## Matt Yedlin's Current Research Interests and Publication RecordMy primary research interest focuses on aspects of acoustic wave propagation, including acoustic diffraction, asymptotic expansions, numerical wave modeling, laboratory wave modeling and most recently, source signature generation for seismic cross-well tomography. Publications (12), (13) and (15) focus on a novel method for the rapid, accurate computation of the acoustic edge-diffracted wave field. The emphasis shifts in publications (7), (9) and (18) to the comparison of acoustic diffraction theory with experimental data obtained using a linear swept-frequency source. The application of this source has facilitated the observation of creeping-wave diffractions (18) that compare very well with those synthesized using Fock functions. The foregoing analytical and experimental results have been complemented by (8), in which a uniform asymptotic method is presented for the solution of the two-dimensional inhomogeneous, source-driven acoustic wave equation. Only one functional representation is used, obviating the difficulty of the conventional asymptotic expansion which requires two functional representations. These analytical and experimental investigations have been supplemented by numerical modeling of the acoustic and elastic wave equations (publications 20 and 23 and a chapter in "Applications of High-Performance Computing in Engineering). These publications extend the spectral-time marching technique to include non-periodic and non-reflecting boundary conditions into the symbolic solution of the acoustic and elastic wave equations, yielding numerically synthesized wave field images that are less contaminated by numerical artifacts. My secondary area of research interest is applied digital signal processing. Publications (9), (11) and (13) demonstrate three different applications of digital signal processing to three different wave propagation problems. For example, in (9), a novel technique is developed for the separation of the reflected and edge-diffracted wave field, by application of the Karhunen-Loeve transform to experimentally generated acoustic scattering data. Publication(13) presents a new recursive filtering method for rapid, accurate generation of an acoustic, edge-diffracted wave field. The inherent problems of an integrable singularity and the long diffraction response tail are obviated in this new algorithm. The rapid and accurate calculation of edge diffractions are important in the numerical simulation of seismic data acquired over fault structures, such as those found in the North Sea. Most recently, these two research areas are merging, as I concentrate on the tomographic source signature problem, a collaborative project with Dr. E. L. Majer, Head, Subsurface Geophysics, Lawrence Berkeley National Laboratory (LBNL). This fusion is strongly representative of my joint appointment in the Departments of Geophysics and Astronomy and Electrical Engineering at the University of British Columbia and is an excellent example of cross-fertilization. My innovation has been the application of phase-modulated signals as a means of generating a source signature for the piezoelectric transmitter. In the summer of 1992, as a visiting scientist at LBNL, I developed the algorithm to generate these phase-modulated signals. My algorithm was inserted into the driving electronics for the piezoelectric transmitter and a test data set was collected in 1993. To facilitate the interpretation of this data set, in 1994, another field experiment was conducted in the San Francisco Bay. In July-August, 1995, an interpretation of the test data set was obtained, demonstrating the superiority of the phase-modulated signal over the conventional linear sweep. Coincident with the use of the phase-modulation method, a new solid-state power electronics system has been developed at LBNL. This system is ideally suited to the phase-modulation methodology I developed. It was taken into the field in July 1995 and two production environmental surveys were shot at Savannah River, North Carolina and Oyster, Virginia. Phase-modulation was used in both surveys. The Savannah River data was superior to that obtained previously using conventional linear frequency modulation. LBNL, under the auspices of the Department of Energy has supported my research contribution of phase-modulation source signature development in the past four years. A refereed conference paper entitled " Phase Modulation of Acoustic Transducers" was presented in 1993. A detailed publication on the 1993 test data set is 95% complete for journal submission. A patent application which incorporate the new hardware and my phase-modulation algorithm is being investigated. The phase-modulation seismic cross-well tomography project has resulted in two research extensions. Research on wide-band phased arrays has been disclosed and a marketing study has been completed. The disclosure is currently being evaluated by patent attorneys prior to filing a patent. Furthermore a confidentiality agreement has been agreed to in principal by UBC and AMOCO CANADA who have conducted a seismic acquisition test of the phased-array principles I have elucidated. The phase-modulation research and scattering research will be the focus of my sabbatical research plans and as such represent the continuation of the work described above. ## PUBLICATION RECORD
- Yedlin, M.J., H. Kwan, J.T. Murphy, H. Nguyen-Huu and Y.C. Wong, "Electrical Conductivity in Cat Cerebellar Cortex", Exp. Neurol., 43, 555--569 (1974). --- from M. Sc. Thesis in Neurophysiology.
