22 research outputs found
Routage et gestion de la mobilité dans les réseaux personnels
L'objectif de cette thèse est d'étudier des méthodes et des stratégies efficaces pour le routage et la gestion de la mobilité dans le cadre des réseaux personnels. Dans un premier temps, nous proposons le cadre de nos études: Personal Ubiquitous Environments (PUE). Un PUE est constitué d'un ensemble d'utilisateurs ayant des terminaux disposant d'interfaces réseau hétérogènes, et dont l'objectif est de mettre en oeuvre des mécanismes de coopération et de partage des ressources de manière totalement distribuée. Dans ce cadre, la thèse a proposé des solutions innovantes contribuant à améliorer la communication inter et intra réseau personnels. La première contribution porte sur le protocole PNRP (Personal Network Routing Protocol) dont le but est de développer un routage à base de politiques (policy-based routing) pour les environnements personnels. La seconde, intitulée ADD (Adaptive Distributed gateway Discovery), est un mécanisme totalement distribué pour la découverte de multiples chemins vers une passerelle vers un réseau opéré. De plus, étant donné que ces environnements sont hétérogènes par leurs compositions (réseaux d'accès, terminaux ...), une architecture de gestion de la mobilité qui permet une gestion unifiée de la localisation et de la mobilité sans coutures appliquant lénsemble des noeuds a également été traitée. Les résultats d'évaluation par simulation démontrent l'applicabilité et léfficacité des ces protocoles.The aim of this thesis is to investigate methods and strategies for efficient routing and mobility management in personal environments. The concept of Personal Ubiquitous Environments (PUE) is introduced which accommodates heterogeneous devices and access networks of different users and sustain the notion of sharing resources in a distributed manner. A prerequisite for achieving the resource (devices, networks) sharing in personal environments is the deployment of suitable communication protocols which establish efficient multi-hop routes betweens the devices of the PUE. Personal Network Routing Protocol (PNRP) has been developed to perform policy-based routing in personal environments. Moreover, in certain personal networking scenarios, the infrastructure network components (i.e. gateways) are more than one-hop distance from the user's devices; Adaptive Distributed gateway Discovery (ADD) protocol is thereby proposed to efficiently discover the multi-hop routes towards the gateway in a totally distributed manner. All the more, since the personal environments regroups heterogeneous access networks, an efficient mobility management architecture is proposed which offers unified location management and seamless handover experience to dynamic personal nodes. The proposed protocols are assessed by means of numerous communication scenarios; the simulation results demonstrate the applicability of the proposed protocols
Art and transgression in Edgar Wind : A study on the conceptual armature and reception of Art and anarchy (1963)
Orientador: Luiz Cesar Marques FilhoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências HumanasResumo: Esta dissertação tem por objeto a obra Art and Anarchy, publicada em 1963, da autoria de Edgar Wind (1900-1971), intelectual alemão radicado nos Estados Unidos e posteriormente no Reino Unido, cuja carreira intelectual trafegou entre as áreas da epistemologia, estética, história da arte e da cultura. O livro ¿ resultado de um ciclo de seis conferências de trinta minutos realizadas para a rádio BBC em 1960 nas anuais Reith Lectures ¿ trata da relação entre a arte e as forças anárquicas da imaginação humana em meados do século XX. Para este fim, avança-se uma crítica do pensamento artístico ocidental moderno a partir de uma análise das diversas forças históricas que o conformaram. Wind, que se notabilizou sobretudo por seus estudos sobre a arte do Renascimento italiano, retratística inglesa do Setecentos e filosofia da ciência, apresenta em Art and Anarchy uma visão multifacética da arte que lhe era contemporânea, cujo vigor crítico procede de seu ponto de vista heterodoxo: segundo ele, a experiência artística moderna resulta de um processo de marginalização em relação ao centro da vida humana que se origina no início do Oitocentos. Tal abordagem, inusual ou inexistente entre os estudiosos de sua geração que se ocuparam de questões atinentes à Tradição Clássica, é expressiva do amplo campo de interesses de Edgar Wind e de sua prática heurística essencialmente adisciplinar. A dissertação compõe-se dois eixos principais: (1) a tradução e notação de Art and Anarchy, objetivando tornar a obra acessível em português e explicitar para o leitor as numerosas referências implícitas do texto; (2) um estudo sobre a biografia intelectual de Edgar Wind, o contexto histórico da produção de suas Reith Lectures e a armadura conceitual de Art and Anarchy. Trata-se, portanto, de situar as análises da obra no âmbito das obras anteriores de Wind e de seu horizonte de erudição, de modo a avaliar em que medida essas conferências dialogam com as linhas mestras de seu pensamento ou oferecem, ao contrário, uma incursão tardia e relativamente isolada de seu discurso críticoAbstract: This thesis has as its main object the book Art and Anarchy, published in 