Nancy Hubing

Statistical analysis of initialization methods for RLS adaptive filters

Theoretical analysis is used to evaluate the mean and second-moment properties of recursive least squares algorithms incorporating the fast exact initialization and soft constrained initialization methods during the initialization period. It is shown that the weight vector mean and covariance produced by fast exact initialization are undefined for this period. Theoretical results are derived for soft constrained initialization that show that the weight vector mean and covariance are finite, and expressions are given for these quantities. Simulations for various cases are presented to support the accuracy of these theoretical results. >

New perspectives for maximum likelihood time-delay estimation

This paper introduces a new realization for maximum likelihood time-delay estimation (TDE) that illuminates the relationships between maximum likelihood TDE and other methods. We obtain the result by deriving the likelihood function using a fundamental method that appears to be new to the field of array processing. This method is a natural complement to the generalized Karhunen-Loeve expansion.

Animated instructional media for stress transformations in a Mechanics of Materials course

Two unique instructional modules—the Plane Stress Transformations Module and the Mohrs Circle for Plane Stress Module—developed for the Mechanics of Materials course are presented. Formative assessment data gathered from Mechanics of Materials students pertaining to these courseware modules are presented and discussed. General conclusions and recommendations are presented.

Dynamic time warping comb filter for the enhancement of speech degraded by white Gaussian noise

An attempt is made to enhance speech degraded by added noise by exploiting the periodic nature of voiced speech. A modification of the adaptive comb filter is employed for this purpose. Problems which may arise when using the periodicity of the speech for enhancement include significant distortion caused by comb filtering a time-varying waveform (called temporal smearing) as well as the variation in pitch from period to period (called overload). It is shown that the dynamic time warping (DTW) comb filter corrects for variations in the vocal tract as well as the variation in pitch by using DTW. A computationally straightforward but suboptimal implementation of the time warping algorithm is used to improve the performance of the comb filter algorithm. Performance is based on computational complexity, informal listening tests, and segmental SNR.<<ETX>>

Exploiting recursive parameter trajectories in speech analysis

A novel approach to extracting voicing, pitch, and pitch pulse location information by processing the trajectories produced by weighted recursive least squares algorithms is presented. Traditional approaches to extracting this information usually involve performing an LPC analysis, calculating the residual using the LPC parameters, and then processing the residual using various methods. In this work it is shown that if an RLS algorithm is used for the LPC analysis, then extracting the pitch information from the parameter trajectories produced by the algorithm is an accurate alternative to residual-based pitch estimation. This approach also produces accurate LPC parameter estimates by selecting the RLS coefficients at the point just prior to the pitch pulse indicator.<<ETX>>

The Interdisciplinary Design Engineering Department: A Systems View, a Design Focus and Customizable Interdisciplinary Tracks

Graduates of traditional engineering programs are called on to fill a myriad of interdisciplinary design careers that are increasingly different than historical engineering jobs. These careers focus on complex problems and the importance of solving them quickly in order to be successful corporately and nationally, and demand the use of teams of interdisciplinary, people-and-process-intuitive professionals with special technical skills in engineering systems and engineering design. The students who will be needed to fill these jobs are different as well. They have grown up with computers, have seen that emerging technologies occur at the interface or outside the boundaries of traditional disciplines and are diverse in many ways beyond gender and ethnicity. National trends show smaller percentages of high school graduates are now choosing careers in engineering. In this paper we report on a fresh and innovative type of engineering department that will offer programs carefully designed to augment traditional departments and programs while providing the underpinning engineering design and systems skills to attract and create the engineers needed today. This new engineering department, called Interdisciplinary Design Engineering , will produce graduates who are experts in the process of designing engineering systems.Copyright

New perspectives for maximum-likelihood parameter and time delay estimation using two channels

This paper introduces a new realization for maximum likelihood parameter and time-delay estimation using two channels. We obtain the result by using coupled Karhunen-Loeve expansions to derive the likelihood function. The new realization illuminates the analytical relationship between maximum likelihood time-delay estimation and other methods. Experimental results that support the theoretical findings are included.

Maximum-likelihood time delay estimation: a new perspective

This paper introduces a new realization for maximum likelihood time-delay estimation. The new realization illuminates the relationships between maximum likelihood time delay estimation and other methods. We obtain the result by deriving the likelihood function using a fundamental method that, surprisingly, appears to be new to the field of array processing. This method is a natural complement to the Karhunen-Loeve transform having vector eigenfunctions and scalar eigenvalues, and it generalizes to M measurements, M/spl ges/2. Moreover, it can be applied to other multichannel estimation problems.

The WRLS algorithm for speech processing

Presents a theoretical analysis of the source of error of the weighted recursive least squares (WRLS) algorithm when it is used as a linear predictor. It has been generally accepted that the estimate from the WRLS algorithm has only two sources of error. When the WRLS algorithm is applied to a voiced speech signal, however, another source of error is found to exist. This error is termed the excitation error, since it occurs whenever the input signal has impulsive components. The properties of this excitation error are addressed. The effect of the impulsive components on the tracking ability of the WRLS algorithm is also analyzed, and it is shown that the existence of impulsive components actually enhances the tracking ability of the WRLS algorithm by reducing the initial magnitude of the lag error at epoch locations. This theoretical analysis has then been extended to the implementation of pitch determination algorithm and its verification.<<ETX>>