Application of overlay techniques to network monitoring

Measurement and monitoring are important for correct and efficient operation of a network, since these activities provide reliable information and accurate analysis for characterizing and troubleshooting a network’s performance. The focus of network measurement is to measure the volume and types of traffic on a particular network and to record the raw measurement results. The focus of network monitoring is to initiate measurement tasks, collect raw measurement results, and report aggregated outcomes. Network systems are continuously evolving: besides incremental change to accommodate new devices, more drastic changes occur to accommodate new applications, such as overlay-based content delivery networks. As a consequence, a network can experience significant increases in size and significant levels of long-range, coordinated, distributed activity; furthermore, heterogeneous network technologies, services and applications coexist and interact. Reliance upon traditional, point-to-point, ad hoc measurements to manage such networks is becoming increasingly tenuous. In particular, correlated, simultaneous 1-way measurements are needed, as is the ability to access measurement information stored throughout the network of interest. To address these new challenges, this dissertation proposes OverMon, a new paradigm for edge-to-edge network monitoring systems through the application of overlay techniques. Of particular interest, the problem of significant network overheads caused by normal overlay network techniques has been addressed by constructing overlay networks with topology awareness - the network topology information is derived from interior gateway protocol (IGP) traffic, i.e. OSPF traffic, thus eliminating all overlay maintenance network overhead. Through a prototype that uses overlays to initiate measurement tasks and to retrieve measurement results, systematic evaluation has been conducted to demonstrate the feasibility and functionality of OverMon. The measurement results show that OverMon achieves good performance in scalability, flexibility and extensibility, which are important in addressing the new challenges arising from network system evolution. This work, therefore, contributes an innovative approach of applying overly techniques to solve realistic network monitoring problems, and provides valuable first hand experience in building and evaluating such a distributed system

CLASH: A Protocol for Internet-Scale Utility-Oriented Distributed Computing

Distributed Hash Table (DHT) overlay networks offer an efficient and robust technique for wire-area data storage and queries. Workload from real applications that use DHT networks will likely exhibit significant skews that can result in bottlenecks and failures that limit the overall scalability of the DHT approach. In this paper we present the Content and Load-Aware Scalable Hashing (CLASH) protocol that can enhance the load distribution behavior of a DHT. CLASH relies on a variable-length identifier key scheme, where the length of any individual key is a function of load. CLASH uses variable-length keys to cluster content-related objects on single nodes to achieve processing efficiencies, and minimally disperse objects across multiple servers when hotspots occur. We demonstrate the performance benefits of CLASH through analysis and simulation. 1

Ami-deu : un cadre sémantique pour des applications adaptables dans des environnements intelligents

Cette thèse vise à étendre l’utilisation de l'Internet des objets (IdO) en facilitant le développement d’applications par des personnes non experts en développement logiciel. La thèse propose une nouvelle approche pour augmenter la sémantique des applications d’IdO et l’implication des experts du domaine dans le développement d’applications sensibles au contexte. Notre approche permet de gérer le contexte changeant de l’environnement et de générer des applications qui s’exécutent dans plusieurs environnements intelligents pour fournir des actions requises dans divers contextes. Notre approche est mise en œuvre dans un cadriciel (AmI-DEU) qui inclut les composants pour le développement d’applications IdO. AmI-DEU intègre les services d’environnement, favorise l’interaction de l’utilisateur et fournit les moyens de représenter le domaine d’application, le profil de l’utilisateur et les intentions de l’utilisateur. Le cadriciel permet la définition d’applications IoT avec une intention d’activité autodécrite qui contient les connaissances requises pour réaliser l’activité. Ensuite, le cadriciel génère Intention as a Context (IaaC), qui comprend une intention d’activité autodécrite avec des connaissances colligées à évaluer pour une meilleure adaptation dans des environnements intelligents. La sémantique de l’AmI-DEU est basée sur celle du ContextAA (Context-Aware Agents) – une plateforme pour fournir une connaissance du contexte dans plusieurs environnements. Le cadriciel effectue une compilation des connaissances par des règles et l'appariement sémantique pour produire des applications IdO autonomes capables de s’exécuter en ContextAA. AmI- DEU inclut également un outil de développement visuel pour le développement et le déploiement rapide d'applications sur ContextAA. L'interface graphique d’AmI-DEU adopte la métaphore du flux avec des aides visuelles pour simplifier le développement d'applications en permettant des définitions de règles étape par étape. Dans le cadre de l’expérimentation, AmI-DEU comprend un banc d’essai pour le développement d’applications IdO. Les résultats expérimentaux montrent une optimisation sémantique potentielle des ressources pour les applications IoT dynamiques dans les maisons intelligentes et les villes intelligentes. Notre approche favorise l'adoption de la technologie pour améliorer le bienêtre et la qualité de vie des personnes. Cette thèse se termine par des orientations de recherche que le cadriciel AmI-DEU dévoile pour réaliser des environnements intelligents omniprésents fournissant des adaptations appropriées pour soutenir les intentions des personnes.Abstract: This thesis aims at expanding the use of the Internet of Things (IoT) by facilitating the development of applications by people who are not experts in software development. The thesis proposes a new approach to augment IoT applications’ semantics and domain expert involvement in context-aware application development. Our approach enables us to manage the changing environment context and generate applications that run in multiple smart environments to provide required actions in diverse settings. Our approach is implemented in a framework (AmI-DEU) that includes the components for IoT application development. AmI- DEU integrates environment services, promotes end-user interaction, and provides the means to represent the application domain, end-user profile, and end-user intentions. The framework enables the definition of IoT applications with a self-described activity intention that contains the required knowledge to achieve the activity. Then, the framework generates Intention as a Context (IaaC), which includes a self-described activity intention with compiled knowledge to be assessed for augmented adaptations in smart environments. AmI-DEU framework semantics adopts ContextAA (Context-Aware Agents) – a platform to provide context-awareness in multiple environments. The framework performs a knowledge compilation by rules and semantic matching to produce autonomic IoT applications to run in ContextAA. AmI-DEU also includes a visual tool for quick application development and deployment to ContextAA. The AmI-DEU GUI adopts the flow metaphor with visual aids to simplify developing applications by allowing step-by-step rule definitions. As part of the experimentation, AmI-DEU includes a testbed for IoT application development. Experimental results show a potential semantic optimization for dynamic IoT applications in smart homes and smart cities. Our approach promotes technology adoption to improve people’s well-being and quality of life. This thesis concludes with research directions that the AmI-DEU framework uncovers to achieve pervasive smart environments providing suitable adaptations to support people’s intentions

