Patents Assigned to BBN Corporation
  • Patent number: 6604432
    Abstract: The in-situ measurement of the shear modulus of a surface layer of soil (12) is performed by apparatus in which a contact foot (11) with a preselected downward bias force engages a defined area of a region of soil. A drive transducer (13) shakes the contact foot (11) vertically and sensing transducers (17, 18) determine the force applied to the foot (11) and the resulting movement of the foot (11) and generate respective first and second output signals. The in-phase movement responsive output signal is analyzed in relation to the force signal to obtain a measurement of a single parameter which is representative of the stiffness provided by the soil (12). The shear modulus as well as the void ratio of the soil can be calculated from the stiffness. The drive transducer (13) is energized by an a.c.
    Type: Grant
    Filed: May 2, 2000
    Date of Patent: August 12, 2003
    Assignee: BBN Corporation
    Inventors: William R. Hamblen, Frank Berkman, Bill Watters
  • Patent number: 6594468
    Abstract: In the communications network disclosed herein, each of a plurality of similar stations is operated so that the group automatically organizes or configures itself into a multi-layered network for relaying messages from station to station, with some of the stations operating at a relatively high power level as message gateways for a cluster of stations operating at lower power thereby to form, through the gateways, a network backbone providing longer distance network links. Initially, individual stations attempt to affiliate at a lower power level with an existing cluster gateway and, if that attempt is unsuccessful, the station switches to a higher power level and commences operation as a cluster gateway. Each cluster gateway periodically communicates data at least identifying to other cluster gateways the non-gateway stations which are affiliated with it.
    Type: Grant
    Filed: October 1, 2001
    Date of Patent: July 15, 2003
    Assignee: BBN Corporation
    Inventor: Subramanian Ramanathan
  • Patent number: 6418299
    Abstract: In the communications network disclosed herein, each of a plurality of similar stations is operated so that the group automatically organizes or configures itself into a multi-layered network for relaying messages from station to station, with some of the stations operating at a relatively high power level as message gateways for a cluster of stations operating at lower power thereby to form, through the gateways, a network backbone providing longer distance network links. Initially, individual stations attempt to affiliate at a lower power level with an existing cluster gateway and, if that attempt is unsuccessful, the station switches to a higher power level and commences operation as a cluster gateway. Each cluster gateway periodically communicates data at least identifying to other cluster gateways the non-gateway stations which are affiliated with it.
    Type: Grant
    Filed: September 9, 1998
    Date of Patent: July 9, 2002
    Assignee: BBN Corporation
    Inventor: Subramanian Ramanathan
  • Patent number: 6185210
    Abstract: A system and method for optimizing and managing Qos (Quality of Service) in a network system including a plurality of open point-to-multipoint virtual circuits (VC)s between various endpoint sites, for example in multicast systems. VC optimization includes determining more appropriate set of VC endpoints to reduce oversent data. If below the VC limit, a set of potential VCs is determined, the set excluding combinations with VC connections already open. An estimation or calculation is performed to determined a reduction in oversent data that would occur if that a possible VC was opened. The possible VC with the greatest reduction in oversent data is then opened. Appropriate traffic is moved over to the newly opened VC, and any VCs which no longer have any traffic are closed. If a VC limit is reached for a node, a different optimization technique is used. A set of possible VCs to endpoint sites is determined.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: February 6, 2001
    Assignee: BBN Corporation
    Inventor: Gregory D. Troxel
  • Patent number: 6160892
    Abstract: In the active muffler disclosed herein, a porous flow resistive member defines a wall of a duct carrying a noisy flow, e.g., a jet exhaust. The flow resistive member is characterized by having a flow resistance substantially less than .rho.c, the characteristic impedance of the acoustic medium. Loudspeakers in a chamber on the side of said porous member opposite the duct are actuated to reduce acoustic pressure in the region between the porous member and the loudspeaker, thereby increasing the acoustic flow through the porous member which in turn increases the dissipation of acoustic energy in the duct. The apparatus is particularly effective at low frequencies where a passive dissipative muffler would be of impractical size.
    Type: Grant
    Filed: May 2, 1997
    Date of Patent: December 12, 2000
    Assignee: BBN Corporation
    Inventor: Istvan L. Ver
  • Patent number: 6144638
    Abstract: Systems and methods for providing multiple users with access to a public network like the Internet are provided. A single high bandwidth connection (e.g., fast Ethernet) allows the users to communicate with the public network. Each user is allocated a specific bandwidth and can freely communicate with the public network up to the allocated bandwidth. Additionally, the invention may be remotely configured to change bandwidth allocations.
    Type: Grant
    Filed: May 9, 1997
    Date of Patent: November 7, 2000
    Assignee: BBN Corporation
    Inventors: Thomas Obenhuber, Rodney L. Joffe
  • Patent number: 6128290
    Abstract: The data network disclosed herein utilizes low duty cycle pulsed radio frequency energy to effect bidirectional wireless data communication between a server microcomputer unit and a plurality of peripheral units located within short range of the server unit, e.g. within 20 meters. By establishing a tightly synchronized common time base between the units and by the use of sparse codes, timed in relation to the common time base, low power consumption and avoidance of interference between nearby similar systems is obtained.
