31 resultados para Flexible manufacturing system
Resumo:
Kinetic Monte Carlo (KMC) is a widely used technique to simulate the evolution of radiation damage inside solids. Despite de fact that this technique was developed several decades ago, there is not an established and easy to access simulating tool for researchers interested in this field, unlike in the case of molecular dynamics or density functional theory calculations. In fact, scientists must develop their own tools or use unmaintained ones in order to perform these types of simulations. To fulfil this need, we have developed MMonCa, the Modular Monte Carlo simulator. MMonCa has been developed using professional C++ programming techniques and has been built on top of an interpreted language to allow having a powerful yet flexible, robust but customizable and easy to access modern simulator. Both non lattice and Lattice KMC modules have been developed. We will present in this conference, for the first time, the MMonCa simulator. Along with other (more detailed) contributions in this meeting, the versatility of MMonCa to study a number of problems in different materials (particularly, Fe and W) subject to a wide range of conditions will be shown. Regarding KMC simulations, we have studied neutron-generated cascade evolution in Fe (as a model material). Starting with a Frenkel pair distribution we have followed the defect evolution up to 450 K. Comparison with previous simulations and experiments shows excellent agreement. Furthermore, we have studied a more complex system (He-irradiated W:C) using a previous parametrization [1]. He-irradiation at 4 K followed by isochronal annealing steps up to 500 K has been simulated with MMonCa. The He energy was 400 eV or 3 keV. In the first case, no damage is associated to the He implantation, whereas in the second one, a significant Frenkel pair concentration (evolving into complex clusters) is associated to the He ions. We have been able to explain He desorption both in the absence and in the presence of Frenkel pairs and we have also applied MMonCa to high He doses and fluxes at elevated temperatures. He migration and trapping dominate the kinetics of He desorption. These processes will be discussed and compared to experimental results. [1] C.S. Becquart et al. J. Nucl. Mater. 403 (2010) 75
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This paper describes the experiences using remote laboratories for thorough analysis of a thermal system, including disturbances. Remote laboratories for education in subjects of control, is a common resorted method, used by universities. This method is applied to offer a flexible service in schedules so as to obtain greater and better results of available resources. Remote laboratories have been used for controlling physical devices remotely. Furthermore, remote labs have been used for transfer function identification of real equipment. Nevertheless, remote analyses of disturbances have not been done. The aim of this contribution is thereby to apply the experience of remote laboratories in the study of disturbances. Some experiments are carried out to demonstrate the effectiveness in using remote laboratories for complete analysis of a thermal system. Considering the remote access to thermal system, “Sistema de Laboratorios a Distancia” (SLD) was used.
Resumo:
In this paper we propose a flexible Multi-Agent Architecture together with a methodology for indoor location which allows us to locate any mobile station (MS) such as a Laptop, Smartphone, Tablet or a robotic system in an indoor environment using wireless technology. Our technology is complementary to the GPS location finder as it allows us to locate a mobile system in a specific room on a specific floor using the Wi-Fi networks. The idea is that any MS will have an agent known at a Fuzzy Location Software Agent (FLSA) with a minimum capacity processing at its disposal which collects the power received at different Access Points distributed around the floor and establish its location on a plan of the floor of the building. In order to do so it will have to communicate with the Fuzzy Location Manager Software Agent (FLMSA). The FLMSAs are local agents that form part of the management infrastructure of the Wi-Fi network of the Organization. The FLMSA implements a location estimation methodology divided into three phases (measurement, calibration and estimation) for locating mobile stations (MS). Our solution is a fingerprint-based positioning system that overcomes the problem of the relative effect of doors and walls on signal strength and is independent of the network device manufacturer. In the measurement phase, our system collects received signal strength indicator (RSSI) measurements from multiple access points. In the calibration phase, our system uses these measurements in a normalization process to create a radio map, a database of RSS patterns. Unlike traditional radio map-based methods, our methodology normalizes RSS measurements collected at different locations on a floor. In the third phase, we use Fuzzy Controllers to locate an MS on the plan of the floor of a building. Experimental results demonstrate the accuracy of the proposed method. From these results it is clear that the system is highly likely to be able to locate an MS in a room or adjacent room.
Resumo:
One of the most important design constraints of a climbing robot is its own weight. When links or legs are used as a locomotion system they tend to be composed of special lightweight materials, or four-bars-linkage mechanisms are designed to reduce the weight with small rigidity looses. In these cases, flexibility appears and undesirable effects, such as dynamics vibrations, must be avoided at least when the robot moves at low speeds. The knowledge of the real tip position requires the computation of its compliance or stiffness matrix and the external forces applied to the structure. Gravitational forces can be estimated, but external tip forces need to be measured. This paper proposes a strain gauge system which achieves the following tasks: (i) measurement of the external tip forces, and (ii) estimation of the real tip position (including flexibility effects). The main advantages of the proposed system are: (a) the use of external force sensors is avoided, and (b) a substantial reduction of the robot weight is achieved in comparison with other external force measurement systems. The proposed method is applied to a real symmetric climbing robot and experimental results are presented.
