96 research outputs found
Middleware services for distributed virtual environments
PhD ThesisDistributed Virtual Environments (DVEs) are virtual environments which allow
dispersed users to interact with each other and the virtual world through the
underlying network.
Scalability is a major challenge in building a successful DVE, which is directly
affected by the volume of message exchange. Different techniques have been
deployed to reduce the volume of message exchange in order to support large
numbers of simultaneous participants in a DVE. Interest management is a
popular technique for filtering unnecessary message exchange between users.
The rationale behind interest management is to resolve the "interests" of users
and decide whether messages should be exchanged between them. There are
three basic interest management approaches: region-based, aura-based and
hybrid approaches. However, if the time taken for an interest management
approach to determine interests is greater than the duration of the interaction, it
is not possible to guarantee interactions will occur correctly or at all. This is
termed the Missed Interaction Problem, which all existing interest management
approaches are susceptible to.
This thesis provides a new aura-based interest management approach, termed
Predictive Interest management (PIM), to alleviate the missed interaction
problem. PIM uses an enlarged aura to detect potential aura-intersections and
iii
initiate message exchange. It utilises variable message exchange frequencies,
proportional to the intersection degree of the objects' expanded auras, to restrict
bandwidth usage. This thesis provides an experimental system, the PIM system,
which couples predictive interest management with the de-centralised server
communication model. It utilises the Common Object Request Broker
Architecture (CORBA) middleware standard to provide an interoperable
middleware for DVEs. Experimental results are provided to demonstrate that
PIM provides a scalable interest management approach which alleviates the
missed interaction problem
Middleware services for distributed virtual environments
PhD ThesisDistributed Virtual Environments (DVEs) are virtual environments which allow
dispersed users to interact with each other and the virtual world through the
underlying network.
Scalability is a major challenge in building a successful DVE, which is directly
affected by the volume of message exchange. Different techniques have been
deployed to reduce the volume of message exchange in order to support large
numbers of simultaneous participants in a DVE. Interest management is a
popular technique for filtering unnecessary message exchange between users.
The rationale behind interest management is to resolve the "interests" of users
and decide whether messages should be exchanged between them. There are
three basic interest management approaches: region-based, aura-based and
hybrid approaches. However, if the time taken for an interest management
approach to determine interests is greater than the duration of the interaction, it
is not possible to guarantee interactions will occur correctly or at all. This is
termed the Missed Interaction Problem, which all existing interest management
approaches are susceptible to.
This thesis provides a new aura-based interest management approach, termed
Predictive Interest management (PIM), to alleviate the missed interaction
problem. PIM uses an enlarged aura to detect potential aura-intersections and
iii
initiate message exchange. It utilises variable message exchange frequencies,
proportional to the intersection degree of the objects' expanded auras, to restrict
bandwidth usage. This thesis provides an experimental system, the PIM system,
which couples predictive interest management with the de-centralised server
communication model. It utilises the Common Object Request Broker
Architecture (CORBA) middleware standard to provide an interoperable
middleware for DVEs. Experimental results are provided to demonstrate that
PIM provides a scalable interest management approach which alleviates the
missed interaction problem
Collaborative e-science architecture for Reaction Kinetics research community
This paper presents a novel collaborative e-science architecture (CeSA) to address two challenging issues in e-science that arise from the management of heterogeneous distributed environments: (i) how to provide individual scientists an integrated environment to collaborate with each other in distributed, loosely coupled research communities where each member might be using a disparate range of tools; and (ii) how to provide easy access to a range of computationally intensive resources from a desktop. The Reaction Kinetics research community was used to capture the requirements and in the evaluation of the proposed architecture. The result demonstrated the feasibility of the approach and the potential benefits of the CeSA
Fault Tolerant Adaptive Parallel and Distributed Simulation through Functional Replication
This paper presents FT-GAIA, a software-based fault-tolerant parallel and
distributed simulation middleware. FT-GAIA has being designed to reliably
handle Parallel And Distributed Simulation (PADS) models, which are needed to
properly simulate and analyze complex systems arising in any kind of scientific
or engineering field. PADS takes advantage of multiple execution units run in
