As a result of the increasing usage of UAVs (Unmanned Air Vehicles) in urban environments for UAM (Urban Air Mobility) applications, the preciseness and reliability of PNT (Positioning, Navigation and Timing) systems have critical importance for mission safety and success. With its high accuracy and global coverage, GNSS (Global Navigation Satellite System) is the primary PNT source for UAM applications. However, GNSS is highly vulnerable to Non-Line-of-Sight (NLoS) blockages and multipath (MP) reflections, which are quite common, especially in urban areas. This study proposes a machine learning-based NLoS/MP detection and exclusion algorithm using GNSS observables to enhance position estimations at the receiver level. By using the ensemble machine learning algorithm with the proposed method, overall 93.2% NLoS/MP detection accuracy was obtained, and 29.8% accuracy enhancement was achieved by excluding these detected signals.1 Graduate student, School of Aerospace, Transport and Manufacturing (SATM) 2 PhD candidate, School of Aerospace, Transport and Manufacturing (SATM) 3 Senior Lecturer, Centre for Autonomous and Cyberphysical Systems

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Background: Biphalangealism has been evaluated in many studies and has been shown as a common variant. Its frequency varies according to the populations. This epidemiological study aimed to determine the prevalence of biphalangealism for each toe in the Turkish population and compare it with other populations. Methods: The local hospital radiological database was searched for all consecutive foot radiographs, obtained between 2014 and 2018. Anteroposterior (AP) and oblique radiographs obtained to evaluate trauma or foot pathologies were included. Two-phalangeal toes according to radiographical views were defined as biphalangeal and other three-phalangeal toes were defined as normal. Results: A total of 2,881 radiographs of 2,710 adult patients met the incusion criteria. There were 1,558 (57.5%) female and 1,152 (42.5%) male patients. The cases were unilateral in 2,539 patients and bilateral in 171 patients. The overall prevalence of biphalangeal third toe was 0.29%, fourth toe was 1.29%, and fifth toe was 23.3%. Conclusions: The presence of pedal biphalangealism is a common variant and its frequency varies according to the populations. The exact cause is still unclear. Further studies are required to assess the clinical impact of biphalangealism.

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