41 research outputs found
Airborne Directional Networking: Topology Control Protocol Design
This research identifies and evaluates the impact of several architectural design choices in relation to airborne networking in contested environments related to autonomous topology control. Using simulation, we evaluate topology reconfiguration effectiveness using classical performance metrics for different point-to-point communication architectures. Our attention is focused on the design choices which have the greatest impact on reliability, scalability, and performance. In this work, we discuss the impact of several practical considerations of airborne networking in contested environments related to autonomous topology control modeling. Using simulation, we derive multiple classical performance metrics to evaluate topology reconfiguration effectiveness for different point-to-point communication architecture attributes for the purpose of qualifying protocol design elements
Solving key design issues for massively multiplayer online games on peer-to-peer architectures
Massively Multiplayer Online Games (MMOGs) are increasing in both popularity and
scale on the Internet and are predominantly implemented by Client/Server architectures.
While such a classical approach to distributed system design offers many benefits, it suffers
from significant technical and commercial drawbacks, primarily reliability and scalability
costs. This realisation has sparked recent research interest in adapting MMOGs
to Peer-to-Peer (P2P) architectures.
This thesis identifies six key design issues to be addressed by P2P MMOGs, namely
interest management, event dissemination, task sharing, state persistency, cheating mitigation,
and incentive mechanisms. Design alternatives for each issue are systematically
compared, and their interrelationships discussed. How well representative P2P MMOG
architectures fulfil the design criteria is also evaluated. It is argued that although P2P
MMOG architectures are developing rapidly, their support for task sharing and incentive
mechanisms still need to be improved.
The design of a novel framework for P2P MMOGs, Mediator, is presented. It employs a
self-organising super-peer network over a P2P overlay infrastructure, and addresses the
six design issues in an integrated system. The Mediator framework is extensible, as it
supports flexible policy plug-ins and can accommodate the introduction of new superpeer
roles. Key components of this framework have been implemented and evaluated
with a simulated P2P MMOG.
As the Mediator framework relies on super-peers for computational and administrative
tasks, membership management is crucial, e.g. to allow the system to recover from
super-peer failures. A new technology for this, namely Membership-Aware Multicast
with Bushiness Optimisation (MAMBO), has been designed, implemented and evaluated.
It reuses the communication structure of a tree-based application-level multicast
to track group membership efficiently. Evaluation of a demonstration application shows
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that MAMBO is able to quickly detect and handle peers joining and leaving. Compared
to a conventional supervision architecture, MAMBO is more scalable, and yet incurs
less communication overheads. Besides MMOGs, MAMBO is suitable for other P2P
applications, such as collaborative computing and multimedia streaming.
This thesis also presents the design, implementation and evaluation of a novel task
mapping infrastructure for heterogeneous P2P environments, Deadline-Driven Auctions
(DDA). DDA is primarily designed to support NPC host allocation in P2P MMOGs, and
specifically in the Mediator framework. However, it can also support the sharing of computational
and interactive tasks with various deadlines in general P2P applications. Experimental
and analytical results demonstrate that DDA efficiently allocates computing
resources for large numbers of real-time NPC tasks in a simulated P2P MMOG with approximately
1000 players. Furthermore, DDA supports gaming interactivity by keeping
the communication latency among NPC hosts and ordinary players low. It also supports
flexible matchmaking policies, and can motivate application participants to contribute
resources to the system
Mobile Ad Hoc Networks
Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms
Management and Security in the Age of Hyperconnectivity:10th IFIP WG 6.6 International Conference on Autonomous Infrastructure, Management, and Security, AIMS 2016, Munich, Germany, June 20-23, 2016, Proceedings
Antennas and Propagation Aspects for Emerging Wireless Communication Technologies
