73 research outputs found

    Hierarchical categorisation of tags for delicious

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    In the scenario of social bookmarking, a user browsing the Web bookmarks web pages and assigns free-text labels (i.e., tags) to them according to their personal preferences. In this technical report, we approach one of the practical aspects when it comes to represent users' interests from their tagging activity, namely the categorization of tags into high-level categories of interest. The reason is that the representation of user profiles on the basis of the myriad of tags available on the Web is certainly unfeasible from various practical perspectives; mainly concerning the unavailability of data to reliably, accurately measure interests across such fine-grained categorisation, and, should the data be available, its overwhelming computational intractability. Motivated by this, our study presents the results of a categorization process whereby a collection of tags posted at Delicious #http://delicious.com# are classified into 200 subcategories of interest.Preprin

    Hierarchical categorisation of web tags for Delicious

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    In the scenario of social bookmarking, a user browsing the Web bookmarks web pages and assigns free-text labels (i.e., tags) to them according to their personal preferences. The benefits of social tagging are clear – tags enhance Web content browsing and search. However, since these tags may be publicly available to any Internet user, a privacy attacker may collect this information and extract an accurate snapshot of users’ interests or user profiles, containing sensitive information, such as health-related information, political preferences, salary or religion. In order to hinder attackers in their efforts to profile users, this report focuses on the practical aspects of capturing user interests from their tagging activity. More accurately, we study how to categorise a collection of tags posted by users in one of the most popular bookmarking services, Delicious (http://delicious.com).Preprin

    Command and Control Systems for Search and Rescue Robots

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    The novel application of unmanned systems in the domain of humanitarian Search and Rescue (SAR) operations has created a need to develop specific multi-Robot Command and Control (RC2) systems. This societal application of robotics requires human-robot interfaces for controlling a large fleet of heterogeneous robots deployed in multiple domains of operation (ground, aerial and marine). This chapter provides an overview of the Command, Control and Intelligence (C2I) system developed within the scope of Integrated Components for Assisted Rescue and Unmanned Search operations (ICARUS). The life cycle of the system begins with a description of use cases and the deployment scenarios in collaboration with SAR teams as end-users. This is followed by an illustration of the system design and architecture, core technologies used in implementing the C2I, iterative integration phases with field deployments for evaluating and improving the system. The main subcomponents consist of a central Mission Planning and Coordination System (MPCS), field Robot Command and Control (RC2) subsystems with a portable force-feedback exoskeleton interface for robot arm tele-manipulation and field mobile devices. The distribution of these C2I subsystems with their communication links for unmanned SAR operations is described in detail. Field demonstrations of the C2I system with SAR personnel assisted by unmanned systems provide an outlook for implementing such systems into mainstream SAR operations in the future

    Internet of Things From Hype to Reality

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    The Internet of Things (IoT) has gained significant mindshare, let alone attention, in academia and the industry especially over the past few years. The reasons behind this interest are the potential capabilities that IoT promises to offer. On the personal level, it paints a picture of a future world where all the things in our ambient environment are connected to the Internet and seamlessly communicate with each other to operate intelligently. The ultimate goal is to enable objects around us to efficiently sense our surroundings, inexpensively communicate, and ultimately create a better environment for us: one where everyday objects act based on what we need and like without explicit instructions