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In this paper, an architecture based on a scalable and flexible set of Evolvable Processing arrays is presented. FPGA-native Dynamic Partial Reconfiguration (DPR) is used for evolution, which is done intrinsically, letting the system to adapt autonomously to variable run-time conditions, including the presence of transient and permanent faults. The architecture supports different modes of operation, namely: independent, parallel, cascaded or bypass mode. These modes of operation can be used during evolution time or during normal operation. The evolvability of the architecture is combined with fault-tolerance techniques, to enhance the platform with self-healing features, making it suitable for applications which require both high adaptability and reliability. Experimental results show that such a system may benefit from accelerated evolution times, increased performance and improved dependability, mainly by increasing fault tolerance for transient and permanent faults, as well as providing some fault identification possibilities. The evolvable HW array shown is tailored for window-based image processing applications.
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We demonstrate the capability of a laser micromachining workstation for cost-effective manufacturing of a variety of microfluidic devices, including SU-8 microchannels on silicon wafers and 3D complex structures made on polyimide Kapton® or poly carbonate (PC). The workstation combines a KrF excimer laser at 248 nm and a Nd3+:YVO4 DPSS with a frequency tripled at 355 nm with a lens magnification 10X, both lasers working at a pulsed regime with nanoseconds (ns) pulse duration. Workstation also includes a high-resolution motorized XYZ-tilt axis (~ 1 um / axis) and a Through The Lens (TTL) imaging system for a high accurate positioning over a 120 x 120 mm working area. We have surveyed different fabrication techniques: direct writing lithography,mask manufacturing for contact lithography and polymer laser ablation for complex 3D devices, achieving width channels down to 13μ m on 50μ m SU-8 thickness using direct writing lithography, and width channels of 40 μm for polyimide on SiO2 plate. Finally, we have tested the use of some devices for capillary chips measuring the flow speed for liquids with different viscosities. As a result, we have characterized the presence of liquid in the channel by interferometric microscopy.
Resumo:
A 3-year Project financed by the European Commission is aimed at developing a universal system to de-orbit satellites at their end of life, as a fundamental contribution to limit the increase of debris in the Space environment. The operational system involves a conductive tapetether left bare to establish anodic contact with the ambient plasma as a giant Langmuir probe. The Project will size the three disparate dimensions of a tape for a selected de-orbit mission and determine scaling laws to allow system design for a general mission. Starting at the second year, mission selection is carried out while developing numerical codes to implement control laws on tether dynamics in/off the orbital plane; performing numerical simulations and plasma chamber measurements on tether-plasma interaction; and completing design of subsystems: electronejecting plasma contactor, power module, interface elements, deployment mechanism, and tether-tape/end-mass. This will be followed by subsystems manufacturing and by currentcollection, free-fall, and hypervelocity impact tests.
Resumo:
The objective of the present study is to develop fully renewable and environmentally benign techniques for improving the fire safety of flexible polyurethane foams (PUFs). A multilayered coating made from cationic chitosan (CS) and anionic alginate (AL) was deposited on PUFs through layer-by-layer assembly. This coating system exhibits a slight influence on the thermal stability of PUF, but significantly improves the char formation during combustion. Cone calorimetry reveals that 10 CS-AL bilayers (only 5.7% of the foams weight) lead to a 66% and 11% reduction in peak heat release rate and total heat release, respectively, compared with those of the uncoated control. The notable decreased fire hazards of PUF are attributed to the CS-AL coatings being beneficial to form an insulating protective layer on the surface of burning materials that inhibits the oxygen and heat permeation and slows down the flammable gases in the vapor phase, and thereby improves the flame resistance. This water-based, environmentally benign natural coating will stimulate further efforts in improving fire safety for a variety of polymer substrates.
Resumo:
El sector de la edificación es uno de los principales sectores económicos en España y, además, es un componente básico de la actividad económica y social, debido a su importante papel como generador de empleo, proveedor de bienes e incentivador del crecimiento. Curiosamente, es uno de los sectores con menos regulación y organización y que, además, está formado mayoritariamente por empresas de pequeña y mediana dimensión (pymes) que, por su menor capacidad, a menudo, se quedan detrás de las grandes empresas en términos de adopción de soluciones innovadoras. La complejidad en la gestión de toda la información relacionada con un proyecto de edificación ha puesto de manifiesto claras ineficiencias que se traducen en un gasto innecesario bastante representativo. La información y los conocimientos aprendidos rara vez son transmitidos de una fase a otra dentro del proyecto de edificación y, mucho menos, reutilizados en otros proyectos similares. De este modo, no sólo se produce un gasto innecesario, sino que incluso podemos encontrar información contradictoria y obsoleta y, por tanto, inútil para la toma de decisiones. A lo largo de los años, esta situación ha sido motivada por la propia configuración del sector, poniendo de manifiesto la necesidad de una solución que pudiera solventar este reto de gestión interorganizacional. Así, la cooperación interorganizacional se ha convertido en un factor clave para mejorar la competitividad de las organizaciones, típicamente pymes, que componen el sector de la edificación. La información es la piedra angular de cualquier proceso de negocio. Durante la última década, una amplia gama de industrias han experimentado importantes mejoras de productividad con la aplicación eficiente de las TIC, asociadas, principalmente, a incrementos en la velocidad de proceso de información y una mayor coherencia en la generación de datos, accesibilidad e intercambio de información. La aplicación eficaz de las TIC en el sector de la edificación requiere una combinación de aspectos estratégicos y tácticos, puesto que no sólo se trata de utilizar soluciones puntuales importadas de otros sectores para su aplicación en diferentes áreas, sino que se buscaría que la información multi-agente estuviera integrada y sea coherente para los proyectos de edificación. El sector de la construcción ha experimentado un descenso significativo en los últimos años en España y en Europa como resultado de la crisis financiera que comenzó en 2007. Esta disminución está acompañada de una baja penetración de las TIC en la interorganizacionales orientadas a los procesos de negocio. El descenso del mercado ha provocado una desaceleración en el sector de la construcción, donde sólo las pymes flexibles han sido capaces de mantener el ritmo a pesar de la especialización y la innovación en