Universidad Tecnológica de Bolívar
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Land-Use Dynamics and Water Quality in Andean Basins
No full textConventional agricultural practices, such as the use of agrochemicals, implementation of monocultures, and the expansion of crops in strategic ecosystems, have significant impacts in Andean basins, directly increasing nutrient inputs to waterways, and contributing to ecological fragility and socioeconomic vulnerability. This complex dynamic is related to land-use change and production activities that affect the provision of hydrological ecosystem services. This study presents an integrated analysis of socioecological interactions related to water quality in the Las Piedras River basin (LPRB), a water supply basin located in the Andean region of southwestern Colombia. The analysis was conducted over a five-year monitoring period to assess the spatiotemporal variation and correlation of water quality between streams and agricultural runoff water within the LPRB. Furthermore, water quality indices were calculated based on physicochemical and biological parameters to evaluate the impact of land-use/land-cover changes and agricultural activities within the basin. Results demonstrate that different types of actors, productive logics, mechanisms of use, and access to water within the basin affect water quality and uncertainty for water management, while facing socioecological conflicts between actors
Application of the Multiverse Optimization Method to Solve the Optimal Power Flow Problem in Alternating Current Networks
No full textIn this paper, we solve the optimal power flow problem in alternating current networks to reduce power losses. For that purpose, we propose a master–slave methodology that combines the multiverse optimization algorithm (master stage) and the power flow method for alternating current networks based on successive approximation (slave stage). The master stage determines the level of active power to be injected by each distributed generator in the network, and the slave stage evaluates the impact of the proposed solution on each distributed generator in terms of the objective function and the constraints. For the simulations, we used the 10-, 33-, and 69-node radial test systems and the 10-node mesh test system with three levels of distributed generation penetration: 20%, 40%, and 60% of the power provided by the slack generator in a scenario without DGs. In order to validate the robustness and convergence of the proposed optimization algorithm, we compared it with four other optimization methods that have been reported in the specialized literature to solve the problem addressed here: Particle Swarm Optimization, the Continuous Genetic Algorithm, the Black Hole Optimization algorithm, and the Ant Lion Optimization algorithm. The results obtained demonstrate that the proposed master–slave methodology can find the best solution (in terms of power loss reduction, repeatability, and technical conditions) for networks of any size while offering excellent performance in terms of computation time. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
Labour Informality in Colombia's 13 Cities and Metropolitan Areas between 2019-2020
No full textLabour informality has major relevance on the world economy and Colombia is no exception; historically the country has been characterised by elevated rates of informality related to poverty indicator variables. The purpose of the document is to analyse this relation in the 13 main cities and metropolitan areas of Colombia, in the context of the COVID-19 pandemic. With this objective, the study performs a simple correlation analysis and a probit model that measures the impact of the variables that integrate the Multidimensional Poverty Index (MPI) and socio-demographic variables (age and gender) on the probability of being informally employed. The results expose that Monetary Poverty is the variable that has the most impact in this probability. Finally, this document highlights the importance of reducing informality in order to advance in the achievement of the national goals related to The 2030 Agenda for Sustainable Development. © 2022, Universidad de Huelva. All rights reserved
Full State Feedback of DC-Motor Position and Speed Control Using LQR and Kalman Filter
No full textDC motors are used in various industrial, robotic and motion control applications, and generally angular position and speed are used as the main control variables. This paper presents the design of an LQR controller with a Kalman Filter (KF) for state estimation during position and speed control of a DC motor. The proposed controller is evaluated for low and high speed reference profiles to demonstrate its efficiency in different types of applications. This approach is compared with the classical control method using a PID controller. From the results, it is observed that the settling time of the LQR-KF method is less, being 30% more efficient than the PID. In addition, the use of LQR provides an optimal state feedback control that minimizes the quadratic state error and control effort. The experimental results demonstrate the feasibility of the controller design for high precision applications. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG
Love Thy Neighbor: La Vida Musical De Justo Almario
No full textJusto estaría tocando con un quinteto igual en cuanto al formato, solo que con otros nombres. Haciendo un paralelo, Justo tomaría el lugar de John Coltrane. Tocar con Kenny lo entendía como la culminación de un sueño: el sueño de tocar jazz con y como los grandes del jazz. Escuchemos, en sus propias palabras, qué significó para Justo hacer parte de la agrupación de Kenny Burrell
a participación ciudadana en fiestas populares del Caribe colombiano: análisis cuantitativo del Carnaval de Barranquilla y las Fiestas de Independencia de Cartagena
