Introduction to EXPReS - Beyond production e-VLBI services T. Charles Yun Program Manager EXPReS Project, JIVE.

Introduction to EXPReS- Beyond production e-VLBI services

T. Charles YunProgram Manager EXPReS Project, JIVE

2006 November 21 IST 2006- Helsinki, Finland Slide #: 2

Presentation Overview• Introductions:

• EXPReS• VLBI• Correlation (analysis)

• Some lessons and thoughts


What is EXPReS?• EXPReS = Express Production Real-time e-VLBI Service

The overall objective of EXPReS is to create a production-level, real-time, “electronic” VLBI (e-VLBI) service, in which the radio telescopes are reliably connected to the central supercomputer at JIVE in the Netherlands, via a high-speed optical-fibre communication network...

- or -

Make e-VLBI routine, reliable and realistic for astronomers

Introduction to EXPReS


EXPReS Details• EXPReS is made possible by the European Commission (DG-

INFSO), Sixth Framework Programme, Contract #026642

• Project Details• Three year, started March 2006• International collaboration• Funded at 3.9 million EUR

• Means: high-speed communication networks operating in real-time and connecting some of the largest and most sensitive radio telescopes on the planet



Activities in EXPReS• Networking Activities

• NA1: Management of I3• NA2: EVN-NREN Forum • NA3: e-VLBI Science Forum • NA4: e-VLBI Outreach, Dissemination & Communications

• Specific Service Activities• SA1: Production e-VLBI Service • SA2: Network Provision for a Global e-VLBI Array

• Joint Research Activities• JRA1: Future Arrays of Broadband Radio Telescopes on

Internet Computing



EXPReS Partners• Joint Institute for VLBI in Europe (coordinator), the

Netherlands• AARNET Pty Ltd., Australia• ASTRON, the Netherlands• Centro Nacional de Informacion Geografica, Spain• Chalmers Tekniska Hoegskola Aktiebolag, Sweden• Commonwealth Scientific and Industrial Research

Organization (CSIRO), Australia• Cornell University, USA• Delivery of Advanced Network Technology to

Europe Ltd. (DANTE), UK• Instituto Nazionale di Astrofisica, Italy• Instytut Chemii Bioorganicznej PAN, Poland• Max Planck Gesellschaft zur Foerderung der

Wissenschaften e.V., Germany• National Research Foundation, South Africa• Shanghai Astronomical Observatory, Chinese

Academy of Sciences, China• SURFNet b.v., The Netherlands• Teknillinen Korkeakoulu, Finland• The University of Manchester, UK• Universidad de Concepcion, Chile• Uniwersytet Mikolaja Kopernika, Poland• Ventspils Augstskola, Latvia



Primer- VLBI• A radio telescope looks at an object in the sky and collects data

to create an “image” of the source• Multiple telescopes can view the same object. The distance

between the telescopes is the baseline. The baseline can be compared to building a single telescope with the diameter of this distance (sort of).

• The resolution increases with additional telescopes and longer baselines

• Correlation is the process by which data from multiple telescopes is collected and processed to create a more accurate image. The correlator a super computer (interferometry)

• The sensitivity of the image increases with the data collection rate at the telescope

Introduction to VLBI


Once upon a time...• Telescopes collected data on

tapes… heavy and bulky… postal mail… once all the tapes arrived… tapes were lost/damaged… hard drive arrays slightly improved the situation...

• It was not unusual for the time between experiment to the beginning of correlation to be multiple weeks.

• Today, you can transport the data over the network:e-VLBI - electronic VLBI



Why transport data over the network?• Using the network to transport

data improves science• Eliminating the need to move

physical objects enables:• Real time analysis• Ability to identify minor

problems in data collection • Hybrid observations• Responsiveness to transient

events• Automated observation

(hands-off observing)• Networked data supports flexible

analysis



Primer- Correlation (Analysis)• Synthesis imaging simulates a very large telescope by measuring

Fourier components of sky brightness on each baseline pair• EVN MkIV data processor at JIVE

• custom silicon, 1024 chips• Input data is 1 Gb/s max• Around 100 T-operations/sec

• Dedicated, purpose designed/built hardware

Introduction to Correlation


Once upon a time…• Cost to build correlator…

limited flexibility (majority of computation in custom hardware)… preset data input rates… scheduling of scarce resource (correlator)… upgrade cost forces longer life-cycle than desired



Why “Grid-ify” correlation?• Grid computing offers promising

possibilities:• keep up with input (e.g.,

LOFAR on BlueGene)• Higher precision and new

applications• Better sensitivity,

interference mitigation, spacecraft navigation

• Can CPU cycles be found on the Grid?

• From 16 antenna @ 1Gb/s (eVLBI) To 1000s at 100 Gb/s (SKA)



Lessons LearnedEach of these bullets is a set of papers, posters and presentations in and of itself…

• Networking is coordination• EXPReS participants on 6 continents

• Connectivity• Networking assumes connectivity, Last mile issues

• Saturating the network is hard• End host hardware• End-to-end Network optimization

• Designing new applications• Custom software- operational vs. proof of concept • Flexible solutions- address current problems, future needs

Reflection.


Looking Forward• Much has been done before

• Importance of standards, open source• Look at other leaders in the field

• Collaboration• Working across disciplines, continents• Partnering to fill gaps (e.g., cpu hardware, analysis

algorithms, visualization, network, storage)• Shared investments

Reflection.


Questions/Answers• Contact information

T. Charles YunProject ManagerEXPReS (JIVE)tcyun \at\ jive dot nl

• Additional Informationhttp://expres-eu.org/ [note: only one “s”]http://www.jive.nl/

• EXPReS is made possible through the support of the European Commission (DG-INFSO), Sixth Framework Programme, Contract #026642

Conclusion


Introduction to EXPReS - Beyond production e-VLBI services T. Charles Yun Program Manager EXPReS Project, JIVE.

Documents

vlbi slide

expres slide

expres details expres

electronic vlbi evlbi

electronic vlbi introduction

primer vlbi

correlation slide

evlbi outreach