Below are some links to publications and web applications that I have worked on over the years. Goals Bio Astronomical events and transients Virtual Observatory Digital Data Access Astronomy Cyberinfrastucture and Grids and Clouds Mathematics Parallel Computational Fluid Dynamics Gravitational waves (LIGO) Materials science Nuclear physics and mathematical physics

My work focuses on providing people with meaningful access by people to scientific data, as well as the mining, classification, and preservation of that data. The ultimate objective is enabling automated, intelligent decisions from scientific data.

Scientific data is being created at a great rate -- remote-sensing images of the Earth, high-resolution 3D images of the brain, astrophysical, social science, and ecological data -- but often it seems to be available only to a limited priesthood of professionals in the field, and without the metadata it needs to be useful in the future. Broadening the access will provide a clearer view of the world to those who are interested, whether they are research scientists or schoolchildren. Hence my interest in databases, user interfaces, public access to Government-funded data, and scientific visualization.

Much of this waterfall of data comes from sensors, such as astronomical telescopes, and as the rates increase, it is necessary for automated systems to be able to make decisions quickly and responsibly, often based on incomplete and multi-sourced data, with conflicting interpretations. Finding the most "important" event from many requires comparison of these heterogeneous event portfolios. Hence my interest in Bayesian methods for automated decision.

Often new discoveries come about through cross-fertilization: comparison and cross-correlation between very different information sources. If this kind of activity is to happen with scientific databases, we must tackle to difficult activity that has come to be known as "federation": making one sophisticated, stand-alone software system interoperate with another. Taking a known, evolved, trusted database or program, with its own ways of communication to the outside world, and changing and supplementing those enough so that the software can work with another database or program.

For the future, I am interested in Bayesian methods for combining multiple classifiers, classification from multi-sourced data, comparing classifications with heterogeneous data, and decisions that are time-sensitive and costly. I am also interested in building a robust international infrastructure for dissemination and automated classification of high-throughput event streams.

Skyalert: authoring, dissemination, annotating, mining, and messaging of immediate astronomical events. http://skyalert.org. 2009 - present.

VOEventNet: Dissemination of event packets via International Backbone R.D. Williams, A.J. Drake, M.J. Graham et al Click here.

Transient Event Notification with VOEvent
Williams, R.D.; Seaman, R.L.
in The National Virtual Observatory: Tools and Techniques for Astronomical Research eds. Graham M.J., Fitzpatrick M.F., McGlynn T.A. ASP Conference Proceedings 382 (2007). PDF

VOEventNet: An Open Source of Transient Alerts for Astronomers Data warehouse for Catalina Real-time Transient Survey, Palomar-Quest, NASA/GCN events. 2005 - present A.J. Drake and R.D. Williams. Click here.

Astronomical network event and observation notification
White R.R., Allan A., Barthelmy S., Bloom J., Graham M.J., Hessman F.V., Marka S., Rots A., Scholberg K., Seaman R., Stoughton C., Vestrand W.T., Williams R., Wozniak P.R.,
Astronomische Nachrichten, 327 (2006) 775.

Sky Event Reporting Metadata (VOEvent) R. Seaman, R.D. Williams, A. Allan, S. Barthelmy, J. Bloom, M. Graham, F. Hessman, S. Marka, A. Rots, C. Stoughton, T. Vestrand, R. White, P. Wozniak, A Recommendation of the International Virtual Observatory Alliance, 2006. HTML

Transient Event Reporting and Response with VOEvent
Seaman, R.; Allan, A.; Williams, R.
Astronomical Data Analysis Software and Systems ASP Conference Series, Vol. 394, Eds R.W. Argyle, P.S. Bunclark, and J.R. Lewis., p.213 (2007) PDF

Google Sky mashup Roy Williams and Andrew Drake Real-time display of events from multiple streams. 2007. (bring up the Google Earth/Sky client, click Current Sky Events and VOEventNet)., or click here.

Worldwide Telescope mashup Roy Williams Real-time display of events from multiple streams, 2009. Click here (use Safari or IE).

