11 resultados para launching sideline
em Universidad Politécnica de Madrid
Resumo:
Conditions leading to a maximum range for a small, round projectile, fired by hand, are discussed taking into account air drag and the dependence of the initial speed on the mass launched. Both the optimal angle of release for given projectile and initial speed, and the optimal radius for given density (i.e., among a bed of pebbles) are determined; an increase on the height of release is found to always decrease the angle and increase the radius. The influence of the projectile mass on the optimal manner of launching is considered. The validity of the approximations used in the analysis is discussed. Results from very simple measurements show good agreement with theory.
Resumo:
The Vicario Viaduct is located in the A-44 motorway, in the South-East part of Spain. It crosses a natural gorge, near the town of zbor in the province of Granada. A single continuous steel concrete composite deck, 24 m wide and 175 m long, divided in two 87,5 m spans, has been built. The cross section is a single structural steel box, 8,00 m wide and 4,52 m deep. The total width of 24 m is reached adding a strut and tie system each 4,375 m on both sides of the box. The steel parts of the deck were entirely constructed in the workshop and then they were erected on site just behind one of the abutments. Finally a 27.5 m long steel nose was connected to launch the deck. The main problems have been the curved shape of the deck (1420 m radius in plan) producing a non symmetric transverse distribution of reactions on each support and the cantilever reaching 87,5 m long, producing a maximum deflection of 1500 mm
Resumo:
In this work, we present a novel interferometer based on liquid crystal and photonic crystal fiber technology. The objective of this project is the development of a tunable (switchable) modal (Mach-Zehnder) interferometer for optical communications or sensing. This interferometer has been manufactured splicing a short portion (between 15 and 30 mm) of photonic crystal fiber with two single mode fiber pigtails. The study shows a high sensitivity of the interferometer to the polarization of the launching light.
Resumo:
Este trabajo trata sobre el desarrollo de una Start Up de base tecnolgica desde la universidad. La empresa creada comercializar un servicio software para comedores y restaurantes. La actualidad est marcada por la economa, y en estos momentos nos encontramos con una tasa de paro general del 26,7%, en ingenieras (la UPM) es del 31,2%. El sector de las TIC se salva por el momento (en informtica la tasa de paro es del 4,8%), aunque el trabajo en muchos casos es precario y las oportunidades para desarrollar una carrera plena pasan por ir a trabajar a otros pases que tienen una situacin laboral ms favorable. Tambin tenemos la alternativa de trabajar como autnomos, creando empresas y, con suerte, generando un nuevo empleo. En Espaa existen iniciativas de ayuda pblica y privada que ayudan a convertir ideas en empresas, incubadoras, aceleradoras, ayudas pblicas, ferias tecnolgicas, concursos que ayudan a ganar visibilidad, etc. Este proyecto naci gracias a una de estas iniciativas, ms en concreto a ACTUA UPM, iniciativa de la propia UPM a travs de la unidad Creacin de Empresas. Para crear una empresa no basta un buen servicio o un buen producto, es necesario poder venderlo. Por lo que el primer esfuerzo debe realizarse en comprobar que nuestro producto tiene caractersticas que pueden cubrir una necesidad que ya existe y que las condiciones indican que puede ser rentable. Esta es la primera fase, la creacin de un plan de negocio y de marketing. A continuacin basndonos en la manera en la que decidimos que venderemos nuestro producto, orientaremos el desarrollo para hacer hincapi en los puntos fuertes que pueden hacer nuestro producto diferente y deseado. La fase de desarrollo es mi caso es sobre todo una fase de aprendizaje, en la que aprender a fondo tecnologas web y mvil, y aplicar los conocimientos adquiridos en mis estudios. A continuacin, se ofrece mi experiencia desarrollando la empresa desde la idea hasta conseguir un producto preparado para ponerlo a prueba. ---ABSTRACT---This paper is about the development of a technological based Start Up from the college. The company will market a software service oriented to canteens and restaurants. Economy is what rules the world, and today we are facing a very strong crisis with a 26.7% of unemployment rate in Spain. However, the IT sector is less affected than others by this crisis (Informatics Engineers has a 4.8% unemployment rate). But in many cases jobs are precarious and young people have to leave our country for pursuing a decent career. Also we have the option of self-employment, launching a company, and with some luck, creating a new job. We have some tools for launching new technological base business. Many people hopes to create the new Facebook, and many investors are interested in being on the boat if that happens. Also at UPM we have ACTUA UPM, which promotes ideas into companies. My idea was born in it and managed to the final round. For launching a new company you need to do a business plan that studies the possible pitfalls of your idea and directs your development efforts to the way your product is going to be sold. So the first phase of this paper will talk about the development of the business plan. After it, the development phase is in essence a phase of learning in which I faced most problems in my own, giving the best solutions I could from my own experience and intuition. Then, we present the experience of developing a Start Up from the idea to the market testing.
Resumo:
Durante los ltimos aos la utilizacin de los LEDs (Light Emitting Diodes) ha aumentado de forma muy importante siendo hoy en da una alternativa real a los sistemas de iluminacin tradicionales. La iluminacin basada en LEDs se est utilizando ampliamente en automocin, arquitectura, aplicaciones domsticas y sealizacin debido a su alta fiabilidad, pequeo tamao y bajo consumo. La evaluacin de la fiabilidad de los LEDs es un tema clave previo a la comercializacin o a la puesta en marcha del LED en una nueva aplicacin. La evaluacin de la fiabilidad de dispositivos requiere ensayos acelerados para obtener resultados de fiabilidad en un periodo de tiempo aceptable, del orden de pocas semanas. En ste proyecto se estudia la fiabilidad de dos tipos diferentes de LEDs ultravioleta, que pueden sustituir a las lmparas UV convencionales, para diferentes condiciones de trabajo y diferentes condiciones ambientales. Se hace un seguimiento de la evolucin de los LEDs UV durante cientos horas de ensayo acelerado para obtener resultados y conclusiones acerca de la degradacin que sufren. La memoria del proyecto fin de carrera se ha estructurado en siete captulos. Tres de ellos son tericos, otros tres prcticos y finalmente uno sobre el presupuesto. El primero explica la introduccin y la evolucin del diodo LED, el segundo introduce la fiabilidad explicando los modelos ms utilizados para analizar los ensayos y el tercero es un breve tema acerca de los ensayos acelerados. Los otros tres captulos son orientados a los experimentos realizados en este Proyecto Fin de Carrera. Uno trata sobre la descripcin del ensayo acelerado realizado, otro analiza los resultados obtenidos, el siguiente analiza las conclusiones y el ltimo el presupuesto. ABSTRACT. For the last years, the use of LEDs (Light Emitting Diodes) has increased significantly, being nowadays a real alternative to traditional lighting systems. Lighting based on LEDs is being extensively used in automotive, domestic applications and signaling due to its high reliability small size and low power consumption. The evaluation of LEDs reliability is a key issue before marketing or launching a new application. The reliability evaluation of devices requires accelerated tests to obtain reliability results in an acceptable period of time, for the order of few weeks. In this project the reliability of two different types of UV LEDs, which can replace conventional UV lamps for different conditions and different environmental conditions is studied. The evolution of LEDs UV is tracked during hundred hours of accelerated test to obtain the results and conclusions about the degradation suffered. The memory of the final project has been structured into seven chapters. Three of them are theorical another three are experimental and the last one about estimates. The first explains the introduction and development of LED, the second introduces the reliability explaining the most used models to analyze the tests and the third is a brief topic about the accelerated tests. The other three chapters are oriented to the experiments done in this PFC. One explains the description of the accelerated test we have done, another analyzes the results obtained, the following one exposes the conclusions and the last one the estimates.