los servicios adaptados a las nuevas demandas del mercado. La industria de la edificación está muy fragmentada en comparación con otras industrias manufactureras. El alto grado de esta fragmentación está íntimamente relacionado con un impacto significativo en la productividad y el rendimiento. Muchos estudios de investigación han desarrollado y propuesto una serie de modelos de procesos integrados. Por desgracia, en la actualidad todavía no se está en condiciones para la formalización de cómo debe ser la comunicación y el intercambio de información durante el proceso de construcción. El paso del proceso secuencial tradicional a los procesos de interdependencia recíproca sin lugar a duda son una gran demanda asociada a la comunicación y el flujo de información en un proyecto de edificación. Recientemente se está poniendo mucho énfasis en los servicios para el hogar como un primer paso hacia esta mejora en innovación ya que la industria de los servicios digitales interactivos tiene un alto potencial para generar innovación y la ventaja estratégica para las empresas existentes. La multiplicidad de servicios para el hogar digital (HD) y los proveedores de servicios demandan, cada vez más, la aparición de una plataforma capaz de coordinar a todos los agentes del sector con el usuario final. En consecuencia, las estructuras organizacionales tienden a descentralizarse en busca de esa coordinación y, como respuesta a esta demanda, se plantea, también en este ámbito, el concepto de cooperación interorganizacional. Por lo tanto, ambos procesos de negocio -el asociado a la construcción y el asociado a la provisión de servicios del hogar digital, también considerado como la propia gestión de ese hogar digital o edificio, inteligente o no- deben de ser vistos en su conjunto mediante una plataforma tecnológica que les dé soporte y que pueda garantizar la agregación e integración de los diversos procesos, relacionados con la construcción y gestión, que se suceden durante el ciclo de vida de un edificio. Sobre esta idea y atendiendo a la evolución permanente de los sistemas de información en un entorno de interrelación y cooperación daría lugar a una aplicación del concepto de sistema de información interorganizacional (SIIO). El SIIO proporciona a las organizaciones la capacidad para mejorar los vínculos entre los socios comerciales a lo largo de la cadena de suministro, por lo que su importancia ha sido reconocida por organizaciones de diversos sectores. Sin embargo, la adopción de un SIIO en diferentes ámbitos ha demostrado ser complicada y con una alta dependencia de las características particulares de cada sector, siendo, en este momento, una línea de investigación abierta. Para contribuir a esta línea de investigación, este trabajo pretende recoger, partiendo de una revisión de la literatura relacionada, un enfoque en un modelo de adopción de un SIIO para el objeto concreto de esta investigación. El diseño de un SIIO está basado principalmente, en la identificación de las necesidades de información de cada uno de sus agentes participantes, de ahí la importancia en concretar un modelo de SIIO en el ámbito de este trabajo. Esta tesis doctoral presenta el modelo de plataforma virtual de la asociación entre diferentes agentes del sector de la edificación, el marco de las relaciones, los flujos de información correspondientes a diferentes procesos y la metodología que subyace tras el propio modelo, todo ello, con el objeto de contribuir a un modelo unificado que dé soporte tanto a los procesos relacionados con la construcción como con la gestión de servicios en el hogar digital y permitiendo cubrir los requisitos importantes que caracterizan este tipo de proyectos: flexibilidad, escalabilidad y robustez. El SIIO se ha convertido en una fuente de innovación y una herramienta estratégica que permite a las pymes obtener ventajas competitivas. Debido a la complejidad inherente de la adopción de un SIIO, esta investigación extiende el modelo teórico de adopción de un SIIO de Kurnia y Johnston (2000) con un modelo empírico para la caracterización de un SIIO. El modelo resultante tiene como objetivo fomentar la innovación de servicios en el sector mediante la identificación de los factores que influyen en la adopción de un SIIO por las pymes en el sector de la edificación como fuente de ventaja competitiva y de colaboración. Por tanto, esta tesis doctoral, proyectada sobre una investigación empírica, proporciona un enfoque para caracterizar un modelo de SIIO que permita dar soporte a la gestión integrada de los procesos de construcción y gestión de servicios para el hogar digital. La validez del modelo de SIIO propuesto, como fuente y soporte de ventajas competitivas, está íntimamente relacionada con la necesidad de intercambio de información rápido y fiable que demandan los agentes del sector para mejorar la gestión de su interrelación y cooperación con el fin de abordar proyectos más complejos en el sector de la edificación, relacionados con la implantación del hogar digital, y contribuyendo, así a favorecer el desarrollo de la sociedad de la información en el segmento residencial. ABSTRACT The building industry is the largest industry in the world. Land purchase, building design, construction, furnishing, building equipment, operations maintenance and the disposition of real estate have an unquestionable prominence not only at economic but also at social level. In Spain, the building sector is one of the main drivers of economy and also a basic component of economic activity and its role in generating employment, supply of goods or incentive for growth is crucial in the evolution of the economy. Surprisingly, it is one of the sectors with less regulation and organization. Another consistent problem is that, in this sector, the majority of companies are small and medium (SMEs), and often behind large firms in terms of their adoption of innovative solutions. The complexity of managing all information related to this industry has lead to a waste of money and time. The information and knowledge gathered is frequently stored in multiple locations, involving the work of thousands of people, and is rarely transferred on to the next phase. This approach is inconsistent and makes that incorrect information is used for decisions. This situation needs a viable solution for interorganizational information management. So, interorganizational co-operation has become a key factor for organization competitiveness within the building sector. Information is the cornerstone of any business process. Therefore, information and communication technologies (ICT) offer a means to change the way business is conducted. During the last decade, significant productivity improvements were experienced by a wide range of industries with ICT implementation. ICT has provided great advantages in speed of operation, consistency of data generation, accessibility and exchange of information. The wasted money resulting from reentering information, errors and omissions caused through poor decisions and actions, and the delays caused while waiting for information, represent a significant percentage of the global benefits. The effective application of ICT in building construction sector requires a combination of strategic and tactical developments. The building sector has experienced a significant decline in recent years in Spain and in Europe as a result of the financial crisis that began in 2007. This drop goes hand in hand with a low penetration of ICT in