Estimación paramétrica del modelo de un mini-helicóptero robot usando un algoritmo genético y Matlab-Simulink

Basándose en el modelo matemático para un mini-helicóptero robot implementado en Matlab-Simulink y métodos heurísticos, específicamente un algoritmo genético (AG), se logro hacer la estimación de 16 parámetros en forma simultánea a nivel de simulación. Los resultados son altamente satisfactorios, teniendo en cuenta que fueron estimados con 12 salidas

Vibrational ladder-descending photostabilization of a weakly bound molecule: Quantum optimal control with a genetic algorithm

We propose an optical control scheme for driving a polar molecule from a high-lying vibrational level to a target low-lying one, within the same electronic state. The scheme utilizes an infrared chirped laser pulse with an analytical shape, whose parameters are optimized by means of a heuristic formulation of quantum optimal control based on a genetic algorithm. We illustrate this methodology computationally for a KRb Feshbach molecule in the lowest triplet electronic state

Influencia del tiempo de gelificación sobre las propiedades estructurales, vibracionales y eléctricas del compósito PEG0.2/V2O5

Se estudiaron las propiedades estructurales, vibracionales y eléctricas de películas V2O5·nH2O y PEG0.2/V2O5 en función del tiempo de gelificación. Las películas fueron sinterizadas por sol-gel mediante la ruta del pentóxido de vanadio sobre sustratos de vidrio previamente tratados. La caracterización se llevo a cabo mediante Difracción de Rayos-X, Espectroscopía Raman y el método de las cuatro puntas convencional de van der Pauw. Los resultados indican que el aumento en el tiempo de gelificación del sol precursor (V2O5.nH2O) incrementa la calidad cristalina, el grado de hidratación, y la concentración de iones V5+ en las películas. En el compósito híbrido (PEG0.2/V2O5) los iones VO2+ actúan como enlazantes entre las cadenas poliméricas haciéndolas más compactas, lo cual facilita la movilidad de los portadores de carga eléctrica entre los iones vanadios. Los resultados mostraron una transición de fase semiconductormetal alrededor de 34°C, una transición óptica del tipo indirecta (para V2O5·nH2O) y una transición vítrea alrededor de Tg=-69°C.Structural, vibrational and electrical properties of V2O5·nH2O and PEG0.2/V2O5 films as a function of gelation time were studied. The films were sintered by sol-gel using vanadium pentoxide route on glass substrates previously treated. Films were characterized by X-Ray Diffraction, Raman Spectroscopy and the four-point van der Pauw conventional method. The results indicated that when the gelation time of the precursor (V2O5·nH2O) is increased, the crystalline quality, the degree of hydration, and V5+ ion concentration are increased. In the hybrid composite (PEG0.2/V2O5), VO2+ ions act as bonding between the polymer chains, making them more compact to facilitate the mobility of electric charge carriers between vanadium ions. The results showed a semiconductor-metal transition about 34°C, an indirect optical transition (V2O5·nH2O) and a vitreous transition around Tg=-69°C.Fil: Londoño Calderon, Cesar Leandro. Universidad Nacional de Colombia; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jurado, J. F.. Universidad Nacional de Colombia; ColombiaFil: Vargas Hernández, C.. Universidad Nacional de Colombia; Colombi

Las Funciones Corporativas en el Grupo Empresarial Antioqueño durante la Última Década del Siglo XX

This article characterizes, from an administrative view, The Sindicato Antioqueño, de HQ of the same name modern business enterprise. The description is based on the main functions performed by this type of structure. The Sindicato Antioqueño's functions related with the portfolio definition, the external well as the internal administration, are described for the last decade of the XXth century, period defined by an open economy.En este artículo se ofrece una caracterización, desde el punto de vista administrativo, del Sindicato Antioqueño como centro corporativo a partir del conjunto de funciones que la literatura administrativa ha identificado como propias de estas estructuras que se reconocen en las empresas conformadas por los diferentes negocios. En este sentido, se presentan las actividades del Sindicato en la relación con la definición del portafolio, la gestión interna así como las funciones externas desempeñadas durante la última década del siglo XX, en el ambiente general del a apertura económica

Estrategia nacional para la conservación de las aves en Colombia

Sin resumenSin resume

Enfermedad carcinoide cardiaca multivalvular

ResumenHombre de 67 años de edad, enviado a valoración ecocardiográfica por cuadro clínico de 6meses de evolución con: disnea de esfuerzo, edemas de miembros inferiores y fatiga. Se encuentra doble lesión de la válvula tricúspide con: estenosis e insuficiencia severa, insuficiencia pulmonar severa; y compromiso valvular izquierdo con: insuficiencia mitral y aórtica severas, asociadas a engrosamiento y rigidez valvular. El paciente tenía como antecedente tumor neuroendocrino de íleon, metastásico a pulmón e hígado.En este caso se discuten los hallazgos ecocardiográficos característicos del síndrome carcinoide con compromiso multivalvular como hallazgo inusual de este raro síndrome.AbstractA 67 year-old man is sent to echocardiographic assessment for 6 month history of exertional: dyspnea, edema of the lower extremities, fatigue, double lesions in tricuspid valve with: severe stenosis and severe regurgitation, severe pulmonary valve regurgitation; and left side valvular disease with: severe aortic regurgitation and severe mitral regurgitation, all of them associated with valvular thickening, rigidity, in a patient with history of neuroendocrine tumor, with lung and liver metastases.This case discuss the echocardiographic findings suggestive of carcinoid multivalvular and left side valvular disease as unusual finding in this rare syndrome

