Patents by Inventor Yutaka Otsu

Yutaka Otsu 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).

  • Data decompression/decryption method and system
    Patent number: 6411714
    Abstract: An information processing system including a data input means (203, 208, 217, 219) for inputting or receiving data, a data compressing means (206) for compressing the data, a decompressing means (221) for decompressing the compressed data and a main storage (209, 222) is provided with an encrypting means (207) for encrypting the data and a decrypting means (220) for decrypting the encrypted data.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: June 25, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Yoshiura, Kazuo Takaragi, Yusuke Hino, Yutaka Otsu
  • Data compression/encryption method and system
    Patent number: 6122378
    Abstract: An information processing system including a data input means (203, 208, 217, 219) for inputting or receiving data, a data compressing means (206) for compressing the data, a decompressing means (221) for decompressing the compressed data and a main storage (209, 222) is provided with an encrypting means (207) for encrypting the data and a decrypting means (220) for decrypting the encrypted data.
    Type: Grant
    Filed: March 5, 1998
    Date of Patent: September 19, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Yoshiura, Kazuo Takaragi, Yusuke Hino, Yutaka Otsu
  • Method of and apparatus for compressing and decompressing data and data processing apparatus and network system using the same
    Patent number: 5872530
    Abstract: In a data compression method using dictionaries, there are adopted a dynamic dictionary and a static dictionary to prevent the deterioration in the data compression ratio in the leading portion of the input data which cannot be efficiently compressed using the dynamic dictionary. Moreover, the configuration removes the disadvantage of the deterioration in the data compression ratio because character strings having a low appearance frequency occupy a large portion of the dictionary. Data to be compressed is inputted via an input unit to be decomposed into input bit strings 202. Using the input bit string as a retrieval key, a bit string retrieval is conducted through the static dictionary by a decision unit and a reference unit.
    Type: Grant
    Filed: January 28, 1997
    Date of Patent: February 16, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Seiichi Domyo, Hiroshi Yoshiura, Yoshiaki Hattori, Yutaka Otsu, Hiromasa Murakami
  • Communication system
    Patent number: 5854841
    Abstract: Data is compressed/encrypted for communication between application programs without addition of any modification to the application programs. In a communication system where a plurality of personal computers are connected to each other using communication lines, a personal computer is provided with a communication program and an application program, the application program uses a command offered by the communication program for transmission and reception of data with another personal computer, a hooking program for discriminating the command related to the data communication issued by the application program is provided and, after the hooking program has compressed or encrypted the data of application program depending on a type of the command, the command is transferred to the communication program.
    Type: Grant
    Filed: November 25, 1996
    Date of Patent: December 29, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Yukio Nakata, Susumu Matsui, Yasuhiro Takahashi, Takeshi Kondou, Yutaka Otsu