No full textThe research analyzes the citizen participation in cultural activities, in particular, in the most popular celebrations in the Colombian Caribbean region, the Carnival of Barranquilla Carnival and the Independence Feasts of Cartagena, whose historical links and evolution have been decisive in the construction of the regional festive memory. The approach and method of Cultural Economics are used to identify and compare the factors associated with local participation during the last decade, and Como Vamos programs’ surveys are used to empirically evaluate the role of a set of traditional variables and the local context in the decision to participate in these festivals. The results suggest wide gaps between and within cities, which are explained by variables such as cultural capital, gender and leisure time, and others considered as structural, such as socioeconomic status, poverty and place of residence. Inequities are substantially greater in Cartagena, where it is necessary to expand access to the most lagging population. The article offers a new standpoint on the nature of regional feast and festivals and inputs for designing cultural policies to greater social appropriation of the regional intangible heritage. © 2022 Universidad del Norte. All rights reserved
Performance evaluation of mechanical engineering degrees using partial minimum squares and data envelopment analysis
No full textThis study analysed the causal relationship between the learning outcomes acquired in high school and university by mechanical engineering students in Colombia. The methodology articulates partial least squares and data envelopment analysis. The data represents the standardised exams conducted by the Colombian Institute for the Quality of Education from 2012 to 2019. The results indicate that 42% of the degrees that receive students with high levels of high school knowledge cannot add value to higher education learning outcomes. In parallel, 21% of the programs that receive students with low academic performance in high school can reach high-performance learning outcomes in higher education. In conclusion, the present methodology contributes to the spectrum of knowledge of models that support decision-making in the educational field to focus on improving academic levels and educational qualit
Repensando a abrangência da informação ambiental a partir da Agenda-Setting e a função normativa dos atributos
No full textExaminamos los atributos sustantivos y afectivos dominantes en 358 noticias relacionadas con la gestión del agua y los residuos en Colombia durante cinco años. Los resultados revelaron que los textos estudiados se centraron más en la existencia de atributos de los problemas ambientales y en las emociones positivas relacionadas con buenas prácticas de gestión, que en los efectos y soluciones. Estos resultados analizan cómo la teoría de la Agenda-Setting puede proporcionar una guía práctica para que los periodistas replanteen su cobertura informativa ambiental desde una perspectiva normativa.We examined the dominant substantive and affective attributes in 358 news items related
to water and waste management in Colombia over five years. The results revealed that
the studied texts focused more on the existence of attributes of environmental problems
and on positive emotions related to good management practices, than on the effects
and solutions. These results explore how Agenda-Setting theory can provide practical
guidance for journalists to rethink their environmental coverage from a normative
perspective.Examinamos os atributos substantivos e afetivos dominantes em 358 notícias relacionadas
à gestão de água e resíduos na Colômbia durante cinco anos. Os resultados revelaram
que os textos estudados enfocam mais a existência de atributos dos problemas ambientais
e emoções positivas relacionadas às boas práticas de gestão do que os efeitos e soluções.
Esses resultados exploram como a teoria do Agenda-Setting pode fornecer orientação
prática para os jornalistas repensarem sua cobertura ambiental de uma perspectiva
normativa.Universidad Tecnológica de Boliva
Application of the arithmetic optimization algorithm to solve the optimal power flow problem in direct current networks
No full textThis article presents a methodology to solve to the Optimal Power Flow (OPF) problem in Direct Current (DC) networks using the Arithmetic Optimization Algorithm (AOA) and Successive Approximation (SA). This master-slave methodology solves the OPF problem in two stages: the master stage estimates the solution to the OPF problem considering its constraints and variables, and the slave stage assesses the fitness of the solution proposed by the master stage. To validate the methodology suggested in this article, three test systems cited multiple times in the literature were used: the 10, 21 and the 69 nodes test systems. In addition, three scenarios varying the allowable power limits for the Distributed Generators (DGs) are presented; thus, the methodology explores solutions under different conditions. To prove its efficiency and robustness, the solution was compared with four other methods reported in the literature: Ant Lion Optimization (ALO), Black Hole Optimization (BHO), the Continuous Genetic Algorithm (CGA), and Particle Swarm Optimization (PSO). The results show that the methodology proposed here to reduce power losses presents the best solution in terms of standard deviation. © 2022 The Author
Posicionamiento y estado de las revistas numismÁticas EspaÑolas en bases de datos cientÍficas
No full textThe following article captures the current situation of the Spanish scientific journals focused on numismatics and their positioning in the main international bibliographical (Latindex, Web of Science and Scopus) and Spanish databases (Dialnet and CIRC) through a comparative analysis of their distinctive characteristics and fundamental metrics (Google Scholar H5 index and their scores in MIAR). The results obtained determine that within this group has excelled in a prominent place the Revista Numismática Hécate, the only Spanish publication on this subject that has managed to be indexed in high impact databases such as the Web of Science and Scopus