Scientific Computing and the Huygens' Principle

Abstract. Mathematics has been present in the development of society since time immemorial; great figures have dedicated their entire life to analysis and research in various branches of this broad science. Scientific Computing is closely related to the design and construction of mathematical models aimed at solving scientific, social and engineering problems. There are several applications of this discipline, for example for mathematical simulations of differential equations in partial derivatives that describe the propagation of a variety of waves such as sound waves, or heat conduction problems in different media, which can be solved using The Fourier Analysis. Through Graphical Computing the Huygens Principle can be verified. All these models can be implemented through the computer in order to facilitate the complex calculations that must be done to solve problems of this type and depending on the case to condense all this information into a graph "A good graph says more than a thousand words (Chinese Proverb) ". 

Diseño de un sistema de control visual para navegación de interiores usando fusión sensorial para una plataforma móvil diferencial.

El presente trabajo tuvo como finalidad diseñar un Sistema de control visual para navegación de interiores usando fusión sensorial sobre una Plataforma Móvil Diferencial. La investigación se desarrolló acerca de la tecnología Raspberry Pi y su utilización con el software Matlab, el ordenador controla la posición del servomotor ubicando la cámara de 0 a 180 grados, con avances de 45° para realizar una captura del entorno al instante, se realizó las operaciones de erosión y dilatación de las imágenes capturadas y de la base de datos, la finalidad de estas operaciones es obtener de forma clara los contornos de las capturas, para verificar si existe o no un obstáculo, en el sistema de control visual se emplea la correlación de imágenes. Para la verificación del sistema se empleó una tarjeta Arduino Nano con sensores ultrasónicos que permiten detectar si existe un objeto dentro del área de trabajo definida, si los dos sistemas concuerdan en la información sensada el robot toma una decisión en su desplazamiento, accionándose los motores desde el scrip. Para verificar la hipótesis se diseñó el experimento de manera que determine el nivel de eficiencia del sistema de control en diversas pistas que varían en la cantidad de obstáculos y forma de desplazamiento, se consideró el estadístico Anova obteniendo un resultado de 15,62 en el valor calculado de Fisher que comparado con el punto crítico del estadístico es de 9,55 se rechaza la hipótesis Nula, aceptando la hipótesis original de la investigación. Para finalizar se recomienda realizar una investigación para solucionar los errores encontrados en el sistema de control visual debido a los cambios que pueden existir en la luz ambiente, es decir, un sistema de iluminación que se adapte a las condiciones del sistema.The aim of this work was to design a visual control system for interior navigation using sensorial fusion on a Differential Mobile Platform. The research was developed about the Raspberry Pi technology and its use with the Matlab software. The computer controls the position of the servomotor by locating the camera from 0 to 180 degrees with 45° advances to capture the environment instantly. The operations of erosion and dilatation of captured images and of the database were developed, the purpose of these operations is to clearly obtain the contours of the captures in order to verify whether or not there is an obstacle, in the visual system the correlation of images were used. To the verification of the system, an Arduino Nano card with ultrasonic sensors was used to detect if there is an object within the defined work area. If the two systems agree on the sensed information, the robot makes a decision on its displacement, activating the motors from the scrip. To verify the hypothesis, the experiment was designed in such a way that it determines the level of efficiency of the control system in various tracks that vary in the number of obstacles and the form of displacement. The ANOVA statistic was considered obtaining a result of 15.62 in the value calculated from Fisher that compared with the critical point of the statistic is 9.55 the Null hypothesis is rejected, accepting the original hypothesis of the investigation. Finally, it is recommended to carry out an investigation to solve the errors found in the visual control system due to the changes that may exist in the ambient light, that is, a lighting system that adapts to the conditions of the system

Composición de los ensambles de comunidades de murciélagos del Bosque Protector Cerro Blanco, Guayaquil

