Abstract: Index terms are drawn from text documents without the need for language-specific processes or training and are suitable as gists for the subject documents. Index terms are extracted on the basis of scores of constituent n-grams relative to n-gram counts in a corpus. A method of extracting joint index terms to represent a plurality of documents is also provided.

Abstract: The present invention discloses a device for and method of correcting an error in a formatted modem transmission by receiving a formatted modem transmission into a receiving modem, identifying the formatting scheme of the transmission, testing the transmission to determine if a formatting error is contained therein, generating error patterns and associated correction patterns for the receiving modem based upon the format of the transmission and the type of descrambler used in the receiving modem, searching the transmission to determine if any of the generated error patterns is found therein, and replacing any error pattern found in the transmission with its associated correction pattern.

Abstract: A system for communicating simultaneous encrypted messages in a jamming eronment with a low opportunity for depth exploitation. The system includes a plurality of transmitters, each having a high speed key generator for producing a plurality of pseudorandom bit streams. The bit streams are combined with a unique identifier in each transmitter to produce a single unique key stream, which may be added to a binary data stream to create an encrypted message for transmission. The receiver includes a single key generator identical to those in the transmitters and a plurality of combiners and correlators to enable simultaneous recovery of each transmitted encrypted message.

Abstract: A laser-programmable clocked-logic integrated-circuit cell having a transmission gate; a first laser-cut area; a first two-input nand gate; a second two-input nand gate; a third two-input nand gate; a first inverter; a first tri-state clocked-inverter; a second laser-cut area; a second inverter; a third inverter; a second tri-state clocked-inverter; a third laser-cut area; a fourth two-input nand gate; a fifth two-input nand gate; a sixth two-input nand gate; a fourth inverter; a third tri-state clocked-inverter; a fourth tri-state clocked-inverter; a first laser-link area; a second laser-link area; a fourth laser-cut area; a fifth laser-cut area; and a third laser-link area.

Abstract: A computer process of creating a Moving Electron Beam Exposure System (MEBES) pattern-generation file, that is to be used in the manufacture of integrated-circuit masks, from a technology-independent and semiconductor-process independent layout-design, by transmitting a scaleable and process-independent layout design to a computer, selecting the layers necessary for a particular semiconductor-process, selecting the scale to which the layout design will be converted, converting the layout design to that scale, positioning the layout design in a full-wafer or reticle-based layout, adding scribe lines, converting the layout design to a format acceptable to a conversion program, converting the layout design to a MEBES pattern-generation file, and transmitting the MEBES pattern-generation file in a format acceptable to a manufacturer of integrated-circuit masks.

Abstract: A secure communication apparatus incorporates a longterm, non-extractable master key variable which is held in common by all terminals. A pseudorandom bit sequence generator within the transmitter provides a binary bit stream which is transmitted unencrypted to the intended receiver. Both terminals simultaneously mix the master variable with the transmitted pseudorandom bit stream in an identical manner to create a common separate working variable which is subsequently used for data encryption and decryption.

Abstract: A method of identifying, retrieving, or sorting documents by language or topic involving the steps of creating an n-gram array for each document in a database, parsing an unidentified document or query into n-grams, assigning a weight to each n-gram, removing the commonality from the n-grams, comparing each unidentified document or query to each database document, scoring the unidentified document or query against each database document for similarity, and based on the similarity score, identifying retrieving, or sorting the document or query with-respect to language or topic.

Abstract: An authenticator circuit and message authentication apparatus. The circuit includes a plurality of shift register stages, some of which are separated by adders having an input from a succeeding stage. Switching circuits selectively control the second adder inputs to determine the shifting sequence of information passing through the register stages. A message authentication apparatus includes a key generator and authenticator circuit converted at the output of a transmitter. The input of a receiver includes a similar authenticator circuit and key generator, plus a counter.

Abstract: The present invention relates to a device for and a method of performing an n-bit modular multiplication of A.times.B modulo C in approximately n/2 steps, where A denotes a binary multiplier, B denotes a binary multiplicand, and C denotes a binary modulus. A, B, and -C are stored in registers. All variables needed to perform the A.times.B modulo C are generated. A partial product register is initialized. The multiplier A is scanned two bits at a time. The value of these two bits determines the multiple of B added to the partial product register. The values 4C, 2C, and C are subtracted from the partial product. If any of these subtractions result in a negative number the result of that subtraction is discarded. The partial product is then shifted two significant positions and stored in the partial product register. These steps are repeated until every bit of A has been scanned. The partial product is then converted to non-redundant form. The value C is then subtracted from the partial product.

Abstract: A high security tamper evident package for the shipping and storing of a variety of highly proprietary electronic components. The package has a lid and a multi-compartmented base which are threaded together to actively engage an automatic locking system enabled by breakaway tabs on the wall of the base sliding over and engaging behind ramps protruding from the inner surface of the lid. Upon unscrewing the base from the lid, the tabs break off as pressure is applied by movement against the back of the ramps, leaving permanent evidence of the package having been opened. A textured grip on the bottom of the package provides ease of handling and fits snugly onto a raised ring on the top of another package to allow for easy stacking and efficient storage.

