Current areas of specialization include research, development, analysis and understanding of digital signal processing algorithms. Ongoing research efforts are directed toward improving understanding and performance of algorithms used in speech recognition, pattern detection and recognition, noise removal and enhancement of speech and image data using human hearing and visual models.
Responsible for as many as thirteen separate projects at the same time with budgets ranging in value from $2,500 to $400,000.
Development Department Manager: Manager of the Development Department at EG&G concurrent with the above described program responsibilities.
Demonstrated ability to assume responsibility for several different, concurrent projects (or one large one), organize the efforts to be accomplished, and assign and motivate the resources to accomplish the tasks in minimum time and for minimum cost. In this role, overall guidance of the technical aspects of the projects was provided to assure that high quality work was accomplished within the budget and schedule, and that the customer's actual needs were satisfied. Because of cross-disciplined education in Electrical Engineering and Physics, able to take diverse technologies and apply them to the problem at hand. Demonstrated an ability to relate to both the physics and engineering points of view.
September 1, 1978 to Present --Professor since 1984, Graduate Coordinator for 10 years through 1989, Electrical Engineering Department, Brigham Young University, responsible for graduate curriculum and supervising the graduate program, teaching undergraduate and graduate level courses, developing and directing research programs and supervising graduate student research work in Digital Signal Processing and Communication Theory. Have advised over 100 Masters Degree and 12 PhD Degree recipients in Electrical Engineering at Brigham Young University. While at BYU have been a Principal Investigator for over 2.5 million dollars of funded research.
March 1978 to August 31, 1978 -- Chief Scientist, Eyring Research Institute.
October 1, 1976 to March 1978 -- Director of the Applied Sciences Division of the Eyring Research Institute. Responsible for the technical and administrative management of all projects in the division. Some of these projects include low frequency antenna studies, High Energy Plasma Phenomena Study, Hyperspace/Predictive Techniques Research, Radiation Hardened Semiconductor Development Project, etc.
September 1974 to October 1976 -- Research Associate Staff member, Electrical Engineering Department, University of Utah. Responsible for conducting a two-year research effort in automatic word recognition in continuous speech using digital computer analysis. Techniques used included communication theory principles, nearest neighbor pattern matching, nonlinear time warping, linear prediction analysis of speech, Wiener filtering to extract speech signal from speech plus noise, and spectral analysis using Fast Fourier Transform and Linear Predictive Coded smoothed frequency spectrum. During this time, also worked on a contract with Hill Air Force Base as a consultant to propose changes and provide evaluations of the program to maintain the Electromagnetic Pulse hardness of the Minuteman Weapon System. This effort used the experience gained previously at EG & G. Supervised an experiment to produce laser x-rays using a high energy neodymium glass laser.
September 1, 1972 to September 1974 -- Software Sciences Corporation, Manager, Salt Lake City Operations. Responsible for all technical and administrative activities at the Salt Lake City operations. Program Manager on all major technical programs at Salt Lake City, including hardware and software.
January 1, 1969 to September 1, 1972 -- Employed by EG&G, Albuquerque Division, as Scientific Specialist. During this time, had the following responsibilities:
Digital signal processing, communication theory, information theory, neural network models applied to pattern recognition and analysis.
Ongoing research has been directed toward:
A digital model for the human hearing system, representing the transfer function between incoming acoustic pressure and electrical output to the auditory nerve. This research focuses on intelligibility issues for the normal and hearing-impaired individual and also the application of adaptive noise suppression
Image data compression applied to synthetic array radar, infrared images, television data and ordinary photographic images. This research focused on methods for recognizing targets in images and in aligning features in images
A computational technique that exploits a compression of "lossy" data to reduce computations required for any system with linear processing.
Author or Co-author of over 40 technical publications some of which are listed below.
D. M. Chabries, D. Anderson, T. G. Stockham Jr., and R. W. Christiansen, "Application of a Human Auditory Model to Loudness Perception and Hearing Compensation," IEEE/ICASSP May 1995.
Richard Frost, Chris Barnes, D. M. Chabries, and R. W. Christiansen, "System and Method For Data Compression Using Multiple Codewords and Transmitted Indices," US Patent 5,250,949, 1993.
D. M. Chabries, R. H. Brery, M. S. Robinette, R. W. Christiansen, and G. R. Kenworthy, "Digital Hearing Enhancement Apparatus," US Patent 5,029,217. July 2, 1991.
J. M. Scanlan, D. M. Chabries and R. W. Christiansen, "A Shadow Detection and Removal Algorithm for 2-D Images", Proceedings of IEEE ICASSP, April 1990, Vol 4, pp. 2057-2060.
T. J. Patterson, D.M. Chabries, R. W. Christiansen, "Detection Algorithms for Image Sequence Analysis," IEEE Transactions on Acoustics, Speech, and Signal Processing, Sept. 1989, Vol. 37, No. 9, 1454-1458.
Chabries, D. M., R. W. Christiansen, R. Brey, M. Robinette, and R. Harris, "Application of Adaptive Digital Signal Processing to Speech Enhancement for the Hearing Impaired," Journal of Rehabilitation Research and Development, submitted for publication October, l986.
Christiansen, R.W., D.M. Chabries, and D.B. Anderson, "Noise Reduction in Speech Using a Modified LMS Adaptive Predictive Filter," Proceedings IEEE/EM BS. Chicago, Ill., September 1985.
D. M. Chabries, R. W. Christiansen, R. Brey, M. Robinette, "Application of the LMS Adaptive Filter to Improve Speech Communication in the Presence ofNoise", Proceedings of ICASSP, IEEE, May 1982.
Christiansen, R.W., D. M. Chabries, and D. Lynn, "Noise Reduction in Speech Using Adaptive Filtering in Signal Processing Algorithms," 103rd ASA Conference, Chicago, Il., April 26, 1982.
R. W. Christiansen and D. M. Chabries, "Randomization and Masking Study for MX PLU", BYU Technical Report, Eyring Research Institute contract, Nov. 1980 (work performed for U.S. Air Force).
R. W. Christiansen and C. K. Rushforth, "Detecting and Locating Key Words in Continuous Speech Using Linear Predictive coding," published as a section in a chapter on Word Spotting in Automatic Speech and Speaker Recognition, Ed., N. Rex Dixon and T. R. Martin, IEEE Press, 1979.
R. W. Christiansen and C. K. Rushforth, "Detecting and Locating Key Words in Continuous Speech Using Linear Predictive Coding," IEEE Transactions ASSP, Vol, ASP-25, No. 5, October 1977.
R. W. Christiansen and C.K. Rushforth, "Word Spotting in Continuous Speech Using Linear Predictive Coding," Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, Philadelphia, Pennsylvania, April l2-l4, l976.
R. W. Christiansen, Word Recognition in Continuous Speech Using Linear Prediction Analysis, Ph.D. Dissertation, University of Utah, Salt Lake City, Utah, 1976. (Also issued as a technical report No. UTEC-CSc-76-226 by the Advanced Research Projects Agency of the Department of Defense.)