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Abstracts:
Keynote:
Web Services for building Scientific Applications - Searching for White Dwarfs,
Savas Parastatidis
The Web Services Grid Application Framework (WS-GAF) project (Jan 2004
- Jan 2005) aimed to demonstrate the value of using standard,
widely-accepted, well-supported Web Services technologies for
scientific and commercial Internet-scale (a.k.a. "Grid") applications.
The scientific application developed is a tool aimed at astronomers who
wish to combine and analyse information from the SuperCOSMOS (UK) and
Sloan Digital Sky Survey (US) scientific archives. This presentation
will discuss the WS-GAF approach to building Internet-scale
applications, the steps followed in creating a tool for scientists, and
the implementation challenges and solutions.
GridAssist, a User Friendly Grid-based Workflow Management Tool,
Mark ter Linden, Hans de Wolf, Ruud Grim
This paper describes GridAssist, a user friendly Grid-based workflow
management tool that allows users to execute workflows in a Grid
environment and hides the underlying technology. Two cases are
described where this tool is now being used: processing of astronomy
data and processing of Earth Observation data.
Web Services Composition for Distributed Data Mining,
Ali Shaikh Ali, Omer F. Rana and Ian J. Taylor
A Web Services-based toolkit for supporting distributed data mining is
presented. A workflow engine is provided within the toolkit to enable a
user to compose Web Services to implement particular point solutions.
Three types of Web Services are provided to implement data mining
functions: (1) classifiers, (2) clustering algorithms, and (3)
association rules. Additional capability is made available through
GNUPlot and Mathematica to enable visualisation of the output. Data
sets may be read from the local filespace, or streamed from a remote
location (provided the algorithm being used has support for streaming).
Two case studies are presented to illustrate the use of the toolkit.
Matchmaking, Datasets and Physics Analysis,
Heinz Stockinger, Flavia Donno, Giulio Eulisse, Mirco Mazzucato,
Conrad Steenberg
Grid enabled physics analysis requires aWorkload Management
System (WMS) that takes care of finding suitable
computing resources to execute data intensive jobs. A typical
example is the WMS available in the LCG2 (also referred
to as EGEE-0) software system, used by several scientific
experiments. Like many other current Grid systems,
LCG2 provides a file level granularity for accessing and
analysing data. However, application scientists such as
High Energy Physicists often require a higher abstraction
level for accessing data, i.e. they prefer to use datasets
rather than files in their physics analysis.
We have improved the current WMS (in particular the
Matchmaker) to allow physicists to express their analysis
job requirements in terms of datasets. This required modifications
to the WMS and its interface to potential data catalogues.
As a result, we propose a simple Data Location Interface
that is based on a web service approach and allows
for interoperability of the WMS with new dataset and file
catalogues. We took a particular High Energy Physics experiment
as the source for our study and show that physics
analysis can be improved by our modifications to the current
Grid system.
How to Run Scientific Applications Over Web Services,
Diego Puppin, Nicola Tonellotto, and Domenico Laforenza
Today, the task of running and coordinating a scientific application
across several administrative domains is extremely complex. As an
example, the most popular tool for scientific applications, MPI, is not
designed to address firewall limitations or data heterogeneity, even if
its extensions deal with some of these problems.
In this paper, we design a new approach to run a scientific application
in a distributed environment, when data and computing power are
scattered across the Web: Web Services can be used to tunnel computation
and data migration.
We show that a very simple mapping exists between MPI primitives and
the Web Service infrastructure. We are currently designing a framework,
based on Web Services, which will implement the main MPI primitives:
this way an MPI application could be run on any platform supporting
Web Services.
