July - September 1996, Volume 17, Number 3


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Research and Development Updates


Basic Research

   Investigation of Signal Characteristics Using the Continuous Wavelet Transform
   J. Sadowsky


Applied Research

   Development of Optical Filters Based on Photorefractive Materials
   P. R. Schuster, J. A. Miragliotta, M. E. Thomas, and D. M. Rust

   Astronomical Refraction
   M. E. Thomas and R. I. Joseph



   Shared Aperture Technology Development
   T. A. Axness, R. V. Coffman, B. A. Kopp, and K. W. O'Haver


Information Technology

   Collaborative Virtual Prototyping
   J. S. Lombardo, E. Mihalak, and S. R. Osborne


Systems Engineering

   The Emerging Joint System of Systems: A Systems Engineering Challenge and Opportunity for APL
   W. H. J. Manthorpe, Jr.


System Integration

   Integration of the Evolved Seasparrow Missile into Ships of the NATO Seasparrow Consortium Navies
   S. A. Hyer, J. J. Johnston, and C. L. Roe


Book Review

   A Comprehensive Look at Flame Research
   R. G. Gann


APL Awards

   Awards for Publications and Research and Development
   L. L. Maier-Tyler


In Memoriam

   Chih Kung Jen - A Remembrance
   W. G. Berl



   Publications, Presentations, and Colloquia

The cover: What are seemingly rock columns in a cavern are actually features of a time versus scale representation of a transient signal. The image was generated with a continuous wavelet transform using a Morlet wavelet (see the article by J. Sadowsky in this issue). The transform produces a complex image (i.e., each pixel has both intensity amplitude and phase). Phase is represented as saturation by black dots, and amplitude is represented as grayscale, where darker gray corresponds to higher amplitude. The horizontal direction in the image is time, and the vertical direction is scale; the smaller scale representing finer detail is at the top. The periodicity of the columns indicates frequency at the scale and is due to the phase of the complex image. (Cover illustration by Kenneth R. Moscati.)

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© 1996 by The Johns Hopkins University Applied Physics Laboratory

The Electronic Version of The Johns Hopkins APL Technical Digest was created by the Technical Publications Group (TIR).