Patents by Inventor Xiaoping Tang

Xiaoping Tang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7895562
    Abstract: An adaptive weighting method for layout optimization differentiates different priorities by assigning the weight of a higher priority (pi) to be multiple of the weight of a lower priority (pi?1) where W(pi)=mi % W(pi?1. To avoid numerical imprecision, this method keeps the total cost in the objective function within a trustable range by scaling the initial weights in the objectives, while maintaining relativity, to produce the scaled weights.
    Type: Grant
    Filed: December 18, 2007
    Date of Patent: February 22, 2011
    Assignee: International Business Machines Corporation
    Inventors: Michael S. Gray, Matthew T. Guzowski, Kevin W. McCullen, Xiaoping Tang, Robert F. Walker, Xin Yuan
  • Patent number: 7761818
    Abstract: An approach that obtains a feasible integer solution in a hierarchical circuit layout optimization is described. In one embodiment, a hierarchical circuit layout and ground rule files are received as input. Constraints in the hierarchical circuit layout are represented as an original integer linear programming problem. A relaxed linear programming problem is derived from the original integer linear programming problem by relaxing integer constraints and using relaxation variables on infeasible constraints. The relaxed linear programming problem is solved to obtain a linear programming solution. A subset of variables from the relaxed linear programming problem is rounded to integer values according to the linear programming solution. Next, it is determined whether all the variables are rounded to integer values. Unrounded variables are iterated back through the deriving of the integer linear programming problem, solving of the relaxed linear programming problem, and rounding of a subset of variables.
    Type: Grant
    Filed: July 25, 2007
    Date of Patent: July 20, 2010
    Assignee: International Business Machines Corporation
    Inventors: Michael S. Gray, Xiaoping Tang, Xin Yuan
  • Publication number: 20100153892
    Abstract: An approach that obtains a feasible integer solution in a hierarchical circuit layout optimization is described. In one embodiment, a hierarchical circuit layout and ground rule files are received as input. Constraints in the hierarchical circuit layout are represented as an original integer linear programming problem. A relaxed linear programming problem is derived from the original integer linear programming problem by relaxing integer constraints and using relaxation variables on infeasible constraints. The relaxed linear programming problem is solved to obtain a linear programming solution. Variables are then clustered, and at least one variable from each cluster is rounded to an integer value according to the linear programming solution. Next, it is determined whether all the variables are rounded to integer values. Unrounded variables are iterated back through the deriving of the integer linear programming problem, solving of the relaxed linear programming problem, and rounding of a subset of variables.
    Type: Application
    Filed: February 25, 2010
    Publication date: June 17, 2010
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Michael S. Gray, Xiaoping Tang, Xin Yuan
  • Publication number: 20090176278
    Abstract: The present invention provides reaction mixtures comprising a solvent having at least one of an alkoxy ether and/or a polyhydric alcohol for use in reactions with a mutant endoglycoceramidase having enhanced synthetic activity.
    Type: Application
    Filed: December 1, 2006
    Publication date: July 9, 2009
    Applicant: NEOSE TECHNOLOGIES, INC.
    Inventors: Shawn Defrees, Xiaoping Tang
  • Publication number: 20090158223
    Abstract: An adaptive weighting method for layout optimization differentiates different priorities by assigning the weight of a higher priority (pi) to be multiple of the weight of a lower priority (pi?1) where W(pi)=mi % W(pi?1. To avoid numerical imprecision, this method keeps the total cost in the objective function within a trustable range by scaling the initial weights in the objectives, while maintaining relativity, to produce the scaled weights.
    Type: Application
    Filed: December 18, 2007
    Publication date: June 18, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Michael S. Gray, Matthew T. Guzowski, Kevin W. McCullen, Xiaoping Tang, Robert F. Walker, Xin Yuan
  • Publication number: 20090031259
    Abstract: An approach that obtains a feasible integer solution in a hierarchical circuit layout optimization is described. In one embodiment, a hierarchical circuit layout and ground rule files are received as input. Constraints in the hierarchical circuit layout are represented as an original integer linear programming problem. A relaxed linear programming problem is derived from the original integer linear programming problem by relaxing integer constraints and using relaxation variables on infeasible constraints. The relaxed linear programming problem is solved to obtain a linear programming solution. A subset of variables from the relaxed linear programming problem is rounded to integer values according to the linear programming solution. Next, it is determined whether all the variables are rounded to integer values. Unrounded variables are iterated back through the deriving of the integer linear programming problem, solving of the relaxed linear programming problem, and rounding of a subset of variables.
    Type: Application
    Filed: July 25, 2007
    Publication date: January 29, 2009
    Inventors: Michael S. Gray, Xiaoping Tang, Xin Yuan
  • Publication number: 20080313577
    Abstract: A system and method are disclosed for legalizing a flat or hierarchical VLSI layout to meet multiple grid constraints and conventional ground rules. Given a set of ground rules with multiple grid constraints and a VLSI layout (either hierarchical or flat) which is layout-versus-schematic (LVS) correct but may not be ground rule correct, the system and method provide a legalized layout which meets the multiple grid constraints while maintaining LVS correctness and fixing the ground rule errors as much as possible with minimum layout perturbation from the input design. The system and method support multiple grid pitch constraints for hierarchical design, and provide for LVS correctness to be maintained while an on-grid solution possibly with some spacing violations.
