2,078 research outputs found
Recommended from our members
Multimedia delivery in the future internet
The term “Networked Media” implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizens’ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications “on the move”, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
Video-on-Demand over Internet: a survey of existing systems and solutions
Video-on-Demand is a service where movies are delivered to distributed users with low delay and free interactivity. The traditional client/server architecture experiences scalability issues to provide video streaming services, so there have been many proposals of systems, mostly based on a peer-to-peer or on a hybrid server/peer-to-peer solution, to solve this issue. This work presents a survey of the currently existing or proposed systems and solutions, based upon a subset of representative systems, and defines selection criteria allowing to classify these systems. These criteria are based on common questions such as, for example, is it video-on-demand or live streaming, is the architecture based on content delivery network, peer-to-peer or both, is the delivery overlay tree-based or mesh-based, is the system push-based or pull-based, single-stream or multi-streams, does it use data coding, and how do the clients choose their peers. Representative systems are briefly described to give a summarized overview of the proposed solutions, and four ones are analyzed in details. Finally, it is attempted to evaluate the most promising solutions for future experiments. Résumé La vidéo à la demande est un service où des films sont fournis à distance aux utilisateurs avec u
Proof-of-Concept Application - Annual Report Year 1
In this document the Cat-COVITE Application for use in the CATNETS Project is introduced and motivated. Furthermore an introduction to the catallactic middleware and Web Services Agreement (WS-Agreement) concepts is given as a basis for the future work. Requirements for the application of Cat-COVITE with in catallactic systems are analysed. Finally the integration of the Cat-COVITE application and the catallactic middleware is described. --Grid Computing
Ad-hoc Stream Adaptive Protocol
With the growing market of smart-phones, sophisticated applications that do extensive computation are common on mobile platform; and with consumers’ high expectation of technologies to stay connected on the go, academic researchers and industries have been making efforts to find ways to stream multimedia contents to mobile devices. However, the restricted wireless channel bandwidth, unstable nature of wireless channels, and unpredictable nature of mobility, has been the major road block for wireless streaming advance forward. In this paper, various recent studies on mobility and P2P system proposal are explained and analyzed, and propose a new design based on existing P2P systems, aimed to solve the wireless and mobility issues
Intelligent query processing in P2P networks: semantic issues and routing algorithms
P2P networks have become a commonly used way of disseminating content on the Internet. In this context, constructing efficient and distributed P2P routing algorithms for complex environments that include a huge number of distributed nodes with different computing and network capabilities is a major challenge. In the last years, query routing algorithms have evolved by taking into account different features (provenance, nodes' history, topic similarity, etc.). Such features are usually stored in auxiliary data structures (tables, matrices, etc.), which provide an extra knowledge engineering layer on top of the network, resulting in an added semantic value for specifying algorithms for efficient query routing. This article examines the main existing algorithms for query routing in unstructured P2P networks in which semantic aspects play a major role. A general comparative analysis is included, associated with a taxonomy of P2P networks based on their degree of decentralization and the different approaches adopted to exploit the available semantic aspects.Fil: Nicolini, Ana Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; ArgentinaFil: Lorenzetti, Carlos Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; ArgentinaFil: Maguitman, Ana Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; ArgentinaFil: Chesñevar, Carlos Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; Argentin
A lightweight distributed super peer election algorithm for unstructured dynamic P2P systems
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de ComputadoresNowadays with the current growth of information exchange, and the increasing mobility of devices, it becomes essential to use technology to monitor this development. For that P2P networks are used, the exchange of information between agencies is facilitated, these now being applied in mobile networks, including MANETs, where they have special features such as the fact that they are semi-centralized, where it takes peers more ability to make a greater role in the network. But those peer with more capacity, which are used in the optimization of various parameters of these systems, such as optimization\to research, are difficult to identify due to the fact that the network does not have a fixed topology, be constantly changing, (we like to go online and offline, to change position, etc.) and not to allow the exchange of large messages. To this end, this thesis proposes a distributed election algorithm of us greater capacity among several possible goals, enhance research in the network. This includes distinguishing characteristics, such as election without global knowledge network, minimal exchange of messages, distributed decision made without dependence on us and the possibility of influencing the election outcome as the special needs of the network
Analysis of current middleware used in peer-to-peer and grid implementations for enhancement by catallactic mechanisms
This deliverable describes the work done in task 3.1, Middleware analysis: Analysis of current middleware used in peer-to-peer and grid implementations for enhancement by catallactic mechanisms from work package 3, Middleware Implementation. The document is divided in four parts: The introduction with application scenarios and middleware requirements, Catnets middleware architecture, evaluation of existing middleware toolkits, and conclusions. -- Die Arbeit definiert Anforderungen an Grid und Peer-to-Peer Middleware Architekturen und analysiert diese auf ihre Eignung für die prototypische Umsetzung der Katallaxie. Eine Middleware-Architektur für die Umsetzung der Katallaxie in Application Layer Netzwerken wird vorgestellt.Grid Computing
Trade-off among timeliness, messages and accuracy for large-Ssale information management
The increasing amount of data and the number of nodes in large-scale environments
require new techniques for information management. Examples of such environments
are the decentralized infrastructures of Computational Grid and Computational
Cloud applications. These large-scale applications need different kinds
of aggregated information such as resource monitoring, resource discovery or economic
information. The challenge of providing timely and accurate information
in large scale environments arise from the distribution of the information. Reasons
for delays in distributed information system are a long information transmission
time due to the distribution, churn and failures.
