36 resultados para IT Security, Internet, Personal Firewall, Security Mechanism, Security System, Security Threat, Security Usability, Security Vulnerability
Resumo:
Many neurodegenerative diseases are characterized by malfunction of the DNA damage response. Therefore, it is important to understand the connection between system level neural network behavior and DNA. Neural networks drawn from genetically engineered animals, interfaced with micro-electrode arrays allowed us to unveil connections between networks system level activity properties and such genome instability. We discovered that Atm protein deficiency, which in humans leads to progressive motor impairment, leads to a reduced synchronization persistence compared to wild type synchronization, after chemically imposed DNA damage. Not only do these results suggest a role for DNA stability in neural network activity, they also establish an experimental paradigm for empirically determining the role a gene plays on the behavior of a neural network.
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In this work we propose an image acquisition and processing methodology (framework) developed for performance in-field grapes and leaves detection and quantification, based on a six step methodology: 1) image segmentation through Fuzzy C-Means with Gustafson Kessel (FCM-GK) clustering; 2) obtaining of FCM-GK outputs (centroids) for acting as seeding for K-Means clustering; 3) Identification of the clusters generated by K-Means using a Support Vector Machine (SVM) classifier. 4) Performance of morphological operations over the grapes and leaves clusters in order to fill holes and to eliminate small pixels clusters; 5)Creation of a mosaic image by Scale-Invariant Feature Transform (SIFT) in order to avoid overlapping between images; 6) Calculation of the areas of leaves and grapes and finding of the centroids in the grape bunches. Image data are collected using a colour camera fixed to a mobile platform. This platform was developed to give a stabilized surface to guarantee that the images were acquired parallel to de vineyard rows. In this way, the platform avoids the distortion of the images that lead to poor estimation of the areas. Our preliminary results are promissory, although they still have shown that it is necessary to implement a camera stabilization system to avoid undesired camera movements, and also a parallel processing procedure in order to speed up the mosaicking process.
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A total of 108 eggs from a group of 100 brown laying hens housed in standard cages were analyzed. Thirty-six eggs were retired when the hens had 30 week of age, other 36 eggs were retired when the hens had 35 week of age and the remaining 36 eggs were retired five weeks afterwards. Each group of 36 eggs was radomly divided in three groups of 12 eggs. First group was analyzed at once, second group one was kept during one week in the refrigerator (5C) and third group was kept also one week but on ambient temperature (25C). Shell color, shell thickness, specific gravity, albumen height and Haugh units wre obtained. The bird age had significant effect on shell color and shell thickness, but the storage system had not influence on such variables. The hen age had not effect on specific gravity, but the storage system affected to this variable. Hen age and storage system had significant influence (P<0.05) on albumen height and Haugh units, and the interaction age storage system was significant for these variables. The specific gravity had positive relations with shell thickness, yolk color, albumen height and Haugh units. It is concluded that bird age and storage system under high temperatures reduced the egg quality.
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An approximate analytic model of a shared memory multiprocessor with a Cache Only Memory Architecture (COMA), the busbased Data Difussion Machine (DDM), is presented and validated. It describes the timing and interference in the system as a function of the hardware, the protocols, the topology and the workload. Model results have been compared to results from an independent simulator. The comparison shows good model accuracy specially for non-saturated systems, where the errors in response times and device utilizations are independent of the number of processors and remain below 10% in 90% of the simulations. Therefore, the model can be used as an average performance prediction tool that avoids expensive simulations in the design of systems with many processors.
Resumo:
Lpdoc is an automatic program documentation generator for (C)LP systems. Lpdoc generates a reference manual automatically from one or more source files for a logic program (including ISO-Prolog, Ciao, many CLP systems, ...). It is particularly useful for documenting library modules, for which it automatically generates a description of the module interface. However, lpdoc can also be used quite successfully to document full applications and to generate nicely formatted plain ascii "readme" files. A fundamental advantage of using lpdoc to document programs is that it is much easier to maintain a true correspondence between the program and its documentation, and to identify precisely to what version of the program a given printed manual corresponds. The quality of the documentation generated can be greatly enhanced by including within the program text: assertions (types, modes, etc. ...) for the predicates in the program, and machine-readable comments (in the "literate programming" style). The assertions and comments included in the source file need to be written using the Ciao system assertion language. A simple compatibility library is available to make traditional (constraint) logic programming systems ignore these assertions and comments allowing normal treatment of programs documented in this way. The documentation is currently generated in HTML or texinf o format. From the texinf o output, printed and on-line manuals in several formats (dvi, ps, info, etc.) can be easily generated automatically, using publicly available tools, lpdoc can also generate 'man' pages (Unix man page format) as well as brief descriptions in html or emacs info formats suitable for inclusion in an on-line index of applications. In particular, lpdoc can create and maintain fully automatically WWW and info sites containing on-line versions of the documents it produces. The lpdoc manual (and the Ciao system manuals) are generated by lpdoc. Lpdoc is distributed under the GNU general public license. Note: lpdoc is fully supported on Linux, Mac OS X, and other Un*x-like systems. Due to the use of several Un*x-related utilities, some documentation back-ends may require Cygwin under Win32. This documentation corresponds to version 3.0 (2011/7/7, 16:33:15 CEST).
Resumo:
This article presents research focused on tracking manual tasks that are applied in cognitive rehabilitation so as to analyze the movements of patients who suffer from Apraxia and Action Disorganization Syndrome (AADS). This kind of patients find executing Activities of Daily Living (ADL) too difficult due to the loss of memory and capacity to carry out sequential tasks or the impossibility of associating different objects with their functions. This contribution is developed from the work of Universidad Politcnica de Madrid and Technical University of Munich in collaboration with The University of Birmingham. The KinectTM for Windows device is used for this purpose. The data collected is compared to an ultrasonic motion capture system. The results indicate a moderate to strong correlation between signals. They also verify that KinectTM is very suitable and inexpensive. Moreover, it turns out to be a motion-capture system quite easy to implement for kinematics analysis in ADL.
