87,069 research outputs found

    The Impact of ICT on Economic Sectors

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    As the author could not find a reassuring mathematical and statistical method in the literature for studying the effect of information communication technologyon enterprises, the author suggested a new research andanalysis method that he also used to study the Hungarian economic sectors. The question of what factors have an effecton their net income is vital for enterprises. The highest increment of specific Gross Value Added was produced by thefields of ‘Manufacturing’, ‘Electricity, gas and water supply’,‘Transport, storage and communication’ and ‘Financialintermediation’. With the exception of ‘Electricity, gas andwater supply’, the other economic sectors belong to the groupof underdeveloped branches (below 50%).On the other hand, ‘Construction’, ‘Health and social work’and‘Hotels and restaurants’ can be seen as laggards, so theygot into the lower left part of the coordinate system.‘Agriculture, hunting and forestry’ can also be classified as alaggard economic sector, but as the effect of the compoundindicator on the increment of Gross Value Added was lesssignificant, it can be found in the upper left part of thecoordinate system. Drawing a trend line on the points, it can bemade clear that it shows a positive gradient, that is, the higherthe usage of ICT devices, the higher improvement can bedetected in the specific Gross Value Added

    Least Squares Ranking on Graphs

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    Given a set of alternatives to be ranked, and some pairwise comparison data, ranking is a least squares computation on a graph. The vertices are the alternatives, and the edge values comprise the comparison data. The basic idea is very simple and old: come up with values on vertices such that their differences match the given edge data. Since an exact match will usually be impossible, one settles for matching in a least squares sense. This formulation was first described by Leake in 1976 for rankingfootball teams and appears as an example in Professor Gilbert Strang's classic linear algebra textbook. If one is willing to look into the residual a little further, then the problem really comes alive, as shown effectively by the remarkable recent paper of Jiang et al. With or without this twist, the humble least squares problem on graphs has far-reaching connections with many current areas ofresearch. These connections are to theoretical computer science (spectral graph theory, and multilevel methods for graph Laplacian systems); numerical analysis (algebraic multigrid, and finite element exterior calculus); other mathematics (Hodge decomposition, and random clique complexes); and applications (arbitrage, and ranking of sports teams). Not all of these connections are explored in this paper, but many are. The underlying ideas are easy to explain, requiring only the four fundamental subspaces from elementary linear algebra. One of our aims is to explain these basic ideas and connections, to get researchers in many fields interested in this topic. Another aim is to use our numerical experiments for guidance on selecting methods and exposing the need for further development.Comment: Added missing references, comparison of linear solvers overhauled, conclusion section added, some new figures adde

    Open TURNS: An industrial software for uncertainty quantification in simulation

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    The needs to assess robust performances for complex systems and to answer tighter regulatory processes (security, safety, environmental control, and health impacts, etc.) have led to the emergence of a new industrial simulation challenge: to take uncertainties into account when dealing with complex numerical simulation frameworks. Therefore, a generic methodology has emerged from the joint effort of several industrial companies and academic institutions. EDF R&D, Airbus Group and Phimeca Engineering started a collaboration at the beginning of 2005, joined by IMACS in 2014, for the development of an Open Source software platform dedicated to uncertainty propagation by probabilistic methods, named OpenTURNS for Open source Treatment of Uncertainty, Risk 'N Statistics. OpenTURNS addresses the specific industrial challenges attached to uncertainties, which are transparency, genericity, modularity and multi-accessibility. This paper focuses on OpenTURNS and presents its main features: openTURNS is an open source software under the LGPL license, that presents itself as a C++ library and a Python TUI, and which works under Linux and Windows environment. All the methodological tools are described in the different sections of this paper: uncertainty quantification, uncertainty propagation, sensitivity analysis and metamodeling. A section also explains the generic wrappers way to link openTURNS to any external code. The paper illustrates as much as possible the methodological tools on an educational example that simulates the height of a river and compares it to the height of a dyke that protects industrial facilities. At last, it gives an overview of the main developments planned for the next few years

    How polycentric is a monocentric city? The role of agglomeration economies

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    Can the demise of the monocentric economy across cities during the 20th century be explained by decreasing transport costs to the city center or are other fundamental forces at work? Taking a hybrid perspective of classical bid-rent theory and a world where clustering of economic activity is driven by (knowledge) spillovers, Berlin, Germany, from 1890 to 1936 serves as a case in point. We assess the extent to which firms in an environment of decreasing transport costs and industrial transformation face a trade-off between distance to the CBD and land rents and how agglomeration economies come into play in shaping their location decisions. Our results suggest that an observable flattening of the traditional distance to the CBD gradient may mask the emergence of significant agglomeration economies, especially within predominantly service-based inner city districts.Transport Innovations; Land Values; Location Productivity; Agglomeration Economies; Economic History; Berlin

    How Polycentric is a Monocentric City? The Role of Agglomeration Economies

    Get PDF
    Can the demise of the monocentric economy across cities during the 20th century be explained by decreasing transport costs to the city center or are other fundamental forces at work? Taking a hybrid perspec¬tive of classical bid-rent theory and a world where clustering of economic activity is driven by (knowledge) spillovers, Berlin, Germany, from 1890 to 1936 serves as a case in point. We assess the extent to which firms in an environment of decreasing transport costs and industrial transformation face a trade-off between distance to the CBD and land rents and how agglomeration economies come into play in shaping their location deci¬sions. Our results suggest that an observable flattening of the traditional distance to the CBD gradient may mask the emergence of significant agglomeration economies, especially within predominantly service-based inner city districts.Transport Innovations, Land Values, Location Productivity, Agglomeration Economies, Economic History, Berlin.
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