A problem of large applications such as peer-to-peer (P2P) systems is the increasing
retrieval time of the information due to the decentralization of the data
and the failure proneness. However, many applications need a timely information
provision. Another problem is an increasing network consumption when the application
scales to millions of users and data. Using approximation techniques allows
reducing the retrieval time and the network consumption. However, the usage of
approximation techniques decreases the accuracy of the results. Thus, the remaining
problem is to offer a trade-off in order to solve the conflicting requirements of
fast information retrieval, accurate results and low messaging cost.
Our goal is to reach a self-adaptive decision mechanism to offer a trade-off
among the retrieval time, the network consumption and the accuracy of the result.
Self-adaption enables distributed software to modify its behavior based on
changes in the operating environment. In large-scale information systems that use
hierarchical data aggregation, we apply self-adaptation to control the approximation
used for the information retrieval and reduces the network consumption and
the retrieval time. The hypothesis of the thesis is that approximation techniquescan reduce the retrieval time and the network consumption while guaranteeing an
accuracy of the results, while considering user’s defined priorities.
First, this presented research addresses the problem of a trade-off among a
timely information retrieval, accurate results and low messaging cost by proposing
a summarization algorithm for resource discovery in P2P-content networks.
After identifying how summarization can improve the discovery process, we propose
an algorithm which uses a precision-recall metric to compare the accuracy
and to offer a user-driven trade-off. Second, we propose an algorithm that applies
a self-adaptive decision making on each node. The decision is about the pruning
of the query and returning the result instead of continuing the query. The pruning
reduces the retrieval time and the network consumption at the cost of a lower accuracy
in contrast to continuing the query. The algorithm uses an analytic hierarchy
process to assess the user’s priorities and to propose a trade-off in order to satisfy
the accuracy requirements with a low message cost and a short delay.
A quantitative analysis evaluates our presented algorithms with a simulator,
which is fed with real data of a network topology and the nodes’ attributes. The
usage of a simulator instead of the prototype allows the evaluation in a large scale
of several thousands of nodes. The algorithm for content summarization is evaluated
with half a million of resources and with different query types. The selfadaptive
algorithm is evaluated with a simulator of several thousands of nodes
that are created from real data. A qualitative analysis addresses the integration
of the simulator’s components in existing market frameworks for Computational
Grid and Cloud applications.
The proposed content summarization algorithm reduces the information retrieval
time from a logarithmic increase to a constant factor. Furthermore, the
message size is reduced significantly by applying the summarization technique.
For the user, a precision-recall metric allows defining the relation between the retrieval
time and the accuracy. The self-adaptive algorithm reduces the number of
messages needed from an exponential increase to a constant factor. At the same
time, the retrieval time is reduced to a constant factor under an increasing number
of nodes. Finally, the algorithm delivers the data with the required accuracy
adjusting the depth of the query according to the network conditions.La gestió de la informació exigeix noves tècniques que tractin amb la creixent
quantitat de dades i nodes en entorns a gran escala. Alguns exemples d’aquests
entorns són les infraestructures descentralitzades de Computacional Grid i Cloud.
Les aplicacions a gran escala necessiten diferents classes d’informació agregada
com monitorització de recursos i informació econòmica. El desafiament de proporcionar
una provisió ràpida i acurada d’informació en ambients de grans escala
sorgeix de la distribució de la informació. Una raó és que el sistema d’informació
ha de tractar amb l’adaptabilitat i fracassos d’aquests ambients.
Un problema amb aplicacions molt grans com en sistemes peer-to-peer (P2P)
és el creixent temps de recuperació de l’informació a causa de la descentralització
de les dades i la facilitat al fracàs. No obstant això, moltes aplicacions necessiten
una provisió d’informació puntual. A més, alguns usuaris i aplicacions accepten
inexactituds dels resultats si la informació es reparteix a temps. A més i més, el
consum de xarxa creixent fa que sorgeixi un altre problema per l’escalabilitat del
sistema. La utilització de tècniques d’aproximació permet reduir el temps de recuperació
i el consum de xarxa. No obstant això, l’ús de tècniques d’aproximació
disminueix la precisió dels resultats. Així, el problema restant és oferir un compromís
per resoldre els requisits en conflicte d’extracció de la informació ràpida,
resultats acurats i cost d’enviament baix.
