57,853 research outputs found
The RAppArmor Package: Enforcing Security Policies in R Using Dynamic Sandboxing on Linux
The increasing availability of cloud computing and scientific super computers
brings great potential for making R accessible through public or shared
resources. This allows us to efficiently run code requiring lots of cycles and
memory, or embed R functionality into, e.g., systems and web services. However
some important security concerns need to be addressed before this can be put in
production. The prime use case in the design of R has always been a single
statistician running R on the local machine through the interactive console.
Therefore the execution environment of R is entirely unrestricted, which could
result in malicious behavior or excessive use of hardware resources in a shared
environment. Properly securing an R process turns out to be a complex problem.
We describe various approaches and illustrate potential issues using some of
our personal experiences in hosting public web services. Finally we introduce
the RAppArmor package: a Linux based reference implementation for dynamic
sandboxing in R on the level of the operating system
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Leveraging simulation practice in industry through use of desktop grid middleware
This chapter focuses on the collaborative use of computing resources to support decision making in industry. Through the use of middleware for desktop grid computing, the idle CPU cycles available on existing computing resources can be harvested and used for speeding-up the execution of applications that have “non-trivial” processing requirements. This chapter focuses on the desktop grid middleware BOINC and Condor, and discusses the integration of commercial simulation software together with free-to-download grid middleware so as to offer competitive advantage to organizations that opt for this technology. It is expected that the low-intervention integration approach presented in this chapter (meaning no changes to source code required) will appeal to both simulation practitioners (as simulations can be executed faster, which in turn would mean that more replications and optimization is possible in the same amount of time) and the management (as it can potentially increase the return on investment on existing resources)
Global Grids and Software Toolkits: A Study of Four Grid Middleware Technologies
Grid is an infrastructure that involves the integrated and collaborative use
of computers, networks, databases and scientific instruments owned and managed
by multiple organizations. Grid applications often involve large amounts of
data and/or computing resources that require secure resource sharing across
organizational boundaries. This makes Grid application management and
deployment a complex undertaking. Grid middlewares provide users with seamless
computing ability and uniform access to resources in the heterogeneous Grid
environment. Several software toolkits and systems have been developed, most of
which are results of academic research projects, all over the world. This
chapter will focus on four of these middlewares--UNICORE, Globus, Legion and
Gridbus. It also presents our implementation of a resource broker for UNICORE
as this functionality was not supported in it. A comparison of these systems on
the basis of the architecture, implementation model and several other features
is included.Comment: 19 pages, 10 figure
Phenomenology Tools on Cloud Infrastructures using OpenStack
We present a new environment for computations in particle physics
phenomenology employing recent developments in cloud computing. On this
environment users can create and manage "virtual" machines on which the
phenomenology codes/tools can be deployed easily in an automated way. We
analyze the performance of this environment based on "virtual" machines versus
the utilization of "real" physical hardware. In this way we provide a
qualitative result for the influence of the host operating system on the
performance of a representative set of applications for phenomenology
calculations.Comment: 25 pages, 12 figures; information on memory usage included, as well
as minor modifications. Version to appear in EPJ
A Taxonomy of Data Grids for Distributed Data Sharing, Management and Processing
Data Grids have been adopted as the platform for scientific communities that
need to share, access, transport, process and manage large data collections
distributed worldwide. They combine high-end computing technologies with
high-performance networking and wide-area storage management techniques. In
this paper, we discuss the key concepts behind Data Grids and compare them with
other data sharing and distribution paradigms such as content delivery
networks, peer-to-peer networks and distributed databases. We then provide
comprehensive taxonomies that cover various aspects of architecture, data
transportation, data replication and resource allocation and scheduling.
Finally, we map the proposed taxonomy to various Data Grid systems not only to
validate the taxonomy but also to identify areas for future exploration.
Through this taxonomy, we aim to categorise existing systems to better
understand their goals and their methodology. This would help evaluate their
applicability for solving similar problems. This taxonomy also provides a "gap
analysis" of this area through which researchers can potentially identify new
issues for investigation. Finally, we hope that the proposed taxonomy and
mapping also helps to provide an easy way for new practitioners to understand
this complex area of research.Comment: 46 pages, 16 figures, Technical Repor
Ellogon: A New Text Engineering Platform
This paper presents Ellogon, a multi-lingual, cross-platform, general-purpose
text engineering environment. Ellogon was designed in order to aid both
researchers in natural language processing, as well as companies that produce
language engineering systems for the end-user. Ellogon provides a powerful
TIPSTER-based infrastructure for managing, storing and exchanging textual data,
embedding and managing text processing components as well as visualising
textual data and their associated linguistic information. Among its key
features are full Unicode support, an extensive multi-lingual graphical user
interface, its modular architecture and the reduced hardware requirements.Comment: 7 pages, 9 figures. Will be presented to the Third International
Conference on Language Resources and Evaluation - LREC 200
Scaling Virtualized Smartphone Images in the Cloud
Üks selle Bakalaureuse töö eesmärkidest oli Android-x86 nutitelefoni platvormi juurutamine
pilvekeskkonda ja välja selgitamine, kas valitud instance on piisav virtualiseeritud nutitelefoni
platvormi juurutamiseks ning kui palju koormust see talub. Töös kasutati Amazoni instance'i
M1 Small, mis oli piisav, et juurutada Androidi virtualiseeritud platvormi, kuid jäi kesisemaks
kui mobiiltelefon, millel teste läbi viidi. M1 Medium instance'i tüüp oli sobivam ja näitas
paremaid tulemusi võrreldes telefoniga.
Teostati koormusteste selleks vastava tööriistaga Tsung, et näha, kui palju üheaegseid
kasutajaid instance talub. Testi läbiviimiseks paigaldasime Dalviku instance'ile Tomcat
serveri.
Pärast teste ühe eksemplariga, juurutasime külge Elastic Load Balancing ja
automaatse skaleerimise Amazon Auto Scaling tööriista. Esimene neist jaotas koormust
instance'ide
vahel.
Automaatse
skaleerimise
tööriista
kasutasime,
et
rakendada
horisontaalset skaleerimist meie Android-x86 instance'le. Kui CPU tõusis üle 60% kauemaks
kui üks minut, siis tehti eelmisele identne instance ja koormust saadeti edaspidi sinna. Seda
protseduuri vajadusel korrati maksimum kümne instance'ini. Meie teostusel olid tagasilöögid,
sest Elastic Load Balancer aegus 60 sekundi pärast ning me ei saanud kõikide välja
saadetud päringutele vastuseid. Serverisse saadetud faili kirjutamine ja kompileerimine olid
kulukad tegevused ja seega ei lõppenud kõik 60 sekundi jooksul. Me ei saanud koos Load
Balancer'iga läbiviidud testidest piisavalt andmeid, et teha järeldusi, kas virtualiseeritud
nutitelefoni platvorm Android on hästi või halvasti skaleeruv.In this thesis we deployed a smartphone image in an Amazon EC2 instance and ran stress tests on them to know how much users can one instance bear and how scalable it is. We tested how much time would a method run in a physical Android device and in a cloud instance. We deployed CyanogenMod and Dalvik for a single instance. We used Tsung for stress testing. For those tests we also made a Tomcat server on Dalvik instance that would take the incoming file, the file would be compiled with java and its class file would be wrapped into dex, a Dalvik executable file, that is later executed with Dalvik. Three instances made a Tsung cluster that sent load to a Dalvik Virtual Machine instance. For scaling we used Amazon Auto Scaling tool and Elastic Load Balancer that divided incoming load between the instances
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