Proceedings of the Seventh Italian Conference on Computational Linguistics CLiC-it 2020

On behalf of the Program Committee, a very warm welcome to the Seventh Italian Conference on Computational Linguistics (CLiC-it 2020). This edition of the conference is held in Bologna and organised by the University of Bologna. The CLiC-it conference series is an initiative of the Italian Association for Computational Linguistics (AILC) which, after six years of activity, has clearly established itself as the premier national forum for research and development in the fields of Computational Linguistics and Natural Language Processing, where leading researchers and practitioners from academia and industry meet to share their research results, experiences, and challenges

XATA 2005: XML: aplicações e tecnologias associadas

Esta é a terceira conferência sobre a temática do XML, que tenta reunir anualmente a comunidade XML portuguesa. Olhando para o passado, e estudando o que aconteceu, podemos observar uma evolução interessante. Na primeira conferência (2003), houve uma vintena de trabalhos submetidos, maioritariamente da autoria ou da supervisão dos membros que integravam a comissão organizadora. Na segunda conferência (2004), houve uma participação mais forte da comunidade portuguesa mas ainda com números pouco expressivos. Nesta altura, apostou-se também numa forte participação da indústria, o que se traduziu num conjunto apreciável de apresentações de casos reais. Nesta terceira edição, a participação excedeu as nossas expectativas. Houve uma forte adesão nacional e internacional (Espanha e Brasil, o que para um evento onde se pretende privilegiar a língua portuguesa é ainda mais significativo). A distribuição geográfica em Portugal também aumentou, havendo mais instituições participantes. Se analisarmos as temáticas, abordadas nas três conferências, percebemos que também aqui há uma evolução no sentido de uma maior maturidade. Enquanto que no primeiro encontro, os trabalhos abordavam problemas emergentes na utilização da tecnologia, no segundo encontro a grande incidência foi nos Web Services, uma nova tecnologia baseada em XML e, no terceiro, a maior incidência é na construção de repositórios, motores de pesquisa e linguagens de interrogação. Isto poderá revelar que, de certa forma, os investigadores e os utilizadores já dominam bem a tecnologia, já têm as sua linhas de produção documental em XML e que agora é chegado o momento de armazenar aquela informação em repositórios e de a utilizar a partir deles. Se reflectirmos um pouco sobre o ciclo de vida documental, podemos concluir que o armazenamento aparece como uma das últimas fases. Por isso, podemos dizer que a comunidade portuguesa de XML "está a fechar" o ciclo de desenvolvimento documental XML. Nesta edição, houve um elevado número de submissões o que levou a uma sobrecarga de trabalho por parte dos revisores. Estes conseguiram desempenhar bem o seu papel e cumprir as datas definidas pelo "chair". Mas o que aconteceu fez-nos pensar que há necessidade de alargar ainda mais a Comissão Científica. Como consequência do número elevado de submissões houve algumas rejeições. Aos respectivos autores, fica aqui expresso um voto para que melhorem os respectivos trabalhos e de que esperamos ter contribuído para isso com os relatórios de revisão que foram enviados.Microsoft Portuga

Towards a Semantics-based Framework for KD- and IR-style Resource Querying on XML-based P2P Information Systems

1no-nonenoneCUZZOCREA ACuzzocrea, Alfredo Massimilian

Security Enhanced Applications for Information Systems

Every day, more users access services and electronically transmit information which is usually disseminated over insecure networks and processed by websites and databases, which lack proper security protection mechanisms and tools. This may have an impact on both the users’ trust as well as the reputation of the system’s stakeholders. Designing and implementing security enhanced systems is of vital importance. Therefore, this book aims to present a number of innovative security enhanced applications. It is titled “Security Enhanced Applications for Information Systems” and includes 11 chapters. This book is a quality guide for teaching purposes as well as for young researchers since it presents leading innovative contributions on security enhanced applications on various Information Systems. It involves cases based on the standalone, network and Cloud environments

Pseudo-contractions as Gentle Repairs

Updating a knowledge base to remove an unwanted consequence is a challenging task. Some of the original sentences must be either deleted or weakened in such a way that the sentence to be removed is no longer entailed by the resulting set. On the other hand, it is desirable that the existing knowledge be preserved as much as possible, minimising the loss of information. Several approaches to this problem can be found in the literature. In particular, when the knowledge is represented by an ontology, two different families of frameworks have been developed in the literature in the past decades with numerous ideas in common but with little interaction between the communities: applications of AGM-like Belief Change and justification-based Ontology Repair. In this paper, we investigate the relationship between pseudo-contraction operations and gentle repairs. Both aim to avoid the complete deletion of sentences when replacing them with weaker versions is enough to prevent the entailment of the unwanted formula. We show the correspondence between concepts on both sides and investigate under which conditions they are equivalent. Furthermore, we propose a unified notation for the two approaches, which might contribute to the integration of the two areas