Current Teaching and Research

• PSU, CSE 497B, Dynamic Memory Allocation.
• PSU, CSE 411, Operating Systems.
• Rabbit, A Performance Counters Library for Intel/AMD Processors and Linux.

• This page with links:  http://www.cse.psu.edu/~dheller/personal/vita.html

Education

• Carnegie-Mellon University, B.S. (Mathematics), 1971
• Carnegie-Mellon University, Ph.D. (Computer Science), 1977
• Thesis title: Direct and Iterative Methods for Block Tridiagonal Linear Systems
• Thesis advisor: Prof. J.F. Traub
• Summary: numerical analysis of cyclic reduction methods, shown to exhibit quadratic convergence, with application to vector computers

Employment History

• Aug. 2001 - present, Associate Professor of Computer Science and Engineering, Pennsylvania State University, University Park, Pa.
• Aug. 1994 - May 2001, Adjunct Associate Professor of Computer Science, Iowa State University, Ames, Iowa.
• April 1994 - Sept. 2000, Senior Scientist, Scalable Computing Laboratory, Applied Mathematical Sciences, Ames Laboratory, U.S. Dept. of Energy, Ames, Iowa.
• continuing as an Ames Laboratory Associate
• Oct. 1993 - April 1994, Research Scientist, Center for Research on Parallel Computation, Rice University, Houston, Texas.
• March 1983 - Sept. 1993, Staff Research Computer Scientist, Bellaire Research Center, Shell Development Company [Shell Oil Co.], Houston, Texas.
• Service Recognition Awards - Dec. 1986, Aug. 1988
• President's Award for Team Excellence - June 1992
• July 1990 - June 1991, Exchange Scientist, Koninklijke/Shell Exploratie en Produktie Laboratorium, Rijswijk, The Netherlands.
• Dec. 1975 - March 1983, Assistant Professor of Computer Science, The Pennsylvania State University, University Park, Pa.
• summer 1978, Numerical Mathematics Group, Computation Dept., Lawrence Livermore National Laboratory, Livermore, Calif.; Q clearance, lapsed.
• summer 1974, Student Assistant, Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, Hampton, Va.

Research Activity

• Numerical Analysis, Parallel Computation, Computer Architecture (technology-oriented algorithm design and analysis)
• At Shell, simulation, specification, selection and application of parallel computers for geophysics and petroleum reservoir modeling, with emphasis on the nCUBE hypercube system. Operating systems and programming environments for distributed-memory computers.  Assessments of high-performance computers for future applications.
• Part of the original research team that demonstrated to Shell that parallelism was a viable technology for seismic data processing. nCUBE systems were placed into operational use at Shell in Dec. 1987, and have been recognized as an important contributor to the company's exploration community. This is believed to have been the first production use of a parallel computer in a commercial organization.
• At Rice, application of the Fortran D programming language to large-scale geophysical programs, compiler optimization techniques for distributed-memory computers.
• At Ames Lab, programming and debugging support tools for distributed memory systems, performance evaluation and analysis. Computational clusters from commodity components.
• At ISU and PSU, benchmark programs, operating system components and user-level tools for performance measurement and analysis.