Automated probabilistic classification of transients and variables
Mahabal, A., Djorgovski, S. G.; Turmon, M., Jewell, J.; Williams, R. D.; Drake, A. J.; Graham, M. G.; Donalek, C.; Glikman, E.
Astron. Nacht. 329 (2008) 288

New Approaches to Object Classification in Synoptic Sky Surveys
Donalek C., Mahabal A., Djorgovski S.G., Marney S., Drake A., Glikman E., Graham M.J., Williams R.
in Classification and Discovery in Large Astronomical Surveys. AIP Conference Proceedings, Vol. 1082, p. 252

Towards Real-time Classification of Astronomical Transients
Mahabal A., Djorgovski S.G., Williams R., Drake A., Donalek C., Graham M.J., Moghaddam B., Turmon M., Jewell J., Khosla A., Hensley B.
in Classification and Discovery in Large Astronomical Surveys. AIP Conference Proceedings, Vol. 1082, p. 287.

Palomar-QUEST: A case study in designing sky surveys in the VO era
Matthew J. Graham, Roy Williams, S. G. Djorgovski, Ashish Mahabal, Charles Baltay, Dave Rabinowitz, Anne Bauer, Jeff Snyder, Nick Morgan, Peter Andrews, Alexander S Szalay, Robert J. Brunner and Jim Musser
Astronomical Data Analysis Software & Systems XIV, 24 - 27 October, 2004, Pasadena, California. PDF

Exploring the Time Domain with the Palomar-QUEST Sky Survey
A. Mahabal, S.G. Djorgovski, M. Graham, R. Williams, B. Granett, M. Bogosavljevic, C. Baltay, D. Rabinowitz, A. Bauer, P. Andrews, N. Morgan, J. Snyder, N. Ellman, S. Duffau, J. Musser, S. Mufson, M. Gebhard, R. Brunner.
Astronomical Data Analysis Software & Systems XIV, 24 - 27 October, 2004, Pasadena, California. PDF

Time Domain Explorations With Digital Sky Surveys
Ashish A. Mahabal, S. G. Djorgovski, M. J. Graham, Priya Kollipara, Benjamin Granett, Elisabeth Krause, Roy Williams, M. Bogosavljevic, C. Baltay, D. Rabinowitz, A. Bauer, P. Andrews, N. Ellman.
Astronomical Data Analysis Software and Systems XIV. Astronomical Society of the Pacific Conference Series. Astronomical Society of the Pacific, San Francisco, CA, P2.2.7.

VIM: Visual Integration and Mining Integrate data from multiple positions and datasets. Click here

National Virtual Observatory Summer School 2008 Roy Williams, Faculty Chair Organized the content and teaching for a two-week intensive course on the Virtual Observatory, September 2008, Santa Fe, New Mexico. Details here.

Describing Data and Data Collections in the VO
Kent, B.R.; Hanisch, R.J.; Williams, R.D.
in The National Virtual Observatory: Tools and Techniques for Astronomical Research, eds. Graham M.J., Fitzpatrick M.F., McGlynn T.A. ASP Conference Proceedings, vol. 382. PDF

VOTable Format Definition François Ochsenbein, Roy Williams, Clive Davenhall, Daniel Durand, Pierre Fernique, David Giaretta, Robert Hanisch, Tom McGlynn, Alex Szalay, Mark B. Taylor, Andreas Wicenec, A Recommendation of the International Virtual Observatory Alliance. HTML

An IVOA Standard for Unified Content Descriptors S. Derriere, N. Gray, R. Mann, A. Preite Martinez, J. McDowell, T. Mc Glynn, F. Ochsenbein, P. Osuna, G. Rixon, R.D. Williams. A Recommendation of the International Virtual Observatory Alliance. HTML

Virtual Observatory: From Concept to Implementation
S. G. Djorgovski and R. Williams
In: Science with Wavelengths on Human Scales, ASPCS, vol. 3xx. ASPCS PDF

Lectures on Virtual Observatory Astronomy with Large and Complex Data Sets and Trends in e-Science
Roy Williams and George Djorgovski
BRAVO Workshop, Sao Jose dos Campos, Brazil, 2007 Link

The IVOA in 2007: Assessment and Future Roadmap Roy Williams and the IVOA Technical Coordination Group International Virtual Observatory Alliance, PDF

The IVOA in 2006: Assessment and Future Roadmap Roy Williams and the IVOA Technical Coordination Group International Virtual Observatory Alliance, PDF.