inter-organizational-oriented business processes. The market decrease has caused a slowdown in the building sector, where only flexible SMEs have been able to keep the pace though specialization and innovation in services adapted to new market demands. The building industry is highly fragmented compared with other manufacturing industries. This fragmentation has a significant negative impact on productivity and performance. Many research studies have developed and proposed a number of integrated process models. Unfortunately, these studies do not suggest how communication and information exchange within the construction process can be achieved, without duplication or lost in quality. A change from the traditional sequential process to reciprocal interdependency processes would increase the demand on communication and information flow over the edification project. Focusing on home services, the digital interactive service industry has the potential to generate innovation and strategic advantage for existing business. Multiplicity of broadband home services (BHS) and suppliers suggest the need for a figure able to coordinate all the agents in sector with the final user. Consequently, organizational structures tend to be decentralized. Responding to this fact, the concept of interorganizational co-operation also is raising in the residential market. Therefore, both of these business processes, building and home service supply, must be complemented with a technological platform that supports these processes and guarantees the aggregation and integration of the several services over building lifecycle. In this context of a technological platform and the permanent evolution of information systems is where the relevance of the concept of inter-organizational information system (IOIS) emerges. IOIS improves linkages between trading partners along the supply chain. However, IOIS adoption has proved to be difficult and not fully accomplished yet. This research reviews the literature in order to focus a model of IOIS adoption. This PhD Thesis presents a model of virtual association, a framework of the relationships, an identification of the information requirements and the corresponding information flows, using the multi-agent system approach. IOIS has become a source of innovation and a strategic tool for SMEs to obtain competitive advantage. Because of the inherent complexity of IOIS adoption, this research extends Kurnia and Johnston’s (2000) theoretical model of IOIS adoption with an empirical model of IOIS characterization. The resultant model aims to foster further service innovation in the sector by identifying the factors influencing IOIS adoption by the SMEs in the building sector as a source of competitive and collaborative advantage. Therefore, this PhD Thesis characterizes an IOIS model to support integrated management of building processes and home services. IOIS validity, as source and holder of competitive advantages, is related to the need for reliable information interchanges to improve interrelationship management. The final goal is to favor tracking of more complex projects in building sector and to contribute to consolidation of the information society through the provision of broadband home services and home automation.
Resumo:
The current research aims to analyse theoretically and evaluate a self-manufactured simple design for subsurface drip irrigation (SDI) emitter to avoid root and soil intrusion. It was composed of three concentric cylindrical elements: an elastic silicone membrane; a polyethylene tube with two holes drilled on its wall for water discharge; and a vinyl polychloride protector system to wrap the other elements. The discharge of the emitter depends on the change in the membrane diameter when it is deformed by the water pressure. The study of the operation of this emitter is a new approach that considers mechanical and hydraulic principles. Thus, the estimation on the membrane deformation was based on classical mechanical stress theories in composite cylinders. The hydraulic principles considered the solid deformation due to force based on water pressure and the general Darcy–Weisbach head-loss equation. Twenty emitter units, with the selected design, were handcrafted in a lathe and were used in this study. The measured pressure/discharge relationship for the emitters showed good agreement with that calculated by the theoretical approach. The variation coefficient of the handcrafted emitters was high compared to commercial emitters. Results from field evaluations showed variable values for the relative flow variation, water emission uniformity and relative flow rate coefficients, but no emitter was obstructed. Therefore, the current emitter design could be suitable for SDI following further studies to develop a final prototype.
Resumo:
Automated Teller Machines (ATMs) are sensitive self-service systems that require important investments in security and testing. ATM certifications are testing processes for machines that integrate software components from different vendors and are performed before their deployment for public use. This project was originated from the need of optimization of the certification process in an ATM manufacturing company. The process identifies compatibility problems between software components through testing. It is composed by a huge number of manual user tasks that makes the process very expensive and error-prone. Moreover, it is not possible to fully automate the process as it requires human intervention for manipulating ATM peripherals. This project presented important challenges for the development team. First, this is a critical process, as all the ATM operations rely on the software under test. Second, the context of use of ATMs applications is vastly different from ordinary software. Third, ATMs’ useful lifetime is beyond 15 years and both new and old models need to be supported. Fourth, the know-how for efficient testing depends on each specialist and it is not explicitly documented. Fifth, the huge number of tests and their importance implies the need for user efficiency and accuracy. All these factors led us conclude that besides the technical challenges, the usability of the intended software solution was critical for the project success. This business context is the motivation of this Master Thesis project. Our proposal focused in the development process applied. By combining user-centered design (UCD) with agile development we ensured both the high priority of usability and the early mitigation of software development risks caused by all the technology constraints. We performed 23 development iterations and finally we were able to provide a working solution on time according to users’ expectations. The evaluation of the project was carried out through usability tests, where 4 real users participated in different tests in the real context of use. The results were positive, according to different metrics: error rate, efficiency, effectiveness, and user satisfaction. We discuss the problems found, the benefits and the lessons learned in the process. Finally, we measured the expected project benefits by comparing the effort required by the current and the new process (once the new software tool is adopted). The savings corresponded to 40% less effort (man-hours) per certification. Future work includes additional evaluation of product usability in a real scenario (with customers) and the measuring of benefits in terms of quality improvement.