Research Publications

• A determinant theorem with applications to parallel algorithms, SIAM J. Numer. Anal., vol. 11 (1974), pp. 559-568.
• On the efficient computation of recurrence relations, ICASE, Hampton, Va.; Computer Science Dept., Carnegie-Mellon Univ., Pittsburgh, Pa., June 1974.
• Some aspects of the cyclic reduction algorithm for block tridiagonal linear systems, SIAM J. Numer. Anal., vol. 13 (1976), pp. 484-496.
• Accelerated iterative methods for the solution of tridiagonal systems on parallel computers, with D.K. Stevenson and J.F. Traub, J. ACM, vol. 23 (1976), pp. 636-654.
• Minimal parallelism for computations under time constraints, in High Speed Computer and Algorithm Organization, D.J. Kuck et al., eds., Academic Press, 1977, pp. 321-322.
• A survey of parallel algorithms in numerical linear algebra, SIAM Review, vol. 20 (1978), pp. 740-777.
• Minimal parallelism for associative computations under time constraints, Computing, vol. 22 (1979), pp. 101-118.
• On-line pipeline systems for recursive numeric computations, with M.J. Irwin, Proc. 7th Symp. on Computer Architecture, May 1980, pp. 292-299.
• Appendix to O. Wing and J.W. Huang, A computation model of parallel solution of linear equations, IEEE Trans. Computers, vol. C-29 (1980), pp. 632-638.
• More counterexamples to the LINPACK condition estimator, Computer Science Dept., Pennsylvania State Univ., July 1981.
• Optimal information for numerical differentiation, Computer Science Dept., Pennsylvania State Univ., Sept. 1981.
• Systolic networks for orthogonal equivalence transformations and their applications, with I.C.F. Ipsen, Proceedings of MIT Conf. on Advanced Research in VLSI, P. Penfield, ed., Artech House, Jan. 1982, pp. 113-122.
• Systolic networks for orthogonal decompositions, with I.C.F. Ipsen, SIAM J. Sci. Stat. Computing, vol. 4 (1983), pp. 261-269.
• Decomposition of recursive filters for linear systolic arrays, Real Time Signal Processing VI, K. Bromley, ed., Proc. SPIE, vol. 431, Aug. 1983, pp. 55-59.
• Multiprocessor Simulation Program SIMON, Shell Development Co., Houston, Nov. 1984.
• Mathematical hardware - design issues and responsibilities, in Algorithmically Specialized Parallel Computers, L. Snyder et al., eds., Academic Press, 1985, pp. 233-241.
• Partitioning big matrices for small systolic arrays, in VLSI and Modern Signal Processing, S.Y. Kung et al., eds., Prentice-Hall, 1985, pp. 185-199.
• Performance Measurements of the nCUBE/ten Multiprocessor, Shell Development Co., Houston, Dec. 1988.
• Ten Steps for Managing Parallel Computing Projects, IEEE Parallel & Distributed Technology, Spring 1994, pp. 6-8.
• Issues of Running Codes on Very Large Parallel Processing Systems, in Debugging and Performance Tuning for Parallel Computing Systems, M.L. Simmons et al., eds., IEEE Computer Society Press, 1996, pp. 233-243.
• A Communication Library Using Active Messages to Improve the Performance of PVM, with K.R. Subramaniam and S.C. Kothari, J. Parallel and Distributed Computing, vol. 39 (1996), pp. 146-152.

Software Distributions

• The nCube system diagnostic programs described in the paper Issues of Running Codes ... are available from http://www.scl.ameslab.gov/Personnel/don/nCubetools/index.html.
• Rabbit, A Performance Counters Library for Intel/AMD Processors and Linux.  User manual and source code available from http://www.scl.ameslab.gov/Projects/Rabbit/index.html.

Shell Development Company, Internal Reports

These cannot be supplied, except as noted above.

• Simulation of Multiprocessor Systems for Geophysical Computing, with W.D. Moorhead, April 1984, 12 pp.
• Multiprocessor Simulation Program SIMON, July 1984, 62 pp. Edited version approved for public release.
• Multiprocessor Calculation of the Minimum-Time Algorithm, with W.D. Moorhead, Sept. 1984, 10 pp.
• Some Examples of Seismic Data Processing on a Panel-Oriented Parallel Computer, with J.S. Danburg and R.F. Starr, Nov. 1984, 12 pp.
• Hypercube Switching Element, March 1985, 9 pp.
• Two-Dimensional Fast Fourier Transforms for Hypercube Multiprocessors, July 1985, 33 pp.
• Experiments with SIMON: Bitonic Sorting on a Hypercube, March 1986, 48 pp.
• Software Technology, with W.S. Rhea, May 1987, 208 pp. A survey of the state-of-the-art in 1986, with projections 5-15 years hence.
• Basic Linear Algebra Subprograms for the nCUBE Node Processor, Dec. 1987, 19 pp.
• A Short Course on Parallel Computing: The nCUBE Programming Environment, Oct. 1988, 60 pp.
• A Tool for Analysis of Message-Passing Bugs on the nCUBE Multiprocessor System, Nov. 1988, 14 pp.
• Performance Measurements of the nCUBE/ten Multiprocessor, Dec. 1988, 28 pp. Edited version approved for public release.
• Production Use of Parallel Computing Within Shell Oil, with 19 co-authors, 1989 Geophysical Conference, Jan. 1989, 26 pp.
• GASSIM on the nCUBE: Application of a Parallel Computer to Reservoir Simulation, 1989 Production Computer Systems Conference, March 1989, 4 pp.
• Parallel Computing Debugging Tools: An Instrumented Operating System for the nCUBE Multiprocessor, Advanced Technology Workshop, Bellaire Research Center, Nov. 1989, 20 pp.
• Software Portability Among Shell's Parallel Computer Systems, KSEPL report, Oct. 1991, 47 pp.
• Intel Parallel Computer Systems, Nov. 1992, 50 pp.
• Fundamental Advice for Management of an Alternative Architecture Project, Sept. 1993, 4 pp.

Shell Development Company, Significant Software Developments

• Simulation studies that led to selection of nCUBE systems for seismic data processing.
• Continual beta-test of nCUBE products, 1985-1993.
• Ported a single-phase reservoir simulator to the nCUBE-1, advised and participated in later efforts by others at BRC and KSEPL.
• Software quality assurance tools for the nCUBE-1 and nCUBE-2; instrumented OS with message-passing bug analyzer, OS data structure scanner, system diagnostics.
• Collaboration with Applied Parallel Research, Inc., for design requirements, specification and testing of the Forge automatic parallelization tool.
• Consultant studies, performance analysis and program modifications for a wide variety of scientific applications.