Heterogeneous Relational Databases for a Grid-enabled Analysis Environment,
Arshad Ali, Ashiq Anjum, Tahir Azim, Julian Bunn, Saima Iqbal, Richard
McClatchey, Harvey Newman, S. Yousaf Shah, Tony Solomonides, Conrad
Steenberg, Michael Thomas, Frank van Lingen, Ian Willers
Grid based systems require a database access
mechanism that can provide seamless
homogeneous access to the requested data
through a virtual data access system, i.e. a
system which can take care of tracking the data
that is stored in geographically distributed
heterogeneous databases. This system provides
an integrated view of the data that is stored in
the different repositories by using a virtual data
access mechanism, i.e. a mechanism that can
hide the heterogeneity of the backend databases
from the client applications.
This paper focuses on accessing the data which
is stored in disparate relational databases
through a web service interface and exploits the
state-of-the-art features of a Data Warehouse
and Data Marts. We present a middleware that
enables applications to access data that is stored
in geographically distributed relational
databases without being aware of their physical
locations and underlying schema. A web service
interface is provided to enable applications to
access this middleware in a language and
platform independent way. A plug-in for the Java
Analysis Studio (JAS) was developed to submit
complex queries for accessing the data and
visualizing the retrieved results as histograms. A
prototype implementation was created based on
Clarens [4], Unity [7] and POOL [8]. Intensive
tests were carried out against the proposed
features of the middleware. This ability to access
the data stored in the distributed relational
databases transparently is likely to be a very
powerful one for Grid users, especially for the
scientific community wishing to collate and
analyze data distributed over the Grid.
The Clarens Web Service Framework for Distributed Scientific Analysis
in Grid Projects,
Frank van Lingen, Conrad Steenberg, Michael Thomas, Ashiq Anjum, Tahir
Azim, Harvey Newman, Arshad Ali , Julian Bunn, Iosif Legrand
Large scientific collaborations are moving towards service oriented
architectures for implementation and deployment of globally distributed
systems. Clarens is a light weight, high performance, easy to deploy
web service framework that supports the construction of such globally
distributed systems. This article discusses some of the core
functionality of Clarens that the authors believe is important for
building distributed systems, and how Clarens is used within several
projects aimed at supporting scientific analysis for large
collaborations.
Resource Management Services for a Grid Analysis Environment,
Arshad Ali, Ashiq Anjum, Tahir Azim, Julian Bunn, Atif Mehmood, Richard
McClatchey, Harvey Newman, Waqas ur Rehman, Conrad Steenberg, Michael
Thomas, Frank van Lingen, Ian Willers, Muhammad Adeel Zafar
Selecting optimal resources for submitting jobs on a computational Grid
or accessing data from a data grid is one of the most important tasks
of any Grid middleware. Most modern Grid software today satisfies this
responsibility and gives a best-effort performance to solve this
problem. Almost all decisions regarding scheduling and data access are
made by the software automatically, giving users little or no control
over the entire process, and disregarding any user preferences. To
solve this problem, a more interactive set of services and middleware
is desired that provides users more information about Grid weather, and
gives them more control over the decision making process. This paper
presents a set of services that have been developed to provide more
interactive resource management capabilities within the Grid Analysis
Environment (GAE) being developed collaboratively by Caltech, NUST and
several other institutes. These include a steering service, a job
monitoring service and an estimation service that have been designed
and written on top of a common Grid-enabled Web Services framework
named Clarens. The paper also presents a performance analysis of the
developed services to show that they have indeed resulted in a more
interactive and powerful system for user-centric Grid-enabled physics
analysis.
Flexible Authentication and Authorization Architecture for Grid Computing,
Hyunjoon Jung, Hyuck Han, Hyungsoo Jung, Heon Y. Yeom
The Globus Toolkit makes it very easy and comfortable for grid users to
develop and deploy grid services. As for the security mechanism, however,
only static authentication and coarse-grained authorization mechanism is
provided in current Globus Toolkit. In this paper we address the
limitations of current security mechanism in the Globus Toolkit and
propose a new architecture which provides fine-grained and flexible
security mechanism. To implement this without modifying existing
components, we make use of the Aspect-Oriented Programming technique.
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