Resumo:
El objetivo de este documento es desarrollar un plan de negocio, para analizar la viabilidad de la puesta en marcha de una nueva empresa, una escuela de cocina infantil. Inicialmente la empresa se plantea con la opcin de venta de dos productos, uno que seran las propias clases de cocina, con diversas temticas y un segundo producto, que aprovechando las instalaciones consistir en la opcin de celebrar cumpleaos o fiestas infantiles, donde los nios cocinaran su propia merienda. La escuela se abrira en el municipio de Coslada, en la comunidad de Madrid, por lo que todos los reglamentos o requerimientos legales e impuestos se analizaran dentro del prisma de dicho municipio y comunidad autnoma. El Plan de negocio analizara los siguientes aspectos: - Estrategia: creacin del plan estratgico de la empresa: Anlisis y seleccin de las estrategias (misin, visin, etc, de la empresa), estudio de competencias, etc. - Marketing: Definicin de productos, canales de comunicacin con los posibles clientes y desarrollo del pricing de los productos. - Financiero: Anlisis del impacto financiero de la apertura y funcionamiento del proyecto.---ABSTRACT---The aim of this document is to develop a business plan to analyze the feasibility of launching a new business, a school for children kitchen. Initially the company raises two products, own cooking classes, with different themes and a second product through which the facilities for children's birthday celebration where children can take advantage cook their own snacks. The school would open in the town of Coslada, in Madrid, so that all regulations and legal requirements and fees will be analyzed within the prism of that community. The Business Plan will analyze aspects of: - Strategy: creation of the strategic plan of the company: Analysis and selection of strategies (mission, vision, etc, of the company), study skills, etc. - Marketing: Definition of products, channels of communication with potential customers and development products pricing. - Financial Analysis of the financial impact of the opening and operation of the project.
Resumo:
Las futuras misiones para misiles aire-aire operando dentro de la atmsfera requieren la interceptacin de blancos a mayores velocidades y ms maniobrables, incluyendo los esperados vehculos areos de combate no tripulados. La intercepcin tiene que lograrse desde cualquier ngulo de lanzamiento. Una de las principales discusiones en la tecnologa de misiles en la actualidad es cmo satisfacer estos nuevos requisitos incrementando la capacidad de maniobra del misil y en paralelo, a travs de mejoras en los mtodos de guiado y control modernos. Esta Tesis aborda estos dos objetivos simultneamente, al proponer un diseo integrando el guiado y el control de vuelo (autopiloto) y aplicarlo a misiles con control aerodinmico simultneo en canard y cola. Un primer avance de los resultados obtenidos ha sido publicado recientemente en el Journal of Aerospace Engineering, en Abril de 2015, [Ibarrondo y Sanz-Aranguez, 2015]. El valor del diseo integrado obtenido es que permite al misil cumplir con los requisitos operacionales mencionados empleando nicamente control aerodinmico. El diseo propuesto se compara favorablemente con esquemas ms tradicionales, consiguiendo menores distancias de paso al blanco y necesitando de menores esfuerzos de control incluso en presencia de ruidos. En esta Tesis se demostrar cmo la introduccin del doble mando, donde tanto el canard como las aletas de cola son mviles, puede mejorar las actuaciones de un misil existente. Comparado con un misil con control en cola, el doble control requiere slo introducir dos servos adicionales para accionar los canards tambin en guiada y cabeceo. La seccin de cola ser responsable de controlar el misil en balanceo mediante deflexiones diferenciales de los controles. En el caso del doble mando, la complicacin aadida es que los vrtices desprendidos de los canards se propagan corriente abajo y pueden incidir sobre las superficies de cola, alterando sus caractersticas de control. Como un primer aporte, se ha desarrollado un modelo analtico completo para la aerodinmica no lineal de un misil con doble control, incluyendo la caracterizacin de este efecto de acoplamiento aerodinmico. Hay dos modos de funcionamiento en picado y guiada para un misil de doble mando: desviacin y opuesto. En modo desviacin, los controles actan en la misma direccin, generando un cambio inmediato en la sustentacin y produciendo un movimiento de translacin en el misil. La respuesta es rpida, pero en el modo desviacin los misiles con doble control pueden tener dificultades para alcanzar grandes ngulos de ataque y altas aceleraciones laterales. Cuando los controles actan en direcciones opuestas, el misil rota y el ngulo de ataque del fuselaje se incrementa para generar mayores aceleraciones en estado estacionario, aunque el tiempo de respuesta es mayor. Con el modelo aerodinmico completo, es posible obtener una parametrizacin dependiente de los estados de la dinmica de corto periodo del misil. Debido al efecto de acoplamiento entre los controles, la respuesta en bucle abierto no depende linealmente de los controles. El autopiloto se optimiza para obtener la maniobra requerida por la ley de guiado sin exceder ninguno de los lmites aerodinmicos o mecnicos del misil. Una segunda contribucin de la tesis es el desarrollo de un autopiloto con mltiples entradas de control y que integra la aerodinmica no lineal, controlando los tres canales de picado, guiada y cabeceo de forma simultnea. Las ganancias del autopiloto dependen de los estados del misil y se calculan a cada paso de integracin mediante la resolucin de una ecuacin de Riccati de orden 21x21. Las ganancias obtenidas son sub-ptimas, debido a que una solucin completa de la ecuacin de Hamilton-Jacobi-Bellman no puede obtenerse de manera prctica, y se asumen ciertas simplificaciones. Se incorpora asimismo un mecanismo que permite acelerar la respuesta en caso necesario. Como parte del autopiloto, se define una estrategia para repartir el esfuerzo de control entre el canard y la cola. Esto se consigue mediante un controlador aumentado situado antes del bucle de optimizacin, que minimiza el esfuerzo total de control para maniobrar. Esta ley de alimentacin directa mantiene al misil cerca de sus condiciones de equilibrio, garantizando una respuesta transitoria adecuada. El controlador no lineal elimina la respuesta de fase no-mnima caracterstica de la cola. En esta Tesis se consideran dos diseos para el guiado y control, el control en Doble-Lazo y el control Integrado. En la aproximacin de Doble-Lazo, el autopiloto se sita dentro de un bucle interior y se disea independientemente del guiado, que conforma el bucle ms exterior del control. Esta estructura asume que existe separacin espectral entre los dos, esto es, que los tiempos de respuesta del autopiloto son mucho mayores que los tiempos caractersticos del guiado. En el estudio se combina el autopiloto desarrollado con una ley de guiado ptimo. Los resultados obtenidos demuestran que se consiguen aumentos muy importantes en las actuaciones frente a misiles con control canard o control en cola, y que la interceptacin, cuando se lanza cerca del curso de colisin, se consigue desde cualquier ngulo alrededor del blanco. Para el misil de doble mando, la estrategia ptima resulta en utilizar el modo de control opuesto en la aproximacin al blanco y utilizar el modo de desviacin justo antes del impacto. Sin embargo la lgica de doble bucle no consigue el impacto cuando hay desviaciones importantes con respecto al curso de colisin. Una de las razones es que parte de la demanda de guiado se pierde, ya que el misil solo es capaz de modificar su aceleracin lateral, y no tiene control sobre su aceleracin axial, a no ser que incorpore un motor de empuje regulable. La hiptesis de separacin mencionada, y que constituye la base del Doble-Bucle, puede no ser aplicable cuando la dinmica del misil es muy alta en las proximidades del blanco. Si se combinan el guiado y el autopiloto en un nico bucle, la informacin de los estados del misil est disponible para el clculo de la ley de guiado, y puede calcularse la estrategia optima de guiado considerando las capacidades y la actitud del misil. Una tercera contribucin de la Tesis es la resolucin de este segundo diseo, la integracin no lineal del guiado y del autopiloto (IGA) para el misil de doble control. Aproximaciones anteriores en la literatura han planteado este sistema en ejes cuerpo, resultando en un sistema muy inestable debido al bajo amortiguamiento del misil en cabeceo y guiada. Las simplificaciones que se tomaron tambin causan que el misil se deslice alrededor del blanco y no consiga la intercepcin. En nuestra aproximacin el problema se plantea en ejes inerciales y se recurre a la dinmica de los cuaterniones, eliminado estos inconvenientes. No se limita a la dinmica de corto periodo del misil, porque se construye incluyendo de modo explcito la velocidad dentro del bucle de optimizacin. La formulacin resultante en el IGA es independiente de la maniobra del blanco, que sin embargo se ha de incluir en el clculo del modelo en Doble-bucle. Un tpico inconveniente de los sistemas integrados con controlador proporcional, es el problema de las escalas. Los errores de guiado dominan sobre los errores de posicin del misil y saturan el controlador, provocando la prdida del misil. Este problema se ha tratado aqu con un controlador aumentado previo al bucle de optimizacin, que define un estado de equilibrio local para el sistema integrado, que pasa a actuar como un regulador. Los criterios de actuaciones para el IGA son los mismos que para el sistema de Doble-Bucle. Sin embargo el problema matemtico resultante es muy complejo. El problema ptimo para