International Business Machines Corporation

Thomas K Worthington

Timothy Joseph Chainer

David A Thompson

Robert A Scranton

William Joseph Gallagher

Steven C Gundersen

Subhash Laxman Shinde

Dwayne Thomas Crump

Timothy Rea Dinger

Jonathan James Hurd

Steven Taylor Pancoast

Arthur Davidson

Clifton D Cullum, Jr

Stephen Taylor Pancoast

Improved conductors and superconducting magnets are described utilizing superconducting materials exhibiting critical field anisotropy. This anisotropy is one in which the ability of the superconductor to stay in a superconducting state depends on the orientation of a magnetic field applied to the superconductor with respect to the direction of current flow in the superconductor. This anisotropy is utilized in the design of conductors and magnet windings comprising the superconductive material and specifically is directed to magnet windings in which the direction of high critical current through the superconductor is parallel to the magnetic field produced by current in these windings in order to obtain high critical fields. Particularly favorable examples of a superconducting material are the so-called high T superconductors in which the primary supercurrent flow is confined to 2 dimensional Cu&mdash;O planes. By arranging the superconductive windings so that the Cu&mdash;O planes are substantially parallel to the magnetic field produced by current in these windings, the windings will be able to withstand high fields without being driven normal. This maximizes the magnetic field amplitudes that can be produced by the magnet.

High current conductors and high field magnets using anisotropic superconductors

Disclosed is a method and apparatus for processing two analog composite video signals to be displayed to a human observer. The system includes at least a first and a second video source for generating first and second analog composite video signals respectively, and a selector coupled to the first and second video sources. The selector is operative to supply either the first or second analog composite video signal to one input of a video processor and independently and simultaneously supply either the first or second analog composite video signal to a second input of the video processor. The video processor is operative under control of a CPU to generate an output analog composite video signal comprised of a portion of the analog composite video signal supplied to the video processor's first input and a portion of the analog composite video signal supplied to the video processor's second input.

Method and system for processing two analog composite video signals

Disclosed are apparatus and method for measuring a characteristic of a film comprised of a material that is a superconductor below a critical temperature. The apparatus includes a magnetic circuit for inducing an alternating magnetic flux at a localized region of a surface of the film. The circuit includes a magnetic core (42) having a gap (44) made therein and a drive winding (46) coupled thereto. A current source (50) is coupled to the drive winding for passing an alternating current therethrough for inducing an alternating magnetic flux within the gap. Measurement circuitry (54, 56) is responsive to a current induced within the film by an entry of the magnetic flux into the film. A processor (60) is coupled to the measurement circuitry and determines a critical current density of the superconducting film within the localized region. The measurement circuitry includes a sense winding (48) that is coupled to the core and detects a magnitude of an electrical signal induced in the sense winding by the alternating magnetic flux.

Method and apparatus for determining at least one characteristic of a

A superconductive transmission line is formed of mixed metallic oxide ceramic material, particularly Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x drawn epitaxially upon a substrate. The superconductive material has basal crystallographic planes in alignment with copper oxide of the ceramic material. The planes are parallel to the substrate. The transmission line is constructed of a plurality of electrically conductive elements, each of which is formed of the superconductive material. The conductive elements are arranged with the crystalline planes parallel to an axis of the transmission line, along which axis power is to flow. Thereby, magnetic fields induced by currents flowing in the conductive elements intersect the conductive elements perpendicularly to the basal crystallographic planes to maximize the current which can flow while retaining linearity between magnetization and applied magnetic field. Thereby, alternating current can be transmitted by the transmission line without the introduction of hysteresis losses which would develop heat and quench the superconducting characteristic of the transmission line.

Oriented superconductors for AC power transmission

An improved signature verification method using dynamic signature characteristics in the frequency domain. Analysis of a signature in the frequency domain is employed when time domain analysis does not adequately distinguish between true signatures and forgeries. The preferred signature characteristics that are measured are two acceleration components of the pen, and the rate of change of axial pressure on the pen. More specifically, correlation functions operating on a sample and reference signature produce a correlation score. If the total correlation score is in a selected interval, then the above measured characteristics are analyzed in the frequency domain with the magnitude squared coherence function.

