Papers by demostenes zegarra rodriguez
Selection of Beamforming in 5G MIMO scenarios using Machine Learning approach
2022 19th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology (ECTI-CON)
PLOS ONE, 2022
Inter-satellite optical wireless communication (Is-OWC) links can become promising solutions to r... more Inter-satellite optical wireless communication (Is-OWC) links can become promising solutions to realize the next-generation high-speed communication services. The operation of Global Navigation Satellite Systems can be improved with the use of Is-OWC links through ranging and communication services. However, the key challenge in Inter-satellite link (ISL) is its effective range which is limited due to pointing errors. In this work, we propose to develop a high-capacity and long-reach Is-OWC link by incorporating hybrid mode division multiplexing (MDM) and wavelength division multiplexing (WDM) schemes to transmit ten independent channels over 40000kms Is-OWC link. Each channel is capable of carrying 400Gbps data which is encoded by the dual polarization quadrature phase shift key technique with required signal to noise ratio (SNR) and received power. The proposed Is-OWC link satisfies the enhanced communication within Geostationary Earth Orbit (GEO) and Low Earth Orbit (LEO) satelli...
Calculating the Influence of Tagging People on Sentiment Analysis
2018 26th International Conference on Software, Telecommunications and Computer Networks (SoftCOM), 2018
Social media makes it possible for anyone to share and transmit their opinions and sentiments to ... more Social media makes it possible for anyone to share and transmit their opinions and sentiments to the rest of the world via the Internet. Recently, sentiment analysis is being used to investigate the opinions posted on Online Social Networks(OSN) based on multiple inputs, such as user profile characteristics, slang, emoticons, among others. However, the current sentiment analysis tools do not consider the influence of tagging people on OSN. In this context, this paper analyzes the impact of the tagging parameter on the global sentiment score of a text. The experimental results of subjective tests show that a correction factor must be considered in case of tagging people. Experimental results demonstrate that the tagging parameter affects the sentiment intensity value, in different ways, depending on the gender of the person who wrote the text and the sentiment polarity of the text. The new sentiment intensity metric considering the tagging people parameter reaches a Pearson Correlation Coefficient of 0.93 and a maximum error of 0.07, for texts of negative polarity written by women, at a 5-point scale. Furthermore, a mobile application with the new sentiment metric, which considers the tagging parameter, is built.
Reconfigurable Intelligent Surfaces Enabling Future Wireless Communication
2021 Third South American Colloquium on Visible Light Communications (SACVLC), 2021
Reconfigurable Intelligent Surface (RIS) has been considered as a promising technology that provi... more Reconfigurable Intelligent Surface (RIS) has been considered as a promising technology that provides ultra-high speed for 5G beyond (5GB) and future 6G wireless communication systems. An RIS has boosted the concept of Smart Radio Environment (SRE) to enable Massive Connectivity with Massive MIMO System. RIS and Massive MIMO are both key enablers at the infrastructural level while millimeter wave (mm-Wave) and Tera Hertz (THz) communication are the key enablers at spectrum level for 5G and 6G. In this article, we discuss some potential candidate technologies and applications using mm-Wave Massive MIMO that can be well equipped with RIS in order to play a vital role in future wireless communication. The applications include Unnamed Aerial Vehicle and Visible Light Communications (VLC). In particular, we discuss and provide insights for VLC technology using RIS. As far as we know, these novel technologies have not been discussed and analyzed in a joint manner so far.
Análise afetiva de frases extraídas das redes sociais
As Redes Sociais atuais estao repletas de informacoes sobre todo e qualquer assunto, as pessoas e... more As Redes Sociais atuais estao repletas de informacoes sobre todo e qualquer assunto, as pessoas expressam suas opinioes e consequentemente sentimentos em cada frase postada ou compartilhada. Este capitulo pretende mostrar ao usuario a importância de se compreender e estudar a analise de sentimentos e tambem a analise afetiva de uma pessoa a fim de extrair informacoes, criticas e sugestoes implicitas e explicitas nos comentarios das pessoas nas Redes Sociais. As Redes Sociais e um ambiente rico de informacoes e neste mini-curso mostraremos conceitos, funcionamento e exemplos de casos de uso, comprovando a utilidade atual da analise afetiva das frases das pessoas contidas na Internet.
