Ridge count thresholding to uncover coordinated networks during onset of the Covid-19 pandemic.

In order to combat information operations (IO) and disinformation campaigns, one must look at the behaviors of the accounts pushing specific narratives and stories through social media, not at the content itself. In this work, we present a new process for extracting tweet storms and uncovering networks of accounts that are working in a coordinated fashion using ridge count thresholding (RCT). To do this, we started with a dataset of 60 million individual tweets from the early weeks of the Covid-19 pandemic.

Automatic counting of birds in a bird deterrence field trial.

Decreasing costs in high-quality digital cameras, image processing, and digital storage allow researchers to generate and store massive amounts of digital imagery. The time needed to manually analyze these images will always be a limiting factor for experimental design and analysis. Implementation of computer vision algorithms for automating the detection and counting of animals reduces the manpower needed to analyze field images.

Demonstration of a length limited parametric array.

We describe a series of measurements to assess the practicality of a length limited parametric array in air. This study shows that the length limited effect is a measurable phenomenon that can be produced using pairs of commercial off the shelf parametric array speakers. We generated the effect using parametric arrays mounted so that two directional audio beams were simultaneously co-propagating through the open air.

A sonic net excludes birds from an airfield: implications for reducing bird strike and crop losses.

Collisions between birds and aircraft cause billions of dollars of damages annually to civil, commercial, and military aviation. Yet technology to reduce bird strike is not generally effective, especially over longer time periods. Previous information from our lab indicated that filling an area with acoustic noise, which masks important communication channels for birds, can displace European Starlings (Sturnus vulgaris) from food sources.

Classification of flaw severity using pattern recognition for guided wave-based structural health monitoring.

In this paper, the authors present a formal classification routine to characterize flaw severity in an aircraft-grade aluminum plate using Lamb waves. A rounded rectangle flat-bottom hole is incrementally introduced into the plate, and at each depth multi-mode Lamb wave signals are collected to study the changes in received signal due to mode conversion and scattering from the flaw. Lamb wave tomography reconstructions are used to locate and size the flaw at each depth, however information about the severity of the flaw is obscured when the flaw becomes severe enough that scattering effects dominate.