El nostre objectiu és obtenir un mecanisme de decisió completament autoadaptatiu
per tal d’oferir el compromís entre temps de recuperació, consum de
xarxa i precisió del resultat. Autoadaptacío permet al programari distribuït modificar
el seu comportament en funció dels canvis a l’entorn d’operació. En sistemes
d’informació de gran escala que utilitzen agregació de dades jeràrquica,
l’auto-adaptació permet controlar l’aproximació utilitzada per a l’extracció de la informació i redueixen el consum de xarxa i el temps de recuperació. La hipòtesi
principal d’aquesta tesi és que els tècniques d’aproximació permeten reduir el
temps de recuperació i el consum de xarxa mentre es garanteix una precisió adequada
definida per l’usari.
La recerca que es presenta, introdueix un algoritme de sumarització de continguts
per a la descoberta de recursos a xarxes de contingut P2P. Després d’identificar
com sumarització pot millorar el procés de descoberta, proposem una mètrica que
s’utilitza per comparar la precisió i oferir un compromís definit per l’usuari. Després,
introduïm un algoritme nou que aplica l’auto-adaptació a un ordre per satisfer
els requisits de precisió amb un cost de missatge baix i un retard curt. Basat
en les prioritats d’usuari, l’algoritme troba automàticament un compromís.
L’anàlisi quantitativa avalua els algoritmes presentats amb un simulador per
permetre l’evacuació d’uns quants milers de nodes. El simulador s’alimenta amb
dades d’una topologia de xarxa i uns atributs dels nodes reals. L’algoritme de
sumarització de contingut s’avalua amb mig milió de recursos i amb diferents
tipus de sol·licituds. L’anàlisi qualitativa avalua la integració del components del
simulador en estructures de mercat existents per a aplicacions de Computacional
Grid i Cloud. Així, la funcionalitat implementada del simulador (com el procés
d’agregació i la query language) és comprovada per la integració de prototips.
L’algoritme de sumarització de contingut proposat redueix el temps d’extracció
de l’informació d’un augment logarítmic a un factor constant. A més, també permet
que la mida del missatge es redueix significativament. Per a l’usuari, una
precision-recall mètric permet definir la relació entre el nivell de precisió i el
temps d’extracció de la informació. Alhora, el temps de recuperació es redueix
a un factor constant sota un nombre creixent de nodes. Finalment, l’algoritme
reparteix les dades amb la precisió exigida i ajusta la profunditat de la sol·licitud
segons les condicions de xarxa. Els algoritmes introduïts són prometedors per ser
utilitzats per l’agregació d’informació en nous sistemes de gestió de la informació
de gran escala en el futur
A patient agent controlled customized blockchain based framework for internet of things
Although Blockchain implementations have emerged as revolutionary technologies for various industrial applications including cryptocurrencies, they have not been widely deployed to store data streaming from sensors to remote servers in architectures known as Internet of Things. New Blockchain for the Internet of Things models promise secure solutions for eHealth, smart cities, and other applications. These models pave the way for continuous monitoring of patient’s physiological signs with wearable sensors to augment traditional medical practice without recourse to storing data with a trusted authority. However, existing Blockchain algorithms cannot accommodate the huge volumes, security, and privacy requirements of health data. In this thesis, our first contribution is an End-to-End secure eHealth architecture that introduces an intelligent Patient Centric Agent. The Patient Centric Agent executing on dedicated hardware manages the storage and access of streams of sensors generated health data, into a customized Blockchain and other less secure repositories. As IoT devices cannot host Blockchain technology due to their limited memory, power, and computational resources, the Patient Centric Agent coordinates and communicates with a private customized Blockchain on behalf of the wearable devices. While the adoption of a Patient Centric Agent offers solutions for addressing continuous monitoring of patients’ health, dealing with storage, data privacy and network security issues, the architecture is vulnerable to Denial of Services(DoS) and single point of failure attacks. To address this issue, we advance a second contribution; a decentralised eHealth system in which the Patient Centric Agent is replicated at three levels: Sensing Layer, NEAR Processing Layer and FAR Processing Layer. The functionalities of the Patient Centric Agent are customized to manage the tasks of the three levels. Simulations confirm protection of the architecture against DoS attacks. Few patients require all their health data to be stored in Blockchain repositories but instead need to select an appropriate storage medium for each chunk of data by matching their personal needs and preferences with features of candidate storage mediums. Motivated by this context, we advance third contribution; a recommendation model for health data storage that can accommodate patient preferences and make storage decisions rapidly, in real-time, even with streamed data. The mapping between health data features and characteristics of each repository is learned using machine learning. The Blockchain’s capacity to make transactions and store records without central oversight enables its application for IoT networks outside health such as underwater IoT networks where the unattended nature of the nodes threatens their security and privacy. However, underwater IoT differs from ground IoT as acoustics signals are the communication media leading to high propagation delays, high error rates exacerbated by turbulent water currents. Our fourth contribution is a customized Blockchain leveraged framework with the model of Patient-Centric Agent renamed as Smart Agent for securely monitoring underwater IoT. Finally, the smart Agent has been investigated in developing an IoT smart home or cities monitoring framework. The key algorithms underpinning to each contribution have been implemented and analysed using simulators.Doctor of Philosoph
- …