The increasing demand for high data rate applications and the delivery of zero-latency multimedia content drives technological evolutions towards the design and implementation of next-generation broadband wireless networks. In this context, various novel technologies have been introduced, such as millimeter wave (mmWave) transmission, massive multiple input multiple output (MIMO) systems, and non-orthogonal multiple access (NOMA) schemes in order to support the vision of fifth generation (5G) wireless cellular networks. The introduction of these technologies, however, is inextricably connected with a holistic redesign of the current transceiver structures, as well as the network architecture reconfiguration. To this end, ultra-dense network deployment along with distributed massive MIMO technologies and intermediate relay nodes have been proposed, among others, in order to ensure an improved quality of services to all mobile users. In the same framework, the design and evaluation of novel antenna configurations able to support wideband applications is of utmost importance for 5G context support. Furthermore, in order to design reliable 5G systems, the channel characterization in these frequencies and in the complex propagation environments cannot be ignored because it plays a significant role. In this Special Issue, fourteen papers are published, covering various aspects of novel antenna designs for broadband applications, propagation models at mmWave bands, the deployment of NOMA techniques, radio network planning for 5G networks, and multi-beam antenna technologies for 5G wireless communications
Efficient Content-based Routing, Mobility-aware Topologies, and Temporal Subspace Matching
Event-based systems are seen as good candidates for supporting distributed applications in dynamic and ubiquitous environments because they support decoupled and asynchronous many-to-many information dissemination. Event systems are widely used, because asynchronous messaging provides a flexible alternative to RPC (Remote Procedure Call). They are typically implemented using an overlay network of routers. A content-based router forwards event messages based on filters that are installed by subscribers and other routers. The filters are organized into a routing table in order to forward incoming events to proper subscribers and neighbouring routers.
This thesis addresses the optimization of content-based routing tables organized using the covering relation and presents novel data structures and configurations for improving local and distributed operation. Data structures are needed for organizing filters into a routing table that supports efficient matching and runtime operation. We present novel results on dynamic filter merging and the integration of filter merging with content-based routing tables. In addition, the thesis examines the cost of client mobility using different protocols and routing topologies.
We also present a new matching technique called temporal subspace matching. The technique combines two new features. The first feature, temporal operation, supports notifications, or content profiles, that persist in time. The second feature, subspace matching, allows more expressive semantics, because notifications may contain intervals and be defined as subspaces of the content space. We also present an application of temporal subspace matching pertaining to metadata-based continuous collection and object tracking.Tapahtumapohjaiset järjestelmät nähdään hyvänä tapana tukea ja kehittää hajautettuja sovelluksia dynaamisissa ympäristöissä. Nämä järjestelmät tukevat asynkronista viestien välitystä. Tapahtumapohjaisia järjestelmiä käytetään, koska asynkroninen viestintä mahdollistaa etäproseduurikutsuja vapaammat sidokset sovellusten välille.
Tapahtumapohjaiset järjestelmät toteutetaan tyypillisesti ns. "overlay" verkkoina sovelluskerroksella. Sisältöpohjainen reititin välittää tapahtumaviestejä tilaajien asettamien suotimien (eng. filter) perusteella. Tiedon tilaajat ja tuottajat kytketään suotimien avulla niin että tuottajien tuottamat tapahtumat välittyvät aktiivisille tilaajille. Suodin valikoi viestivirrasta halutut viestit erityisten sääntöjen avulla. Suotimet järjestetään reititystauluksi, jonka perusteella päätetään kenelle reititin ohjaa viestejä.
Väitöskirja käsittelee suodinpohjaisten reititystaulujen optimointia ja esittää uusia tietorakenteita ja konfiguraatioita paikalliseen sekä hajautettuun toimintaan. Työssä esitetään yleinen formaali suotimien yhdistämismalli, joka integroidaan esitettyjen tietorakenteiden kanssa. Lisäksi työssä tutkitaan liikkuvien tilaajien ja tuottajien aiheuttamia kustannuksia.
Työssä esitetään myös uusi tekniikka aikaan kytketyn tiedon välitykseen. Tekniikka yhdistää kaksi uutta piirrettä. Ensimmäinen piirre on temporaalinen toiminta, jossa välitettävä tieto on määritetty olemaan voimassa tietyn ajanjakson. Toinen ominaisuus mahdollistaa sekä kyselyiden että datan, johon kyselyt kohdistuvat, määrittelyn moniulotteisten suotimien avulla. Työssä esitetään tekniikasta esimerkkisovellus, joka käsittelee joukkojen ja olioiden seurantaa