Patents Assigned to Southern Methodist University
  • Patent number: 6782405
    Abstract: The division and square root systems include a multiplier. The systems also include a multipartite table system, a folding inverter, and a complement inverter, each coupled to the multiplier. The division and square root functions can be performed using three scaling iterations. The system first determines both a first and a second scaling value. The first scaling value is a semi-complement term computed using the folding inverter to invert selected bits of the input. The second scaling value is a table lookup value obtained from the multipartite table system. In the first iteration, the system scales the input by the semi-complement term. In the second iteration, the resulting approximation is scaled by a function of the table lookup value. In the third iteration, the approximation is scaled by a value obtained from a function of the semi-complement term and the table lookup value. After the third iteration, the approximation is available for rounding.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: August 24, 2004
    Assignee: Southern Methodist University
    Inventors: David W. Matula, Cristina S. Iordache
  • Patent number: 6693595
    Abstract: A microstrip antenna has first and second cylindrically-shaped dielectric layers having first sides secured together with an array of conducting strips conformally interposed therebetween, the strips being spaced to define a slot between each pair of adjacent strips. A conductive ground plane is disposed on an interior second side of the first dielectric layer, and an array of spaced apart radiating patches are conformally disposed on an exterior second side of the second dielectric layer, each of which patches is positioned over a corresponding slot. Responsive to electromagnetic energy, a high-order standing wave is induced in the antenna and a directed beam is transmitted from and/or received into the antenna.
    Type: Grant
    Filed: April 25, 2002
    Date of Patent: February 17, 2004
    Assignee: Southern Methodist University
    Inventor: Choon Sae Lee
  • Patent number: 6650762
    Abstract: A new approach to data embedding within ITU G.722 and ITU G.711 based upon the method of types and universal classification is disclosed. A secondary data sequence is embedded in the original (host) data stream using the method of types. The embedded data is extracted using a type-based universal receiver, with or without the use of a key. The choice of type and rate for the embedded data is based upon an analysis of portions of the original ITU G.722 or ITU G.711 coded data stream. The universal receiver learns the type from the received data alone, and hence, there is no side information required as in previous data embedding techniques. The embedding process and the receiver may both be data adaptive, so the original data stream can be reconstructed at the decoder without error.
    Type: Grant
    Filed: May 14, 2002
    Date of Patent: November 18, 2003
    Assignee: Southern Methodist University
    Inventors: Jerry Don Gibson, Mark Gavin Kokes, Geoffrey Charles Orsak, Victor James Stolpman
  • Publication number: 20030076245
    Abstract: A new approach to data embedding within ITU G.722 and ITU G.711 based upon the method of types and universal classification is disclosed. A secondary data sequence is embedded in the original (host) data stream using the method of types. The embedded data is extracted using a type-based universal receiver, with or without the use of a key. The choice of type and rate for the embedded data is based upon an analysis of portions of the original ITU G.722 or ITU G.711 coded data stream. The universal receiver learns the type from the received data alone, and hence, there is no side information required as in previous data embedding techniques. The embedding process and the receiver may both be data adaptive, so the original data stream can be reconstructed at the decoder without error.
    Type: Application
    Filed: May 14, 2002
    Publication date: April 24, 2003
    Applicant: Southern Methodist University
    Inventors: Jerry Don Gibson, Mark Gavin Kokes, Geoffrey Charles Orsak, Victor James Stolpman
  • Publication number: 20030055859
    Abstract: An IEEE floating-point adder (FP-adder) design. The adder accepts normalized numbers, supports all four IEEE rounding modes, and outputs the correctly normalized rounded sum/difference in the format required by the IEEE Standard. The latency of the design for double precision is roughly 24 logic levels, not including delays of latches between pipeline stages. Moreover, the design can be easily partitioned into two stages comprised of twelve logic levels each, and hence, can be used with clock periods that allow for twelve logic levels between latches. The FP-adder design achieves a low latency by combining various optimization techniques, including a non-standard separation into two paths, a simple rounding algorithm, unifying rounding cases for addition and subtraction, sign-magnitude computation of a difference based on one's complement subtraction, compound adders, and fast circuits for approximate counting of leading zeros from borrow-save representation.
