Abstract: An improved squeeze bearing apparatus exhibits torsional stiffness or rotational restraint since its rod-like bearing member (22) and its sleeve-like bearing member (28) comprise non-circular perimeters (26,32).

Abstract: A signature verification system includes means for obtaining acceleration data and pressure data related to a given signature and means for comparing that data with reference data previously obtained from an identified signer. The correlations between segments of a reference pressure signal and a sample pressure signal are computed. This process involves successively measuring the correlation as the two segments are shifted with respect to each other. The amount of the shifts that produce the maximum correlations between the pressure signal segments is stored in memory, and these shift values are utilized to determine the correlations of respective pairs of segments of the acceleration data. Since the acceleration data is not independently shifted in computing the correlations, substantial processing time is saved. In addition, the overall performance of the signature verification system is improved both in terms of processing time and in error rate as compared to the prior system.

Abstract: A signature verification method is based on a comparison of the dynamics of a reference and a sample signature. Acceleration and pressure signals produced by a known person when writing his or her signature are stored and used as a reference signals. Then, at a later time, a person whose signature is to be verified writes his or her signature to produce acceleration and pressure signals that are compared to the reference signals. The process of comparison involves segmenting the two sets of signals to facilitate identifying regions of high probable correlation and then correlating corresponding segment pairs. Segmentation is based on pen lifts which represent reproducible timing marks in the signatures. According to the disclosed method, a pen or other writing instrument is used which produces a signal representative of the first time derivative of the pressure forces exerted on the stylus of the pen. The second time derivative of the pressure forces is computed from the measured signal.

Abstract: A signature verification system includes means for obtaining acceleration data and pressure data related to a given signature and means for comparing that data with reference data previously obtained from an identified signer. The correlations between segments of a reference pressure signal and a sample pressure signal are computed. This process involves successively measuring the correlation as the two segments are shifted with respect to each other. The amount of the shifts that produce the maximum correlations between the pressure signal segments is stored in memory. The corresponding segments of acceleration data are shifted with respect to one another by an amount which is .+-.1 time units of the stored shift values during subsequent correlations of the acceleration data.

Abstract: A writing implement having special applicability for use as a pressure and acceleration sensitive element for use in a Signature Verification System. The pen structure includes both a writing implement for making a visible record and also includes unique transducer structures for providing both acceleration and pressure data to a remotely located verification system. The pressure sensing element is axially mounted within the pen and produces pressure signals due to axial pressure on the pen tip as an individual writes. The accelerometer structure comprises a hollow tubular piezoelectric member supported at one end and having four circumferentially disposed electrodes on the outer surface thereof, which are appropriately interconnected to produce two orthogonal acceleration component signals A.sub.x and A.sub.y.