794 research outputs found
HotGrid: Graduated Access to Grid-based Science Gateways
We describe the idea of a Science Gateway, an application-specific task wrapped as a web service, and some examples of these that are being implemented on the US TeraGrid cyberinfrastructure. We also describe HotGrid, a means of providing simple, immediate access to the Grid through one of these gateways, which we hope will broaden the use of the Grid, drawing in a wide community of users. The secondary purpose of HotGrid is to acclimate a science community to the concepts of certificate use. Our system provides these weakly authenticated users with immediate power to use the Grid resources for science, but without the dangerous power of running arbitrary code. We describe the implementation of these Science Gateways with the Clarens secure web server
Object Database Scalability for Scientific Workloads
We describe the PetaByte-scale computing challenges posed by the next generation of particle physics experiments, due to start operation in 2005. The computing models adopted by the experiments call for systems capable of handling sustained data acquisition rates of at least 100 MBytes/second into an Object Database, which will have to handle several PetaBytes of accumulated data per year. The systems will be used to schedule CPU intensive reconstruction and analysis tasks on the highly complex physics Object data which need then be served to clients located at universities and laboratories worldwide. We report on measurements with a prototype system that makes use of a 256 CPU HP Exemplar X Class machine running the Objectivity/DB database. Our results show excellent scalability for up to 240 simultaneous database clients, and aggregate I/O rates exceeding 150 Mbytes/second, indicating the viability of the computing models
The Clarens web services architecture
Clarens is a uniquely flexible web services infrastructure providing a
unified access protocol to a diverse set of functions useful to the HEP
community. It uses the standard HTTP protocol combined with application layer,
certificate based authentication to provide single sign-on to individuals,
organizations and hosts, with fine-grained access control to services, files
and virtual organization (VO) management. This contribution describes the
server functionality, while client applications are described in a subsequent
talk.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, LaTeX, 4 figures, PSN
MONT00
Distributed Heterogeneous Relational Data Warehouse In A Grid Environment
This paper examines how a "Distributed Heterogeneous Relational Data
Warehouse" can be integrated in a Grid environment that will provide physicists
with efficient access to large and small object collections drawn from
databases at multiple sites. This paper investigates the requirements of
Grid-enabling such a warehouse, and explores how these requirements may be met
by extensions to existing Grid middleware. We present initial results obtained
with a working prototype warehouse of this kind using both SQLServer and
Oracle9i, where a Grid-enabled web-services interface makes it easier for
web-applications to access the distributed contents of the databases securely.
Based on the success of the prototype, we proposes a framework for using
heterogeneous relational data warehouse through the web-service interface and
create a single "Virtual Database System" for users. The ability to
transparently access data in this way, as shown in prototype, is likely to be a
very powerful facility for HENP and other grid users wishing to collate and
analyze information distributed over Grid.Comment: 4 pages, 6 figure
Clarens Client and Server Applications
Several applications have been implemented with access via the Clarens web
service infrastructure, including virtual organization management, JetMET
physics data analysis using relational databases, and Storage Resource Broker
(SRB) access. This functionality is accessible transparently from Python
scripts, the Root analysis framework and from Java applications and browser
applets.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 4 pages, LaTeX, no figures, PSN
TUCT00
Computational experiments with a three-dimensional model of the Cochlea
We present results from a series of compute-intensive simulation experiments employing a realistic and detailed three-dimensional model of the human cochlear macro-mechanics. Our model uses the immersed boundary method to compute the fluid-structure interactions within the cochlea. It is a three-dimensional model based on an accurate cochlear geometry obtained from physical measurements. It includes detailed descriptions of the elastic material components immersed in the fluid, and is based on the previously developed immersed boundary method for elastic shells. The basilar membrane is modeled by a fourth-order partial differential equation of shell theory. The results reproduce the basic well known characteristics of cochlear mechanics and constitute a successful initial step in model validation
The Clarens Web Service Framework for Distributed Scientific Analysis in Grid Projects
Large scientific collaborations are moving towards service oriented architecutres for implementation and deployment of globally distributed systems. Clarens is a high performance, easy to deploy Web Service framework that supports the construction of such globally distributed systems. This paper discusses some of the core functionality of Clarens that the authors believe is important for building distributed systems based on Web Services that support scientific analysis
Job Monitoring in an Interactive Grid Analysis Environment
The grid is emerging as a great computational resource but
its dynamic behavior makes the Grid environment unpredictable. Systems and networks can fail, and the
introduction of more users can result in resource starvation.
Once a job has been submitted for execution on the grid,
monitoring becomes essential for a user to see that the job is completed in an efficient way, and to detect any problems
that occur while the job is running. In current environments
once a user submits a job he loses direct control over the job and the system behaves like a batch system: the user
submits the job and later gets a result back. The only
information a user can obtain about a job is whether it is
scheduled, running, cancelled or finished. Today users are
becoming increasingly interested in such analysis grid
environments in which they can check the progress of the
job, obtain intermediate results, terminate the job based on
the progress of job or intermediate results, steer the job to
other nodes to achieve better performance and check the
resources consumed by the job. In order to fulfill their
requirements of interactivity a mechanism is needed that
can provide the user with real time access to information
about different attributes of a job. In this paper we present
the design of a Job Monitoring Service, a web service that
will provide interactive remote job monitoring by allowing
users to access different attributes of a job once it has been submitted to the interactive Grid Analysis Environment
Community Seismic Network: A Dense Array to Sense Earthquake Strong Motion
The Community Seismic Network (CSN) is currently a 500âelement strongâmotion network located in the Los Angeles area of California (see Fig. 1). The sensors in the network are lowâcost microelectromechanical (MEM) accelerometers that are capable of recording on scale up to accelerations of ±2g. The primary product of the network is a set of measurements of ground shaking in the seconds following a major earthquake. An example of this is shown in Figure 2. The shaking information will be contributed to U.S. Geological Survey products such as ShakeMap (Wald et al., 1999) and ShakeCast (Wald et al., 2006), with the goal of providing first responders a proxy for damage that can guide efforts immediately following the event. The basic premise is the strong groundâmotion shaking varies on a subkilometer scale, which will require a dense network to meaningfully measure the shaking. Evidence for this comes from earthquakes recorded by dense oil company surveys in the Los Angeles area (Clayton et al., 2011)
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