Showing papers by "Nuno Souto published in 2019"

Smart System for Monitoring and Control of Swimming Pools

Abstract: This paper proposes a new scheme for monitoring and controlling the swimming pool’s quality through a low-cost system based on wireless sensor networks, which can reduce the requirements for human intervention in the swimming pool maintenance. The main purpose of this system is to provide resources savings for the final user in financial and natural resources, contributing to a sustainable environment. This article also presents a mobile application for interacting with the proposed system which enables users with administrator permissions to control some actions in the swimming pool, in order to stabilize some required parameters for its good quality.

WSN Application for Sustainable Water Management in Irrigation Systems

Abstract: This paper introduces a new way of maintaining a sustainable irrigation system, applied to gardens or agricultural fields, replacing human intervention with Wireless Sensor Net-works, in order to achieve a better efficiency in the process that can lead to savings for the final user, not only monetary but also in natural resources, such as water and energy, leading to a more sustainable environment. The system can retrieve real time data and use them to determinate the correct amount of water to be used in the garden in order to keep it healthy. Besides the system architecture, this paper includes a real case scenario implementation and result discussions.

An Alternating Direction Algorithm for Hybrid Precoding and Combining in Millimeter Wave MIMO Systems

Abstract: Millimeter-wave (mmWave) technology is one of the most promising candidates for future wireless communication systems as it can offer large underutilized bandwidths and eases the implementation of large antenna arrays which are required to help overcome the severe signal attenuation that occurs at these frequencies. To reduce the high cost and power consumption of a fully digital mmWave precoder and combiner, hybrid analog/digital designs based on analog phase shifters are often adopted. In this work we derive an iterative algorithm for the hybrid precoding and combining design for spatial multiplexing in mmWave massive multiple-input multiple-output (MIMO) systems. To cope with the difficulty of handling the hardware constraint imposed by the analog phase shifters we use the alternating direction method of the multipliers (ADMM) to split the hybrid design problem into a sequence of smaller subproblems. This results in an iterative algorithm where the design of the analog precoder/combiner consists of a closed form solution followed by a simple projection over the set of matrices with equal magnitude elements. It is initially developed for the fully-connected structure and then extended to the partially-connected architecture which allows simpler hardware implementation. Furthermore, to cope with the more likely wideband scenarios where the channel is frequency selective, we also extend the algorithm to an orthogonal frequency division multiplexing (OFDM) based mmWave system. Simulation results in different scenarios show that the proposed design algorithms are capable of achieving performances close to the optimal fully digital solution and can work with a broad range of configuration of antennas, RF chains and data streams.

Low-cost SDR based FMCW radar for UAV localization

Abstract: In this paper, we study a Software Defined Radio (SDR) based frequency-modulated continuous-wave (FMCW) radar which can be used as a low cost solution for the localization of unauthorized unmanned aerial vehicles (UAV’s). The FMCW radar is evaluated through several simulations implemented in GNU Radio in order to verify its behaviour in the detection of stationary and moving targets as well as the effects of attenuation due to signal propagation and signal noise corruption. The software implemented on GNU Radio will be used as a basis for a future implementation using SDR platforms, namely URSP N210, BladeRF and LimeSDR, combined with high gain antennas and a high power amplifier in order to test the performance of the FMCW radar in real-life scenarios involving the detection of UAV targets.

Anti-UAV Mobile System with RTLS Integration and User Authentication

Abstract: The increased use of Unmanned Aerial Vehicles (UAVs), most known as drones, by civilians has grown exponentially, which has resulted in a greater number of accidents and dangerous situations with drones flying over restricted areas such as airports, public events, and military zones. Creating a mobile system capable of locating the drone position (using a set of sensors) that will be used together with Software Defined Radio (SDR) platforms, efficient jamming and spoofing signals to the communications of the drone. This can be the best solution to mitigate the dangerous problem of UAV near the location before mentioned. The system described in this paper also has a real-time location system and user detection through a biometric sensor to ensure greater security and control over who, when and where the system was used.

Distributed Sensing Solution for Home Efficiency Tracking

Abstract: With the rapid increase of smart devices, keeping track of household consumptions is a service that starts to be automated. This paper presents a proposal for a system based on wireless sensor networks designed for the purpose of monitoring and controlling environment parameters of a smart home. In order to obtain an efficient and inexpensive system, a study was made to select the best hardware and software solutions for this system. This system allows the user, through an Android application, to view all the information collected by the sensors, and consequently act in a way to make his home more sustainable. The main advantage of this system is to take into account that all its components are small, practical and with high efficiency, in addition it allows an easy installation and in order to get involved with the inner environment, another advantage is to allow system interaction with the user.

Extending 5G Capacity Planning Through Advanced Subscriber Behavior-Centric Clustering

Abstract: This work focuses on providing enhanced capacity planning and resource management for 5G networks through bridging data science concepts with usual network planning processes. For this purpose, we propose using a subscriber-centric clustering approach, based on subscribers’ behavior, leading to the concept of intelligent 5G networks, ultimately resulting in relevant advantages and improvements to the cellular planning process. Such advanced data-science-related techniques provide powerful insights into subscribers’ characteristics that can be extremely useful for mobile network operators. We demonstrate the advantages of using such techniques, focusing on the particular case of subscribers’ behavior, which has not yet been the subject of relevant studies. In this sense, we extend previously developed work, contributing further by showing that by applying advanced clustering, two new behavioral clusters appear, whose traffic generation and capacity demand profiles are very relevant for network planning and resource management and, therefore, should be taken into account by mobile network operators. As far as we are aware, for network, capacity, and resource management planning processes, it is the first time that such groups have been considered. We also contribute by demonstrating that there are extensive advantages for both operators and subscribers by performing advanced subscriber clustering and analytics.

