David Hamill

Biography

Dr David C. Hamill is currently conducting independent research into learning conversational systems.

He was recently retained as an expert witness by two major US computer corporations, advising on intellectual property matters including patent validity.

From 2001 he was the Chief Technical Officer of Maybot Ltd (now dormant), which he co-founded to develop natural language conversational systems and synthetic characters. He was also a Senior Visiting Fellow at the University of Surrey.

In October 2003, David organised the technical side of the 2003 Loebner Prize Contest, a Turing test for conversational systems.

Previously David was a Senior Lecturer at the University of Surrey, where he taught programming and electronics. He was affiliated to the Surrey Space Centre and conducted research in the areas of power electronics and nonlinear dynamics, with particular application to dc-dc converters.

Prior to joining the University in 1986, for seven years he was Technical Director of PAG Ltd, manufacturers of electronic equipment for the broadcast industry.

Before that, he ran Hamill Electronics Ltd, an electronics design consultancy covering embedded microprocessor systems, digital and analogue electronics. He started his career designing professional audio equipment, including magnetic recorders used in the film and broadcast industry.

David holds a bachelor's degree in electronic engineering and a master's degree in sound and vibration, both from the University of Southampton. He earned his PhD in power electronics from the University of Surrey. He is a Chartered Engineer, a member of the Institution of Electrical Engineers, a senior member of the Institute of Electronics and Electrical Engineers, and an affiliate member of the British Computer Society. In his spare time he plays the bass guitar, and enjoys composing and recording his own music.

Expertise

David Hamill's expertise covers:

• Natural language interfaces and conversational systems (chatterbots)
• Battery applications and battery charging and monitoring techniques
• Audio electronics and acoustics
• Musical instrument electronics and electronic music
• General analogue and digital electronics
• Power electronics, switched mode power supplies, dc-dc converters
• Nonlinear dynamics and chaos
• Web technology

In the IT area, he is familiar with the following technologies: HTML, Java, JavaScript, CSS, Flash, graphics, PHP, MySQL, Perl, Java, JavaScript, SQL, C, Pascal, Fortran, assemblers, Linux, Unix, SPICE, XML.

Publications

Below is a list of publications by David Hamill. Some of them are available to download as PDF files, and others will be made available as time allows. (If you are interested in a particular publication, please email us and we will do our best to produce a PDF for you.)

The publications are categorised as refereed journal papers, refereed conference papers, and other publications. Within each section the papers are in reverse chronological order.

