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  1. 11

    i-ETC - Launching a New Open Access Academic Journal

    Publication
    by Fantoni, Alessandro
    Other Authors: Marques, Paulo; Costa, João; Ferreira, Artur; Filipe, Porfírio; Jesus, Rui et al.
    This paper introduces the general editorial policy of i-ETC, a new online Open Access Journal. The publication of this academic journal is based on the software Open Journal System and it is maintained by the Department of Electronics, Telecommunications and Computer Engineering (DEETC), at the High Institute of Engineering of Lisbon (ISEL) in Lisbon.
  2. 12

    Backscatter radio communication for IoT applications

    Publication
    by Correia, Ricardo
    Other Authors: Pinho, Pedro; Carvalho, Nuno
    The so called Internet of Things (IoT) is progressivelybecoming a normal thing in everyone daily lives. Thedesire of connecting everyday objects to the internet and to eachother, to interact with other users and machines, is increasinglybecoming a reality. In this context, where billions of connectedobjects are expected to be ubiquitously deployed worldwide, thefrequent battery maintenance of wireless nodes is undesirableor even impossible. The growth of the devices will be madepossible only if the sensors battery needs are eliminated orreduced significantly. For low power sensors and devices, carefulpower management and power conservation are critical to devicelifetime and effectiveness. One of the possible solutions is tochange completely the paradigm of the radio transceivers in thewireless nodes of the IoT system. The new paradigm should beable to communicate and to enhance the power to the sensor byusing only electromagnetic waveforms transmitted over the air,in order to make the Wireless Power Transfer (WPT) concept areality.
  3. 13

    Optics in Data Processing and Data Transmission

    Publication
    by Frazão, João Manuel
    Today optical systems are more and more important in data communications (optical fibers) and are also becoming important in data processing (optical and quantum computing) allowing for a fully optical communication  network where all signals will be processed and transmitted in the optical domain. This paper gives an overview of optical fiber communications and analyses some optical devices and applications such as optical computing, holographic memory and optical pattern recognition.
  4. 14

    Inverted-L Antenna (ILA) Design Using Fractal for WLAN USB Dongle

    Publication
    by Luo, Qi
    Other Authors: Pereira, J.R.; Salgado, H.M.
    This work presents an Inverted-L antenna design using the fractal geometry for dual band WLAN (2.4/5.2GHz) USB dongle application. The proposed antenna has the advantages of compact size, wide operation bandwidth and easy fabrication. The experimental results show that it has a S11<-10 dB bandwidth from 2.25 to 2.60 GHz and 5.06 to 5.62 GHz. The radiation performances of the proposed antenna in free space and when connected to a laptop computer were also studied in this work. The proposed antenna was designed and optimized by using Ansoft HFSS V13.
  5. 15

    APC speech coding techniques applied to ECG signals

    Publication
    by Meneses, Carlos
    Other Authors: Lourenço, André; Martins, Guilherme; Silva, Daniel
    This paper describes an ECG signal coding with an adaptive predictive coding scheme using speech techniques like linear predictive coding and long-term prediction.
  6. 16

    LEMPEL-ZIV SLIDING WINDOW UPDATE WITH SUFFIX ARRAYS

    Publication
    by Ferreira, Artur
    Other Authors: Oliveira, Arlindo; Figueiredo, Mario
    The sliding window dictionary-based algorithms of the Lempel-Ziv (LZ) 77 family are widely used for universal lossless data compression. The encoding component of these algorithms performs repeated substring search. Data structures, such as hash tables, binary search trees, and suffix trees have been used to speedup these searches, at the expense of memory usage. Previous work has shown how suffix arrays (SA) can be used for dictionary representation and LZ77 decomposition. In this paper, we improve over that work by proposing a new efficient algorithm to update the sliding window each time a token is produced at the output. The proposed algorithm toggles between two SA on consecutive tokens. The resulting SA-based encoder requires less memory than the conventional tree-based encoders. In comparing our SA-based technique against tree-based encoders, on a large set of benchmark files, we find that, in some compression settings, our encoder is also faster than tree-based encoders.
  7. 17

    Wireless Communication Based on Chirp Signals for LoRa IoT Devices

    Publication
    by Fialho, Vitor
    Other Authors: Azevedo, Fernado
    This paper presents the study of chirp signals for wireless communications between Internet of Thing devices used on low power wide area networks. Up and down chirp concept is introduced as well as the chirp spread spectrum concept. A computationally efficient symbol decoding method is presented based of discrete Fourier transform as an alternative to typical coherent detection. The proposed simulation LoRa model is implemented in MATLAB allowing the communication system evaluation based on bit error rate and packet error rate.
  8. 18

    An implementation on GNURadio of a new model to ISDB-Tb using FBMC

    Publication
    by Hengles Almeida, Jefferson Jesus
    Other Authors: Akamine, Cristiano; Lopes, Paulo
    The modulation technique Filter Bank Multi Carrier (FBMC) is an alternative widely studied in order to replace Orthogonal Frequency Division Multiplexing (OFDM) in wireless telecommunications systems. The fact that FBMC does not use Cyclic Prefix and uses Polyphase Filters allows improvements in bit rate, bandwidth efficiency and robustness against multipath channel impairments. This implementation can bring advantages to Digital TV case in comparison to the traditional OFDM based systems because of the need to transmit higher resolution videos such as 4K and 8K. This article presents a study on the use of FBMC in Integrated System Digital Broadcasting Transmission B (ISDB-Tb), developing an application on GNURadio environment, analysing Bit Error Rate (BER) and power spectrum curves in a multipath channel.
  9. 19

    EYE GAZE TRACKING SYSTEM FOR ADAPTED HUMAN-COMPUTER INTERFACE

    Publication
    by Santos, Rafael Lopes
    Other Authors: Abrantes, Arnaldo; Jorge, Pedro Mendes
    This work describes the implementation of an eye gaze tracking system for a natural user interface, based only on non-intrusive devices, like Intel RealSense camera. Through image processing, the implemented system is able to convert face elements to the corresponding focus point on the computer screen. Tests show promising results.
  10. 20

    Room Temperature Photoluminescence and Photoconductivity of Wet Chemical Deposited ZnO Nanowires Used for Solar Cells

    Publication
    by Bhattacharyya, Soumya Ranjan
    Other Authors: Ayouchi, Rachid; Pereira, Joao; Schwarz, Reinhard Horst
    ZnO 1-D nanostructures (nanowires) were deposited by a two-step wet chemical process. The dimensions of wires were about 100 nm - 1100 nm in length and about 20 - 120 nm in diameter. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique was used to obtain the microstructural information from the films. The nanowire films were also characterized optically by transmittance measurement and room temperature photoluminescence (PL) measurements. The transport properties of the samples were characterized by performing transient photoconductivity (TPC) experiments.