tiempo finito resulta en una ecuacin diferencial de Riccati con condiciones terminales, que no puede resolverse. Mediante un cambio de variable y la introduccin de una matriz de transicin, este problema se transforma en una ecuacin diferencial de Lyapunov que puede resolverse mediante mtodos numricos. La solucin resultante solo es aplicable en un entorno cercano del blanco. Cuando la distancia entre misil y blanco es mayor, se desarrolla una solucin aproximada basada en la solucin de una ecuacin algebraica de Riccati para cada paso de integracin. Los resultados que se han obtenido demuestran, a travs de anlisis numricos en distintos escenarios, que la solucin integrada es mejor que el sistema de Doble-Bucle. Las trayectorias resultantes son muy distintas. El IGA preserva el guiado del misil y consigue maximizar el uso de la propulsin, consiguiendo la interceptacin del blanco en menores tiempos de vuelo. El sistema es capaz de lograr el impacto donde el Doble-Bucle falla, y adems requiere un orden menos de magnitud en la cantidad de clculos necesarios. El efecto de los ruidos radar, datos discretos y errores del radomo se investigan. El IGA es ms robusto, resultando menos afectado por perturbaciones que el Doble- Bucle, especialmente porque el ncleo de optimizacin en el IGA es independiente de la maniobra del blanco. La estimacin de la maniobra del blanco es siempre imprecisa y contaminada por ruido, y degrada la precisin de la solucin de Doble-Bucle. Finalmente, como una cuarta contribucin, se demuestra que el misil con guiado IGA es capaz de realizar una maniobra de defensa contra un blanco que ataque por su cola, slo con control aerodinmico. Las trayectorias estudiadas consideran una fase pre-programada de alta velocidad de giro, manteniendo siempre el misil dentro de su envuelta de vuelo. Este procedimiento no necesita recurrir a soluciones tcnicamente ms complejas como el control vectorial del empuje o control por chorro para ejecutar esta maniobra. En todas las demostraciones matemticas se utiliza el producto de Kronecker como una herramienta practica para manejar las parametrizaciones dependientes de variables, que resultan en matrices de grandes dimensiones. ABSTRACT Future missions for air to air endo-atmospheric missiles require the interception of targets with higher speeds and more maneuverable, including forthcoming unmanned supersonic combat vehicles. The interception will need to be achieved from any angle and off-boresight launch conditions. One of the most significant discussions in missile technology today is how to satisfy these new operational requirements by increasing missile maneuvering capabilities and in parallel, through the development of more advanced guidance and control methods. This Thesis addresses these two objectives by proposing a novel optimal integrated guidance and autopilot design scheme, applicable to more maneuverable missiles with forward and rearward aerodynamic controls. A first insight of these results have been recently published in the Journal of Aerospace Engineering in April 2015, [Ibarrondo and Sanz-Arnguez, 2015]. The value of this integrated solution is that it allows the missile to comply with the aforementioned requirements only by applying aerodynamic control. The proposed design is compared against more traditional guidance and control approaches with positive results, achieving reduced control efforts and lower miss distances with the integrated logic even in the presence of noises. In this Thesis it will be demonstrated how the dual control missile, where canard and tail fins are both movable, can enhance the capabilities of an existing missile airframe. Compared to a tail missile, dual control only requires two additional servos to actuate the canards in pitch and yaw. The tail section will be responsible to maintain the missile stabilized in roll, like in a classic tail missile. The additional complexity is that the vortices shed from the canard propagate downstream where they interact with the tail surfaces, altering the tail expected control characteristics. These aerodynamic phenomena must be properly described, as a preliminary step, with high enough precision for advanced guidance and control studies. As a first contribution we have developed a full analytical model of the nonlinear aerodynamics of a missile with dual control, including the characterization of this cross-control coupling effect. This development has been produced from a theoretical model validated with reliable practical data obtained from wind tunnel experiments available in the scientific literature, complement with computer fluid dynamics and semi-experimental methods. There are two modes of operating a missile with forward and rear controls, divert and opposite modes. In divert mode, controls are deflected in the same direction, generating an increment in direct lift and missile translation. Response is fast, but in this mode, dual control missiles may have difficulties in achieving large angles of attack and high level of lateral accelerations. When controls are deflected in opposite directions (opposite mode) the missile airframe rotates and the body angle of attack is increased to generate greater accelerations in steady-state, although the response time is larger. With the aero-model, a state dependent parametrization of the dual control missile short term dynamics can be obtained. Due to the cross-coupling effect, the open loop dynamics for the dual control missile is not linearly dependent of the fin positions. The short term missile dynamics are blended with the servo system to obtain an extended autopilot model, where the response is linear with the control fins turning rates, that will be the control variables. The flight control loop is optimized to achieve the maneuver required by the guidance law without exceeding any of the missile aerodynamic or mechanical limitations. The specific aero-limitations and relevant performance indicators for the dual control are set as part of the analysis. A second contribution of this Thesis is the development of a step-tracking multi-input autopilot that integrates non-linear aerodynamics. The designed dual control missile autopilot is a full three dimensional autopilot, where roll, pitch and yaw are integrated, calculating command inputs simultaneously. The autopilot control gains are state dependent, and calculated at each integration step solving a matrix Riccati equation of order 21x21. The resulting gains are sub-optimal as a full solution for the Hamilton-Jacobi-Bellman equation cannot be resolved in practical terms and some simplifications are taken. Acceleration mechanisms with an -shift is incorporated in the design. As part of the autopilot, a strategy is defined for proper allocation of control effort between canard and tail channels. This is achieved with an augmented feed forward controller that minimizes the total control effort of the missile to maneuver. The feedforward law also maintains the missile near trim conditions, obtaining a well manner response of the missile. The nonlinear controller proves to eliminate the non-minimum phase effect of the tail. Two guidance and control designs have been considered in this Thesis: the Two- Loop and the Integrated approaches. In the Two-Loop approach, the autopilot is placed in an inner loop and designed separately from an outer guidance loop. This structure assumes that spectral separation holds, meaning that the autopilot response times are much higher than the guidance command updates. The developed nonlinear autopilot is linked in the study to an optimal guidance law. Simulations are carried on launching close to collision course against supersonic and highly maneuver targets. Results demonstrate a large boost in performance provided by the dual control versus more traditional canard and tail missiles, where interception with the dual control close to collision course is achieved form 365deg all around the target. It is shown that for the dual control missile the optimal flight strategy results in using opposite control in its approach to target and quick corrections with divert just before impact. However the Two-Loop logic fails to achieve target interception when there are large deviations initially from collision course. One of the reasons is that part of the guidance command is not followed, because the missile is not able to control its axial acceleration without a throttleable engine. Also the separation hypothesis may not be applicable for a high dynamic vehicle like a dual control missile approaching a maneuvering target. If the guidance and autopilot are combined into a single loop, the guidance law will have information of the missile states and could calculate the most optimal approach to the target considering the actual capabilities and attitude of the missile. A third contribution of this Thesis is the resolution of the mentioned second design, the non-linear integrated guidance and autopilot (IGA) problem for the dual control missile. Previous approaches in the literature have posed the problem in body axes, resulting in high unstable behavior due to the low damping of the missile, and have also caused the missile to slide around the target and not actually hitting it. The IGA system is posed here in inertial axes and quaternion dynamics, eliminating these inconveniences. It is not restricted to the missile short term dynamic, and we have explicitly included the missile speed as a state variable. The IGA formulation is also independent of the target maneuver model that is explicitly included in the Two-loop optimal guidance law model. A typical problem of the integrated systems with a proportional control law is the problem of scales. The guidance errors are larger than missile