- Yedlin, M.J. and B.R. Seymour, "The Turning Point of Elastic Waves in Transversely Isotropic Media", Geophys. J.R. Astr. Soc., 60, 301--306 (1980).
- Yedlin, M.J., "The Wavefront in a Homogeneous Anisotropic Medium", Bull. Seism. Soc. Am., 70, 2097--2101 (1980).
- Crampin, S. and M.J. Yedlin, "Shear-Wave Singularities of Wave Propagation in Anisotropic Media", J. Geophys., 49, 43--46 (1981).
- McMechan, G.A. and M.J. Yedlin, "Analysis of Dispersive Waves by Wavefield Transformation", Geophysics, 46, 869--874 (1981).
- Gonzalez, A. and M.J. Yedlin, "Ray Tracing Equations in Retarded Snell Co-ordinates", Geophysics, 49, 2100--2108 (1984).
- Narod, B.B. and M.J. Yedlin, "A Basic Acoustic Experiment for Demonstrating the Geometrical Theory of Diffraction", Am. J. Phys., 54, 1121--1126 (1986).
- Yedlin, M.J. "Uniform Asymptotic Solution for the Green's Function for the Two-Dimensional Acoustic Equation", J. Acoust. Soc. Amer., 81, 238--243 (1987).
- Yedlin, M.J., I.F. Jones, and B.B. Narod, "Application of the Karhunen-Loeve Transform to Diffraction Separation", I.E.E.E. Trans. Acoustics Speech and Signal Processing, 35, 2--8 (1987).
- Yedlin, M.J., B.R. Seymour and B.C. Zelt, "Truncated Asymptotic Representation of Waves in a One-Dimensional Elastic Medium", Geophysics, 52, 755--764 (1987).
- Zelt, C.A., J.D. Drew, M.J. Yedlin and R.M. Ellis, "Picking of Noisy Refraction Data Using Semblance Supplemented by Monte Carlo Statistics and Spectral Balancing", Bull. Seism. Soc. Am., 77, 942--957 (1987).
- Dalton, D.R. and M.J. Yedlin, "Exact Time-Domain Solutions for Acoustic Diffraction by a Half Plane", Surveys in Geophysics, 10, 305--330 (1989).
- Dalton, D.R. and M.J. Yedlin, "ARMA Implementation Of Diffraction Operators with Inverse-Root Singularities", I.E.E.E. Trans. Antennas Propagat., 38, 831--837 (1990).
- Yedlin, M.J., B.R. Seymour and B.C. Zelt, "Comparison of the WKBJ and Truncated Asymptotic Methods for an Acoustic Medium", Geophys. J. Int., 101, 49--60 (1990).
- Zhang, Q. E.V. Jull and M.J. Yedlin, "Acoustic Pulse Diffraction by Step Discontinuities on a Plane", Geophysics, 55, 749--756 (1990).
- Zhou, H., D.L. Pulfrey and M.J. Yedlin, "A Phenomenological Approach to Estimating Transit Times in GaAs HBTs", I.E.E.E. Trans. Elec. Dev., 37, 2113--2120 (1990).
- Zhao, S.K. and M.J. Yedlin, "Chebyshev Expansions for the Solution of the Forward Gravity Problem", Geophys. Prosp., 39, 783--802 (1991).
- Zhang, Q., E.V. Jull, G.R. Mellema and M.J. Yedlin, "Pulse Diffraction by a Curved Half-Plane", Wave Motion, 55, 173--184 (1993).
- Zhao, S.K. and M.J. Yedlin, "A New Iterative Chebyshev Spectral Method for Solving Elliptic Equations", J. Comput. Phys., 113, 215--223 (1994).
- Luo, Y. and M.J. Yedlin, "Polynomial Time-Marching for Non-periodic Boundary Value Problems", J. Sci. Comput., 9, 123--136 (1994).
- Nasiopoulos, P., Yedlin, M.J. and R. K. Ward, "A Fixed-Length Compression Method using the Karhunen-Loeve Transform", I.E.E.E. Trans. Consum. Electron., 41, 1189--1196, Nov. 1995.
- Luo, Y. and M.J. Yedlin, "Polynomial Time-marching for Non-reflecting Boundary Problems", accepted by the editor, J. Sci. Comput., 18 ms pages, Dec. 1995.
- Yedlin, M.J. and Y. Luo, "Incorporation of Absorbing Boundary Conditions into Acoustic and Elastic Wave Propagation Problems Solved by Spectral Time-Marching", in press, Advances in Engineering Software, 16ms pages, 4 figures, January, 1996.
