9 research outputs found
A lightweight distributed super peer election algorithm for unstructured dynamic P2P systems
Dissertação apresentada na Faculdade de CiĂȘncias e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia ElectrotĂ©cnica 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
Large-Scale Distributed Coalition Formation
The CyberCraft project is an effort to construct a large scale Distributed Multi-Agent System (DMAS) to provide autonomous Cyberspace defense and mission assurance for the DoD. It employs a small but flexible agent structure that is dynamically reconfigurable to accommodate new tasks and policies. This document describes research into developing protocols and algorithms to ensure continued mission execution in a system of one million or more agents, focusing on protocols for coalition formation and Command and Control. It begins by building large-scale routing algorithms for a Hierarchical Peer to Peer structured overlay network, called Resource-Clustered Chord (RC-Chord). RC-Chord introduces the ability to efficiently locate agents by resources that agents possess. Combined with a task model defined for CyberCraft, this technology feeds into an algorithm that constructs task coalitions in a large-scale DMAS. Experiments reveal the flexibility and effectiveness of these concepts for achieving maximum work throughput in a simulated CyberCraft environment
Geostry - a Peer-to-Peer System for Location-based Information
An interesting development is summarized by the notion of âUbiquitous Computingâ: In this area, miniature systems are integrated into everyday objects making these objects âsmartâ and able to communicate. Thereby, everyday objects can gather information about their state and their environment. By embedding this information into a model of the real world, which nowadays can be modeled very realistically using sophisticated 3D modeling techniques, it is possible to generate powerful digital world models. Not only can existing objects of the real world and their state be mapped into these world models, but additional information can be linked to these objects as well. The result is a symbiosis of the real world and digital information spaces.
In this thesis, we present a system that allows for an easy access to this information. In contrast to existing solutions our approach is not based on a server-client architecture. Geostry bases on a peer-to-peer system and thus incorporates all the advantages, such as self-organization, fairness (in terms of costs), scalability and many more. Setting up the network is realized through a decentralized bootstrapping protocol based on an existing Internet service to provide robustness and availability. To selectively find geographic-related information Geostry supports spatial queries. They - among other things - enable the user to search for information e.g. in a certain district only. Sometimes, a certain piece of information raises particular interest. To cope with the run on the single computer that provides this specific information, Geostry offers dynamic replication mechanisms. Thereby, the information is replicated for as long as the rush lasts. Thus, Geostry offers all aspects from setting up a network, providing access to geo-related information and replication methods to provide accessibility in times of high loads
A framework for the dynamic management of Peer-to-Peer overlays
Peer-to-Peer (P2P) applications have been associated with inefficient operation, interference with other network services and large operational costs for network providers. This thesis presents a framework which can help ISPs address these issues by means of intelligent management of peer behaviour. The proposed approach involves limited control of P2P overlays without interfering with the fundamental characteristics of peer autonomy and decentralised operation.
At the core of the management framework lays the Active Virtual Peer (AVP). Essentially intelligent peers operated by the network providers, the AVPs interact with the overlay from within, minimising redundant or inefficient traffic, enhancing overlay stability and facilitating the efficient and balanced use of available peer and network resources. They offer an âinsiderâsâ view of the overlay and permit the management of P2P functions in a compatible and non-intrusive manner. AVPs can support multiple P2P protocols and coordinate to perform functions collectively.
To account for the multi-faceted nature of P2P applications and allow the incorporation of modern techniques and protocols as they appear, the framework is based on a modular architecture. Core modules for overlay control and transit traffic minimisation are presented. Towards the latter, a number of suitable P2P content caching strategies are proposed.
Using a purpose-built P2P network simulator and small-scale experiments, it is demonstrated that the introduction of AVPs inside the network can significantly reduce inter-AS traffic, minimise costly multi-hop flows, increase overlay stability and load-balancing and offer improved peer transfer performance
Descoberta de recursos para sistemas de escala arbitrarias
Doutoramento em InformĂĄticaTecnologias de Computação DistribuĂda em larga escala tais como Cloud,
Grid, Cluster e Supercomputadores HPC estĂŁo a evoluir juntamente com a
emergĂȘncia revolucionĂĄria de modelos de mĂșltiplos nĂșcleos (por exemplo:
GPU, CPUs num Ășnico die, Supercomputadores em single die, Supercomputadores
em chip, etc) e avanços significativos em redes e soluçÔes de
interligação. No futuro, nĂłs de computação com milhares de nĂșcleos podem
ser ligados entre si para formar uma Ășnica unidade de computação
transparente que esconde das aplicaçÔes a complexidade e a natureza distribuĂda desses sistemas com mĂșltiplos nĂșcleos. A fim de beneficiar de forma
eficiente de todos os potenciais recursos nesses ambientes de computação
em grande escala com mĂșltiplos nĂșcleos ativos, a descoberta de recursos Ă© um elemento crucial para explorar ao mĂĄximo as capacidade de todos
os recursos heterogĂ©neos distribuĂdos, atravĂ©s do reconhecimento preciso e
localização desses recursos no sistema. A descoberta eficiente e escalåvel
de recursos ÂŽe um desafio para tais sistemas futuros, onde os recursos e as
infira-estruturas de computação e comunicação subjacentes são altamente
