Abstract: Speech recognition is improved by splitting each feneme string at a consistent point into a left portion and a right portion. The present invention addresses the problem of constructing fenemic baseforms which take into account variations in pronunciation of words from one utterance thereof to another. Specifically, the invention relates to a method of constructing a fenemic baseform for a word in a vocabulary of word segments including the steps of: (a) transforming multiple utterances of the word into respective strings of fenemes; (b) defining a set of fenemic Markov model phone machines; (c) determining the best single phone machine P.sub.1 for producing the multiple feneme strings; (d) determining the best two phone baseform of the form P.sub.1 P.sub.2 or P.sub.2 P.sub.

Abstract: In a speech recognition system, discrimination between similar-sounding uttered words is improved by weighting the probability vector data stored for the Markov model representing the reference word sequence of phones. The weighting vector is derived for each reference word by comparing similar sounding utterances using Viterbi alignment and multivariate analysis which maximizes the differences between correct and incorrect recognition multivariate distributions.

Abstract: Apparatus and method for modelling differential pulse code modulation (DPCM) input data for entropy coding. In particular, the sign and magnitude of one piece of DPCM data after another are modelled to provide a magnitude state input and a sign state input to provide context for DPCM magnitude input and DPCM sign input, respectively, to an entropy encoder or decoder. That is, the DPCM magnitudes of earlier pieces of (context) DPCM magnitude data are re-mapped for each such earlier piece of data, the re-mapped data being aggregated to form a combined value indicative of the magnitude state input. Similarly, the DPCM signs of earlier pieces of (context) DPCM sign data are re-mapped for each such earlier piece of data, the re-mapped data being aggregated to form a combined value indicative of the sign state input. In an image data compression system, the magnitude state input serves as an activity indicator for picture elements (pixels) neighboring a "subject" pixel.

Abstract: Speech words are recognized by first recognizing each spectral vector identified by a label (feneme), then identifying the word by matching the string of labels against phones using simplified phone machines based on label and transition probabilities and Merkov chains. In one embodiment, a detailed acoustic match word score is combined with an approximate acoustic match word score to provide a total word score for a subject word. In another embodiment, a polling word score is combined with an acoustic match word score to provide a total word score for a subject word. The acoustic models employed in the acoustic matching may correspond, alternatively, to phonetic elements or to fenemes. Fenemes represent labels generated by an acoustic processor in response to a spoken input. Apparatus and method for determining word scores according to approximate acoustic matching and for determining word scores according to a polling methodology are disclosed.

Abstract: In a distributed system whose state space is partitioned into recovery units, wherein recovery units communicate by the exchange of messages and wherein a message received by a recovery unit may causally depend on other recovery units having received prior messages, a method of recovering from failure of any number of recovery units in the system comprising the steps of: (a) tracking the dependency of each message received by a recovery unit in terms of the causative messages received by other recovery units in the system; and (b) restoring all recovery units to a consistent system-wide state after recovery unit failure by means of the tracked message dependencies.

Abstract: An effective wind/breath screen for a microphone is described. The wind/breath screen includes a rigid perforated structure for enclosing the microphone. The microphone being physically isolated from the rigid perforated structure by a surrounding pad of air therebetween. A porous layer is utilized to enclose the rigid perforated structure thereby creating a pad of dead air between the microphone and the porous layer, whereby the speech signal reaches the microphone without substantial attenuation, and the wind/breath noise is suppressed. The present wind screen for a microphone is optimized for, and is particularly effective for voice data entry applications.

Abstract: An implantable programmable medication infusion system comprises an implantable portion (2) having a medication reservoir (10) at below body pressure and isolated at its input from the body in which it is implanted by an antechamber (8) the pressure integrity of which is checked before filling the medication reservoir (10). Safety features include a leak detector (35), inlet and outlet valves (14 and 212) used with flow impeding filters (12 and 218), and a maximum allowable pressure in a pulsatile bellows pump (202) all of which prevent undesired infusion of medication. Medication flow from the pulsatile bellows pump (202) is in response to programming commands from a drug programming system (1) and processed in an electronics section (30) which uses the commands to program memory units (320 and 322) and to request pulses of medication. Hardwired limit controls (324 and 326) prevent excessive dosage requests from reaching the pulsatile bellows pump (202).