state errors during most of the flight and result in high gains, control saturation and loss of control. It has been addressed here with an integrated feedforward controller that defines a local equilibrium state at each flight point and the controller acts as a regulator to minimize the IGA states excursions versus the defined feedforward state. The performance criteria for the IGA are the same as in the Two-Loop case. However the resulting optimization problem is mathematically very complex. The optimal problem in a finite-time horizon results in an irresoluble state dependent differential Riccati equation with terminal conditions. With a change of variable and the introduction of a transition matrix, the equation is transformed into a time differential Lyapunov equation that can be solved with known numerical methods in real time. This solution results range limited, and applicable when the missile is in a close neighborhood of the target. For larger ranges, an approximate solution is used, obtained from solution of an algebraic matrix Riccati equation at each integration step. The results obtained show, by mean of several comparative numerical tests in diverse homing scenarios, than the integrated approach is a better solution that the Two- Loop scheme. Trajectories obtained are very different in the two cases. The IGA fully preserves the guidance command and it is able to maximize the utilization of the missile propulsion system, achieving interception with lower miss distances and in lower flight times. The IGA can achieve interception against off-boresight targets where the Two- Loop was not able to success. As an additional advantage, the IGA also requires one order of magnitude less calculations than the Two-Loop solution. The effects of radar noises, discrete radar data and radome errors are investigated. IGA solution is robust, and less affected by radar than the Two-Loop, especially because the target maneuvers are not part of the IGA core optimization loop. Estimation of target acceleration is always imprecise and noisy and degrade the performance of the two-Loop solution. The IGA trajectories are such that minimize the impact of radome errors in the guidance loop. Finally, as a fourth contribution, it is demonstrated that the missile with IGA guidance is capable of performing a defense against attacks from its rear hemisphere, as a tail attack, only with aerodynamic control. The studied trajectories have a preprogrammed high rate turn maneuver, maintaining the missile within its controllable envelope. This solution does not recur to more complex features in service today, like vector control of the missile thrust or side thrusters. In all the mathematical treatments and demonstrations, the Kronecker product has been introduced as a practical tool to handle the state dependent parametrizations that have resulted in very high order matrix equations.
Resumo:
Debido al gran auge en las comunicaciones mviles, los terminales cada vez son ms finos a la par que ms grandes, pues cada vez los usuarios quieren tener terminales delgados pero con pantallas mayores. Por ello, el objetivo principal del proyecto es aprender y analizar las antenas usadas en los telfonos mviles, concretamente las antenas impresas. En los ltimos aos con el aumento de los servicios ofrecidos por los terminales mviles se han ido aadiendo distintas bandas de frecuencia en las que trabajan estos terminales. Por ello, ha sido necesario disear antenas que no funcionen nicamente en una banda de frecuencia, sino antenas multibanda, es decir, antenas capaces de funcionar en las distintas bandas de frecuencias. Para realizar las simulaciones y pruebas de este proyecto se utiliz el software FEKO, tanto el CAD FEKO como el POST FEKO. El CAD FEKO se emple para el diseo de la antena, mientras que el POST FEKO sirvi para analizar las simulaciones. Por ltimo, hay que aadir que FEKO aunque est basado en el Mtodo de los Momentos (MoM) es una herramienta que puede utilizar varios mtodos numricos. Adems del MoM puede utilizar otras tcnicas (por separado o hibridizadas) como son el Mtodos de Elementos Finitos (FEM), ptica Fsica (PO), Lanzamiento de rayos con ptica Geomtrica (RL-GO), Teora Uniforme de la Difraccin (UTD), Mtodo de las Diferencias Finitas en el Dominio del Tiempo (FDTD), ... ABSTRACT. Because of the boom in mobile communications, terminals are thinner and so large, because users want to thin terminals but with large screens. Therefore, the main objective of the project is to learn and analyse the antennas used in mobile phones, specifically printed antennas. In recent years with the rise of the services offered by mobile terminals have been adding different frequency bands in which these terminals work. For that reason, it has been necessary to design antennas that not work only in a frequency band, but multiband antennas, i.e., antennas capable of operating in different frequency bands. For performing simulations and testing in this project will be used software FEKO, as the CAD FEKO and POST FEKO. The CAD FEKO is used for the design of the antenna, whereas the POST FEKO is used for simulation analysis. Finally, it has to add that FEKO is based on the Method of Moments (MoM) but also it can use several numerical methods. Besides the MoM, FEKO can use other techniques (separated or hybridized) such as the Finite Element Method (FEM), Physical Optics (PO), Ray-launching Geometrical Optics (RL-GO), Uniform Theory of Diffraction (UTD), Finite Difference Time Domain (FDTD)
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Intercontinental Ballistic Missiles are capable of placing a nuclear warhead at more than 5,000 km away from its launching base. With the lethal power of a nuclear warhead a whole city could be wiped out by a single weapon causing millions of deaths. This means that the threat posed to any country from a single ICBM captured by a terrorist group or launched by a 'rogue' state is huge. This threat is increasing as more countries are achieving nuclear and advanced launcher capabilities. In order to suppress or at least reduce this threat the United States created the National Missile Defense System which involved, among other systems, the development of long-range interceptors whose aim is to destroy incoming ballistic missiles in their midcourse phase. The Ballistic Missile Defense is a high-profile topic that has been the focus of political controversy lately when the U.S. decided to expand the Ballistic Missile system to Europe, with the opposition of Russia. However the technical characteristics of this system are mostly unknown by the general public. The Interception of an ICBM using a long range Interceptor Missile as intended within the Ground-Based Missile Defense System by the American National Missile Defense (NMD) implies a series of problems of incredible complexity: - The incoming missile has to be detected almost immediately after launch. - The incoming missile has to be tracked along its trajectory with a great accuracy. - The Interceptor Missile has to implement a fast and accurate guidance algorithm in order to reach the incoming missile as soon as possible. - The Kinetic Kill Vehicle deployed by the interceptor boost vehicle has to be able to detect the reentry vehicle once it has been deployed by ICBM, when it offers a very low infrared signature, in order to perform a final rendezvous manoeuvre. - The Kinetic Kill Vehicle has to be able to discriminate the reentry vehicle from the surrounding debris and decoys. - The Kinetic Kill Vehicle has to be able to implement an accurate guidance algorithm in order to perform a kinetic interception (direct collision) of the reentry vehicle, at relative speeds of more than 10 km/s. All these problems are being dealt simultaneously by the Ground-Based Missile Defense System that is developing very complex and expensive sensors, communications and control centers and long-range interceptors (Ground-Based Interceptor Missile) including a Kinetic Kill Vehicle. Among all the technical challenges involved in this interception scenario, this thesis focuses on the algorithms required for the guidance of the Interceptor Missile and the Kinetic Kill Vehicle in order to perform the direct collision with the ICBM. The involved guidance algorithms are deeply analysed in this thesis in part III where conventional guidance strategies are reviewed and optimal guidance algorithms are developed for this interception problem. The generation of a realistic simulation of the interception scenario between an ICBM and a Ground Based Interceptor designed to destroy it was considered as necessary in order to be able to compare different guidance strategies with meaningful results. As a consequence, a highly representative simulator for an ICBM and a Kill Vehicle has been implemented, as detailed in part II, and the generation of these simulators has also become one of the purposes of this thesis. In summary, the main purposes of this thesis are: - To develop a highly representative simulator of an interception scenario between an ICBM and a Kill Vehicle launched from a Ground Based Interceptor. -To analyse the main existing guidance algorithms both for the ascent phase and the terminal phase of the missiles. Novel conclusions of these analyses are obtained. - To develop original optimal guidance algorithms for the interception problem. - To compare the results obtained using the different guidance strategies, assess the behaviour of the optimal guidance algorithms, and analyse the feasibility of the Ballistic Missile Defense system in terms of guidance (part IV). As a secondary objective, a general overview of the state of the art in terms of ballistic missiles and anti-ballistic missile defence is provided (part I).
