Sintonización automática de velocidad y posición para servomotores utilizando control difuso

T E SI S QUE PARA OBTENER EL GRADO DE MAESTRO EN CIENCIAS DE LA COMPUTACIÓNEl presente trabajo de investigación, consiste en el desarrollo de un controlador para servomotor, utilizando lógica difusa para controlar velocidad y posición. Los servomotores tienen una gran cantidad de aplicaciones de tipo industrial, principalmente en la fabricación de robots industriales, máquinas de control numérico y procesos que requieren control de movimiento preciso. La incorporación de los controladores de lógica difusa para procesos complejos permite al sistema, trabajar más cercano a la forma en que el cerebro humano funciona. La implementación de este sistema en lugar de uno lineal (PID) proporciona robustez y fiabilidad. Como ya se ha mencionado anteriormente el control de servomotores se lleva a cabo mediante algoritmos de control de tipo lineal, dentro de los que pueden resaltarse, el Proporcional (P), Integral (I), y Derivativo (D), todos estos aplicados de manera independiente según sean los requerimientos del proceso a controlar, o bien; pueden funcionar de manera combinada como el PI, el PD, o el PID, sin embargo ante cambios no lineales, su funcionamiento se ve afectado, pues dejan de trabajar eficazmente. Tomando como base de conocimiento lo anterior, se diseñó un controlador lógico difuso (fuzzy), de tipo Mamdani, que funciona con dos variables lingüísticas de entrada (velocidad y posición), un motor de inferencia difuso compuesto por un conjunto de reglas de tipo IF, THEN, ELSE, conocido como etapa de fuzzificación. A la salida del controlador se tiene una señal defuzzificada misma que se bifurca para retroalimentar al sistema, cerrando así, su lazo de control. La construcción del controlador se realizó en Matlab, utilizando para ello su módulo de edición de lógica difusa (Fuzzy Logic Designer), en un ambiente de programación gráfico e intuitivo. Por otra parte la implementación, se realizó en Labview, debido a su facilidad y rapidez para construir la interfaz gráfica y los modelos lineales que se usaron como referencia. Por lo anterior, el diseño de controladores PID basados en lógica difusa, es motivado por la habilidad de estos de capturar estrategias cualitativas de control y ofrecer un comportamiento altamente flexible

The Quest for a Practical Sophomore-Level Software Engineering Course

This paper describes our efforts starting since 2014 when we began developing a practical introductory sophomore-level software engineering course. The aim is to guide students into the fundamental theory and practice of building reliable software, with an emphasis on agile and object-oriented practices. Course topics revolve around three main themes: 1) managing complexity (how to model and scale software), 2) achieving quality (how to minimize defects) and 3) supporting usability (how to deliver user functionality). Students are exposed to theoretical and practical aspects of software production, such as software life-cycle models, strong-typing, testing, documentation, graphical user interfaces, UML, design patterns, version control systems and software deployment. The course is in constant evolution: near-future plans include adding build automation tools and DevOps concepts. We made the early decision to use reference materials available to our students at no cost; therefore, all reference materials are accessed online through resources afforded by our library

Understanding The Factors Affecing Expatriate Teacher Retention In a Cross-Cultural Setting: A Case Study of an American International Sschool In Panama

The purpose of this study was to investigate the factors that affect expatriate teacher retention. The research aimed to identify the factors that contribute to expatriate teacher adaptation and retention in cross-cultural settings. As the demand for expatriate teachers has increased with the growth of international schools, retaining them has become a persistent challenge. The scarcity of literature on expatriate teacher retention, combined with high turnover rates and an expanding demand for such teachers, highlights the need for further research in this area. Therefore, this study aimed to fill this gap by exploring the factors that impact expatriate teacher retention and ultimately provide valuable insights to improve support for expatriate teachers in cross-cultural settings. The study investigated the factors that influence expatriate teachers\u27 decisions to renew their contracts at the end of their term. The research findings revealed that expatriate teachers with higher levels of intercultural competence were more likely to adapt to new environments and foster positive relationships with students, colleagues, and the local community. These positive experiences increased their motivation to stay at their current school and renew their contracts. Moreover, the study identified the importance of organizational conditions and leadership factors in shaping expatriate teachers\u27 retention decisions. Therefore, the research emphasizes the significance of intercultural competence, organizational support, and leadership in promoting expatriate teacher retention in cross-cultural settings. The researcher utilized both quantitative and qualitative assessment methods to comprehensively investigate the phenomenon in the context of teacher retention in cross-cultural settings. In addition to this, the researcher conducted in-depth interviews with the participants to gain a deeper understanding of their personal experiences and perceptions. The findings of this study indicate that intercultural competence plays a pivotal role in retaining teachers in cross-cultural settings. Furthermore, the study highlights the significance of organizational conditions and leadership factors in shaping expatriates\u27 decisions to remain at a school. To enhance support for expatriate teachers in adapting to cross-cultural environments and improving retention rates, further research in these areas is crucial. However, it is essential to exercise caution when extrapolating the results of this study to other expatriates in cross-cultural settings, as wider generalizations necessitate additional research

Speaking Private Authority: The Construction of Sustainability in Forests and Fisheries

