Patents by Inventor Toai Doan

Toai Doan 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: 10373714
    Abstract: A method and system for automatically determining bed-time periods are disclosed. The method comprises detecting at least one physiological signal, determining a posture angle and an activity level using the at least one detected physiological signal, and determining a bed-time period using both the posture angle and the activity level. The system includes at least one sensor to detect a plurality of physiological signals, a processor coupled to the at least one sensor, and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to detect a posture angle using at least one of the plurality of detected physiological signals and to determine a bed-time period using both the posture angle and the activity level.
    Type: Grant
    Filed: January 27, 2015
    Date of Patent: August 6, 2019
    Assignee: Vital Connect, Inc.
    Inventors: Nandakumar Selvaraj, Toai Doan
  • Publication number: 20180310879
    Abstract: A method and system for determining psychological acute stress are disclosed. In a first aspect, the method comprises detecting a physiological signal using a wireless sensor device, determining a stress feature using a normalized heart rate and a plurality of heart rate variability (HRV) features, wherein the normalized heart rate and the plurality of heart rate variability features are calculated using the detected physiological signal, and determining a stress level using the stress feature to determine the psychological acute stress. In a second aspect, the system comprises a wireless sensor device that includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the wireless sensor device to carry out the steps of the method.
    Type: Application
    Filed: May 22, 2018
    Publication date: November 1, 2018
    Inventors: Alexander CHAN, Ravi NARASIMHAN, Nandakumar SELVARAJ, Toai DOAN
  • Patent number: 9980678
    Abstract: A method and system for determining psychological acute stress are disclosed. In a first aspect, the method comprises detecting a physiological signal using a wireless sensor device, determining a stress feature using a normalized heart rate and a plurality of heart rate variability (HRV) features, wherein the normalized heart rate and the plurality of heart rate variability features are calculated using the detected physiological signal, and determining a stress level using the stress feature to determine the psychological acute stress. In a second aspect, the system comprises a wireless sensor device that includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the wireless sensor device to carry out the steps of the method.
    Type: Grant
    Filed: April 11, 2016
    Date of Patent: May 29, 2018
    Assignee: VITAL CONNECT, INC.
    Inventors: Alexander Chan, Ravi Narasimhan, Nandakumar Selvaraj, Toai Doan
  • Publication number: 20160338640
    Abstract: A method and system for determining psychological acute stress are disclosed. In a first aspect, the method comprises detecting a physiological signal using a wireless sensor device, determining a stress feature using a normalized heart rate and a plurality of heart rate variability (HRV) features, wherein the normalized heart rate and the plurality of heart rate variability features are calculated using the detected physiological signal, and determining a stress level using the stress feature to determine the psychological acute stress. In a second aspect, the system comprises a wireless sensor device that includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the wireless sensor device to carry out the steps of the method.
    Type: Application
    Filed: April 11, 2016
    Publication date: November 24, 2016
    Inventors: Alexander CHAN, Ravi NARASIMHAN, Nandakumar SELVARAJ, Toai DOAN
  • Patent number: 8583991
    Abstract: Embodiments of the present invention provide high density, multi-level memory. Thus, various embodiments of the present invention provide a memory apparatus in accordance with various embodiments of the present invention includes a memory block comprising a plurality of cells, each cell adapted to operate with multi-level signal. Such a memory apparatus also includes a channel block adapted to code data values in accordance with a coding scheme that favorably effects a distribution of the multi-levels of the multi-level signals, and to output the corresponding multi-level signals of the coded data values to the memory block. Other embodiments may be described and claimed.
    Type: Grant
    Filed: July 5, 2012
    Date of Patent: November 12, 2013
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Zining Wu, Toai Doan, Aditya Ramamoorthy
  • Patent number: 8441751
    Abstract: A receiving device may be configured to derive an oversampled dibit pulse response estimate using symbols sampled at substantially the read channel symbol rate of the receiving device. The receiving device may include a data acquisition circuit configured to digitize data derived from a memory medium, a symbol timing loop and read circuit, as well as a dibit pulse estimation circuit configured to estimate the oversampled dibit pulse response using symbols sampled at the read channel rate of the receiving device without disturbing the symbol timing loop and read circuit.
    Type: Grant
    Filed: August 17, 2007
    Date of Patent: May 14, 2013
    Assignee: Marvell International Ltd.
    Inventors: Hongwei Song, Zining Wu, Jingfeng Liu, Toai Doan
  • Patent number: 8441752
    Abstract: A receiving device may be configured to derive an oversampled dibit pulse response estimate using symbols sampled at substantially the read channel symbol rate of the receiving device. The receiving device may include a data acquisition circuit configured to digitize data derived from a memory medium, as well as a dibit pulse estimation circuit configured to estimate the oversampled dibit pulse response using symbols sampled at the read channel rate of the receiving device.
