22,550 research outputs found

    Visual and computational analysis of structure-activity relationships in high-throughput screening data

    Get PDF
    Novel analytic methods are required to assimilate the large volumes of structural and bioassay data generated by combinatorial chemistry and high-throughput screening programmes in the pharmaceutical and agrochemical industries. This paper reviews recent work in visualisation and data mining that can be used to develop structure-activity relationships from such chemical/biological datasets

    Construction of embedded fMRI resting state functional connectivity networks using manifold learning

    Full text link
    We construct embedded functional connectivity networks (FCN) from benchmark resting-state functional magnetic resonance imaging (rsfMRI) data acquired from patients with schizophrenia and healthy controls based on linear and nonlinear manifold learning algorithms, namely, Multidimensional Scaling (MDS), Isometric Feature Mapping (ISOMAP) and Diffusion Maps. Furthermore, based on key global graph-theoretical properties of the embedded FCN, we compare their classification potential using machine learning techniques. We also assess the performance of two metrics that are widely used for the construction of FCN from fMRI, namely the Euclidean distance and the lagged cross-correlation metric. We show that the FCN constructed with Diffusion Maps and the lagged cross-correlation metric outperform the other combinations

    Non-profit Health Care Services Marketing: Persuasive Messages Based on Multidimensional Concept Mapping and Direct Magnitude Estimation

    Get PDF
    Persuasive messages for marketing healthcare services in general and coordinated care in particular are more important now for providers, hospitals, and third-party payers than ever before. The combination of measurement based information with creativity may be among the most critical factors in reaching markets or expanding markets. The research presented here provides an approach to marketing coordinated care services which allows healthcare managers to plan persuasive messages given the market conditions they face. Using market respondents’ thinking about product attributes combined with distance measurement between pairs of product attributes, a conceptual marketing map is presented and applied to advertising, message copy, and delivery. The data reported here are representative of the potential caregivers for which the messages are intended. Results are described with implications for application to coordinated care services. Theory building and marketing practice are discussed in the light of findings and methodology

    Tensor Numerical Methods in Quantum Chemistry: from Hartree-Fock Energy to Excited States

    Get PDF
    We resume the recent successes of the grid-based tensor numerical methods and discuss their prospects in real-space electronic structure calculations. These methods, based on the low-rank representation of the multidimensional functions and integral operators, led to entirely grid-based tensor-structured 3D Hartree-Fock eigenvalue solver. It benefits from tensor calculation of the core Hamiltonian and two-electron integrals (TEI) in O(nlogn)O(n\log n) complexity using the rank-structured approximation of basis functions, electron densities and convolution integral operators all represented on 3D n×n×nn\times n\times n Cartesian grids. The algorithm for calculating TEI tensor in a form of the Cholesky decomposition is based on multiple factorizations using algebraic 1D ``density fitting`` scheme. The basis functions are not restricted to separable Gaussians, since the analytical integration is substituted by high-precision tensor-structured numerical quadratures. The tensor approaches to post-Hartree-Fock calculations for the MP2 energy correction and for the Bethe-Salpeter excited states, based on using low-rank factorizations and the reduced basis method, were recently introduced. Another direction is related to the recent attempts to develop a tensor-based Hartree-Fock numerical scheme for finite lattice-structured systems, where one of the numerical challenges is the summation of electrostatic potentials of a large number of nuclei. The 3D grid-based tensor method for calculation of a potential sum on a L×L×LL\times L\times L lattice manifests the linear in LL computational work, O(L)O(L), instead of the usual O(L3logL)O(L^3 \log L) scaling by the Ewald-type approaches

    Euclidean Distance Matrices: Essential Theory, Algorithms and Applications

    Get PDF
    Euclidean distance matrices (EDM) are matrices of squared distances between points. The definition is deceivingly simple: thanks to their many useful properties they have found applications in psychometrics, crystallography, machine learning, wireless sensor networks, acoustics, and more. Despite the usefulness of EDMs, they seem to be insufficiently known in the signal processing community. Our goal is to rectify this mishap in a concise tutorial. We review the fundamental properties of EDMs, such as rank or (non)definiteness. We show how various EDM properties can be used to design algorithms for completing and denoising distance data. Along the way, we demonstrate applications to microphone position calibration, ultrasound tomography, room reconstruction from echoes and phase retrieval. By spelling out the essential algorithms, we hope to fast-track the readers in applying EDMs to their own problems. Matlab code for all the described algorithms, and to generate the figures in the paper, is available online. Finally, we suggest directions for further research.Comment: - 17 pages, 12 figures, to appear in IEEE Signal Processing Magazine - change of title in the last revisio
    corecore