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Publicações

Publicações por CTM

2017

Analysis of Loop Antenna with Ground Plane for Underwater Communications

Autores
Aboderin, O; Pessoa, LM; Salgado, HM;

Publicação
OCEANS 2017 - ABERDEEN

Abstract
Transmission and reception of high-speed short range signal is important for successful underwater water communications between an Autonomous Underwater Vehicle (AUV) or Remote Operated Vehicles (ROVs) and a docking station or underwater sensor nodes during a survey mission. The need for this form of application is currently receiving global attention from scientific groups and industries. Hence, underwater antennas are therefore required to provide these links and achieve good data rates and propagation distances for these applications either in fresh or sea water scenario. In this paper, the performance of loop antenna placed at a specified distance and parallel to the ground plane is assessed through simulation for usage in fresh water and operating in the High Frequency (HF) band. Three variations of this antenna namely; the circular loop, the square loop and the delta loop antennas has been placed on two different ground plane shapes (circular and square) for analyses of their performances. These antennas were designed in FEKO, an electromagnetic simulation software and their performance is assessed in terms of bandwidth and directivity. The results obtained shows that the antennas exhibit wideband and high directivity with square loop antenna placed on a square ground plane having slight advantages over the other antennas with respect to their bandwidth and directivity. Experimental results added for the same antenna, confirmed its performance in terms of the measured parameters are in good agreement with simulation results.

2017

Wideband Dipole Antennas with Parasitic Elements for Underwater Communications

Autores
Aboderin, O; Pessoa, LM; Salgado, HM;

Publicação
OCEANS 2017 - ABERDEEN

Abstract
Propagation of underwater electromagnetic signals for real-time transmission and reception of data gathered during a survey mission between an Autonomous Underwater Vehicle (AUV) and underwater sensor nodes or a docking station, continues to generate a lot of interest worldwide. To this end, underwater antennas will play a significant role in ensuring good data rates and propagation distances for various underwater applications. In this paper, the performance of two dipole antennas with different parasitic elements is assessed through simulation for usage in fresh water and operating in the High Frequency (HF) band. The antennas were designed in FEKO, an electromagnetic simulation software and their performance is assessed in terms of bandwidth, directivity and antenna-to-antenna distance. The results obtained show that these antennas exhibit wide bandwidth, which is important to achieve high data rates. Experimental results of the reflection coefficient of the fabricated antenna measured in fresh water are given that agree well with the simulation results.

2017

Performance evaluation of antennas for underwater applications

Autores
Aboderin, O; Pessoa, LM; Salgado, HM;

Publicação
2017 Wireless Days, WD 2017

Abstract
The capability of an Autonomous Underwater Vehicle (AUV) or Remote Operated Vehicles (ROVs) to communicate with underwater sensor nodes or a docking station, for the exchange or transfer of data gathered during a survey mission, requires an high-speed short-range communication link. This is important because of the global attention to the underwater communication applications. To this end, underwater antennas will play a significant role in ensuring good data rates and propagation distances for these applications. In this paper, the performance of three antennas, specifically, loop, dipole and J-pole is assessed through simulation for usage in fresh and sea water operating in the High Frequency (HF) band. The antennas were designed in FEKO, an electromagnetic simulation software and their performance is assessed in terms of bandwidth and directivity. The results obtained shows that the J-pole antenna has significant advantages in term of the measured parameters over the other antennas. Experimental results of the reflection coefficient of the J-pole antenna in fresh water are given that agree well with the simulation results. © 2017 IEEE.

2017

Europe and the Future for WPT COST Action IC1301 Team

Autores
Carvalho, NB; Georgiadis, A; Costanzo, A; Stevens, N; Kracek, J; Pessoa, L; Roselli, L; Dualibe, F; Schreurs, D; Mutlu, S; Rogier, H; Visser, H; Takacs, A; Rocca, P; Dimitriou, A; Michalski, J; Raida, Z; Tedjini, S; Joseph, W; Duroc, Y; Sahalos, JN; Bletsas, A; Samaras, T; Nikoletseas, S; Raptis, TP; Boaventura, A; Collado, A; Trevisan, R; Minnaert, B; Svanda, M; Pereira, M; Mongiardo, M; Popov, G; Pan, N; Aubert, H; Viani, F; Siachalou, S; Kant, P; Vera, GA; Polycarpou, AC; Cruz, P; Mastri, F; Mazanek, M; Santos, H; Alimenti, F; Garcia Vazquez, H; Pollin, S; Poli, L; Belo, D; Masotti, D; Machac, J; Tavares, V; Mezzanotte, P; Ndungidi, P; Oliveri, G; Fernandes, R; Salgado, H; Moeyaert, V; Massa, A; Goncalves, R; Pinho, P; Monti, G; Tarricone, L; Dionigi, M; Russer, P; Russer, J;

Publicação
IEEE MICROWAVE MAGAZINE

Abstract
This article presents European-based contributions for wireless power transmission (WPT), related to applications ranging from future Internet of Things (IoT) and fifth-generation (5G) systems to high-power electric vehicle charging. The contributors are all members of a European consortium on WPT, COST Action IC1301. WPT is the driving technology that will enable the next stage in the current consumer electronics revolution, including batteryless sensors, passive RF identification (RFID), passive wireless sensors, the IoT, and machine-to-machine solutions. The article discusses the latest developments in research by some of the members of this group.

2017

Context-Aware Personalization Using Neighborhood-Based Context Similarity

Autores
Otebolaku, AM; Andrade, MT;

Publicação
WIRELESS PERSONAL COMMUNICATIONS

Abstract
With the overwhelming volume of online multimedia content and increasing ubiquity of Internet-enabled mobile devices, pervasive use of the Web for content sharing and consumption has become our everyday routines. Consequently, people seeking online access to content of interest are becoming more and more frustrated. Thus, deciding which content to consume among the deluge of available alternatives becomes increasingly difficult. Context-aware personalization, having the capability to predict user's contextual preferences, has been proposed as an effective solution. However, some existing personalized systems, especially those based on collaborative filtering, rely on rating information explicitly obtained from users in consumption contexts. Therefore, these systems suffer from the so-called cold-start problem that occurs as a result of personalization systems' lack of adequate knowledge of either a new user's preferences or of a new item rating information. This happens because these new items and users have not received or provided adequate rating information respectively. In this paper, we present an analysis and design of a context-aware personalized system capable of minimizing new user cold-start problem in a mobile multimedia consumption scenario. The article emphasizes the importance of similarity between contexts of consumption based on the traditional k-nearest neighbor algorithm using Pearson Correlation model. Experimental validation, with respect to quality of personalized recommendations and user satisfaction in both contextual and non-contextual scenarios, shows that the proposed system can mitigate the effect of user-based cold-start problem.

2017

2D/3D Video Content Adaptation Decision Engine Based on Content Classification and User Assessment

Autores
Fernandes, R; Andrade, MT;

Publicação
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON NUMERICAL ANALYSIS AND APPLIED MATHEMATICS 2016 (ICNAAM-2016)

Abstract
Multimedia adaptation depends on several factors, such as the content itself, the consumption device and its characteristics, the transport and access networks and the user. An adaptation decision engine, in order to provide the best possible Quality of Experience to a user, needs to have information about all variables that may influence its decision. For the aforementioned factors, we implement content classification, define device classes, consider limited bandwidth scenarios and categorize user preferences based on a subjective quality evaluation test. The results of these actions generate vital information to pass to the adaptation decision engine so that its operation may provide the indication of the most suitable adaptation to perform that delivers the best possible outcome for the user under the existing constraints.

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