Abstract: A cylindrical wood-burning firebox is surrounded by a cylindrical metal outer shell which together comprise a convection heater stove which fits into any of various sizes of fireplaces with the cylinder axes directed into the fireplace. Room air enters the lower front portion of the stove between the firebox and the outer shell, is drawn toward the rear of the heater stove, rises between the firebox and the outer shell as the air is heated by the firebox, and exits as hot air from the upper front of the stove between the firebox and the outer shell. The front face of the firebox is recessed relative to the outer shell. A coil through which a fluid can flow can be provided in the gap between the firebox and the outer shell, said coil having an axis also directed into the fireplace.

Abstract: A generated signal is passed through an elongated signal conveying element positioned preferably perpendicular to the surface of a fluid the level of which is to be measured. The signal is directed from the signal conveying element to a detector element which senses the signal output from the signal conveying element. The signal output detected varies linearly with the depth of immersion of the signal conveying element into the fluid. In one embodiment, the signal conveying element is a capacitive probe comprising two plates or wires, one of which is grounded to the fluid into which the two plates or wires are immersed. Proper selection of accompanying circuitry results in detected signal changes which vary linearly with immersion changes. A second embodiment employs an electromagnetic wave, e.g. light, signal which passes through a light pipe signal conveying element. By nearly matching the light pipe index of refraction with that of the fluid, a predetermined percentage of the wave is lost into the fluid.

Abstract: The present invention relates to a method and apparatus for detecting the earth's static electric field and determining the contour of its equipotential lines and surfaces and for utilizing the detected field as a reference for other measurements. In particular, the contour of the field can be determined by sensing the potential at a plurality of points and measuring the differences in potential at the points with a differential static amplifier. Alternatively, a fluxmeter for measuring the electric field vector directly can be used to sense changes in the magnitude and direction of the field. A line defined between two points or a plane defined by three noncolinear points in space can be made to coincide with an equipotential line or surface in space, respectively, by adjusting the relative positions of the points such that either the potential differences between the points or the field components sensed along the defined line or in the defined plane are zero.

Abstract: Pulsed light and readily measurable pulsed electrical energy are independently applied to a solid black, conductive sample in a gas-filled photoacoustic cell, each causing the black sample to heat. The heating of the black sample causes a pressure wave in the cell, which can be detected and measured. By adjusting the pulsed electrical energy, the pressure wave resulting from the pulsed electrical energy can be made to relate to the pressure wave resulting from the pulsed light in a predetermined manner. The pulsed light input intensity can then be measured in electrical units based on the measurable input of the electrical energy pulses. In this manner, the invention can be used as a radiometer. A second application for the present apparatus is in calibrating photoacoustic spectroscopy (PAS) cells. The PAS cell can be self-calibrated by discontinuing the light pulses and relating the pressure wave output to the electrical energy pulse input.

Abstract: The present invention relates to a sensing device having a chamber containing positive and negative ions, wherein a fluid flow is directed into the chamber and ionized. The ionized flow passes between a plurality of conductive plates, the outputs from which can be used to indicate physical effects, such as air or gas flow and angular motion.

Abstract: The invention relates generally to measuring the air speed of an object moving within the earth's atmosphere. In particular, the invention provides apparatus which comprises means for causing an air flow to enter an electric E field chamber, proportional to air speed, a portion of the air in the air flow being ionized prior to entry into the E field. Air speed is measured by the current resulting from charge separation in the field.

Abstract: The present invention relates to an apparatus and method for detecting and correcting burst errors of indeterminate length occurring in data entered along a magnetic tape or other storage medium. An encoder and decoder arrangement is provided wherein parity or check bytes are encoded and decoded across data blocks which are measured along and across the tracks of the storage medium and wherein the parity or check bytes are read onto separate tracks of the storage medium. The present invention provides for the continuous encoding and decoding of data because the parity bytes and data bytes are conveyed to and from the storage medium along separate tracks.

Abstract: A method and apparatus for utilizing the earth's static electric field as a reference for generating an information-bearing electrical signal. In a particular embodiment, the invention provides a differential static voltmeter having spaced voltage sensing probes and a differential static amplifier which determines the difference in voltage sensed by the probes. Since the probes measure the static voltage which occurs as a vertically oriented gradient in the earth's atmosphere, the voltage difference signal produced by the differential static amplifier is a measure of the disposition of the probes relative to a line usually parallel to the earth's surface, the voltmeter thereby being particularly useful as a pitch and roll stabilization reference and control system for airborne vehicles. In other embodiments, the invention also provides apparatus for defining a horizontal reference plane in the atmosphere and apparatus for sensing the roll or pitch rate of an airborne vehicle.