    Type: Application
    Filed: July 31, 2008
    Publication date: December 18, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Xiaoping TANG, Xin Yuan
  • Patent number: 7437691
    Abstract: A system and method are disclosed for legalizing a flat or hierarchical VLSI layout to meet multiple grid constraints and conventional ground rules. Given a set of ground rules with multiple grid constraints and a VLSI layout (either hierarchical or flat) which is layout-versus-schematic (LVS) correct but may not be ground rule correct, the system and method provide a legalized layout which meets the multiple grid constraints while maintaining LVS correctness and fixing the ground rule errors as much as possible with minimum layout perturbation from the input design. The system and method support multiple grid pitch constraints for hierarchical design, and provide for LVS correctness to be maintained while an on-grid solution possibly with some spacing violations.
    Type: Grant
    Filed: April 11, 2006
    Date of Patent: October 14, 2008
    Assignee: International Business Machines Corporation
    Inventors: Xiaoping Tang, Xin Yuan
  • Publication number: 20080046854
    Abstract: Disclosed are a method and a system for redistributing white space on an integrated circuit. The method comprises the steps of providing a series of circuit blocks for the integrated circuit, and placing the blocks on the integrated circuit to obtain a predefined optimal wire length. In accordance with the preferred embodiment of the invention, we first show that the problem of placing the blocks to obtain an optimal wire length, can be formulated as linear programming. Then, we find it can be solved by efficient min-cost flow implementation instead of general and slow linear programming. The approach guarantees to obtain the minimum total wire length for a given floorplan topology. We also show that the approach is capable of handling various constraints such as fixed-frame (fixed area), IO pins, pre-placed blocks, boundary blocks, range placement, alignment and abutment, rectilinear blocks, cluster placement, and bounded net delay, without loss of optimality.
    Type: Application
    Filed: October 26, 2007
    Publication date: February 21, 2008
    Applicant: International Business Machines Corporation
    Inventor: Xiaoping Tang
  • Patent number: 7305641
    Abstract: Disclosed are a method and a system for redistributing white space on an integrated circuit. The method comprises the steps of providing a series of circuit blocks for the integrated circuit, and placing the blocks on the integrated circuit to obtain a predefined optimal wire length. In accordance with the preferred embodiment of the invention, we first show that the problem of placing the blocks to obtain an optimal wire length, can be formulated as linear programming. Then, we find it can be solved by efficient min-cost flow implementation instead of general and slow linear programming. The approach guarantees to obtain the minimum total wire length for a given floorplan topology. We also show that the approach is capable of handling various constraints such as fixed-frame (fixed area), IO pins, pre-placed blocks, boundary blocks, range placement, alignment and abutment, rectilinear blocks, cluster placement, and bounded net delay, without loss of optimality.
    Type: Grant
    Filed: January 12, 2005
    Date of Patent: December 4, 2007
    Assignee: International Business Machines Corporation
    Inventor: Xiaoping Tang
  • Publication number: 20070240088
    Abstract: A system and method are disclosed for legalizing a flat or hierarchical VLSI layout to meet multiple grid constraints and conventional ground rules. Given a set of ground rules with multiple grid constraints and a VLSI layout (either hierarchical or flat) which is layout-versus-schematic (LVS) correct but may not be ground rule correct, the system and method provide a legalized layout which meets the multiple grid constraints while maintaining LVS correctness and fixing the ground rule errors as much as possible with minimum layout perturbation from the input design. The system and method support multiple grid pitch constraints for hierarchical design, and provide for LVS correctness to be maintained while an on-grid solution possibly with some spacing violations.
    Type: Application
    Filed: April 11, 2006
    Publication date: October 11, 2007
    Inventors: Xiaoping Tang, Xin Yuan
  • Publication number: 20060156265
    Abstract: Disclosed are a method and a system for redistributing white space on an integrated circuit. The method comprises the steps of providing a series of circuit blocks for the integrated circuit, and placing the blocks on the integrated circuit to obtain a predefined optimal wire length. In accordance with the preferred embodiment of the invention, we first show that the problem of placing the blocks to obtain an optimal wire length, can be formulated as linear programming. Then, we find it can be solved by efficient min-cost flow implementation instead of general and slow linear programming. The approach guarantees to obtain the minimum total wire length for a given floorplan topology. We also show that the approach is capable of handling various constraints such as fixed-frame (fixed area), IO pins, pre-placed blocks, boundary blocks, range placement, alignment and abutment, rectilinear blocks, cluster placement, and bounded net delay, without loss of optimality.
    Type: Application
    Filed: January 12, 2005
    Publication date: July 13, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventor: Xiaoping Tang
  • Patent number: 6867194
    Abstract: Sugar-modified SIN-1 compositions are provided. The compositions are useful for generating NO in response to hydrolytic activity of a glycosidase specific for the O-glycosidic bond between the sugar and SIN-1 moieties. Pharmaceutical compositions containing the sugar-modified SIN-1 compositions and methods of using the compositions are also provided.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: March 15, 2005
    Assignee: Wayne State University
    Inventors: Peng George Wang, Xuejun Wu, Xiaoping Tang
  • Publication number: 20030050256
    Abstract: Sugar-modified SIN-1 compositions are provided. The compositions are useful for generating NO in response to hydrolytic activity of a glycosidase specific for the O-glycosidic bond between the sugar and SIN-1 moieties. Pharmaceutical compositions containing the sugar-modified SIN-1 compositions and methods of using the compositions are also provided.
    Type: Application
    Filed: August 9, 2001
    Publication date: March 13, 2003
    Inventors: Peng George Wang, Xuejun Wu, Xiaoping Tang