Evaluation of non-parametric identification techniques in second order models plus dead time

In this paper, a set of non-parametric identification techniques are used in order to obtain second order models plus dead time for an underdamped system. Initially, non-parametric techniques were used to identify the system from the temperature data of a coal-heated oven. In this case, the identification techniques proposed by Stark, Jahanmiri-Fallahi and Ogata were used, which require obtaining two or three points of the step response for the system under study. In addition, the Matlab PID Tuner app was used to identify the underdamped system and compare the results with the other methods. The results show that the PID Tuner and the method proposed by Ogata are the ones that best represent the dynamics of the underdamped system, taking into account the values for the integral absolute error (IAE) and the correlation coefficient. With the Stark method an IAE of 181.56 was obtained, while with the PID Tuner the best performance was achieved with an IAE of 21.59. In terms of the results obtained with the cross correlation, the best performance was achieved with the PID tuner and the Stark method. Copyright © 2020 Institute of Advanced Engineering and Science. All rights reserved

Polarización, heterogeneidad política y redes sociales en México: un análisis comparativo de #PresidenteRompaElPacto, #FRENA y #RevocacionDeMandato en Twitter

Una revisión de la investigación acerca de la polarización en redes sociales sugiere que plataformas digitales como Twitter contribuyen a la polarización ideológica al encerrar a los usuarios de ideas afines en cámaras de eco donde no se exponen a información política que desafíe sus opiniones. El estudio prueba este argumento para el caso mexicano utilizando datos recopilados sobre tres eventos clave ocurridos entre 2020 y 2022 (#PresidenteRompaElPacto, #FRENAAA Y #RevocacionDeMandato).  Los datos fueron extraídos a través de la API de Twitter y analizados con herramientas de visualización de redes usando el lenguaje de programación RStudio. Los resultados demuestran que la polarización en línea depende en menor medida de las llamadas cámaras de eco y es más alta cuando la conversación política se encuentra dinamizada por la dimensión ideológica (izquierda-derecha) de los actores políticos y simpatizantes que participan activamente de las redes sociales y filtran los contenidos con una mirada partidaria. Con este resultado, este estudio, además de sumarse al creciente cuerpo de literatura sobre la relación entre las redes sociales y la polarización política, demuestra que la polarización en Twitter es un fenómeno acotado a cierta parte de la ciudadanía

Análise do uso de mídias e criação de comunidades virtuais em torno do caso #Frena no México

The exchange of news on social networks has become a new source of income for the media. In this regard, it is argued that traditional media have had to adapt to the new reality to survive in the new media environment where they compete with news portals. This proliferation of media has allowed citizens to have more options to choose the news of their choice. Under the assumption that voters' preferences for related media affect the editorial lines of the media, the article investigates what type of media, traditional or digital, is more likely to satisfy the demands of readers. To answer this question, data extracted from Twitter about the #Frena case in Mexico is used. The modeling and visualization of the same were done in the RStudio program. The findings suggest that users tend to share media hyperlinks that are ideologically closer to their political beliefs and that digital media are more likely than traditional media to produce content for segmented audiences. These results seek to contribute to empirical research on media and audiences in digital environments.El intercambio de noticias en redes sociales se ha convertido en una nueva fuente de ingreso para los medios de comunicación. Al respecto se argumenta que los medios tradicionales han tenido que adaptarse a la nueva realidad para sobrevivir en el nuevo entorno mediático donde compiten con portales de noticias. Esta proliferación de medios ha permitido que la ciudadanía cuente con más opciones para elegir las noticias de su preferencia. Bajo el supuesto de que las preferencias de los electores por medios afines inciden en las líneas editoriales de los medios, el articulo indaga sobre qué tipo de medios, tradicionales o digitales, es más propenso a satisfacer las demandas de los lectores. Para responder esta pregunta se utilizan datos extraídos de Twitter sobre el caso #Frena en México. El modelamiento y visualización de los mismos fueron hechos en el programa RStudio. Los hallazgos sugieren que los usuarios tienden a compartir hipervínculos de medios que se encuentran ideológicamente más cercana a sus creencias políticas y que los medios digitales son más propensos que los tradicionales a producir contenidos para audiencias segmentadas. Con estos resultados se busca contribuir a la investigación empírica sobre medios de comunicación y audiencias en entornos digitales.A troca de notícias nas redes sociais tornou-se uma nova fonte de renda para a mídia. Nesse sentido, argumenta-se que a mídia tradicional teve que se adaptar à nova realidade para sobreviver no novo ambiente midiático onde compete com os portais de notícias. Essa proliferação da mídia permitiu que os cidadãos tivessem mais opções para escolher as notícias de sua preferência. Partindo do pressuposto de que as preferências dos eleitores por mídias afins afetam as linhas editoriais da mídia, o artigo investiga que tipo de mídia, tradicional ou digital, tem maior probabilidade de atender às demandas dos leitores. Para responder a essa pergunta, são utilizados dados extraídos do Twitter sobre o caso #Frena no México. A modelagem e visualização das mesmas foram feitas no programa RStudio. Os resultados sugerem que os usuários tendem a compartilhar hiperlinks de mídia ideologicamente mais próximos de suas crenças políticas e que a mídia digital é mais propensa do que a mídia tradicional a produzir conteúdo para públicos segmentados. Esses resultados buscam contribuir para pesquisas empíricas sobre mídias e audiências em ambientes digitais