Monitoring and Classification of Emotions in Elderly People
2019 International Conference on Software, Telecommunications and Computer Networks (SoftCOM), 2019
Daily, people have access to various multimedia content, that can change their emotional state an... more Daily, people have access to various multimedia content, that can change their emotional state and it can cause an increase in their heart rate. These emotional changes are troubling in the elderly people. Thus, this work aims to classify emotions by machine learning and monitor the emotions of the elderly through the measurement of heart rate, using portable sensors of low cost and easily to use. For this, a framework is implemented, which presents to the user messages of attention and danger according to emotion and heart rate when video contents are presented to the elderly people. Also, the audio transcription of the videos are performed and the sentiment analysis is performed. Thus, when detecting a sudden increase in heart rate and the video presents a negative sentiment polarity, then the proposed solution presents a video of calm or happy content, according to the user's pre-registered preference. The experimental results showed that the classification system performed by a deep learning model obtained values of 97% of accuracy for classifying the disgust emotion and the heart rate level decreased with the proposed framework. Additionally, 93.75% of the users considered the system efficient.
Journal of communications software and systems, 2020
Current implementations of 5G networks consider higher frequency range of operation than previous... more Current implementations of 5G networks consider higher frequency range of operation than previous telecommunication networks, and it is possible to offer higher data rates for different applications. On the other hand, atmospheric phenomena could have a more negative impact on the transmission quality. Thus, the study of the transmitted signal quality at high frequencies is relevant to guaranty the user ́s quality of experience. In this research, the recommendations ITU-R P.838-3 and ITU-R P.676-11 are implemented in a network scenario, which are methodologies to estimate the signal degradations originated by rainfall and atmospheric gases, respectively. Thus, speech signals are encoded by the AMR-WB codec, transmitted and the perceptual speech quality is evaluated using the algorithm described in ITU-T Rec. P.863, mostly known as POLQA. The novelty of this work is to propose a non-intrusive speech quality classifier that considers atmospheric phenomena. This classifier is based on ...
The use of the Prototyping Platform Arduino has been very used in automation projects. In this st... more The use of the Prototyping Platform Arduino has been very used in automation projects. In this study, the Arduino was used in classes of electronic laboratory. The purpose of the project is facilitating the students' learning with the use of a simple and didactic prototype and at the end of the course, to evaluate the knowledge of undergraduate students. Prior to the use of Arduino, other traditional electronic components were used in the laboratory to verify if the use of Arduino facilitated the learning in laboratory classes. The results showed that the use of Arduino facilitated the achievement of theoretical concepts by 30% compared to the use of traditional teaching modules for electronic.
Nowadays, recognition patterns play an important role in several applications, in which the iris ... more Nowadays, recognition patterns play an important role in several applications, in which the iris recognition is widely developed in authentication systems today. For such systems models, it is necessary to use as input high quality images, which will reduce possible recognition errors. Thus, this article develops experimental tests to study the image quality on the performance of the iris recognition, using different quality metrics. Thus, experiments are conducted with different iris images and applying the Hamming distance algorithm as reference measurement to accept or denied an user authentication. To this end the OSIRIS platform was used in the tests, because it permits to calculate the Hamming Distance between two binary codes. Based on the results obtained in the tests using different metrics, can be inferred that the image quality has a considerable impact on the performance of an iris recognition system. Therefore, the image capture process is an important step. Resumo: Atu...
Energiesparvorrichtung und -verfahren in einem ad-hoc-netzwerk
Telecommunications services monitoring is of paramount importance, network operators must meet th... more Telecommunications services monitoring is of paramount importance, network operators must meet the expectations of their subscribers. On wireless communications, transmitted signal may suffer different degradations in the transmission channel. In the literature, there are different models of wireless channels, among the most cited are the Rician and Rayleigh fading channel models, each one presents different characteristics of transmission. In the speech quality assessment research area, most of the works focused on wired network type degradations, using parameters as packet losses, delay and jitter; however, wireless degradation characteristics are not considered. In this context, the present paper investigate the impact of different Doppler frequency shifts (Hz) on speech communications, using the fading channel models previously mentioned, and different multipath delay profiles. Performance evaluation parameters are based on the voice quality assessment algorithms described in re...