    Software Defined Application Delivery Networking

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    In this thesis we present the architecture, design, and prototype implementation details of AppFabric. AppFabric is a next generation application delivery platform for easily creating, managing and controlling massively distributed and very dynamic application deployments that may span multiple datacenters. Over the last few years, the need for more flexibility, finer control, and automatic management of large (and messy) datacenters has stimulated technologies for virtualizing the infrastructure components and placing them under software-based management and control; generically called Software-defined Infrastructure (SDI). However, current applications are not designed to leverage this dynamism and flexibility offered by SDI and they mostly depend on a mix of different techniques including manual configuration, specialized appliances (middleboxes), and (mostly) proprietary middleware solutions together with a team of extremely conscientious and talented system engineers to get their applications deployed and running. AppFabric, 1) automates the whole control and management stack of application deployment and delivery, 2) allows application architects to define logical workflows consisting of application servers, message-level middleboxes, packet-level middleboxes and network services (both, local and wide-area) composed over application-level routing policies, and 3) provides the abstraction of an application cloud that allows the application to dynamically (and automatically) expand and shrink its distributed footprint across multiple geographically distributed datacenters operated by different cloud providers. The architecture consists of a hierarchical control plane system called Lighthouse and a fully distributed data plane design (with no special hardware components such as service orchestrators, load balancers, message brokers, etc.) called OpenADN . The current implementation (under active development) consists of ~10000 lines of python and C code. AppFabric will allow applications to fully leverage the opportunities provided by modern virtualized Software-Defined Infrastructures. It will serve as the platform for deploying massively distributed, and extremely dynamic next generation application use-cases, including: Internet-of-Things/Cyber-Physical Systems: Through support for managing distributed gather-aggregate topologies common to most Internet-of-Things(IoT) and Cyber-Physical Systems(CPS) use-cases. By their very nature, IoT and CPS use cases are massively distributed and have different levels of computation and storage requirements at different locations. Also, they have variable latency requirements for their different distributed sites. Some services, such as device controllers, in an Iot/CPS application workflow may need to gather, process and forward data under near-real time constraints and hence need to be as close to the device as possible. Other services may need more computation to process aggregated data to drive long term business intelligence functions. AppFabric has been designed to provide support for such very dynamic, highly diversified and massively distributed application use-cases. Network Function Virtualization: Through support for heterogeneous workflows, application-aware networking, and network-aware application deployments, AppFabric will enable new partnerships between Application Service Providers (ASPs) and Network Service Providers (NSPs). An application workflow in AppFabric may comprise of application services, packet and message-level middleboxes, and network transport services chained together over an application-level routing substrate. The Application-level routing substrate allows policy-based service chaining where the application may specify policies for routing their application traffic over different services based on application-level content or context. Virtual worlds/multiplayer games: Through support for creating, managing and controlling dynamic and distributed application clouds needed by these applications. AppFabric allows the application to easily specify policies to dynamically grow and shrink the application\u27s footprint over different geographical sites, on-demand. Mobile Apps: Through support for extremely diversified and very dynamic application contexts typical of such applications. Also, AppFabric provides support for automatically managing massively distributed service deployment and controlling application traffic based on application-level policies. This allows mobile applications to provide the best Quality-of-Experience to its users without This thesis is the first to handle and provide a complete solution for such a complex and relevant architectural problem that is expected to touch each of our lives by enabling exciting new application use-cases that are not possible today. Also, AppFabric is a non-proprietary platform that is expected to spawn lots of innovations both in the design of the platform itself and the features it provides to applications. AppFabric still needs many iterations, both in terms of design and implementation maturity. This thesis is not the end of journey for AppFabric but rather just the beginning