Los murciélagos pertenecen a uno de los grupos más diversos de mamíferos en el mundo y constituyen un grupo importante dentro de los ecosistemas ya que brindan servicios ambientales como control de plagas, polinización y dispersión de semillas. Las comunidades de murciélagos han sido poco estudiadas en el Ecuador y el monitoreo acústico se ha convertido en una herramienta apropiada para registrar especies que son difíciles de capturar con métodos tradicionales como las redes de neblina. En el presente estudio se evaluó la composición en los ensambles de murciélagos en relación a parches de bosque con distintos grados de disturbio en el área del Bosque Protector Cerro Blanco (provincia del Guayas). Se utilizaron redes de neblina para muestrear las especies de sotobosque y equipos de monitoreo acústico para las especies de vuelo alto en cada uno de los tipos de bosque. Los sitios de muestreo se visitaron por ocho noches consecutivas durante los meses de septiembre a diciembre de 2015. Se realizaron curvas de acumulación, con ajuste de Clench, para evaluar la eficiencia de muestreo y ponderar la riqueza potencial de cada sitio de estudio. Se realizaron análisis de diversidad α para cada sitio de muestreo y un análisis de diversidad β para comparar entre pares de sitios. Se desarrollaron análisis factoriales de correspondencia y curvas de rango-actividad relativa para observar las tendencias poblacionales de las especies que componen cada sitio muestreado. Los resultados mostraron que dos de los parches presentaron una gran diversidad de especies en cada gremio, a pesar de tener distinto grado de disturbio. Adicionalmente el parche que presentó menor diversidad tanto de gremios como de especies fue el más cercano al área urbana, incluyendo menor cantidad de individuos grabados y capturados. Estos resultados muestran que la intervención humana en los bosques afecta de diferentes formas a la composición de especies de una comunidad

Diseño de un sistema de control visual para navegación de interiores usando fusión sensorial para una plataforma móvil diferencial.

El presente trabajo tuvo como finalidad diseñar un Sistema de control visual para navegación de interiores usando fusión sensorial sobre una Plataforma Móvil Diferencial. La investigación se desarrolló acerca de la tecnología Raspberry Pi y su utilización con el software Matlab, el ordenador controla la posición del servomotor ubicando la cámara de 0 a 180 grados, con avances de 45° para realizar una captura del entorno al instante, se realizó las operaciones de erosión y dilatación de las imágenes capturadas y de la base de datos, la finalidad de estas operaciones es obtener de forma clara los contornos de las capturas, para verificar si existe o no un obstáculo, en el sistema de control visual se emplea la correlación de imágenes. Para la verificación del sistema se empleó una tarjeta Arduino Nano con sensores ultrasónicos que permiten detectar si existe un objeto dentro del área de trabajo definida, si los dos sistemas concuerdan en la información sensada el robot toma una decisión en su desplazamiento, accionándose los motores desde el scrip. Para verificar la hipótesis se diseñó el experimento de manera que determine el nivel de eficiencia del sistema de control en diversas pistas que varían en la cantidad de obstáculos y forma de desplazamiento, se consideró el estadístico Anova obteniendo un resultado de 15,62 en el valor calculado de Fisher que comparado con el punto crítico del estadístico es de 9,55 se rechaza la hipótesis Nula, aceptando la hipótesis original de la investigación. Para finalizar se recomienda realizar una investigación para solucionar los errores encontrados en el sistema de control visual debido a los cambios que pueden existir en la luz ambiente, es decir, un sistema de iluminación que se adapte a las condiciones del sistema.The aim of this work was to design a visual control system for interior navigation using sensorial fusion on a Differential Mobile Platform. The research was developed about the Raspberry Pi technology and its use with the Matlab software. The computer controls the position of the servomotor by locating the camera from 0 to 180 degrees with 45° advances to capture the environment instantly. The operations of erosion and dilatation of captured images and of the database were developed, the purpose of these operations is to clearly obtain the contours of the captures in order to verify whether or not there is an obstacle, in the visual system the correlation of images were used. To the verification of the system, an Arduino Nano card with ultrasonic sensors was used to detect if there is an object within the defined work area. If the two systems agree on the sensed information, the robot makes a decision on its displacement, activating the motors from the scrip. To verify the hypothesis, the experiment was designed in such a way that it determines the level of efficiency of the control system in various tracks that vary in the number of obstacles and the form of displacement. The ANOVA statistic was considered obtaining a result of 15.62 in the value calculated from Fisher that compared with the critical point of the statistic is 9.55 the Null hypothesis is rejected, accepting the original hypothesis of the investigation. Finally, it is recommended to carry out an investigation to solve the errors found in the visual control system due to the changes that may exist in the ambient light, that is, a lighting system that adapts to the conditions of the system

