Patents Assigned to NEC USA, Inc.
  • Patent number: 6415282
    Abstract: A method and apparatus for providing a user interface for refining a query applied to a database of images, where a Query Result Visualization Environment allows the user to organize the search results using various techniques. For example, the search results may be clustered on the basis of text, image or URL. The members of the resulting clusters may then be utilized by the user to refine the query to be applied to the database of images.
    Type: Grant
    Filed: April 22, 1998
    Date of Patent: July 2, 2002
    Assignee: NEC USA, Inc.
    Inventors: Sougata Mukherjea, Kyogi Hirata, Yoshinori Hara
  • Patent number: 6408005
    Abstract: A Dynamic Rate Control (DRC) scheduler for scheduling cells for service in a generic Asynchronous Transfer Mode (ATM) switch is disclosed. According to the inventive DRC, each traffic stream associated with an internal switch queue is rate-shaped according to a rate which consists of a minimum guaranteed rate and a dynamic component computed based on congestion information within the switch. While achieving high utilization, DRC guarantees a minimum throughput for each stream and fairly distributes unused bandwidth. The distribution of unused bandwidth in DRC can be assigned flexibly, i.e., the unused bandwidth need not be shared in proportion to the minimum throughput guarantees, as in weighted fair share schedulers. Moreover, an effective closed-loop QoS control can be built into DRC by dynamically updating a set of weights based on observed QoS. Another salient feature of DRC is its ability to control congestion internal congestion at bottleneck points within a multistage switch.
    Type: Grant
    Filed: September 5, 1997
    Date of Patent: June 18, 2002
    Assignee: NEC USA, Inc.
    Inventors: Ruixue Fan, Brian L. Mark, Gopalakrishnan Ramamurthy
  • Patent number: 6404738
    Abstract: A new concept of soft quality-of-service (soft-QoS) is developed that bridges the gap between the efficient provision of network-level QoS and the requirements of multimedia applications. Soft-QoS is defined by a satisfaction index (a number that rates users' perceptual quality) and a softness profile (a function that captures the robustness of multimedia applications to network congestion). Another aspect of this invention is a bandwidth allocation scheme for multimedia applications with soft-QoS requirements is presented. The implementation of the bandwidth allocation scheme on a network element realizes a soft-QoS controller. The controller uses the connections' softness profiles to compute a bandwidth allocation that maximizes the minimum satisfaction index of active connections.
    Type: Grant
    Filed: January 21, 1998
    Date of Patent: June 11, 2002
    Assignee: NEC USA, Inc.
    Inventors: Daniel Reininger, Rauf Izmailov
  • Patent number: 6396886
    Abstract: An apparatus for receiving a discrete multi-tone signal over a communications channel having an impulse response h(n), energy of the impulse response being substantially concentrated in a first band of samples, the apparatus including: a receiver for receiving the discrete multi-tone signal; and a T coefficient finite impulse response time-domain equalizer included in the receiver, the time-domain equalizer having an output additive noise signal, the T coefficients of the time-domain equalizer being provided such that: (a) energy of an effective impulse response heff(n) of at least the communications channel combined with the time-domain equalizer is substantially concentrated in a second band of V+1 samples, whereby the second band of samples is shorter than the first band of samples; and (b) a variance in a frequency spectrum of the output additive noise signal of the time-domain equalizer is controlled.
    Type: Grant
    Filed: February 12, 1999
    Date of Patent: May 28, 2002
    Assignee: NEC USA, Inc.
    Inventor: Samir Kapoor
  • Patent number: 6393427
    Abstract: A method for constructing and maintaining a navigation tree based on external document classifiers is provided. In one embodiment, based on the returned category labels from the classifiers, a navigation tree is constructed by taking usability and user preferences into consideration. Control parameters and algorithms are provided for inserting into and deleting documents from the navigation tree, and for splitting and merging nodes of the navigation tree, are provided.
