50 resultados para LARGE SYSTEMS

em Universidad Politécnica de Madrid


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Security intrusions in large systems is a problem due to its lack of scalability with the current IDS-based approaches. This paper describes the RECLAMO project, where an architecture for an Automated Intrusion Response System (AIRS) is being proposed. This system will infer the most appropriate response for a given attack, taking into account the attack type, context information, and the trust and reputation of the reporting IDSs. RECLAMO is proposing a novel approach: diverting the attack to a specific honeynet that has been dynamically built based on the attack information. Among all components forming the RECLAMO's architecture, this paper is mainly focused on defining a trust and reputation management model, essential to recognize if IDSs are exposing an honest behavior in order to accept their alerts as true. Experimental results confirm that our model helps to encourage or discourage the launch of the automatic reaction process.

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The increasing complexity of current software systems is encouraging the development of self-managed software architectures, i.e. systems capable of reconfiguring their structure at runtime to fulfil a set of goals. Several approaches have covered different aspects of their development, but some issues remain open, such as the maintainability or the scalability of self-management subsystems. Centralized approaches, like self-adaptive architectures, offer good maintenance properties but do not scale well for large systems. On the contrary, decentralized approaches, like self-organising architectures, offer good scalability but are not maintainable: reconfiguration specifications are spread and often tangled with functional specifications. In order to address these issues, this paper presents an aspect-oriented autonomic reconfiguration approach where: (1) each subsystem is provided with self-management properties so it can evolve itself and the components that it is composed of; (2) self-management concerns are isolated and encapsulated into aspects, thus improving its reuse and maintenance. Povzetek: Predstavljen je pristop s samo-preoblikovanjem programske arhitekture.

