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In order to fully exploit the scarce spectrum, antenna arrays are incorporated into wireless communication devices in 4G and 5G communication networks to deploy MIMO-OFDM systems. Recently, the least squares Khatri–Rao factorization has been applied to MIMO-OFDM systems for semi-blind joint channel and symbol estimation. Its cubic computational complexity is prohibitive when the number of transmit...
Frequently, postoperative patient care requires a long period of observation in hospitals by the medical board. During this observation period, the medical board manually inserts time to time vital information of the patients into the medical information system. Such manual procedure can be improved and become more reliable if the patients are equipped with wearable devices that allow the real-time...
In Big Data Processing we typically face very large data sets that are highly structured. To save the computation and storage cost, it is desirable to extract the essence of the data from a reduced number of observations. One example of such a structural constraint is sparsity. If the data possesses a sparse representation in a suitable domain, it can be recovered from a small number of linear projections...
In order to understand brain mechanisms and functionalities, neural probes with electrode arrays are incorporated into mice and Local Field Potentials (LFP) are recorded indicating the activities of groups of neurons. Next, the brain activity can be analyzed in terms of Current Source Density (CSD), which are computed via the LFP. In this paper, we propose the analysis of the somatosensory cortex...
Energy harvesting has become very attractive due to the extended usage time of devices. Among several forms of recycling energy, radiofrequency (RF) harvesting has been suggested due to its wide availability mainly in urban areas. Its applications range from sensor nodes to charging low power consumption portable devices and depend on the amount of antennas. In this paper, we evaluate the feasible...
Detecting the sinusoidal order is a prerequisite step for parametric multidimensional sinusoidal frequency estimation methods, whose applications range from radar and wireless communications to nuclear magnetic resonance spectroscopy. Although the Bayesian information criterion (BIC) has been commonly applied for model order selection, its application to sinusoidal order estimation is recent. By means...
Electricity demand time series are stochastic processes related to climate, social and economic variables. By predicting the evolution of such time series, electrical load forecasting can be performed in order to support the electrical grid planning. In this paper, we propose a Kalman based load forecasting system for daily demand forecasting. Our proposed approach incorporates a Principal Component...
Microphone arrays can be incorporated in several devices ranging from hearing aids and bioacoustic recording equipment to teleconference phones and forensic sound recorders in order to attenuate the interference of unwanted sounds. The separation of speech mixtures can be easily performed on the frequency domain independently for each frequency component. However, in order to combine the separated...
Digital audio recordings are an important source of evidences related to various crimes and conflicts. The authentication of this source of evidence is often a necessary and critical task, but still subject to many challenges. In order to identify audio tampering we present a new technique to detect deletions and insertions of audio snippets by exploiting anomalous variations in Electric Network Frequency...
Forensic Speaker Comparison (FSC) is used in a legal process to compare speech patterns from a known speaker, the suspect and from an unknown offender, producing evidence for the conviction or the elimination of the suspect. The FSC methodology used most, applied worldwide by forensic experts, is based on linguistic-acoustic analysis. Fundamental Frequency (F0) is the acoustic parameter used most...
Technological advances in information and communications systems are enabling access to education for millions of students, regardless of their geographical location. In this sense, distance learning schools take advantage of technological tools, such as course management systems (CMS) and their plugins. This work proposes a plugin for the e-learning platform Moodle that automatically sends e-mail...
One of the main limitations that still keeps Wireless Sensor Networks (WSNs) from being adopted in a large scale is the limited energy supply, i.e. the lifetime of the nodes that constitute the network. The wireless communication between nodes is responsible for most of the energy consumed in WSNs. A promising method to improve the energy efficiency is the usage of a Cooperative Multiple Input Multiple...
Many important signal processing techniques such as Spatial Smoothing, Forward Backward Averaging and Root-MUSIC, rely on antenna arrays with specific and precise structures. Arrays with such ideal structures, such as a centro-hermitian structure, are often hard to build in practice. Array interpolation is used to enable the usage of these techniques with imperfect (not having a centro-hermitian structure)...
The usage of antenna arrays brought innumerable benefits to radio systems in the last decades. Arrays can have multidimensional structures that can be exploited to achieve superior performance and lower complexity. However, the literature has not explored yet all the advantages arising from these features. This paper uses tensors to provide a method to design efficient beamformers for multidimensional...
It is impossible to enforce exact responses for each sensor involved in an antenna array. Important signal processing techniques such as Estimation of Signal Parameters via Rotational Invariance (ESPRIT), Forward Backward Average (FBA) and Spatial Smoothing (SPS) rely on sensor arrays with Vandermonde or centro-hermitian responses. To achieve such responses array interpolation is often necessary....
Automatic speaker recognition has become a well-established technique for forensic applications. Since ambient recordings in such applications are obtained with hidden microphones far away from the sound sources, the performance of the speaker recognition can be severely degraded. In this paper, we propose an array signal processing method to compensate for these disturbances by spatially separating...
Data transmission of secondary users in classical cognitive radio networks is not allowed within the sensed band during the sensing period resulting in underutilization of the available spectrum. Aiming at a higher network throughput than in classical approaches, the spectrum sensing is performed at the receiving node of the secondary network instead of the transmitting node. This allows the transmitter...
Due to the increasing energetic demand, solar and eolian electric energy microgenerations are already common for industrial and residential systems. Moreover, other types of emergent microgenerations such as radiofrequency and artificial light recycling are also found in commercial solutions. In this paper, we consider the electric energy microgeneration based on electric eels. First we conduct a...
Energy recycling has become very atractive due to the extended usage time of devices. Among several forms of recycling energy, radiofrequency (RF) harvesting is becoming popular due to its immense availability mainly in urban environments. The possible utilizations for such amount of energy is mainly applicable for sensors nodes and, depending on the quantity of antennas, charging low power consumption...
Sensor arrays with Vandermonde or centro-hermitian responses cannot always be constructed. However, such array response structure can be achieved by means of a mapping which transforms the real array response to an array response with the desired properties by applying array interpolation algorithms. In this work a low-complexity, multi-sector, signal adaptive array interpolation approach that achieves...
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