    Type: Grant
    Filed: March 22, 1999
    Date of Patent: May 21, 2002
    Assignee: NEC USA, Inc.
    Inventors: Quoc Vu, Wen-Syan Li, Edward Chang
  • Patent number: 6389019
    Abstract: A flexible and scalable architecture and method that implements dynamic rate control scheduling in an ATM switch. The scheduler shapes a large number of streams according to rate values computed dynamically based on switch congestion information. To handle a large range of bit rates, a plurality of timewheels are employed with different time granularities. The streams are assigned dynamically to the timewheels based on computed rate values. The shaper architecture and method support priority levels for arbitrating among streams which are simultaneously eligible to transmit.
    Type: Grant
    Filed: March 18, 1998
    Date of Patent: May 14, 2002
    Assignee: NEC USA, Inc.
    Inventors: Ruixue Fan, Brian L. Mark, Gopalakrishan Ramamurthy, Alexander T. Ishii
  • Publication number: 20020053064
    Abstract: This disclosure teaches a method of Boolean satisfiability checking (SAT) for a circuit. The method comprises identifying inactive clauses in the conjunctive normal (CNF) of the circuit and removing the inactive clauses from the CNF.
    Type: Application
    Filed: June 15, 2001
    Publication date: May 2, 2002
    Applicant: NEC USA, INC.
    Inventors: Aarti Gupta, Zijiang Yang, Anubhav Gupta, Pranav Ashar
  • Patent number: 6378096
    Abstract: A method of solving a test generation problem for sequential circuits is disclosed. The method comprises recursively dividing an original test generation problem into smaller problems, wherein said sub-problems may be dependent while one or more of said dependent sub-problems may have solution-specific independence, finding solutions for said sub-problems, reusing solutions for dependent sub-problems, whenever the dependent sub-problems enjoy solution-specific independence; and identifying a minimal subset of conflicting objectives if a sub-problem that has to be solved to achieve multiple objectives has no solution. A test generation system comprising a computer, said computer having a cpu and memory, said memory comprising instructions capable of implementing components of said system.
    Type: Grant
    Filed: September 3, 1999
    Date of Patent: April 23, 2002
    Assignee: NEC USA, Inc.
    Inventors: Srimat T. Chakradhar, Kiran B. Doreswamy, Surendra K. Bommu, Xijiang Lin
  • Patent number: 6345373
    Abstract: At-speed strategies for testing high speed designs on slower testers. At-speed testing schemes is provided that integrates the tester's speed limitations with the test generation process. Due to constraints placed at the test generation process, these schemes might result in a reduced fault coverage. To increase the fault coverage and reduce the test application time, the slow-fast-slow and at-speed strategies can be combined for testing high speed designs on slower testers. A slow tester that uses test vectors that are generated while taking into account the speed of the tester.
    Type: Grant
    Filed: April 22, 1999
    Date of Patent: February 5, 2002
    Assignees: The University of California, NEC USA. Inc.
    Inventors: Srimat T. Chakradhar, Angela Krstic, Kwang-Ting Cheng
  • Patent number: 6343326
    Abstract: In a method of transmitting an IP packet between a source and a destination through an ATM network which has a node formed by an ATM switch and a packet router, a reception packet or cell is transmitted to the node on an unused or undefined VC and is sent to the packet router in the node. In the packet router, an output port is selected by the use of the unused VC to establish a switched virtual channel in the ATM switch and to transfer each packet through the switched virtual channel after the switched virtual channel is established, as long as the reception packet is sent on the same VCI. Neither signaling nor protocol is needed between the nodes.
    Type: Grant
    Filed: May 18, 1998
    Date of Patent: January 29, 2002
    Assignee: NEC USA, Inc.