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La expansión experimentada por la informática, las nuevas tecnologías e internet en los últimos años, no solo viene dada por la evolución del hardware subyacente, sino por la evolución del desarrollo de software y del crecimiento del número de desarrolladores. Este incremento ha hecho evolucionar el software de unos sistemas de gestión basados en ficheros, prácticamente sin interfaz gráfico y de unos pocos miles de líneas a grandes sistemas distribuidos multiplataforma. El desarrollo de estos grandes sistemas, requiere gran cantidad de personas involucradas en el desarrollo, y que las herramientas de desarrollo hayan crecido también para facilitar su análisis, diseño, codificación, pruebas, implantación y mantenimiento. La base de estas herramientas software las proveen las propias plataformas de desarrollo, pero la experiencia de los desarrolladores puede aportar un sinfín de utilidades y de técnicas que agilicen los desarrollos y cumplan los requisitos del software en base a la reutilización de soluciones lo suficientemente probadas y optimizadas. Dichas herramientas se agrupan ordenadamente, creando así frameworks personalizados, con herramientas de todo tipo, clases, controles, interfaces, patrones de diseño, de tal manera que se dan soluciones personalizadas a un amplio número de problemas para emplearlas cuantas veces se quiera, bien marcando directrices de desarrollo mediante el uso de patrones, bien con la encapsulación de complejidades de tal modo que los desarrolladores ya dispongan de componentes que asuman cierta lógica o cierta complejidad aliviando así la fase de construcción. En este trabajo se abordan temas sobre las tecnologías base y plataformas de desarrollo para poder acometer la creación de un framework personalizado, necesidades a evaluar antes de acometerlo, y técnicas a emplear para la consecución del mismo, orientadas a la documentación, mantenimiento y extensión del framework. La exposición teórica consiste en mostrar y evaluar los requisitos para crear un framework, requisitos de la plataforma de desarrollo, y explicar cómo funcionan las grandes plataformas de desarrollo actuales, que elementos los componen y su funcionamiento, así como marcar ciertas pautas de estructuración y nomenclatura que el desarrollo de un framework debe contemplar para su mantenimiento y extensión. En la parte metodológica se ha usado un subconjunto de Métrica V3, ya que para el desarrollo de controles no aplica dicha metodología en su totalidad, pero contempla el catálogo de requisitos, los casos de uso, diagramas de clase, diagramas de secuencia, etc… Aparte de los conceptos teóricos, se presenta un caso práctico con fines didácticos de cómo parametrizar y configurar el desarrollo bajo la plataforma .NET. Dicho caso práctico consiste en la extensión de un control de usuario genérico de la plataforma .NET, de tal modo que se aplican conceptos más allá del hecho de crear funciones como las funcionalidades que puede brindar un API. Conceptos sobre como extender y modificar controles ya existentes, que interactúan por medio de eventos con otros controles, con vistas a que ese nuevo control forme parte de una biblioteca de controles de usuario personalizados ampliamente divulgada. Los controles de usuario son algo que no solo tienen una parte funcional, sino que también tienen una parte visual, y definiciones funcionales distintas de las típicas del software de gestión, puesto que han de controlar eventos, visualizaciones mientras se dan estos eventos y requisitos no funcionales de optimización de rendimiento, etc… Para el caso práctico se toma como herramienta la plataforma de desarrollo .Net Framework, en todas sus versiones, ya que el control a extender es el control ListView y hacerlo editable. Este control está presente en todas las versiones de .NET framework y con un alto grado de reutilización. Esta extensión muestra además como se puede migrar fácilmente este tipo de extensiones sobre todos los frameworks. Los entornos de desarrollo usados son varias versiones de Visual Studio para el mostrar dicha compatibilidad, aunque el desarrollo que acompaña este documento esté realizado sobre Visual Studio 2013. ABSTRACT The expansion in computer science, new technologies and the Internet in recent years, not only is given by the evolution of the underlying hardware, but for the evolution of software development and the growing number of developers. This increase has evolved software from management systems based on files almost without graphical interface and a few thousand of code lines, to large multiplatform distributed systems. The development of these large systems, require lots of people involved in development, and development tools have also grown to facilitate analysis, design, coding, testing, deployment and maintenance. The basis of these software tools are providing by their own development platforms, but the experience of the developers can bring a lot of utilities and techniques to speed up developments and meet the requirements of software reuse based on sufficiently proven solutions and optimized. These tools are grouped neatly, creating in this way custom frameworks, with tools of all types, classes, controls, interfaces, design patterns,… in such a way that they provide customized solutions to a wide range of problems to use them many times as you want to occur, either by dialing development guidelines by using patterns or along with the encapsulation of complexities, so that developers already have components that take some logic or some complexity relieving the construction phase. This paper cover matters based on technologies and development platforms to undertake the creation of a custom framework, needs to evaluate before rush it and techniques to use in order to achieve it, a part from techniques oriented to documentation, maintenance and framework extension. The theoretical explanation consists in to demonstrate and to evaluate the requirements for creating a framework, development platform requirements, and explain how large current development platforms work, which elements compose them and their operation work, as well as mark certain patterns of structure and nomenclature that the development of a framework should include for its maintenance and extension. In the methodological part, a subset of Métrica V3 has been used, because of, for the development of custom controls this methodology does not apply in its entirety, but provides a catalogue of requirements, use cases, class diagrams, sequence diagrams, etc ... Apart from the theoretical concepts, a study case for teaching purposes about how to parameterize and configure the development under the .NET platform is presented. This study case involves the extension of a generic user control of the .NET platform, so that concepts apply beyond the fact of creating functions as the functionalities that can provide an API. Concepts on how to extend and modify existing controls that interact through events with other controls, overlooking that new control as a part of a custom user controls library widely publicized. User controls are something that not only have a functional part, but also have a visual part, and various functional definitions of typical management software, since that they have to control events, visualizations while these events are given and not functional of performance optimization requirements, etc ... For the study case the development platform .Net Framework is taken as tool, in all its versions, considering that control to extend is the ListView control and make it editable. This control is present in all versions of .NET framework and with a high degree of reuse. This extension also shows how you can easily migrate these extensions on all frameworks. The used development environments are several versions of Visual Studio to show that compatibility, although the development that accompanies this document is done on Visual Studio 2013.

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Las gemas se evalúan mediante la norma de clasificación visual (UNE 56544), pero su aplicación en estructuras existentes y grandes escuadrías resulta poco eficaz y conduce a estimaciones demasiado conservadoras. Este trabajo analiza la influencia de las gemas comparando la resistencia de piezas con gemas y piezas correctamente escuadradas. Se han analizado 218 piezas de pino silvestre con dimensiones nominales 150 x 200 x 4.200 mm, de las que 102 presentaban una gema completa a lo largo de toda su longitud y el resto estaban correctamente escuadradas. En las piezas con gema se ha medido la altura de la sección cada 30 cm (altura en cada cara y altura máxima). Para determinar la resistencia se han ensayado todas las piezas de acuerdo a la norma EN 408. Se ha comparado la resistencia obtenida para las piezas con gema, diferenciando si la gema se encuentra en el borde comprimido o en el borde traccionado, con las piezas escuadradas. Puede concluirse que la presencia de gemas disminuye la resistencia excepto si la gema se encuentra en el borde traccionado, en cuyo caso los resultados obtenidos han sido similares a los de las piezas escuadradas. The wanes on structural timber are evaluated according to the visual grading standard (UNE 56544), but its application on existing structures and large cross sections is ineffective and leads to conservative estimations. This paper analyzes the influence of the wanes by comparing the resistance of pieces with wanes and square pieces. 218 pieces of Scotch pine with nominal dimensions 150 x 200 x 4200 mm have been analyzed, 102 of them had a complete wane along its length and the rest were properly squared. The height of the cross section was measured every 30 cm (the height on each side and the maximum height) for the pieces with wane. The bending strength of all the pieces was obtained according to the EN 408 standard. The bending strength of the pieces with wane has been compared with the strength of the squared pieces, taking into account if the wane is positioned on the compressed edge or on the tensioned edge. It can be concluded that the bending strength of the pieces with wanes is lower than the one of squared pieces, except if the wanes are on the tensioned edge of the beam.