Papers in Refereed Academic Journals

• [PDF] M. Tavakoli Bina and D.C. Hamill, "Average circuit model for angle-controlled STATCOM", IEE Proc. - Electric Power Applications, vol. 152, no. 3, pp. 653-659, May 2005
• [PDF] Y.H. Lim and D.C. Hamill, "Simple maximum power point tracker for photovoltaic arrays", Electronics Letters, vol. 36, no. 11, pp. 997-999, May 2000
• [PDF] L.V. Karadzinov and D.C. Hamill, "Analysis of the influence of diode reverse recovery on the operation and design of high-frequency rectifiers", IEEE Trans. on Power Electronics, vol. 15, no. 2, pp. 386-398, Mar. 2000
• [PDF] J.H.B. Deane, P. Ashwin, D.C. Hamill and D.J. Jefferies, "Calculation of spectral peaks in a chaotic dc-dc converter", IEEE Trans. on Circuits and Systems, Part 1, vol. 46, no. 11, pp.1313-1319, Nov. 1999
• PDF] Y.H. Lim and D.C. Hamill, "Chaos in a spacecraft power system", Electronics Letters, vol. 35, no. 6, pp. 510-511, Mar. 1999
• [PDF] P.J. Aston, J.H.B. Deane and D.C. Hamill, "Targeting in systems with discontinuities, with applications to power electronics", IEEE Trans. on Circuits and Systems, Part 1, vol. 44, no. 10, pp. 1034-1039, Oct. 1997
• [PDF] D.C. Hamill, "An efficient active ripple filter for use in dc-dc conversion", IEEE Trans. on Aerospace and Electronic Systems, vol. 32, no. 3, pp. 1077-1084, July 1996
• J.H.B. Deane and D.C. Hamill, "Improvement of power supply EMC by chaos", Electronics Letters, vol. 32, no. 12, p.1045, June 1996
• [PDF] D.C. Hamill, "Time reversal duality between linear networks", IEEE Trans. on Circuits and Systems, Part I, vol. 43, no. 1, pp. 63-65, Jan. 1996
• D.C. Hamill, "Half bridge class DE rectifier", Electronics Letters, vol. 31, no. 22, pp. 1885-1886, Oct. 1995
• [PDF] D.C. Hamill, "Impedance plane analysis of Class DE amplifier", Electronics Letters, vol. 30, no. 23, pp. 1905-1906, Nov. 1994
• D.C. Hamill, guest editorial, International Journal of Electronics, vol. 77, no. 5 (special issue on switched-mode dc power supplies), pp. 535-536, Nov. 1994
• D.C. Hamill, book reviews: B.E. Taylor, Power MOSFET Design; R. Bausière, F. Labrique and G. Séguier, Power Electronic Converters: DC-DC Conversion; R.E. Tarter, Solid-State Power Conversion Handbook; reviewed in: International Journal of Electronics, vol. 77, no. 5 (special issue on switched-mode dc power supplies), pp. 819-822, Nov. 1994
• [PDF] D.C. Hamill, "Lumped equivalent circuits of magnetic components: the gyrator-capacitor approach", IEEE Trans. on Power Electronics, vol. 8, no. 2, pp. 97-103, Apr. 1993
• D.C. Hamill, book reviews: W.W. Whittington, B.W. Flynn and D.E. Macpherson, Switched Mode Power Supplies: Design and Construction; A.S. Kislovski, R. Redl and N.O. Sokal, Dynamic Analysis Of Switching-Mode DC/DC Converters, reviewed in: International Journal of Electronics, vol. 74, no. 4, pp. 655-657, 1993
• [PDF] D.C. Hamill, "Learning about chaotic circuits with SPICE", IEEE Trans. on Education, special issue on computation and computers in electrical engineering education, vol. 36, no. 1, pp. 28-35, Feb. 1993
  [Zip archive of PSpice simulation files]
• [PDF] D.C. Hamill, J.H.B. Deane and D.J. Jefferies, "Modeling of chaotic dc-dc converters by iterated nonlinear mappings", IEEE Trans. on Power Electronics, vol. 7, no. 1, pp. 25-36, Jan. 1992
• [PDF] J.H.B. Deane and D.C. Hamill, "Chaotic behaviour in current-mode controlled dc-dc convertor", Electronics Letters, vol. 27, no. 13, pp. 1172-1173, June 1991
• D.C. Hamill, "On the LLC-type parallel resonant converter", IEEE Trans. on Aerospace and Electronic Systems, vol. 27, no. 3, pp. 564-566, May 1991
• [PDF] J.H.B. Deane and D.C. Hamill, "Instability, subharmonics and chaos in power electronic systems", IEEE Trans. on Power Electronics, vol. 5, no. 3, pp. 260-268, July 1990
• [PDF] D.C. Hamill and D.J. Jefferies, "Subharmonics and chaos in a controlled switched-mode power converter", IEEE Trans. on Circuits and Systems, vol. 35, no. 8, pp. 1059-1061, Aug. 1988
• D.C. Hamill, "Phase-locked induction heating inverter employing power MOSFETs", Electronics Letters, vol. 24, no. 7, pp. 439-440, Mar. 1988
• D.C. Hamill and B.R. Parker, "Advances in battery charging for portable video", SMPTE Journal, vol. 94, no. 3, pp. 296-304, Mar. 1985

