General Dynamics

About: General Dynamics is a company organization based out in Fairfax, Virginia, United States. It is known for research contribution in the topics: Signal & Propellant. The organization has 5722 authors who have published 5819 publications receiving 85768 citations. The organization is also known as: GD & General Dynamics Corporation.

Fuzzy min-max neural networks

Abstract: A supervised neural network classifier using a combination of min-max hyperboxes and fuzzy logic is described A min-max hyperbox and its membership function define a fuzzy set Each class in the neural network is a collection of labeled hyperboxes (fuzzy sets) The degree to which an input pattern belongs to a class is determined by the membership function of the winning hyperbox Using multiple hyperbox fuzzy sets to form classes allows arbitrary numbers and shapes of classes and their respective class boundaries The min-max classification learning procedure requires only a single pass through the data and allows online learning The author describes how the fuzzy min-max classifier is implemented as a neural network, explains how min-max classes are produced, and provides two examples of operation >

Plasma wave echo.

Abstract: It is shown that if a longitudinal wave is excited in a collision-free plasma and Landaudamps away, and a second wave is excited and also damps away, then a third wave (i.e., the echo) will spontaneously appear in the plasma.

Solar concentrator array

Abstract: A solar concentrator panel having an array of off axis cylindrical parabolic mirrors with an optical design of relatively short focal length solar cells arranged in line that converts sunlight to electricity. The back surface of the mirrors are used as the solar cell mount and the heat sink for the adjacent mirror. By appropriate positioning of the adjacent mirror so that the focal line of the parabola falls within the boundary or rim of the mirror reflected solar light can be directed to the solar cell mounted on the back of the adjacent mirror and converted to electricity

A Bayesian Approach to Multiple Target Detection and Tracking

Abstract: This paper considers the problem of simultaneously detecting and tracking multiple targets. The problem can be formulated in a Bayesian framework and solved, in principle, by computation of the joint multitarget probability density (JMPD). In practice, exact computation of the JMPD is impossible, and the predominant challenge is to arrive at a computationally tractable approximation. A particle filtering scheme is developed for this purpose in which each particle is a hypothesis on the number of targets present and the states of those targets. The importance density for the particle filter is designed in such a way that the measurements can guide sampling of both the target number and the target states. Simulation results, with measurements generated from real target trajectories, demonstrate the ability of the proposed procedure to simultaneously detect and track ten targets with a reasonable sample size

County-Level COVID-19 Vaccination Coverage and Social Vulnerability - United States, December 14, 2020-March 1, 2021.

Abstract: The U.S. COVID-19 vaccination program began in December 2020, and ensuring equitable COVID-19 vaccine access remains a national priority.* COVID-19 has disproportionately affected racial/ethnic minority groups and those who are economically and socially disadvantaged (1,2). Thus, achieving not just vaccine equality (i.e., similar allocation of vaccine supply proportional to its population across jurisdictions) but equity (i.e., preferential access and administra-tion to those who have been most affected by COVID-19 disease) is an important goal. The CDC social vulnerability index (SVI) uses 15 indicators grouped into four themes that comprise an overall SVI measure, resulting in 20 metrics, each of which has national and state-specific county rankings. The 20 metric-specific rankings were each divided into lowest to highest tertiles to categorize counties as low, moderate, or high social vulnerability counties. These tertiles were combined with vaccine administration data for 49,264,338 U.S. residents in 49 states and the District of Columbia (DC) who received at least one COVID-19 vaccine dose during December 14, 2020-March 1, 2021. Nationally, for the overall SVI measure, vaccination coverage was higher (15.8%) in low social vulnerability counties than in high social vulnerability counties (13.9%), with the largest coverage disparity in the socioeconomic status theme (2.5 percentage points higher coverage in low than in high vulnerability counties). Wide state variations in equity across SVI metrics were found. Whereas in the majority of states, vaccination coverage was higher in low vulnerability counties, some states had equitable coverage at the county level. CDC, state, and local jurisdictions should continue to monitor vaccination coverage by SVI metrics to focus public health interventions to achieve equitable coverage with COVID-19 vaccine.