3,725 research outputs found
Cloud-efficient modelling and simulation of magnetic nano materials
Scientific simulations are rarely attempted in a cloud due to the substantial
performance costs of virtualization. Considerable communication overheads,
intolerable latencies, and inefficient hardware emulation are the main reasons why
this emerging technology has not been fully exploited. On the other hand, the
progress of computing infrastructure nowadays is strongly dependent on
perspective storage medium development, where efficient micromagnetic
simulations play a vital role in future memory design.
This thesis addresses both these topics by merging micromagnetic simulations
with the latest OpenStack cloud implementation while providing a time and costeffective alternative to expensive computing centers.
However, many challenges have to be addressed before a high-performance cloud
platform emerges as a solution for problems in micromagnetic research
communities. First, the best solver candidate has to be selected and further
improved, particularly in the parallelization and process communication domain.
Second, a 3-level cloud communication hierarchy needs to be recognized and
each segment adequately addressed. The required steps include breaking the VMisolation for the hostâs shared memory activation, cloud network-stack tuning,
optimization, and efficient communication hardware integration.
The project work concludes with practical measurements and confirmation of
successfully implemented simulation into an open-source cloud environment. It is
achieved that the renewed Magpar solver runs for the first time in the OpenStack
cloud by using ivshmem for shared memory communication. Also, extensive
measurements proved the effectiveness of our solutions, yielding from sixty
percent to over ten times better results than those achieved in the standard cloud.Aufgrund der erheblichen Leistungskosten der Virtualisierung werden
wissenschaftliche Simulationen in einer Cloud selten versucht. BetrÀchtlicher
Kommunikationsaufwand, erhebliche Latenzen und ineffiziente
Hardwareemulation sind die HauptgrĂŒnde, warum diese aufkommende
Technologie nicht vollstÀndig genutzt wurde. Andererseits hÀngt der Fortschritt der
Computertechnologie heutzutage stark von der Entwicklung perspektivischer
Speichermedien ab, bei denen effiziente mikromagnetische Simulationen eine
wichtige Rolle fĂŒr die zukĂŒnftige Speichertechnologie spielen.
Diese Arbeit befasst sich mit diesen beiden Themen, indem mikromagnetische
Simulationen mit der neuesten OpenStack Cloud-Implementierung
zusammengefĂŒhrt werden, um eine zeit- und kostengĂŒnstige Alternative zu teuren
Rechenzentren bereitzustellen.
Viele Herausforderungen mĂŒssen jedoch angegangen werden, bevor eine
leistungsstarke Cloud-Plattform als Lösung fĂŒr Probleme in mikromagnetischen
Forschungsgemeinschaften entsteht. ZunĂ€chst muss der beste Kandidat fĂŒr die
Lösung ausgewÀhlt und weiter verbessert werden, insbesondere im Bereich der
Parallelisierung und Prozesskommunikation. Zweitens muss eine 3-stufige CloudKommunikationshierarchie erkannt und jedes Segment angemessen adressiert
werden. Die erforderlichen Schritte umfassen das Aufheben der VM-Isolation, um
den gemeinsam genutzten Speicher zwischen Cloud-Instanzen zu aktivieren, die
Optimierung des Cloud-Netzwerkstapels und die effiziente Integration von
Kommunikationshardware.
Die praktische Arbeit endet mit Messungen und der BestÀtigung einer erfolgreich
implementierten Simulation in einer Open-Source Cloud-Umgebung. Als Ergebnis
haben wir erreicht, dass der neu erstellte Magpar-Solver zum ersten Mal in der
OpenStack Cloud ausgefĂŒhrt wird, indem ivshmem fĂŒr die Shared-Memory
Kommunikation verwendet wird. Umfangreiche Messungen haben auch die
Wirksamkeit unserer Lösungen bewiesen und von sechzig Prozent bis zu zehnmal
besseren Ergebnissen als in der Standard Cloud gefĂŒhrt
A novel multipath-transmission supported software defined wireless network architecture
The inflexible management and operation of today\u27s wireless access networks cannot meet the increasingly growing specific requirements, such as high mobility and throughput, service differentiation, and high-level programmability. In this paper, we put forward a novel multipath-transmission supported software-defined wireless network architecture (MP-SDWN), with the aim of achieving seamless handover, throughput enhancement, and flow-level wireless transmission control as well as programmable interfaces. In particular, this research addresses the following issues: 1) for high mobility and throughput, multi-connection virtual access point is proposed to enable multiple transmission paths simultaneously over a set of access points for users and 2) wireless flow transmission rules and programmable interfaces are implemented into mac80211 subsystem to enable service differentiation and flow-level wireless transmission control. Moreover, the efficiency and flexibility of MP-SDWN are demonstrated in the performance evaluations conducted on a 802.11 based-testbed, and the experimental results show that compared to regular WiFi, our proposed MP-SDWN architecture achieves seamless handover and multifold throughput improvement, and supports flow-level wireless transmission control for different applications
Continuous and Concurrent Network Connection for Hardware Virtualization
This project addresses the network connectivity in virtualization for cloud
computing. Each Virtual Machine will be able to access the network concurrently
and obtains continuous internet connectivity without any disruption. This project
proposes a new method of resource sharing which is the Network Interface Card