The IVOA in 2005: Assessment and Future Roadmap Roy Williams and the IVOA Technical Coordination Group International Virtual Observatory Alliance, PDF

Virtual Observatory Architecture Overview Roy Williams, Bob Hanisch, Tony Linde, Johnathan McDowell, Reagan Moore, François Ochsenbein, Masatoshi Ohishi, Guy Rixon, Alex Szalay, Doug Tody, International Virtual Observatory Alliance, HTML

A Virtual Observatory Vision based on Publishing and Virtual Data
Roy Williams, Reagan Moore, Robert Hanisch. PDF

XML and Web Services for Astronomers
Roy Williams and Robert Brunner
tutorial at ADASS 2002, Baltimore, October 2002. PPT

Grids and the Virtual Observatory Roy Williams in Grid Computing: Making The Global Infrastructure a Reality by Fran Berman, Anthony J.G. Hey, and Geoffrey Fox, Wiley, 2003, pp 837-858. PDF

Approaches to Federation of Astronomical Data Roy Williams in Virtual Observatories of the Future, eds. R. J. Brunner, S. G. Djorgovski, and A. S. Szalay, Astronomical Society of the Pacific, Conference Series 225. November 2000. PDF

Scientific Data Mining Integration and Visualization Bob Mann, Roy Williams, Malcolm Atkinson, Ken Brodlie, Amos Storkey, Chris Williams, report of a workshop held in Edinburgh, 24-25 October 2002. PDF

Report of the European Union - United States Workshop on Large Scientific Databases Roy Williams, Paul Messina, Fabrizio Gagliardi, John Darlington, and Giovanni Aloisio October 1999 html, pdf, text.

Special issue: Interfaces to Scientific Digital Archives
ed. Roy Williams
Future Generation Computer Systems 16 (1): VII-VIII (1999)

Interfaces to Scientific Data Archives
Report of the NSF Workshop
Roy Williams, Julian Bunn, Reagan Moore and James Pool,
May 1998. PDF or HTML.

A High-Performance Active Digital Library
Roy Williams and Bruce Sears
Parallel Computing 24 (12-13): 1709-1711 (1998). PDF

The Digital Puglia Project: An active digital library of remote sensing data G. Aloisio, M. Cafaro, R. Williams Lecture Notes in Computer Science 1593: 563-572 (1999)

Agent based data management in digital libraries
Y.Y. Yang, O.F. Rana, D. W. Walker, R. D. Williams
Parallel Computing 28 (5): 773-792 (2002)

Multi-Wavelength Image Space: Another Grid-Enabled Science
Roy Williams, Bruce Berriman, Ewa Deelman, John Good, Joseph Jacob, Carl Kesselman, Carol Lonsdale, Seb Oliver, Tom Prince
Concurrency & Computation, vol 15 (2003), pp 539-549. PDF,

Object detection in multi-epoch data
G. Jogesh Babu, Ashish Mahabal, S. G. Djorgovski, R. Williams
Statistical Methodology, Volume 5, Issue 4, p. 299-306. PDF

Sub-Saturation Phases of Nuclear Matter
R. D. Williams and S. E. Koonin,
Nucl. Phys. A345, 844 (1984)

Bound-State Decay of Rhenium-187
R. D. Williams, W. A. Fowler and S. E. Koonin,
Astrophys. J. 281, 363 (1984)

Putting your Web Application in the Cloud
Part of a Caltech seminar series, 2009. PDF

Data Intensive Computing in the 21st Century
Guest editors: Ian Gorton, Paul Greenfield, Alex Szalay, Roy Williams
Special issue of IEEE Computer 41 (2008) 41.

Cloudspace: virtual environments in the VO
Graham M.J., Williams R.D. in Astronomical Data Analysis Software and Systems XVII, eds. Lewis J., Argyle R., Bunclarke P., Evans D. & Gonzales-Solares E. ASP Conference Proceedings, San Francisco, p. 73

Programmatic Interfaces—Grid Computing with NESSSI
in The National Virtual Observatory: Tools and Techniques for Astronomical Research. eds. Graham M.J., Fitzpatrick M.F., McGlynn T.A. ASP Conference Proceedings, vol. 382 PDF

HotGrid: Graduated Access to Grid-Based Science Gateways
Williams, R. Steenberg, C. Bunn, J. Lect. Notes Computer Sci. 3470 (2005) 78. PDF

An Architecture for Scaling NVO Services to TeraGrid Roy Williams, Bob Hanisch, Joe Jacob, Ray Plante and Alex Szalay Technical Report. PDF

Web access to supercomputing
G. Aloisio, M. Cafaro, C. Kesselman, R. Williams
Computational Science and Engineering 3 (6): 66-72 (2001)

Grid computing on the web using the globus toolkit
G. Aloisio G, M. Cafaro, P. Falabella, R. Williams
Lecture Notes in Computer Science 1823: 32-40 (2000)

An XML Architecture for High-Performance Web-Based Analysis of Remote-Sensing Archives
Giovanni Aloisio, Giovanni Milillo, and Roy Williams
Future Generation Computing Systems 16 (1): 91-100 NOV 1999. PDF.