    Type: Grant
    Filed: August 23, 2007
    Date of Patent: May 14, 2013
    Assignee: Marvell International Ltd.
    Inventors: Hongwei Song, Zining Wu, Toai Doan
  • Patent number: 8359498
    Abstract: A method of communicating a bitstream having a characteristic Hamming weight to a destination via a channel comprises determining the characteristic Hamming weight of the bitstream, inverting each bit in the bitstream if the characteristic Hamming weight of the bitstream is below a threshold value and developing an indication of whether the bits in the bitstream are inverted, delivering the bitstream and the indication of whether the bits in the bitstream are inverted to the destination via the channel, and inverting each bit in the bitstream at the destination if the indication indicates that the bits are inverted.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: January 22, 2013
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Toai Doan
  • Patent number: 8219886
    Abstract: Embodiments of the present invention provide high density, multi-level memory. Thus, various embodiments of the present invention provide a memory apparatus in accordance with various embodiments of the present invention includes a memory block comprising a plurality of cells, each cell adapted to operate with multi-level signal. Such a memory apparatus also includes a channel block adapted to code data values in accordance with a coding scheme that favorably effects a distribution of the multi-levels of the multi-level signals, and to output the corresponding multi-level signals of the coded data values to the memory block. Other embodiments may be described and claimed.
    Type: Grant
    Filed: December 21, 2006
    Date of Patent: July 10, 2012
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Zining Wu, Toai Doan, Aditya Ramamoorthy
  • Patent number: 8077419
    Abstract: A read-channel module including a VGA module to amplify a signal based on a variable gain, an ADC module to generate a sample based on the amplified signal, and an AGC module to control the variable gain of the VGA module. A gain adjusting module generates (i) a first gain and (ii) a second gain when an amplitude of the sample is (i) less than or equal to a first predetermined threshold and (ii) greater than or equal to a second predetermined threshold, respectively. The AGC module (i) increases and (ii) decreases the variable gain of the VGA module based on (i) the first gain and (ii) the second gain, respectively. The gain adjusting module generates the first gain and the second gain by (i) multiplying a present gain of the AGC module by a predetermined multiplier or (ii) adding a predetermined offset to the present gain.
    Type: Grant
    Filed: October 18, 2010
    Date of Patent: December 13, 2011
    Assignee: Marvell International
    Inventors: Vasudev V. Pai, Toai Doan, Hongying Sheng
  • Patent number: 7817366
    Abstract: A read-channel module includes a variable-gain amplifier (VGA) module, an analog-to-digital converter (ADC) module, an amplitude measuring module, a gain adjusting module, and a zero phase start (ZPS) module. The VGA module has a variable gain, amplifies input signals, and generates amplified signals. The ADC module converts the amplified signals from analog to digital format and generates samples. The amplitude measuring module receives N of the samples and measures amplitudes of the N samples, where N is an integer greater than 1. The gain adjusting module communicates with the amplitude measuring module and selectively adjusts the variable gain of the VGA module based on the amplitudes. The zero phase start (ZPS) module communicates with the amplitude measuring module, receives the samples, and selectively generates phase information from the samples based on the amplitudes.
    Type: Grant
    Filed: May 2, 2007
    Date of Patent: October 19, 2010
    Assignee: Marvell International Ltd.
    Inventors: Vasudev V. Pai, Toai Doan, Hongying Sheng
  • Patent number: 7802151
    Abstract: A communication decoding method comprises receiving processed binary data including a binary code word and an indication of whether bits of the binary code word are inverted and inverting each bit of the binary code word if the indication indicates that the bits are inverted.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: September 21, 2010
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Toai Doan
  • Patent number: 7783937
    Abstract: A method comprises obtaining a first sequence of binary digits that collectively have a characteristic Hamming weight, inverting each of the binary digits in the first sequence of binary digits if the Hamming weight of the first sequence of binary digits is below a predetermined threshold Hamming weight value, and providing an indication of whether the binary digits in the first sequence of binary digits have been inverted.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: August 24, 2010
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Toai Doan
  • Patent number: 7715135
    Abstract: Methods, circuits, and systems for processing a preamble field in a read channel (e.g., in a magnetic storage device such as a hard disk drive). The methods generally include the steps of (a) reading the preamble field, wherein the preamble field comprises a repetitive bit pattern having a logical transition every x bit periods, where x is an integer of at least 3 when d is 0 or 1, or where x is an integer of at least d+2 when d is greater than 1, and (b) processing the repetitive bit pattern. The methods may further relate to processing the preamble for synchronization with the read channel and/or for measuring the fly height of a read/write head. The invention also relates to methods of enabling read channel synchronization and/or fly height measurement.