(NIC) among the Virtual Machines with each of them having the full access to it with
near-native bandwidth. With this, could computing can perform resource allocation
more effectively. This will be essential to migrate the each Operating System
(Virtual Machine) that resides on one physical machine to another without disrupting
its internet or network connection
Building an Emulation Environment for Cyber Security Analyses of Complex Networked Systems
Computer networks are undergoing a phenomenal growth, driven by the rapidly
increasing number of nodes constituting the networks. At the same time, the
number of security threats on Internet and intranet networks is constantly
growing, and the testing and experimentation of cyber defense solutions
requires the availability of separate, test environments that best emulate the
complexity of a real system. Such environments support the deployment and
monitoring of complex mission-driven network scenarios, thus enabling the study
of cyber defense strategies under real and controllable traffic and attack
scenarios. In this paper, we propose a methodology that makes use of a
combination of techniques of network and security assessment, and the use of
cloud technologies to build an emulation environment with adjustable degree of
affinity with respect to actual reference networks or planned systems. As a
byproduct, starting from a specific study case, we collected a dataset
consisting of complete network traces comprising benign and malicious traffic,
which is feature-rich and publicly available
A framework for realistic real-time walkthroughs in a VR distributed environment
Virtual and augmented reality (VR/AR) are
increasingly being used in various business scenarios and
are important driving forces in technology development.
However the usage of these technologies in the home
environment is restricted due to several factors including
lack of low-cost (from the client point of view) highperformance
solutions. In this paper we present a general
client/server rendering architecture based on Real-Time
concepts, including support for a wide range of client
platforms and applications. The idea of focusing on the
real-time behaviour of all components involved in
distributed IP-based VR scenarios is new and has not been
addressed before, except for simple sub-solutions. This is
considered as âthe most significant problem with the IP
environmentâ [1]. Thus, the most important contribution of
this research will be the holistic approach, in which
networking, end-systems and rendering aspects are
integrated into a cost-effective infrastructure for building
distributed real-time VR applications on IP-based
networks
InterCloud: Utility-Oriented Federation of Cloud Computing Environments for Scaling of Application Services
Cloud computing providers have setup several data centers at different
geographical locations over the Internet in order to optimally serve needs of
their customers around the world. However, existing systems do not support
mechanisms and policies for dynamically coordinating load distribution among
different Cloud-based data centers in order to determine optimal location for
hosting application services to achieve reasonable QoS levels. Further, the
Cloud computing providers are unable to predict geographic distribution of
users consuming their services, hence the load coordination must happen
automatically, and distribution of services must change in response to changes
in the load. To counter this problem, we advocate creation of federated Cloud
computing environment (InterCloud) that facilitates just-in-time,
opportunistic, and scalable provisioning of application services, consistently
achieving QoS targets under variable workload, resource and network conditions.
The overall goal is to create a computing environment that supports dynamic
expansion or contraction of capabilities (VMs, services, storage, and database)
for handling sudden variations in service demands.
This paper presents vision, challenges, and architectural elements of
InterCloud for utility-oriented federation of Cloud computing environments. The
proposed InterCloud environment supports scaling of applications across
multiple vendor clouds. We have validated our approach by conducting a set of
rigorous performance evaluation study using the CloudSim toolkit. The results
demonstrate that federated Cloud computing model has immense potential as it
offers significant performance gains as regards to response time and cost
saving under dynamic workload scenarios.Comment: 20 pages, 4 figures, 3 tables, conference pape
State-of-the-Art in Parallel Computing with R
R is a mature open-source programming language for statistical computing and graphics. Many areas of statistical research are experiencing rapid growth in the size of data sets. Methodological advances drive increased use of simulations. A common approach is to use parallel computing. This paper presents an overview of techniques for parallel computing with R on computer clusters, on multi-core systems, and in grid computing. It reviews sixteen different packages, comparing them on their state of development, the parallel technology used, as well as on usability, acceptance, and performance. Two packages (snow, Rmpi) stand out as particularly useful for general use on computer clusters. Packages for grid computing are still in development, with only one package currently available to the end user. For multi-core systems four different packages exist, but a number of issues pose challenges to early adopters. The paper concludes with ideas for further developments in high performance computing with R. Example code is available in the appendix
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