Femtosecond pulses and dynamics of molecular photoexcitation: RbCs example

We investigate the dynamics of molecular photoexcitation by unchirped femtosecond laser pulses using RbCs as a model system. This study is motivated by a goal of optimizing a two-color scheme of transferring vibrationally-excited ultracold molecules to their absolute ground state. In this scheme the molecules are initially produced by photoassociation or magnetoassociation in bound vibrational levels close to the first dissociation threshold. We analyze here the first step of the two-color path as a function of pulse intensity from the low-field to the high-field regime. We use two different approaches, a global one, the 'Wavepacket' method, and a restricted one, the 'Level by Level' method where the number of vibrational levels is limited to a small subset. The comparison between the results of the two approaches allows one to gain qualitative insights into the complex dynamics of the high-field regime. In particular, we emphasize the non-trivial and important role of far-from-resonance levels which are adiabatically excited through 'vertical' transitions with a large Franck-Condon factor. We also point out spectacular excitation blockade due to the presence of a quasi-degenerate level in the lower electronic state. We conclude that selective transfer with femtosecond pulses is possible in the low-field regime only. Finally, we extend our single-pulse analysis and examine population transfer induced by coherent trains of low-intensity femtosecond pulses.Comment: 25 pages, 12 figure

Las Funciones Corporativas en el Grupo Empresarial Antioqueño durante la Última Década del Siglo XX

This article characterizes, from an administrative view, The Sindicato Antioqueño, de HQ of the same name modern business enterprise. The description is based on the main functions performed by this type of structure. The Sindicato Antioqueño's functions related with the portfolio definition, the external well as the internal administration, are described for the last decade of the XXth century, period defined by an open economy.En este artículo se ofrece una caracterización, desde el punto de vista administrativo, del Sindicato Antioqueño como centro corporativo a partir del conjunto de funciones que la literatura administrativa ha identificado como propias de estas estructuras que se reconocen en las empresas conformadas por los diferentes negocios. En este sentido, se presentan las actividades del Sindicato en la relación con la definición del portafolio, la gestión interna así como las funciones externas desempeñadas durante la última década del siglo XX, en el ambiente general del a apertura económica

Voltage Stability Analysis in Medium-Voltage Distribution Networks Using a Second-Order Cone Approximation

This paper addresses the voltage stability margin calculation in medium-voltage distribution networks in the context of exact mathematical modeling. This margin calculation is performed with a second-order cone (SOCP) reformulation of the classical nonlinear non-convex optimal power flow problems. The main idea around the SOCP approximation is to guarantee the global optimal solution via convex optimization, considering as the objective function the λ-coefficient associated with the maximum possible increment of the load consumption at all the nodes. Different simulation cases are considered in one test feeder, described as follows: (i) the distribution network without penetration of distributed generation; (ii) the distribution network with penetration of distributed generation; and (iii) the distribution grid with capacitive compensation. Numerical results in the test system demonstrated the effectiveness of the proposed SOCP approximation to determine the λ-coefficient. In addition, the proposed approximation is compared with nonlinear tools available in the literature. All the simulations are carried out in the MATLAB software with the CVX package and the Gurobi solver

Application of the sine-cosine algorithm to the optimal design of a closed coil helical spring

This paper proposes the application of the sinecosine algorithm (SCA) to the optimal design of a closed coil helical spring. The optimization problem addressed corresponds to the minimization of total spring volume subject to physical constraints that represents the closed coil helical spring such as maximum working load, shear stress, and minimum diameter requirements, among other. The resulting mathematical formulation is a complex nonlinear and non-convex optimization model that is typically addressed in literature with trial and error methods or heuristic algorithms. To solve this problem efficiently, the SCA is proposed in this research. This optimization algorithm belongs to the family of the metaheuristic optimization techniques, it works with controlled random processes guided by sine and cosine trigonometric functions, that allows exploring and exploiting the solution space in order to find the best solution to the optimization problem. By presenting as main advantage an easy implementation at any programming language using sequential quadratic programming; eliminating the need to uses specialized and costly software. Numerical results demonstrating that the proposes SCA allows reaching lower spring volume values in comparison with literature approaches, such as genetic algorithms, particle swarm optimization methods, among others. All the numerical simulations have been implemented in the MATLAB software