Signature verification algorithm

A linear disk actuator is disclosed incorporating a magnetic circuit for reducing stray magnetic fields in the region of the disks and recording heads of a magnetic recording disk system. The moving part of the actuator is provided with a plurality of coils mounted thereon, at least two of which are energized simultaneously and in magnetically opposing relationship to reduce the amplitude of the stray magnetic fields. Movement of the actuator is achieved by both energized coils interacting with a set of alternating poles positioned on the stationary part of the actuator.

Multiple coils for reduction of stray magnetic fields in disk file

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.

Shifting technique for signature verification

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. The first and second time derivatives are examined to detect quiet times indicative of lifting the pen from a writing surface. The detected quiet times are checked to determine if they have a time duration which exceeds a predetermined time period. The polarity and amplitude of the second time derivatives are tested to determine if they are positive and exceed a predetermined threshold at the beginning and end of each detected quiet time. Preferably, the steps of detecting quiet times, examining the duration of the quiet times, and testing the polarity and amplitude of the second derivatives are performed concurrently.

Segmentation algorithm for signature vertification

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. The overall performance of the signature verification system is improved both in terms of processing time and in error rate as compared to the independent shifting method and in error rate with a minor increase in computation time as compared to the pressure only shifting method.

Semi-independent shifting technique for signature verification

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.

Data input pen for Signature Verification

A linear motor adapted for driving a magnetic recording head reciprocably across the surface of a magnetic recording disk in a disk file has its stator located between the disks. The stator includes parallel magnetic yokes composed of plates extending parallel to the disks. At least one of the plates carries an array of regularly spaced and alternating magnetic pole elements, rigidly secured to one yoke with a gap extending between the yokes including the alternating poles providing a space within which the armature reciprocates, from one magnetic polarity to the opposite a plurality of times per reciprocation of the armature. End poles are provided at each end of the array, which are matched to collect the return flux from the adjacent distal pole to reduce fringing flux which emanates towards the disks and the recording heads.

Low mass actuator system for magnetic recording disks with half strength

A magnetoacoustic system adapted to use as a keyboard can employ a serpentine acoustic delay line passing under a number of transducers which are activated simultaneously with a current pulse through the wire. Magnets adjacent to the wire generate magnetoacoustic pulses along the wire which arrive sequentially at a sensor at one end of the line. For each key on a keyboard at least two magnets are associated with each key position with one magnet affixed in position and one reciprocably movable towards and away from the wire in a response to actuation of the key. The magnet which remains close to the wire is used to provide a 'location' signal indicating the location along the delay line provided by the wire by producing an acoustic pulse for that point on the wire for each clock pulse of current which passes through the wire. The second magnet located adjacent to the first magnet generates a pulse simultaneously with the other magnets when the current pulse passes through the wire, but it is delayed by the physical displacement along the wire, so it is received at a different time than the pulse from the other magnet. The data pulse can follow or precede the location pulse so long as the presence of one or both can be readily decoded. A three magnet key arrangement can be employed where it is desired to be able to use three positions per key.

Coding schemes for acoustic delay line data collection system

Using a sonic delay line approach, the distance of a point from the ends of a wire is measured by the time required for an acoustic pulse to move along a wire. A magnetostrictive wire extends between its endpoints with several magnetic pickup coils connected in series located at each end of the wire which are adapted to pick up an encoded train of magnetoacoustic signals. A position signalling electromagnetic drive head can be moved along the coil to any desired position. The head can be pulsed electrically to produce an appropriate sequence of acoustic pulses in the magnetostrictive wire. When those pulses are received by an appropriate sequence of coils connected in series which are properly connected (plus and minus), a large pulse is produced at one time position of the waves as they pass through the sequence of coils. Otherwise, a small signal is produced while the pulses pass by. The drive head comprises a Barker sequence coil which produces 3, 7, or 11 pulses in a Barker sequence, which gives a maximum positive autocorrelation, with an output of less than zero for all other positions of the sequence of pulses as they pass through a series of coils. This large output signal is used in conjunction with a timer to provide position measurement. By placing detectors at both ends of the wire, it is possible to provide self-calibration against thermal and other drifts in accuracy and to provide immediate warning of noisy or invalid readings.

Growing community of inventors

New York, NY, United States of America

Thomas K Worthington