Abstract: A noise-cancelling handset has reduced inter-user variability. The handset includes an earpiece housing. A space, referred to as the "front volume" is defined by the rear and side walls of this housing and a front surface containing acoustic ports for radiation of received sound into the user's ear. An error microphone is situated so as to sample the acoustic field within the front volume. In use, a further volume, referred to as the "forward volume," is defined between the front surface and the user's outer auditory canal. A leaky acoustic seal typically obtains between the front surface and the user's auditory canal. Thus, the forward volume will effectively have an acoustic leak, which has a characteristic, but variable acoustic impedance that is mostly of inductive character. At least one acoustic port is provided to effectuate a controlled leak to the outside of the handset.

Abstract: We disclose apparatus for holographic recording of information. The apparatus includes a lens or lens system, referred to here as the "FT lens," situated in such a way that light from an object beam enters the FT lens after passing through an object, and light leaving the FT lens impinges on a recording medium situated at a Fourier transform plane of the object with respect to the FT lens. In certain aspects of the invention, the apparatus includes a phase element effectively juxtaposed with the object, the phase element is effective for redistributing object-beam intensity in the Fourier transform plane, and the phase element has a correlation length greater than a maximum pixel side length associated with the object. In certain other aspects of the invention, the apparatus includes an optical element or optical system, referred to here as a "power optic," that adds convergence or divergence to the object beam before the object beam enters the FT lens.

Abstract: A signature verification method involves segmenting a smoothed and normalized signature and, for each segment, evaluating at least one local feature, thereby to obtain a feature-value vector. The method further includes computing the likelihood that the segments having the observed sequence of feature values were generated by a particular hidden Markov model, such model comprising a sequence of states having duration probabilities and feature-value histograms. In one aspect, the invention involves explicit state-duration modeling to account for duration in the respective states underlying the unknown signature. In another aspect, the invention involves computing a measure of signature complexity, and setting the number of states of the hidden Markov model according to such complexity measure.

Abstract: A tag and an interrogator exchange proprietary information using Modulated BackScatter (MBS) technology. A method for encrypting the RFID user's PIN and thereby making the interception and the subsequent illegal use of RFID accounts at least as difficult as a present day ATM cards. For example, the encryption method can be based upon the US Digital Encryption Standard (DES), either first or third level. The Tag's personal encryption key is only known by the financial database and the RFID Tag. This method can be applied to any type of financial, debt, identification, or credit card.

Abstract: A videoconferencing network of audiovisual communication terminals is interconnected by a telephone network. Each terminal is activated only when the balance in a user account has been read and the account has been made available for debiting. The terminal includes a monitor system for playing out and receiving voice and picture information, an interface system for conditioning signals passing between the monitor system and the telephone network, and a database which contains the locations and telephone numbers of other terminals of the videoconferencing network. The terminal firer includes a display of information from the database, a pointing device by means of which a user can make a selection from the display by indicating the relevant position in the display, and a device for automatically dialing up the selected remote terminal.

Abstract: An image classifier receives input images and assigns each input image to one of a plurality of image classes. The image classifier includes plural class distribution maps, each based on a plurality of features evaluated on training images, and each representing those feature values that occur at least once among the training images belonging to the corresponding class. The image classifier further includes means for constructing a test map by evaluating the plurality of features on the input image. The image classifier further includes means for comparing the test map to the class distribution maps in order to identify which one of the class distribution maps has the least distance to the test map. At least one of the features is defined according to a rule that relates to the shapes of images of at least one image class. One advantageous method for evaluating features is carried out storing the input pattern, in a digital memory, as a point in a representational space.

Abstract: A method and apparatus are disclosed for enhancing, within a signal bandwidth, a corrupted audio-frequency signal. The signal which is to be enhanced is analyzed into plural sub-band signals, each occupying a frequency sub-band smaller than the signal bandwidth. A respective signal gain function is applied to each sub-band signal, and the respective sub-band signals are then synthesized into an enhanced signal of the signal bandwidth. The signal gain function is derived, in part, by measuring speech energy and noise energy, and from these determining a relative amount of speech energy, within the corresponding sub-band. In certain embodiments of the invention, the signal gain function is also derived, in part, by determining a relative amount of speech energy within a frequency range greater than, but centered on, the corresponding sub-band.

Abstract: A method and apparatus for acoustically monitoring a highway is disclosed which is inexpensive to maintain and install and does not require that the roadway be closed, torn-up or repaved. These results are obtained in an illustrative embodiment of the present invention which comprises a Mill's Cross acoustic array mounted proximate to a highway, spatial discrimination circuitry, frequency discrimination circuitry and interface circuitry that generates a binary signal which indicates when a motor vehicle is, or is not, within a detection zone on the roadway.

Abstract: Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditons. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.

Abstract: Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.

Abstract: Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.

Abstract: An ellipsoidal infinite element is used for the modeling of electromagnetic fields in exterior domains surrounding a structure. This infinite element is based on a multipole expansion that describes scattered and/or radiated fields exterior to the structure. The electromagnetic field is represented in the exterior domain by a pair of scalar potentials, referred to as the Debye potentials.