Resumo:
La robótica ha evolucionado exponencialmente en las últimas décadas, permitiendo a los sistemas actuales realizar tareas sumamente complejas con gran precisión, fiabilidad y velocidad. Sin embargo, este desarrollo ha estado asociado a un mayor grado de especialización y particularización de las tecnologías implicadas, siendo estas muy eficientes en situaciones concretas y controladas, pero incapaces en entornos cambiantes, dinámicos y desestructurados. Por eso, el desarrollo de la robótica debe pasar por dotar a los sistemas de capacidad de adaptación a las circunstancias, de entendedimiento sobre los cambios observados y de flexibilidad a la hora de interactuar con el entorno. Estas son las caracteristicas propias de la interacción del ser humano con su entorno, las que le permiten sobrevivir y las que pueden proporcionar a un sistema inteligencia y capacidad suficientes para desenvolverse en un entorno real de forma autónoma e independiente. Esta adaptabilidad es especialmente importante en el manejo de riesgos e incetidumbres, puesto que es el mecanismo que permite contextualizar y evaluar las amenazas para proporcionar una respuesta adecuada. Así, por ejemplo, cuando una persona se mueve e interactua con su entorno, no evalúa los obstáculos en función de su posición, velocidad o dinámica (como hacen los sistemas robóticos tradicionales), sino mediante la estimación del riesgo potencial que estos elementos suponen para la persona. Esta evaluación se consigue combinando dos procesos psicofísicos del ser humano: por un lado, la percepción humana analiza los elementos relevantes del entorno, tratando de entender su naturaleza a partir de patrones de comportamiento, propiedades asociadas u otros rasgos distintivos. Por otro lado, como segundo nivel de evaluación, el entendimiento de esta naturaleza permite al ser humano conocer/estimar la relación de los elementos con él mismo, así como sus implicaciones en cuanto a nivel de riesgo se refiere. El establecimiento de estas relaciones semánticas -llamado cognición- es la única forma de definir el nivel de riesgo de manera absoluta y de generar una respuesta adecuada al mismo. No necesariamente proporcional, sino coherente con el riesgo al que se enfrenta. La investigación que presenta esta tesis describe el trabajo realizado para trasladar esta metodología de análisis y funcionamiento a la robótica. Este se ha centrado especialmente en la nevegación de los robots aéreos, diseñando e implementado procedimientos de inspiración humana para garantizar la seguridad de la misma. Para ello se han estudiado y evaluado los mecanismos de percepción, cognición y reacción humanas en relación al manejo de riesgos. También se ha analizado como los estímulos son capturados, procesados y transformados por condicionantes psicológicos, sociológicos y antropológicos de los seres humanos. Finalmente, también se ha analizado como estos factores motivan y descandenan las reacciones humanas frente a los peligros. Como resultado de este estudio, todos estos procesos, comportamientos y condicionantes de la conducta humana se han reproducido en un framework que se ha estructurado basadandose en factores análogos. Este emplea el conocimiento obtenido experimentalmente en forma de algoritmos, técnicas y estrategias, emulando el comportamiento humano en las mismas circunstancias. Diseñado, implementeado y validado tanto en simulación como con datos reales, este framework propone una manera innovadora -tanto en metodología como en procedimiento- de entender y reaccionar frente a las amenazas potenciales de una misión robótica. ABSTRACT Robotics has undergone a great revolution in the last decades. Nowadays this technology is able to perform really complex tasks with a high degree of accuracy and speed, however this is only true in precisely defined situations with fully controlled variables. Since the real world is dynamic, changing and unstructured, flexible and non context-dependent systems are required. The ability to understand situations, acknowledge changes and balance reactions is required by robots to successfully interact with their surroundings in a fully autonomous fashion. In fact, it is those very processes that define human interactions with the environment. Social relationships, driving or risk/incertitude management... in all these activities and systems, context understanding and adaptability are what allow human beings to survive: contrarily to the traditional robotics, people do not evaluate obstacles according to their position but according to the potential risk their presence imply. In this sense, human perception looks for information which goes beyond location, speed and dynamics (the usual data used in traditional obstacle avoidance systems). Specific features in the behaviour of a particular element allows the understanding of that element’s nature and therefore the comprehension of the risk posed by it. This process defines the second main difference between traditional obstacle avoidance systems and human behaviour: the ability to understand a situation/scenario allows to get to know the implications of the elements and their relationship with the observer. Establishing these semantic relationships -named cognition- is the only way to estimate the actual danger level of an element. Furthermore, only the application of this knowledge allows the generation of coherent, suitable and adjusted responses to deal with any risk faced. The research presented in this thesis summarizes the work done towards translating these human cognitive/reasoning procedures to the field of robotics. More specifically, the work done has been focused on employing human-based methodologies to enable aerial robots to navigate safely. To this effect, human perception, cognition and reaction processes concerning risk management have been experimentally studied; as well as the acquisition and processing of stimuli. How psychological, sociological and anthropological factors modify, balance and give shape to those stimuli has been researched. And finally, the way in which these factors motivate the human behaviour according to different mindsets and priorities has been established. This associative workflow has been reproduced by establishing an equivalent structure and defining similar factors and sources. Besides, all the knowledge obtained experimentally has been applied in the form of algorithms, techniques and strategies which emulate the analogous human behaviours. As a result, a framework capable of understanding and reacting in response to stimuli has been implemented and validated.