Resumo:
El panorama global est cambiando, y esto influye sobre la forma en la que entendemos y tratamos de alcanzar un desarrollo humano sostenible. El crecimiento de la poblacin conlleva una mayor presin sobre los recursos, pero tambin supone una mayor cantidad de mano de obra y de talento; la concentracin en reas urbanas est cambiando las dinmicas sociales y desafiando los canales de comercializacin tradicionales, pero tambin genera nuevos mercados y fomenta la innovacin; los cambios en la economa global estn reduciendo los tradicionales desequilibrios de poder entre los pases occidentales y el resto del mundo; y las crecientes interconexiones crean nuevos riesgos pero tambin oportunidades para lanzar iniciativas de alcance global. Todas estas tendencias nos estn obligando a repensar qu es el desarrollo humano y de qu manera deberamos afrontar el reto de la pobreza. Es comnmente aceptado que la globalizacin implica interdependencia y que, para conseguir un desarrollo humano sostenible, la colaboracin entre actores de distintos mbitos es necesaria. Se observa una creciente convergencia de temas, intereses y soluciones en torno al desarrollo sostenible, incluso en diferentes pases y sectores, lo que est facilitando la colaboracin estratgica entre empresas, gobiernos y sociedad civil. Existen pocas duda a da de hoy sobre el papel fundamental que las empresas deben desempear en la transicin mundial hacia la sostenibilidad ambiental y la erradicacin de la pobreza. Las empresas estn evolucionando desde un enfoque tradicional centrado en la maximizacin de beneficios econmicos hacia un enfoque holstico que integra la sostenibilidad y la responsabilidad social como parte del ncleo de negocio de las compaas. En el mbito medioambiental, muchas empresas ya han comenzado a actuar y tratan de reducir sus emisiones, sus desechos y su consumo de energa. Sin embargo la contribucin de las empresas a la reduccin de la pobreza no est tan clara. Actualmente en torno a 1,2 miles de millones de personas viven en situacin de extrema pobreza. La mayora de estas personas an vive en zonas rurales donde la mayor parte de la poblacin activa trabaja en el sector agrcola. Por lo tanto, mejorar las oportunidades y reducir los riesgos de los productores ms vulnerables en el sector de la agricultura puede ser un motor de desarrollo rural y reduccin de la pobreza, especialmente en pases de bajo nivel de desarrollo cuyas economas estn fundamentalmente basadas en la agricultura. Algunas empresas comienzan a incluir a los pobres en sus operaciones como consumidores, proveedores y emprendedores. Esta tesis se centra en las potenciales oportunidades relacionadas con la incorporacin sostenible de los pobres como proveedores de productos y/o de mano de obra. La colaboracin entre empresas y productores vulnerables de pases en desarrollo es un tema relativamente nuevo y todava poco estudiado. La pregunta que gua esta tesis es: Cmo pueden las empresas facilitar la inclusin sostenible en cadenas de suministro de productores vulnerables de los pases menos desarrollados?. Para responder a la pregunta anterior, la autora ha aplicado una metodologa de casos de estudio. Esta metodologa se considera apropiada porque la investigacin sobre cadenas de suministro inclusivas es todava escasa y porque es necesario entender en profundidad un fenmeno de la vida real, y para ello es fundamental conocer su contexto. En primer lugar, se realiza una revisin de literatura para identificar las proposiciones y los constructos tericos que guiarn la posterior recogida de datos. La revisin de literatura se divide en dos partes: una ms general que explora la dimensin social de la sostenibilidad en cadenas de suministro, y una ms especfica que se centra en la incorporacin de los pobres como proveedores en cadenas de suministro. A lo largo de la ltima dcada, ha habido un crecimiento exponencial de los estudios acadmicos sobre la sostenibilidad de las cadenas de suministro, pero la mayora de los esfuerzos se han dirigido hacia la dimensin medioambiental de la sostenibilidad. Por lo tanto la revisin de literatura, que se presenta en la Seccin 3.1 (pgina 35) y que profundiza en la sostenibilidad social de las cadenas de suministro, puede considerarse una contribucin en s misma. Esta revisin de literatura revela que la investigacin sobre aspectos sociales en cadenas de suministro est cobrando impulso en distintas reas de conocimiento, principalmente en los mbitos de investigacin sobre gestin de cadenas de suministro, responsabilidad social corporativa y estudios del desarrollo. La investigacin existente sobre sostenibilidad social de cadenas de suministro se centra en tres temas: aclarar la definicin de sostenibilidad social; analizar la implementacin de estrategias de sostenibilidad social en cadenas de suministro; y estudiar el apoyo de las em presas lderes a proveedores vulnerables para facilitar su transicin hacia la sostenibilidad. Un marco conceptual que resume los principales hallazgos de esta primera parte de la revisin de literatura es planteado en la Figura 7 (pgina 48). No obstante, en el rea de investigacin que est emergiendo en torno a la sostenibilidad social de las cadenas de suministro, los estudios relacionados con la reduccin de la pobreza son an escasos. Adems se aprecia una falta de contribuciones desde y sobre los pases menos desarrollados, as como una clara tendencia a reflejar la visin de las empresas lderes de las cadenas de suministro, olvidando la perspectiva de los proveedores. La segunda parte de la revisin de literatura presentada en la Seccin 3.2 (pgina 51) profundiza en tres lneas de investigacin que exploran, desde distintas perspectivas, la inclusin de los pobres en cadenas de suministro. Estas lneas son Global Value Chains (GVC), Base of the Pyramid (BoP) y Sustainable Supply Chain Management (SSCM). La investigacin en GVC analiza las cadenas de suministro desde la perspectiva de la globalizacin econmica y el comercio internacional, poniendo especial nfasis en las implicaciones para los pases en desarrollo y las comunidades vulnerables. GVC caracteriza las cadenas de suministro segn la forma en la que son gobernadas, las oportunidades de mejora que existen para los productores que forman parte de la cadena y el grado de inclusin o exclusin de las comunidades ms pobres y vulnerables. La investigacin en BoP explora las relaciones comerciales entre empresas y comunidades pobres. La premisa fundamental del concepto BoP es la posibilidad de combinar la generacin de beneficios con la reduccin de la pobreza. La propuesta original es que mediante la venta de productos y servicios a las comunidades pobres de pases en desarrollo, la pobreza puede ser reducida al tiempo que las empresas incrementan sus beneficios, especialmente las grandes empresas multinacionales. Esta idea ha ido evolucionando y, a da de hoy, los investigadores BoP consideran la incorporacin de los pobres no slo como consumidores sino tambin como empleados, proveedores y co-creadores. La investigacin en SSCM ha estado fundamentalmente orientada al estudio de la dimensin medioambiental de la sostenibilidad de cadenas de suministro. Sin embargo, la creciente externalizacin de la produccin a pases en desarrollo y las demandas de los grupos de inters para que las empresas aborden todos los aspectos de la sostenibilidad han llevado a los acadmicos de SSCM a reconocer la importancia de integrar asuntos relacionados con la reduccin de la pobreza en sus investigaciones. Algunos estudios comienzan a apuntar los principales retos a los que se enfrentan las empresas para colaborar con productores vulnerables en sus cadenas de suministro. Estos retos son: falta de comunicacin, altos costes de transaccin y el incremento de la complejidad de las operaciones. Las contribuciones de estas tres lneas de investigacin son complementarias para el estudio de las cadenas de suministro inclusivas. Sin embargo, raramente han sido consideradas conjuntamente, ya que pertenecen a mbitos de conocimiento distintos. Esta tesis integra las aportaciones de GVC, BoP y SSCM en un marco conceptual para la creacin y gestin de cadenas de suministro inclusivas. Este marco conceptual para cadenas de suministro inclusivas queda representado en la Figura 9 (pgina 68). El marco conceptual refleja las motivaciones que llevan a las empresas a colaborar con productores vulnerables, los retos a los que se enfrentan al hacerlo, y los caminos o estrategias que estn siguiendo para construir y operar cadenas de suministro inclusivas de manera que sean beneficiosas tanto para la empresa como para los productores vulnerables. A fin de