3,471 research outputs found

    Quantitative Analysis of Fault and Failure Using Software Metrics

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    It is very complex to write programs that behave accurately in the program verification tools. Automatic mining techniques suffer from 902013;99% false positive rates, because manual specification writing is not easy. Because they can help with program testing, optimization, refactoring, documentation, and most importantly, debugging and repair. To concentrate on this problem, we propose to augment a temporal-property miner by incorporating code quality metrics. We measure code quality by extracting additional information from the software engineering process, and using information from code that is more probable to be correct as well as code that is less probable to be correct. When used as a preprocessing step for an existing specification miner, our technique identifies which input is most suggestive of correct program behaviour, which allows off-the-shelf techniques to learn the same number of specifications using only 45% of their original input

    Investigation of environmental perturbations on passive asymmetric satellite

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    The effects of environmental perturbations on the attitude of a slow tumbling earth-oriented satellite are investigated. The environmental perturbations considered were aerodynamic drag, gravity-gradient, solar radiation pressure, and magnetic torques. The Euler attitude equations were solved numerically for the Skylab spacecraft. Results are presented for both torque-free motion and for cases in which aerodynamic and gravity-gradient torques are acting in a slow tumble mode. Simulations show gravity-gradient effects on satellite momentum to be cyclic and to increase the precession rate of the angular momentum vector about the radius vector. This also tends to align the minor axis along the radius vector. Aerodynamic drag initially decreases angular momentum, slowly precesses the momentum vector about the radius vector, and finally drives the satellite into an unstable mode. Combined gravity-gradient and aerodynamic torques reduce angular momentum and energy, and induce a steady precession rate of the momentum vector about the radius vector

    Multi-Satellite Attitude Prediction program/Orbiting Solar Observatory-8 (MSAP/OSO-8) operating guide

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    The sun's lower corona and chromosphere and their interaction in the X-ray and ultraviolet (UV) spectral regions were investigated to better understand the transport of energy from the photosphere to the corona. The interaction between the solar electromagnetic and particle radiation and the earth's environment was studied and the background component of cosmic X-rays was discussed

    The Berry-Keating Hamiltonian and the Local Riemann Hypothesis

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    The local Riemann hypothesis states that the zeros of the Mellin transform of a harmonic-oscillator eigenfunction (on a real or p-adic configuration space) have real part 1/2. For the real case, we show that the imaginary parts of these zeros are the eigenvalues of the Berry-Keating hamiltonian H=(xp+px)/2 projected onto the subspace of oscillator eigenfunctions of lower level. This gives a spectral proof of the local Riemann hypothesis for the reals, in the spirit of the Hilbert-Polya conjecture. The p-adic case is also discussed.Comment: 9 pages, no figures; v2 included more mathematical background, v3 has minor edits for clarit

    Computations in non-commutative Iwasawa theory

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    We study special values of L-functions of elliptic curves over Q twisted by Artin representations that factor through a false Tate curve extension Q(μp,mp)/QQ(\mu_p^\infty,\sqrt[p^\infty]{m})/Q. In this setting, we explain how to compute L-functions and the corresponding Iwasawa-theoretic invariants of non-abelian twists of elliptic curves. Our results provide both theoretical and computational evidence for the main conjecture of non-commutative Iwasawa theory.Comment: 60 pages; with appendix by John Coates and Ramdorai Sujath

    Modelling gravity on a hyper-cubic lattice

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    We present an elegant and simple dynamical model of symmetric, non-degenerate (n x n) matrices of fixed signature defined on a n-dimensional hyper-cubic lattice with nearest-neighbor interactions. We show how this model is related to General Relativity, and discuss multiple ways in which it can be useful for studying gravity, both classical and quantum. In particular, we show that the dynamics of the model when all matrices are close to the identity corresponds exactly to a finite-difference discretization of weak-field gravity in harmonic gauge. We also show that the action which defines the full dynamics of the model corresponds to the Einstein-Hilbert action to leading order in the lattice spacing, and use this observation to define a lattice analogue of the Ricci scalar and Einstein tensor. Finally, we perform a mean-field analysis of the statistical mechanics of this model.Comment: 5 page

    Leveraging ERP Implementation to Create Intellectual Capital: the Role of Organizational Learning Capability

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    The extent to which enterprise resource planning (ERP) systems deliver value for organizations has been debated. In this study, we argue that the presence of appropriate organizational resources is essential for capturing the potential of ERP implementation. We investigate the relationship between ERP implementation and two organizational resources, specifically, Intellectual Capital (IC) and Organizational Learning Capability (OLC) to enrich the understanding of the way the value of ERP implementations can be realized. A sample of 226 manufacturing firms in Vietnam was surveyed to test the theoretical model. Structural equation modelling with partial least square method and two approaches for moderation analysis were used to analyze the data. The results indicate that ERP implementation scope has a positive impact on intellectual capital (IC). However, firms need to build a certain level of OLC to utilize ERP implementation for the enhancement of IC

    K-Rational D-Brane Crystals

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    In this paper the problem of constructing spacetime from string theory is addressed in the context of D-brane physics. It is suggested that the knowledge of discrete configurations of D-branes is sufficient to reconstruct the motivic building blocks of certain Calabi-Yau varieties. The collections of D-branes involved have algebraic base points, leading to the notion of K-arithmetic D-crystals for algebraic number fields K. This idea can be tested for D0-branes in the framework of toroidal compactifications via the conjectures of Birch and Swinnerton-Dyer. For the special class of D0-crystals of Heegner type these conjectures can be interpreted as formulae that relate the canonical Neron-Tate height of the base points of the D-crystals to special values of the motivic L-function at the central point. In simple cases the knowledge of the D-crystals of Heegner type suffices to uniquely determine the geometry.Comment: 36 page
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