Invited Lectures at Conferences and Workshops

• A Simulator for Multiprocessor Networks, ARO Workshop, New Computing Environments: Parallel, Vector and Systolic, Stanford Univ., Nov. 7-9, 1984.
• Early Experience with the nCUBE at Shell, Second Conference on Hypercube Multiprocessors, Knoxville, Sept. 29-30, 1986.
• Workshop on Debugging and Performance Tuning for Parallel Computing Systems, Chatham. MA, Oct. 2-5, 1994.  (see above for publication in proceedings)
• Seismic Data Processing Challenges, Workshop on Inverse Problems, Molle, Sweden, June 1995.
• Statistical Variations in Performance Analysis, Gordon Research Conference on High-Performance Computing, Plymouth, MA, Aug. 1997.

Panel Discussions at Conferences

• Hypercube Simulators, First Conference on Hypercube Multiprocessors, Knoxville, Aug. 26-7, 1985.
• Computer Technology and Seismic Modeling Workshop, Soc. Exploration Geophysicists, Houston, Nov. 6, 1986.
• Are advances in supercomputing occurring rapidly enough?, Second Int. Conf. of Supercomputing, Santa Clara, May 5-8, 1987.
• Massively Parallel vs. Parallel Vector Supercomputers: a User's Perspective, Supercomputing '93, Portland, Ore., Nov. 15-19, 1993. (abstract in conference proceedings, pp. 918-20)

Invited Lectures at Universities, etc.

• Sandia Laboratories, Albuquerque, 1979, 1982
• Los Alamos Scientific Laboratory, 1979
• IBM T.J. Watson Research Center, 1981
• University of New Mexico, 1982
• University of Minnesota, 1982
• Rice University, 1983 (IEEE ASSP, Houston chapter)
• Yale University, 1985
• Pennsylvania State University, 1987
• University of Houston, 1988
• University of Texas, Austin, 1988
• Pittsburgh Supercomputing Center, 1992
• David Sarnoff Research Center, 1993
• Oak Ridge National Laboratory, 1994
• Minnesota Project Innovation, 1994
• National Center for Supercomputing Applications, 1998

Gordon Bell Prize selection committee, 1993-4

• Gordon Bell Prize Lectures 1993, Proc. Supercomputing '93, pp. 514-5.
• Summary articles in IEEE Computer, Jan. 1994, pp. 69-75, and Jan. 1995, pp. 68-74.

Shell Training Courses

• Introductory Geology, July 1983 (1 week)
• Univac for Data Processors, Oct. 1983 (1 week)
• Basic Exploration Seismology, April-May 1984 (7 weeks)
• Ph.D. Recruiter Training, Sept. 1984 (4 days)
• Migration Methods and Velocity Models, Dec. 1985 (3 days)
• Migration Methods and Velocity Models, Dec. 1987 (2 days)
• Basic Problem Solving, Jan. 1990 (2 days)
• Communications Workshop, May 1993 (5 days)

Miscellaneous Assignments at Shell

• Computer Technology Review, member of study team, April - November 1986.
• Innumerable internal presentations on current research activities and reviews of conferences attended.
• Representative of Shell Companies Foundation to Univ. of Illinois and Carnegie-Mellon Univ. Computer Science Depts.
• Member of recommendation team for Shell Foundation Distinguished Professor of Computer Science; went to H.T. Kung of Carnegie-Mellon Univ., 1985.
• Responsible for Ph.D. recruiting in Computer Science at CMU, Illinois, Yale, Penn State, Penn.
• UNIX system administrator for departmental VAX-11/780, June 1984 - Dec. 1987.

External Funding

• NSF Grant MCS78-09126A01, joint with M.J. Irwin. VLSI Architectures and Algorithms for Recursive Computations. Award amount $123,820; July 1, 1980 - June 30, 1982.
• NSF Grant MCS-8202372. Parallel Computations (Computer Research). Award amount $65,550; July 1, 1982 - June 30, 1984.
• NSF Grant MCS-8203793, joint with M.J. Irwin and R.M. Owens. Computer Science and Computer Engineering Research Equipment. Award amount $55,653; June 15, 1982 - November 30, 1983.
• ONR Grant N0014-80-0517. Fundamental Research Initiatives, Digital Signal Processing. Award amount $22,432; July 1982 - October 1984. Principal Investigators: M.J. Irwin and R.M. Owens. Participating faculty: J.L. Barlow, D.E. Heller, J. Ja'Ja', J. Simon.
• ISU Center for Advanced Technology Development, Contract IPRT-CATD-00-34. HINT for Windows: Development and Testing Project.  Award amount $4,534 (Iowa Industrial Incentive Program) plus $4,534 (Technology Labs, Inc., Clear Lake, IA), May 2000 - June 2001.  Principal Investigator: L.L. Miller.  Project Director: D.E. Heller.