1963 by Edgar Wind (1900-1971), a German intellectual expatriated to the United States and later to the United Kingdom, whose intellectual career navigated through the fields of epistemology, aesthetics, history of art and culture. The book ¿ the result of a cycle of six thirty minutes¿ conferences held for BBC radio in 1960 at the annual Reith Lectures ¿ deals with the relationship between art and the anarchic forces of the human imagination in the mid-20th century. To this end, a critique of modern Western artistic thought is advanced based on an analysis of the various historical forces that have shaped it. Wind, renowned for his studies on the art of the Italian Renaissance, English portraiture of the 17th century and philosophy of science, presents in Art and Anarchy a multifaceted view of the art of his lifetime, whose critical vigour stems from his heterodox point of view: according to him, the modern artistic experience results from a process of marginalization in relation to the centre of human life, a process whose origins he traces back to the beginning of the 18th century. Such an approach, unusual or non-existent among the scholars of his generation who dealt with matters pertaining to Classical Tradition, is expressive of Edgar Wind's broad field of interests and his essentially adisciplinary heuristic practice. This dissertation consists of two main axes: (1) the translation of Art and Anarchy into Portuguese and its notation, thus aiming to make the work accessible to the Portuguese-speaking world and to explain to the reader the numerous implicit references of the text; (2) a study of Edgar Wind's intellectual biography, the historical context of his Reith Lectures production, and the conceptual armour of Art and Anarchy. It is, therefore, necessary to situate the book in the framework of Wind's previous writings and in his intellectual horizon in order to evaluate to what extent these conferences dialogue with the main lines of his thought or offer, on the contrary, a late foray of his critical discourse, relatively isolatedMestradoHistoria da ArteMestre em História2014/21783-6FAPESPCNP
Edge Computing for Extreme Reliability and Scalability
The massive number of Internet of Things (IoT) devices and their continuous data collection will lead to a rapid increase in the scale of collected data. Processing all these collected data at the central cloud server is inefficient, and even is unfeasible or unnecessary. Hence, the task of processing the data is pushed to the network edges introducing the concept of Edge Computing. Processing the information closer to the source of data (e.g., on gateways and on edge micro-servers) not only reduces the huge workload of central cloud, also decreases the latency for real-time applications by avoiding the unreliable and unpredictable network latency to communicate with the central cloud
Quality management of surveillance multimedia streams via federated SDN controllers in Fiwi-iot integrated deployment environments
Traditionally, hybrid optical-wireless networks (Fiber-Wireless - FiWi domain) and last-mile Internet of Things edge networks (Edge IoT domain) have been considered independently, with no synergic management solutions. On the one hand, FiWi has primarily focused on high-bandwidth and low-latency access to cellular-equipped nodes. On the other hand, Edge IoT has mainly aimed at effective dispatching of sensor/actuator data among (possibly opportunistic) nodes, by using direct peer-to-peer and base station (BS)-assisted Internet communications. The paper originally proposes a model and an architecture that loosely federate FiWi and Edge IoT domains based on the interaction of FiWi and Edge IoT software defined networking controllers: The primary idea is that our federated controllers can seldom exchange monitoring data and control hints the one with the other, thus mutually enhancing their capability of end-to-end quality-aware packet management. To show the applicability and the effectiveness of the approach, our original proposal is applied to the notable example of multimedia stream provisioning from surveillance cameras deployed in the Edge IoT domain to both an infrastructure-side server and spontaneously interconnected mobile smartphones; our solution is able to tune the BS behavior of the FiWi domain and to reroute/prioritize traffic in the Edge IoT domain, with the final goal to reduce latency. In addition, the reported application case shows the capability of our solution of joint and coordinated exploitation of resources in FiWi and Edge IoT domains, with performance results that highlight its benefits in terms of efficiency and responsiveness
ANTMANET: a novel routing protocol for mobile ad-hoc networks based on ant colony optimisation
The core aim of this research is to present “ANTMANET” a novel routing protocol for Mobile Ad-Hoc networks. The proposed protocol aims to reduce the network overhead and delay introduced by node mobility in MANETs. There are two techniques embedded in this protocol, the “Local Zone” technique and the “North Neighbour” Table. They take an advantage of the fact that the nodes can obtain their location information by any means to reduce the network overhead during the route discovery phase and reduced the size of the routing table to guarantee faster convergence.
