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Publications

Publications by CTM

2022

Design and Experimental Evaluation of a Bluetooth 5.1 Antenna Array for Angle-of-Arrival Estimation

Authors
Paulino, N; Pessoa, LM; Branquinho, A; Gonçalves, E;

Publication
13th International Symposium on Communication Systems, Networks and Digital Signal Processing, CSNDSP 2022, Porto, Portugal, July 20-22, 2022

Abstract
One the of the applications in the realm of the Internet-of-Things (IoT) is real-time localization of assets in specific application environments where satellite based global positioning is unviable. Numerous approaches for localization relying on wireless sensor mesh systems have been evaluated, but the recent Bluetooth Low Energy (BLE) 5.1 direction finding features based on Angle-of-Arrival (AoA) promise a low-cost solution for this application. In this paper, we present an implementation of a BLE 5.1 based circular antenna array, and perform two experimental evaluations over the quality of the retrieved data sampled from the array. Specifically, we retrieve samples of the phase value of the Constant Tone Extension which enables the direction finding functionalities through calculation of phase differences between antenna pairs. We evaluate the quality of the sampled phase data in an anechoic chamber, and in a real-world environment using a setup composed of four BLE beacons. © 2022 IEEE.

2022

Optimizing Packet Reception Rates for Low Duty-Cycle BLE Relay Nodes

Authors
Paulino, N; Pessoa, LM; Branquinho, A; Almeida, R; Ferreira, I;

Publication
IEEE SENSORS JOURNAL

Abstract
In order to achieve the full potential of the Internet-of-Things, connectivity between devices should be ubiquitous and efficient. Wireless mesh networks are a critical component to achieve this ubiquitous connectivity for a wide range of services, and are composed of terminal devices (i.e., nodes), such as sensors of various types, and wall powered gateway devices, which provide further internet connectivity (e.g., via Wi-Fi). When considering large indoor areas, such as hospitals or industrial scenarios, the mesh must cover a large area, which introduces concerns regarding range and the number of gateways needed and respective wall cabling infrastructure, including data and power. Solutions for mesh networks implemented over different wireless protocols exist, like the recent Bluetooth Low Energy (BLE) 5.1. While BLE provides lower power consumption, some wall-power infrastructure may still be required. Alternatively, if some nodes are battery powered, concerns such as lifetime and packet delivery are introduced. We evaluate a scenario where the intermediate nodes of the mesh are battery powered, using a BLE relay of our own design, which acts as a range extender by forwarding packets from end-nodes to gateways. We present the relay's design and experimentally determine the packet forwarding efficiency for several scenarios and configurations. In the best case, up to 35% of the packets transmitted by 11 end-nodes can be forwarded to a gateway by a single relay under continuous operation. A battery lifetime of 1 year can be achieved with a relay duty cycle of 20%.

2022

BacalhauNet: A tiny CNN for lightning-fast modulation classification

Authors
Jose Rosa; Daniel Granhao; Guilherme Carvalho; Tiago Gon?alves; Monica Figueiredo; Luis Conde Bento; Nuno Paulino; Luis M. Pessoa;

Publication
ITU Journal on Future and Evolving Technologies

Abstract
Deep learning methods have been shown to be competitive solutions for modulation classification tasks, but suffer from being computationally expensive, limiting their use on embedded devices. We propose a new deep neural network architecture which employs known structures, depth-wise separable convolution and residual connections, as well as a compression methodology, which combined lead to a tiny and fast algorithm for modulation classification. Our compressed model won the first place in ITU's AI/ML in 5G Challenge 2021, achieving 61.73? compression over the challenge baseline and being over 2.6? better than the second best submission. The source code of this work is publicly available at github.com/ITU-AI- ML-in-5G-Challenge/ITU-ML5G-PS-007-BacalhauNet.

2022

A Batch of Integer Data Sets for Clustering Algorithms

Authors
Paulino, N;

Publication

Abstract

2022

A Dataset of Phase Samples using an 8-Element Uniform Circular Antenna Array and a Bluetooth Low Energy 5.1 Nordic nRF52811 Based Receiver

Authors
Paulino, N;

Publication

Abstract

2022

Acting emotions: physiological correlates of emotional valence and arousal dynamics in theatre

Authors
Aly, L; Bota, P; Godinho, L; Bernardes, G; Silva, H;

Publication
IMX 2022 - Proceedings of the 2022 ACM International Conference on Interactive Media Experiences

Abstract
Professional theatre actors are highly specialized in controlling their own expressive behaviour and non-verbal emotional expressiveness, so they are of particular interest in fields of study such as affective computing. We present Acting Emotions, an experimental protocol to investigate the physiological correlates of emotional valence and arousal within professional theatre actors. Ultimately, our protocol examines the physiological agreement of valence and arousal amongst several actors. Our main contribution lies in the open selection of the emotional set by the participants, based on a set of four categorical emotions, which are self-assessed at the end of each experiment. The experiment protocol was validated by analyzing the inter-rater agreement (> 0.261 arousal, > 0.560 valence), the continuous annotation trajectories, and comparing the box plots for different emotion categories. Results show that the participants successfully induced the expected emotion set to a significant statistical level of distinct valence and arousal distributions. © 2022 Owner/Author.

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