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The aim of this work is to optimize a Monte Carlo (MC) kernel for electron radiation therapy (IOERT) compatible with intraoperative usage and to integrate it within an existing IOERT dedicated treatment planning system (TPS)
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Three different methods to reduce the noise power in the far-field pattern of an antenna when it is measured in a cylindrical near field system are presented and compared. The first one is based on a modal filtering while the other two are based on spatial filtering, either on an antenna plane or either on a cylinder of smaller radius. Simulated and measured results will be presented.
Resumo:
When the fresh fruit reaches the final markets from the suppliers, its quality is not always as good as it should, either because it has been mishandled during transportation or because it lacks an adequate quality control at the producer level, before being shipped. This is why it is necessary for the final markets to establish their own quality assessment system if they want to ensure to their customers the quality they want to sell. In this work, a system to control fruit quality at the last level of the distribution channel has been designed. The system combines rapid control techniques with laboratory equipment and statistical sampling protocols, to obtain a dynamic, objective process, which can substitute advantageously the quality control inspections carried out visually by human experts at the reception platform of most hypermarkets. Portable measuring equipment have been chosen (firmness tester, temperature and humidity sensors...) as well as easy-to-use laboratory equipment (texturometer, colorimeter, refractometer..,) combining them to control the most important fruit quality parameters (firmness, colour, sugars, acids). A complete computer network has been designed to control all the processes and store the collected data in real time, and to perform the computations. The sampling methods have been also defined to guarantee the confidence of the results. Some of the advantages of a quality assessment system as the proposed one are: the minimisation of human subjectivity, the ability to use modern measuring techniques, and the possibility of using it also as a supplier's quality control system. It can be also a way to clarify the quality limits of fruits among members of the commercial channel, as well as the first step in the standardisation of quality control procedures.
Resumo:
We recover and develop some robotic systems concepts (on the light of present systems tools) that were originated for an intended Mars Rover in the sixties of the last century at the Instrumentation Laboratory of MIT, where one of the authors was involved. The basic concepts came from the specifications for a type of generalized robot inspired in the structure of the vertebrate nervous systems, where the decision system was based in the structure and function of the Reticular Formation (RF). The vertebrate RF is supposed to commit the whole organism to one among various modes of behavior, so taking the decisions about the present overall task. That is, it is a kind of control and command system. In this concepts updating, the basic idea is that the RF comprises a set of computing units such that each computing module receives information only from a reduced part of the overall, little processed sensory inputs. Each computing unit is capable of both general diagnostics about overall input situations and of specialized diagnostics according to the values of a concrete subset of the input lines. Slave systems to this command and control computer, there are the sensors, the representations of external environment, structures for modeling and planning and finally, the effectors acting in the external world.
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En la actualidad se est viviendo el auge del Cloud Computing (Computacin en la Nube) y cada vez son ms las empresas importantes en el sector de las Tecnologas de la Informacin que apuestan con fuerza por estos servicios. Por un lado, algunas ofrecen servicios, como Amazon y su sistema IaaS (Infrastructure as a Service) Amazon Web Services (AWS); por otro, algunas los utilizan, como ocurre en el caso de este proyecto, en el que Telefonica I+D hace uso de los servicios proporcionados por AWS para sus proyectos. Debido a este crecimiento en el uso de las aplicaciones distribuidas es importante tener en cuenta el papel que desempean los desarrolladores y administradores de sistemas que han de trabajar y mantener todas las mquinas remotas de uno o varios proyectos desde una nica mquina local. El ayudar a realizar estas tareas de la forma ms cmoda y automtica posible es el objetivo principal de este proyecto. En concreto, el objetivo de este proyecto es el diseo y la implementacin de una solucin software que ayude a la productividad en el desarrollo y despliegue de aplicaciones en un conjunto de mquinas remotas desde una nica mquina local, teniendo como base una prueba de concepto realizada anteriormente que prueba las funcionalidades ms bsicas de las libreras utilizadas para el desarrollo de la herramienta. A lo largo de este proyecto se han estudiado las diferentes alternativas que se encuentran en el mercado que ofrecen al menos parte de la soluci6n a los problemas abordados, pese a que los requisitos de la empresa indicaban que la herramienta deba implementarse de forma completa. Se estudi a fondo despus la prueba de concepto de la que se parta para, con los conocimientos adquiridos sobre el tema, mejorarla cumpliendo los objetivos marcados. Tras el desarrollo y la implementaci6n completa de la herramienta se proponen posibles caminos a seguir en el futuro. ---ABSTRACT---Nowadays we are experiencing the rise of Cloud Computing and every day more and more important IT companies are betting hard for this kind of services. On one hand, some of these companies offer services such as Amazon IaaS (Infrastructure as a Service) system Amazon Web Services (AWS); on the other hand, some of them use these services, as in the case of this project, in which Telefonica I+D uses the services provided by AWS in their projects. Due this growth in the use of distributed applications it is important to consider the developers and system administrators' roles, who have to work and do the maintenance of all the remote machines from one or several projects from a single local machine. The main goal of this project is to help with these tasks making them as comfortable and automatically as possible. Specifically, the goal of this project is the design and implementation of a software solution that helps to achieve a better productivity in the development of applications on a set of remote machines from a single local machine, based on a proof of concept developed before, in which the basic functionality of the libraries used in this tool were tested. Throughout this project the different alternatives on the market that offer at least part of the solution to the problem addressed have been studied, although according to the requirements of the company, the tool should be implemented from scratch. After that, the basic proof of concept was thoroughly studied and improved with the knowledge acquired on the subject, fulfilling the marked goals. Once the development and full implementation of the tool is done, some ways of improvement for the future are suggested.
