Abstract: An iterative spline interpolation method for a numerically-controlled machine tool device is disclosed. The non-uniform rational B-spline (NURBS) curve inputted to the numerically-controlled machine tool is interpolated with a constant step size providing the ability to maintain a controlled velocity to within a specified tolerance. In addition, the distance left to travel on the curve is obtained by a unique spline node-based approximation method providing accurate acceleration and deceleration control. The rational spline interpolation method provides significant reduction in the amount of data required to produce smoothly machined pieces while providing accurate machining of conic sections not possible by previous spline interpolation methods.

Abstract: A method and system is provided for conducting secure power line carrier communications in full duplex over the power lines of a building. Power line carrier current telephone extension systems utilize 1) a single BASE unit per central office line (for interfacing line carrier signals with the central office line) and 2) one or more EXTENSION units, one for each extension phone set (for interfacing said line carrier signals with said extension phone sets).

Abstract: A system for power coupling independent of the position of the receiver over a surface. This is achieved by developing a spatially-dependent phase shift in the electromagnetic field generated by the power transmitter. The power inputs to the power receiver are then driven 180 degrees out of phase at any coordinate in the plane over the surface. An array of elements is placed in a plane below a surface and driven with a series of alternating current power sources. Consecutive adjacent elements across the area of the plane are driven with uniformly increasing phase shift. An integral multiple of adjacent consecutive elements results in a 180 degree phase shift. Pairs of field receiving elements in a power receiver are dimensioned to receive fields that are separated by 180 degrees of phase. Utilizing the technique of the invention, power coupling independent of the position or rotational orientation of the power receiver can be obtained.

Abstract: A Variable Frequency Drive Power Center incorporating a new passive Harmonic Filter in an improved housing structure for Variable Frequency Drives (VFDs). The new harmonic filter improves the overall system performance by drastically reducing the line side current harmonics generated by all VFDs. The harmonic filter includes a series inductance, a parallel capacitance, and a buck transformer. The filter provides a low impedance path for the harmonic currents generated by VFD and therefore prevents them from flowing into the input ac power lines. The filter also improves the input power factor of the VFD system because of its increased inductive reactance under full-load conditions. Although the filter causes an overvoltage across the VFD terminals because of its increased capacitive reactance at the fundamental frequency this problem is overcome by using the buck transformer.

Abstract: An improved method for error recovery in client-server distributed processing systems using cascaded servers. The method adds an additional form of acknowledgement message from a server to its predecessor. This message is sent when the server has completed all its processing and has received an ACK message from its successor, indicating that its result has been successfully received by the successor. The predecessor server retains a copy of its results until it receives the done message, at which time the copy of the results is discarded. If a done message is not received by the time a timer has expired, indicating that a problem has occurred with a server or its communications, the predecessor server resends its stored results.

Abstract: A method and system for synchronizing the presentation of data from different, but related, sources in different windows of a computer display. Data is positioned using duplicate sectional names that are in each of the data sources that are being synchronized. Even though the sectional names in each data source are the same, the contents of the sections can be different, independent, and unrelated. Multiple views of a single data source in different windows can be synchronized, showing data from many different locations within each data source. This allows authors and content experts to simultaneously show data from dissimilar data sources that have a logical connection, such as footnotes or commentary to a text, translations of a text, or updates to a read-only file.

Abstract: A method and system for conducting multiple access simultaneous telephone communications in full duplex either over the power lines of a building or using RF transmission. It employs a combination of multiple access techniques selected from among the following: time division, code division, and frequency division. The following features result: a) security coding to prevent unauthorized access and eavesdropping, b) multiple simultaneous conversations through identical and closely coupled transmission media, c) non-interference to other communications systems and users, and d) processing gain for operating in noisy environments.

Abstract: A stabilization assembly for securing and stabilizing two or more bicycles on a bicycle rack. In a presently preferred embodiment, the assembly comprises a stabilization bar which can be selectively varied in length by sliding one tube within another. Each end of the stabilization bar is provided with a cradle and a securing strap. The stabilization bar is attached to the frame of each bicycle by resting a portion of the frame within one of the cradles and wrapping the associated securing strap around the frame. The strap is then secured to the frame using hook and loop fastener surfaces or other suitable means.