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From the technological perspective a portal is a dynamic Web page that consists of pluggable modules, called portlets. These portlets run in a portlet container. The container performs basic functionalities such as management of system resources and authenticating users, while portlets generate the actual Web interface. Portal developers realized that reusability of portlets is a key to the customizability of portals, and the interoperability of portlets across different container platforms in an important step towards this. Around 2001 the Java Specification Request (JSR) 168 emerged as a standard that allows portal developers, administrators and consumers to integrate standards-based portals and portlets across a variety of portal containers. Most of current science gateways are built from JSR-168 compliant portlets and provide easily customizable and reusable solutions for various purposes.

Grid portal examples

The usefulness of Grid portal technologies for computational science has been established by the number of portals being developed in Europe, the United States and Asia. In Europe the most relevant portal developer consortiums have gathered around the Enabling Grids for E-sciencE project (EGEE) and its national Grid counterparts. Some of these portals provide tools that are independent from scientific disciplines, others emphasize solutions that specific communities are familiar with and can utilize efficiently.

P-GRADE Portal provides facilities to create and execute computational simulations on cluster based Grids. Various user communities of the EGEE Grid and several European national Grids apply P-GRADE Portal as a graphical front-end to manage workflow applications on their infrastructures. While P-GRADE Portal is primarily a generic environment, it can be customized to any scientific domain by generating application specific portals from it that grants access only to pre-defined, domain specific workflows and simulations.

The NGS Applications Repository is an open access portal used to describe and list applications and their associated artefacts that are available on the National Grid Service (NGS) of the UK. Applications hosted by the repository are described using middleware agnostic documents, which can be searched for by categories of interest. The repository currently holds over 50 applications from various fields such as bioinformatics, engineering, chemistry, astrophysics or image analysis.

Outlook

The concept of content aggregation seems to still gain momentum and portal solution will likely continue to evolve significantly over the next few years. The Gartner Group recently predicted to expand on the Business Mashups concept of delivering a variety of information, tools, applications and access points through a single mechanism. Mashups are Web applications that combine data or functionality from two or more sources into a single integrated application. The term mashup implies easy, fast integration, frequently done by access to open programming interfaces and data sources to produce results that were not the original reason for producing the raw source data. An example of a mashup is the use of cartographic data from Google Maps to add location information to real estate data, thereby creating a new and distinct Web service that was not originally provided by either source.

Programmers of Grid and high performance computing portals still often find it hard to bridge between user friendly Web interfaces and low-level services of Grid middleware. Errors and faults sent back from the Grid are often difficult to interpret and deal with automatically, meanwhile it is inevitable that easy to use and autonomous portals are important tools to attract larger user communities to Grids. Grid portals will definitely improve in the near future in this respect.

References

  • M. Thomas, J Burruss, L Cinquini, G Fox, D. Gannon, I. Glilbert, G. von Laszewski, K. Jackson, D. Middleton, R. Moore, M. Pierce, B. Plale, A. Rajasekar, R. Regno, E. Roberts, D. Schissel, A. Seth, and W. Schroeder. Grid Portal Architectures for Scientific Applications. Journal of Physics, 16, pp 596-600. 2005.
  • “Web portal” entry in Wikipedia: (External Link) , last accessed 06/06/2009
  • Enabling Grids for E-sciencE project (EGEE): (External Link)
  • P. Kacsuk and G. Sipos: Multi-Grid, Multi-User Workflows in the P-GRADE Portal Journal of Grid Computing, Vol. 3, No. 3-4, Springer Publishers, pp. 221-238, 2005.
  • NGS Job Submission Portal: (External Link) , last accessed: 06/06/2009
  • “Mashup” entry in Wikipedia: (External Link) , last accessed 06/06/2009

Questions & Answers

Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
Kate Reply
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Kate Reply
what is the change in momentum of a body?
Eunice Reply
what is a capacitor?
Raymond Reply
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
Maria Reply
please solve
Sharon
8m/s²
Aishat
What is Thermodynamics
Muordit
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
Saheed Reply
50 m/s due south east
Someone
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
Ramon Reply
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
Someone
definitely of physics
Haryormhidey Reply
how many start and codon
Esrael Reply
what is field
Felix Reply
physics, biology and chemistry this is my Field
ALIYU
field is a region of space under the influence of some physical properties
Collete
what is ogarnic chemistry
WISDOM Reply
determine the slope giving that 3y+ 2x-14=0
WISDOM
Another formula for Acceleration
Belty Reply
a=v/t. a=f/m a
IHUMA
innocent
Adah
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
Nassze Reply
how do lnternal energy measures
Esrael
Two bodies attract each other electrically. Do they both have to be charged? Answer the same question if the bodies repel one another.
JALLAH Reply
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you. Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Robert
like charges repel while unlike charges atttact
Raymond
What is specific heat capacity
Destiny Reply
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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Source:  OpenStax, Research in a connected world. OpenStax CNX. Nov 22, 2009 Download for free at http://cnx.org/content/col10677/1.12
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