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The Impact of Video Compression on Remote Cardiac Pulse Measurement Using Imaging Photoplethysmography

Remote physiological measurement technique leverages digital cameras to recover the blood volume pulse from the human body

Remote measurement of physiological signals has a number of advantages over traditional contact methods. It allows the measurement of vital signals unobtrusively and concomitantly. In recent years, a number of approaches for imaging-based measurement of physiology using digital cameras have been proposed. Imaging photoplethysmography (iPPG) captures variations in light reflected from the body due to blood volume changes in microvascular tissue. It has been demonstrated that sub-pixel variations in color channel measurements from a digital single lens reflex (DSLR) camera, when aggregated, could be used to recover the blood volume pulse. Subsequently, it was shown that iPPG methods can allow accurate measurement of heart rate, heart rate variability, breathing rate, blood oxygenation and pulse transit time.

Posted in: Briefs, Aerospace, Test & Measurement
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Scaling LiDAR Optical Payloads from Drones to Miniature UAVs

The recent surge in demand for adaptive cruise control (ACC) and commercial autonomous vehicles has drawn a lot of attention to these innovative applications. Based on pulsed laser diodes and hybrid receivers with Avalanche Photodiodes (APDs) for laser range finding (LRF), these systems are often classified under the general acronym LiDAR (Light Detection and Ranging).

Posted in: Articles, Aerospace
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Subjective Mapping of Dust-Emission Sources by Using MODIS Imagery

Accurate dust-source characterizations are critical for effectively modeling dust storms and their associated hazards.

Dust storms (5 to 100 km across) often originate from multiple dust-emission sources (1 to 10 km across). Remote-sensing-based dust-source identification is a challenge. A previous study developed a subjective approach for mapping dust sources by using enhanced MODIS satellite imagery; therefore, this study conducted mapping exercises to assess the reproducibility of this technique amongst multiple analysts and in different regions.

Posted in: Briefs, Aerospace, Test & Measurement
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Quality and Validation of Digital Designs for Aerospace and Defense

As aerospace and defense manufacturing becomes increasingly digitized—from the earliest design stages to the factory floor and beyond—data accuracy is fundamental to realizing the speed, quality and repeatability promised by interconnected and automated computer systems and manufacturing machines.

Posted in: Articles, Aerospace
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Custom Data Logger for Real-Time Remote Field Data Collections

Compact, energy efficient instruments have the same functionality as a personal computer.

The U.S. Army Corps of Engineers (USACE), CHL, FRF, had a need for a remote real-time data collection system to control instruments and log and communicate data from five observing stations in the Currituck Sound Estuary, NC1. These stations, referred to as the Currituck Sound Array (CSA), collect a suite of meteorological and oceano-graphic data including wind, air temperature, humidity, incoming solar radiation (above and below water), waves, currents, water level, salinity, and water temperature, as well as turbidity and many other water quality parameters. This array of instruments has a variety of control commands, sample routines, and output data formats. Additionally, the CSA was designed to act as a natural laboratory for estuarine research and as an instrument and model test bed. These capabilities required a reliable and flexible system that would allow easy modification of sampling schemes, the ability to log as many as 15 instruments with a single logger, and allow the incorporation of additional and novel instrumentation with minimal effort and expense.

Posted in: Briefs, Aerospace, Test & Measurement
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Initial Validation of Ballistic Shock Accelerometers

A Test Operations Procedure (TOP) describing methods and instrumentation used in the initial validation of accelerometers to be used in both Ballistic Shock testing and crew/vehicle survivability Live Fire Test and Evaluation (LFT&E).

Method 522.2 of MIL-STD-810G CN1 defines ballistic shock as “a high-level shock that generally results from the impact of projectiles or ordnance on armored combat vehicles”. Typical engagements of interest also include Kinetic Energy projectiles, land mines, and improvised explosive devices. For the purposes of this TOP, ballistic shock is generally referred to as the sudden high-rate loading resulting from under body blast (UBB) testing designed to assess the crew-survivability of military vehicles. Historical testing conducted in both areas have proven the relative similarities between the two environments.

Posted in: Briefs, Aerospace, Sensors
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Test System Ensures Flawless Performance of Military RF Devices

Communication on the battlefield is a life-or-death matter. You can't take chances with RF devices or power units malfunctioning or failing. A soldier's life may depend on how well you designed and tested your product. Will it function in temperature extremes, after physical shocks, and with low battery power? Where will it break or fail, and why? How can that be prevented?

Posted in: Articles, Aerospace
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Using Sintered Fiber Metal Composites for Aircraft Acoustic Attenuation

Sintered fiber metal composites are used in aircraft as an acoustic media within environmental ducting, inlet and exhaust systems. The material can be engineered to meet specific acoustic attenuation and noise reduction goals within these applications. Sintered metal fiber composites have proven reliable and effective since the 1950's, but continue to deliver new value through ongoing investment and new use cases.

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Topology Control in Aerial Multi-Beam Directional Networks

Comparing the performance of a centralized algorithm that retains robust connectivity and reduced throughput to a distributed algorithm that offers higher throughput but fewer network nodes.

In multi-beam directional networks, nodes are able to simultaneously transmit to all neighbors or receive from all neighbors. This spatial reuse allows for high throughputs, but in dense networks can cause significant interference. Topology control (i.e., selecting a subset of neighbors to communicate with) is vital to reduce the interference. Good topology control balances the number of links utilized to achieve fewer collisions while maintaining robust network connectivity.

Posted in: Briefs, Aerospace, Test & Measurement
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Using Thermal Simulation to Model the Effects of Wind on the Mars Curiosity Rover

The Centro de Astrobiología (CAB), a joint center of Consejo Superior de Investigaciones Cientificas and the Instituto Nacional de Tecnica Aeroespacíal (CSIC-INTA), designed and built the weather monitoring station contributed by the Spanish government as part of the payload of the Mars Science Laboratory (MSL) rover, Curiosity, which landed on Mars in August 2012 (Figure 1).

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