    On the scalability of LISP and advanced overlaid services

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    In just four decades the Internet has gone from a lab experiment to a worldwide, business critical infrastructure that caters to the communication needs of almost a half of the Earth's population. With these figures on its side, arguing against the Internet's scalability would seem rather unwise. However, the Internet's organic growth is far from finished and, as billions of new devices are expected to be joined in the not so distant future, scalability, or lack thereof, is commonly believed to be the Internet's biggest problem. While consensus on the exact form of the solution is yet to be found, the need for a semantic decoupling of a node's location and identity, often called a location/identity separation, is generally accepted as a promising way forward. Typically, this requires the introduction of new network elements that provide the binding of the two names-paces and caches that avoid hampering router packet forwarding speeds. But due to this increased complexity the solution's scalability is itself questioned. This dissertation evaluates the suitability of using the Locator/ID Separation Protocol (LISP), one of the most successful proposals to follow the location/identity separation guideline, as a solution to the Internet's scalability problem. However, because the deployment of any new architecture depends not only on solving the incumbent's technical problems but also on the added value that it brings, our approach follows two lines. In the first part of the thesis, we develop the analytical tools to evaluate LISP's control plane scalability while in the second we show that the required control/data plane separation provides important benefits that could drive LISP's adoption. As a first step to evaluating LISP's scalability, we propose a methodology for an analytical analysis of cache performance that relies on the working-set theory to estimate traffic locality of reference. One of our main contribution is that we identify the conditions network traffic must comply with for the theory to be applicable and then use the result to develop a model that predicts average cache miss rates. Furthermore, we study the model's suitability for long term cache provisioning and assess the cache's vulnerability in front of malicious users through an extension that accounts for cache polluting traffic. As a last step, we investigate the main sources of locality and their impact on the asymptotic scalability of the LISP cache. An important finding here is that destination popularity distribution can accurately describe cache performance, independent of the much harder to model short term correlations. Under a small set of assumptions, this result finally enables us to characterize asymptotic scalability with respect to the amount of prefixes (Internet growth) and users (growth of the LISP site). We validate the models and discuss the accuracy of our assumptions using several one-day-long packet traces collected at the egress points of a campus and an academic network. To show the added benefits that could drive LISP's adoption, in the second part of the thesis we investigate the possibilities of performing inter-domain multicast and improving intra-domain routing. Although the idea of using overlaid services to improve underlay performance is not new, this dissertation argues that LISP offers the right tools to reliably and easily implement such services due to its reliance on network instead of application layer support. In particular, we present and extensively evaluate Lcast, a network-layer single-source multicast framework designed to merge the robustness and efficiency of IP multicast with the configurability and low deployment cost of application-layer overlays. Additionally, we describe and evaluate LISP-MPS, an architecture capable of exploiting LISP to minimize intra-domain routing tables and ensure, among other, support for multi protocol switching and virtual networks.En menos de cuatro dĂ©cadas Internet ha evolucionado desde un experimento de laboratorio hasta una infraestructura de alcance mundial, de importancia crĂ­tica para negocios y que atiende a las necesidades de casi un tercio de los habitantes del planeta. Con estos nĂșmeros, es difĂ­cil tratar de negar la necesidad de escalabilidad de Internet. Sin embargo, el crecimiento orgĂĄnico de Internet estĂĄ aĂșn lejos de finalizar ya que se espera que mil millones de dispositivos nuevos se conecten en el futuro cercano. AsĂ­ pues, la falta de escalabilidad es el mayor problema al que se enfrenta Internet hoy en dĂ­a. Aunque la soluciĂłn definitiva al problema estĂĄ aĂșn por definir, la necesidad de desacoplar semĂĄnticamente la localizaciĂłn e identidad de un nodo, a menudo llamada locator/identifier separation, es generalmente aceptada como un camino prometedor a seguir. Sin embargo, esto requiere la introducciĂłn de nuevos dispositivos en la red que unan los dos espacios de nombres disjuntos resultantes y de cachĂ©s que almacenen los enlaces temporales entre ellos con el fin de aumentar la velocidad de transmisiĂłn de los enrutadores. A raĂ­z de esta complejidad añadida, la escalabilidad de la soluciĂłn en si misma es tambiĂ©n cuestionada. Este trabajo evalĂșa la idoneidad de utilizar Locator/ID Separation Protocol (LISP), una de las propuestas mĂĄs exitosas que siguen la pauta locator/identity separation, como una soluciĂłn para la escalabilidad de la Internet. Con tal fin, desarrollamos las herramientas analĂ­ticas para evaluar la escalabilidad del plano de control de LISP pero tambiĂ©n para mostrar que la separaciĂłn de los planos de control y datos proporciona un importante valor añadido que podrĂ­a impulsar la adopciĂłn de LISP. Como primer paso para evaluar la escalabilidad de LISP, proponemos una metodologĂ­a para un estudio analĂ­tico del rendimiento de la cachĂ© que se basa en la teorĂ­a del working-set para estimar la localidad de referencias. Identificamos las condiciones que el trĂĄfico de red debe cumplir para que la teorĂ­a sea aplicable y luego desarrollamos un modelo que predice las tasas medias de fallos de cachĂ© con respecto a parĂĄmetros de trĂĄfico fĂĄcilmente medibles. Por otra parte, para demostrar su versatilidad y para evaluar la vulnerabilidad de la cachĂ© frente a usuarios malintencionados, extendemos el modelo para considerar el rendimiento frente a trĂĄfico generado por usuarios maliciosos. Como Ășltimo paso, investigamos como usar la popularidad de los destinos para estimar el rendimiento de la cachĂ©, independientemente de las correlaciones a corto plazo. Bajo un pequeño conjunto de hipĂłtesis conseguimos caracterizar la escalabilidad con respecto a la cantidad de prefijos (el crecimiento de Internet) y los usuarios (crecimiento del sitio LISP). Validamos los modelos y discutimos la exactitud de nuestras suposiciones utilizando varias trazas de paquetes reales. Para mostrar los beneficios adicionales que podrĂ­an impulsar la adopciĂłn de LISP, tambiĂ©n investigamos las posibilidades de realizar multidifusiĂłn inter-dominio y la mejora del enrutamiento dentro del dominio. Aunque la idea de utilizar servicios superpuestos para mejorar el rendimiento de la capa subyacente no es nueva, esta tesis sostiene que LISP ofrece las herramientas adecuadas para poner en prĂĄctica de forma fiable y fĂĄcilmente este tipo de servicios debido a que LISP actĂșa en la capa de red y no en la capa de aplicaciĂłn. En particular, presentamos y evaluamos extensamente Lcast, un marco de multidifusiĂłn con una sola fuente diseñado para combinar la robustez y eficiencia de la multidifusiĂłn IP con la capacidad de configuraciĂłn y bajo coste de implementaciĂłn de una capa superpuesta a nivel de aplicaciĂłn. AdemĂĄs, describimos y evaluamos LISP-MPS, una arquitectura capaz de explotar LISP para minimizar las tablas de enrutamiento intra-dominio y garantizar, entre otras, soporte para conmutaciĂłn multi-protocolo y redes virtuales