ANTMANET is a hybrid Ant Colony Optimisation-based (ACO) routing protocol. ACO is a Swarm Intelligence (SI) routing algorithm that is well known for its high-quality performance compared to other distributed routing algorithms such as Link State and Distance Vector.
ANTMANET has been benchmarked in various scenarios against the ACO routing protocol ANTHOCNET and several standard routing protocols including the Ad-Hoc On-Demand Distance Vector (AODV), Landmark Ad-Hoc Routing (LANMAR), and Dynamic MANET on Demand (DYMO). Performance metrics such as overhead, end-to-end delay, throughputs and jitter were used to evaluate ANTMANET performance. Experiments were performed using the QualNet simulator.
A benchmark test was conducted to evaluate the performance of an ANTMANET network against an ANTHOCNET network, with both protocols benchmarked against AODV as an established MANET protocol. ANTMANET has demonstrated a notable performance edge when the core algorithm has been optimised using the novel adaptation method that is proposed in this thesis. Based on the simulation results, the proposed protocol has shown 5% less End-to-End delay than ANTHOCNET. In regard to network overhead, the proposed protocol has shown 20% less overhead than ANTHOCNET. In terms of comparative throughputs ANTMANET in its finest performance has delivered 25% more packets than ANTHOCNET.
The overall validation results indicate that the proposed protocol was successful in reducing the network overhead and delay in high and low mobility speeds when compared with the AODV, DMO and LANMAR protocols. ANTMANET achieved at least a 45% less delay than AODV, 60% less delay than DYMO and 55% less delay than LANMAR. In terms of throughputs; ANTMANET in its best performance has delivered 35% more packets than AODV, 40% more than DYMO and 45% more than LANMAR. With respect to the network overhead results, ANTMANET has illustrated 65% less overhead than AODV, 70% less than DYMO and 60 % less than LANMAR. Regarding the Jitter, ANTMANET at its best has shown 60% less jitter than AODV, 55% jitter less than DYMO and 50% less jitter than LANMAR
A trading model and security regime for mobile e-commerce via ad hoc wireless networking
Ad hoc wireless networking offers mobile computer users the prospect of trading
with others in their vicinity anywhere anytime. This thesis explores the potential
for developing such trading applications. A notable difficulty in designing their
security services is being unable to use trusted parties. No one can be guaranteed
present in each ad hoc wireless network session. A side benefit is that their costs
don't have to be paid for.
A reference model is defined for ad hoc m-commerce and a threat model is for-
mulated of its security vulnerabilities. They are used to elicit security objectives
and requirements for such trading systems. Possible countermeasures to address
the threats are critically analysed and used to design security services to mitigate
them. They include a self-organised P2P identity support scheme using PGP cer-
tificates; a distributed reputation system backed by sanctions; a group membership
service based on membership vouchers, quorate decisions by some group members
and partial membership lists; and a security warning scheme.