Resumo:
En el sector de la edificacin, las grandes constructoras comienzan a considerar aspectos medioambientales, no limitndose a lo establecido por la legislacin vigente, y buscando la implementacin de buenas prcticas. Si bien este hecho es una realidad para las grandes empresas constructoras, todava falta que la gran mayora de las empresas del sector (pequeas y medianas) adopten sta tendencia. En este sentido, las publicaciones y estadsticas consultadas revelan que el sector de la construccin sigue siendo el sector con menor nmero de Sistemas de Gestin Ambiental (SGA) certificados en comparacin con otros sectores industriales, debido principalmente a las peculiaridades de su actividad. Por otra parte, el sector de la construccin genera grandes cantidades de residuos de construccin y demolicin (RCD). Aunque, en los ltimos aos la actividad de la construccin ha disminuido, debido a la crisis econmica del pas, no hay que olvidar todos los problemas causados por este tipo de residuos, o mejor dicho, por su gestin. La gestin de los RCD actual est lejos de alcanzar la meta propuesta en la Directiva Marco de Residuos (DMR), la cual exige un objetivo global para el ao 2020 en el que el 70% de todos los RCD generados debern ser reciclados en los pases de la UE. Pero, la realidad es que slo el 50% de la RCD generados en la Unin Europea se recicla. Por este motivo, en los ltimos aos se ha producido una completa modificacin del rgimen jurdico aplicable a los RCD, incorporando importantes novedades a nuestro ordenamiento interno como son: la redaccin de un Estudio de gestin de RCD (en fase de diseo) y un Plan de gestin de RCD (en fase de ejecucin). Entre estas medidas destaca el poder conocer, con la antelacin suficiente, la cantidad y el momento en que los RCD son generados, para as poder planificar la gestin ms adecuada para cada categora de RCD. Es por ello que el desarrollo de cualquier instrumento que determine la estimacin de RCD as como iniciativas para su control debe ser considerado como una herramienta para dar respuestas reales en el campo de la sostenibilidad en la edificacin. Por todo lo anterior, el principal objetivo de la Tesis Doctoral es mejorar la gestin actual de los RCD, a travs de la elaboracin e implementacin en obra de un Sistema de gestin de RCD en fase de ejecucin que podr ser incluido en el Sistema de Gestin Ambiental de las empresas constructoras. Para ello, se ha identificado la actividad que ms residuo genera, as como las diferentes categoras de RCD generadas durante su ejecucin, a travs del anlisis de nueve obras de edificacin de nueva planta. Posteriormente, se han determinado y evaluado, en funcin de su eficacia y viabilidad, veinte buenas prcticas encaminadas a reducir la generacin de RCD. Tambin, se han identificado y evaluado, en funcin de su coste econmico, cinco alternativas de gestin para cada categora de RCD generada. Por ltimo, se ha desarrollado e implementado un Sistema de Gestin de RCD en una empresa de construccin real. En definitiva, el Sistema de Gestin de RCD propuesto contiene una herramienta de estimacin de RCD y tambin proporciona una relacin de buenas prcticas, segn su viabilidad y eficacia, sobre los aspectos ms significativos en cuanto a la gestin de RCD se refiere. El uso de este Sistema de gestin de RCD ayudar a los tcnicos de la construccin en el desarrollo de los documentos "Estudio de gestin de RCD " y "Plan de gestin de RCD " - requeridos por ley -. Adems, el Sistema promueve la gestin ambiental de la empresa, favoreciendo la cohesin del proceso constructivo, estableciendo responsabilidades en el mbito de RCD y proporcionando un mayor control sobre el proceso. En conclusin, la implementacin de un sistema de gestin de RCD en obra ayuda a conseguir una actividad de edificacin, cuyo principal objetivo sea la generacin de residuos cero. ABSTRACT Currently, in the building sector, the main construction companies are considering environmental issues, not being limited to the current legislation, and seeking the implementation of good practices. While this fact is a reality for large construction companies, still the vast majority of construction companies (small and medium enterprises) need to accept this trend. In this sense, official publications and statistics reveal that the construction sector remains with the lowest number of certified Environmental Management Systems (EMS) compared to other industrial sectors, mainly due to the peculiarities of its activity. Moreover, the construction industry in Spain generates large volumes of construction and demolition waste (CDW) achieving a low recycling rate compared to other European Union countries and to the target set for 2020. Despite the complete change in the legal regime for CDW in Spain, there are still several difficulties for their application at the construction works. Among these difficulties the following can be highlighted: onsite segregation, estimating CDW generation and managing different CDW categories. Despite these difficulties, the proper CDW management must be one of the main aspects considered by construction companies in the EMS. However, at present the EMS used in construction companies consider very superficially CDW management issues. Therefore, current EMS should go a step further and include not only procedures for managing CDW globally, but also specific procedures for each CDW category, taking into account best practices for prevention, minimization and proper CDW management in order to achieve building construction works with zero waste generation. The few scientific studies analysing EMS implementation in construction enterprises focus on studying the benefits and barriers of their implementation. Despite the drawbacks found, implementing an EMS would bring benefits such as improving the corporate image in relation to the environment, ensuring compliance with the law or reducing environmental risks. Also, the international scientific community has shown great interest in defining models to estimate in advance the CDW that will be generated during the building construction or rehabilitation works. These studies analyse the overall waste generation and its different CDW categories. However, despite the many studies found on CDW quantification, analysing its evolution throughout the construction activities is a factor that must be further studied and discussed in greater depth, as results would be of great significance when planning the CDW management. According to the scientific studies analysing the implementation of good environmental practices in construction sites, it seems that, in general, the CDW collection system is done in a decentralized manner by each subcontracted company. In addition, the corporate image generated when poor practices are done may adversely affect the company's reputation and can result in loss of contracts. Finally, although there are numerous guides and manuals of good practices for CDW management, no references have been found implementing these measures in the Environmental Management System of the construction companies. From all the above, this thesis aims to provide answers to reduce the environmental impact caused by CDW generation in building construction works, in order to get a building process with zero waste generation. In this sense, is essential to generate new knowledge in order to implement a system which can carry out comprehensive management of CDW generated onsite, at the design stage until the end of its life cycle, taking into account both technical and economic criteria. Therefore, the main objective of this thesis is to define and implement a CDW management system for residential building construction works, helping construction agents not only to manage the CDW in accordance with current legislation, but also minimizing their generation on site by applying best practices, resulting in achieving the goal of zero waste in building works.
