Abstract: A method and apparatus for encoding and decoding multi-dimensional signals is disclosed. Non-separable multi-dimensional filters are utilized. Analysis filters encode the signal by applying a windowing function and a reduction function to the multi-dimensional signal. This produces a prototype. The prototype is then replicated as many times as required by utilizing a modulation function. Synthesis filters then decode the encoded signal by utilizing the inverse of the encoding process.

Abstract: A voltage stress (e.g., reverse voltage stress) in rectifying diodes of, for instance, an asymmetrical DC-to-DC converter is reduced by using a transformer circuit having multiple power transformers with a composite static transfer characteristic. More specifically, the static transfer characteristic is selected to be monotonic in combination with the transformer circuit including two transformers, having independent isolated cores, coupling an input to output of the converter. A primary to secondary winding ratio of each of the two transformers is selected in such a way as to achieve a reduction in reverse voltage in at least one of the rectifying diodes. The reduction in the reverse voltage and, hence, improved efficiency of the rectifier is directly translatable into an increase in a power density of the converter.

Abstract: A communication system including a CLOS switching network, and a method for characterizing network capacity, usage, congestion, and blocking and/or near blocking states. The CLOS switching network includes input, center and output stages each comprised of at least one switch, a plurality of first links connecting each input stage switch to each of the center stage switches, and a plurality of second links connecting each center stage switch to each of the output stage switches. The system also comprises a controller for determining the idle/busy status of each of the first and second links, and for calculating a measurement of available paths between each of the input stage switches to each of the output stage switches based on the status of the first and second links.

Abstract: The present invention provides a method for recognizing connected and degraded text embedded in a gray-scale image. In accordance with the invention, pseudo two-dimensional hidden Markov models (PHMMs) are used to represent characters. Observation vectors for the gray-scale image are produced from pixel maps obtained by gray-scale optical scanning. Three components are employed to characterize a pixel: a convoluted, quantized gray-level component, a pixel relative position component, and a pixel major stroke direction component. These components are organized as an observation vector, which is continuous in nature, invariant in different font sizes, and flexible for use in various quantization processes. In this matter, information loss or distortion due to binarization processes is eliminated; moreover, in cases where documents are binary in nature (e.g.

Abstract: A multimedia on-demand server including a randomly-accessible library of multimedia programs (such as movies stored on magnetic or optical disks), a limited amount of RAM to buffer and store selected portions of programs retrieved from the library, and an interface that switchably routes program material from the library and RAM buffers to an audience of viewers. The server employs a restricted retrieval strategy and a novel storage allocation scheme that enable different portions of one or more programs to be continuously retrieved and selectively routed to a large number of on-demand viewers, while at the same time minimizing the amount of the RAM required to effect this service. The on-demand server also responds to viewer-generated commands to control the viewing of a program. In a particular embodiment, these commands include video tape player-like operations such as fast-forward, rewind and pause.

Abstract: An Add/Drop circuit for use in optical wavelength-division multiplexed systems includes fiber coupled four-port polarized beamsplitters and fiber Bragg grating filters.

Abstract: A network interface device includes a weatherable enclosure having injection molded, die cast, or stamped top and bottom cap portions and a body portion which is extruded. The injection molded portions are fabricated from a polymer, such as polyvinyl chloride, with a higher melt index than the grade of polymer used to fabricate the body portion. The body portion has top and bottom openings adapted to receive the top and bottom cap portions. The network interface electrical components are enclosed within the housing.

Abstract: A call-center ACD switch and queuing method are modified either to respond to an arriving call by determining, for those splits that could handle the call, the present values of a parameter that defines what is a best split for handling the call, determining from those present values which split is the best split for handling the call, and then enqueuing the call in the call queue of the best split, or to respond to a call that overflows the call queue of its primary agent split by determining which backup split in which call center is the best backup split for the call, and enqueuing the call in the call queue of the best backup split. Any desirable criteria may be used to determine the best split. A preferred criterion is queue waiting time: the best split is the one whose call queue offers the shortest in-queue waiting time.

Abstract: A method for controlling power losses associated with the operation of line interface circuits in telecommunications networks comprises detecting a loop current of at least one subscriber loop interconnected to at least one line interface circuit. The detected loop current is used to access a threshold voltage value from a line interface circuit database. A threshold voltage based on the threshold voltage value retrieved from the database is compared to a feedback voltage to control a duty cycle of a switching converter circuit in the line interface circuit. Controlling the duty cycle of the switching converter circuit enables control of battery voltages based on the comparison of the threshold voltage and the feedback voltage. In the preferred embodiment, the battery voltage is controlled to be a minimum voltage needed to provide a predetermined magnitude of the minimum loop current.

Abstract: A method for sequentially encrypting the digits of a personal identification number, and an apparatus for practicing the method, are disclosed. According to the method, a random number is generated and supplied to a user requesting access to a system. The user encrypts a digit of his personal identification number by performing a function on the random number and the digit and then provides the encrypted digit to a verification system. A second random number is then generated, provided to the user, applied to encrypt another digit of the user's personal identification number and then input to the verification system. The dialogue between verification system and the user continues, digit by digit, until each digit of the personal identification number has been provided to the verification system in encrypted form. The verification system then compares the encrypted input with the user's personal identification number accessed from memory.