    Inventors: Arup Acharya, Rajiv Dighe
  • Patent number: 6324673
    Abstract: The method and apparatus for performing design rule checking on Manhattan structures in VLSI circuit layouts. The method and apparatus provides an edge-endpoint-based technique for checking the geometry and spacing of the VLSI circuit layout. The edge-endpoint-based technique uses a scanline algorithm that detects errors between adjacent structures that do not simultaneously intersect the scanline. The method also provides efficient error compilation. The apparatus allows for the design rules to be changed as the VLSI circuit layout evolves. The apparatus can process the VLSI circuit layout with a single processor, and the apparatus provides for multiple processors to process slices of the VLSI circuit layout, thereby enhancing the speed of the design rule checking over traditional software-only techniques.
    Type: Grant
    Filed: May 28, 1999
    Date of Patent: November 27, 2001
    Assignees: Princeton University, NEC USA, Inc.
    Inventors: Zhen Luo, Margaret Martonosi, Pranav Ashar
  • Patent number: 6324165
    Abstract: A large capacity ATM core switch architecture is disclosed, which supports multiple traffic classes and quality-of-service (QoS) guarantees. The switch supports both real-time traffic classes with strict QoS requirements, e.g., CBR and VBR, and non-real-time traffic classes with less stringent requirements, e.g., ABR and UBR. The architecture also accommodates real-time and non-real-time multicast flows in an efficient manner. The switch consists of a high-speed core module that interconnects input/output modules with large buffers and intelligent scheduling/buffer management mechanisms. The scheduling can be implemented using a novel dynamic rate control, which controls internal congestion and achieves fair throughput performance among competing flows at switch bottlenecks. In the dynamic rate control scheme, flows are rate-controlled according to congestion information observed at bottleneck points within the switch.
    Type: Grant
    Filed: September 5, 1997
    Date of Patent: November 27, 2001
    Assignee: NEC USA, Inc.
    Inventors: Ruixue Fan, Brian L. Mark, Gopalakrishnan Ramamurthy
  • Patent number: 6324679
    Abstract: A method and apparatus for design-for-low-power of register transfer level (RTL) controller/data path circuits that implement control-flow intensive specifications. The method of the invention focuses on multiplexer networks and registers which dominate the total circuit power consumption and reduces generation and propagation of glitches in both the control and data path parts of the circuit. Further the method reduces glitching power consumption by minimizing propagation of glitches in the RTL circuit through restructuring multiplexer networks (to enhance data correlations and eliminate glitchy control signals), clocking control signals, and inserting selective rising/falling delays, in order to kill the propagation of glitches from control as well as data signals. To reduce power consumption in registers, the clock inputs to registers are gated with conditions derived by an analysis of the RTL circuit, ensuring that glitches are not introduced on the clock signals.
    Type: Grant
    Filed: June 1, 1998
    Date of Patent: November 27, 2001
    Assignee: NEC USA, Inc.
    Inventors: Anand Raghunathan, Sujit Dey
  • Patent number: 6317740
    Abstract: A method and apparatus are defined for assigning keywords to media objects in files. The media objects include image, video and audio, for example. Various criteria are used for assigning the keywords, including measuring visual distance, measuring syntactical distance, detecting regular patterns in a table and detecting groups of images.
    Type: Grant
    Filed: December 16, 1998
    Date of Patent: November 13, 2001
    Assignee: NEC USA, Inc.
    Inventors: Sougata Mukherjea, Junghoo Cho
  • Patent number: 6304551
    Abstract: A scheme for determining the usage parameter control (UPC) values for an arbitrary traffic source from observations of its emitted cell stream is disclosed. The UPC values are used in a traffic shaping mechanism based on a dual leaky bucket, which shapes the cell stream by either discarding or delaying cells. The choice of UPC values is a function of the statistical characteristics of the observed cell stream; the user's tolerance for delay prior to the network access point; and the cost incurred on the network side. The chosen UPC values are then negotiated with the network. The source traffic characteristics may change dramatically over time, making the initially negotiated UPC descriptor inappropriate for the entire traffic stream. Hence, a method is disclosed for dynamically renegotiating UPC parameters whenever a predetermined change in traffic characteristics is detected.
