Li Zhang

6957357, Oct 18, 2005

Jul 31, 2001

09/920138

Zhen Liu - Tarrytown NY, US
Cathy Honghui Xia - White Plains NY, US
Li Zhang - Yorktown Heights NY, US

International Business Machines Corporation - Armonk NY

G06F001/04

713503, 713400

A method, computer program product, and data processing system for estimating and correcting the amount of clock skew in end-to-end network timing measurements is disclosed. Measured delays are combined with their time of measurement to create ordered pairs. These ordered pairs represent points within a Cartesian plane. The convex hull of these points is determined, and an optimal line segment from the resulting polygon is selected and extrapolated to create an affine function estimating clock skew over time. The optimal line segment of the polygon is one that optimizes a selected objective function. The objective function is selected so as to be an appropriate measurement of the accuracy of the resulting linear function as an estimate of the actual clock skew.

7194649, Mar 20, 2007

May 29, 2002

10/157610

Zhen Liu - Tarrytown NY, US
Cathy Honghui Xia - White Plains NY, US
Li Zhang - Yorktown Heights NY, US

International Business Machines Corporation - Armonk NY

G06F 1/12

713400, 713375, 713503

Several algorithms are provided to estimate and remove relative clock skews from delay measurements based on the computation of convex hulls. The algorithms are linear in the number of measurement points for the case with no clock resets. For the more challenging case with clock resets, i. e. , the clocks are reset to some reference times during the measurement period, linear algorithms are provided to identify the clock resets and derive the best clock skew lines. The algorithms are also extended to environments in which at least one of the clocks is controlled by Network Time Protocol. These algorithms can also be extended for active clock synchronization to replace or further improve Network Time Protocol.

7272707, Sep 18, 2007

May 19, 2004

10/849357

Zhen Liu - Tarrytown NY, US
Mukund Raghavachari - Baldwin Place NY, US
Bowei Xi - Beijing, CN
Cathy Honghui Xia - Croton-on-Hudson NY, US
Li Zhang - Yorktown Heights NY, US

International Business Machines Corporation - Armonk NY

G06F 15/177

713 1, 707 3, 706 19, 718102, 709223

In one embodiment, the present invention is a method and apparatus for automatic system parameter configuration for performance improvement. One embodiment of the inventive method involves formulating a black box optimization problem, and solving the optimization problem using an enhanced smart hill climbing method. The smart hill climbing method includes both a global and a more precise local search to identify an optimal solution. In one embodiment, one or both of the global and local searches employs a weighted Latin Hypercube Sampling method in combination with importance sampling techniques to yield improved search results.

7296256, Nov 13, 2007

Oct 20, 2003

10/689807

Zhen Liu - Tarrytown NY, US
Petar Momcilovic - New York NY, US
Honghui Xia - Croton-on-Hudson NY, US
Li Zhang - Yorktown Heights NY, US

International Business Machines Corporation - Armonk NY

G06F 9/44
G06F 9/45

717104, 717149, 717154

Method for modeling the performance of an Information Technology system are disclosed. The method includes the steps of receiving performance data of the system; receiving data of transaction flows and system topology; and inferring service demand parameters based on the received data. If closed form expressions are available to characterize the system, an optimization algorithm based on minimum distance between predicted and measured response times and may be used to obtain the performance parameters. Alternatively, a discrete event simulator together with a set of meta-heuristic search methods may be applied to obtain the optimized performance parameters.

7490234, Feb 10, 2009

Aug 3, 2007

11/833345

Zhen Liu - Tarrytown NY, US
Mukund Raghavachari - Baldwin Place NY, US
Bowei Xi - Beijing, CN
Cathy Honghui Xia - Croton-on-Hudson NY, US
Li Zhang - Yorktown Heights NY, US

International Business Machines Corporation - Armonk NY

G06F 15/177
G06F 7/08

713 1, 713100, 707 3, 706 19

In one embodiment, the present invention is a method and apparatus for automatic system parameter configuration for performance improvement. One embodiment of the inventive method involves formulating a black box optimization problem, and solving the optimization problem using an enhanced smart hill climbing method. The smart hill climbing method includes both a global and a more precise local search to identify an optimal solution. In one embodiment, one or both of the global and local searches employs a weighted Latin Hypercube Sampling method in combination with importance sampling techniques to yield improved search results.

7593353, Sep 22, 2009

Mar 13, 2004

10/800305

Zhen Liu - Tarrytown NY, US
Anton Riabov - New York NY, US
Li Zhang - Yorktown Heights NY, US

International Business Machines Corporation - Armonk NY

H04L 12/28

370256, 370390, 370432

A method for constructing an overlay multicast tree to deliver data from a source to an identified group of nodes is provided in which a plurality of nodes are identified and mapped into multidimensional Euclidean space. A geometric region is constructing having a size that is the minimum size necessary to contain the source and all the nodes. Once constructed, a tree is created beginning at the source and including all of the nodes within the geometric region.

7720284, May 18, 2010

Sep 8, 2006

11/517485

Li Zhang - Los Angeles CA, US
Haizhou Ai - Beijing, CN
Shuichiro Tsukiji - Kyoto, JP
Shihong Lao - Kyoto, JP

Omron Corporation - Kyoto
Tsinghua University - Beijing

G06K 9/34

382173

Method and apparatus for face alignment by building a hierarchical classifier network. The hierarchical classifier network connects the tasks of face detection and face alignment into a smooth coarse-to-fine procedure. Texture classifiers are trained to recognize feature texture at different scales for different resolution layers. A multi-layer structure is employed to organize the texture classifiers, which begins with one classifier at the first layer and gradually refines the localization of feature points using additional texture classifiers in subsequent layers.

7739099, Jun 15, 2010

Dec 22, 2005

11/315692

Zhen Liu - Tarrytown NY, US
Honghui (Cathy) Xia - Briarcliff Manor NY, US
Fan Zhang - North Bergen NJ, US
Li Zhang - Yorktown Heights NY, US

International Business Machines Corporation - Armonk NY

G06F 7/60
G06F 9/45
G06F 11/30
G06F 15/173
G06F 9/44

703 22, 703 2, 702182, 709223, 717104

A system and method for performance modeling for an information technology (IT) system having a server(s) for performing a number of types of transactions includes receiving data for system topology and transaction flows and receiving performance measurement data for the IT system. The measurement data is clustered into multiple regimes based on similarities. Service demand and network delay parameters may be inferred based on clustered data.