United States Department of the Army

About: United States Department of the Army is a government organization based out in Arlington, Virginia, United States. It is known for research contribution in the topics: Poison control & Population. The organization has 32668 authors who have published 42453 publications receiving 947075 citations. The organization is also known as: DA & U.S. Department of the Army.

Isometric, isotonic, and isokinetic torque variations in four muscle groups through a range of joint motion.

Abstract: The purpose of this investigation was to describe and examine variations in maximal torque produced by knee extension, knee flexion, elbow extension, and elbow flexion through a range of joint motion. Subjects were young, healthy men (n = 16) and women (n = 15). Torque was measured isometrically and isokinetically using a modified Cybex apparatus. Isotonic torque was calculated from a one-repetition maximum using a modified N-K device. Joint angles were monitored with an electrogoniometer. Torque-joint angle curves were constructed for both men and women for each muscle group. Isometric torque was highest, followed by isotonic and isokinetic torque. Torque declined with increasing isokinetic velocity. The angle of peak torque was found to be highly variable in individual subjects. Variations in torque curves were explained in terms of mechanical characteristics of the musculoskeletal system. Muscle group capability was generally found to be well matched to the mechanical requirements of the movement.

Adaptive real-time pattern recognition using a liquid crystal TV based joint transform correlator

Abstract: Recently, many applications of the liquid crystal television (LCTV) to real-time signal processing have been reported. A basic description of the application of the LCTV to realtime pattern recognition was first reported by Liu et al. Gregory later also showed a successful space-invariant correlation using a LCTV as a spatial light modulator. Both methods were based on the use of a complex matched (VanderLugt) spatial filter. The joint transform architecture is an alternative approach to optical pattern recognition. The joint transform method has proved to be suitable for adaptive programmable correlation because no matched spatial filter is required. The reference pattern may simply be generated by a computer and input to a low space-bandwidth product (SBP), electronically addressed, spatial light modulator. Conversely, it is very difficult to generate a dynamic matched spatial filter in the Fourier plane. A microcomputer-based programmable optical correlator using a magnetooptical device (MOD) and a liquid crystal light valve (LCLV) was proposed recently by Yu and Ludman. In this Letter, a new implementation of the real-time joint transform correlator architecture using inexpensive LCTVs will be discussed. Preliminary experimental results are presented to verify the usefulness of the technique. There are three major objections to using commercially available liquid crystal TVs for optical processing applications: (1) low contrast ratio, (2) phase nonuniformity, and (3) low resolution and low SBP. These problems must be minimized if a LCTV is to be used as a spatial light modulator in a coherent optical system. The contrast uniformity