validar y refinar el marco conceptual propuesto, tres casos de estudio se llevan a cabo. Las cadenas de suministro analizadas por los casos de estudio pertenecen al sector agrcola y sus principales proveedores se encuentran en pases de frica subsahariana. Mltiples mtodos de recoleccin de datos y triangulacin son utilizados para mejorar la fiabilidad de los datos. La autora desarroll trabajos de campo en Senegal, Etiopa y Tanzania. Estos viajes permitieron enriquecer el proceso de recogida de informacin mediante entrevistas semiestructuradas y conversaciones informales con los principales actores de la cadena de suministro y mediante la observacin directa de los procesos y las interacciones entre productores vulnerables y empresas. El Caso de estudio A (Seccin 5.1 en pgina 96) es un caso de estudio nico. Analiza la cadena de suministro local de verduras en Senegal. La organizacin focal es Manobi, una empresa senegalesa que provee servicios de bajo coste a emprendedores locales del sector agrcola. El Caso de estudio A proporciona un interesante anlisis del funcionamiento de una cadena de suministro local en un pas en desarrollo y muestra como la provisin de servicios profesionales puede mejorar el desempeo de productores vulnerables. El Caso de estudio B (Seccin 5.2 en pgina 122) es un caso de estudio nico. Analiza la cadena de suministro global de flor cortada con origen en Etiopa. La organizacin focal es EHPEA, la Asociacin Etope de Productores y Exportadores Hortcolas, cuya misin es promover y salvaguardar la posicin competitiva del sector agrcola etope en el mercado global. El Caso de estudio B ayuda a comprender mejor la perspectiva de los proveedores respecto a los requerimiento de sostenibilidad del mercado global. Tambin muestra cmo la inclusin de los productores en el proceso de desarrollo de un estndar privado facilita su implementacin posterior. El Caso de estudio C (Seccin 5.3 en pgina 143) es un caso de estudio mltiple. Analiza la cadena de suministro global de caf especial con origen en Tanzania. Las organizaciones focales son comerciantes que conectan de manera directa a pequeos agricultores de caf en pases en desarrollo con empresas tostadoras de caf en pases desarrollados. El Caso de estudio C muestra cmo un pequeo agricultor puede proveer un producto premium al mercado global, y participar en un segmento diferenciado del mercado a travs de una cadena de suministro transparente y eficiente. Las aportaciones empricas de los casos de estudio ayudan a validar y mejorar el marco conceptual sobre cadenas de suministro inclusivas (ver discusin en el Captulo 6 en pgina 170). El resultado es la propuesta de una nueva versin del marco conceptual representado en la Figura 40 (pgina 195). Los casos de estudio tambin proporcionan interesantes aportaciones en relacin a la gestin de cadenas de suministro inclusivas y muestran las perspectivas de distintos actores implicados. Esta tesis arroja luz sobre el papel de las empresas en la creacin y la gestin de cadenas de suministro inclusivas llevando a cabo una revisin de literatura multidisciplinar y analizando tres casos de estudio en pases africanos. Como resultado, esta tesis presenta una serie de contribuciones empricas y tericas al mbito de investigacin emergente en torno a las cadenas de suministro inclusivas (Captulo 7). Esta tesis tambin pretende ser til a profesionales que deseen facilitar la incorporacin de los pobres como proveedores en condiciones justas y beneficiosas. ABSTRACT The global outlook is changing, and this is influencing the way we understand and try to achieve sustainable human development. Population growth entails increasing pressure over resources, but it also provides greater workforce and talent; concentration in urban areas is changing social dynamics and challenging traditional marketing channels, but also creating news markets and driving innovation; the global economy shift is rebalancing the traditional power imbalance between Western countries and the rest of the world, making new opportunities to arise; and interconnections and global interdependence create new risks but also opportunities for launching initiatives with a global reach. All these trends are impelling us to rethink what development is and in which way poverty alleviation should be approached. It is generally agreed that globalization implies interdependence and, in order to achieve sustainable human development, collaboration of all actors is needed. A convergence of issues, interests and solutions related to sustainable development is being observed across countries and sectors, encouraging strategic collaboration among companies, governments and civil society. There is little doubt nowadays about the crucial role of the private sector in the worlds path towards environmental sustainability and poverty alleviation. Businesses are evolving from a business as usual stance to a more sustainable and responsible approach. In the environmental arena, many companies have already walk the talk, implementing environmental management systems and trying to reduce emissions and energy consumption. However, regarding poverty alleviation, their contribution is less clear. There are around 1.2 billion people living in extreme poverty. Most of this people still live in rural areas where the agricultural sector employs a big part of the active population. Therefore, improving opportunities and reducing risks for vulnerable producers in the agri-food sector can be a primary engine of rural development and poverty alleviation, particularly in the poor, agriculture-based economies of least developed countries. Some companies are beginning to include the poor into their operations as consumers, suppliers and entrepreneurs. This thesis focuses specifically on the potential opportunities related to the sustainable incorporation of the poor as suppliers of products and/or labor. Business collaboration with vulnerable producers in developing countries is a relatively new trend and it is still understudied. The overall question guiding this thesis is: How can businesses facilitate the sustainable inclusion of vulnerable producers from least developed countries into supply chains?. In order to answer the research question, the author has applied a case study research strategy. This methodology is considered appropriate because research about inclusive supply chains is still at an early stage, and because there is a need to understand a real-life phenomenon in depth, but such understanding encompasses important contextual conditions. First, a literature review is conducted, in order to identify the research propositions and theoretical constructs that will guide the data collection. The literature review is divided in two parts: a more general one that explores the social dimension of sustainability of supply chains, and a more specific one that focuses on the incorporation of the poor as suppliers in supply chains. During the last decade, there has been an exponential growth of studies in the field of supply chain sustainability, but research efforts have traditionally been directed towards the analysis of the environmental dimension. Therefore, the literature review presented in Section 3.1 (page 35) that delves into social sustainability of supply chains can be considered a contribution in itself. This literature review reveals that the investigation of social issues in supply chains is gaining momentum and comes from different academic disciplines, namely Supply Chain Management, Corporate Social Responsibility and Development Studies. Existing research about social sustainability of supply chains focuses on three issues: clarify the definition of social sustainability; analyze the implementation of social sustainability strategies in supply chains; and study lead companies support to vulnerable suppliers in their transition towards sustainability. A conceptual framework that outlines the main findings that emerge from this first part of literature review is proposed in Figure 7 (page 48). Nevertheless, in this nascent field of social sustainability of supply chains, studies related to poverty alleviation are still scarce. Moreover, a lack of contributions from and about least developed countries has been observed, as well as a tendency to reflect on the lead firms standpoint, neglecting the suppliers perspective. The second part of the literature review (Section 3.2 in page 51) delves into three research streams that are exploring the inclusion of the poor into supply chains from different viewpoints. These research streams are Global Value Chains (GVC), Base of the Pyramid (BoP) and Sustainable Supply Chain Management (SSCM). GVC research discusses the dynamics of economic globalization and international trade, putting special emphasis in the implications for developing countries and vulnerable communities. GVC characterizes supply chains by the way they are governed, the upgrading opportunities that exist for producers in the chain and the degree of inclusion or exclusion of impoverished communities. BoP research explores trading relationships between businesses and impoverished communities. The core premise of the BoP concept is the possibility to combine profits with poverty alleviation. The original BoP proposition is that by marketing innovative products and services to poor communities in developing countries, poverty would be reduced and companies would increase their benefits, especially multinational companies. This idea has evolved to consider the incorporation of the poor to business activities not only as consumers, but also as employees, entrepreneurs and co-creators. The SSCM school of thought has mainly focused on studying the environmental dimension of supply chain sustainability, neglecting the consideration of the social perspective. However, in recent years, increasing outsourcing of production to developing countries and stakeholders demands for a more holistic approach to business sustainability have led SSCM scholars to acknowledge the importance of integrating poverty concerns in this fields research agenda. Some SSCM studies identify the main operational challenges for companies which engage with vulnerable suppliers in their supply chains: missing communication, higher transactional and operational costs and increased complexity. Contributions from these three research streams are complementary for the study of inclusive supply chains. However, they have been rarely considered together, since they belong to different research areas. This thesis seeks to play a dovetailing role in this scenario by proposing a conceptual framework for creating and operating inclusive supply chains that builds on contributions from GVC, SSCM and BoP research. This framework for inclusive supply chains is depicted in Figure 9 (page 68), and explains the motivations that drive businesses to collaborate with vulnerable suppliers, the chal lenges they face in doing so, and the pathways they are following in order to build and operate inclusive supply chains profitably for both buying companies and vulnerable suppliers. In order to validate and refine the proposed framework, three case studies are carried out. The supply chains analyzed by the case studies belong to the agri-food sector and source from Sub-Saharan African countries. Multiple data collection methods and triangulation are used in order to improve reliability of findings. The author carried out field work in Senegal, Ethiopia and Tanzania. These travels enriched the data collection process, providing semi-structured interviews and informal conversations with the main actors in the supply chains, as well as direct observation of processes and interactions among companies and vulnerable suppliers. Case study A (Section 5.1 in page 96) is a single case study. It analyzes a local supply chain in Senegal providing vegetables to the local market. The focal organization is Manobi, a Senegalese inclusive business which provides affordable ICT services to local entrepreneurs in the agri-food sector. Case study A provides interesting insights into the dynamics of local supply chains and how professional services can help to improve their performance. Case study B (Section 5.2 in page 122) is a single case study. It analyzes a global supply chain with origin in Ethiopia providing cut flowers to the global commodity market. The focal organization is EHPEA, Ethiopian Horticulture Producers and Exporters Association, whose mission is to promote and safeguard the competitive position of the Ethiopian horticulture sector within the global market. Case study B helps to better understand the suppliers perspective regarding global market sustainability requirements and shows how the inclusion of suppliers in the process of development of a private standard has a positive impact in its implementation. Case study C (Section 5.3 in page 143) is a multiple case study. It analyzes a global supply chain with origin in Tanzania providing coffee to the global niche market of specialty coffee. The focal organizations are traders who are directly connecting smallholder coffee farmers in developing countries to coffee roasters in developed countries. Case study C shows how smallholder farmers can supply a premium product and be incorporated in a differentiated market segment through a transparent and efficient supply chain. The empirical findings from the case studies help to validate and refine the conceptual framework (see discussion in Chapter 6). The proposal of a new version of the conceptual framework is depicted in Figure 40 (page 195). The case studies also provide interesting insights related to the management of inclusive supply chains and show the perspectives of the different actors involved. This thesis sheds some light on the role of businesses in the creation and operation of inclusive supply chains by carrying out a cross-disciplinary literature review and analyzing three case studies in African countries. In doing so, this thesis presents a series of theoretical and empirical contributions to the emerging academic field of inclusive supply chains (Chapter 7). This thesis also intends to be useful to practitioners willing to improve the incorporation of the poor as suppliers in fair and profitable conditions.
Resumo:
Como no pocos proyectos, el origen de esta tesis es fruto de una casualidad. Hace unos aos me top en Londres, en la librera Walden Books del 38 de Harmood St., con una primera edicin de la conocida monografa de Mies a cargo de Philip Johnson. El librito, en realidad catlogo de la exposicin que en 1947 el MoMA de Nueva York dedicara a la obra de Mies Van der Rohe a los diez aos del desembarco del arquitecto en Estados Unidos, tiene un tamao de 10 x 7,5 pulgadas, es decir, la mitad del formato americano Crown (20x15 pulgadas), equivalente a 508 x 381 mm. Se imprimieron, en su primera tirada, editada por The Plantin Press, 12.000 ejemplares. Ese mismo ao, con edicin al cuidado de Reynal y Hitchcock, se publicara la primera traduccin al ingls de Cuando las catedrales eran blancas de Le Corbusier y una seleccin de poemas de Lorca, siete aos despus de su Poeta en Nueva York. En la monografa, en la pgina 109, aparece el conocido croquis de Mies Sketch for a glass house on a hillside. c. 1934, escasamente unas lneas, aunque precisas y llenas de matices, de la casa en una ladera que rpidamente nos remite a aquella primera propuesta de Saarinen para una casa en el aire, primero en 1941 en Pensilvania y despus, en 1945, con Charles Eames, en Los Angeles, que nunca llegaran a construirse, sino en su aliteraciones posteriores realizadas por Harry Seidler (Julian Rose House, Wahroonga, Sydney, 1949), Philip Johnson (Leonhardt house, Long Island, Nueva York, 1956) o Craig Ellwood (Smith House, Crestwood Hills, 1958; Frank & Polly Pierson House, Malib, 1962; Chamorro House, Hollywood Hills, 1963, o la serie Weekend House, con Gerald Horn, entre 1964 y 1970, hasta el magnfico Art Center College of Design de Pasadera, su puente habitado de 1977). El relato que da origen al texto discurre en un estricto perodo de tiempo, desde los primeros dibujos de la Case Study House n8, dentro del programa promovido por John Entenza y su revista Arts & Architecture en California, realizados en el estudio de Saarinen en Bloomfield Hills, Michigan, hasta que el proyecto de la casa Eames finaliza cinco aos despus de acabar la obra en 1955, en la versin conocida, radicalmente distinta al proyecto original, cuando la pareja Charles y Ray Eames edita el corto House After Five Years of Living. La discusin original en torno a esta casita, o mejor, a las circunstancias, casualidades controladas, que rodean su construccin, se produce estrictamente cuando rastreamos aquellos invariantes que se mantienen en las dos versiones y las reconcilian. En este corto perodo de tiempo se producen en el proyecto una serie de decisiones que permiten descubrir, tanto en la forma como en el mismo proceso transformador del proyecto, en su obsesivo registro, en los nuevos referentes asumidos y propuestos, la primera visibilidad del cambio del paradigma moderno. Pero este momento germinal que cristaliza el paso a la postmodernidad no es indito en la historia de la