3,085 research outputs found

    Explaining coronary heart disease trends in Hong Kong: creation of a model for policy and planning.

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    1. The largest contribution of coronary heart disease (CHD) mortality reductions was from medical treatment. 2. A smaller contribution was estimated to be due to risk factors changes. 3. Improvement of treatment uptake levels can have a substantial effect in reducing CHD mortality.published_or_final_versio

    Pattern recognition in a multi-sensor environment

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    Journal ArticleCurrent pattern recognition systems tend to operate on a single sensor, e.g., a camera. however. the need is now evident for pattern recognition systems which can operate in multi-sensor environments. For example, a robotics workstation may use range finders. cameras, tactile pads, etc. The Multi-sensor Kernel System (MKS) provides an efficient and coherent approach to the specification, recovery, and analysis of patterns in the data sensed by such a diverse set of sensors. We demonstrate how much a system can be used to support both feature-based object models as well as structural models. The problems solved is the localization of a three-dimensional object in 3-space. Moreover, MKS allows rapid reconfiguration of the available sensors and the high-level models

    Some experiments with the 3-D hough shape transform

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    Journal ArticleThe application of the Hough shape transform to the problem of the identification and localization of objects in 3-space is presented. The rotation-invariant Hough transform is defined which permits the determination of the geometric transformation from the model to the detected object. Given a sample of 3-D surface points, a set of special model points are derived which are used to form the model. Methods are presented for reducing the amount of computation and accumulator space requited to perform the analysis

    When to rebuild or when to adjust scorecards

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    Data-based scorecards, such as those used in credit scoring, age with time and need to be rebuilt or readjusted. Unlike the huge literature on modelling the replacement and maintenance of equipment there have been hardly any models that deal with this problem for scorecards. This paper identifies an effective way of describing the predictive ability of the scorecard and from this describes a simple model for how its predictive ability will develop. Using a dynamic programming approach one is then able to find when it is optimal to rebuild and when to readjust a scorecard. Failing to readjust or rebuild a scorecard when they aged was one of the defects in credit scoring identified in the investigations into the sub-prime mortgage crisis

    Ecosystem complexity on the Kerguelen Axis: the need for integrated ecosystem studies and sustained coordinated monitoring

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    第6回極域科学シンポジウム[OB] 極域生物圏11月16日(月) 統計数理研究所 セミナー室1(D305

    Stress testing credit card portfolios: an application in South Africa

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    Motivated by a real problem, this study aims to develop models to conduct stress testing on credit card portfolios. Two modelling approaches were extended to include the impact of lenders’ actions within the model. The first approach was a regression model of the aggregate losses based on economic variables with autocorrelations of the errors. The second approach was a set of vintage-level models that highlighted the months-on-book effect on credit losses. A case study using the models was described using South African credit card data. In this case, the models were used to stress test the credit card portfolio under several economic scenarios

    Dissipationless conductance in a topological coaxial cable

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    We present a dynamical mechanism leading to dissipationless conductance, whose quantized value is controllable in a (3+1)-dimensional electronic system. The mechanism is exemplified by a theory of Weyl fermions coupled to a Higgs field, also known as an axion insulator. We show that the insertion of an axial gauge flux can induce vortex lines in the Higgs field, similar to the development of vortices in a superconductor upon the insertion of magnetic flux. We further show that the necessary axial gauge flux can be generated using Rashba spin-orbit coupling or a magnetic field. Vortex lines in the Higgs field are known to bind chiral fermionic modes, each of which serves as a one-way channel for electric charge with conductance e²/h. Combining these elements, we present a physical picture, the “topological coaxial cable,” illustrating how the value of the quantized conductance could be controlled in such an axion insulator.National Science Foundation (U.S.) (DGE-1247312)United States. Department of Energy (DEF-06ER46316

    Design of a continuous-wave tunable terahertz source using waveguide-phase-matched GaAs

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    A novel source of continuous-wave terahertz radiation based on difference frequency generation (DFG) in GaAs crystal is proposed. Phase matching is provided using integration of appropriate optical and terahertz waveguides based on dispersive properties of GaAs. The output frequency can be tuned between 0–3.5 THz by tuning the incident wavelengths in the range of 1.5–1.6 µm
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