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In the last years, the environment in which we develop has had various changes, most of them due to major technological changes, and the constant development of Information and Communication Technologies (ICTs). As a result of the advances in ICTs, today it is common to interact through social networks and make constant use of them. For this reason, this paper presents an analysis of the 10 most influential Twitter accounts in Ecuador; the objective of this analysis is to detect what the topics or topics addressed in these accounts are. The Latent Dirichlet Allocation (LDA) algorithm using bag of words (BoW) model and also the Term Frequency–Inverse Document Frequency (TF-IDF) model were used for the analysis, finally finding, if the topics provided by both models are similar.

This document presents the design, simulation and construction of a fractal antenna from the model of a circular resonant antenna at 5.8 GHz. The modifications introduced to the antenna derive in a flame form. The different iterations were simulated using ANSYS HFSS 13.0, to obtain their main characterization parameters such as resonance frequency, bandwidth, return loss and Voltage Standing Wave Ratio. The main modification generated is to replicate the original shape by reducing its size by 0.7 mm in both the width and length of the antenna. The design establishes a characteristic impedance of 50Ω so that it can be coupled to other devices. From the multiple results obtained, it was concluded that the best characteristics are presented in the fourth iteration, where lower return loss and a bandwidth greater than 500 MHz are obtained. With the result of the fourth iteration, the antenna was constructed using the FR4 substrate, with a thickness of 1.6 mm, and a loss tangent of 0.02. A resonance frequency of 5.89 GHz, return loss -39.2 dB and BW of 701.6 MHz was obtained, allowing it to be considered within the Ultra Wide-Band standard.

Dielectric permittivity is one of the most important parameters in the field of telecommunications, since it indicates an interaction value between the substrate and an electric field. Lately the paper has had a great acceptance for the development of new technologies, therefore, the permittivity of the Kraft paper was measured to be used as a substrate, in telecommunications applications. For the measurement of the dielectric permittivity of Kraft paper, a resonant ring structure was designed. The design of the ring requires a frequency of operation or resonance, moreover, to an impedance coupling between the measuring equipment and the resonator. The structure of the resonant ring was simulated obtaining the coefficient of direct transmission (S21), validating the design for its construction. S21 was acquired by the NI-PXI instrument in a practical way; this parameter allows the calculation of the effective dielectric permittivity and later the relative. Finally, the process revealed a value of 1.40, relative dielectric permittivity for Kraft paper.

This document presents the design, simulation and measurement of a new multi-resonant patch antenna, whose shape is based on the graph obtained from the traces of a partial exponential sum in the complex plane. The shapes obtained from these equations are similar to the fractal geometry shapes, that applying to the design of antennas, drift in both Ultra Bandwidth (UWB) and multi-resonance features. In this work we try to verify that the images derived from the exponential sums can have a real application. Using a specific form, the simulation process is detailed to obtain the ideal structure of an antenna that works in the S band (2 - 4 GHz), leaving open the possibility of experimenting with new forms coming from different equations. For the construction and measurement of the antenna, a FR4 substrate with a dielectric constant ${\varepsilon_{r}}=4.4$ a thickness $\boldsymbol{h}=1.5\boldsymbol{mm}$ , and a tangent of losses of ${\delta}=0.02$ is used. The obtained antenna has an omnidirectional radiation pattern with small variations, an impedance that allows the coupling to $50{\Omega}$ and losses by return below the −10dB. This model has two resonance frequencies within the S Band in 2,4GHz and 3,6GHz with bandwidth of 200MHz and 500Mhz respectively.

For several years the use of Information and Communication Technologies (ICT) has been questioned as a reason to diminish the social interaction between people. Although, it is not possible to remove ICT from our lives as we depend on them in many aspects, we can adapt them so that their use allows us to improve our social skills. This is the case of the Human-Computer Interface (HCI) and, especially those that involve emotions in a communication with machines similar to human interaction between peers. In this article, the implementation of an HCI based on an intelligent virtual agent is presented, with the possibility of learning basic information about the interlocutor and maintaining a short interaction on topics of general interest. The implementation was made in open-source software, generating not only a tool, but a development platform for other people to make contributions. The virtual agent was evaluated through short sessions with university students, who, according to a survey conducted, showed their acceptance of the interaction process.

In this letter, a new Self-Adaptive Whale Optimization Algorithm (SA WOA)is introduced and applied to the design of a printed antenna with ultra wide band (UWB)characteristics. This algorithm is implemented on a basic structure of an octagonal printed antenna which includes a search process based on finding an optimal solution for the effective length of a H-Shaped Notch filter located in the patch. The filter position in conjunction with the effective length determines the frequency ranges that will be rej ected and can be adjusted over the entire operational range of the antenna. In this case, it is proposed to rej ect the frequency bands for IEEE 802.11a and WLAN-HIPERLAN / 2 from 5.1 to 5.9 GHz by applying SA WOA, obtaining an effective filter length of approximately 18.6454 mm and positioned around 12.5269 mm from the power line to ensure an optimum rejection with a center frequency of 5.5 GHz. The dimensions for the optimized printed UWn $B$ octagonal antenna are 30 mm ⨯ 35 mm, with a bandwidth of3.1 to 12 GHz and a return loss less than −10 dB throughout the UWB frequency range except in the optimized rejection range. The proposed SA WOA algorithm uses a correlation-based cost function between the fitness agent and a previously defined response pattern, resulting in a shorter computational time to achieve best parameters providing a high structure precision as well as high performance level.

In this paper we present the design and simulation of a self-complementary (SCA)Ultra-Wideband (UWB)antenna. The basic structure of this antenna uses the Fibonacci sequence in the construction of a golden spiral in the first iteration and six hexagonal monopoles are strategically placed in the midpoints of the spiral to maintain the sequence. In addition, the microstrip feed line is partial expanded to implement a notch filter for acquiring ultra-wideband features. The self-complementary sequence engraved in the ground plane allows the smooth current distribution in the radiating patch and the multiple resonant frequencies. In the other hand, the composition and the structure of the proposed antenna guarantees the coexistence of the UWB and WLAN (5.15-5.825 GHz)technologies. The optimized dimensions for this antenna are 30 mm⨯23.3775 mm, with a bandwidth of 2.63 to 11.2 GHz with multiple resonant frequencies at 2.7-3.41-4.14-4.94-6.82-7.98-8.42-9-9.91-10.45 GHz with a VSWR

In this article we present a general review of nature-inspired metaheuristic algorithms with implementations in patch antenna designs. The primary focus is on Genetic Algorithm (GA), Differential Evolution (DE), Particle Swarm Optimization (PSO), Bacterial Foraging Optimization (BFO). New algorithms recently been introduced also are analyzed, such as: Firefly algorithm (FA), Cuckoo Search (CS), Bat algorithm (BA), Social Spider Optimization (SSO) and Spider Monkey Optimization (SMO). Of each algorithm, a summary of significant examples and a flowchart for a quick and easy interpretation are presented. Finally, the common characteristics of algorithms are compared, concluding in a hierarchical classification according to the efficiency of each one to solve the patch antenna problems.