Programa del congreso

This work describes a new design strategy for improving the power handling capability (PHC) of groove gap waveguides (GGW). First, a theoretical analysis is carried out to study the distribution of the quasi-TE10 mode and the variation of the PHC for different configurations and frequencies. Then, in order to minimize the strength of the maximum electric field above the pins, three of the main geometrical dimensions of the nails are optimized. Finally, the numerical results show that by using this strategy, the corona discharge power thresholds can be enhanced without degrading the electrical response.

In this work a microstrip line to empty substrate integrated waveguide (ESIW) transition based on Bézier curves has been designed for different substrate heights and for different working band frequencies (WR-75 and WR-42). The transition is fully integrated into the ESIW guide and does not require an additional taper in the microstrip line. Therefore, radiation loss is reduced. The microstrip to ESIW transition is realized by applying Bézier curves to a dielectric slab embedded into the ESIW and at its corners (ESIW). Bézier curves allow to shape the transition with a greater control as compared to exponential or gradient curves used in previous works. Besides, a prototype has been manufactured obtaining good agreement between the simulated and the measured results.

A new compact balanced-to-balanced dual-band diplexer composed of two balanced dual-band bandpass filters in a multilayer configuration is proposed in this contribution. The two balanced bandpass filters are based on the use of magnetically coupled open-loop resonators. The magnetic coupling results in a strong inherent common-mode rejection, greater than 40 dB within all of the passbands. The four passbands are close to each other in under 700 MHz in the L band, used for many applications such as mobile services or satellite navigation. Measurements of a prototype example are provided to validate the obtained simulation results and verify the value of the proposed structure.

Additive tridimensional printers have opened new applications of dielectric and conductive materials for microwaves systems. Manufacturing dielectric pieces by 3D printers is relatively easy. The knowledge of dielectric properties, relative dielectric constant and loss tangent, allows the design of microwave components such as lenses or molding surfaces for microwave and millimeter wave absorbers. The experimental measurements of dielectric properties of Polylactic Acid (PLA) and resin materials commonly used in 3D printers, in frequency bands from 8 to 110 GHz, by using different methods, have permitted the design of special shaped molding surfaces for the manufacturing of microwave and millimeter wave absorbing devices. This paper presents characterization methods and experimental results.

We present a detailed design of a radio-frequency graphene-based phase shifter. The operating principle of the system consists in loading a transmission line (TL) with a bias-tunable capacitor implemented as a state-of-the-art metalinsulator- graphene (MIG) diode. In the analysis carried out in this work, the focus is set on obtaining a full comprehension of the main figures of merit of a unit-cell stage, which is formed by a TL loaded with the MIG diode, so that it can be arbitrarily replicated and thus periodically concatenated, guarantying low insertion losses (IL) and high return losses (RL). Such a distributed system allows achieving a desired phase shift range for a targeted application. In this regard, we predict the operation of a 10-stage phase shifter at 3 GHz providing an almost linear phase shift range of around 24.09 degrees in the bias window [-1.5, 0.5]V, with insertion losses (IL) of 1.29 dB and return losses (RL) of 20.14 dB.

Los sistemas de detección han recibido recientemente una atención considerable debido a la importancia del seguimiento de las personas infectadas durante la pandemia de SARS-CoV-2. Estas implementaciones pueden ser muy útiles para encontrar posibles víctimas en el contexto de la respuesta de emergencia, especialmente en situaciones en las que el GPS no está disponible o la inspección por imagen no es posible. Entra en juego la radiofrecuencia, y concretamente, dispositivos que transmiten periódicamente con bajo consumo de energía. Con el auge del Internet de las Cosas y la plétora de dispositivos portátiles utilizados en la vida cotidiana, como un smartphone, Bluetooth Low Energy (BLE) puede ayudar considerablemente en la localización de personas perdidas.

Este trabajo presenta un sistema de detección de víctimas en un entorno no estructurado, mediante una implementación real de una plataforma robótica de detección cercana basada en BLE para intervenciones SAR. Con el fin de estimar la distancia entre un agente robótico y las posibles víctimas dentro de un área experimental, se utiliza un modelo de pérdidas de trayectoria que ha sido calibrado para detectar balizas dentro de un rango de 25 metros en entornos accidentados. El esquema propuesto se ha probado en escenarios realistas durante ejercicios SAR.

An emerging number of new wireless technologies are paving the way for industrial IoT (IIoT) by enabling the monitoring and automation of different stages of the manufacturing process. Such industrial environments are characterized by high electrical noise, long distances, and difficult access to deploy a sensor network. In order to overcome these problems, most of the main technologies make use of license-free bands below Gigahertz and considerable transmission power, which is a problem in some scenarios where it is necessary to achieve a minimum bandwidth with a low power consumption.

This article proposes the study and evaluation of a wireless system for real-time oxygen monitoring in industrial confined areas. This type of working areas is susceptible to sudden variations in oxygen levels, so, to ensure the safety of the operators, it is necessary to perform a real-time monitoring of oxygen values. Bluetooth 5 will be used for this task, as it operates in the 2.4GHz ISM band and provides a better range and more bandwidth than previous versions of the standard.

Therefore, the objective of this article is to describe and show some initial results of a monitoring system that finds a balance between transmission speed, consumption, channel occupancy and range in industrial confined spaces. To achieve such a goal and due to the considerable difference in range that exists between Bluetooth 5 and the most popular LPWAN (Low-Power Wide Area Network) technologies, a mesh topology was chosen instead of the traditional centralized star topology provided by most LPWANs. Thus, the information can be collected from multiple monitoring sensors and then forwarded through mesh nodes that act as repeaters, which allow for achieving larger communications distances.

