Abstract: A method for beamforming digitized signals from a sensor array to enhance signals originating from a preselected angle of interest and a preselected range bin while suppressing interference signals from other angles of arrival. Snapshots of sensor data are acquired and used to estimate an autocorrelation function. An autoregressive model of power is determined over angles of arrival as polynomial coefficients and roots are calculated as associated with the interference signals. Roots are selected for suppression by providing nulls. Exponentials are constructed from the roots. The exponentials are used with variances from the autoregressive model to provide a synthetic covariance matrix having weights that suppress the interference signals.

Abstract: A method is disclosed for detecting unfair ratings in rating data over a period of time in connection with an on-line rating system. The method includes the steps of: detecting changes in an arrival rate of ratings in the rating data over the period of time and providing arrival rate change data; detecting changes in a model of the rating data over the period of time such that changes in the model are represented as model errors and providing model error data; detecting changes in a histogram of the rating data over the period of time and providing histogram detection data; detecting changes in a mean of the rating data over the period of time and providing mean change detection data; and processing the arrival rate change data, the model error data, the histogram detection data, and the mean change detection data to identify unfair ratings in the rating data.

Abstract: A zero crossing based spectrum analyzer, a method that samples zero crossings of a signal waveform containing only real zeros and uses this information to determine the discrete Fourier Transform coefficients, is disclosed. A band-limited signal represented by real and complex zeros is converted by invertible techniques to a signal that contains only real (physical) zeros. This converted signal is applied as the input signal to the zero crossing based spectrum analyzer.