    Type: Grant
    Filed: June 13, 2006
    Date of Patent: May 11, 2010
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Toai Doan, Zining Wu, Michael Madden
  • Patent number: 7535955
    Abstract: Methods, algorithms, software, architectures, systems and circuits for targeting certain dominant error types in an adaptive FIR filter and/or signal equalizer. The method and algorithm generally include processing a data sequence in accordance with the adaptive algorithm to produce a processed data sequence, filtering the data sequence to generate a filtered data term for the adaptive algorithm, generating a filtered error term for the adaptive algorithm from at least the processed data sequence, and updating the adaptive algorithm in response to the filtered data and error terms. The architectures generally include an equalizer configured to equalize and/or filter a data sequence and provide an equalized data output, a first filter configured to receive the data sequence and generate a filtered data term for the adaptive algorithm, and an error term circuit configured to receive the equalized data output and provide a filtered error term for the adaptive algorithm.
    Type: Grant
    Filed: July 17, 2003
    Date of Patent: May 19, 2009
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Toai Doan
  • Patent number: 7518820
    Abstract: A fly height control system comprises a measurement circuit that receives M pulses that are based on a predetermined pattern stored on a storage medium and that determines a first amplitude and a second amplitude for each of the M pulses, where M is an integer greater than one. The first amplitude is determined at a first time and the second amplitude is determined at a second time that is different than the first time. A calculation circuit determines a distance between a head and a storage medium based on a function of the first amplitudes for the M pulses and the second amplitudes for the M pulses. A head controller controls the head based on the distance determined by the calculation circuit.
    Type: Grant
    Filed: April 11, 2008
    Date of Patent: April 14, 2009
    Assignee: Marvell International, Ltd.
    Inventors: Zining Wu, Toai Doan
  • Patent number: 7359139
    Abstract: A fly height control system comprises a measurement circuit that measures a first amplitude of a pulse, which is based on a predetermined pattern recorded on a storage medium, at a first predetermined time and second amplitudes of the pulse at respective second predetermined times. A calculation circuit estimates a distance between a head and the storage medium based on a function of the first amplitude and the second amplitudes. A head controller that controls the distance between the head and the storage medium based on the estimate.
    Type: Grant
    Filed: January 22, 2007
    Date of Patent: April 15, 2008
    Assignee: Marvell International Ltd.
    Inventors: Zining Wu, Toai Doan
  • Patent number: 7199961
    Abstract: One embodiment features a method, apparatus, and computer-readable media comprising receiving a pulse generated in response to a transition of a head over a predetermined pattern on a storage medium; measuring a first amplitude of the pulse at a first predetermined time and one or more second amplitudes of the pulse at respective second predetermined times; and calculating a distance between the head and the storage medium based on a function of the first and second amplitudes. Another embodiment features a method, apparatus, and computer-readable media comprising receiving a pulse generated in response to a transition of a head over a predetermined pattern on a storage medium; measuring a first amplitude of a power spectrum of the pulse at a first predetermined frequency and a second amplitude of the power spectrum of the pulse at respective second predetermined frequencies; and calculating a distance between the head and the storage medium based on a function of the first and second amplitudes.
    Type: Grant
    Filed: September 24, 2003
    Date of Patent: April 3, 2007
    Assignee: Marvell International Ltd.
    Inventors: Zining Wu, Toai Doan
  • Patent number: 7149955
    Abstract: A Hamming weight encoder includes an input that receives user data including P symbols and a Hamming weight module that determines a Hamming weight of N of said P symbols. N and P are integers greater than one and N is less than or equal to P. The Hamming weight encoder also includes a comparing module that compares the Hamming weight to a Hamming weight threshold and an inverting module that selectively bitwise inverts bits in said N symbols based on said comparison.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: December 12, 2006
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Toai Doan
  • Patent number: 7136250
    Abstract: A method comprising receiving a pulse generated in response to a transition of a head over a predetermined pattern on a storage medium, measuring a first amplitude of a power spectrum of the pulse at a first predetermined frequency and a second amplitude of the power spectrum of the pulse at respective second predetermined frequencies, and calculating a distance between the head and the storage medium based on a function of the first and second amplitudes.
    Type: Grant
    Filed: April 12, 2005
    Date of Patent: November 14, 2006
    Assignee: Marvell International Ltd.
    Inventors: Zining Wu, Toai Doan