Explanatory note: I am a small-part-owner of Technology Labs, which licensed the HINT benchmark program from ISU for commercial development.  Relevant conflict-of-interest agreements are in place.  The company is now dormant.

Teaching Experience

• Pennsylvania State University, 1975 - 1983.  Undergraduate courses in numerical analysis, mathematical software, programming language concepts, information structures, computer architecture, and introductory programming. Graduate courses in numerical linear algebra, numerical solution of partial differential equations, and Runge-Kutta methods.
• Supervised three M.S. theses, two Ph.D. theses in Computer Science.
• So-Cheng Chen, Polynomial Scaling in the Conjugate Gradient Method and Related Topics in Matrix Scaling, October 1982.
• Ilse C.F. Ipsen, Stable Matrix Computations in VLSI, August 1983. Now with Dept. of Mathematics, North Carolina State University.
• Member of three Ph.D. committees in Computer Science and two in other fields (biophysics, industrial engineering).
• Departmental committees - Undergraduate Affairs, Undergraduate Honors Program, Graduate Affairs, Ph.D. Candidacy Exams, Recruiting and Personnel, Headship Search.
• Served as minority and veterans student advisor.
• Shell Development Co.  Initiated and taught an internal short course on parallel computing, with emphasis on programming tools and techniques for the nCUBE hypercube multiprocessor. Additional lectures on programming and debugging for the nCUBE.
• Iowa State University, adjunct position.
• Supervised three M.S. students in Computer Science.  Member of four M.S. committees in Computer Science and Computer Engineering, and one Ph.D. committee each in Mathematics, Computer Engineering, Computer Science.
• Undergraduate course, Introduction to Computer Architecture and Machine-Level Programming (CS 321).  Sophomore-junior level.
• Computer Science Undergraduate Committee member, 1999 - 2001.
• Pennsylvania State University, 2001 - present.
• Undergraduate course, Introduction to Computer Architecture (CSE 431).  Junior-senior level, Fall 2001.
• Undergraduate course, Operating Systems (CSE 411).  Senior level, Spring 2002, Fall 2002, Spring 2003, Fall 2003, Fall 2004, Spring 2005, Fall 2005.
• Undergraduate special-topics course, Dynamic Memory Allocation (CSE 497B).  Senior level, Spring 2004, Spring 2006.
• Undergraduate course, Introduction to System Programming (CSE 311).  Sophomore-Junior level, Spring 2006 (as CSE 497A).
• Graduate course, Numerical Linear Algebra (CSE 550).  Fall 2001.
• enrolled in PSU Course in College Teaching, July 2002.
• Engineering Advising Center, Spring 2003, Spring 2005.

Consultant Experience

• TRW Array Processors, Sunnyvale, Calif., 1980.
• National Science Foundation, Review Panel for New Investigator Research Grants in Experimental Computer Science, Feb. 1981.
• National Science Foundation, Review Panel for Computer Research Equipment proposals, Jan. 1985.
• U.S. Dept. of Energy, Nuclear Engineering Research Initiative, Review Panel for research proposals, Mar. 1999, Apr. 2000.

Professional Activities

• Programming and teaching experience in Algol 60, APL, C, C++, Fortran, Lisp, occam, PL/I, Pascal, perl, SNOBOL, Unix tools, Intel and MIPS assembler.
• Referee for research journals and technical conferences in numerical analysis and parallel computing.
• ACM Student Paper Competition, editorial committee member, 1972.
• Participant, High Performance Fortran Forum, 1992-4.
• Participant, Message Passing Interface Forum, 1993.
• Program Committee, Supercomputing '92.
• Gordon Bell Prize selection committee, 1993-4, session chair at Supercomputing '93 and '94.
• Tutorials Committee, Supercomputing '94.
• Participant, Dept. of Energy series of workshops on scalable cluster computing, 1996 - 1999.
• Participant, Parallel Tools Consortium, workshops and electronic forum on tool design and implementation, 1996 - 2001.

Additional Information

• Read Dutch, French, German, Romanian to varying degrees.
• Political party precinct chairman, 1987-90.
• Religious affiliation, several offices including financial secretary, treasurer and adult education coordinator, 1986-94, 1996 - 2001.
• Cub Scout den leader, 1989-90.
• Numerous publications and awards concerning Romanian philately.
• President, Mount Nittany Philatelic Society, State College, PA, 1980-82, 2002 - 2004.
• U.S. citizen.