3,273 research outputs found

    Structural Analysis: Shape Information via Points-To Computation

    Full text link
    This paper introduces a new hybrid memory analysis, Structural Analysis, which combines an expressive shape analysis style abstract domain with efficient and simple points-to style transfer functions. Using data from empirical studies on the runtime heap structures and the programmatic idioms used in modern object-oriented languages we construct a heap analysis with the following characteristics: (1) it can express a rich set of structural, shape, and sharing properties which are not provided by a classic points-to analysis and that are useful for optimization and error detection applications (2) it uses efficient, weakly-updating, set-based transfer functions which enable the analysis to be more robust and scalable than a shape analysis and (3) it can be used as the basis for a scalable interprocedural analysis that produces precise results in practice. The analysis has been implemented for .Net bytecode and using this implementation we evaluate both the runtime cost and the precision of the results on a number of well known benchmarks and real world programs. Our experimental evaluations show that the domain defined in this paper is capable of precisely expressing the majority of the connectivity, shape, and sharing properties that occur in practice and, despite the use of weak updates, the static analysis is able to precisely approximate the ideal results. The analysis is capable of analyzing large real-world programs (over 30K bytecodes) in less than 65 seconds and using less than 130MB of memory. In summary this work presents a new type of memory analysis that advances the state of the art with respect to expressive power, precision, and scalability and represents a new area of study on the relationships between and combination of concepts from shape and points-to analyses

    Stop smoking the Easyway:addiction, self-help and tobacco cessation

    Get PDF
    This article examines Easyway, a popular clinical and self-help method for the treatment of smoking addiction established by the late Allen Carr in 1984. It begins by addressing how smoking has come to be constituted as a neuropharmacological addiction and some of the issues and concerns raised against this in the social sciences. After situating its theoretical and empirical focus, the article then proceeds with an interpretative thematic analysis of a selection of Easyway self-help texts. The aims here are as follows: firstly, to show how Easyway, as a discourse, constitutes the problem of nicotine addiction in novel and distinctive ways; secondly, to elaborate how the Easyway texts seek to govern readers – paradoxically, through their free capacity for reflection, introspection and action – to overcome their situated addiction to smoking; and thirdly, to identify and locate the significance of the author’s implicit claims to charisma in underpinning his authority to know and treat nicotine addiction

    Review of: M. Stuart Madden, Toxic Torts Deskbook

    Get PDF
    M. Stuart Madden, Toxic Torts Deskbook (Lewis Publishers 1992). Acknowledgements, case index, general index, notes, preface. LC 91-48238; ISBN 0- 87371-508-X. [230 pp. Cloth 69.95domestic,69.95 domestic, 84.00 elsewhere. 2000 Corporate Boulevard, NW, Boca Raton FL 33431.]Review of

    Editor\u27s Note

    Get PDF

    Principal Nested Spheres for Time Warped Functional Data Analysis

    Full text link
    There are often two important types of variation in functional data: the horizontal (or phase) variation and the vertical (or amplitude) variation. These two types of variation have been appropriately separated and modeled through a domain warping method (or curve registration) based on the Fisher Rao metric. This paper focuses on the analysis of the horizontal variation, captured by the domain warping functions. The square-root velocity function representation transforms the manifold of the warping functions to a Hilbert sphere. Motivated by recent results on manifold analogs of principal component analysis, we propose to analyze the horizontal variation via a Principal Nested Spheres approach. Compared with earlier approaches, such as approximating tangent plane principal component analysis, this is seen to be the most efficient and interpretable approach to decompose the horizontal variation in some examples

    A scale-based approach to finding effective dimensionality in manifold learning

    Get PDF
    The discovering of low-dimensional manifolds in high-dimensional data is one of the main goals in manifold learning. We propose a new approach to identify the effective dimension (intrinsic dimension) of low-dimensional manifolds. The scale space viewpoint is the key to our approach enabling us to meet the challenge of noisy data. Our approach finds the effective dimensionality of the data over all scale without any prior knowledge. It has better performance compared with other methods especially in the presence of relatively large noise and is computationally efficient.Comment: Published in at http://dx.doi.org/10.1214/07-EJS137 the Electronic Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of Mathematical Statistics (http://www.imstat.org

    PCA consistency in high dimension, low sample size context

    Get PDF
    Principal Component Analysis (PCA) is an important tool of dimension reduction especially when the dimension (or the number of variables) is very high. Asymptotic studies where the sample size is fixed, and the dimension grows [i.e., High Dimension, Low Sample Size (HDLSS)] are becoming increasingly relevant. We investigate the asymptotic behavior of the Principal Component (PC) directions. HDLSS asymptotics are used to study consistency, strong inconsistency and subspace consistency. We show that if the first few eigenvalues of a population covariance matrix are large enough compared to the others, then the corresponding estimated PC directions are consistent or converge to the appropriate subspace (subspace consistency) and most other PC directions are strongly inconsistent. Broad sets of sufficient conditions for each of these cases are specified and the main theorem gives a catalogue of possible combinations. In preparation for these results, we show that the geometric representation of HDLSS data holds under general conditions, which includes a ρ\rho-mixing condition and a broad range of sphericity measures of the covariance matrix.Comment: Published in at http://dx.doi.org/10.1214/09-AOS709 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org
    corecore