Álgebra óptima y soluciones invariantes para la ecuación de Chazy

Se caracterizan las soluciones invariantes para la ecuación de Chazy a partir de los operadores generadores del álgebra óptima, la cual fue obtenida mediante el grupo de simetrías de Lie correspondiente a dicha ecuación.

Inference in Multiple Linear Regression Model with Generalized Secant Hyperbolic Distribution Errors

We study multiple linear regression model under non-normally distributed random error by considering the family of generalized secant hyperbolic distributions. We derive the estimators of model parameters by using modified maximum likelihood methodology and explore the properties of the modified maximum likelihood estimators so obtained. We show that the proposed estimators are more efficient and robust than the commonly used least square estimators. We also develop the relevant test of hypothesis procedures and compared the performance of such tests vis-a-vis the classical tests that are based upon the least square approach.

Experimental Development of Fuzzy Controllers for Thermal and Pneumatic Processes

In this project, a Fuzzy control system is proposed in an industrial process training module with two independent systems between them, one thermal and the other pneumatic. The control algorithm is developed in Python language v3.6 executed by a Raspberry Pi B+, both controllers depend on the error and change in error that are updated in times of 2 s and 1 s, for temperature and pressure respectively, communication with the plants uses A/D and D/A converters, the thermal Fuzzy was analyzed with three temperature references [50,100 and 150]°C, with a rise time of 191 s, 360 s and 505 s; steady state error of 5.5%, 0.7% y 0.7%, in the pneumatic system the speed of change between references is evaluated from 10 psi to 15 psi varying the activation of the compressor at the beginning of the experiments, the settling times obtained are 111 s and 106 s, with the compressor off the result is 116 s and 88 s, besides a maximum excess of 13% with inherent oscillations to the type system that are in an acceptable range.

Sizing of Hybrid Photovoltaic-Wind Energy Systems Based on Local Data Acquisition

Although there are different alternatives to provide energy, there are still remote regions with no nearby possibilities of having an electricity supply that meets their basic needs. Colombia, like many countries, does not have uniform environmental conditions; therefore, applying models for the dimensioning of energy systems based on renewable energy can be inefficient and expensive, making it difficult to access electricity in isolated places. The research aims to develop a sizing strategy for a hybrid system based on locally acquired environmental information to size a system that takes advantage of the natural resources available in the local in the best possible way. Information is collected through a data acquisition system on local environmental conditions, system requirements are established based on energy demand, and a mathematical model is sought that represents the electrical behavior. The model makes it possible to analyze the system’s behavior under variable environmental conditions in the region, thus guaranteeing an adequate dimensioning for a constant supply of low-power energy suitable for residential use. This article presents an alternative to characterize a hybrid power generation system (photovoltaic/wind turbine) through data collected on-site, which, when properly processed, allows the dimensioning of a more appropriate hybrid system to the environmental conditions the environment. The system was implemented in an experimental farm of the University of Pamplona located in the north of Colombia. Based on this strategy, a hybrid system was designed and installed to meet energy demands efficiently.

e— Cálculo

En este trabajo se formula el e— cálculo en base a la naturaleza de las cargas eléctricas, usando la tercera ley de Newton y la ley de Coulomb, la e— álgebra y la q — e álgebra deformada, asociando las variables ei; ej como cargas elementales, y x como la variable conductora. Se define la e— derivada a partir de un simple experimento de encendido y apagado de un bombillo respectivamente. Por otro lado, se formulan las e— series, la e— integral, las q — e derivadas, series e integrales y sus respectivos criterios de convergencia. Sobre las e— integrales se establecen un camino o contorno cerrado Γ (x) para definir las e— integrales de contorno, y finalmente se formulan el q — e cálculo deformado y la q — e álgebra de Heisenberg.

Inference in Multiple Linear Regression Model with Generalized Secant Hyperbolic Distribution Errors

We study multiple linear regression model under non-normally distributed random error by considering the family of generalized secant hyperbolic distributions. We derive the estimators of model parameters by using modified maximum likelihood methodology and explore the properties of the modified maximum likelihood estimators so obtained. We show that the proposed estimators are more efficient and robust than the commonly used least square estimators. We also develop the relevant test of hypothesis procedures and compared the performance of such tests vis-a-vis the classical tests that are based upon the least square approach.

Calidad del aire en el Valle de Aburrá, ¿Qué podríamos esperar de la ciudad inteligente?