    Type: Application
    Filed: May 6, 2002
    Publication date: March 20, 2003
    Applicant: Southern Methodist University
    Inventors: Peter-Michael Seidel, Guy Even
  • Publication number: 20030034920
    Abstract: An apparatus and method to reduce the size of a microstrip antenna without sacrificing antenna efficiency too much are described. The antenna structure includes discontinuity of strip width in the middle of the antenna patch to reduce the size of the antenna at a given resonant frequency. The antenna structure further includes a plurality of patches of differing widths connected to each other at junctions. The junctions are placed symmetrically to ensure maximum radiation at the boresight and also to further reduce cross-polarization levels. A coaxial feed is connected at a predetermined location near the center of a patch, having a narrower width, in order to match the input impedance of the antenna to the coaxial feed.
    Type: Application
    Filed: August 9, 2002
    Publication date: February 20, 2003
    Applicant: Southern Methodist University
    Inventor: Choon Sae Lee
  • Patent number: 6281847
    Abstract: An antenna having a dielectric layer configured about a longitudinal axis, and having at least two surface portions which face outwardly from the longitudinal axis in at least two different directions. A conductive ground plane is bonded to each of the at least two surface portions, and at least two conductive antenna elements are bonded to each dielectric layer on each of the at least two surface portions for radiating a signal therefrom. A transmission strip configured for transmitting a signal is connected through a switch to each of the at least two conductive elements.
    Type: Grant
    Filed: December 17, 1999
    Date of Patent: August 28, 2001
    Assignee: Southern Methodist University
    Inventor: Choon S. Lee
  • Patent number: 6133878
    Abstract: A microstrip antenna has two dielectric layers bonded together with an array of conducting strips interposed therebetween, the strips being spaced to define a slot between each pair of adjacent strips. A conductive ground plane is disposed on a first outer side of the two bonded dielectric layers, and an array of radiating patches are disposed on a second outer side of the two bonded dielectric layers, each of which patches is positioned over a corresponding slot, the array of patches being spaced apart to form an aperture between each pair of adjacent patches. Responsive to electromagnetic energy, a high-order standing wave is induced in the antenna and a directed beam is transmitted from and/or received into the antenna.
    Type: Grant
    Filed: July 22, 1998
    Date of Patent: October 17, 2000
    Assignee: Southern Methodist University
    Inventor: Choon Sae Lee
  • Patent number: 6064810
    Abstract: A system (2) predicts the behavior of a component using refinements in both space and time. The system (2) includes a steady-state engine (14) that generates a steady-state stencil (16) that defines successively refined meshes (58, 60, 90, 118, 122) in space. A transient engine (18) adopts the spatial framework of the steady-state stencil (16) to predict the behavior of the component over time. The transient engine (18) may adjust a time interval (356) to refine the predictions in time.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: May 16, 2000
    Assignees: Southern Methodist University, Texas Instruments Incorporated
    Inventors: Peter E. Raad, James S. Wilson, Donald C. Price
  • Patent number: 5896573
    Abstract: Cellular communication systems supporting high utilization geographic regions having extensive cell overlap segments that collectively contain a substantial portion of the mobile units. A system and method for channel assignments incorporating selection from alternative transceivers defining overlapping cells is provided with load balancing to reduce call blocking. The system incorporates selective multiple handoffs responsive to channel assignment requests both to extend load balancing and also to substantially avoid call cutoff when active mobile units cross cell boundaries into possibly saturated cells.
    Type: Grant
    Filed: April 14, 1997
    Date of Patent: April 20, 1999
    Assignee: Southern Methodist University
    Inventors: Cheng Yang, David W. Matula
  • Patent number: 5818391
    Abstract: A microstrip antenna has two dielectric layers bonded together with an array of conducting strips interposed therebetween, the strips being spaced to define a slot between each pair of adjacent strips. A conductive ground plane is disposed on a first outer side of the two bonded dielectric layers, and an array of radiating patches are disposed on a second outer side of the two bonded dielectric layers, each of which patches is positioned over a corresponding slot, the array of patches being spaced apart to form an aperture between each pair of adjacent patches. Responsive to electromagnetic energy, a high-order standing wave is induced in the antenna and a directed beam is transmitted from and/or received into the antenna.