Impact of FEC codes on speech communication quality using WB E-model algorithm
2019 Wireless Days (WD), 2019
In current communication systems, forward Error Correction (FEC) codes are used to decrease the i... more In current communication systems, forward Error Correction (FEC) codes are used to decrease the information losses in the transmission channel to improve the signal quality in the reception point. The speech quality is affected by many factors being packet losses one of the most important. Currently, there are different speech quality assessment methods; for planning purposes, E-model algorithm is the most representative. However, it does not consider wireless network characteristics and techniques. Based on this fact, the main contribution of this work is to adapt the wide-band (WB) E-model algorithm to be able to evaluate the impact of FEC codes on speech quality. For this purpose, a function named GFECx(Ms,SNR) is proposed that quantifies the quality gain reached by FEC codes at different wireless channel conditions. This function is inserted into Ie,eff,WB impairment factor of the WB E-model algorithm. Experimental results demonstrated that the proposed solution gets a high corr...
Quantifying the Quality Improvement of MIMO Transmission Systems in VoIP Communication
2018 26th International Conference on Software, Telecommunications and Computer Networks (SoftCOM), 2018
Currently, Voice over IP (VoIP) communication service is widely used mainly because its lower cos... more Currently, Voice over IP (VoIP) communication service is widely used mainly because its lower cost. However, the quality of a VoIP communication is lower than a fixed-line communication due to network degradations. In this context, the objective of this work is to evaluate the quality of voice communications that undergo degradations in the wireless interface, and how MIMO technology helps to improve the voice signal quality. For this, a simulator named WVoIPSim is built, in which different modulation schemes, an error correction coding and different noise levels in wireless channel are implemented. The resulting speech signal, at the receiver, is analyzed by the ITU-T Recommendations P.862 and P.563, in which P.862 is used as reference. Experimental results show that there is a high correlation between MIMO system configurations and speech quality scores. Based on these results, different MIMO configurations for different network conditions is proposed in order to guarantee a MOS score higher than 4.0.
Improving a Parametric Model for Speech Quality Assessment in Wireless Communication Systems
2018 26th International Conference on Software, Telecommunications and Computer Networks (SoftCOM), 2018
Telecommunication operators need tools to evaluate and improve the quality of the their services ... more Telecommunication operators need tools to evaluate and improve the quality of the their services offered. In the case of telephony services, the speech quality perceived by the users is relevant. There are different speech quality assessment methods, one of them is the parametric method that is generally used in network planning. The ITU-T Rec. G107, and its recent updates, is the most representative parametric method. However, it does not consider the impairments occurred in a wireless channel. In this context, we propose the inclusion of parameters, such as fading channel model, signal-to-noise ratio (SNR), and maximum Doppler shift using different modulation schemes. Several wireless communication scenarios were simulated using actual speech samples as input. Then, the impairment speech samples were evaluated by an intrusive signal-based method described in ITU-T Rec. P.862.2, which results are used as ground-truth. Experimental results demonstrated that there is a high correlation between wireless channel parameters and mean opinion score (MOS) index. Thus, an impairment wireless function, namedIw is proposed and added to the E-model wide-band algorithm. Performance validation test results demonstrated thatIw represents a reliable wireless degradation model, reaching a Pearson correlation coefficient (PCC) and a normalized RMSE (NRMSE) of 0.973 and 0.085, respectively.
Sensors, 2020
Minimizing human intervention in engines, such as traffic lights, through automatic applications ... more Minimizing human intervention in engines, such as traffic lights, through automatic applications and sensors has been the focus of many studies. Thus, Deep Learning (DL) algorithms have been studied for traffic signs and vehicle identification in an urban traffic context. However, there is a lack of priority vehicle classification algorithms with high accuracy, fast processing, and a lightweight solution. For filling those gaps, a vehicle detection system is proposed, which is integrated with an intelligent traffic light. Thus, this work proposes (1) a novel vehicle detection model named Priority Vehicle Image Detection Network (PVIDNet), based on YOLOV3, (2) a lightweight design strategy for the PVIDNet model using an activation function to decrease the execution time of the proposed model, (3) a traffic control algorithm based on the Brazilian Traffic Code, and (4) a database containing Brazilian vehicle images. The effectiveness of the proposed solutions were evaluated using the ...