Resumo:
Acoplamiento del sistema informático de control de piso de producción (SFS) con el conjunto de equipos de fabricación (SPE) es una tarea compleja. Tal acoplamiento involucra estándares abiertos y propietarios, tecnologías de información y comunicación, entre otras herramientas y técnicas. Debido a la turbulencia de mercados, ya sea soluciones personalizadas o soluciones basadas en estándares eventualmente requieren un esfuerzo considerable de adaptación. El concepto de acoplamiento débil ha sido identificado en la comunidad de diseño organizacional como soporte para la sobrevivencia de la organización. Su presencia reduce la resistencia de la organización a cambios en el ambiente. En este artículo los resultados obtenidos por la comunidad de diseño organizacional son identificados, traducidos y organizados para apoyar en la solución del problema de integración SFS-SPE. Un modelo clásico de acoplamiento débil, desarrollado por la comunidad de estudios de diseño organizacional, es resumido y trasladado al área de interés. Los aspectos claves son identificados para utilizarse como promotores del acoplamiento débil entre SFS-SPE, y presentados en forma de esquema de referencia. Así mismo, este esquema de referencia es presentado como base para el diseño e implementación de una solución genérica de acoplamiento o marco de trabajo (framework) de acoplamiento, a incluir como etapa de acoplamiento débil entre SFS y SPE. Un ejemplo de validación con varios conjuntos de equipos de fabricación, usando diferentes medios físicos de comunicación, comandos de controlador, lenguajes de programación de equipos y protocolos de comunicación es presentado, mostrando un nivel aceptable de autonomía del SFS. = Coupling shop floor software system (SFS) with the set of production equipment (SPE) becomes a complex task. It involves open and proprietary standards, information and communication technologies among other tools and techniques. Due to market turbulence, either custom solutions or standards based solutions eventually require a considerable effort of adaptation. Loose coupling concept has been identified in the organizational design community as a compensator for organization survival. Its presence reduces organization reaction to environment changes. In this paper the results obtained by the organizational de sign community are identified, translated and organized to support the SFS-SPE integration problem solution. A classical loose coupling model developed by organizational studies community is abstracted and translated to the area of interest. Key aspects are identified to be used as promoters of SFS-SPE loose coupling and presented in a form of a reference scheme. Furthermore, this reference scheme is proposed here as a basis for the design and implementation of a generic coupling solution or coupling framework, that is included as a loose coupling stage between SFS and SPE. A validation example with various sets of manufacturing equipment, using different physical communication media, controller commands, programming languages and wire protocols is presented, showing an acceptable level of autonomy gained by the SFS.
Resumo:
A raíz de la aparición de los procesadores dotados de varios “cores”, la programación paralela, un concepto que, por otra parte no era nada nuevo y se conocía desde hace décadas, sufrió un nuevo impulso, pues se creía que se podía superar el techo tecnológico que había estado limitando el rendimiento de esta programación durante años. Este impulso se ha ido manteniendo hasta la actualidad, movido por la necesidad de sistemas cada vez más potentes y gracias al abaratamiento de los costes de fabricación. Esta tendencia ha motivado la aparición de nuevo software y lenguajes con componentes orientados precisamente al campo de la programación paralela. Este es el caso del lenguaje Go, desarrollado por Google y lanzado en 2009. Este lenguaje se basa en modelos de concurrencia que lo hacen muy adecuados para abordar desarrollos de naturaleza paralela. Sin embargo, la programación paralela es un campo complejo y heterogéneo, y los programadores son reticentes a utilizar herramientas nuevas, en beneficio de aquellas que ya conocen y les son familiares. Un buen ejemplo son aquellas implementaciones de lenguajes conocidos, pero orientadas a programación paralela, y que siguen las directrices de un estándar ampliamente reconocido y aceptado. Este es el caso del estándar OpenMP, un Interfaz de Programación de Aplicaciones (API) flexible, portable y escalable, orientado a la programación paralela multiproceso en arquitecturas multi-core o multinucleo. Dicho estándar posee actualmente implementaciones en los lenguajes C, C++ y Fortran. Este proyecto nace como un intento de aunar ambos conceptos: un lenguaje emergente con interesantes posibilidades en el campo de la programación paralela, y un estándar reputado y ampliamente extendido, con el que los programadores se encuentran familiarizados. El objetivo principal es el desarrollo de un conjunto de librerías del sistema (que engloben directivas de compilación o pragmas, librerías de ejecución y variables de entorno), soportadas por las características y los modelos de concurrencia propios de Go; y que añadan funcionalidades propias del estándar OpenMP. La idea es añadir funcionalidades que permitan programar en lenguaje Go utilizando la sintaxis que OpenMP proporciona para otros lenguajes, como Fortan y C/C++ (concretamente, similar a esta última), y, de esta forma, dotar al usuario de Go de herramientas para programar estructuras de procesamiento paralelo de forma sencilla y transparente, de la misma manera que lo haría utilizando C/C++.