714 research outputs found
Power spectrum analysis of staggered quadriphase-shift-keyed signals
Mathematical analysis of power spectrum of outputs from high-reliability communication system is used to determine system bandwidth. Analysis provides mathematical relationships of signal power spectrum at output of hard limiter for any type of baseband pulse input subjected only to output parameter constraints
Frequencies and modes for shells of revolution (FAMSOR)
Using stiffness matrix and lumped-mass representation specified number of natural frequencies are obtained using inverse iteration method. Mode shapes for each frequency are also obtained. These frequencies and mode shapes can be found in reasonable periods of computer time utilizing this code
Nonlinear maximum likelihood estimation of autoregressive time series
Includes bibliographical references.In this paper, we describe an algorithm for finding the exact, nonlinear, maximum likelihood (ML) estimators for the parameters of an autoregressive time series. We demonstrate that the ML normal equations can be written as an interdependent set of cubic and quadratic equations in the AR polynomial coefficients. We present an algorithm that algebraically solves this set of nonlinear equations for low-order problems. For high-order problems, we describe iterative algorithms for obtaining a ML solution.This work was supported by Bonneville Power Administration under Contract #DEBI7990BPO7346 and by the Office of Naval Research, Statistics and Probability Branch, under Contract N00014-89-J-1070
Adaptive subspace detectors
Includes bibliographical references.In this paper, we use the theory of generalized likelihood ratio tests (GLRTs) to adapt the matched subspace detectors (MSDs) of [1] and [2] to unknown noise covariance matrices. In so doing, we produce adaptive MSDs that may be applied to signal detection for radar, sonar, and data communication. We call the resulting detectors adaptive subspace detectors (ASDs). These include Kelly's GLRT and the adaptive cosine estimator (ACE) of [6] and [19] for scenarios in which the scaling of the test data may deviate from that of the training data. We then present a unified analysis of the statistical behavior of the entire class of ASDs, obtaining statistically identical decompositions in which each ASD is simply decomposed into the nonadaptive matched filter, the nonadaptive cosine or t-statistic, and three other statistically independent random variables that account for the performance-degrading effects of limited training data.This work was supported by the Office of Naval Research under Contracts N00014-89-J-1070 and N00014-00-1-0033, and by the National Science Foundation under Contracts MIP-9529050 and ECS 9979400
Stochastic nonlinear differential equation generating 1/f noise
Starting from the simple point process model of 1/f noise we derive a
stochastic nonlinear differential equation for the signal exhibiting 1/f noise
in any desirably wide range of frequency. A stochastic differential equation
(the general Langevin equation with a multiplicative noise) that gives 1/f
noise is derived for the first time. The solution of the equation exhibits the
power-law distribution. The process with 1/f noise is demonstrated by the
numerical solution of the derived equation with the appropriate restriction of
the diffusion of the signal in some finite interval.Comment: 3 figure
Obesity Acceptance: Body Positivity and Clinical Risk Factors
Most people are aware of how they look and, whether poor or positive, have an opinion about their image. Social media influencers, pressure from societal norms, media images, and even friends and family can impact body image. Body positivity has undoubtedly gone mainstream. Included in this movement are obesity acceptance and its demarginalization. However, the acceptance of overweight and obesity may undermine the decades-long progress made toward reducing risk factors for cardiovascular disease (CVD). Obesity is a global epidemic disease with risk factors that include hypertension, inflammation, heart attack, stroke, and diabetes. Obesity is also associated with obstructive sleep apnea. Positive body image is an important component of overall health. However, also maintaining a proper clinical definition and self-perception of what constitutes “normal” weight, coupled with weight management, regular exercise, and monitoring blood pressure and blood sugar, will continue progress toward reducing the risk of cardiovascular disease
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