Anais do XXXVI Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos (SBRC 2018), 2018
As aplicações de streaming multimídia têm crescido imensamente nos últimos anos e vêm sendo estud... more As aplicações de streaming multimídia têm crescido imensamente nos últimos anos e vêm sendo estudadas com a finalidade de garantir uma boa QoE para o usuário. Entretanto, poucos trabalhos preocupam-se com o consumo de energia e com as características do conteúdo multimídia de forma profunda, o que torna o consumo energético por parte desses conteúdos umaárea obscura. Neste artigo apresenta-se um modelo matemático que sugere como é o consumo em Ah de um vídeo em função de seus parâmetros. O modelo proposto foi um arquétipo exponencial, mostrando-se bem próximo do modelo real, descrevendo quais propriedades têm mais influência no consumo, devendo ser aplicado aos vídeos com taxa de bits constante.
IEEE Access, 2021
Currently, with the increasing number of devices connected to the Internet, search for network vu... more Currently, with the increasing number of devices connected to the Internet, search for network vulnerabilities to attackers has increased, and protection systems have become indispensable. There are prevalent security attacks, such as the Distributed Denial of Service (DDoS), which have been causing significant damage to companies. However, through security attacks, it is possible to extract characteristics that identify the type of attack. Thus, it is essential to have fast and effective security identification models. In this work, a novel Intrusion Detection System (IDS) based on the Tree-CNN hierarchical algorithm with the Soft-Root-Sign (SRS) activation function is proposed. The model reduces the training time of the generated model for detecting DDoS, Infiltration, Brute Force, and Web attacks. For performance assessment, the model is implemented in a medium-sized company, analyzing the level of complexity of the proposed solution. Experimental results demonstrate that the proposed hierarchical model achieves a significant reduction in execution time, around 36%, and an average detection accuracy of 0.98 considering all the analyzed attacks. Therefore, the results of performance evaluation show that the proposed classifier based on Tree-CNN is of low complexity and requires less processing time and computational resources, outperforming other current IDS based on machine learning algorithms.
Anais de XXXIII Simpósio Brasileiro de Telecomunicações, 2015
In a voice-over-IP (VoIP) communication there are different factors that degrade the voice signal... more In a voice-over-IP (VoIP) communication there are different factors that degrade the voice signal quality, and these degradations need to be evaluated in real time. In this scenario, the non-intrusive metrics such as the ITU-T P.563 recommendation are the most indicated. However, this metric has not a suitable performance if compared with intrusive metrics. In this study, an adjustment function is proposed to improve the P.563 metric's performance considering the packet loss parameter. The results show that the performance in relation to ITU-T P.862 was improved, obtaining a Pearson-correlationcoefficient and a maximum error of 0.99 and 0.40, respectively.
Anais de XXXIII Simpósio Brasileiro de Telecomunicações, 2015
Resumo-Este artigo apresenta um estudo de como os parâmetros intrínsecos de um sinal de voz, como... more Resumo-Este artigo apresenta um estudo de como os parâmetros intrínsecos de um sinal de voz, como o Short-Time Energy (STE) e o Short-Time Zero Crossing Rate (STZCR) estão relacionados com a qualidade de uma comunicação de voz sobre IP, que sofre perdas de pacotes no canal de transmissão.
New business models and the sharing economy: impacts and challenges for the traditional automotive industry
International Journal of Automotive Technology and Management, 2019
The outstanding features of a vehicle do not include great modifications for nearly 100 years, as... more The outstanding features of a vehicle do not include great modifications for nearly 100 years, as the same to the major car manufacturers' business models (BM). Recent service's platforms related to urban mobility use, mostly, the sharing economy, resulting in disruptive innovations. This offer to the users new experiences in services (e.g., Uber) which provides the vehicle's use without the onus of ownership. From this perspective, this paper qualitatively evaluates the modifications in the automakers BM's standards based on strategies and innovations of the new businesses of the main groups of automotive manufacturers. As a result, we observed that traditional products-based automakers are already moving towards to fit in the new BM, which are impacted by the sharing economy. Finally, we proposed a framework based on an unbundled model operating synergistically in three types (customer relationship management, product/service innovation and infrastructure management).
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Papers by demostenes zegarra rodriguez