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The computational study commented by Touchette opens the door to a desirable generalization of standard large deviation theory for special, though ubiquitous, correlations. We focus on three interrelated aspects: (i) numerical results strongly suggest that the standard exponential probability law is asymptotically replaced by a power-law dominant term; (ii) a subdominant term appears to reinforce the thermodynamically extensive entropic nature of q-generalized rate function; (iii) the correlations we discussed, correspond to Q -Gaussian distributions, differing from Lévy?s, except in the case of Cauchy?Lorentz distributions. Touchette has agreeably discussed point (i), but, unfortunately, points (ii) and (iii) escaped to his analysis. Claiming the absence of connection with q-exponentials is unjustified.

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Smart Grids are advanced power networks that introduce intelligent management, control, and operation systems to address the new challenges generated by the growing energy demand and the appearance of renewal energies. In the literature, Smart Grids are presented as an exemplar SoS: systems composed of large heterogeneous and independent systems that leverage emergent behavior from their interaction. Smart Grids are currently scaling up the electricity service to millions of customers. These Smart Grids are known as Large-Scale Smart Grids. From the experience in several projects about Large-Scale Smart Grids, this paper defines Large-Scale Smart Grids as a SoS that integrate a set of SoS and conceptualizes the properties of this SoS. In addition, the paper defines the architectural framework for deploying the software architectures of Large-Scale Smart Grid SoS.

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Experiences in decentralized rural electrification programmes using solar home systems have suffered difficulties during the operation and maintenance phase, due in many cases, to the underestimation of the maintenance cost, because of the decentralized character of the activity, and also because the reliability of the solar home system components is frequently unknown. This paper reports on the reliability study and cost characterization achieved in a large photovoltaic rural electrification programme carried out in Morocco. The paper aims to determinate the reliability features of the solar systems, focusing in the in-field testing for batteries and photovoltaic modules. The degradation rates for batteries and PV modules have been extracted from the in-field experiments. On the other hand, the main costs related to the operation and maintenance activity have been identified with the aim of establishing the main factors that lead to the failure of the quality sustainability in many rural electrification programmes.

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Nowadays computing platforms consist of a very large number of components that require to be supplied with diferent voltage levels and power requirements. Even a very small platform, like a handheld computer, may contain more than twenty diferent loads and voltage regulators. The power delivery designers of these systems are required to provide, in a very short time, the right power architecture that optimizes the performance, meets electrical specifications plus cost and size targets. The appropriate selection of the architecture and converters directly defines the performance of a given solution. Therefore, the designer needs to be able to evaluate a significant number of options in order to know with good certainty whether the selected solutions meet the size, energy eficiency and cost targets. The design dificulties of selecting the right solution arise due to the wide range of power conversion products provided by diferent manufacturers. These products range from discrete components (to build converters) to complete power conversion modules that employ diferent manufacturing technologies. Consequently, in most cases it is not possible to analyze all the alternatives (combinations of power architectures and converters) that can be built. The designer has to select a limited number of converters in order to simplify the analysis. In this thesis, in order to overcome the mentioned dificulties, a new design methodology for power supply systems is proposed. This methodology integrates evolutionary computation techniques in order to make possible analyzing a large number of possibilities. This exhaustive analysis helps the designer to quickly define a set of feasible solutions and select the best trade-off in performance according to each application. The proposed approach consists of two key steps, one for the automatic generation of architectures and other for the optimized selection of components. In this thesis are detailed the implementation of these two steps. The usefulness of the methodology is corroborated by contrasting the results using real problems and experiments designed to test the limits of the algorithms.

