Some neat animations of acoustic wave propagation are available at Time-Domain Simulations of Acoustic Propagation Through Shallow Water

Research Interests:

Please see the Bioinformatics and Computational Biology web site.

Algorithm Development, Bioinformatics, Machine Learning, Data Analysis, and Mathematical Modeling for Microbiology Applications.

For many years I pursued research on wave scattering from randomly rough surfaces which actually has many practical applications--from CGI to remote sensing to shallow water mine detection. However, I was doing very theoretical work, not applications, which involved trying to make judicious approximations to exact equations in order to make the resulting equations numerically tractable. There's a certain excitement to this work that's difficult to describe, but in the end, there's a lot of drudgery to it as well. There's more to it, but I suppose the bottom line is that I was just bored and needed a change. Most bored academicians probably don't make as radical a change as I did. Basically I went from being an applied physicist to becoming a virtual computer scientist working in the area of microbiology. However, this is the beauty of being in academia. There's nothing to stop you from changing your area of research. You have to do a lot of extra work, and you pay a real price in terms of giving up summer support until you're able to bring in research funding in your new area which is truly a challenge, but you're still getting paid and still productive. I don't know of any other job that allows such intellectual freedom.

Old and/or RSS Journal Publications:

• Broschat, S.L., L. Tsang, A. Ishimaru, and E.I. Thorsos, "A numerical comparison of the phase perturbation technique with the field perturbation and Kirchhoff approximations for random rough surface scattering," Journal of Electromagnetic Waves and Applications, Vol. 2, No. 1, 85-102, 1988. (large pdf)
• Broschat, S.L., C.K. Chou, K.H. Luk, A.W. Guy, and A. Ishimaru, "An insulated dipole applicator for intracavitary hyperthermia," IEEE Trans. Biomed. Engr., Vol. 35, No. 3, 173-178, 1988. (1.12Mb pdf)
• Broschat, S.L., E.I. Thorsos, and A. Ishimaru, "The phase perturbation technique vs an exact numerical method for random rough surface scattering," Journal of Electromagnetic Waves and Applications, Vol. 3, No. 3, 237-256, 1989. (large pdf)
• Broschat, S.L., E.I. Thorsos, and A. Ishimaru, "A heuristic algorithm for the bistatic radar cross section for random rough surface scattering," IEEE Trans. Geosci. Rem. Sens., Vol. 28, No. 2, 202-206, 1990. (916kb pdf)
• Manry, C.W., S.L. Broschat, C.K. Chou, and J.A. McDougall, "An eccentrically-coated dipole applicator for intracavitary hyperthermia treatment of cancer," IEEE Trans. Biomed. Engr., Vol. 39, No. 9, 935-942, Sep. 1992. (1.43Mb pdf)
• Yang, T.Q., and S.L. Broschat, "A comparison of scattering model results for two-dimensional randomly-rough surfaces," IEEE Trans. Antennas Propagat., Vol. 40, No. 12, 1505-1512, Dec. 1992. (1.23Mb pdf)
• Broschat, S.L., "The phase perturbation approximation for rough surface scattering from a Pierson-Moskowitz sea surface," IEEE Trans. Geosci. Rem. Sens., Vol. 31, No. 1, 278-283, Jan. 1993. (1.14Mb pdf)
• Broschat, S.L., J.B. Schneider, F.D. Hastings, and M.W. Steeds, "Interactive software for undergraduate electromagnetics," IEEE Trans. Educ., Vol. 36, No. 1, 123-126, Feb. 1993. (934kb pdf)