    Type: Grant
    Filed: March 13, 1997
    Date of Patent: October 6, 1998
    Assignee: Southern Methodist University
    Inventor: Choon Sae Lee
  • Patent number: 5672903
    Abstract: A thermal detector includes a transducer layer of semiconducting yttrium barium copper oxide which is sensitive at room temperature to radiation and provides detection of infrared radiation. In a gate-insulated transistor embodiment, a layer of ferroelectric semiconducting yttrium barium copper oxide forms a gate insulator layer and increases capacitance of the transistor or latches the transistor according to the polarization direction of the ferroelectric layer.
    Type: Grant
    Filed: February 26, 1996
    Date of Patent: September 30, 1997
    Assignee: Southern Methodist University
    Inventors: Donald P. Butler, Zeynep Celik-Butler, Pao-Chuan Shan
  • Patent number: 5633915
    Abstract: A multiple-layered cellular communication system particularly adapted to mobile phones and LAN type communication is provided with an overlaid arrangement of cell transceivers. By having this overlay, multiple service providers can provide a cooperative method of load sharing. The usage of the frequency spectrum can be improved and an advanced hand-off arrangement can be used to prevent or reduce the possibility of blocked calls due to cell saturation.
    Type: Grant
    Filed: May 16, 1995
    Date of Patent: May 27, 1997
    Assignee: Southern Methodist University
    Inventors: Cheng Yang, David W. Matula
  • Patent number: 5597817
    Abstract: Cephalosporins with an exocyclic allene in the 7-position and their pharmaceutically active salts are potent inhibitors of .beta.-lactamases and are therefore useful in the treatment of penicillin resistant infections.
    Type: Grant
    Filed: December 9, 1994
    Date of Patent: January 28, 1997
    Assignee: Southern Methodist University
    Inventors: John D. Buynak, Brian Bachmann
  • Patent number: 5572060
    Abstract: A thermal detector includes a transducer layer of semiconducting yttrium barium copper oxide which is sensitive at room temperature to radiation and provides detection of infrared radiation. In a gate-insulated transistor embodiment, a layer of ferroelectric semiconducting yttrium barium copper oxide forms a gate insulator layer and increases capacitance of the transistor or latches the transistor according to the polarization direction of the ferroelectric layer.
    Type: Grant
    Filed: February 1, 1995
    Date of Patent: November 5, 1996
    Assignee: Southern Methodist University
    Inventors: Donald P. Butler, Zeynep Celik-Butler, Pao-Chuan Shan
  • Patent number: 4687828
    Abstract: A water-soluble graft copolymer of lignin-(2-propenamide)-(sodium 2,2-dimethyl-3-imino-4-oxohex-5-ene-1-sulfonate) having a central lignin network and at least one grafted side chain, R, having randomly repeating units of the formula: ##STR1## such that the central lignin network has a molecular weight of about 1,000 to 100,000 and the total number of randomly repeating units in the grafted side chain or chains is in the range of 1,000 to 300,000, such that the total copolymer molecular weight is in the range of 40,000 to 30,000,000.The copolymers of the present invention are useful as thickeners for water and aqueous solutions and may be advantageously used in the recovery of oil from subterranean wells or in the preparation and use of drilling fluid compositions.
    Type: Grant
    Filed: August 30, 1985
    Date of Patent: August 18, 1987
    Assignee: Southern Methodist University
    Inventors: John J. Meister, Damodar R. Patil
  • Patent number: 4564989
    Abstract: A device for use when inserting a tube into or through a rubber stopper, or other resilient sealing member. A rigid body member is provided with one or more holes shaped to support a tube in an upright position, so that a person can manually grip and push a stopper downward over the tube, without the normal difficulty of having to grip both the tube and the stopper at the same time. In a preferred embodiment the body member is also provided with a base to support the body in a stable position on a work bench or the like, and is further provided with a rigid protrusion having a suitable diameter for use in removing the tube from the stopper.
    Type: Grant
    Filed: August 20, 1980
    Date of Patent: January 21, 1986
    Assignee: Southern Methodist University
    Inventor: Franklin Sogandares