Resumo:
El presente Trabajo fin Fin de Mster, versa sobre una caracterizacin preliminar del comportamiento de un robot de tipo industrial, configurado por 4 eslabones y 4 grados de libertad, y sometido a fuerzas de mecanizado en su extremo. El entorno de trabajo planteado es el de plantas de fabricacin de piezas de aleaciones de aluminio para automocin. Este tipo de componentes parte de un primer proceso de fundicin que saca la pieza en bruto. Para series medias y altas, en funcin de las propiedades mecnicas y plsticas requeridas y los costes de produccin, la inyeccin a alta presin (HPDC) y la fundicin a baja presin (LPC) son las dos tecnologas ms usadas en esta primera fase. Para inyeccin a alta presin, las aleaciones de aluminio ms empleadas son, en designacin simblica segn norma EN 1706 (entre parntesis su designacin numrica); EN AC AlSi9Cu3(Fe) (EN AC 46000) , EN AC AlSi9Cu3(Fe)(Zn) (EN AC 46500), y EN AC AlSi12Cu1(Fe) (EN AC 47100). Para baja presin, EN AC AlSi7Mg0,3 (EN AC 42100). En los 3 primeros casos, los lmites de Silicio permitidos pueden superan el 10%. En el cuarto caso, es inferior al 10% por lo que, a los efectos de ser sometidas a mecanizados, las piezas fabricadas en aleaciones con Si superior al 10%, se puede considerar que son equivalentes, diferencindolas de la cuarta. Las tolerancias geomtricas y dimensionales conseguibles directamente de fundicin, recogidas en normas como ISO 8062 o DIN 1688-1, establecen lmites para este proceso. Fuera de esos lmites, las garantas en conseguir producciones con los objetivos de ppms aceptados en la actualidad por el mercado, obligan a ir a fases posteriores de mecanizado. Aquellas geometras que, funcionalmente, necesitan disponer de unas tolerancias geomtricas y/o dimensionales definidas acorde a ISO 1101, y no capaces por este proceso inicial de moldeado a presin, deben ser procesadas en una fase posterior en clulas de mecanizado. En este caso, las tolerancias alcanzables para procesos de arranque de viruta se recogen en normas como ISO 2768. Las clulas de mecanizado se componen, por lo general, de varios centros de control numrico interrelacionados y comunicados entre s por robots que manipulan las piezas en proceso de uno a otro. Dichos robots, disponen en su extremo de una pinza utillada para poder coger y soltar las piezas en los tiles de mecanizado, las mesas de intercambio para cambiar la pieza de posicin o en utillajes de equipos de medicin y prueba, o en cintas de entrada o salida. La repetibilidad es alta, de centsimas incluso, definida segn norma ISO 9283. El problema es que, estos rangos de repetibilidad slo se garantizan si no se hacen esfuerzos o stos son despreciables (caso de mover piezas). Aunque las inercias de mover piezas a altas velocidades hacen que la trayectoria intermedia tenga poca precisin, al inicio y al final (al coger y dejar pieza, p.e.) se hacen a velocidades relativamente bajas que hacen que el efecto de las fuerzas de inercia sean menores y que permiten garantizar la repetibilidad anteriormente indicada. No ocurre as si se quitara la garra y se intercambia con un cabezal motorizado con una herramienta como broca, mandrino, plato de cuchillas, fresas frontales o tangenciales Las fuerzas ejercidas de mecanizado generaran unos pares en las uniones tan grandes y tan variables que el control del robot no sera capaz de responder (o no est preparado, en un principio) y generara una desviacin en la trayectoria, realizada a baja velocidad, que desencadenara en un error de posicin (ver norma ISO 5458) no asumible para la funcionalidad deseada. Se podra llegar al caso de que la tolerancia alcanzada por un pretendido proceso ms exacto diera una dimensin peor que la que dara el proceso de fundicin, en principio con mayor variabilidad dimensional en proceso (y por ende con mayor intervalo de tolerancia garantizable). De hecho, en los CNCs, la precisin es muy elevada, (pudindose despreciar en la mayora de los casos) y no es la responsable de, por ejemplo la tolerancia de posicin al taladrar un agujero. Factores como, temperatura de la sala y de la pieza, calidad constructiva de los utillajes y rigidez en el amarre, error en el giro de mesas y de colocacin de pieza, si lleva agujeros previos o no, si la herramienta est bien equilibrada y el cono es el adecuado para el tipo de mecanizado influyen ms. Es interesante que, un elemento no especfico tan comn en una planta industrial, en el entorno anteriormente descrito, como es un robot, el cual no sera necesario aadir por disponer de l ya (y por lo tanto la inversin sera muy pequea), puede mejorar la cadena de valor disminuyendo el costo de fabricacin. Y si se pudiera conjugar que ese robot destinado a tareas de manipulacin, en los muchos tiempos de espera que va a disfrutar mientras el CNC arranca viruta, pudiese coger un cabezal y apoyar ese mecanizado; sera doblemente interesante. Por lo tanto, se antoja sugestivo poder conocer su comportamiento e intentar explicar qu sera necesario para llevar esto a cabo, motivo de este trabajo. La arquitectura de robot seleccionada es de tipo SCARA. La bsqueda de un robot cmodo de modelar y de analizar cinemtica y dinmicamente, sin limitaciones relevantes en la multifuncionalidad de trabajos solicitados, ha llevado a esta eleccin, frente a otras arquitecturas como por ejemplo los robots antropomrficos de 6 grados de libertad, muy populares a nivel industrial. Este robot dispone de 3 uniones, de las cuales 2 son de tipo par de revolucin (1 grado de libertad cada una) y la tercera es de tipo corredera o par cilndrico (2 grados de libertad). La primera unin, de tipo par de revolucin, sirve para unir el suelo (considerado como eslabn nmero 1) con el eslabn nmero 2. La segunda unin, tambin de ese tipo, une el eslabn nmero 2 con el eslabn nmero 3. Estos 2 brazos, pueden describir un movimiento horizontal, en el plano X-Y. El tercer eslabn, est unido al eslabn nmero 4 por la unin de tipo corredera. El movimiento que puede describir es paralelo al eje Z. El robot es de 4 grados de libertad (4 motores). En relacin a los posibles trabajos que puede realizar este tipo de robot, su versatilidad abarca tanto operaciones tpicas de manipulacin como operaciones de arranque de viruta. Uno de los mecanizados ms usuales es el taladrado, por lo cual se elige ste para su modelizacin y anlisis. Dentro del taladrado se elegir para acotar las fuerzas, taladrado en macizo con broca de dimetro 9 mm. El robot se ha considerado por el momento que tenga comportamiento de slido rgido, por ser el mayor efecto esperado el de los pares en las uniones. Para modelar el robot se utiliza el mtodo de los sistemas multicuerpos. Dentro de este mtodo existen diversos tipos de formulaciones (p.e. Denavit-Hartenberg). D-H genera una cantidad muy grande de ecuaciones e incgnitas. Esas incgnitas son de difcil comprensin y, para cada posicin, hay que detenerse a pensar qu significado tienen. Se ha optado por la formulacin de coordenadas naturales. Este sistema utiliza puntos y vectores unitarios para definir la posicin de los distintos cuerpos, y permite compartir, cuando es posible y se quiere, para definir los pares cinemticos