Refereed Conference Papers

• [PDF] Y.H. Lim and D.C. Hamill, "Synthesis, simulation and experimental verification of a maximum power point tracker from nonlinear dynamics," Power Electronics Specialists Conf., Vancouver, Canada, vol. 1, pp. 199-204, June 2001
• [PDF] M. Tavakoli Bina and D.C. Hamill, "Transient response and stability of the Bootstrap Variable Inductance (BVI)", Power Electronics Specialists Conf., Vancouver, Canada, vol. 2, pp. 510-515, June 2001
• [PDF] L.V. Karadzinov and D.C. Hamill, "DH phenomenon in dc/dc converters", Power Electronics Specialists Conf., Vancouver, Canada, vol. 1, pp. 296-301, June 2001
• [PDF] M. Tavakoli Bina and D.C. Hamill, "Optimizing a discrete switching pattern using two simulated annealing algorithms", IEEE Workshop on Computers in Power Electronics, Blacksburg VA, pp. 129-133, July 2000
• [PDF] M. Tavakoli Bina and D.C. Hamill, "Average model of the bootstrap variable inductance (BVI)", Power Electronics Specialists Conf., Galway, Ireland, vol. 2 , pp. 967-972, June 2000
• [PDF] M. Tavakoli Bina and D.C. Hamill, "A classification scheme for FACTS controllers", European Power Electronics Conf., Lausanne, DS 3.6, Sep. 1999
• [PDF] M. Tavakoli Bina and D.C. Hamill, "Harmonic analysis of the PWM series/parallel Bootstrap Variable Inductance", Power Electronics and Drive Systems Conf., Hong Kong, vol. 1, pp. 22-27, July 1999
• [PDF] D.C. Hamill and P.T. Krein, "A 'zero' ripple technique applicable to any dc converter", Power Electronics Specialists Conf., Charleston SC, vol. 2, pp. 1165-1171, June 1999
• [PDF] M. Tavakoli Bina and D.C. Hamill, "The Bootstrap Variable Inductance: a new FACTS control element", Power Electronics Specialists Conf., Charleston SC, vol. 2, pp. 619-625, June 1999
• [PDF] Y.H. Lim and D.C. Hamill,"Problems of computing Lyapunov exponents in power electronics", International Symposium on Circuits and Systems, Orlando FL, vol. 5, pp. 297-301, May 1999
• [PDF] D.C. Hamill and M. Tavakoli Bina, "The Bootstrap Variable Inductance and its applications in ac power systems", Applied Power Electronics Conf., Dallas TX, vol. 2, pp. 896-902, Mar. 1999
• L.V Karadzinov and D.C. Hamill, "DH phenomenon in high frequency rectifiers", Power Electronics and Motion Control Conf., Prague, vol. 2, pp. 241-246, Sep. 1998
• [PDF] Y.H. Lim and D.C. Hamill, "Prospects for the application of nonlinear dynamics to spacecraft power systems", European Space Power Conf., Tarragona, vol. 1, pp. 265-270, Sep. 1998
• [PDF] Y.H. Lim and D.C. Hamill, "Bifurcations and chaos in models of spacecraft power systems", International Symposium on Nonlinear Theory and its Applications, Crans-Montana, Switzerland, vol. 1, pp. 335-338, Sep. 1998
• [PDF] Y.H. Lim and D.C. Hamill, "Nonlinear phenomena in a model space power system", IEEE Workshop on Computers in Power Electronics, Como, Italy, pp. 169-175, July 1998
• [PDF] N.O. Sokal, K.K. Sum and D.C. Hamill, "A capacitor-fed, voltage-step-down, single-phase, non-isolated rectifier", Applied Power Electronics Conf., Anaheim CA, vol. 1, pp. 208-215, Feb. 1998
• [PDF] L.V. Karadzinov and D.C. Hamill, "Influence of diode reverse recovery on the operation and design of high-frequency rectifiers", Applied Power Electronics Conf., Anaheim CA, vol. 1, pp. 447-453, Feb. 1998
• [PDF] D.C. Hamill, "Time reversal duality in dc-dc converters", Power Electronics Specialists Conf., vol. 1, pp. 789-795, St Louis MO, June 1997
• [PDF] D.C. Hamill, "Generalized small-signal dynamical modeling of multi-port dc-dc converters", Power Electronics Specialists Conf., vol. 1, pp. 421-427, St Louis MO, June 1997