    Type: Grant
    Filed: October 14, 1997
    Date of Patent: October 3, 2000
    Assignee: BBN Corporation
    Inventor: Philip P. Carvey
  • Patent number: 6104708
    Abstract: The data communications systems disclosed herein accommodates terminals having different throughput capabilities by flexibly allocating cyclicly rotated phases of a common pseudo-noise (P/N) code. Throughput capabilities of the terminals are expressible in multiples of a preselected minimum throughput rate so that a single respective code phase is assigned to any terminal operating at the minimum throughput rate while a plurality of sequential consecutive phases are assigned to each terminal having a capability greater than the minimum throughput rate. One or more unassigned phases are provided between phases assigned to different terminals. Any terminal operating at the minimum throughput rate utilizes all time slot intervals in a predetermined frame interval while terminals of greater capability are assigned time slots in accordance with the amount of data traffic to be carried by that terminal and the number of code phases assigned thereto.
    Type: Grant
    Filed: August 11, 1997
    Date of Patent: August 15, 2000
    Assignee: BBN Corporation
    Inventor: Marcos Antonio Bergamo
  • Patent number: 6052682
    Abstract: A computer assisted method for recognizing and labeling instances of name classes in textual environments is described. The invention receives training text having instances of named-entity classes labeled, from which it generates a database of bigram and unigram occurrences. The invention uses the database of bigram and unigram occurrences to form a two level Hidden Markov Model with single output states at the lower level. The invention also receives a series of input text to be processed and labeled with respect to the name classes, and the invention uses the two level Hidden Markov Model to recognize and label instances of named-entity classes in the input text.
    Type: Grant
    Filed: May 2, 1997
    Date of Patent: April 18, 2000
    Assignee: BBN Corporation
    Inventors: Scott Miller, Daniel M. Bikel, Richard M. Schwartz
  • Patent number: 6049758
    Abstract: A method for reducing the time, cost and apparatus required for monitoring the geometry of the oil/water, oil/gas, or gas/water interface in an underground reservoir. By strategically placing sources and sensors, and by fixing the sensors to the solid earth surface beneath the water, and by knowing the velocity fields in the overburden, the changing edges and geometry of the oil may be determined with significantly reduced data gathering. The strategic positions of the sources and receivers is determined by referencing to the known geometry from past surveys. In addition the velocity of the overburden is known by these prior surveys. In addition, higher resolution of reflectivity areas is achieved by use of sound sources capable of generating higher frequencies compensated for the earth's attenuation and by utilizing long integration times to improve signal to noise ratio. These sound sources can be smaller than prior art sources since they provide directed beams of narrower widths.
    Type: Grant
    Filed: June 16, 1997
    Date of Patent: April 11, 2000
    Assignee: BBN Corporation
    Inventors: Carey D. Bunks, James E. Barger
  • Patent number: 5933525
    Abstract: A language-independent and segment free OCR system and method comprises a unique feature extraction approach which represents two dimensional data relating to OCR as one independent variable (specifically the position within a line of text in the direction of the line) so that the same CSR technology based on HMMs can be adapted in a straightforward manner to recognize optical characters. After a line finding stage, followed by a simple feature-extraction stage, the system can utilize a commercially available CSR system, with little or no modification, to perform the recognition of text by and training of the system. The whole system, including the feature extraction, training, and recognition components, are designed to be independent of the script or language of the text being recognized. The language-dependent parts of the system are confined to the lexicon and training data.
    Type: Grant
    Filed: April 10, 1996
    Date of Patent: August 3, 1999
    Assignee: BBN Corporation
    Inventors: John I. Makhoul, Richard M. Schwartz
  • Patent number: 5848403
    Abstract: An improved Genetic Algorithm scheduling system includes system for encoding and testing hard constraint information. Each resource and task includes an associated capability and constraint indicating component. A comparison of the capability and constraint components provides an indication of the associated resource is capable of perform the proposed task. The system also includes a method of creating genomes using cost factors and weight settings to produce initial genomes which encode at least partly optimized schedules. The weight settings can be manipulated to emphasize different cost factors during genomes creation. This method also allows changes to be added into a running GA scheduling system, in that new or changed tasks and new or changed resources are encoded into the genome population.
    Type: Grant
    Filed: April 11, 1997
    Date of Patent: December 8, 1998
    Assignee: BBN Corporation
    Inventors: Daniel C. Gabriner, Stephen D. Milligan, Joseph J. Destefano, David J. Montana
  • Patent number: 5809843
    Abstract: A method and apparatus to cancel gear vibration and noise by imposing a canceling drive torque or force on a driven gear set. Sensors receive information and produce an error signal representative of the vibration and/or noise generated at meshing gears. The error signal indicative of vibration and/or noise information is provided to a control mechanism that processes the noise information to generate a corresponding drive torque. The drive torque corresponding to the noise information is applied to a drive shaft or through a power supply to reduce vibration and noise of the gear assembly at gear meshing frequencies.