y reducir al mismo tiempo el nmero de variables. Las incgnitas son intuitivas, las ecuaciones de restriccin muy sencillas y se reduce considerablemente el nmero de ecuaciones e incgnitas. Sin embargo, las coordenadas naturales puras tienen 2 problemas. El primero, que 2 elementos con un ngulo de 0 o 180 grados, dan lugar a puntos singulares que pueden crear problemas en las ecuaciones de restriccin y por lo tanto han de evitarse. El segundo, que tampoco inciden directamente sobre la definicin o el origen de los movimientos. Por lo tanto, es muy conveniente complementar esta formulacin con ngulos y distancias (coordenadas relativas). Esto da lugar a las coordenadas naturales mixtas, que es la formulacin final elegida para este TFM. Las coordenadas naturales mixtas no tienen el problema de los puntos singulares. Y la ventaja ms importante reside en su utilidad a la hora de aplicar fuerzas motrices, momentos o evaluar errores. Al incidir sobre la incgnita origen (ngulos o distancias) controla los motores de manera directa. El algoritmo, la simulacin y la obtencin de resultados se ha programado mediante Matlab. Para realizar el modelo en coordenadas naturales mixtas, es preciso modelar en 2 pasos el robot a estudio. El primer modelo se basa en coordenadas naturales. Para su validacin, se plantea una trayectoria definida y se analiza cinemticamente si el robot satisface el movimiento solicitado, manteniendo su integridad como sistema multicuerpo. Se cuantifican los puntos (en este caso inicial y final) que configuran el robot. Al tratarse de slidos rgidos, cada eslabn queda definido por sus respectivos puntos inicial y final (que son los ms interesantes para la cinemtica y la dinmica) y por un vector unitario no colineal a esos 2 puntos. Los vectores unitarios se colocan en los lugares en los que se tenga un eje de rotacin o cuando se desee obtener informacin de un ngulo. No son necesarios vectores unitarios para medir distancias. Tampoco tienen por qu coincidir los grados de libertad con el nmero de vectores unitarios. Las longitudes de cada eslabn quedan definidas como constantes geomtricas. Se establecen las restricciones que definen la naturaleza del robot y las relaciones entre los diferentes elementos y su entorno. La trayectoria se genera por una nube de puntos continua, definidos en coordenadas independientes. Cada conjunto de coordenadas independientes define, en un instante concreto, una posicin y postura de robot determinada. Para conocerla, es necesario saber qu coordenadas dependientes hay en ese instante, y se obtienen resolviendo por el mtodo de Newton-Rhapson las ecuaciones de restriccin en funcin de las coordenadas independientes. El motivo de hacerlo as es porque las coordenadas dependientes deben satisfacer las restricciones, cosa que no ocurre con las coordenadas independientes. Cuando la validez del modelo se ha probado (primera validacin), se pasa al modelo 2. El modelo nmero 2, incorpora a las coordenadas naturales del modelo nmero 1, las coordenadas relativas en forma de ngulos en los pares de revolucin (3 ngulos; 1, 2 y 3) y distancias en los pares prismticos (1 distancia; s). Estas coordenadas relativas pasan a ser las nuevas coordenadas independientes (sustituyendo a las coordenadas independientes cartesianas del modelo primero, que eran coordenadas naturales). Es necesario revisar si el sistema de vectores unitarios del modelo 1 es suficiente o no. Para este caso concreto, se han necesitado aadir 1 vector unitario adicional con objeto de que los ngulos queden perfectamente determinados con las correspondientes ecuaciones de producto escalar y/o vectorial. Las restricciones habrn de ser incrementadas en, al menos, 4 ecuaciones; una por cada nueva incgnita. La validacin del modelo nmero 2, tiene 2 fases. La primera, al igual que se hizo en el modelo nmero 1, a travs del anlisis cinemtico del comportamiento con una trayectoria definida. Podran obtenerse del modelo 2 en este anlisis, velocidades y aceleraciones, pero no son necesarios. Tan slo interesan los movimientos o desplazamientos finitos. Comprobada la coherencia de movimientos (segunda validacin), se pasa a analizar cinemticamente el comportamiento con trayectorias interpoladas. El anlisis cinemtico con trayectorias interpoladas, trabaja con un nmero mnimo de 3 puntos mster. En este caso se han elegido 3; punto inicial, punto intermedio y punto final. El nmero de interpolaciones con el que se acta es de 50 interpolaciones en cada tramo (cada 2 puntos mster hay un tramo), resultando un total de 100 interpolaciones. El mtodo de interpolacin utilizado es el de splines cbicas con condicin de aceleracin inicial y final constantes, que genera las coordenadas independientes de los puntos interpolados de cada tramo. Las coordenadas dependientes se obtienen resolviendo las ecuaciones de restriccin no lineales con el mtodo de Newton-Rhapson. El mtodo de las splines cbicas es muy continuo, por lo que si se desea modelar una trayectoria en el que haya al menos 2 movimientos claramente diferenciados, es preciso hacerlo en 2 tramos y unirlos posteriormente. Sera el caso en el que alguno de los motores se desee expresamente que est parado durante el primer movimiento y otro distinto lo est durante el segundo movimiento (y as sucesivamente). Obtenido el movimiento, se calculan, tambin mediante frmulas de diferenciacin numrica, las velocidades y aceleraciones independientes. El proceso es anlogo al anteriormente explicado, recordando la condicin impuesta de que la aceleracin en el instante t= 0 y en instante t= final, se ha tomado como 0. Las velocidades y aceleraciones dependientes se calculan resolviendo las correspondientes derivadas de las ecuaciones de restriccin. Se comprueba, de nuevo, en una tercera validacin del modelo, la coherencia del movimiento interpolado. La dinmica inversa calcula, para un movimiento definido -conocidas la posicin, velocidad y la aceleracin en cada instante de tiempo-, y conocidas las fuerzas externas que actan (por ejemplo el peso); qu fuerzas hay que aplicar en los motores (donde hay control) para que se obtenga el citado movimiento. En la dinmica inversa, cada instante del tiempo es independiente de los dems y tiene una posicin, una velocidad y una aceleracin y unas fuerzas conocidas. En este caso concreto, se desean aplicar, de momento, slo las fuerzas debidas al peso, aunque se podran haber incorporado fuerzas de otra naturaleza si se hubiese deseado. Las posiciones, velocidades y aceleraciones, proceden del clculo cinemtico. El efecto inercial de las fuerzas tenidas en cuenta (el peso) es calculado. Como resultado final del anlisis dinmico inverso, se obtienen los pares que han de ejercer los cuatro motores para replicar el movimiento prescrito con las fuerzas que estaban actuando. La cuarta validacin del modelo consiste en confirmar que el movimiento obtenido por aplicar los pares obtenidos en la dinmica inversa, coinciden con el obtenido en el anlisis cinemtico (movimiento terico). Para ello, es necesario acudir a la dinmica directa. La dinmica directa se encarga de calcular el movimiento del robot, resultante de aplicar unos pares