It is distribution of wealth harmful for economic growth?

It is the objective of this essay to analyse the relationship between income distribution and growth. In the first section, the central arguments of the more influential economic growth theories will be discussed. Next, the historical discussion involving the relationship between income distribution and economic growth will be outlined. Further to this I will examine the basic characteristics of models linking inequality and growth. Finally, the more recent literature regarding income distribution, social instability and economic growth will be addressed

Force Decomposition of 3D Unsteady Aerodynamics for 2 Symmetric Flapping Wings

Nowadays, the aerodynamic processes that are behind any flapping flight are not completely understood by the scientific community. Despite there are some numeri- cal methods which calculate the forces in 2D and 3D, these processes fail when they give an insight about the actual processes happening through a flapping system. In addition, these tools require a high computational time and the costs they sometimes present are very high. When flapping wings are studied, the method used is the force decomposition where the vortex structures acquire a decisive role for the development of these flights. For relevant studies, the 3D models seem to be the best option because the 2D ones do not generate results so similar to reality. For this reason, the optimum analysis for flapping wings is a 3D motion which is subjected to different kinematics and geometry conditions to see the evolution for each decomposed force. During this work, a code which computes the decomposed forces using Chang’s algorithm has been taken as a reference. This code could only compute the heaving motion for just one 3D wing. As a result of this project, it has been created a tool which is capable of computing the decomposed forces for 2 wings. In addition, though user inputs, the geometry and kinematic can be changed. The geometry by means of the Aspect Ratio and the kinematics through the radius of rotation. Once this is achieved, after the corresponding optimizations and validations, it has been studied the influence on results that a second wing could have on a first one. For this, it has been set a motion of Re=500 and reduced frequency k=1. The conclusion is that when the fluid is incompressible, there are no instabilities through the spanwise direction. As a consequence of this, the influence that the sec- ond wing has on the first one is negligible. Finally, different geometry and kinematic conditions have been presented with the same simulating conditions. Through this part, it has been analyzed the influence that the variation of these parameters has on the resultant forces. The conclusion for this analysis says that heaving motion produces a higher quantity of thrust and lift with respect the flapping one. This is due to the kinematics nature of each case. During the heaving process, the wing will move a higher quantity of air than the flapping one. Heaving motion produces constant vortex structures around the span, so it will produce a similar amount of forces over the spanwise. For the flapping case, the vortex structures decrease from the wing tip to the inboard tip, generating a smaller quantity of thrust and lift.A día de hoy, los procesos aerodinámicos que ocurren durante el vuelo de aleteo no son comprendidos en su totalidad. A pesar de que existen métodos numéricos que calculan las fuerzas en 2 y 3 dimensiones, estos procesos fallan a la hora de dar una visión de lo que realmente ocurre desde un punto de vista aerodinámico. Además estas herramientas requieren un tiempo computacional considerable y los costes suelen ser bastante elevados. En el estudio del vuelo de aleteo, el método empleado es la descomposición de fuerzas donde las estructuras vorticiales adquieren un papel decisivo en el desarrollo de estos vuelos. Para obtener resultados relevantes, los modelos tridimensionales son la mejor opción ya que aquellos en 2D no generan resultados tan similares a la realidad. Por ello, el análisis más óptimo que se puede hacer de vuelo en aleteo es un modelo en 3 dimensiones al cual se le someten diferentes tipos de movimientos y geometrías para comprobar la evolución de cada una de las fuerzas que intervienen en dicho movimiento. Este trabajo, se basa en un código que obtenía la descomposición de fuerzas utilizando el algoritmo de Chang [22]. Este código sólo admitía movimiento agitado para un único ala. El resultado de este estudio es una herramienta que permite calcular la descomposición de fuerzas para 2 alas simétricas a las que se puede someter diferentes condiciones de geometría y cinemática. La parte geométrica en el sentido del Aspect Ratio; y la parte cinemática cambiando el radio de rotación para obtener diferentes movimientos de aleteo. Una vez conseguido, tras las consiguientes optimizaciones y validaciones, se ha estudiado la influencia que una segunda ala puede tener en los resultados de las fuerzas calculadas en la primera. Para esto se ha establecido un Re=500 y una frecuencia reducida de k=1. La conclusión a la que se llega es que cuando el flujo es incompresible, para los campos vorticiales no hay inestabilidades a lo largo de la dirección de enveradura de las alas. Esto hace que la influencia de la segunda ala sobre la primera pueda considerarse despreciable. Finalmente, diferentes condiciones de geometría y cinemática se han establecido para estudiar la repercusión que estos dos parámetros pueden tener en la descomposición de fuerzas. La conclusión de este análisis dice que el movimiento agitado va a producir una mayor cantidad de empuje y sustentación respecto al vuelo en aleteo. Esto es debido a la naturaleza cinemática de cada movimiento: durante el proceso de agitado, el ala mueve mas masa de aire que el aleteo, por lo cual mayores fuerzas vorticiales se generarán en el cuerpo que más masa mueva.Ingeniería Aeroespacia