    Hierarchical network topographical routing

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    Within the last 10 years the content consumption model that underlies many of the assumptions about traffic aggregation within the Internet has changed; the previous short burst transfer followed by longer periods of inactivity that allowed for statistical aggregation of traffic has been increasingly replaced by continuous data transfer models. Approaching this issue from a clean slate perspective; this work looks at the design of a network routing structure and supporting protocols for assisting in the delivery of large scale content services. Rather than approaching a content support model through existing IP models the work takes a fresh look at Internet routing through a hierarchical model in order to highlight the benefits that can be gained with a new structural Internet or through similar modifications to the existing IP model. The work is divided into three major sections: investigating the existing UK based Internet structure as compared to the traditional Autonomous System (AS) Internet structural model; a localised hierarchical network topographical routing model; and intelligent distributed localised service models. The work begins by looking at the United Kingdom (UK) Internet structure as an example of a current generation technical and economic model with shared access to the last mile connectivity and a large scale wholesale network between Internet Service Providers (ISPs) and the end user. This model combined with the Internet Protocol (IP) address allocation and transparency of the wholesale network results in an enforced inefficiency within the overall network restricting the ability of ISPs to collaborate. From this model a core / edge separation hierarchical virtual tree based routing protocol based on the physical network topography (layers 2 and 3) is developed to remove this enforced inefficiency by allowing direct management and control at the lowest levels of the network. This model acts as the base layer for further distributed intelligent services such as management and content delivery to enable both ISPs and third parties to actively collaborate and provide content from the most efficient source