Implementation of a frequency control in a biomass gasifier system

Distributed power generation has grown in popularity in recent years, especially in areas not connected to the national grid. As a result, rural microgrids are becoming more common, involving great potential for energy based on biomass conversion such as gasification. After analyzing distributed power generation facilities in developing countries, the authors found problems with the frequency stability. This paper focuses on solving the problem of frequency control in energy supplied by microgrids based in biomass gasification. For that purpose, the authors have developed a physical model of a downdraft gasifier, this model was used for design a novel strategy for frequency control, which has been based and validated on an existing gasification system, which supplies power to a population in Necoclí (Colombia)

Analysis of energy management and financial planning in the implementation of photovoltaic systems

This paper presents the analysis of energy management and financial planning that is carried out in the design and implementation of photovoltaic systems in urban areas of the city of Barranquilla, Colombia. A questionnaire with a Likert scale and 36 items was designed, which was answered by subjects with managerial functions of the 16 companies dedicated to the implementation of photovoltaic (PV) projects in Barranquilla. The instrument was validated by expert judgment with a reliability of 0.84 with Cronbach’s Alpha. For the analysis of results, techniques of central tendency and variability were used. The results show that energy management in the implementation of PV projects is moderate, indicating that there is no predominant presence of indicators of improvement and energy performance in these projects. Financial planning has a moderate significance, indicating that the financial analysis methods that are being used in these PV systems projects have a basic analysis

Data from multimodal functions based on an array of photovoltaic modules and an approximation with artificial neural networks as a scenario for testing optimization algorithms

This paper presents the data of multimodal functions that emulate the performance of an array of five photovoltaic modules under partial shading conditions. These functions were obtained through mathematical modeling and represent the P–V curves of a photovoltaic module with several local maximums and a global maximum. In addition, data from a feedforward neural network are shown, which represent an approximation of the multimodal functions that were obtained with mathematical modeling. The modeling of multimodal functions, the architecture of the neural network and the use of the data were discussed in our previous work entitled “Search for Global Maxima in Multimodal Functions by Applying Numerical Optimization Algorithms: A Comparison Between Golden Section and Simulated Annealing” [1]. Data were obtained through simulations in a C code, which were exported to DAT files and subsequently organized into four Excel tables. Each table shows the voltage and power data for the five modules of the photovoltaic array, for multimodal functions and for the approximation of the multimodal functions implemented by the artificial neural network. In this way, a dataset that can be used to evaluate the performance of optimization algorithms and system identification techniques applied in multimodal functions was obtained

Data from a photovoltaic system using fuzzy logic and the P&O algorithm under sudden changes in solar irradiance and operating temperature

