3,946 research outputs found

    Direct-to-Patient Survey for Diagnosis of Benign Paroxysmal Positional Vertigo

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    Given the high incidence of dizziness and its frequent misdiagnosis, we aim to create a clinical support system to classify the presence or absence of benign paroxysmal positional vertigo with high accuracy and specificity. This paper describes a three-phase study currently underway for classification of benign paroxysmal positional vertigo, which includes diagnosis by a specialist in a clinical setting. Patient background information is collected by a survey on an Android tablet and machine learning techniques are applied for classification. Decision trees and wrappers are employed for their ability to provide information about the question set. One goal of the study is to attain an optimal question set. Each phase of the study presents a unique set and style of questions. Results achieved in the first two phases of the survey indicate that our approach using decision trees with filters or wrappers does a good job of identifying benign paroxysmal positional vertigo

    Guidance applications of a quasi-optimum control technique Final report

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    Quasi-optimal control technique for orbital injection guidanc

    An Asymptotic Expansion and Recursive Inequalities for the Monomer-Dimer Problem

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    Let (lambda_d)(p) be the p monomer-dimer entropy on the d-dimensional integer lattice Z^d, where p in [0,1] is the dimer density. We give upper and lower bounds for (lambda_d)(p) in terms of expressions involving (lambda_(d-1))(q). The upper bound is based on a conjecture claiming that the p monomer-dimer entropy of an infinite subset of Z^d is bounded above by (lambda_d)(p). We compute the first three terms in the formal asymptotic expansion of (lambda_d)(p) in powers of 1/d. We prove that the lower asymptotic matching conjecture is satisfied for (lambda_d)(p).Comment: 15 pages, much more about d=1,2,

    Residential building damage from hurricane storm surge: proposed methodologies to describe, assess and model building damage

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    Although hydrodynamic models are used extensively to quantify the physical hazard of hurricane storm surge, the connection between the physical hazard and its effects on the built environment has not been well addressed. The focus of this dissertation research is the improvement of our understanding of the interaction of hurricane storm surge with the built environment. This is accomplished through proposed methodologies to describe, assess and model residential building damage from hurricane storm surge. Current methods to describe damage from hurricane events rely on the initiating mechanism. To describe hurricane damage to residential buildings, a combined wind and flood damage scale is developed that categorizes hurricane damage on a loss-consistent basis, regardless of the primary damage mechanism. The proposed Wind and Flood (WF) Damage Scale incorporates existing damage and loss assessment methodologies for wind and flood events and describes damage using a seven-category discrete scale. Assessment of hurricane damage has traditionally been conducted through field reconnaissance deployments where damage information is captured and cataloged. The increasing availability of high resolution satellite and aerial imagery in the last few years has led to damage assessments that rely on remotely sensed information. Existing remote sensing damage assessment methodologies are reviewed for high velocity flood events at the regional, neighborhood and per-building levels. The suitability of using remote sensing in assessing residential building damage from hurricane storm surge at the neighborhood and per-building levels is investigated using visual analysis of damage indicators. Existing models for flood damage in the United States generally quantify the economic loss that results from flooding as a function of depth, rather than assessing a level of physical damage. To serve as a first work in this area, a framework for the development of an analytical damage model for residential structures is presented. Input conditions are provided by existing hydrodynamic storm surge models and building performance is determined through a comparison of physical hazard and building resistance parameters in a geospatial computational environment. The proposed damage model consists of a two-tier framework, where overall structural response and the performance of specific components are evaluated

    Phase-locking transition in a chirped superconducting Josephson resonator

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    By coupling a harmonic oscillator to a quantum system it is possible to perform a dispersive measurement that is quantum non-demolition (QND), with minimal backaction. A non-linear oscillator has the advantage of measurement gain, but what is the backaction? Experiments on superconducting quantum bits (qubits) coupled to a non-linear Josephson oscillator have thus far utilized the switching of the oscillator near a dynamical bifurcation for sensitivity, and have demonstrated partial QND measurement. The detailed backaction associated with the switching process is complex, and may ultimately limit the degree to which such a measurement can be QND. Here we demonstrate a new dynamical effect in Josephson oscillators by which the bifurcation can be accessed without switching. When energized with a frequency chirped drive with an amplitude close to a sharp, phase-locking threshold, the oscillator evolves smoothly in one of two diverging trajectories - a pointer for the state of a qubit. The observed critical behavior agrees well with theory and suggests a new modality for quantum state measurement.Comment: 5 pages, 4 figure

    Asymptotic Expansions for lambda_d of the Dimer and Monomer-Dimer Problems

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    In the past few years we have derived asymptotic expansions for lambda_d of the dimer problem and lambda_d(p) of the monomer-dimer problem. The many expansions so far computed are collected herein. We shine a light on results in two dimensions inspired by the work of M. E. Fisher. Much of the work reported here was joint with Shmuel Friedland.Comment: 4 page
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