El fenómeno global de crecimiento urbano, unido a la rápida penetración de la telefonía móvil, internet de las cosas, sensórica, automatización, intercambio de datos en tiempo real, etc, confluyen en un tema que genera grandes expectativas: la ciudad inteligente. Entre sus múltiples implicaciones, en este texto se destacan hechos relevantes para la gestión de la calidad del aire en el Valle de Aburrá. El punto de partida es Plan de Gestión de la Calidad del Aire para el Valle de Aburrá, con vigencia 2017-2030. Se presenta una correlación entre las oportunidades de gestión que la ciudad inteligente ofrece a la calidad del aire y las líneas estratégicas de dicho plan. Se identifican importantes soluciones desde el enfoque bottom-up, centradas en el uso masivo de la información y la apropiación de herramientas digitales para favorecer la autogestión de las emisiones en todos los ámbitos – fuentes fijas y móviles, públicas y particulares.

Propuesta de un dispositivo refrigerante con celdas Peltier alimentado con un sistema fotovoltaico independiente: un caso de estudio

Actualmente, múltiples estudios intentan establecer alternativas que permitan disminuir las consecuencias del gasto energético y los gases de efecto invernadero. En este sentido, la energía solar fotovoltaica se ha convertido en una opción factible para aplacar esta problemática, asimismo, se han buscado nuevas tecnologías para disminuir el gasto energético de los dispositivos refrigerantes, porque consumen emasiada energía y utilizan refrigerantes dañinos para cumplir su tarea. Por esta razón, las celdas Peltier pueden ser una opción viable para disminuir la temperatura en espacios cerrados sin generar residuos o emisiones nocivas. En el presente trabajo se plantea combinar estas iniciativas en un sistema unificado para aprovechar ambas tecnologías, implementando un sistema refrigerante que utiliza el efecto termoeléctrico para reducir la temperatura en su interior, que es alimentado por un sistema fotovoltaico autónomo utilizando algoritmos de seguimiento del punto de máxima potencia para mejorar su rendimiento. Los resultados reflejan que el dispositivo es capaz de disminuir la temperatura en su interior, permitiendo la conservación de elementos a temperaturas bajas y constantes, sin los inconvenientes de los refrigeradores comunes. Finalmente, se concluye que este sistema es una posibilidad plausible para sustituir las tecnologías de enfriamiento donde el acceso a la energía eléctrica es limitado.

Landslide Susceptibility Assessment Using the Scoops3D Model in a Tropical Mountainous Terrain

Many physically-based distributed models study the landslide occurrence using an infinite slope stability analysis, simulating a planar failure, which is not usually applicable to rotational failures and deep landslides. Recently, some three-dimensional distributed physically-based models have been developed that have been applied in different parts of the world. In this research, the Scoops3D model is implemented for a landslide susceptibility analysis in a tropical mountainous terrain of the Colombian Andes (Medellín, Colombia). In addition to identifying the areas susceptible to the occurrence of rotational landslides, the results of the safety factor are analyzed with the areas of associated critical failure surfaces to provide an interpretation and explanation of the simulation results. This is to have a better understanding of how the model works and to facilitate its implementation in landslide hazard assessment. The Scoops3D physicallybased model can be a very useful tool for mass movement risk management projects.

A Predictive Model for the Anisotropy Index of Semi-Coke Derived from the Properties of Colombia's Eastern Cordillera Coals

This study developed a theoretical model for the determination of the Coke Anisotropy Quotient (CAQ) of semi-coke from the properties of its precursor coal. This is an useful parameter to define the resistance and reactivity of semi-coke in the blast furnace. For 36 semi-coke samples, a textural analysis was performed alongside a fluidity test to determine the real CAQ. The main textures observed were: isotropic and circular for high volatile bituminous coals (HVB); lenticular and fine ribbons for the medium volatile bituminous coals (MVB); and medium and thick ribbons for the low volatile bituminous coals (LVB). The CAQ varied in a range from 1 to 11. A principal component analysis (PCA) and multiple regression allowed to discriminated the importance of certain coal properties, in determining the CAQ to be recognized and to estimate parameters of the mathematical model. The statistical analysis suggested that CAQ can be best predicted from the fluidity, volatile matter, and Ro of the parent coals. The veracity of this model result was then tested using a second dataset from Poland. This work optimizes the usefulness of standard datasets in the prediction of CAQ's offering a means of quality control that could be implemented in Colombian coke production.