    Type: Grant
    Filed: March 21, 1997
    Date of Patent: October 16, 2001
    Assignee: NEC USA, Inc.
    Inventors: Gopalakrishnan Ramamurthy, Brian Lai-Bue Mark
  • Patent number: 6275969
    Abstract: This present invention presents a Common Case Computation (CCC) based design. A computation circuit with reduced power consumption, said computation circuit having a plurality of components. The components include a general purpose circuit, a common case detection circuit and a common case execution circuit. The common case detection circuit detects an occurrence of a common case based on a first subset of primary inputs and a first subset of internal variables for the general purpose circuit, and the common case execution circuit computes a subset of primary outputs of the general purpose circuit based on a second subset of primary inputs for the general purpose circuits and a second subset of internal variables for the general purpose circuit. The first subset of the primary inputs and the first subset of internal variables can be the same as the second subset of primary variables and the second subset of internal variables respectively.
    Type: Grant
    Filed: June 9, 1999
    Date of Patent: August 14, 2001
    Assignee: NEC USA, Inc.
    Inventors: Ganesh Lakshminarayana, Anand Raghunathan
  • Patent number: 6247164
    Abstract: Disclosed is a configurable hardware system and method for implementing instance-specific (per-formula) SAT-solver circuits. A template design is provided for producing these circuits on a per-formula basis. The typical hardware requirements for implementing the invention makes the design amenable to current or next-generation FPGA implementation. Hardware simulations indicate that for many difficult SAT problems, the system according to the invention can offer one to three orders of magnitude speedup over prior art software implementations.
    Type: Grant
    Filed: August 28, 1997
    Date of Patent: June 12, 2001
    Assignees: NEC USA, Inc., Princeton University
    Inventors: Pranav Ashar, Sharad Malik, Margaret Martonosi, Peixin Zhong
  • Patent number: 6240078
    Abstract: An ATM switching architecture for a wireless telecommunications network includes two separate units having different functionality. The first unit performs mobility control, wherein a virtual path which contains all virtual channels of a mobile terminal is switched from a first port associated with a first access point, to a second port connected to a first port of the second unit. The second unit performs a switching operation, wherein the virtual channels of the mobile terminal are distributed from the first port of the second unit to different destination ports of the second unit. In one embodiment, the two units may be dedicated hardware components, and in another embodiment, one single hardware component is functionally separated into two separate units connected by a loopback link.
    Type: Grant
    Filed: August 13, 1998
    Date of Patent: May 29, 2001
    Assignee: NEC USA, Inc.
    Inventors: Thomas Kuhnel, Christopher Varlese
  • Patent number: 6240423
    Abstract: A method and apparatus for querying a database of images, in which the results of the query are based upon a combination of region based image matching and boundary based image matching. Additionally similarity calculations are made between individual results of the query so that the results may be clustered based upon similarity.
    Type: Grant
    Filed: April 22, 1998
    Date of Patent: May 29, 2001
    Assignee: NEC USA Inc.
    Inventor: Kyoji Hirata
  • Patent number: 6223316
    Abstract: A two phase vector restoration technique which extracts a minimal subsequence from a sequence that detects a chosen set of faults is provided. The disclosed vector restoration technique is useful in static compaction of test sequences and in fault diagnosis. An accelerated two phase vector restoration that provides further improvement is also provided. The present invention is a significant improvement over the state of the art in the following ways: (1) a sequence of length n can be restored with only O(n log2n) simulations while known approaches require simulation of O(n2) vectors, (2) a two-step restoration process is used that makes vector restoration practical for large designs, and (3) restoration process for several faults is overlapped to provide significant acceleration in vector restoration. The described vector restoration technique has been integrated into a static test sequence compaction system.
    Type: Grant
    Filed: July 10, 1998
    Date of Patent: April 24, 2001
    Assignee: NEC USA, Inc.
    Inventors: Surendra K. Bommu, Srimat T. Chakradhar, Kiran B. Doreswamy