• Broschat, S.L., "The small slope approximation reflection coefficient for scattering from a `Pierson-Moskowitz' sea surface," IEEE Trans. Geosci. Rem. Sens., Vol. 31, No. 5, 1112-1114, Sep. 1993. (763kb pdf)
• Ivanova, K., and S.L. Broschat, "The method of the local parabolic approximation for rough surface scattering," J. Acoust. Soc. Am., Vol. 94, No. 4, 2326-2333, Oct. 1993. (1.11Mb pdf)
• Yang, T.Q., and S.L. Broschat, "Acoustic scattering from a fluid-elastic solid interface using the small slope approximation," J. Acoust. Soc. Am., Vol. 96, No. 3, 1796-1804, Sep. 1994. (1.16Mb pdf)
• Schneider, J.B., and S.L. Broschat, "The Measured Equation of Invariance method applied to randomly rough surfaces," Applied Computational Electromagnetics Society Journal, Vol. 10, No. 1, 19-30, Mar. 1995. (102kb gzipped ps)
• Thorsos, E.I., and S.L. Broschat, "An investigation of the small slope approximation for scattering from rough surfaces: Part I--Theory," J. Acoust. Soc. Am., Vol. 97, No. 4, 2082-2093, Apr. 1995. (1.72Mb pdf)
• Manry, C.W., S.L. Broschat, and J.B. Schneider, "Higher-order FDTD methods for large problems," Applied Computational Electromagnetics Society Journal, Vol. 10, No. 2, 17-29, Jul. 1995. (177kb gzipped ps)
• Hastings, F.D., J.B. Schneider, and S.L. Broschat, "A Monte-Carlo FDTD technique for rough surface scattering," IEEE Trans. Antennas Propagat., Vol. 43, No. 11, 1183-1191, Nov. 1995. (1.16Mb pdf)
• Manry, C.W., and S.L. Broschat, "FDTD simulations of ultrasound propagation in a 2-D breast model," Ultrasonic Imaging, Vol. 18, No. 1, 25-34, Jan. 1996. (2.32Mb pdf)
• Chen, Y., S.L. Broschat, and P.J. Flynn, "Phase insensitive homomorphic image processing for speckle reduction," Ultrasonic Imaging, Vol. 18, No. 2, 122-139, Apr. 1996. (806lb pdf)
• Steeds, M.W., S.L. Broschat, and J.B. Schneider, "A comparison of two conformal methods for FDTD modeling," IEEE Trans. Electromagnetic Compatibility, Vol. 38, No. 2, 181-187, May 1996. (1.54Mb pdf)
• Hastings, F.D., J.B. Schneider, and S.L. Broschat, "Application of the perfectly matched layer (PML) absorbing boundary condition to elastic wave propagation," J. Acoust. Soc. Am., Vol. 100, No. 5, 3061-3069, Nov. 1996. (412kb pdf)
• Broschat, S.L., and E.I. Thorsos, "An investigation of the small slope approximation for scattering from rough surfaces: Part II--Numerical studies," J. Acoust. Soc. Am., Vol. 101, No. 5, 2615-2625, May 1997. (414kb pdf)
• Hastings, F.D., J.B. Schneider, and S.L. Broschat, "A finite-difference time-domain solution to scattering from a rough pressure-release surface," J. Acoust. Soc. Am., Vol. 102, No. 6, 3394-3400, Dec. 1997. (285kb pdf)
• Schneider, J.B., C.L. Wagner, and S.L. Broschat, "Implementation of transparent sources embedded in acoustic finite-difference time-domain grids," J. Acoust. Soc. Am., Vol. 103, No. 1, 136-142, Jan. 1998. (1.78Mb pdf)
• Manry, C.W., and S.L. Broschat, "Inverse imaging of the breast with a material classification technique," J. Acoust. Soc. Am., Vol. 103, No. 3, 1538-1546, Mar. 1998. (9.48Mb pdf)
• Broschat, S.L., "Reflection loss from a `Pierson-Moskowitz' sea surface using the non-local small slope approximation," IEEE Trans. Geosci. Rem. Sens., Vol. 37, No. 1, 632-634, Jan. 1999. (210kb pdf)
