7,199 research outputs found
A Monitoring System for the BaBar INFN Computing Cluster
Monitoring large clusters is a challenging problem. It is necessary to
observe a large quantity of devices with a reasonably short delay between
consecutive observations. The set of monitored devices may include PCs, network
switches, tape libraries and other equipments. The monitoring activity should
not impact the performances of the system. In this paper we present PerfMC, a
monitoring system for large clusters. PerfMC is driven by an XML configuration
file, and uses the Simple Network Management Protocol (SNMP) for data
collection. SNMP is a standard protocol implemented by many networked
equipments, so the tool can be used to monitor a wide range of devices. System
administrators can display informations on the status of each device by
connecting to a WEB server embedded in PerfMC. The WEB server can produce
graphs showing the value of different monitored quantities as a function of
time; it can also produce arbitrary XML pages by applying XSL Transformations
to an internal XML representation of the cluster's status. XSL Transformations
may be used to produce HTML pages which can be displayed by ordinary WEB
browsers. PerfMC aims at being relatively easy to configure and operate, and
highly efficient. It is currently being used to monitor the Italian
Reprocessing farm for the BaBar experiment, which is made of about 200 dual-CPU
Linux machines.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 10 pages, LaTeX, 4 eps figures. PSN
MOET00
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A modular access control architecture for the Earth system grid federation
ImageJ2: ImageJ for the next generation of scientific image data
ImageJ is an image analysis program extensively used in the biological
sciences and beyond. Due to its ease of use, recordable macro language, and
extensible plug-in architecture, ImageJ enjoys contributions from
non-programmers, amateur programmers, and professional developers alike.
Enabling such a diversity of contributors has resulted in a large community
that spans the biological and physical sciences. However, a rapidly growing
user base, diverging plugin suites, and technical limitations have revealed a
clear need for a concerted software engineering effort to support emerging
imaging paradigms, to ensure the software's ability to handle the requirements
of modern science. Due to these new and emerging challenges in scientific
imaging, ImageJ is at a critical development crossroads.
We present ImageJ2, a total redesign of ImageJ offering a host of new
functionality. It separates concerns, fully decoupling the data model from the
user interface. It emphasizes integration with external applications to
maximize interoperability. Its robust new plugin framework allows everything
from image formats, to scripting languages, to visualization to be extended by
the community. The redesigned data model supports arbitrarily large,
N-dimensional datasets, which are increasingly common in modern image
acquisition. Despite the scope of these changes, backwards compatibility is
maintained such that this new functionality can be seamlessly integrated with
the classic ImageJ interface, allowing users and developers to migrate to these
new methods at their own pace. ImageJ2 provides a framework engineered for
flexibility, intended to support these requirements as well as accommodate
future needs
SWI-Prolog and the Web
Where Prolog is commonly seen as a component in a Web application that is
either embedded or communicates using a proprietary protocol, we propose an
architecture where Prolog communicates to other components in a Web application
using the standard HTTP protocol. By avoiding embedding in external Web servers
development and deployment become much easier. To support this architecture, in
addition to the transfer protocol, we must also support parsing, representing
and generating the key Web document types such as HTML, XML and RDF.
This paper motivates the design decisions in the libraries and extensions to
Prolog for handling Web documents and protocols. The design has been guided by
the requirement to handle large documents efficiently. The described libraries
support a wide range of Web applications ranging from HTML and XML documents to
Semantic Web RDF processing.
To appear in Theory and Practice of Logic Programming (TPLP)Comment: 31 pages, 24 figures and 2 tables. To appear in Theory and Practice
of Logic Programming (TPLP
Institutional Repositories: Features, Architecture, Design and Implementation Technologies
Europe is the leading continent in terms of active adoption and use of Digital Libraries – particularly Institutional Repositories (IRs). Africa has not done poorly in this area with a steady increase from 19 repositories in 2008 to 46 in January, 2011 but there is need to raise awareness and channel efforts towards making IRs easily accessible to Africans through ubiquitous channels such as hand-helds and mobile devices. This paper reviews the features, architecture, design and implementation technologies of IRs. In addition, it highlights viable research areas that can be pursued by African researchers in the field of Digital Libraries. It also encourages research efforts to focus on areas that will be beneficial to Africa
Iris: an Extensible Application for Building and Analyzing Spectral Energy Distributions
Iris is an extensible application that provides astronomers with a
user-friendly interface capable of ingesting broad-band data from many
different sources in order to build, explore, and model spectral energy
distributions (SEDs). Iris takes advantage of the standards defined by the
International Virtual Observatory Alliance, but hides the technicalities of
such standards by implementing different layers of abstraction on top of them.
Such intermediate layers provide hooks that users and developers can exploit in
order to extend the capabilities provided by Iris. For instance, custom Python
models can be combined in arbitrary ways with the Iris built-in models or with
other custom functions. As such, Iris offers a platform for the development and
integration of SED data, services, and applications, either from the user's
system or from the web. In this paper we describe the built-in features
provided by Iris for building and analyzing SEDs. We also explore in some
detail the Iris framework and software development kit, showing how astronomers
and software developers can plug their code into an integrated SED analysis
environment.Comment: 18 pages, 8 figures, accepted for publication in Astronomy &
Computin
Muppet: MapReduce-Style Processing of Fast Data
MapReduce has emerged as a popular method to process big data. In the past
few years, however, not just big data, but fast data has also exploded in
volume and availability. Examples of such data include sensor data streams, the
Twitter Firehose, and Facebook updates. Numerous applications must process fast
data. Can we provide a MapReduce-style framework so that developers can quickly
write such applications and execute them over a cluster of machines, to achieve
low latency and high scalability? In this paper we report on our investigation
of this question, as carried out at Kosmix and WalmartLabs. We describe
MapUpdate, a framework like MapReduce, but specifically developed for fast
data. We describe Muppet, our implementation of MapUpdate. Throughout the
description we highlight the key challenges, argue why MapReduce is not well
suited to address them, and briefly describe our current solutions. Finally, we
describe our experience and lessons learned with Muppet, which has been used
extensively at Kosmix and WalmartLabs to power a broad range of applications in
social media and e-commerce.Comment: VLDB201
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