multicore processors, cluster of workstations or HPC systems. However, large
computing systems, such as HPC systems that include hundreds of thousands of
computing nodes, have to handle frequent failures of some components. To cope
with this issue, FT-GAIA transparently replicates simulation entities and
distributes them on multiple execution nodes. This allows the simulation to
tolerate crash-failures of computing nodes. Moreover, FT-GAIA offers some
protection against Byzantine failures, since interaction messages among the
simulated entities are replicated as well, so that the receiving entity can
identify and discard corrupted messages. Results from an analytical model and
from an experimental evaluation show that FT-GAIA provides a high degree of
fault tolerance, at the cost of a moderate increase in the computational load
of the execution units.Comment: arXiv admin note: substantial text overlap with arXiv:1606.0731
A Reflective Platform for Highly Adaptive Multi-Cloud Systems
International audienceCloud platforms are increasingly used for hosting a broad diversity of services from traditional e-commerce applications to interactive web-based IDEs. However, we observe that the prolif- eration of offers by Cloud vendors raises several challenges. Developers will not only have to deploy applications for a specific Cloud, but will also have to consider migrating services from one cloud to another, and to manage applications spanning multiple Clouds. In this paper, we therefore report on a first experiment we conducted to build a multi-Cloud system on top of thirteen existing IaaS/PaaS. From this experiment, we advocate for two dimensions of adaptability - design and execution time - that applications for such systems require to exhibit. Finally, we propose a roadmap for future multi-Cloud systems
Recommended from our members
A grid computing framework for commercial simulation packages
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.An increased need for collaborative research among different organizations, together with continuing advances in communication technology and computer hardware, has facilitated the development of distributed systems that can provide users non-trivial access to geographically dispersed computing resources (processors, storage, applications, data, instruments, etc.) that are administered in multiple computer domains. The term grid computing or grids is popularly used to refer to such distributed systems. A broader definition of grid computing includes the use of computing resources within an organization for running organization-specific applications. This research is in the context of using grid computing within an enterprise to maximize the use of available hardware and software resources for processing enterprise applications. Large scale scientific simulations have traditionally been the primary benefactor of grid computing. The application of this technology to simulation in industry has, however, been negligible. This research investigates how grid technology can be effectively exploited by simulation practitioners using Windows-based commercially available simulation packages to model simulations in industry. These packages are commonly referred to as Commercial Off-The-Shelf (COTS) Simulation Packages (CSPs). The study identifies several higher level grid services that could be potentially used to support the practise of simulation in industry. It proposes a grid computing framework to investigate these services in the context of CSP-based simulations. This framework is called the CSP-Grid Computing (CSP-GC) Framework. Each identified higher level grid service in this framework is referred to as a CSP-specific service. A total of six case studies are presented to experimentally evaluate how grid computing technologies can be used together with unmodified simulation packages to support some of the CSP-specific services. The contribution of this thesis is the CSP-GC framework that identifies how simulation practise in industry may benefit from the use of grid technology. A further contribution is the recognition of specific grid computing software (grid middleware) that can possibly be used together with existing CSPs to provide grid support. With its focus on end-users and end-user tools, it is intended that this research will encourage wider adoption of grid computing in the workplace and that simulation users will derive benefit from using this technology
04451 Abstracts Collection -- Future Generation Grids
The Dagstuhl Seminar 04451 "Future Generation Grid" was held in the International
Conference and Research Center (IBFI), Schloss Dagstuhl from 1st
to 5th November 2004. The focus of the seminar was on open problems and
future challenges in the design of next generation Grid systems. A total of 45
participants presented their current projects, research plans, and new ideas in
the area of Grid technologies. Several evening sessions with vivid discussions
on future trends complemented the talks. This report gives an overview of the
background and the findings of the seminar
Cross-domain interoperability using federated interoperable semantic IoT/Cloud testbeds and applications: The FIESTA-IoT approach
This work is funded by the European Commission under the EU-H2020 Project Grant ”Federated Interoperable Semantic IoT/cloudTestbeds andApplications (FIESTA)” with the Grant Agreement No. CNECT-ICT-643943
- …