en motores y unas fuerzas en el robot. Por lo tanto, el movimiento real resultante, al no haber cambiado ninguna condicin de las obtenidas en la dinmica inversa (pares de motor y fuerzas inerciales debidas al peso de los eslabones) ha de ser el mismo al movimiento terico. Siendo as, se considera que el robot est listo para trabajar. Si se introduce una fuerza exterior de mecanizado no contemplada en la dinmica inversa y se asigna en los motores los mismos pares resultantes de la resolucin del problema dinmico inverso, el movimiento real obtenido no es igual al movimiento terico. El control de lazo cerrado se basa en ir comparando el movimiento real con el deseado e introducir las correcciones necesarias para minimizar o anular las diferencias. Se aplican ganancias en forma de correcciones en posicin y/o velocidad para eliminar esas diferencias. Se evala el error de posicin como la diferencia, en cada punto, entre el movimiento terico deseado en el anlisis cinemtico y el movimiento real obtenido para cada fuerza de mecanizado y una ganancia concreta. Finalmente, se mapea el error de posicin obtenido para cada fuerza de mecanizado y las diferentes ganancias previstas, graficando la mejor precisin que puede dar el robot para cada operacin que se le requiere, y en qu condiciones. -------------- This Masters Thesis deals with a preliminary characterization of the behaviour for an industrial robot, configured with 4 elements and 4 degrees of freedoms, and subjected to machining forces at its end. Proposed working conditions are those typical from manufacturing plants with aluminium alloys for automotive industry. This type of components comes from a first casting process that produces rough parts. For medium and high volumes, high pressure die casting (HPDC) and low pressure die casting (LPC) are the most used technologies in this first phase. For high pressure die casting processes, most used aluminium alloys are, in simbolic designation according EN 1706 standard (between brackets, its numerical designation); EN AC AlSi9Cu3(Fe) (EN AC 46000) , EN AC AlSi9Cu3(Fe)(Zn) (EN AC 46500), y EN AC AlSi12Cu1(Fe) (EN AC 47100). For low pressure, EN AC AlSi7Mg0,3 (EN AC 42100). For the 3 first alloys, Si allowed limits can exceed 10% content. Fourth alloy has admisible limits under 10% Si. That means, from the point of view of machining, that components made of alloys with Si content above 10% can be considered as equivalent, and the fourth one must be studied separately. Geometrical and dimensional tolerances directly achievables from casting, gathered in standards such as ISO 8062 or DIN 1688-1, establish a limit for this process. Out from those limits, guarantees to achieve batches with objetive ppms currently accepted by market, force to go to subsequent machining process. Those geometries that functionally require a geometrical and/or dimensional tolerance defined according ISO 1101, not capable with initial moulding process, must be obtained afterwards in a machining phase with machining cells. In this case, tolerances achievables with cutting processes are gathered in standards such as ISO 2768. In general terms, machining cells contain several CNCs that they are interrelated and connected by robots that handle parts in process among them. Those robots have at their end a gripper in order to take/remove parts in machining fixtures, in interchange tables to modify position of part, in measurement and control tooling devices, or in entrance/exit conveyors. Repeatibility for robot is tight, even few hundredths of mm, defined according ISO 9283. Problem is like this; those repeatibilty ranks are only guaranteed when there are no stresses or they are not significant (f.e. due to only movement of parts). Although inertias due to moving parts at a high speed make that intermediate paths have little accuracy, at the beginning and at the end of trajectories (f.e, when picking part or leaving it) movement is made with very slow speeds that make lower the effect of inertias forces and allow to achieve repeatibility before mentioned. It does not happens the same if gripper is removed and it is exchanged by an spindle with a machining tool such as a drilling tool, a pcd boring tool, a face or a tangential milling cutter Forces due to machining would create such big and variable torques in joints that control from the robot would not be able to react (or it is not prepared in principle) and would produce a deviation in working trajectory, made at a low speed, that would trigger a position error (see ISO 5458 standard) not assumable for requested function. Then it could be possible that tolerance achieved by a more exact expected process would turn out into a worst dimension than the one that could be achieved with casting process, in principle with a larger dimensional variability in process (and hence with a larger tolerance range reachable). As a matter of fact, accuracy is very tight in CNC, (its influence can be ignored in most cases) and it is not the responsible of, for example position tolerance when drilling a hole. Factors as, room and part temperature, manufacturing quality of machining fixtures, stiffness at clamping system, rotating error in 4th axis and part positioning error, if there are previous holes, if machining tool is properly balanced, if shank is suitable for that machining type have more influence. It is interesting to know that, a non specific element as common, at a manufacturing plant in the enviroment above described, as a robot (not needed to be added, therefore with an additional minimum investment), can improve value chain decreasing manufacturing costs. And when it would be possible to combine that the robot dedicated to handling works could support CNCs works in its many waiting time while CNCs cut, and could take an spindle and help to cut; it would be double interesting. So according to all this, it would be interesting to be able to know its behaviour and try to explain what would be necessary to make this possible, reason of this work. Selected robot architecture is SCARA type. The search for a robot easy to be modeled and kinematically and dinamically analyzed, without significant limits in the multifunctionality of requested operations, has lead to this choice. Due to that, other very popular architectures in the industry, f.e. 6 DOFs anthropomorphic robots, have been discarded. This robot has 3 joints, 2 of them are revolute joints (1 DOF each one) and the third one is a cylindrical joint (2 DOFs). The first joint, a revolute one, is used to join floor (body 1) with body 2. The second one, a revolute joint too, joins body 2 with body 3. These 2 bodies can move horizontally in X-Y plane. Body 3 is linked to body 4 with a cylindrical joint. Movement that can be made is paralell to Z axis. The robt has 4 degrees of freedom (4 motors). Regarding potential works that this type of robot can make, its versatility covers either typical handling operations or cutting operations. One of the most common machinings is to drill. That is the reason why it has been chosen for the model and analysis. Within drilling, in order to enclose