This article presents the data of a PV system using fuzzy logic and the perturb and observe (P&O) algorithm, under sudden changes in the solar irradiance and the operating temperature of a PV module. The mathematical modeling of the PV module, the dc-dc converter and the fuzzy and P&O controllers were discussed in our previous work entitled “Fuzzy logic based MPPT controller for a PV System” (Algarín et al., 2017) [1]. Data are presented for six cases with different operating conditions: in the first case the two controllers were evaluated for standard test conditions with constant solar irradiance of 1000 W/m2 and constant temperature of 25 °C. In the remaining five cases sudden increases and decreases were made in the operating conditions of the PV module. Finally, the theoretical data of the PV system are presented, which can be used as a reference to analyze the data obtained with the two controllers in the six cases. Data are provided in Supplementary material in Tables 1–7

Implementation of a cost-effective fuzzy MPPT controller on the Arduino board

This paper presents the implementation of a fuzzy controller on the Arduino Mega board, for tracking the maximum power point of a photovoltaic (PV) module; using low cost materials. A dc-dc converter that incorporates a driver circuit to control the turning on and offof the Mosfet transistor was designed. The controller was evaluated in a PV system consisting of a 65 W PV module and a 12 V/55Ah battery. The results demonstrate the superiority of the fuzzy controller compared to the traditional P & O algorithm, in terms of efficiency and oscillations around the operating point

An Analytic Hierarchy Process Based Approach for Evaluating Renewable Energy Sources

Decision-making in energy planning can be approached as a problem of multicriteria decision analysis in which different types of factors are involved. This task must take into account several aspects due to the increasing complexity of social, technological and economic factors. In this context, this paper uses the analytic hierarchy process (AHP) to prioritize a set of criteria, subcriteria and alternatives as a support for decision-making in the process of energy planning with renewable energies for rural areas in the Caribbean region of Colombia. Based on the participation of experts, 5 criteria, 20 subcriteria and 4 alternatives were defined. Using the AHP, the same group of experts was consulted in order to prioritize all aspects. The results showed that the most relevant criteria were the technical with 24.7%. Next were environmental (21.7%), social (19.6%), economic (17.8%) and risk (16.3%). The best renewable energy alternative was solar with 45.3%

DESEMPENHO DE UM SECADOR TÉRMICO DE LODO MOVIDO A BIOGÁS

A via anaeróbia de tratamento de esgotos sanitários vem sendo amplamente empregada nos países da América Latina e Caribe. O biogás, subproduto destes sistemas, é dotado de grande potencial energético por conter metano em sua composição. Outro subproduto oriundo de sistemas de tratamento de esgoto é o lodo, caracterizado por seu elevado teor de umidade e de microrganismos patogênicos, sendo então seu desaguamento e higienização necessários para sua correta destinação. Atualmente, um dos processos de higienização mais empregados por companhias de saneamento é a estabilização alcalina prolongada (EAP). Os grandes entraves envolvendo tal prática dizem respeito a área requerida para tal processo, a necessidade de incorporação de produtos químicos e o tempo necessário de cura do lodo. Isto posto, novas tecnologias de secagem e higienização estão sendo estudadas de modo a melhorar o gerenciamento do lodo em uma ETE. Nesse contexto, o presente trabalho vem relatar um estudo sobre secagem térmica de lodos em um sistema piloto envolvendo o aproveitamento energético do biogás de uma ETE de médio porte. De modo geral, o secador reduziu em aproximadamente 80% a massa dos diferentes tipos de lodos submetidos ao processo de secagem térmica, aumentando a concentração de sólidos totais nesses materiais de (21,23 ± 3,09) % para (82,87 ± 2,94) %. Com um teor médio de metano de aproximadamente (70 ± 15) %, a vazão de biogás utilizada nesse sistema variou, em média, de 13,92 a 16,17 Nm3.h-1. Os valores da demanda energética do secador para remoção de 1 kg de água presente nos diferentes tipos de lodos variaram de 1.195,18 a 1.597,75 kcal. Adicionalmente, as características físico-químicas, sanitárias e calorimétricas dos lodos após o processo de secagem evidenciaram a possibilidade da utilização desses materiais como adubo na agricultura, bem como no aproveitamento energético devido ao aumento dos seus poderes caloríficos. Esses resultados apontam a secagem térmica do lodo, utilizando biogás produzido em sistemas anaeróbios de tratamento, como uma promissora ferramenta para a sustentabilidade no setor de esgotamento sanitário