The aim of this dissertation is to expand upon current understandings of the emergent global phenomenon that is private authority. Private authority is a process wherein private actors create, implement, and enforce rules aimed at managing global problems. As private authority is becoming increasingly important in the conduct of global governance, broadening our understanding of it will serve the field of International Relations. In this dissertation I argue that private actors are not simply outgrowths of structures or certain material conditions, rather they are purposive actors strategically pursuing an agenda. As such, explaining private authority requires an examination of the constitutive elements that underlie this social phenomenon––to which I apply an innovative conceptual and analytical framework that combines social network theory with discourse analysis. I applied these tools to two cases taken from the environmental sector––forests and fisheries. I found that as a result of the development of a greater networked character to environmental politics, the actors that were best able to generate and wield private authority were those that were able to construct discursive nodal points around which other competing actors could converge––at the level of identity. The construction of nodal points placed these private actors in privileged positions in-between competing networks––making them network connectors. In this position they are able to facilitate the flow of power across networks and convert such into private authority, at a rate greater than that of their competitors. As related to the cases, I found that in forests and fisheries sectors it was the Forest Stewardship Council and Marine Stewardship Council that emerged as the most prominent and expansive private authorities. They did so as a result of their ability to construct a nodal point around their tailored definition of what sustainable development meant, and looked like in practice. This placed them in-between two powerful networks (the environmental NGO network and the industrial network), facilitating the flow of power between them, and leveraging such to expand their programs beyond that of competing programs. Thus, social position plays a crucial role in determining the success of private authority programs

Modelling dependencies in airport passenger : claim data using copulas

Mestrado Bolonha em Actuarial ScienceEvery year, thousands of passengers flying through U.S. airports file claims to the Transportation Security Administration (TSA). The objective of this dissertation is to use copulas to model dependencies in counts and severities for TSA claims, during the years 2007-2015. Initially, monthly claim counts and amounts are aggregated from daily records, according to their type and site. These monthly series are detrended and fit into different probability distributions using Maximum Likelihood Estimation (MLE), to obtain the corresponding parameters. Once the marginal distributions are obtained, it is possible to fit them into different bivariate copulas. These bivariate copulas are used to determine different tail dependence measures and to highlight non-linear dependencies between the variables. The final procedure involves fitting multivariate copulas and performing simulations. These simulations contrast risk measures like monthly Value at Risk (VaR) and Tail Value at Risk (TVaR) estimates for the different copulas used, along with the independence case and historical values. The results show modelling claims with copulas can yield higher risk measures than the historical values, for random variables with heavy-tailed distributions. The choice of the copula used is also important in this sense, as different copulas generate different simulated risk measures. All of the data processing and modelling is performed using different open source Python libraries.info:eu-repo/semantics/publishedVersio

Numerical simulation of flow over a flapping airfoil

This project presents the study of the aerodynamic forces acting on a plunging and pitching airfoil by performing two-dimensional Direct Numerical Simulation to solve the Navier-Stokes equations for incompressible flow around an airfoil with an Immersed Boundary Method. This analysis is performed on NACA-0012 symmetric airfoils at reduced frequency of k = 0.2π and plunging amplitude of h/c = 1. Different flapping configurations are considered by combining different mean pitch angles of θm = 0◦ and 10◦, pitching amplitude of θ0 = 0◦, 10◦, 20◦ and 30◦ and Reynolds number of Re = 3000, 1000 and 500 at fixed phase shift φ = 90◦. The different simulated cases display diverse flow wake structures. The role of leading edge vortex and trailing edge vortex were found to be one key in the observed performance variation. For the analysed cases, it was noticed that the resulting wake structures are influenced by Re for flapping configuration with non-zero pitching amplitude, but they are independent of Re for zero pitching amplitude motions. Also, it was observed that increasing θ0 results in lower effective angle of attack producing disappearance of vortex structures. Finally, this work evaluates the performance of a simplified model, developed in a parallel project [Moriche et al., 2016], to predict the aerodynamic forces acting on a flapping airfoil. It was noted that this model has an enormous potential to predict lift and thrust generation, even though it has a great simplicity.Ingeniería Aeroespacia

¿Qué es Organic Eprints?

La Sociedad Científica Latinoamericana de Agroecología – SOCLA, e IFOAM América Latina (Federación Internacional de Movimientos de Agricultura Orgánica – Grupo Regional de América Latina), en ocasión de realizarse el IV Congreso Latinoamericano de Agroecología, pone a disposición de la comunidad científica, miembros y colaboradores del movimiento agroecológico en la región; el servicio que brinda Organic Eprints con la finalidad de difundir y poner disponible en la internet, los trabajos presentados y aprobados por la comisión de evaluación de artículos del Congreso. Los invitamos a utilizar este práctico y útil repositorio de documentos científicos y de investigación, así como trabajos basados en las experiencias agroecológicas

PUMI: An explicit ED unstructural finite element solver for the Euler equations

The PUMI flow solver has been developed at CIMNE in to address the need for fast solutions of the flow field around complex geometries. Nowadays calculations involving a number of cells on the order of ten million are performed routinely. PUMI was created to deal with this kind of large-scale problem using modest hardware, therefore special emphasis was placed on the computational efficiency of the code. Design guidelines where minimum memory requirement, very fast single-threaded performance as well as satisfactory parallel scaling up to a moderate number of threads (as found on current desktop hardware using a small number of multi-core CPUs. In order to speedup the mesh generation activities an unstructured finite element formulation was selected. This papers describes the theoretical basis of the algorithms as well as detail of the implementation that increase the robustness and efficiency of the code

Adapting In-Game Agent Behavior by Observation of Players Using Learning Behavior Trees

In this paper we describe Learning Behavior Trees, an extension of the popular game AI scripting technique. Behavior Trees provide an effective way for expert designers to describe complex, in-game agent behaviors. Scripted AI captures human intuition about the structure of behavioral decisions, but suffers from brittleness and lack of the natural variation seen in human players. Learning Behavior Trees are designed by a human designer, but then are trained by observation of players performing the same role, to introduce human-like variation to the decision structure. We show that, using this model, a single hand-designed Behavior Tree can cover a wide variety of player behavior variations in a simplified Massively Multiplayer Online Role-Playing Game