Estilo Cognitivo e Estratégias de Aprendizagem em Estudantes Universitários Brasileiros: Repercussões no Rendimento Acadêmico

In the present study, the influence of the cognitive style called field dependence-independence on academic achievement of Brazilian university students was explored as well as the mediating effect of learning strategies on that influence. Learning strategies of 313 first-year university students (189 women and 124 men; M age = 20.86, SD = 3.86) from different fields, with upper, medium and lower scores on field dependence-independence were assessed on a self-report questionnaire and their overall academic marks in the first year were registered. Results of a regression analysis showed that cognitive style and learning strategies significantly contributed to academic achievement. A path analysis revealed that planning strategies mediated the influence of cognitive style on achievementNo presente estudo, a influência do estilo cognitivo dependência-independência de campo no rendimento acadêmico de estudantes universitários brasileiros foi explorada, bem como o efeito mediador das estratégias de aprendizagem nesta influência. As estratégias de aprendizagem de 313 estudantes universitários de primeiro curso (189 mulheres e 124 homens, idade M=20,86, DP= 3,86) a partir de diferentes domínios, com pontuações elevadas, intermediárias e baixas em dependência-independência de campo, foram avaliadas em um auto questionário e as suas médias globais de rendimento acadêmico no primeiro ano foram registradas. Resultados de uma análise de regressão mostraram que o estilo cognitivo e as estratégias de aprendizagem contribuem significativamente para o sucesso acadêmico. Uma path analysis revelou que as estratégias de planejamento mediam a influência do estilo cognitivo na sua realizaçãoS

In Vitro Gas Production and Dry Matter Degradability of Diets Consumed by Goats with or Without Copper and Zinc Supplementation

An in vitro gas production technique was used to evaluate the effects of copper and zinc supplementation on the amount and rate of gas production, dry matter degradability (IVDMD), utilization of metabolizable energy (ME), and ruminal fermentation patterns using rumen fluid from four Boermale goats as inoculum. The goats were fed twice daily at 07:00 and 19:00 h a total mixed ration containing 10.3 and 22.5 mg/kg DM of Cu and Zn, respectively. This diet was incubated in vitro for 96 h with four treatments being: control, Cu (21.7), Zn (5.6), and Cu–Zn (21.7 and 5.6) which was provided as a mineral premix. Data were analyzed as a completely randomized design. Rates of gas production (RGP) at 4 (RGP4h) and 6 h (RGP6h) and gas production (GP) at 24 (GP24h) and 48 h (GP48h) differed (p<0.01) among treatments. An addition of Cu increased the RGP4h, RGP6h, GP24h, and GP48h (p<0.0001). The Cu treatment had the highest IVDMD and control the lowest (p<0.05), and the Cu treatment was the highest values of ME and SCFA. The addition of Cu to the in vitro ruminal fermentation increased gas production and efficiency of energy use

Análisis comparativo del nivel de defectuosidad en los dispositivos de potencia SiC n-MOSFETs.

Actualmente, los transistores de efecto de campo fabricados en carburo de silicio son una tecnología emergente que está ingresando al mercado de los dispositivos de potencia, debido a los grandes beneficios que presenta esta familia de semiconductores con relación al silicio. Por su amplia brecha de banda energética, presenta varias peculiaridades de defectuosidad dentro de su estructura que afectan directamente a las características eléctricas de los dispositivos. El objetivo de este artículo es determinar y comparar el grado de defectuosidad al interno de la estructura MOS de los diferentes dispositivos bajo prueba. La técnica utilizada fue la caracterización de histéresis en corriente continua que es una medida de la dinámica de conmutación de las trampas en la interfaz SiC/SiO 2. Para lograr este propósito, experimentalmente se evaluó dos familias de dispositivos SiC MOSFETs de características eléctricas diferentes. Los dispositivos evaluados pertenecen al mismo fabricante. El grado de defectuosidad o trampas estimadas mostrado por cada dispositivo marca una tendencia de acuerdo con sus características eléctricas y su respectiva familia.Currently, the field-effect transistors (MOSFETs) manufactured in silicon carbide (SiC) are an emerging technology that is entering the market for power devices, due to the enormous ben efits of this family of semiconductors regarding silicon (Si). Due to its vast energy bandgap, SiC shows several structural defects affecting the electrical characteristics of the devices directly. This article aims to determine the level of defectiveness inside the MOS structure in different devices under test. The technique used was the hysteresis characterization in continuous current, which is a measurement of the switching dynamics of traps inside the SiC/SiO2 interface. In order to achieve this purpose, two families of SiC MOSFET devices with different electrical characteristics were experimentally evaluated. The assessed devices belong to the same manufacturer. The level of defectiveness or estimated traps for each device marks a trend according to their capability of electrical characteristics and family