---ABSTRACT---As a result of the appearance of processors equipped with multiple "cores ", parallel programming, a concept which, moreover, it was not new and it was known for decades, suffered a new impulse, because it was believed they could overcome the technological ceiling had been limiting the performance of this program for years. This impulse has been maintained until today, driven by the need for ever more powerful systems and thanks to the decrease in manufacturing costs. This trend has led to the emergence of new software and languages with components guided specifically to the field of parallel programming. This is the case of Go language, developed by Google and released in 2009. This language is based on concurrency models that make it well suited to tackle developments in parallel nature. However, parallel programming is a complex and heterogeneous field, and developers are reluctant to use new tools to benefit those who already know and are familiar. A good example are those implementations from well-known languages, but parallel programming oriented, and witch follow the guidelines of a standard widely recognized and accepted. This is the case of the OpenMP standard, an application programming interface (API), flexible, portable and scalable, parallel programming oriented, and designed for multi-core architectures. This standard currently has implementations in C, C ++ and Fortran. This project was born as an attempt to combine two concepts: an emerging language, with interesting possibilities in the field of parallel programming, and a reputed and widespread standard, with which programmers are familiar with. The main objective is to develop a set of system libraries (which includes compiler directives or pragmas, runtime libraries and environment variables), supported by the characteristics and concurrency patterns of Go; and that add custom features from the OpenMP standard. The idea is to add features that allow programming in Go language using the syntax OpenMP provides for other languages, like Fortran and C / C ++ (specifically, similar to the latter ), and, in this way, provide Go users with tools for programming parallel structures easily and, in the same way they would using C / C ++.
Resumo:
La construcción en la actualidad de nuevas fuentes para el uso de haces de neutrones así como los programas de renovación en curso en algunas de las instalaciones experimentales existentes han evidenciado la necesidad urgente de desarrollar la tecnología empleada para la construcción de guías de neutrones con objeto de hacerlas mas eficientes y duraderas. Esto viene motivado por el hecho de que varias instalaciones de experimentación con haces de neutrones han reportado un número de incidentes mecánicos con tales guías, lo que hace urgente el progresar en nuestro conocimiento de los susbtratos vítreos sobre los cuales se depositan los espejos que permiten la reflexión total de los neutrones y como aquellos se degradan con la radiación. La presente tesis se inscribe en un acuerdo de colaboración establecido entre el Institut Max von Laue - Paul Langevin (ILL) de Grenoble y el Consorcio ESS-Bilbao con objeto de mejorar el rendimiento y sostenibilidad de los sistemas futuros de guiado de neutrones. El caso de la Fuente Europea de Espalación en construcción en Lund sirve como ejemplo ya que se contempla la instalación de guías de neutrones de más de 100 metros en algunos de los instrumentos. Por otro lado, instalaciones como el ILL prevén también dentro del programa Endurance de rejuvenecimiento la reconstrucción de varias líneas de transporte de haz. Para el presente estudio se seleccionaron cuatro tipos de vidrios borosilicatados que fueron el Borofloat, N-ZK7, N-BK7 y SBSL7. Los tres primeros son bien conocidos por los especialistas en instrumentación neutrónica ya que se han empleado en la construcción de varias instalaciones mientras que el último es un candidato potencial en la fabricación de substratos para espejos neutrónicos en un futuro. Los cuatro vidrios tiene un contenido en óxido de Boro muy similar, approximadamente un 10 mol.%. Tal hecho que obedece a las regulaciones para la fabricación de estos dispositivos hace que tales substratos operen como protección radiológica absorbiendo los neutrones transmitidos a través del espejo de neutrones. Como contrapartida a tal beneficio, la reacción de captura 10B(n,_)7Li puede degradar el substrato vítreo debido a los 2.5 MeV de energía cinética depositados por la partícula _ y los núcleos en retroceso y de hecho la fragilidad de tales vidrios bajo radiación ha sido atribuida desde hace ya tiempo a los efectos de esta reacción. La metodología empleada en esta tesis se ha centrado en el estudio de la estructura de estos vidrios borosilicatados y como esta se comporta bajo condiciones de radiación. Los materiales en cuestión presentan estructuras que dependen de su composición química y en particular del ratio entre formadores y modificadores de la red iono-covalente. Para ello se han empleado un conjunto de técnicas de caracterización tanto macro- como microscópicas tales como estudios de dureza, TEM, Raman, SANS etc. que se han empleado también para determinar el comportamiento de estos materiales bajo radiación. En particular, algunas propiedades macroscópicas relacionadas con la resistencia de estos vidrios como elementos estructurales de las guías de neutrones han sido estudiadas así como también los cambios en la estructura vítrea consecuencia de la radiación. Para este propósito se ha diseñado y fabricado por el ILL un aparato para irradiación de muestras con neutrones térmicos en el reactor del ILL que permite controlar la temperatura alcanzada por la muestra a menos de 100 °C. Tal equipo en comparación con otros ya existences permite en cuestión de dias acumular las dosis recibidas por una guía en operación a lo largo de varios años. El uso conjunto de varias técnicas de caracterización ha llevado a revelar que los vidrios aqui estudiados son significativamente diferentes en cuanto a su estructura y que tales diferencias afectan a sus propiedades macroscópicas asi como a su comportamiento bajo radiación. Tal resultado ha sido sorprendente ya que, como se ha mencionado antes, algunos de estos vidrios eran bien conocidos por los fabricantes de guías de neutrones y hasta el momento eran considerados prácticamente similares debido a su contenido comparable en óxido de Boro. Sin embargo, los materiales N-BK7 and S-BSL7 muetran gran