporated into the EA knowledge. In particular for IT governance, in this study we argue that peer-to-peer principles can offer more suitable governance over current EA frameworks as they are able to better align with decentralized components of an organizational structure

    The ins and outs of participation in a weather information system

    Get PDF
    In this paper our aim is to show even though access to technology, information or data holds the potential for improved participation, participation is wired into a larger network of actors, artefacts and information practices. We draw on a case study of a weather information system developed and implemented by a non-profit organisation to both describe the configuration of participation, but also critically assess inclusion and exclusion. We present a set of four questions - a basic, practical toolkit - by which we together with the organisation made sense of and evaluated participation in the system

    Improved limits on the coupling of ultralight bosonic dark matter to photons from optical atomic clock comparisons

    Full text link
    We present improved constraints on the coupling of ultralight bosonic dark matter to photons based on long-term measurements of two optical frequency ratios. In these optical clock comparisons, we relate the frequency of the 2S1/2(F=0)2F7/2(F=3){}^2S_{1/2} (F=0)\leftrightarrow {}^2F_{7/2} (F=3) electric-octupole (E3) transition in 171^{171}Yb+^{+} to that of the 2S1/2(F=0)2D3/2(F=2){}^2S_{1/2} (F=0)\leftrightarrow \,{}^2D_{3/2} (F=2) electric-quadrupole (E2) transition of the same ion, and to that of the 1S03P0{}^1S_0\leftrightarrow\,{}^3P_0 transition in 87^{87}Sr. Measurements of the first frequency ratio νE3/νE2\nu_\textrm{E3}/\nu_\textrm{E2} are performed via interleaved interrogation of both transitions in a single ion. The comparison of the single-ion clock based on the E3 transition with a strontium optical lattice clock yields the second frequency ratio νE3/νSr\nu_\textrm{E3}/\nu_\textrm{Sr}. By constraining oscillations of the fine-structure constant α\alpha with these measurement results, we improve existing bounds on the scalar coupling ded_e of ultralight dark matter to photons for dark matter masses in the range of about 10241017eV/c2 10^{-24}-10^{-17}\,\textrm{eV}/c^2. These results constitute an improvement by more than an order of magnitude over previous investigations for most of this range. We also use the repeated measurements of νE3/νE2\nu_\textrm{E3}/\nu_\textrm{E2} to improve existing limits on a linear temporal drift of α\alpha and its coupling to gravity.Comment: 7 pages, 5 figure

    Eigenvector localization as a tool to study small communities in online social networks

    Full text link
    We present and discuss a mathematical procedure for identification of small "communities" or segments within large bipartite networks. The procedure is based on spectral analysis of the matrix encoding network structure. The principal tool here is localization of eigenvectors of the matrix, by means of which the relevant network segments become visible. We exemplified our approach by analyzing the data related to product reviewing on Amazon.com. We found several segments, a kind of hybrid communities of densely interlinked reviewers and products, which we were able to meaningfully interpret in terms of the type and thematic categorization of reviewed items. The method provides a complementary approach to other ways of community detection, typically aiming at identification of large network modules

    Manipulation and removal of defects in spontaneous optical patterns

    Full text link
    Defects play an important role in a number of fields dealing with ordered structures. They are often described in terms of their topology, mutual interaction and their statistical characteristics. We demonstrate theoretically and experimentally the possibility of an active manipulation and removal of defects. We focus on the spontaneous formation of two-dimensional spatial structures in a nonlinear optical system, a liquid crystal light valve under single optical feedback. With increasing distance from threshold, the spontaneously formed hexagonal pattern becomes disordered and contains several defects. A scheme based on Fourier filtering allows us to remove defects and to restore spatial order. Starting without control, the controlled area is progressively expanded, such that defects are swept out of the active area.Comment: 4 pages, 4 figure
    corecore