• Liu, L.J., X. Zhang, and S.L. Broschat, "Ultrasound imaging using improved Iterative Born techniques," IEEE Trans. Ultrasonics, Ferroelectrics, and Freq. Control, Vol. 46, No. 3, 574-583, May 1999; Vol. 46, No. 5, 1331-1333, Sep. 1999. (1.04Mb pdf) (378kb pdf--erratum)
• Hastings, F.D., J.B. Schneider, S.L. Broschat, and E.I. Thorsos, "An FDTD method for analysis of scattering from rough fluid-fluid interfaces," IEEE J. Oceanic Eng., Vol. 26, No. 1, 94-101, Jan. 2001. (644kb pdf)
• Zhang, X., S.L. Broschat, P.J. Flynn, "A comparison of material classification techniques for ultrasound inverse imaging," J. Acoust. Soc. Am., Vol. 111, No. 1, 457-467, Jan. 2002. (648kb pdf)
• Zhang, X., S.L. Broschat, P.J. Flynn, "A conjugate gradient-neural network technique for ultrasound inverse imaging," J. Computational Acoustics, Vol. 10, No. 2, 243-264, Jun. 2002. (336kb pdf)
• Yang, T.Q., S.L. Broschat, and C. Galea, "A comparison of perturbation theory and the small slope approximation for acoustic scattering from a rough interface for a Biot medium," IEEE J. Oceanic Engineering, Vol. 27, No. 3, 403-412, Jul. 2002. (1.35Mb pdf)
• Yin, R., P.J. Flynn, and S.L. Broschat, "Position-dependent defocus processing for ultrasound holographic images," International J. Imaging Systems and Technology, Vol. 12, No. 3, 101-111, May 2002. (813kb pdf)
• Chen, Y., R. Yin, P.J. Flynn, and S.L. Broschat, "Aggressive region growing for speckle reduction in ultrasound images," Pattern Recognition Letters, online version published Jun. 2002, Vol. 24, No. 4-5, 677-691, Feb. 2003. (653kb pdf)
• Zhang, X., S.L. Broschat, and P.J. Flynn, "A numerical study of conjugate gradient directions for an ultrasound inverse problem," J. Computational Acoustics, Vol. 12, No. 4, 587-604, Dec. 2004. (382kb pdf)
• Broschat, S.L., F.J. Loge, J.D. Peppin, D. White, D.R. Call, and E. Kuhn, "Optical reflectance assay for the detection of biofilm formation," J. Biomedical Optics, Vol. 10, No. 4, 044027:1-6, Jul./Aug. 2005. (728kb pdf)
• Broschat, S.L., D.R. Call, E.A. Kuhn, and F.J. Loge, "Comparison of the reflectance and Crystal Violet assays for measurement of biofilm formation by Enterococcus," Biofilms, Vol. 2, No. 3, 177-181, Jul. 2005. (278kb pdf)
• Wan, Y., S.L. Broschat, and D.R. Call, "Validation of mixed-genome microarrays as a method for genetic discrimination," Applied and Environmental Microbiology, Vol. 73, No. 5, 1425-1432, Mar. 2007. (372kb pdf)
• Leach, M.D., S.L. Broschat, and D.R. Call, "A discrete, stochastic model and correction method for bacterial source tracking," Environmental Science & Technology, online: Dec. 2007, print: Vol. 42, No. 2, 524-529, Jan. 2008. (194kb pdf)
• Meng, D., S.L. Broschat and D.R. Call, "A Java-based tool for the design of classification microarrays," BMC Bioinformatics, Vol. 9, No. 328, Aug. 2008. (364kb pdf)
• Broschat, S.L., and Y. Wang, "A practical cross section for scattering from rough surfaces at very low grazing angles in both the forward and backward directions," Waves in Random and Complex Media, Vol. 19, No. 3, 430-454, Aug. 2009.
• Wang, Y., and S.L. Broschat, "A systematic study of the lowest-order small slope approximation for a Pierson-Moskowitz spectrum," IEEE Geosci. Remote Sens. Letters, Vol. 8, No. 1, 158-162, Jan. 2011.
• Wang, Y., and S.L. Broschat, "The SSA+ for scattering from dielectric surfaces at very low scattering angles," Waves in Random and Complex Media, Vol. 21, No. 1, 57-68, Feb. 2011.