Paraflow: A dataflow distributed data-computing system
Roy Williams and Bruce Sears
Lecture Notes in Computer Science 1401: 556-565 (1998)

Metacomputing - From ideas to real implementations
Wolfgang Nagel and Roy Williams
Parallel Computing 24 (12-13): 1709-1711 (1998)

A Distributed Web-based Metacomputing Environment
G. Aloisio, M. Cafaro, P. Messina, R. D. Williams,
in HPCN97, Vienna, April 1997. PDF

Parallel Computing Works! G. C. Fox, R. D. Williams and P. C. Messina, Morgan-Kaufmann, San Francisco, 1994

Benchmarking Advanced Architecture Computers
P. Messina, C. F. Baillie, E. W. Felten, P. G. Hipes, D. W. Walker, R. D. Williams, et al,
Concurrency, 2, 195 (1990)

Video: Letter R formed by evolution of non-uniform Gray-Scott model, 1999. Click here.

The Formation, Structure, and Stability of a Shear Layer in a Fluid with Temperature-Dependent Viscosity
D. J. Estep, S. M. Verduyn Lunel, and R. D. Williams
June 2000
PDF.

Estimating the Error of Numerical Solutions of Systems of Nonlinear Reaction-Diffusion Equations D. J. Estep, M. G. Larsen, and R. D. Williams Memoirs Amer. Math. Soc., 146 (2000) number 696, pp 1-109. PDF

Error Estimation for Numerical Differential Equations
D. J. Estep, S. M. Verduyn Lunel and R. D. Williams
IEEE Antennas and Propagation 38 (2): 71-76 (1996). PDF

Accurate Parallel Integration of Large Sparse Systems of Differential Equations D. J. Estep and R. D. Williams Mathematical Models and Methods in Applied Sciences 6 (4): 535-568 (1996). PDF

A Test Suite for High-Performance Parallel Java
Jochem Hauser, Thorsten Ludewig, Roy Williams, Ralf Winkelmann, Torsten Gollnick, Sharon Brunett, Jean Muylaert
Advances in Engineering Software 31 (8-9): 687-696 (2000)

A Pure Java Parallel Flow Solver Jochem Hauser, Thorsten Ludewig, Torsten Gollnick, Ralf Winkelmann, Roy Williams, Jean Muylaert, and Martin Spel AIAA paper 99-0549, proceedings of 37th Aerospace Sciences Meeting, Reno NV, Jan 1999. PDF.

Strategies for Parallel and Numerical Scalability of CFD Codes Ralf Winkelmann, Jochem Hauser and Roy Williams Computational Methods in Applied Mechanical Engineering. 174 (3-4): 433-456 (1999). PDF (image shows Huygens craft, that landed on Titan Jan 2004)

A Tangled Web Strategy for Numerical and Parallel Scalability in Aerospace Simulation J. Haeuser, R. D. Williams and R. Winkelmann Proceedings of CFD97, University of Victoria, Canada, 25-27 May 1997. PDF.

Efficient Convergence Acceleration for Parallel CFD Codes
R.D. Williams, J. Hauser and R. Winkelmann,
Proceedings of the Parallel CFD '96 conference, Capri, Italy
July 1996. PDF

A Newton-GMRES Method for the Parallel Navier-Stokes Equations
J. Hauser, R.D. Williams, H.-G. Paap, M. Spel, J. Muylaert and R. Winkelmann
Proceedings of the Parallel CFD '95 conference, Pasadena, California
July 1995. PDF

Strategies for Parallelizing a Navier-Stokes Code on the Intel Touchstone Machines
J. Häuser and R. D. Williams,
Int. J. Num. Meth. Fluids 15 (1992) 51. PDF

Adaptive Parallel Meshes with Complex Geometry
R. D. Williams
in Numerical Grid Generation for Computational Fluid Dynamics, ed. A.-S. Arcilla et. al., Elsevier North-Holland, Amsterdam, 1991. PDF

Performance of Dynamic Load Balancing Algorithms for Unstructured Mesh Calculations
R. D. Williams,
Concurrency, 3 (1991) 457. PDF

