5,282 research outputs found

    On and Off-diagonal Sturmian operator: dynamic and spectral dimension

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    We study two versions of quasicrystal model, both subcases of Jacobi matrices. For Off-diagonal model, we show an upper bound of dynamical exponent and the norm of the transfer matrix. We apply this result to the Off-diagonal Fibonacci Hamiltonian and obtain a sub-ballistic bound for coupling large enough. In diagonal case, we improve previous lower bounds on the fractal box-counting dimension of the spectrum.Comment: arXiv admin note: text overlap with arXiv:math-ph/0502044 and arXiv:0807.3024 by other author

    Generalized Solutions for Quantum Mechanical Oscillator on K\"{a}hler Conifold

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    We study the possible generalized boundary conditions and the corresponding solutions for the quantum mechanical oscillator model on K\"{a}hler conifold. We perform it by self-adjoint extension of the the initial domain of the effective radial Hamiltonian. Remarkable effect of this generalized boundary condition is that at certain boundary condition the orbital angular momentum degeneracy is restored! We also recover the known spectrum in our formulation, which of course correspond to some other boundary condition.Comment: 7 pages, latex, no figur

    The Human Capital “Impact” on E-Business: The Case of Encyclopedia Britannica

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    [Excerpt] The term “New Economy” has been coined to describe the remarkable economic performance of the 1990s. Stiroh, (1999) an economist at the Federal Reserve Bank of New York observes that its defining characteristic is a “focus on increasing globalization and expanding information technology” (pg. 87). Research suggests that revenues from electronic based business to business trade will double over the next five years from 43billionin1998to43 billion in 1998 to 1.3 trillion in 2003. Revenues from business to consumer trade are predicted to rise from 8billionto8 billion to 108 billion over the same time period (Forrester Research, 1998). However, there is increasing attention to the challenges facing business in the new economy, and an increasing chorus of analysts suggesting how tenuous many of these business models really are. A recent Barron’s article showed that many dot-com companies have only days of remaining cash (Willoughby, March 20, 1999). Such a key emerging phenomenon has not escaped the attention of writers, though the existing body of writing has some important gaps. We would classify existing e-business literature into two groups. First, there is a growing body of literature that discusses the how the Internet is transforming business models and organizational strategies. A second, much smaller body of work has focused on e-HR, or more specifically, the implications of the Internet on various HR practices

    Understanding voice, distribution and listening in Digital Storytelling

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    This article interrogates the commissioning, production and distribution of Digital Storytelling made through collaborations between academics, practitioners and community groups. In this context, Digital Storytelling is defined as a workshop-based process where participants gain the skills and knowledge needed to tell a personal story using their own words and imagery. It starts with a recognition that the development of new forms of media activity enabled by digitalization have led directly to new modes of community-based media which, in turn, have created spaces for practitioners that emphasize the importance of the voice of the participant. Couldry’s (2010) three concepts of voice are used here to interrogate Digital Storytelling, namely opportunities for new voices to speak and be heard, an increased mutual awareness flowing from a greater influence over distribution and exhibition and the potential for new intensities of listening as a means to explore the notion that digitalization increased the range and number of voices across the media. The article argues that the relatively modest ambitions of many Digital Storytelling projects mean that complex issues are either resolved or sidestepped on a pragmatic, case-by-case basis and, because of this, the work is undertheorized and often poorly understood. Processes of institutional mediation within Digital Storytelling bring into question the reliability of Digital Storytelling as a data source and too often condemn Digital Storytelling to modest outcomes

    Analysis of unbounded operators and random motion

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    We study infinite weighted graphs with view to \textquotedblleft limits at infinity,\textquotedblright or boundaries at infinity. Examples of such weighted graphs arise in infinite (in practice, that means \textquotedblleft very\textquotedblright large) networks of resistors, or in statistical mechanics models for classical or quantum systems. But more generally our analysis includes reproducing kernel Hilbert spaces and associated operators on them. If XX is some infinite set of vertices or nodes, in applications the essential ingredient going into the definition is a reproducing kernel Hilbert space; it measures the differences of functions on XX evaluated on pairs of points in XX. And the Hilbert norm-squared in H(X)\mathcal{H}(X) will represent a suitable measure of energy. Associated unbounded operators will define a notion or dissipation, it can be a graph Laplacian, or a more abstract unbounded Hermitian operator defined from the reproducing kernel Hilbert space under study. We prove that there are two closed subspaces in reproducing kernel Hilbert space H(X)\mathcal{H}(X) which measure quantitative notions of limits at infinity in XX, one generalizes finite-energy harmonic functions in H(X)\mathcal{H}(X), and the other a deficiency index of a natural operator in H(X)\mathcal{H}(X) associated directly with the diffusion. We establish these results in the abstract, and we offer examples and applications. Our results are related to, but different from, potential theoretic notions of \textquotedblleft boundaries\textquotedblright in more standard random walk models. Comparisons are made.Comment: 38 pages, 4 tables, 3 figure
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