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Mariam Tlili, Manel Ben Romdhane, Asma Maalej, François Rivet, Dominique Dallet, Chiheb Rebai
Compression Study of Continuous-Time Sampled ECG Data for e-Health Applications

The study presented in this paper describes the compressibility of continuous-time sampled electrocardiogram (ECG) signals. The compression method is based on the orthogonal matching pursuit (OMP) algorithm applied to discrete Haar, Daubechie and Biorthogonal wavelets. Comparative results show that Biorthogonal and Daubechie wavelet families offer up to 49 % and 43 % reductions of the overall number of amplitude samples, respectively. However, Haar wavelets, the less complex wavelet family, discard only 12 % of the data and lead to higher computation time than Daubechie family.

Daniel Mihai Toma, Joaquín del Río, Enoc Martinez, Alessandra Casale, Alberto Figoli, Diego Pinzani, Pablo Cervantes, Pablo Ruitz, Eric Delory, Simone Memè
An Embedded Passive Acoustic Device for RealTime Hydroacoustic Surveys

In this paper, we provide a comprehensive description of cost-efficient, innovative and interoperable ocean passive acoustics sensors systems, developed within the European FP7 project NeXOS (Next generation Low-Cost Multifunctional Web Enabled Ocean Sensor Systems Empowering Marine, Maritime and Fisheries Management), which can be deployed both on fixed and mobile platforms. Within this context, we designed and developed two passive acoustic sensors, A1 and A2, as new embedded passive acoustic device, low power and innovative digital hydrophone systems. An important part of the effort is focus on the need for greater dynamic range and the integration on autonomous platforms, such as gliders and profilers. A1 is a standalone small, compact, low power, low consumption digital hydrophone with embedded pre-processing of acoustic data, suitable for mobile platforms with limited autonomy and communication capability. A2 consists of four A1 digital hydrophones with Ethernet interface and one master unit for data processing, enabling real-time measurement of underwater noise and of several soundscape sources.

Cosmin Ursache, Catalin Damian, Sinica Alboaie, Lenuta Alboaie, El Mehdi Stouti
Bringing executable choreographies to the IoT

The Internet of Things (IoT) is growing fast as popularity, demand, availability and in the same time too slow on some regards [1]. Many companies that have interest in IoT are trying hard to secure a good part of the market by forming different associations or by designing “closed” standards under the blanket of interoperability and collaboration. No matter what level of the IoT we analyse, there are already directions that guide how things should be made or how they should work. Fortunately for smaller companies driven by communities there are still good opportunities to collaborate between them and target a more important challenge: build sustained technology that can adapt and evolve in the rhythm that is need it.

Daniele Bibbo, Ivan Bernabucci, Andrea Scorza, Francesco Orsini, Salvatore Andrea Sciuto, Maurizio Schmid
Using IMUs to monitor body kinematicswhile cyclingin different in-field conditions

Wearable sensors and system scan profitably be used in bicycle riding to help evaluating the performance and provide trainers and athletes with indications about the strategy used to execute the gesture. In this paper a set of commercial Inertial Measurement Units (IMUs) was used to assess body segment accelerations while pedalling outdoor in different conditions, obtained combining tracks with different slopes and different positions on the saddle. Results show an evident variation on data recorded by the IMUs placed in the upper body segments, as a function of both slope and saddle position, that can be interpreted as a different inertial contribution of the trunk to the gesture. This information can be used to both evaluate different strategies and monitor the evolution of a functional recovery while using cycling in rehabilitation contexts.

George-Andrei Ursan, Romeo Cristian Ciobanu, Costel Donose, Maria Ursan
Modeling and Simulation of Electromagnetic Absorption Properties of the Different Nanostructured Composites

The relatively recent development of the capability of computing systems and of electromagnetic numerical methods, that benefit from these capabilities, allows the use of the electromagnetic simulation as a accurately method to investigate low-loss materials. Successful determination of parameters by simulation and subsequent application of the NRW procedure (The working procedure originally proposed by Nicolson, Ross and Weir) has brought to the attention of researchers this procedure.