• [PDF] D.C. Hamill, J.H.B. Deane and P.J. Aston, "Some applications of chaos in power converters", IEE Colloquium: Update on new power electronic techniques, ref. no. 1997/091, pp. 5/1-5/5, London, May 1997
• [PDF] D.C. Hamill, "Class DE inverters and rectifiers for dc-dc conversion", Power Electronics Specialists Conf., vol. 1, pp. 854-860, Baveno, Italy, June 1996
• [PDF] B. Baha and D.C. Hamill, "The design and modelling of resonant switched mode power supply (SMPS) using Simulink and Matlab", International Conf. on Software for Electrical Engineering Analysis and Design, pp. 35-44, San Miniato, Italy, May 1996
• [PDF] V.M. Van der Zel, M.J. Blewett, C. Clark and D.C. Hamill, "Three generations of dc power systems for experimental small satellites", Applied Power Electronics Conf., vol. 2, pp. 664-670, San Jose CA, Mar. 1996
• [PDF] D.C. Hamill, "Power electronics: a field rich in nonlinear dynamics", invited paper, Workshop on Nonlinear Dynamics of Electronic Systems, pp. 164-179, Dublin, July 1995
• D.C. Hamill and O.T. Toh, "Analysis and design of an active ripple filter for dc-dc applications", Applied Power Electronics Conf., vol. 1, pp. 267-273, Dallas TX, Mar. 1995
• K.N. Bateson and D.C. Hamill, "Cross regulation in two related multi-output resonant dc-dc converters", Power Electronics and Variable-Speed Drives Conf., pp. 262-267, London, Oct. 1994 (IEE conf. publication no. 399)
• [PDF] D.C. Hamill, "Gyrator-capacitor modeling: a better way of understanding magnetic components", Applied Power Electronics Conf., vol. 1, pp. 326-332, Orlando FL, Feb. 1994
• D.C. Hamill and T.P. Yeo, "Characterisation of cross regulation in dc-dc converters", International Telecommunications Energy Conf., vol. 1, pp. 372-378, Paris, Sep. 1993
• [PDF] D.C. Hamill and K.N. Bateson, "Design oriented analysis of a resonant ZVS/ZCS dc-dc converter", European Power Electronics Conf., vol. 3, pp. 23-29, Brighton, Sep. 1993 (IEE conf. publication no. 377)
• D.C. Hamill, "Chaos in switched-mode dc-dc converters", IEE colloquium on static power conversion, IEE digest no. 1992/203, pp. 5.1-5.4, London, Nov. 1992
• T.G. Foley and D.C. Hamill, "An efficient step-up/down dc preregulator for space applications", European Space Power Conf., pp. 99-105, Florence, Sep. 1991 (ESA SP-320, Aug. 1991)
• D.C. Hamill, "Problems of time-domain simulation in power electronics", UKSC Conf. on Computer Simulation, pp. 229-235, Brighton, Sep. 1990
• D.C. Hamill, "Time-domain simulation of resonant and other dc-dc converters", IEEE Workshop on Computers in Power Electronics, pp. 93-107, Lewisburg PA, Aug. 1990
• D.C. Hamill, "Time reversal duality and the synthesis of a Double Class E dc-dc converter", Power Electronics Specialists Conf., pp. 512-521, San Antonio TX, June 1990
• [PDF] J.H.B. Deane and D.C. Hamill, "Analysis, simulation and experimental study of chaos in the buck converter", Power Electronics Specialists Conf., pp. 491-498, San Antonio TX, June 1990
• J.H.B. Deane and D.C. Hamill, "Instability, subharmonics and chaos in power electronic systems", Power Electronics Specialists Conf., pp. 34-42, Milwaukee WI, June 1989
• D.C. Hamill, "Power MOSFETs in induction-heating cooking applications", 4th International Macroelectronics Conf., pp. 207-217, Munich, Nov. 1988
• D.C. Hamill and E.K.G. James, "Application of microprocessor technology to battery charging", 1st International Conf. on Power Sources and Supplies, pp. 3.2-3.2.8, London, Apr. 1987
• D.C. Hamill, "Microcomputer control enhances nicad battery fast charging", 39th NAB Broadcast Engineering Conf., pp. 241-249, Las Vegas, Apr. 1985