Valuation of compounded deferred tax assets for the banking sector, using the binomial CRR algorithm

Abstract: Deferred tax asset (DTA) is a tax/accounting concept that refers to an asset that may be used to reduce future tax liabilities of the holder. In the banking sector, it usually refers to sit...

Frequency Domain Equalization for Single and Multiuser Generalized Spatial Modulation Systems in Time Dispersive Channels

Abstract: In this letter, a low-complexity iterative detector with frequency domain equalization is proposed for generalized spatial modulation (GSM) aided single carrier (SC) transmissions operating in frequency selective channels. The detector comprises three main separate tasks namely, multiple-input multiple-output (MIMO) equalization, active antenna detection and symbol wise demodulation. This approach makes the detector suitable for a broad range of MIMO configurations, which includes single-user and multiuser scenarios, as well as arbitrary signal constellations. Simulation results show that the receiver can cope with the intersymbol interference induced by severe time dispersive channels and operate in difficult underdetermined scenarios where the total number of transmitter antennas is substantially larger than the number of receiver antennas.

Application of a Mesh Free Monte-Carlo Method to the Analysis of Dielectric Slabs in Electromagnetics

Abstract: In this paper, we present a probabilistic MonteCarlo method to simulate the electromagnetic field in multiple interface problems based on transmission lines We present numerical results for the simplest case of the propagation of gaussian pulses and sinusoidal sources in lossy and lossless dielectric slabs which demonstrate the applicability of the method to solve network problem in microwave theory We also present a methodology to obtain the amplitude and phase associated with every point in the domain without resorting to fourier transformations This method is an important achievement in the development of our Monte-Carlo method because otherwise we would have to integrate the field over time to achieve similar results, which would be unpractical for a Monte-Carlo method Finally, we compare our results with well established theory to validate the methods

Iterative Signal Detection with Frequency Domain Equalization for Generalized Spatial Modulation Aided Single-Carrier Systems

Abstract: In this paper, a low-complexity iterative detector with frequency domain equalization is proposed for generalized spatial modulation (GSM) aided single carrier (SC) transmissions in frequency selective channels. The detector comprises three main separate tasks namely, multiple-input multiple-output (MIMO) equalization, active antenna detection and symbol wise demodulation. This approach makes the detector suitable for a broad range of MIMO configurations, which includes single-user and multiuser scenarios, as well as arbitrary signal constellations. Simulation results show that the receiver can cope with the intersymbol interference induced by severe time dispersive channels and operate in difficult underdetermined scenarios where the total number of transmitter antennas is substantially larger than the number of receiver antennas.

Design of a Novel THz Sensor for Structural Health Monitoring Applications

Abstract: In this paper, we propose a study on the characterization, design and simulation of a THz sensor for applications in Structural Health Monitoring (SHM). The proposed sensor is assembled using two frequency selective surfaces (FSSs) based on metamaterial wire resonators. We present a theoretical model to describe its electromagnetics which is used not only to understand the physical principles underlying the functioning of the sensor but also to determine a set of optimized parameters for its operation in the THz window from 395 GHz to 455 GHz. We present our numerical simulations, involving both electromagnetic and mechanical simulation techniques, to determine the reflectance profile of the sensor as a function of applied force. In this study we considered the possibility of using two thermoplastic polymers as host materials: High-Density PolyEthylene (HDPE) and PolyTetraFluoroEthylene (PTFE). The two sensors have a good dynamic range and comparable characteristics. However, we found that with HDPE it is possible to construct a sensor with a more linear response, although not as sensitive as in the case of PTFE. With HDPE we are able to pass from a situation of full transparency to almost full opacity using only its linear operating zone.

Analysis of the Interaction between THz Waves and Low Cost Plasma Detectors for the Development of Stand-Off Imaging Systems

Abstract: Over the past few years, the Terahertz (THz) band has been seen as quite promising in fields of spectroscopy and imaging. Most of the current manufacturing methods for THz emission and detection devices are limited due to the associated cost and complexity, therefore alternative ways have been sought driven by the availability of new technologies. From recent research in the field of imaging, commercially available Glow Discharge Detectors (GDDs) have been found to be an interesting solution because of their low cost and efficiency in detecting electromagnetic (EM) radiation from microwave to higher frequencies of the electromagnetic spectrum. Several studies have been carried out in the scope of millimeter/sub-millimeter waves to understand how its detection mechanism changes for higher frequencies and how the mechanisms of plasma generation influence the device's performance. In this paper, we aim to study the interaction between THz waves and the structure of a GDD, namely, its reflection, transmission and losses. Numerical modelling of electromagnetics, by solving the Maxwell’s equations, has been undertaken for this type of device using different gas pressures of the lamp. Our results show that these devices are not optimized for the THz domain.