spectrum force, a typical solid drilling with 9 mm diameter. The robot is considered, at the moment, to have a behaviour as rigid body, as biggest expected influence is the one due to torques at joints. In order to modelize robot, it is used multibodies system method. There are under this heading different sorts of formulations (f.e. Denavit-Hartenberg). D-H creates a great amount of equations and unknown quantities. Those unknown quatities are of a difficult understanding and, for each position, one must stop to think about which meaning they have. The choice made is therefore one of formulation in natural coordinates. This system uses points and unit vectors to define position of each different elements, and allow to share, when it is possible and wished, to define kinematic torques and reduce number of variables at the same time. Unknown quantities are intuitive, constrain equations are easy and number of equations and variables are strongly reduced. However, pure natural coordinates suffer 2 problems. The first one is that 2 elements with an angle of 0 or 180, give rise to singular positions that can create problems in constrain equations and therefore they must be avoided. The second problem is that they do not work directly over the definition or the origin of movements. Given that, it is highly recommended to complement this formulation with angles and distances (relative coordinates). This leads to mixed natural coordinates, and they are the final formulation chosen for this MTh. Mixed natural coordinates have not the problem of singular positions. And the most important advantage lies in their usefulness when applying driving forces, torques or evaluating errors. As they influence directly over origin variable (angles or distances), they control motors directly. The algorithm, simulation and obtaining of results has been programmed with Matlab. To design the model in mixed natural coordinates, it is necessary to model the robot to be studied in 2 steps. The first model is based in natural coordinates. To validate it, it is raised a defined trajectory and it is kinematically analyzed if robot fulfils requested movement, keeping its integrity as multibody system. The points (in this case starting and ending points) that configure the robot are quantified. As the elements are considered as rigid bodies, each of them is defined by its respectively starting and ending point (those points are the most interesting ones from the point of view of kinematics and dynamics) and by a non-colinear unit vector to those points. Unit vectors are placed where there is a rotating axis or when it is needed information of an angle. Unit vectors are not needed to measure distances. Neither DOFs must coincide with the number of unit vectors. Lengths of each arm are defined as geometrical constants. The constrains that define the nature of the robot and relationships among different elements and its enviroment are set. Path is generated by a cloud of continuous points, defined in independent coordinates. Each group of independent coordinates define, in an specific instant, a defined position and posture for the robot. In order to know it, it is needed to know which dependent coordinates there are in that instant, and they are obtained solving the constraint equations with Newton-Rhapson method according to independent coordinates. The reason to make it like this is because dependent coordinates must meet constraints, and this is not the case with independent coordinates. When suitability of model is checked (first approval), it is given next step to model 2. Model 2 adds to natural coordinates from model 1, the relative coordinates in the shape of angles in revoluting torques (3 angles; 1, 2 and 3) and distances in prismatic torques (1 distance; s). These relative coordinates become the new independent coordinates (replacing to cartesian independent coordinates from model 1, that they were natural coordinates). It is needed to review if unit vector system from model 1 is enough or not . For this specific case, it was necessary to add 1 additional unit vector to define perfectly angles with their related equations of dot and/or cross product. Constrains must be increased in, at least, 4 equations; one per each new variable. The approval of model 2 has two phases. The first one, same as made with model 1, through kinematic analysis of behaviour with a defined path. During this analysis, it could be obtained from model 2, velocities and accelerations, but they are not needed. They are only interesting movements and finite displacements. Once that the consistence of movements has been checked (second approval), it comes when the behaviour with interpolated trajectories must be kinematically analyzed. Kinematic analysis with interpolated trajectories work with a minimum number of 3 master points. In this case, 3 points have been chosen; starting point, middle point and ending point. The number of interpolations has been of 50 ones in each strecht (each 2 master points there is an strecht), turning into a total of 100 interpolations. The interpolation method used is the cubic splines one with condition of constant acceleration both at the starting and at the ending point. This method creates the independent coordinates of interpolated points of each strecht. The dependent coordinates are achieved solving the non-linear constrain equations with Newton-Rhapson method. The method of cubic splines is very continuous, therefore when it is needed to design a trajectory in which there are at least 2 movements clearly differents, it is required to make it in 2 steps and join them later. That would be the case when any of the motors would keep stopped during the first movement, and another different motor would remain stopped during the second movement (and so on). Once that movement is obtained, they are calculated, also with numerical differenciation formulas, the independent velocities and accelerations. This process is analogous to the one before explained, reminding condition that acceleration when t=0 and t=end are 0. Dependent velocities and accelerations are calculated solving related derivatives of constrain equations. In a third approval of the model it is checked, again, consistence of interpolated movement. Inverse dynamics calculates, for a defined movement knowing position, velocity and acceleration in each instant of time-, and knowing external forces that act (f.e. weights); which forces must be applied in motors (where there is control) in order to obtain requested movement. In inverse dynamics, each instant of time is independent of the others and it has a position, a velocity, an acceleration and known forces. In this specific case, it is intended to apply, at the moment, only forces due to the weight, though forces of another nature could have been added if it would have been preferred. The positions, velocities and accelerations, come from kinematic calculation. The inertial effect of forces taken into account (weight) is calculated. As final result of the inverse dynamic analysis, the are obtained torques that the 4 motors must apply to repeat