The properties of a web page have a strong impact on the experience of web users. In this work, a classification method based on unsupervised clustering to group web pages into classes based on download content may affect the Quality of Experience (QoE) perceived by the user and their characterization through the set of web technologies they use is proposed. Groups are defined based on standard Multipurpose Internet Mail Extensions (MIME) content breakdown and external subdomain connections, obtained through in-browser, application-level measurements to 500 popular websites. The collected data is divided into groups with a classical unsupervised learning algorithm, namely K-means clustering. Finally, groups are characterized according to the set of web technologies used. Results show how web pages are classified into six groups and their cluster characteristics and how JQuery (most popular JavaScript) impacts web page loading time.

Virtual Reality (VR) arises as one of the current cutting-edge technologies. Its applications address educational and entertainment uses. This work presents a framework to assess video 360 service performance over VR headsets through Key Quality Indicators (KQIs). This service differs from traditional video streaming approaches due to its immersive experience, which allows the user to enjoy omnidirectional multimedia. However, the service experience must be guaranteed in order to avoid side effects such as cybersickness or disorientation. The testbed is conformed for a Unity video player for DASH and HLS, which playbacks multimedia sources from a video server located in the cloud while KQI measuring tasks are performed. Finally, a performance comparison between technologies is provided. Results from the KQI measurement highlight the potential of the new generation of mobile networks in the provision of service with high-quality levels of experience.

Nowadays, Unmanned Aerial Vehicles (UAVs) have experienced an increased growing as key enablers of new applications, including first aid, surveillance and monitoring, agriculture, disaster management or even as leisure activities. This paper briefs on the LTE controlled drone. First, the construction and connection platform of the drone have been detailed. Afterward, a study of the drone network performances, such as packet length, time between packets and bit-rate is made. As it is known, for First Person View (FPV) applications, a low latency communication is needed to achieve a suitable Quality of Experience (QoE). Hence, graphical results of the network latency is presented over different communications links. The analysis has been carried out by collecting traces at network level between the drone and the PC from where it is controlled.

Sound Event Localization and Detection (SELD) is a problem related to the field of machine listening whose objective is to recognize individual sound events, detect their temporal activity, and estimate their spatial location. Thanks to the emergence of more hard-labeled audio datasets, deep learning techniques have become state-of-the-art solutions. The most common ones are those that implement a convolutional recurrent network (CRNN) having previously transformed the audio signal into multichannel 2D representation. The squeeze-excitation technique can be considered as a convolution enhancement that aims to learn spatial and channel feature maps independently rather than together as standard convolutions do. This is usually achieved by combining some global clustering operators, linear operators and a final calibration between the block input and its learned relationships. This work aims to improve the accuracy results of the baseline CRNN presented in DCASE 2020 Task 3 by adding residual squeeze-excitation (SE) blocks in the convolutional part of the CRNN. The followed procedure involves a grid search of the ratio parameter (used in the linear relationships) of the residual SE block, whereas the hyperparameters of the network remain the same as in the baseline. Experiments show that by simply introducing the residual SE blocks, the results obtained are able to improve the baseline considerably.

We present our solution for the IEEE Signal Processing Cup 2021 challenge. The goal is to maximize the weighted average achievable rate for a set of N_u = 50 users assisted by an intelligent reflecting surface (IRS). We combined a modified least-squares smoothing estimator, several variations over the strongest-tap maximization (STM) algorithm, and a final fine-tuning optimization that explored solutions in the vicinity of the STM solutions. Simulations show that our IRS configurations yield an estimated weighted achievable rate slightly over 117 Mbps.

In the context of statistics, survival analysis is commonly used for clinical research, although the biased and/or incomplete nature of the clinical data hampers its direct application. This work presents a survival analysis using standard methods (Kaplan-Meier estimator and Cox model), applied to kidney transplantations in the population of Andalusia, with data collected between 2006 and 2019 and following a methodology for the adequacy of the clinical data. The study allows the analysis of the influence of the donor age in the outcomes of renal transplant. As result, we conclude that the donor age is an important factor for the failure probability of the kidney graft, although differences of this influence can be reported when diverse populations are considered by age ranges.

Virtual reality (VR) experiences are transforming the way cultural heritage institutions exhibit their works of art and the contextual information in which they were conceived. This paper presents a VR experience intended to bring closer to the public the figure of the Dutch painter Piet Mondrian. The tool, completely immersive, make use of Oculus Rift S head mounted display (HMD) to introduce the user in the life and work of this artist. Playing around with “Composition A”, the subject could achieve a better comprehension of the wok itself. The tool, programmed with Unity, guides the subject who is constantly appealed by the numerous interactive elements present in the scene. This application could be extended to any artist or any artwork to shorten the gap between the public and art itself. Digital exhibitions, art museums, universities, are only some of the possible benefited of such immersive tools

In recent years, the main problem to be solved by the whole world has been the Covid-19 pandemic. Most countries have taken measures aimed at reducing mobility as the main tool in the fight against the spread of the virus. This article presents a case study of the impact of mobility in contagions for the municipality of Málaga, Spain. Aggregated point of sale purchase registers are used as mobility data within the area of study. The obtained results hint that commercial activity is not the main vector of contagion on the available data on Málaga, although the data volume is insufficient to draw a sharp conclusion.

In this paper, a range of complex permittivity

estimated from a flat terrain composed of Pinus Pinaster fuel bed

on fire is studied. It was used the Fire Dynamics Simulator (FDS)

to implement the fire environment and the Cold Plasma Model

(CPM) was applied to evaluate the complex permittivity of the

medium. Effects of maximum and minimum permittivities for the

considered time step were explored using the Finite-Difference

Time-Domain (FDTD) method, in order to understand the

impact of a weakly ionised plasma generated during vegetation

combustion, on radiowave propagation.