Learning sequences of rules using classifier systems with tags

IEEE International Conference on Systems, Man, and Cybernetics. Tokyo, 12-15 October 1999.The objective of this paper was to obtain an encoding structure that would allow the genetic evolution of rules in such a manner that the number of rules and relationship in a classifier system (CS) would be learnt in the evolution process. For this purpose, an area that allows the definition of rule groups has been entered into the condition and message part of the encoded rules. This area is called internal tag. This term was coined because the system has some similarities with natural processes that take place in certain animal species, where the existence of tags allows them to communicate and recognize each other. Such CS is called a tag classifier system (TCS). The TCS has been tested in the game of draughts and compared with the classical CS. The results show an improving of the CS performance

Applying classifier systems to learn the reactions in mobile robots

The navigation problem involves how to reach a goal avoiding obstacles in dynamic environments. This problem can be faced considering reactions and sequences of actions. Classifier systems (CSs) have proven their ability of continuous learning, however, they have some problems in reactive systems. A modified CS, namely a reactive classifier system (RCS), is proposed to overcome those problems. Two special mechanisms are included in the RCS: the non-existence of internal cycles inside the CS (no internal cycles) and the fusion of environmental message with the messages posted to the message list in the previous instant (generation list through fusion). These mechanisms allow the learning of both reactions and sequences of actions. This learning process involves two main tasks: first, discriminate between rules and, second, the discovery of new rules to obtain a successful operation in dynamic environments. DiVerent experiments have been carried out using a mini-robot Khepera to find a generalized solution. The results show the ability of the system for continuous learning and adaptation to new situations.Publicad

Knowledge acquisition including tags in a classifier system

Congress on Evolutionary Computation. Washington, DC, 6-9 July 1999.One of the major problems related to classifier systems is the loss of rules. This loss is caused by the genetic algorithm being applied on the entire population of rules jointly. Obviously, the genetic operators discriminate rules by the strength value, such that evolution favours the generation of the stronger rules. When the learning system works in an environment in which it is possible to generate a complete training set, the strength of the rules of the CS will reflect the relative relationship between rules satisfactorily and, therefore, the application of the genetic algorithm will produce the desired effects. However, when the learning process presents individual cases and allows the system to learn gradually from these cases, each learning interval with a set of individual cases can lead the strength to be distributed in favour of a given type of rules that would in turn be favoured by the genetic algorithm. Basically, the idea is to divide rules into groups such that they are forced to remain in the system. This contribution is a method of learning that allows similar knowledge to be grouped. A field in which knowledge-based systems researchers have done a lot of work is concept classification and the relationships that are established between these concepts in the stage of knowledge conceptualization for later formalization. This job of classifying and searching relationships is performed in the proposed classifier systems by means of a mechanism. Tags, that allows the classification and the relationships to be discovered without the need for expert knowledge

RTCS: a reactive with tags classifier system

In this work, a new Classifier System is proposed (CS). The system, a Reactive with Tags Classifier System (RTCS), is able to take into account environmental situations in intermediate decisions. CSs are special production systems, where conditions and actions are codified in order to learn new rules by means of Genetic Algorithms (GA). The RTCS has been designed to generate sequences of actions like the traditional classifier systems, but RTCS also has the capability of chaining rules among different time instants and reacting to new environmental situations, considering the last environmental situation to take a decision. In addition to the capability to react and generate sequences of actions, the design of a new rule codification allows the evolution of groups of specialized rules. This new codification is based on the inclusion of several bits, named tags, in conditions and actions, which evolve by means of GA. RTCS has been tested in robotic navigation. Results show the suitability of this approximation to the navigation problem and the coherence of tag values in rules classification.Publicad