Análisis comparativo del nivel de defectuosidad en los dispositivos de potencia SiC n-MOSFETs.

Actualmente, los transistores de efecto de campo fabricados en carburo de silicio son una tecnología emergente que está ingresando al mercado de los dispositivos de potencia, debido a los grandes beneficios que presenta esta familia de semiconductores con relación al silicio. Por su amplia brecha de banda energética, presenta varias peculiaridades de defectuosidad dentro de su estructura que afectan directamente a las características eléctricas de los dispositivos. El objetivo de este artículo es determinar y comparar el grado de defectuosidad al interno de la estructura MOS de los diferentes dispositivos bajo prueba. La técnica utilizada fue la caracterización de histéresis en corriente continua que es una medida de la dinámica de conmutación de las trampas en la interfaz SiC/SiO 2. Para lograr este propósito, experimentalmente se evaluó dos familias de dispositivos SiC MOSFETs de características eléctricas diferentes. Los dispositivos evaluados pertenecen al mismo fabricante. El grado de defectuosidad o trampas estimadas mostrado por cada dispositivo marca una tendencia de acuerdo con sus características eléctricas y su respectiva familia.Currently, the field-effect transistors (MOSFETs) manufactured in silicon carbide (SiC) are an emerging technology that is entering the market for power devices, due to the enormous ben efits of this family of semiconductors regarding silicon (Si). Due to its vast energy bandgap, SiC shows several structural defects affecting the electrical characteristics of the devices directly. This article aims to determine the level of defectiveness inside the MOS structure in different devices under test. The technique used was the hysteresis characterization in continuous current, which is a measurement of the switching dynamics of traps inside the SiC/SiO2 interface. In order to achieve this purpose, two families of SiC MOSFET devices with different electrical characteristics were experimentally evaluated. The assessed devices belong to the same manufacturer. The level of defectiveness or estimated traps for each device marks a trend according to their capability of electrical characteristics and family

Effect of different low-level intensity laser therapy (LLLT) irradiation protocols on the osseointegration of implants placed in grafted areas

Objective: To evaluate the effect of different protocols of low-level intensity laser therapy (LLLT) irradiation on the osseointegration of implants placed in grafted areas.&nbsp;Methodology: 84 rats were randomly allocated into six groups: DBB: defect filled with deproteinized bovine bone; HA/TCP: defect filled with biphasic ceramic of hydroxyapatite/β-tricalcium phosphate ; DBB-LI: defect filled with DBB and treated with LLLT after implant placement; HA/TCP-LI: defect filled with HA/TCP and treated with LLLT after implant placement; DBB-LIB: defect filled with DBB and treated with LLLT after graft procedure and implant placement; and HA/TCP-LIB: defect filled HA/TCP and treated with LLLT after graft procedure and implant placement. The bone defects were made in the tibia and they were grafted. After 60 days, the implants were placed. The rats were subsequently subjected to euthanasia 15 and 45 days after implant placement. The pattern of osseointegration and bone repair in the grafted area was evaluated by biomechanical, microtomographic, and histometric analyses. Furthermore, the expression of bone biomarker proteins was assessed.&nbsp;Results: The LLLT groups presented higher removal torque, mineralized tissue volume, and a greater degree of osseointegration, especially when LLLT was performed only after implant placement, and these findings were associated with higher expression of BMP2 and alkaline phosphatase.&nbsp;Conclusion: LLLT performed on implants placed in grafted areas enhances the osseointegration process