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1. Cooperative Speech Separation With a Microphone Array and Asynchronous Wearable Devices

   https://doi.org/10.21437/Interspeech.2022-11025  

   Corey, Ryan; Mittal, Manan; Sarkar, Kanad; Singer, Andrew C. (September 2022, Proc. Interspeech 2022)

   We consider the problem of separating speech from several talkers in background noise using a fixed microphone array and a set of wearable devices. Wearable devices can provide reliable information about speech from their wearers, but they typically cannot be used directly for multichannel source separation due to network delay, sample rate offsets, and relative motion. Instead, the wearable microphone signals are used to compute the speech presence probability for each talker at each time-frequency index. Those parameters, which are robust against small sample rate offsets and relative motion, are used to track the second-order statistics of the speech sources and background noise. The fixed array then separates the speech signals using an adaptive linear time-varying multichannel Wiener filter. The proposed method is demonstrated using real-room recordings from three human talkers with binaural earbud microphones and an eight-microphone tabletop array. 

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2. How Does a Plant Cell Build a New Cell Wall When Dividing?

   https://doi.org/10.3389/frym.2021.570769  

   Chang, Mingqin; Drakakaki, Georgia (June 2021, Frontiers for Young Minds)

   null (Ed.)

   If you live in an apartment or a house, you will notice that your home has different rooms separated by walls. A plant is just like your home, except there are many small rooms, called cells. Plant cells, like rooms, are also separated by cell walls. Cell walls are unique and are not found in animal cells. In a building, if you want to turn one large room into two small rooms, you build a new wall to divide it. This is similar to how a plant cell divides into two cells during cell division. To build a wall in a building, you need to employ construction workers, design the building plan, buy building materials, and finally assembly the wall. How does the plant cell take care of these different jobs? This article explains how the cell wall is built in a plant cell during cell division. 

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3. A High-Gain Observer Approach to Robust Trajectory Estimation and Tracking for a Multirotor Unmanned Aerial Vehicle

   https://doi.org/10.1115/1.4065758  

   Boss, Connor J; Srivastava, Vaibhav (January 2025, Journal of Dynamic Systems, Measurement, and Control)

   Abstract Using the context of trajectory estimation and tracking for multirotor unmanned aerial vehicles (UAVs), we explore the challenges in applying high-gain observers to highly dynamic systems. The multirotor will operate in the presence of external disturbances and modeling errors. At the same time, the reference trajectory is unknown and generated from a reference system with unknown or partially known dynamics. We assume the only measurements that are available are the position and orientation of the multirotor and the position of the reference system. We adopt an extended high-gain observer (EHGO) estimation framework to estimate the unmeasured multirotor states, modeling errors, external disturbances, and the reference trajectory. We design a robust output feedback controller for trajectory tracking that comprises a feedback linearizing controller and the EHGO. The proposed control method is rigorously analyzed to establish its stability properties. Finally, we illustrate our theoretical results through numerical simulation and experimental validation in which a multirotor tracks a moving ground vehicle with an unknown trajectory and dynamics and successfully lands on the vehicle while in motion. 

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4. Ferro-electret nanogenerators as flexible microphones

   https://doi.org/10.1109/SENSORS43011.2019.8956772  

   Dsouza, Henry; Wheeler, Joshua; Sepulveda, Nelson (January 2020, IEEE Sensors Conference)

   Research on flexible transducers capable of sensing acoustic signals has become increasingly important due to its implications in human interfaces with wearable electronics. The proof-of-concept for a flexible microphone/loudspeaker based on the use of a ferro-electret nanogenerator (FENG) was recently presented. Following that, this work characterizes FENG-based microphones, showing the sensitivity of a 5 cm x 5 cm, single layer FENG to be ∼ .015 mV/Pa. The variance of sensitivity based on surface area is also studied and presented. Polar patterns or directivity is emphasized in this work by studying how various shapes (i.e. flat, concave and convex) affect the output. The spectral information of the output of FENGbased microphone to typical voice input is compared with a commercially available microphone 

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5. How swarming bats can use the collective soundscape for obstacle avoidance

   https://doi.org/10.1371/journal.pcbi.1013013  

   Vanderelst, Dieter; Peremans, Herbert (May 2025, PLOS Computational Biology)

   Marshall, James AR (Ed.)

   Some echolocating bats, such asTadarida brasiliensis, fly in groups when emerging from or entering caves. In large, dense swarms, distinguishing self-generated echoes from the multitude of calls and echoes produced by others presents a significant challenge – akin to a cocktail party nightmare. While spectral jamming responses have been proposed as a solution, this mechanism is unlikely to be effective in such conditions. Here, we propose an alternative hypothesis: rather than isolating their own echoes, bats might navigate by relying on the local amplitude gradient of the collective soundscape. To test this, we developed an agent-based simulation of bats flying through corridors, demonstrating that they can avoid obstacles, including other bats and corridor walls, without distinguishing individual echoes. Our findings suggest that in dense swarms, bats can exploit the emergent acoustic environment to maintain safe distances. The current paper also suggests shifting the perspective on jamming itself. Rather than framing overlapping signals solely as a source of interference, our findings highlight that these signals can also carry useful information, reframing the problem from conflict to cooperative signal processing. 

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