Vitor Manuel Filipe

Abstract

Abstract
The capability of drones to perform autonomous missions has led retail companies to use them for deliveries, saving time and human resources. In these services, the delivery depends on the Global Positioning System (GPS) to define an approximate landing point. However, the landscape can interfere with the satellite signal (e.g., tall buildings), reducing the accuracy of this approach. Changes in the environment can also invalidate the security of a previously defined landing site (e.g., irregular terrain, swimming pool). Therefore, the main goal of this work is to improve the process of goods delivery using drones, focusing on the detection of the potential receiver. We developed a solution that has been improved along its iterative assessment composed of five test scenarios. The built prototype complements the GPS through Computer Vision (CV) algorithms, based on Convolutional Neural Networks (CNN), running in a Raspberry Pi 3 with a Pi NoIR Camera (i.e., No InfraRed-without infrared filter). The experiments were performed with the models Single Shot Detector (SSD) MobileNet-V2, and SSDLite-MobileNet-V2. The best results were obtained in the afternoon, with the SSDLite architecture, for distances and heights between 2.5-10 m, with recalls from 59%-76%. The results confirm that a low computing power and cost-effective system can perform aerial human detection, estimating the landing position without an additional visual marker.

Abstract
The recovery of walking function following spinal cord injury (SCI) is of major importance to patients and clinicians. In experimental SCI studies, a rat model is widely used to assess walking function, following thoracic spinal cord lesion. In an effort to provide a resource which investigators can refer to when seeking the most appropriate functional assay, the authors have compiled and categorized the behavioral assessments used to measure the deficits and recovery of the gait in thoracic SCI rats. These categories include kinematic and kinetic measurements. Within this categorization, we discuss the advantages and disadvantages of each type of measurement. The present review includes the type of outcome data that they produce, the technical difficulty and the time required to potentially train the animals to perform them, and the need for expensive or highly specialized equipment. The use of multiple kinematic and kinetic parameters is recommended to identify subtle deficits and processes involved in the compensatory mechanisms of walking function after experimental thoracic SCI in rats. © 2019 Elsevier Ltd

Abstract

Abstract
The overall objective of this work is to review the assistive technologies that have been proposed by researchers in recent years to address the limitations in user mobility posed by visual impairment. This work presents an “umbrella review.” Visually impaired people often want more than just information about their location and often need to relate their current location to the features existing in the surrounding environment. Extensive research has been dedicated into building assistive systems. Assistive systems for human navigation, in general, aim to allow their users to safely and efficiently navigate in unfamiliar environments by dynamically planning the path based on the user’s location, respecting the constraints posed by their special needs. Modern mobile assistive technologies are becoming more discrete and include a wide range of mobile computerized devices, including ubiquitous technologies such as mobile phones. Technology can be used to determine the user’s location, his relation to the surroundings (context), generate navigation instructions and deliver all this information to the blind user. © 2017 Springer-Verlag GmbH Germany