Statistical Signal Processing Applied in Communication Systems
Dr. Yuan has devoted much of his research resources to the field of statistical and adaptive signal processing and designed applications used in the communication systems at Fu Jen Catholic University since 1993. His major academic contributions are in the field of statistical signal processing and blind equalization, and he has published more than 10 academic papers in top-tier journals in the fields of signal processing and communications, such as IEEE Transactions on Signal Processing and IEEE Transactions on Communications. Dr. Yuan almost single-handedly developed computationally efficient and numerically stable smoothing (or two-sided filtering) algorithms as well as interpolation (or two-sided prediction) algorithms in lattice structures. These algorithms not only are generalizations of the extensively used one-sided filtering and one-sided prediction lattice algorithms but also have potential implications for communications, signal processing, and estimation problems. The algorithms are useful tools for channel equalization and estimation, data compression, coding and restoration of speech and images, and even narrowband interference suppression in spread spectrum communication systems. Some of his results have been extremely valuable and are therefore cited and briefly discussed in the most widely known textbook in the adaptive signal processing field, namely Adaptive Filter Theory by Simon Haykin (Englewood Cliffs, Pretence Hall, 1996, 3rd ed. and 2002, 4th ed.). Dr. Yuan was also invited to contribute to a book entitled QRD-RLS adaptive filtering—edited by José Antonio Apolinário Jr. (Springer, New York, USA; published February 2009)—in which he contributed to Chapter 5: QRD Least-Squares Lattice Algorithms. His summary of the QRD-LSL interpolation algorithms indicates not only how they generalize well-known QRD-LSL prediction algorithms but also how they can be employed to develop the widely known fast recursive least-squares algorithm.
More recently, Dr. Yuan’s research interests have shifted to blind (or unsupervised) equalization and the performance analysis of blind adaptive receivers by employing the multimodulus algorithm and the well-known constant modulus algorithm as well as the proposed blind carrier phase recovery algorithm for 8-VSB signals for the transmission of digital television in North America. Moreover, he has developed and analyzed adaptive blind decision feedback equalizers and adaptive blind decision feedback equalization on the basis of the prewhitening scheme and Newton method. Since the opening of Fu Jen Catholic University Hospital in October 2017, Dr. Yuan has begun to apply his knowledge of signal processing, machine learning, and optimization to medical applications—specifically cardiology—by working with well-known cardiologists.