Strategies for Parallelizing a Navier-Stokes Code on the Intel Touchstone Machines
J. Häuser and R. D. Williams,
Int. J. Numerical Methods in Fluids, 15, 51 (1992)

Voxel Databases: A Paradigm for Parallelism with Spatial Structure
R. D. Williams,
Concurrency, 4 (1992) 619. PDF

Adaptive Parallel Meshes with Complex Geometry
C. F. Baillie, R. D. Williams, S. M. Catterall and D. A. Johnston
Nucl. Phys B348, 543 (1991)

Performance of Dynamic Load Balancing Algorithms for Unstructured Mesh Calculations
R. D. Williams,
Concurrency, 3, 457 (1991)

Distributed Irregular Finite Elements
R. D. Williams
in Numerical Methods in Laminar and Turbulent Flow, Pineridge Press, Swansea, UK, 1989, ed C. Taylor,

Supersonic Flow in Parallel with an Unstructured Mesh
R. D. Williams
Concurrency, 1, 51 (1989)

Free-Lagrange Hydrodynamics in Parallel R. D. Williams Parallel Computing 7, 439 (1988)

XSIL: Extensible Scientific Interchange Language Kent Blackburn, Albert Lazzarini, Tom Prince and Roy Williams Lect. Notes. Comp. Sci. 1593 (1999) 513. PDF

Applications of virtual data in the LIGO experiment
Ewa Deelman, Carl Kesselman, Roy Williams, et al.
Lecture Notes in Computer Science 2328: 23-34 2002

A Virtual Data Grid for LIGO
Ewa Deelman, Carl Kesselman, Roy Williams, Albert Lazzarini, Thomas A. Prince, Joe Romano and Bruce Allen
Lecture Notes in Computer Science, vol 2110 (2001) pp 3-12
PDF

Network data analysis server (NDAS) prototype development
Szabi Marka, Benoit Mours, Roy Williams
Classical and Quantum Gravity 19 (7): 1537-1540 (2002)

Analysis of LIGO data for gravitational waves from binary neutron stars
Abbott B, Abbott R, Adhikari R, et al.
Physical Review D 69 (12): art. no. 122001 (2004)

Analysis of first LIGO science data for stochastic gravitational waves
Abbott B, Abbott R, Adhikari R, et al.
Physical Review D 69 (12): art. no. 122004 (2004)

First upper limits from LIGO on gravitational wave bursts
Abbott B, Abbott R, Adhikari R, et al.
Physical Review D 69 (10): art. no. 102001 (2004)

Setting upper limits on the strength of periodic gravitational waves from PSR J1939+2134 using the first science data from the GEO 600 and LIGO detectors
Abbott B, Abbott R, Adhikari R, et al.
Physical Review D 69 (8): art. no. 082004 APR 15 2004

Upper limits on the strength of periodic gravitational waves from PSR J1939+2134
Allen B, Woan G, Abbott B, et al.
Classical and Quantum Gravity 21 (5): S671-S676 (2004)

Two Transitions in Tangentially Anchored Nematic Droplets R. D. Williams J. Phys. A19, 3211 (1986)

Critical Spin Dynamics of Europium Oxide
S. W. Lovesey and R. D. Williams
J. Phys. C19, L253 (1986)

Scattering Response of a Phonon Damped Harmonic Oscillator
R. D. Williams, S. W. Lovesey and W. Renz,
Z. Physik B64, 129 (1986)

Neutron Scattering from a Substitutional Mass Defect
R. D. Williams and S. W. Lovesey
Z. Physik B62, 413 (1986)

The Coupling of Phonons to a Helium Atom Adsorbed on Graphite
R. D. Williams, M. W. Cole and S. E. Koonin,
Phys. Rev. B28, 1076 (1983)

Computational Aspects of Simulating Dynamically Triangulated Random Surfaces
C. F. Baillie, R. D. Williams, D. A. Johnston
Computer Physics Communications 58 (1-2): 105-117 (1990)

Semiclassical Quantization in Many Dimensions
R. D. Williams,
Ph.D. Thesis, California Institute of Technology, 1983

Atomic Final-State Interactions in Tritium Decay
R. D. Williams and S. E. Koonin,
Phys. Rev. C27, 1815 (1983)

Semiclassical Quantization of the Shell Model R. D. Williams and S. E. Koonin, Nucl. Phys. A391, 79 (1982)

Direct Capture Cross Sections at Low Energy
R. D. Williams and S. E. Koonin,
Phys. Rev. C23, 2773 (1981)