Abstract: In an improvement over conventional finite element techniques, an ellipsoidal infinite element is used for the modeling of acoustic fields in exterior, fluid-filled domains surrounding a structure. This ellipsoidal infinite element is based on a multipole expansion that describes, to arbitrary accuracy, any scattered and/or radiated field exterior to an ellipsoid. Significantly, the respective eccentricities of the three elliptical cross sections of the ellipsoid can take values that are arbitrary and mutually independent. The ellipsoidal infinite element is readily incorporated in any structural or acoustic finite element code.

Abstract: In certain wireless communication systems, including at least some CDMA cellular systems, short messages can be delivered to mobile stations in a broadcast fashion using a common forward (downlink) channel sometimes referred to as the Paging Channel. Economy in the use of the Paging Channel can be achieved by using so-called slotted mode reception. In accordance with this mode, the infrastructure directs messages to a given mobile station only during time slots allocated to the particular group of mobile stations to which the given station belongs. These time slots recur according to a paging slot cycle having a specified length (expressed as a number of slots), or slot cycle index. Disclosed here is a further cycle, referred to as the Broadcast Paging Cycle, for use in implementing a service for broadcasting short messages (to many mobile stations). The Broadcast Paging Cycle has an index that is larger than, and incommensurable with, the paging slot cycle index.

Abstract: A thermally activated silica optical circuit switch that uses light from a light source, such as a laser, to heat various regions of the switch to produce a switching function. In one embodiment, the switch includes silica glass formed on a substrate, such as a silicon substrate, and at least one input waveguide and one output waveguide formed within the silica glass. A light source is then used to generate light that illuminates a path in the silica glass that couples a particular input waveguide to a particular output waveguide. The light from the light source has a wavelength that enables it to be substantially absorbed by the silica glass and substantially transmitted through the substrate. The illumination by the light increases the temperature and correspondingly the index of refraction of the silica glass in the path. A light signal is then able to travel through the coupled waveguides via the increased index of refraction of the silica glass within the path.

Abstract: An operating system monitoring tool has two components: a hyperkernel that augments the operating system of a target multiprocessing system; and a graphical front end for implementing the user interface. The hyperkernel component is annexed to the operating system by: intercepting all interrupts and redirecting them from the operating system to the hyperkernel; and substituting a jump to the hyperkernel for each point in the operating system that returns back to the application code. Associated with the hyperkernel are buffers, located on the respective processors, that accumulate information pertaining to calls to the operating system. On demand, or when the buffers fill, the accumulated information is relayed to the graphical front end for filtering, manipulation, and display.

Abstract: A videoconferencing network of audiovisual communication terminals is interconnected by a telephone network. Each terminal is activated only when the balance in a user account has been read and the account has been made available for debiting. The terminal includes a monitor system for playing out and receiving voice and picture information, an interface system for conditioning signals passing between the monitor system and the telephone network, and a database which contains the locations and telephone numbers of other terminals of the videoconferencing network. The terminal further includes a display of information from the database, a pointing device by means of which a user can make a selection from the display by indicating the relevant position in the display, and a device for automatically dialing up the selected remote terminal.

Abstract: Coding systems that provide a perceptually improved approximation of the short-term characteristics of speech signals compared to typical coding techniques such as linear predictive analysis while maintaining enhanced coding efficiency. The invention advantageously employs a non-linear transformation and/or a spectral warping process to enhance particular short-term spectral characteristic information for respective voiced intervals of a speech signal. The non-linear transformed and/or warped spectral characteristic information is then coded, such as by linear predictive analysis to produce a corresponding coded speech signal. The use of the non-linear transformation and/or spectral warping operation of the particular spectral information advantageously causes more coding resources to be used for those spectral components that contribute greater to the perceptible quality of the corresponding synthesized speech.

Abstract: A heterojunction bipolar transistor in an integrated circuit has intrinsic and extrinsic base portions. The intrinsic base portion substantially comprises epitaxial silicon-germanium alloy. The extrinsic base portion substantially comprises polycrystalline material, and contains a distribution of ion-implanted impurities. An emitter overlies the intrinsic base portion, and a spacer at least partially overlies the emitter. The spacer overhangs the extrinsic base portion by at least a distance characteristic of lateral straggle of the ion-implanted impurities.

Abstract: An optical communication network includes at least one single-mode fiber, referred to as a "primary fiber," for transmission between a central office and a distribution node, and at least one multiplicity of single-mode fibers, referred to as "distribution fibers," for transmission between the distribution node and a multiplicity of optical network units (ONUs). Transmissions are exchanged between the primary and distribution fibers via at least one optical coupler located at the distribution node. The network is passive in the sense that all monitoring of the transmission media and the ONUs can be performed at the central office, without active intervention at remote locations. The network includes a monitor and a multiplicity of bypass lines by means of which at least a portion of inbound signals from the distribution fibers are transmitted to the monitor without passing through the optical coupler at the distribution node.