Abstract: The present invention discloses a method of measuring magnetic fields on magnetically recorded media. The method entails replacing the metal tip typically used with a scanning tunneling microscope with a flexible thin-film nickel of iron magnetic probe. The present invention describes a mathematical equation that relates probe position to magnetic field strength. In order to establish a tunneling current between the magnetic probe and the magnetically recorded media, any protective layer on the magnetically recorded media is removed. The magnetic probe and the magnetically recorded media may be coated with at least three-hundred angstroms of gold in order to reduce spurious probe deflections due to oxide growths on either the magnetic probe or the magnetically recorded media. The scanning tunneling microscope is designed to maintain a constant tunneling current between the probe and the item being scanned.

Abstract: This invention describes a nonlinear comb filter device and a method for removing harmonic interference from a corrupted signal. Here, a corrupted signal is defined as a signal containing an impulsive signal and harmonic interference. The corrupted signal is delayed through a delay line. The delay line has a plurality of tapped output terminals each spaced at a delay time that is a multiple of the fundamental period of the harmonic interference. An odd number of taps is preferred for ease of sampling and ease of performing certain nonlinear functions such as a median. Each delay line tap is connected to a corresponding input to a nonlinear device. A median device is one possible embodiment of a nonlinear device. The delay line and the nonlinear device extract the harmonic interference from the corrupted signal.

Abstract: Reverse engineering of integrated circuit devices is prevented by denying visual access to the topology of an integrated circuit device. Visual access is denied by coating the device with an opaque ceramic. The opaque ceramic is produced by first mixing opaque particulate with a silica precursor. The mixture is then applied to the surface of the integrated circuit device. The coated device is heated to a temperature in the range of 50.degree. C. to 450.degree. C. in an inert environment for a time within the range of 1 second to 6 hours to allow the coating to flow across the surface of the device without ceramifying. The coated device is then heated to a temperature in the range of 20.degree. C. to 1000.degree. C. in a reactive environment for a time in the range of 2 to 12 hours to allow the coating to ceramify.

Abstract: A method is disclosed for encoding signals for transmission to provide signals which simultaneously have specifiable autocorrelation properties and low predictability. To enhance the accuracy of time of arrival measurements in the presence of either noise or multipath due to skywaves in systems such as LORAN, the coding method provides for low autocorrelation function values at time offsets approximately equal to the expected delay between direct waves and skywaves. This is accomplished by constructing the codeword which is used to encode the signal, from an Nth difference constant ratio codeword, where the expected time delay is equal to N-bits. The constant ratio codewords and the transmitted codewords are both pseudo-randomly generated, resulting in a transmitted signal having very low predictability to an unintended recipient, thereby considerably reducing the effectiveness of attempts at jamming or other electronic countermeasures attacks.

Abstract: An apparatus is described which detects the presence or absence of coherent light and provides an estimate of the coherent light's wavelength. The apparatus employs a common-path "polarization interferometer" in which the two linear polarization paths act as interferometer legs. Electro-optic modulation is used to effect periodic differential path length changes in the interferometer. The apparatus performs synchronous time-integrating detection on the light emerging from the interferometer to measure coherent contributions in the presence of obscuring incoherent light.

Abstract: An apparatus for producing multiple independent binary bit streams from a single underlying key stream. The output from a high speed key generator is fed serially into a multistage shift register. At preselected intervals, the contents of the register are parallel dumped and logically combined with a stored binary word to generate a binary bit which is gated to an output. A plurality of linearly independent binary bit streams result when the register contents are combined with a plurality of linearly independent binary words, one word for each output.

Abstract: A three-mode seat for a motor vehicle cooperable with an adult seat belt assembly to provide three modes of operation including an adult seat mode, a large child booster seat mode, and a small child mode. The seat includes a child's seat module arranged to be secured to the seat back frame between the space provided between two side cushions. The module includes a rigid back panel which carries a cushion assembly and a child's seat belt assembly.

Abstract: A method and apparatus for secure, fast storage and retrieval of information relative to a storage device without interactive checking is characterized by the use of a unique variable range adder. The variable range adder automatically modifies addresses to the storage device and causes data storage and retrieval to conform to the Bell and LaPadula security model, independently of software.

Abstract: A fuser roll including a hollow cylinder having a relatively thin wall, the cylinder being a plastic composition reinforced with a conductive fiber filler, the plastic composition having a resistivity between 0.5 and 0.05 ohm.cm, the cylinder having an outside and an inside surface and enclosing ambient air, a back up roll disposed in an engaging relationship with the outside surface of the hollow cylinder defining said nip, a heating element disposed within said relatively thin wall, the heating element being said conductive fiber filler, the conductive fiber filler also providing the mechanical reinforcement of the hollow cylinder, and an additive, the additive being part of the plastic composition, the additive providing a release layer on the outside surface of the cylinder, the additive being a fluorocarbon at approximately 0.25 percent by weight.

Abstract: An outer product shearing interferometer for an optical source of one-dimensional extent which provides interference between every two points on the source. The interferometer comprises an input plane containing the source, an output plane for observing the outer product, a hologram which imparts the sum of two contributions whose phases are bilinear functions of the spatial coordinates, a two-dimensional Fourier transform system which illuminates the hologram with the transform of light from the input plane, and a one-dimensional Fourier transform system which takes light from the hologram and illuminates the output plane.