Yingyue Hu, Pedro M. Ramos, Fernando M. Janeiro
Artificial Bee Colony Algorithm for Peak-to-Peak Factor Minimization in Periodic Signals

Minimization of the peak-to-peak factor in multiharmonic signals is highly desirable in many signal processing applications such as impedance spectroscopy and acoustic signal generation. This minimization allows optimized signal to noise ratio within a given signal amplitude range. Careful selection of the phases of each harmonic of a multiharmonic signal may lead to much better peakto-peak factors when compared to zero or random phases. This paper presents the use of an Artificial Bee Colony algorithm in the minimization of the peak-topeak factor by phase optimization of multiharmonic signals. The obtained results are compared with the Schroeder formula and the clipping algorithm. The computation time of each algorithm is also presented for comparison.

A. Carullo, A. Castellana, A. Vallan, A. Ciocia, F. Spertino
Degradation rate of eight photovoltaic plants: results during six years of continuous monitoring

The results of six years of continuous monitoring are presented in this paper that refer to eight outdoors PhotoVoltaic (PV) plants. The monitored plants are based on different technologies: mono-crystalline silicon (m-Si), poli-crystalline silicon (p-Si), string ribbon silicon, Copper Indium Gallium Selenide (CIGS) thin film and Cadmium Telluride (CdTe) thin film. Mono-crystalline silicon modules and thin-film modules are used both in fixed installation and on x-y tracking systems. The results are expressed in terms of degradation rate of the efficiency of each PV plant, which is estimated from the measurements provided by a multi-channel dataacquisition system that senses both electrical and environmental quantities. A comparison with the electrical characterization of each plant obtained by means of the transient charge of a capacitive load is also proposed. The capacitive-load technique has been implemented immediately after the installation of the PV plants and after 78 months of operation. The obtained results show that both the m-Si plants in fixed installation and on the tracking system had a negligible degradation, while p-Si and string-ribbon Si exhibited a moderate degradation. Higher was the degradation obtained for the thin-film based plants, with a worst behaviour of the plants installed on the tracking systems.

Vladimir Vujicic, Aleksandar Radonjic, Dragana Naumovic-Vukovic, Nemanja Gazivoda, Platon Sovilj
Digital Measurement of Line Current with the Use of Virtual Short Circuit Method

The paper describes a method of very accurate measurement of line current using a current transformer (CT) in a virtual short circuit. The key systematic error, amplified error due to offset of operational amplifier that leads CT in a virtual short circuit, is easily calculated using a stochastic digital measurement method and eliminated from measured RMS value of line current. Since the 2-bit stochastic digital measurement method is defined using a very simple hardware which has a small number of sources of systematic error, sources are easily identified and it is described how to eliminate these errors. A complete measurement scheme of line current is presented and applied in quadruple three-phase power analyser with MM4 type designation. MM4 is a key component of the redundant measuring system in the Electric Power Grid of Serbia.

Cornel Balint, Aldo De Sabata
Measurements of Short-Time Spectrum Occupancy for Ionospheric Propagation

Results concerning short time spectrum occupancy in the 3-15 MHz spectrum range of the High Frequency band (3-30MHz) for a 24-hour period are reported. Measurements have been completed using an USRP equipment and a broadband HF antenna in February – March 2017. Results indicate that convenient free bandwidths exist for short time intervals. These free frequency intervals can be used for opportunistic transmissions in an emergency communications system. Spectrum occupancy measurements can also be considered by authorities when deciding on spectrum allocation.

Daniel M. Toma; QuimJané, Montserrat Carbonell-Ventura, Immaculada Massana, Joaquin del Rio
Experimental validation and modelling of electromagnetic kinetic harvester for oceans drifters

Harvesting the mechanical energy of ocean motion are finding different applications for offshore exploration and ocean monitoring. Because of the very low and varying frequency, from 0.1Hz to 2Hz, harvesting this energy has an important hurdle. In this paper, we provide a comprehensive study of a new idea to supply low power oceanic drifters using an electromagnetic vibration harvester. Therefore, this work presents a solution on how to generate power from low frequency driven electromagnetic energy harvester for an ocean drifter self-powered system. A prototype with a proposed electronic harvesting system is built and tested in a real medium, showing the results before concluding the article.

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