homogeneidad a todas las escalas de longitud, y más específicamente, a escalas nanométricas las subredes de Sílice y óxido de Boro se mezclan dando logar a estructuras locales que recuerdan a la del cristal de Reedmergnerita. Por el contrario, N-ZK7 y Borofloat muestran dominios separados ricos en Sílice o Boro. Como era de esperar, las importantes diferencias arriba mencionadas se traducen en comportamientos dispares de estos materiales bajo un haz de neutrones térmicos. Los resultados muestran que el N-BK7 y el S-BSL7 son los más estables bajo radiación, lo que macroscópicamente hace que estos materiales muestren un comportamiento similar expandiéndose lentamente en función de la dosis recibida. Por el contario, los otros dos materiales muestran un comportamiento mucho más reactivo, que hace que inicialmente se compacten con la dosis recibida lo que hace que las redes de Silicio y Boro se mezclen resultando en un incremento en densidad hasta alcanzar un valor límite, seguido por un proceso de expansión lenta que resulta comparable al observado para N-BK7 y SBSL7. Estos resultados nos han permitido explicar el origen de las notorias diferencias observadas en cuanto a las dosis límite a partir de las cuales estos materiales desarrollan procesos de fragmentación en superficie. ABSTRACT The building of new experimental neutron beam facilities as well as the renewal programmes under development at some of the already existing installations have pinpointed the urgent need to develop the neutron guide technology in order to make such neutron transport devices more efficient and durable. In fact, a number of mechanical failures of neutron guides have been reported by several research centres. It is therefore important to understand the behaviour of the glass substrates on top of which the neutron optics mirrors are deposited and how these materials degrade under radiation conditions. The case of the European Spallation Source (ESS) at present under construction at Lund is a good example. It previews the deployment of neutron guides having more than 100 metres of length for most of the instruments. Also, the future renovation programme of the ILL, called Endurance, foresees the refurbishment of several beam lines. This Ph.D. thesis was the result of a collaboration agreement between the ILL and ESS-Bilbao aiming to improve the performance and sustainability of future neutron delivery systems. Four different industrially produced alkali-borosilicate glasses were selected for this study: Borofloat, N-ZK7, N-BK7 and SBSL7. The first three are well known within the neutron instrumentation community as they have already been used in several installations whereas the last one is at present considered as a candidate for making future mirror substrates. All four glasses have a comparable content of boron oxide of about 10 mol.%. The presence of such a strong neutron absorption element is in fact a mandatory component for the manufacturing of neutron guides because it provides a radiological shielding for the environment. This benefit is however somewhat counterbalanced since the resulting 10B(n,_)7Li reactions degrade the glass due to the deposited energy of 2.5 MeV by the _ particle and the recoil nuclei. In fact, the brittleness of some of these materials has been ascribed to this reaction. The methodology employed by this study consisted in understanding the general structure of borosilicates and how they behave under irradiation. Such materials have a microscopic structure strongly dependent upon their chemical content and particularly on the ratios between network formers and modifiers. The materials have been characterized by a suite of macroscopic and structural techniques such as hardness, TEM, Raman, SANS, etc. and their behaviour under irradiation was analysed. Some macroscopic properties related to their resistance when used as guide structural elements were monitored. Also, changes in the vitreous structure due to radiation were observed by means of several experimental tools. For such a purpose, an irradiation apparatus has been designed and manufactured to enable irradiation with thermal neutrons within the ILL reactor while keeping the samples below 100 °C. The main advantage of this equipment if compared to others previously available was that it allowed to reach in just some days an equivalent neutron dose to that accumulated by guides after several years of use. The concurrent use of complementary characterization techniques lead to the discovery that the studied glasses were deeply different in terms of their glass network. This had a strong impact on their macroscopic properties and their behaviour under irradiation. This result was a surprise since, as stated above, some of these materials were well known by the neutron guide manufacturers, and were considered to be almost equivalent because of their similar boron oxide content. The N-BK7 and S-BSL7 materials appear to be fairly homogeneous glasses at different length scales. More specifically, at nanometre scales, silicon and boron oxide units seem to mix and generate larger structures somewhat resembling crystalline Reedmergnerite. In contrast, N-ZK7 and Borofloat are characterized by either silicon or boron rich domains. As one could expect, these drastic differences lead to their behaviour under thermal neutron flux. The results show that N-BK7 and S-BSL7 are structurally the most stable under radiation. Macroscopically, such stability results in the fact that these two materials show very slow swelling as a function or radiation dose. In contrast, the two other glasses are much more reactive. The whole glass structure compacts upon radiation. Specifically, the silica network, and the boron units tend to blend leading to an increase in density up to some saturation, followed by a very slow expansion which comes to be of the same order than that shown by N-BK7 and S-BSL7. Such findings allowed us to explain the drastic differences in the radiation limits for macroscopic surface splintering for these materials when they are used in neutron guides.