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Managing large medical image collections is an increasingly demanding important issue in many hospitals and other medical settings. A huge amount of this information is daily generated, which requires robust and agile systems. In this paper we present a distributed multi-agent system capable of managing very large medical image datasets. In this approach, agents extract low-level information from images and store them in a data structure implemented in a relational database. The data structure can also store semantic information related to images and particular regions. A distinctive aspect of our work is that a single image can be divided so that the resultant sub-images can be stored and managed separately by different agents to improve performance in data accessing and processing. The system also offers the possibility of applying some region-based operations and filters on images, facilitating image classification. These operations can be performed directly on data structures in the database.

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Geographic Information Systems are developed to handle enormous volumes of data and are equipped with numerous functionalities intended to capture, store, edit, organise, process and analyse or represent the geographically referenced information. On the other hand, industrial simulators for driver training are real-time applications that require a virtual environment, either geospecific, geogeneric or a combination of the two, over which the simulation programs will be run. In the final instance, this environment constitutes a geographic location with its specific characteristics of geometry, appearance, functionality, topography, etc. The set of elements that enables the virtual simulation environment to be created and in which the simulator user can move, is usually called the Visual Database (VDB). The main idea behind the work being developed approaches a topic that is of major interest in the field of industrial training simulators, which is the problem of analysing, structuring and describing the virtual environments to be used in large driving simulators. This paper sets out a methodology that uses the capabilities and benefits of Geographic Information Systems for organising, optimising and managing the visual Database of the simulator and for generally enhancing the quality and performance of the simulator.

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A method for fast colour and geometric correction of a tiled display system is presented in this paper. Such kind of displays are a common choice for virtual reality applications and simulators, where a high resolution image is required. They are the cheapest and more flexible alternative for large image generation but they require a precise geometric and colour correction. The purpose of the proposed method is to correct the projection system as fast as possible so in case the system needs to be recalibrated it doesn’t interfere with the normal operation of the simulator or virtual reality application. This technique makes use of a single conventional webcam for both geometric and photometric correction. Some previous assumptions are made, like planar projection surface and negligibleintra-projector colour variation and black-offset levels. If these assumptions hold true, geometric and photometric seamlessness can be achievedfor this kind of display systems. The method described in this paper is scalable for an undefined number of projectors and completely automatic.

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Systems of Systems (SoS) present challenging features and existing tools result often inadequate for their analysis, especially for heteregeneous networked infrastructures. Most accident scenarios in networked systems cannot be addressed by a simplistic black or white (i.e. functioning or failed) approach. Slow deviations from nominal operation conditions may cause degraded behaviours that suddenly end up into unexpected malfunctioning, with large portions of the network affected. In this paper,we present a language for modelling networked SoS. The language makes it possible to represent interdependencies of various natures, e.g. technical, organizational and human. The representation of interdependencies is based on control relationships that exchange physical quantities and related information. The language also makes it possible the identification of accident scenarios, by representing the propagation of failure events throughout the network. The results can be used for assessing the effectiveness of those mechanisms and measures that contribute to the overall resilience, both in qualitative and quantitative terms. The presented modelling methodology is general enough to be applied in combination with already existing system analysis techniques, such as risk assessment, dependability and performance evaluation

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Se presenta un nuevo método de diseño conceptual en Ingeniería Aeronáutica basado el uso de modelos reducidos, también llamados modelos sustitutos (‘surrogates’). Los ingredientes de la función objetivo se calculan para cada indiviudo mediante la utilización de modelos sustitutos asociados a las distintas disciplinas técnicas que se construyen mediante definiciones de descomposición en valores singulares de alto orden (HOSVD) e interpolaciones unidimensionales. Estos modelos sustitutos se obtienen a partir de un número limitado de cálculos CFD. Los modelos sustitutos pueden combinarse, bien con un método de optimización global de tipo algoritmo genético, o con un método local de tipo gradiente. El método resultate es flexible a la par que mucho más eficiente, computacionalmente hablando, que los modelos convencionales basados en el cálculo directo de la función objetivo, especialmente si aparecen un gran número de parámetros de diseño y/o de modelado. El método se ilustra considerando una versión simplificada del diseño conceptual de un avión. Abstract An optimization method for conceptual design in Aeronautics is presented that is based on the use of surrogate models. The various ingredients in the target function are calculated for each individual using surrogates of the associated technical disciplines that are constructed via high order singular value decomposition and one dimensional interpolation. These surrogates result from a limited number of CFD calculated snapshots. The surrogates are combined with an optimization method, which can be either a global optimization method such as a genetic algorithm or a local optimization method, such as a gradient-like method. The resulting method is both flexible and much more computationally efficient than the conventional method based on direct calculation of the target function, especially if a large number of free design parameters and/or tunablemodeling parameters are present. The method is illustrated considering a simplified version of the conceptual design of an aircraft empennage.