arquitectura americana. As, el relato abre su mbito temporal hasta un nuevo perodo de cincuenta aos que arranca en 1893, ao de la celebracin en Chicago de la Exposicin Internacional Colombina. En la White City de Hunt & McKim y del traidor Burham, Louis Sullivan construye su Golden Doorway en el pabelln de los Transportes. Aquella que visitar Adolf Loos antes de volver, renovado, a Viena; la misma que admirar Andr Bouillet, representante de la Union Centrale des Arts Decoratifs de Paris, y que deslumbrar en los museos de toda Europa, de Pars a Mosc en grandes fotografas y maquetas. Hasta que en Finlandia alguien muestra una de esas fotografas a un joven estudiante de diecinueve aos en el Instituto Politcnico. Eliel Saarinen queda fascinado por la poderosa novedad de la imagen. Cuelga la fotografa frente a su tablero de dibujo, consciente de que la Golden Doorway, esa puerta de la aventura y la catarsis que Sullivan acuara como distintivo y que resolvera como nico elemento complejo sus proyectos ms maduros, desprovistos de todo ornamento; la misma que repetiran ms tarde, con profundo reconocimiento, Ladovsky, Wright, Scarpa o Moneo, puerta dentro de puerta, fuelle y umbral, contena, en sus propias palabras emocionadas, todo el futuro de la arquitectura. Desde ah, pasando por el ao 1910, momento de la huida de Wright a La Toscana y el descubrimiento de su arquitectura en Europa, entre otros por un joven Mies van der Rohe, meritorio en el estudio de Peter Behrens, a travs del Wasmuth Portfolio; y as como algo despus, en 1914, Schindler y en 1923 Neutra, harn el camino inverso, hasta que Mies les siga en 1937, animado por un Philip Johnson que haba viajado a Europa en 1930, volviendo a 1945 y el inicio del programa Case Study House en California, hasta 1949, momento de la construccin de la CSH#8, y, por fin, al ao 1955, after 5 years of living, en el que Julius Shulman fotografa la casa de Ray y Charles Eames en el prado de Chautauqua sobre las Pacific Palisades de Los Angeles, lanzando sus finas lneas amarillas hasta Alison y Peter Smithson y su tardomoderno heroico, hasta el primer Foster y su potico hightech y hasta el O-riginal Ghery, deconstruyendo el espacio esencial de su casa desde el espacio mismo, abiertas ya las puertas al nuevo siglo. Y en estos cambios de paradigma, desde el rgido eclecticismo de los estilos al lirismo moderno en el gozne secular y de ah a la frivolidad, ligereza, exhibicionismo y oportunismo cultos del hecho postmoderno, hay algo que se mantiene invariante en los bandazos de la relacin del hombre contemporneo con su entorno. Como la escultura, que segn Barnett Newman no es sino aquello contra lo que uno choca cuando retrocede para mirar un cuadro, en estos prstinos lugares, comunes y corrientes, recorrido, puerta, umbral, recinto y vaco, te topas con la arquitectura antes de darte cuenta de que es arquitectura. ABSTRACT As with many other projects, the origin of this doctoral thesis is the result of a chance. A few years ago I found in a bookstore in London, 38 Harmood st., Walden Books, a first edition of the well-known monograph about Mies by Philip Johnson. The tiny book, in fact a catalog of the exhibition that the MoMA of New York devoted to the work of Mies van der Rohe in 1947, ten years after his landing in the United States, has a size of 10 x 7.5 inches, that is, half of Crown American format (20 x 15 inches), equivalent to 508 x 381 mm. In the first printing, published by The Plantin Press, 12,000 copies were released. That same year, produced by Reynal and Hitchcock, both the first English translation of When the cathedrals were white by Le Corbusier and a selection of poems by Lorca were published, seven years after his Poet in New York. Inside the book, the famous drawing from Mies Sketch for a glass house on a hillside c. 1934 appears on page 109, barely a few lines, precise and nuanced though, the house on a hillside that quickly reminds us of the proposals of Eero Saarinen for a house in the air, first in 1941, in Pennsylvania, and later, in 1945, with Charles Eames, in Los Angeles, that would never be built, but in their later alliterations made by Harry Seidler (Julian Rose House, Wahroonga, Sydney, 1949), Philip Johnson (Leonhardt house, Long Island, New York, 1956) or Craig Ellwood (Smith House, Crestwood Hills, 1958; Frank Pierson & Polly House, Malibu, 1962, Chamorro House, Hollywood Hills, 1963, or the Weekend House series, with Gerald Horn, between 1964 and 1970, to the magnificent Art Center College of Design Pasadena, the inhabited bridge, in 1977). The story that gives rise to the text flows in a short amount of time, from the first drawings of the Case Study House No. 8, within the program promoted by John Entenza and his magazine Arts & Architecture in California, made in the study of Saarinen in Bloomfield Hills, Michigan, until the project of the Eames house is completed five years after finishing the construction in 1955, in the final version we know, radically different from the initial state, when the couple, Charles and Ray, published the film House after Five Years of Living. The original discussion around this house, or better, about the circumstances, controlled coincidences, regarding its construction, appears when one takes account of those that remain, the invariants, in the two versions, drawn and built, which precisely allow the reconciliation between both projects. In this short period of time a series of decisions made in the transformation process of the project reveal, in the obsessive record made by Charles Eames and in the new proposed references, the first visibility of the changing of the modern paradigm. But this germinal moment that crystallizes the transition to postmodernism is not unprecedented in the history of American architecture. So, the story opens its temporal scope to a fifty-year period that started in 1893, date of the celebration of the Chicago Worlds Columbian Exposition. In the White City by Hunt & McKim and Burnham, the traitor, Louis Sullivan builds his Golden Doorway in the Transportation Building. That visited by a renovated Adolf Loos before his coming back to Vienna; the same that Andr Bouillet, Head of the Union Centrale des Arts Decoratifs in Paris, admired and dazzled in museums all over Europe, from Paris to Moscow, in large photographs and models. Until someone in Finland showed one of those photos to a young nineteen-years-old student at the Polytechnic Institute. Eliel Saarinen became fascinated by the powerful new image: he hanged the picture in front of his drawing board, aware that the Golden Doorway, that door of adventure and catharsis Sullivan coined as distinctive and as a single complex element which would solve their most mature projects, devoid of all ornament; the same that would repeat later, with deep appreciation, Ladovsky, Wright, Scarpa, or Moneo, a door inside a door, a threshold, a gap that contained, in its own moving words, the whole future of architecture. From there, through 1910, when Wright's flight to Tuscany allows Europe to discover his architecture, including a young Mies van der Rohe, meritorious in the studio of Peter Behrens, via the Wasmuth Portfolio; and as a little bit later, in 1914, Schindler and Neutra in 1923, made the travel in opposite direction, until Mies follows them in 1937, led by a Philip Johnson who had traveled to Europe in 1930, we return to 1945 and the beginning of the program Case Study House in California, and from 1949, when construction of the CSH # 8 begins, and finally, to 1955, after five years of living, when Julius Shulman photographs the inside of the house with Ray and Charles Eames, and all their belongins, at the Chautauqua meadows on Pacific Palisades in Los Angeles, launching its fine yellow lines to Alison and Peter Smithson and his heroic late modern, up to the first Foster and his poetic hightech and even the O-riginal Gehry, deconstructing the essential space of his home from the space itself, opening the doors to the new century. And these paradigm shifts, from the hard eclectic styles to modern secular lyricism in the hinge and then overcoming the cultured frivolity, lightness, exhibitionism, and opportunism of the postmodern skeptical focus, something remains intense, invariant in the lurching relationship of contemporary man and his environment. As the sculpture, which according to Barnett Newman is what you bump into when you back up to see a painting, in these pristine, ordinary places, promenade, door, threshold, enclosure and emptiness, you stumble upon the architecture even before realizing that it is architecture.