Abstract: A new modem architecture that substantially minimizes the cost of adding features to the modem, and substantially minimizes the time overhead associated with the slave-like interface between the modem controller and the modem signal processor. The architecture enables the signal processor to directly access the controller's memory resources so that the signal processor can make most efficient use of its own internal expensive high-speed memory.

Abstract: The detection and cancellation of echo in a communications system is enhanced by taking advantage of the accumulated knowledge relating to the echo path delay that an adaptive filter acquires as a result of its adaptation process. Such knowledge improves significantly the ability of an associated Near-End-Speech (NES) detector to detect for the presence of near end speech.

Abstract: To prevent particular transmission equipment from artificially increasing low level audio signals to a predetermined allowable level, such signals are first summed with a stabilization signal having a predetermined frequency to form a composite audio signal. Moreover, the stabilization signal has a level that prevents any increase in signal level that may be artificially imposed on the composite signal during the processing of the composite signal by the transmission equipment. Once the composite signal has been so processed, then the stabilization signal is removed therefrom and the original audio signal is outputted to associated transmission media.

Abstract: A process for plating tin or tin alloy onto metal substrates is described. In the process, a metal substrate is placed in an electroplating bath that contains a stannous sulfate and an organic compound additive in which the organic compound has a heterocyclic moiety in an aqueous solution of sulfonic acid. The bath is then subjected to pulse plating conditions that plate a layer of tin or tin alloy onto the metal substrate wherein the tin in the tin layer has a grain size of about 2 .mu.m to about 8 .mu.m. During pulse plating, a current density of about 65 ASF to about 250 ASF is applied to the electroplating bath in a pulsed manner, i.e. the current is cycled on and off during plating. The duty cycle of the pulse is about twenty-five percent to about thirty percent. The duration of the on pulse during the cycle is about 50 .mu.s to about 500 .mu.s.

Abstract: A telephone switching system (100), such as an ACD switching system in a call center, is used to broadcast information for users, such as displayable messages, to telecommunications terminals (110-112, 212), such as display telephones or data terminals, of a plurality of the users, such as call center agents, by means of non-call-associated display messages that are transmitted over the terminals' telephone lines (120-122), at the request of one of the users, such as the supervisor of the call center. The one of the users requests the broadcast either by depressing a predetermined button on their terminal accompanied by dialing a message identifier, or by dialing a feature access code and a message identifier, or by sending an ISDN "userinfo" or DCP "route text message" message that contains the information for users. The switching system uses either stored data or data contained in the request to determine the destinees of the information for users.

Abstract: The invention relates to method and apparatus for computing transitive closure and reachability in directed graphs. These are fundamental graph problems with many applications such as database query optimization. A random rank is applied to each node (or record or element, as the case may be) and the least rank reachable from each such node is determined. This least rank value reachable from a node is highly correlatable to the size of the reachable set. An estimator can therefore be applied to convert the least reachable rank value to an estimate of the size of the reachable set. The accuracy of the estimate can be increased by repeating the random rank assignments together with the least reachable rank determinations and averaging the results.

Abstract: A method of protecting metals from corrosion by applying an alternating voltage to them, thereby reversing the metal's polarity with respect to its surroundings. Particular applications are for metals which are buried in soil or are exposed to an electrolyte. Amphoteric metals Steels, which are subject to hydrogen embrittlement when made cathodic, are also protected by polarity reversal.

Abstract: A method and apparatus for the three dimensional graphical display of information. Information is displayed as nodes and arcs connecting nodes. The nodes and arcs are displayed with their three dimensional characteristics used to encode data attributes. In one embodiment, the nodes and arcs represent geographic network data and are displayed on a representation of a globe. The height of the arcs above or below the surface of the globe encodes a link attribute of the data, while the height of the nodes above or below the surface of the globe encodes a node attribute of the data. Three dimensional characteristics of the nodes and arcs other than height may also be used to encode data attributes. In addition, the three dimensional representation of the data allows for novel thresholding techniques, such as drawing certain nodes and arcs below the surface of the globe and using the globe as a clipping surface.

Abstract: A speech synthesis method employs an acoustic element database that is established from phonetic sequences occurring in an interval of a speech signal. In establishing the database, trajectories are determined for each of the phonetic sequences containing a phonetic segment that corresponds to a particular phoneme. A tolerance region is then identified based on a concentration of trajectories that correspond to different phoneme sequences. The acoustic elements for the database are formed from portions of the phonetic sequences by identifying cut points in the phonetic sequences which correspond to time points along the respective trajectories proximate the tolerance region. In this manner, it is possible to concatenate the acoustic elements having a common junction phonemes such that perceptible discontinuities at the junction phonemes are minimized. Computationally simple and fast methods for determining the tolerance region are also disclosed.