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Creators/Authors contains: "Ellis, Cameron"

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  1. Unmanned aerial vehicles (UAVs) have witnessed widespread adoption in the modern world, with their development set to continue into the future. As UAV technology and applications advance, it becomes imperative to understand their communication capabilities. UAVs experience distinct radio propagation conditions compared to ground-based radio nodes, necessitating a critical investigation into aerial radio node performance. This paper analyzes interference in UAV-to-UAV (U2U) communications within drone corridors and proposes an interference mitigation strategy utilizing millimeter wave (mmWave) beamforming. Employing a semi-persistent scheduling approach from the Third Generation Partnership Project (3GPP) sidelink communications for low altitude aerial nodes in drone corridors, the study primarily examines interference from drone clusters within designated air corridors. To assess U2U communication performance, a 3GPP standard-compliant cross-layer simulator is developed. Simulation results demonstrate that employing mmWave beamforming instead of isotropic transmission substantially reduces interference, leading to higher communications reliability and enabling more UAVs to occupy and communicate in the airspace. 
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  2. Jbabdi, Saad (Ed.)
    The extent to which brain functions are localized or distributed is a foundational question in neuroscience. In the human brain, common fMRI methods such as cluster correction, atlas parcellation, and anatomical searchlight are biased by design toward finding localized representations. Here we introduce the functional searchlight approach as an alternative to anatomical searchlight analysis, the most commonly used exploratory multivariate fMRI technique. Functional searchlight removes any anatomical bias by grouping voxels based only on functional similarity and ignoring anatomical proximity. We report evidence that visual and auditory features from deep neural networks and semantic features from a natural language processing model, as well as object representations, are more widely distributed across the brain than previously acknowledged and that functional searchlight can improve model-based similarity and decoding accuracy. This approach provides a new way to evaluate and constrain computational models with brain activity and pushes our understanding of human brain function further along the spectrum from strict modularity toward distributed representation. 
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  3. Functional magnetic resonance imaging (fMRI) offers a rich source of data for studying the neural basis of cognition. Here, we describe the Brain Imaging Analysis Kit (BrainIAK), an open-source, free Python package that provides computationally optimized solutions to key problems in advanced fMRI analysis. A variety of techniques are presently included in BrainIAK: intersubject correlation (ISC) and intersubject functional connectivity (ISFC), functional alignment via the shared response model (SRM), full correlation matrix analysis (FCMA), a Bayesian version of representational similarity analysis (BRSA), event segmentation using hidden Markov models, topographic factor analysis (TFA), inverted encoding models (IEMs), an fMRI data simulator that uses noise characteristics from real data (fmrisim), and some emerging methods. These techniques have been optimized to leverage the efficiencies of high-performance compute (HPC) clusters, and the same code can be seamlessly transferred from a laptop to a cluster. For each of the aforementioned techniques, we describe the data analysis problem that the technique is meant to solve and how it solves that problem; we also include an example Jupyter notebook for each technique and an annotated bibliography of papers that have used and/or described that technique. In addition to the sections describing various analysis techniques in BrainIAK, we have included sections describing the future applications of BrainIAK to real-time fMRI, tutorials that we have developed and shared online to facilitate learning the techniques in BrainIAK, computational innovations in BrainIAK, and how to contribute to BrainIAK. We hope that this manuscript helps readers to understand how BrainIAK might be useful in their research. 
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