requested movement with the forces that were acting. The fourth approval of the model consists on confirming that the achieved movement due to the use of the torques obtained in the inverse dynamics, are in accordance with movements from kinematic analysis (theoretical movement). For this, it is necessary to work with direct dynamics. Direct dynamic is in charge of calculating the movements of robot that results from applying torques at motors and forces at the robot. Therefore, the resultant real movement, as there was no change in any condition of the ones obtained at the inverse dynamics (motor torques and inertial forces due to weight of elements) must be the same than theoretical movement. When these results are achieved, it is considered that robot is ready to work. When a machining external force is introduced and it was not taken into account before during the inverse dynamics, and torques at motors considered are the ones of the inverse dynamics, the real movement obtained is not the same than the theoretical movement. Closed loop control is based on comparing real movement with expected movement and introducing required corrrections to minimize or cancel differences. They are applied gains in the way of corrections for position and/or tolerance to remove those differences. Position error is evaluated as the difference, in each point, between theoretical movemment (calculated in the kinematic analysis) and the real movement achieved for each machining force and for an specific gain. Finally, the position error obtained for each machining force and gains are mapped, giving a chart with the best accuracy that the robot can give for each operation that has been requested and which conditions must be provided.
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The well-known eponym El Sidrn has a very special history. It started with the development of a karstic system between two types of rock (sandstone and Neogene conglomerates) as a result of the flow of a small stream. It continued with the use of the cave as a refuge and a hiding place during the Spanish Civil War and the aftermath and with the presence of some endemic species of bats and cave insects
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With the ever growing trend of smart phones and tablets, Android is becoming more and more popular everyday. With more than one billion active users i to date, Android is the leading technology in smart phone arena. In addition to that, Android also runs on Android TV, Android smart watches and cars. Therefore, in recent years, Android applications have become one of the major development sectors in software industry. As of mid 2013, the number of published applications on Google Play had exceeded one million and the cumulative number of downloads was more than 50 billionii. A 2013 survey also revealed that 71% of the mobile application developers work on developing Android applicationsiii. Considering this size of Android applications, it is quite evident that people rely on these applications on a daily basis for the completion of simple tasks like keeping track of weather to rather complex tasks like managing ones bank accounts. Hence, like every other kind of code, Android code also needs to be verified in order to work properly and achieve a certain confidence level. Because of the gigantic size of the number of applications, it becomes really hard to manually test Android applications specially when it has to be verified for various versions of the OS and also, various device configurations such as different screen sizes and different hardware availability. Hence, recently there has been a lot of work on developing different testing methods for Android applications in Computer Science fraternity. The model of Android attracts researchers because of its open source nature. It makes the whole research model more streamlined when the code for both, application and the platform are readily available to analyze. And hence, there has been a great deal of research in testing and static analysis of Android applications. A great deal of this research has been focused on the input test generation for Android applications. Hence, there are a several testing tools available now, which focus on automatic generation of test cases for Android applications. These tools differ with one another on the basis of their strategies and heuristics used for this generation of test cases. But there is still very little work done on the comparison of these testing tools and the strategies they use. Recently, some research work has been carried outiv in this regard that compared the performance of various available tools with respect to their respective code coverage, fault detection, ability to work on multiple platforms and their ease of use. It was done, by running these tools on a total of 60 real world Android applications. The results of this research showed that although effective, these strategies being used by the tools, also face limitations and hence, have room for improvement. The purpose of this thesis is to extend this research into a more specific and attribute- oriented way. Attributes refer to the tasks that can be completed using the Android platform. It can be anything ranging from a basic system call for receiving an SMS to more complex tasks like sending the user to another application from the current one. The idea is to develop a benchmark for Android testing tools, which is based on the performance related to these attributes. This will allow the comparison of these tools with respect to these attributes. For example, if there is an application that plays some audio file, will the testing tool be able to generate a test input that will warrant the execution of this audio file? Using multiple applications using different attributes, it can be visualized that which testing tool is more useful for which kinds of attributes. In this thesis, it was decided that 9 attributes covering the basic nature of tasks, will be targeted for the assessment of three testing tools. Later this can be done for much more attributes to compare even more testing tools. The aim of this work is to show that this approach is effective and can be used on a much larger scale. One of the flagship features of this work, which also differentiates it with the previous work, is that the applications used, are all specially made for this research. The reason for doing that is to analyze just that specific attribute in isolation, which the application is focused on, and not allow the tool to get bottlenecked by something trivial, which is not the main attribute under testing. This means 9 applications, each focused on one specific attribute. The main contributions of this thesis are: A summary of the three existing testing tools and their respective techniques for automatic test input generation of Android Applications. A detailed study of the usage of these testing tools using the 9 applications specially designed and developed for this study. The analysis of the obtained results of the study carried out. And a comparison of the performance of the selected tools.