    Techniques d'ingénierie de trafic dynamique pour l'internet

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    Network convergence and new applications running on end-hosts result in increasingly variable and unpredictable traffic patterns. By providing origin-destination pairs with several possible paths, Dynamic Load-Balancing (DLB) has proved itself an excellent tool to face this uncertainty. The objective in DLB is to distribute traffic among these paths in real-time so that a certain objective function is optimized. In these dynamic schemes, paths are established a priori and the amount of traffic sent through each of them depends on the current traffic demand and network condition. In this thesis we study and propose various DLB mechanisms, differing in two important aspects. The first difference resides in the assumption, or not, that resources are reserved for each path. The second lies on the objective function, which clearly dictates the performance obtained from the network. However, a performance benchmarking of the possible choices has not been carried out so far. In this sense, for the case in which no reservations are performed, we study and compare several objective functions, including a proposal of ours. We will also propose and study a new distributed algorithm to attain the optimum of these objective functions. Its advantage with respect to previous proposals is its complete self-configuration (i. E. Convergence is guaranteed without any parametrization). Finally, we present the first complete comparative study between DLB and Robust Routing (a fixed routing configuration for all possible traffic demands). In particular, we analyze which scheme is more convenient in each given situation, and highlight some of their respective shortcomings and virtues.Avec la multiplication des services dans un mĂȘme rĂ©seau et les diversitĂ©s des applications utilisĂ©es par les usagers finaux, le trafic transportĂ© est devenu trĂšs complexe et dynamique. Le Partage de la Charge Dynamique (PCD) constitue une alternative intĂ©ressante pour rĂ©soudre cette problĂ©matique. Si une paire Source-Destination est connectĂ©e par plusieurs chemins, le problĂšme est le suivant : comment distribuer le trafic parmi ces chemins de telle façon qu’une fonction objective soit optimisĂ©. Dans ce cas les chemins sont fixĂ©s a priori et la quantitĂ© de trafic acheminĂ©e sur chaque route est dĂ©terminĂ©e dynamiquement en fonction de la demande de trafic et de la situation actuelle du rĂ©seau. Dans cette thĂšse nous Ă©tudions puis nous proposons plusieurs mĂ©canismes de PCD. Tout d'abord, nous distinguons deux types d’architecture : celles dans lesquelles les ressources sont rĂ©servĂ©es pour chaque chemin, et celles pour lesquelles aucune rĂ©servation n'est effectuĂ©e. La simplification faite dans le premier type d’architecture nous permet de proposer l'utilisation d'un nouveau mĂ©canisme pour gĂ©rer les chemins. Partant de ce mĂ©canisme, nous dĂ©finissons un nouvel algorithme de PCD. Concernant la deuxiĂšme architecture, nous Ă©tudions et comparons plusieurs fonctions objectives. À partir de notre Ă©tude, nous proposons un nouvel algorithme distribuĂ© permettant d’atteindre l'optimum de ces fonctions objectives. La principale caractĂ©ristique de notre algorithme, et son avantage par rapport aux propositions antĂ©rieures, est sa capacitĂ© d'auto-configuration, dans la mesure oĂč la convergence de l'algorithme est garantie sans aucun besoin de rĂ©glage prĂ©alable de ses paramĂštres

    Distributed control of reconfigurable mobile network agents for resource coordination

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    Includes abstract.Includes bibliographical references.Considering the tremendous growth of internet applications and network resource federation proposed towards future open access network (FOAN), the need to analyze the robustness of the classical signalling mechanisms across multiple network operators cannot be over-emphasized. It is envisaged, there will be additional challenges in meeting the bandwidth requirements and network management...The first objective of this project is to describe the networking environment based on the support for heterogeneity of network components..
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