Security analysis of the schemes shows that they can mitigate the threats to an
adequate degree to meet the trading system's security objectives and requirements
if users take due care when trading within it. Formal verification of the system
shows that it satisfies certain safety properties
CoMon: Cooperative Ambience Monitoring Platform with Continuity and Benefit Awareness
Mobile applications that sense continuously, such as location monitoring, are emerging. Despite their usefulness, their adoption in real-world deployment situations has been extremely slow. Many smartphone users are turned away by the drastic battery drain caused by continuous sensing and processing. Also, the extractable contexts from the phone are quite limited due to its position and sensing modalities. In this paper, we propose CoMon, a novel cooperative ambience monitoring platform, which newly addresses the energy problem through opportunistic cooperation among nearby mobile users. To maximize the benefit of cooperation, we develop two key techniques, (1) continuity-aware cooperator detection and (2) benefit-aware negotiation. The former employs heuristics to detect cooperators who will remain in the vicinity for a long period of time, while the latter automatically devises a cooperation plan that provides mutual benefit to cooperators, while considering running applications, available devices, and user policies. Through continuity- and benefit-aware operation, CoMon enables applications to monitor the environment at much lower energy consumption. We implement and deploy a CoMon prototype and show that it provides significant benefit for mobile sensing applications
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Easing software development for pervasive computing environments
textIn recent years pervasive computing has enjoyed an amazing growth in both research and commercial fields. Not only have the number of available techniques and tools expanded, but the number of actual deployments has been underwhelming. With this growth however, we are also experiencing a divergence of software interfaces, languages, and techniques. This leads to an understandably confusing landscape which needlessly burdens the development of applications. It is our sincere hope that through the use of specialized interfaces, languages, and tools, we can make pervasive computing environments more approachable and efficient to software developers and thereby increase the utility and value of pervasive computing applications. In this dissertation, we present a new method for creating and managing the long-term conversations between peers in pervasive computing environments. The Application Sessions Model formally describes these conversations and specifies techniques for managing them over their lifetimes. In addition to these descriptions, this dissertation presents a prototype implementation of the model and results from its use for realistic scenarios. To address the Application Sessions Model's unique needs for resource discovery in pervasive computing environments, we also present the Evolving Tuples Model. This model is also formally defined in this dissertation and practical examples are used to clarify its features. A prototype for both sensor hardware and software simulation of this model is described along with results characterizing the behavior of the model. The models, prototypes, and evaluations of both models presented here form the basis of a new and interesting line of research into support structures for pervasive computing application development.Electrical and Computer Engineerin
Designing to support impression management
This work investigates impression management and in particular impression management
using ubiquitous technology. Generally impression management is the process through
which people try to influence the impressions that others have about them. In particular,
impression management focuses on the flow of information between a performer and
his/her audience, with control over what is presented to whom being of the utmost
importance when trying to create the appropriate impression.
Ubiquitous technology has provided opportunities for individuals to present themselves to
others. However, the disconnection between presenter and audience over both time and
space can result in individuals being misrepresented. This thesis outlines two important
areas when trying to control the impression one gives namely, hiding and revealing, and
accountability. By exploring these two themes the continuous evolution and dynamic
nature of controlling the impression one gives is explored. While this ongoing adaptation is
recognised by designers they do not always create technology that is sufficiently dynamic
to support this process. As a result, this work attempts to answer three research questions:
RQ1: How do users of ubicomp systems appropriate recorded data from their everyday
activity and make it into a resource for expressing themselves to others in ways that are
dynamically tailored to their ongoing social context and audience?
RQ2: What technology can be built to support ubicomp system developers to design and
develop systems to support appropriation as a central part of a useful or enjoyable user
experience?
RQ3: What software architectures best suit this type of appropriated interaction and
developers’ designing to support such interaction?
Through a thorough review of existing literature, and the extensive study of several large
ubicomp systems, the issues when presenting oneself through technology are identified.
The main issues identified are hiding and revealing, and accountability. These are built into
a framework that acts as a reference for designers wishing to support impression
management. An architecture for supporting impression management has also been
developed that conforms to this framework and its evolution is documented later in the
thesis. A demonstration of this architecture in a multi-player mobile experience is
subsequently presented