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).
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Patent number: 7904840Abstract: 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: GrantFiled: October 26, 2007Date of Patent: March 8, 2011Assignee: International Business Machines CorporationInventor: Xiaoping Tang
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Patent number: 7895562Abstract: 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: GrantFiled: December 18, 2007Date of Patent: February 22, 2011Assignee: International Business Machines CorporationInventors: Michael S. Gray, Matthew T. Guzowski, Kevin W. McCullen, Xiaoping Tang, Robert F. Walker, Xin Yuan
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Patent number: 7761818Abstract: 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: GrantFiled: July 25, 2007Date of Patent: July 20, 2010Assignee: International Business Machines CorporationInventors: Michael S. Gray, Xiaoping Tang, Xin Yuan
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Publication number: 20100153892Abstract: 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: ApplicationFiled: February 25, 2010Publication date: June 17, 2010Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Michael S. Gray, Xiaoping Tang, Xin Yuan
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Publication number: 20090176278Abstract: 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: ApplicationFiled: December 1, 2006Publication date: July 9, 2009Applicant: NEOSE TECHNOLOGIES, INC.Inventors: Shawn Defrees, Xiaoping Tang
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Publication number: 20090158223Abstract: 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: ApplicationFiled: December 18, 2007Publication date: June 18, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Michael S. Gray, Matthew T. Guzowski, Kevin W. McCullen, Xiaoping Tang, Robert F. Walker, Xin Yuan
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Publication number: 20090031259Abstract: 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: ApplicationFiled: July 25, 2007Publication date: January 29, 2009Inventors: Michael S. Gray, Xiaoping Tang, Xin Yuan
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Publication number: 20080313577Abstract: 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: ApplicationFiled: July 31, 2008Publication date: December 18, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Xiaoping TANG, Xin Yuan
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Patent number: 7437691Abstract: 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: GrantFiled: April 11, 2006Date of Patent: October 14, 2008Assignee: International Business Machines CorporationInventors: Xiaoping Tang, Xin Yuan
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Publication number: 20080046854Abstract: 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: ApplicationFiled: October 26, 2007Publication date: February 21, 2008Applicant: International Business Machines CorporationInventor: Xiaoping Tang
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Patent number: 7305641Abstract: 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: GrantFiled: January 12, 2005Date of Patent: December 4, 2007Assignee: International Business Machines CorporationInventor: Xiaoping Tang
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Publication number: 20070240088Abstract: 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: ApplicationFiled: April 11, 2006Publication date: October 11, 2007Inventors: Xiaoping Tang, Xin Yuan
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Publication number: 20060156265Abstract: 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: ApplicationFiled: January 12, 2005Publication date: July 13, 2006Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventor: Xiaoping Tang
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Patent number: 6867194Abstract: 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: GrantFiled: August 9, 2001Date of Patent: March 15, 2005Assignee: Wayne State UniversityInventors: Peng George Wang, Xuejun Wu, Xiaoping Tang
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Publication number: 20030050256Abstract: 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: ApplicationFiled: August 9, 2001Publication date: March 13, 2003Inventors: Peng George Wang, Xuejun Wu, Xiaoping Tang