dinùmicas, hierarquizadas e heterogéneas. Nesta tese, investigamos o problema
da descoberta de recursos no que diz respeito aos requisitos gerais da
escalabilidade arbitrĂĄria de ambientes de computação futuros com mĂșltiplos
nĂșcleos ativos. A principal contribuição desta tese ÂŽe a proposta de uma
entidade de descoberta de recursos adaptativa hĂbrida (Hybrid Adaptive
Resource Discovery - HARD), uma abordagem de descoberta de recursos eficiente
e altamente escalĂĄvel, construĂda sobre uma sobreposição hierĂĄrquica
virtual baseada na auto-organizaçãoo e auto-adaptação de recursos de processamento
no sistema, onde os recursos computacionais sĂŁo organizados
em hierarquias distribuĂdas de acordo com uma proposta de modelo de
descriçãoo de recursos multi-camadas hierårquicas. Operacionalmente, em
cada camada, que consiste numa arquitetura ponto-a-ponto de mĂłdulos que,
interagindo uns com os outros, fornecem uma visĂŁo global da disponibilidade
de recursos num ambiente distribuĂdo grande, dinĂąmico e heterogĂ©neo. O
modelo de descoberta de recursos proposto fornece a adaptabilidade e flexibilidade
para executar consultas complexas através do apoio a um conjunto
de caracterĂsticas significativas (tais como multi-dimensional, variedade e
consulta agregada) apoiadas por uma correspondĂȘncia exata e parcial, tanto
para o conteĂșdo de objetos estĂ©ticos e dinĂąmicos. SimulaçÔes mostram
que o HARD pode ser aplicado a escalas arbitrĂĄrias de dinamismo, tanto
em termos de complexidade como de escala, posicionando esta proposta
como uma arquitetura adequada para sistemas futuros de mĂșltiplos nĂșcleos.
TambĂ©m contribuĂmos com a proposta de um regime de gestĂŁo eficiente
dos recursos para sistemas futuros que podem utilizar recursos distribuĂos
de forma eficiente e de uma forma totalmente descentralizada. Além disso,
aproveitando componentes de descoberta (RR-RPs) permite que a nossa
plataforma de gestĂŁo de recursos encontre e aloque dinamicamente recursos
disponĂeis que garantam os parĂąmetros de QoS pedidos.Large scale distributed computing technologies such as Cloud, Grid, Cluster
and HPC supercomputers are progressing along with the revolutionary emergence
of many-core designs (e.g. GPU, CPUs on single die, supercomputers
on chip, etc.) and significant advances in networking and interconnect solutions.
In future, computing nodes with thousands of cores may be connected
together to form a single transparent computing unit which hides from applications
the complexity and distributed nature of these many core systems. In
order to efficiently benefit from all the potential resources in such large scale
many-core-enabled computing environments, resource discovery is the vital
building block to maximally exploit the capabilities of all distributed heterogeneous
resources through precisely recognizing and locating those resources
in the system. The efficient and scalable resource discovery is challenging for
such future systems where the resources and the underlying computation and
communication infrastructures are highly-dynamic, highly-hierarchical and
highly-heterogeneous. In this thesis, we investigate the problem of resource
discovery with respect to the general requirements of arbitrary scale future
many-core-enabled computing environments. The main contribution of this
thesis is to propose Hybrid Adaptive Resource Discovery (HARD), a novel
efficient and highly scalable resource-discovery approach which is built upon
a virtual hierarchical overlay based on self-organization and self-adaptation
of processing resources in the system, where the computing resources are
organized into distributed hierarchies according to a proposed hierarchical
multi-layered resource description model. Operationally, at each layer, it
consists of a peer-to-peer architecture of modules that, by interacting with
each other, provide a global view of the resource availability in a large,
dynamic and heterogeneous distributed environment. The proposed resource
discovery model provides the adaptability and flexibility to perform complex
querying by supporting a set of significant querying features (such as
multi-dimensional, range and aggregate querying) while supporting exact
and partial matching, both for static and dynamic object contents. The
simulation shows that HARD can be applied to arbitrary scales of dynamicity,
both in terms of complexity and of scale, positioning this proposal as a
proper architecture for future many-core systems. We also contributed to
propose a novel resource management scheme for future systems which
efficiently can utilize distributed resources in a fully decentralized fashion.
Moreover, leveraging discovery components (RR-RPs) enables our resource
management platform to dynamically find and allocate available resources
that guarantee the QoS parameters on demand
Techniques for improving predictability and message efficiency of gossip protocols
Ph.DDOCTOR OF PHILOSOPH
Implications of query caching for JXTA peers
This dissertation studies the caching of queries and how to cache in an efficient way, so that retrieving previously accessed data does not need any intermediary nodes between the data-source peer and the querying peer in super-peer P2P network. A precise algorithm was devised that demonstrated how queries can be deconstructed to provide greater flexibility for reusing their constituent elements. It showed how subsequent queries can make use of more than one previous query and any part of those queries to reconstruct direct data communication with one or more source peers that have supplied data previously. In effect, a new query can search and exploit the entire cached list of queries to construct the list of the data locations it requires that might match any locations previously accessed. The new method increases the likelihood of repeat queries being able to reuse earlier queries and provides a viable way of by-passing shared data indexes in structured networks. It could also increase the efficiency of unstructured networks by reducing traffic and the propensity for network flooding. In addition, performance evaluation for predicting query routing performance by using a UML sequence diagram is introduced. This new method of performance evaluation provides designers with information about when it is most beneficial to use caching and how the peer connections can optimize its exploitation