Reactive with tags classifier system applied to real robot navigation

7th IEEE International Conference on Emerging Technologies and Factory Automation. Barcelona, 18-21 October 1999.A reactive with tags classifier system (RTCS) is a special classifier system. This system combines the execution capabilities of symbolic systems and the learning capabilities of genetic algorithms. A RTCS is able to learn symbolic rules that allow to generate sequence of actions, chaining rules among different time instants, and react to new environmental situations, considering the last environmental situation to take a decision. The capacity of RTCS to learn good rules has been prove in robotics navigation problem. Results show the suitability of this approximation to the navigation problem and the coherence of extracted rules

Numerical simulation of vortex-induced vibrations of a pair of cylinders

The 2-D numerical simulation of vortex-induced vibrations of twocloselyspaced parallel rigid circular cylinders, restrained by elastic springs and aligned in a normal direction with respect to the free stream flow, is presented in this work. Fluid-structure interaction is taken into account by a strong coupling based in equilibrium and compatibility conditions at the interfaces. A moving mesh, adjustable to the motion of the bodies, is included using an Arbitrary Lagrangean-Eulerian (ALE) description

Validación de la escala de Braden como instrumento predictor de desarrollo de las UPP (úlceras por presión) en el servicio de medicina hombres, Hospital Regional de Talca 2007-2008

59 P.El presente trabajo aborda el estudio de la calidad de atención y su relación con la aparición de Úlceras por Presión (UPP), en pacientes del género masculino, mayores de 60 años ingresados entre los años 2007 y 2008, al Servicio de Medicina Hombres del Hospital Regional de Talca, para lo cual se aplicaron procedimientos de validación de la escala de Braden, como un instrumento de predicción de la calidad de atención al adulto mayor.El estudio fue de tipo descriptivo prospectivo no experimental, la muestra total analizada fue de 207 pacientes, a los cuales se les aplicó la escala de Braden al ingreso y se evaluó el desarrollo de UPP durante 10 días consecutivos.Entre los hallazgos más relevantes, el riesgo de aparición de UPP al ingreso de los pacientes estuvo presente en el 46.49% (muestra 1) y el 40.42% (muestra 2), de éstos el 98.1% y el 96.8% de las muestras respectivas desarrollaron UPP. Además, se observó que, el riesgo que presenta el paciente al ingreso de su hospitalización, tiene una relación directa con el desarrollo de UPP, de tal forma que a mayor riesgo, mayor probabilidad de aparición de UPP, por lo tanto se concluye que es primordial la valoración inicial de riesgo para desarrollo de UPP al ingreso del paciente a través de la escala de Braden, la cual es válida y confiable para la población estudiada

Problem-Based Learning in Cell Biology: A Way to Explore Science

Con el fin de desarrollar el aprendizaje autónomo, el trabajo en equipo y mejorar la comunicación tanto oral como escrita de los alumnos de Biología Celular, hemos diseñado una serie de actividades en grupo fundamentadas en el aprendizaje basado en problemas. Cada grupo de estudiantes tenía que buscar una enfermedad humana cuya causa fuera consecuencia de un mal funcionamiento de las membranas celulares. El resultado debía ser presentado en una comunicación escrita y una comunicación oral como si se tratara de una comunicación científica a un Congreso. Así, hemos acercado la disciplina a una situación real a la que el alumnado se enfrentará como profesional. Aunque la valoración de los resultados de aprendizaje difiere entre el alumnado y el profesorado, analizamos las ventajas de este tipo de estrategia didáctica frente a la tradicional lección magistral.In order to develop strategies for autonomous learning and teamwork, and to improve written and oral communications skills for students of cell biology, we have designed several team activities founded on problem-based learning. Each team had to research a particular human disorder caused by dysfunctional proteins of cell membranes. The results were presented in a written and oral presentation in the same way as a scientific talk in a conference. Therefore, we have approached our discipline to a real situation that students will face as professionals. Although the assessment of learning outcomes differs between students and teachers, we analyze the benefits of this type of teaching strategy by comparing it to traditional methods based in lecture classes