- Zhao, S. and M.J. Yedlin, "Multi-domain Chebyshev Spectral Method for 3--D DC Resistivity Modelling", accepted by the editor,Geophysics, 13ms pages, 6 figures, Feb.,1996.
- Zhao, S. and M.J. Yedlin, "Some Refinements of the Finite Difference Method for 3--D Resistivity Modelling", Geophysics, 11 ms pages, 5 figures, in press, July, 1996.
## Refereed Conference ProceedingsYedlin, M.J. and D. Dalton, "Diffraction Coefficient Formulation of an Exact Solution for Acoustic Diffraction by a Half-Plane", Continuum Mechanics and its Applications, ed. Graham and Malik, 99--107 (1989). Luo, Y. and M.J. Yedlin, "Solving the Wave Equation by Pseudospectral Time-Marching on the CM-2 Connection Machine", Proceedings of Supercomputing Symposium '93, 387--394 (1993), Calgary, AB. Luo, Y., I.G. Cumming and M.J. Yedlin, "Benchmarking a Massively Parallel Computer by a Synthetic Aperture Radar Processing Algorithm, Applications of Supercomputers in Engineering III", edited by: C.A. Brebbia and H. Power, Computational Mechanics Publications, 393--408 (1993), Southampton, U.K. Luo, Y. and M.J. Yedlin, Simulating Some Complex Wave Scattering Problems on CM-2 Connection Machine by Pseudospectral Time-Marching, Applications of Supercomputers in Engineering III", edited by: C.A. Brebbia and H. Power, Computational Mechanics Publications, 547--560 (1993), Southampton, U.K. Yedlin, M.J. and E.L. Majer, "Phase Modulation of Acoustic Transducers", 270--273(1993), Canadian Conference on Electrical and Computer Engineering, Vancouver, B.C. Zhao, S. and M.J. Yedlin, "Chebyshev Domain Decomposition Methods for 3--D DC Resistivity Modelling", 389--391 (1993),63rd SEG Annual Meeting, Washington, DC. Luo, Y. and M.J. Yedlin, "Simulating Some 2--D Seismic Reflection Models on Fujitsu VPX 240 by Polynomial Time-Marching, Proceedings of Supercomputing Symposium '94, 86--93 (1994), Toronto, ON. Nasiopoulos, P., M.J. Yedlin and R.K. Ward, "A Fixed-Length Compression Method Using the Karhunen-Loeve Transform", 581--584 (1995), I.E.E.E. Pacific Rim Conference, Victoria, BC. Yedlin, M.J. and Y. Luo, "Incorporation of Absorbing Boundary Conditions into Acoustic and Elastic Wave Propagation Problems Solved by Spectral Time-marching", 297--304 (1995), Applications of High-Performance Computing in Engineering IV", edited by: H. Power, Computational Mechanics Publications, Southampton, U.K. Other --- Published Abstracts Yedlin, M.J., Narod, B. B., Mellema, G., Jull, E.V. and Z Qin, "The Imaging of Acoustic Scattering Data of Complicated Geological Structures", EOS Trans. A.G.U. , 71, pp. 1446 (1990). Yedlin, M.J., "Low Frequency Acoustic Scattering from Surface Irregularities", EOS Trans. A.G.U. , 72, pp. 305 (1991). Mellema, G., Yedlin, M.J.,and E.V.Jull, "High and Low Acoustic Scattering from Circular Cylinders", EOS Trans. A.G.U. , 72, pp. 305 (1991). Yedlin, M.J. and E.L. Majer, "Comparison of Phase-encoded and Swept-frequency Sources in Acoustic Tomography", EOS Trans. A.G.U. , 73, pp. 350 (1992). Yedlin, M.J., Majer, E.L., Peterson, J. and T. Daley, "Comparison of Cross-well Data Obtained Using Pulsed, Frequency-modulated and Phase-modulated Sources", EOS Trans. A.G.U. , 74, pp. 409 (1993). ## CHAPTERS IN BOOKSLuo, Y. and M.J. Yedlin, "Polynomial Time-marching and its Implementation on Supercomputers, Chapter 5 of Applications of High-performance Computing in Engineering", edited by H. Power, Computational Mechanics Publications, 189--222, (1995), Southampton, U.K. ## PATENTSSUBJECT: Phase of the rectified trace parameter as an aid to seismic interpretation (with B. Stebens, R. Parsons, D. Terral, and R.T. Baumel).. 6 patents granted (1986,1987) to Conoco Inc. in: Australia, Belgium-France-Netherlands, Canada, West Germany, Great Britain, U.S.A. |