Other Publications, Reports, Presentations Etc.

• [PDF] D.C. Hamill and L. Hamill, "Purposes and structure of conversations", Colloq. on Conversational Systems, Guildford, Nov. 2005
• Technical organiser, Loebner Prize Contest, Univ. of Surrey, Oct. 2003
• [PDF] R. Balog, P.T. Krein and D.C. Hamill, "Coupled inductors - a basic filter building block", Electrical Manufacturing and Coil Winding Association Conf., Cinncinati OH, 2000; and Electrical Manufacturing and Coil Winding Association Letters, 2002
• D.C. Hamill, S. Banerjee and G.C. Verghese, Chapter 1: Introduction, pp. 1-24; and S. Banerjee and D.C. Hamill, Section 4.2: Techniques of numerical investigation, pp. 123-129; in: S. Banerjee and G.C. Verghese (editors), Nonlinear Phenomena in Power Electronics: Attractors, Bifurcations, Chaos, and Nonlinear Control: IEEE Press, Piscataway NJ, 2001, ISBN 0780353838
• P.T. Krein and D.C. Hamill, "Smoothing circuits", vol. 19, pp. 400-413, in: J.G. Webster (editor), Wiley Encyclopedia of Electrical and Electronics Engineering: Wiley, New York, 1999, ISBN 0471139467
• [PDF] N.O. Sokal, K.K. Sum and D.C. Hamill, "Step-down rectifier makes a simple dc power supply", EDN, pp. 169-180, 9 Apr. 1998
• D.C. Hamill, "European micro/minisatellites for affordable access to space", presentation at NASA Jet Propulsion Lab., Pasadena CA, Feb. 1998
• L. Hamill and D.C. Hamill, "Animation creation", NetUser, no. 14, pp. 32-38, Aug. 1996
• L. Hamill and D.C. Hamill, "The joy of JavaScript", NetUser: Part 1: no. 15, pp. 36-41, Sep./Oct. 1996; Part 2: no. 16, pp. 36-43, Nov. 1996; Part 3: no. 17, pp. 110-116, Dec. 1996
• Session co-chair, Power Electronics Specialists Conf., Baveno, Italy, June 1996
• Presentation on behalf of authors: P. Kocybic and K.N. Bateson, "Digital control of a ZVS full-bridge dc-dc converter", Applied Power Electronics Conf., Dallas TX, Mar. 1995
• Guest editor, International Journal of Electronics, vol. 77, no. 5 (special issue on switched-mode dc power supplies), Nov. 1994
• Session chair, IEEE Workshop on Computers in Power Electronics, Trois-Rivières, Québec, Aug. 1994
• D.C. Hamill, "Power-supply and battery considerations in rf design", IEE vacation school on rf circuit and system design, Guildford, July 1994
• Topic chair, modelling and analysis, Power Electronics Specialists Conf., June 1994
• D.C. Hamill and K.N. Bateson, "Advanced high-power dc-dc converters for space applications", final report, ref. 2064/113/XR(F), Defence Research Establishment, Farnborough, 1993
• Co-chair, Session 8: Modelling and simulation, Power Electronics Specialists Conf., Seattle, WA, June 1993
• K.N. Bateson, D.C. Hamill and B.E. Mulhall, "Development of a high-frequency dc-dc auxiliary converter", final report, ref. 8560/89/NL/JG, ESTEC, Noordwijk, Netherlands, 1993
• D.C. Hamill and K.N. Bateson, "Development of a high-frequency dc-dc auxiliary converter", final presentations, ESTEC, Noordwijk, Netherlands, Nov. 1992
• D.C. Hamill, "Power-supply and battery considerations in rf design", IEE vacation school on rf circuit and system design, Guildford, July 1992
• D.C. Hamill and J.H.B. Deane, "Power electronics, discontinuities and chaos", seminar, School of Mathematics, Univ. of Bristol, May 1992
• D.C. Hamill, "Tests on high-frequency electronic ballast for fluorescent lighting", report for Neilson Lighting Ltd., Industrial Electronics Group, Dept. of Electronic and Electrical Engineering, Univ. of Surrey, Nov. 1988
• D.C. Hamill, "Tests on high-frequency electronic ballast for fluorescent lighting", report for Neilson Lighting Ltd., Industrial Electronics Group, Dept. of Electronic and Electrical Engineering, Univ. of Surrey, Oct. 1988
• D.C. Hamill, "Evaluation of high-frequency electronic ballast for fluorescent lighting", report for Neilson Lighting Ltd., Industrial Electronics Group, Dept. of Electronic and Electrical Engineering, Univ. of Surrey, Mar. 1988
• D.C. Hamill and A.S. Way, "Using SPICE as a teaching aid", SPICE Users Group meeting, Chelmsford, Apr. 1987
• D.C. Hamill, "Outline design of a switched-mode power supply for an induction heated commercial cooking hob", report for Mealstream Ltd., Industrial Electronics Group, Dept. of Electronic and Electrical Engineering, Univ. of Surrey, Aug. 1986
• D.C. Hamill, "Fast charging nicad batteries under microcomputer control", Defence Communication and Security Review, no. 85/2, pp. 42-43, 1985
• [PDF] D.C. Hamill, "Transient response of audio filters", Wireless World, vol. 87, no. 1547, pp. 59-64, Aug. 1981
• D.C. Hamill and E.K.G. James, "Recent advances in the fast charging of sealed nickel-cadmium batteries", 122nd SMPTE Technical Conf., Paper 122-36, New York, Oct. 1980
• [PDF] D.C. Hamill, "Waa-waa unit for guitar effects", Practical Electronics, vol. 6, no. 7, pp. 568-570, July 1970