    Type: Grant
    Filed: January 7, 1997
    Date of Patent: September 22, 1998
    Assignee: BBN Corporation
    Inventors: James E. Barger, Bruce S. Murray, Daniel L. Nelson
  • Patent number: 5734649
    Abstract: In the data packet router disclosed herein, a matrix of crosspoint switch elements connects data sources to selected destinations during each of a succession of intervals. Allocation of switch elements to desired connections is accomplished by a process which provides a data array having a number of data elements corresponding to the number of switch elements. During each interval, a source is assigned to each of the data elements in accordance with a first current pseudo-random shuffle pattern and a respective destination is assigned to each of the data elements in accordance with a second current pseudo-random shuffle pattern. A new set of shuffle patterns is generated during each interval. An incremental testing is performed across the data array to locate matches not previously allocated and each match found is successively allocated to this switch element corresponding to the data element.
    Type: Grant
    Filed: May 31, 1996
    Date of Patent: March 31, 1998
    Assignee: BBN Corporation
    Inventors: Philip P. Carvey, Thomas F. Clarke
  • Patent number: 5699357
    Abstract: The data network disclosed herein utilizes low duty cycle pulsed radio frequency energy to effect bidirectional wireless data communication between a server microcomputer unit and a plurality of peripheral units, each of which is intended to be carried on the person of the microcomputer user. By establishing a tightly synchronized common time base between the units and by the use of sparse codes, timed in relation to the common time base, low power consumption and avoidance of interference between nearby similar systems is obtained.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: December 16, 1997
    Assignee: BBN Corporation
    Inventor: Philip P. Carvey
  • Patent number: 5682328
    Abstract: Event logging using a single board computer control card configurable onto a backplane containing target processor(s) being monitored. A high resolution clock on the control card time stamps events. Memory on the control card provides a central buffer to store event data, and stores a control program effecting functionality of the card A network interface a facilitates communication with host computer(s) for post processing of event data and to control, communicate with and access the control card. A control program effects event data collection and organization/storage of events in control card memory. The control program coordinates retrieval of events from an event interface area of memory on slave target processors prior to processing by the control card. The control program coordinates offloading of event data from the control card to host computer(s) for post processing by known software visualization tools.
    Type: Grant
    Filed: September 11, 1996
    Date of Patent: October 28, 1997
    Assignee: BBN Corporation
    Inventors: Frederick J. Roeber, Robert E. Hathaway
  • Patent number: 5673236
    Abstract: The underwater sound projector disclosed herein employs, as radiating surfaces or pistons, stiff, lightweight panels whose mass is substantially less than the inertial component of the radiation impedance over the operating frequency range. The panels are driven in opposition by a plurality of linear actuators, e.g., piezoelectric stacks, distributed essentially uniformly over the panels so that each stack drives an essentially equal area of the panel and flexing of the panel is avoided. The compliance reactance of the actuators is made to cancel the inertial reactance of the radiation impedance at all frequencies within an at least decade-wide frequency band. In this way, operation, similar to resonance with its high efficiency, is achieved continuously over a wide frequency band.
    Type: Grant
    Filed: July 2, 1996
    Date of Patent: September 30, 1997
    Assignee: BBN Corporation
    Inventor: James E. Barger
  • Patent number: 5625748
    Abstract: An improved topic discriminator includes an integrated speech recognizer or word and phrase spotter as part of a speech event detector, and a topic classifier trained on topic-dependent event frequencies. The event frequencies are determined from either or both transcribed data with a text event detector and untranscribed speech data with a speech event detector. In accordance with another aspect of the present invention, the phrase spotter is used to detect the presence of phrases without the need of parsing the output of a speech recognizer's hypothesized transcription. In accordance with another aspect of the invention, an improved technique is used to select a subset of the potential speech events on whose event frequencies the topic discrimination decision is made. Finally, in accordance with another aspect of the invention, an improved method of topic modeling is used to improve the performance of the topic discriminator.
    Type: Grant
    Filed: April 18, 1994
    Date of Patent: April 29, 1997
    Assignee: BBN Corporation
    Inventors: John W. McDonough, Herbert Gish, Jan R. Rohlicek, Kenney Ng, Phillippe Jeanrenaud
  • Patent number: 5621859
    Abstract: The invention provides a method of large vocabulary speech recognition that employs a single tree-structured phonetic hidden Markov model (HMM) at each frame of a time-synchronous process. A grammar probability is utilized upon recognition of each phoneme of a word, before recognition of the entire word is complete. Thus, grammar probabilities are exploited as early as possible during recognition of a word. At each frame of the recognition process, a grammar probability is determined for the transition from the most likely preceding grammar state to a set of words that share at least one common phoneme. The grammar probability is combined with accumulating phonetic evidence to provide a measure of the likelihood that a state in the HMM will lead to the word most likely to have been spoken. In a preferred embodiment, phonetic context information is exploited, even before the complete context of a phoneme is known.
    Type: Grant
    Filed: January 19, 1994
    Date of Patent: April 15, 1997
    Assignee: BBN Corporation
    Inventors: Richard M. Schwartz, Long Nguyen