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Runoff generation depends on rainfall, infiltration, interception, and surface depressional storage. Surface depressional storage depends on surface microtopography, usually quantified trough soil surface roughness (SSR). SSR is subject to spatial and temporal changes that create a high variability. In an agricultural environment, tillage operations produce abrupt changes in roughness. Subsequent rainfall gradually decreases roughness. Beside it, local variation in soil properties and hydrology cause its SSR to vary spatially at different scales. The methods commonly used to measure it involve collecting point elevations in regular grids using laser profilers or scanners, digital close range stereo-photogrammetry and terrestrial laser scanning or LIDAR systems. In this case, a laser-scanning instrument was used to obtain representative digital elevation models (DEMs) at a grid resolution of 7.2x7.2mm that cover an area of 0.9x0.9m. The DEMs were obtained from two study sites with different soils. The first study site was an experimental field on which five conventional tillage methods were applied. The second study site was a large olive orchard with trees planted at 7.5x5.0m and bare soils between rows. Here, three tillage treatments were applied. In this work we have evaluated the spatial variability of SSR at several scales studying differences in height calculated from points separated by incremental distances h were raised to power values q (from 0 to 4 in steps of 0.1). The q = 2 data were studied as a semivariogram model. The logarithm of average differences plotted vs. log h were characterized by their slope, ?(q). Structure functions [?(q) vs. q] were fitted showing that data had nonlinear structure functions typical of multiscale phenomena. Comparisson of the two types of soil in their respective structure functions are shown.

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Abstract Web 2.0 applications enabled users to classify information resources using their own vocabularies. The bottom-up nature of these user-generated classification systems have turned them into interesting knowledge sources, since they provide a rich terminology generated by potentially large user communities. Previous research has shown that it is possible to elicit some emergent semantics from the aggregation of individual classifications in these systems. However the generation of ontologies from them is still an open research problem. In this thesis we address the problem of how to tap into user-generated classification systems for building domain ontologies. Our objective is to design a method to develop domain ontologies from user-generated classifications systems. To do so, we rely on ontologies in the Web of Data to formalize the semantics of the knowledge collected from the classification system. Current ontology development methodologies have recognized the importance of reusing knowledge from existing resources. Thus, our work is framed within the NeOn methodology scenario for building ontologies by reusing and reengineering non-ontological resources. The main contributions of this work are: An integrated method to develop ontologies from user-generated classification systems. With this method we extract a domain terminology from the classification system and then we formalize the semantics of this terminology by reusing ontologies in the Web of Data. Identification and adaptation of existing techniques for implementing the activities in the method so that they can fulfill the requirements of each activity. A novel study about emerging semantics in user-generated lists. Resumen La web 2.0 permitió a los usuarios clasificar recursos de información usando su propio vocabulario. Estos sistemas de clasificación generados por usuarios son recursos interesantes para la extracción de conocimiento debido principalmente a que proveen una extensa terminología generada por grandes comunidades de usuarios. Se ha demostrado en investigaciones previas que es posible obtener una semántica emergente de estos sistemas. Sin embargo la generación de ontologías a partir de ellos es todavía un problema de investigación abierto. Esta tesis trata el problema de cómo aprovechar los sistemas de clasificación generados por usuarios en la construcción de ontologías de dominio. Así el objetivo de la tesis es diseñar un método para desarrollar ontologías de dominio a partir de sistemas de clasificación generados por usuarios. El método propuesto reutiliza conceptualizaciones existentes en ontologías publicadas en la Web de Datos para formalizar la semántica del conocimiento que se extrae del sistema de clasificación. Por tanto, este trabajo está enmarcado dentro del escenario para desarrollar ontologías mediante la reutilización y reingeniería de recursos no ontológicos que se ha definido en la Metodología NeOn. Las principales contribuciones de este trabajo son: Un método integrado para desarrollar una ontología de dominio a partir de sistemas de clasificación generados por usuarios. En este método se extrae una terminología de dominio del sistema de clasificación y posteriormente se formaliza su semántica reutilizando ontologías en la Web de Datos. La identificación y adaptación de un conjunto de técnicas para implementar las actividades propuestas en el método de tal manera que puedan cumplir automáticamente los requerimientos de cada actividad. Un novedoso estudio acerca de la semántica emergente en las listas generadas por usuarios en la Web.