Patents by Inventor Akio Tajima

Akio Tajima 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: 11115318
    Abstract: An optical network control device includes: a path setting unit that sets, based on topology information including a connection relationship among a plurality of nodes and a first route selection index value of routes each connecting the plurality of nodes, a first path for a route having the first route selection index value being minimum from among route candidates linking a start point node and an end point node of a requested traffic; a topology information modification unit that calculates a second route selection index value acquired by increasing the first route selection index value of the route that accommodates the first path; and a path selection unit that selects a second path for a route having the second route selection index value being minimum from among the route candidates.
    Type: Grant
    Filed: October 4, 2017
    Date of Patent: September 7, 2021
    Assignee: NEC CORPORATION
    Inventors: Shinsuke Fujisawa, Hitoshi Takeshita, Akio Tajima
  • Patent number: 11109123
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Grant
    Filed: July 9, 2020
    Date of Patent: August 31, 2021
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Publication number: 20210167288
    Abstract: By using a polycyclic aromatic compound as a material for a light-emitting layer, formed by connecting a plurality of aromatic rings with a boron atom and an oxygen, sulfur, or selenium atom, which have been substituted by a specific aryl such as anthracene, an organic EL element having at least one of excellent quantum efficiency and element life can be provided.
    Type: Application
    Filed: June 18, 2018
    Publication date: June 3, 2021
    Applicants: Kwansei Gakuin Educational Foundation, JNC Corporation
    Inventors: Takuji Hatakeyama, Akio TAJIMA, Akihide MIZUTANI, Daisuke BABA, Yuko YAMAGA
  • Patent number: 10938499
    Abstract: It is difficult in the elastic optical network to achieve a balance between the improvement in the frequency utilization efficiency and the increase in the probability of opening an optical path; therefore, an optical path controller according to an exemplary aspect of the present invention includes route selection means for searching for a route candidate being a candidate for a route to accommodate an optical path, and selecting a best possible route with a minimum route selection index serving as an index for route search; use rate collecting means for collecting a use rate serving as an index to indicate a usage condition of an optical frequency band in an optical fiber transmission line included in the route candidate; and route selection index judgment means for determining the route selection index based on the use rate.
    Type: Grant
    Filed: July 6, 2017
    Date of Patent: March 2, 2021
    Assignee: NEC Corporation
    Inventors: Shinsuke Fujisawa, Akio Tajima, Hitoshi Takeshita
  • Publication number: 20210058157
    Abstract: In a multi-layer network, a control load in the upper layer network increases, and the usage efficiency and the reliability of the entire network decrease; therefore, a multi-layer network system according to an exemplary aspect of the present invention includes a first network manager configured to set a logical path in a first network layer; and a second network manager configured to set a physical path corresponding to the logical path, in a second network layer, wherein the second network manager includes a network information storage configured to store physical network information including physical route information and transmission characteristic information on the second network layer, and the first network manager sets the logical path based on the physical network information.
    Type: Application
    Filed: November 6, 2020
    Publication date: February 25, 2021
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
  • Patent number: 10848245
    Abstract: In a multi-layer network, a control load in the upper layer network increases, and the usage efficiency and the reliability of the entire network decrease; therefore, a multi-layer network system according to an exemplary aspect of the present invention includes a first network manager configured to set a logical path in a first network layer; and a second network manager configured to set a physical path corresponding to the logical path, in a second network layer, wherein the second network manager includes a network information storage configured to store physical network information including physical route information and transmission characteristic information on the second network layer, and the first network manager sets the logical path based on the physical network information.
    Type: Grant
    Filed: December 15, 2015
    Date of Patent: November 24, 2020
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Patent number: 10848262
    Abstract: In an optical communication network using the wavelength division multiplexing system, the accommodation efficiency for the optical paths decreases, and it becomes difficult to use the optical communication network efficiently, if the optical frequency slots are used concentrically in a specific optical fiber; therefore, an optical path design apparatus according to an exemplary aspect of the present invention includes route candidate selection means for searching for a route of an optical path to accommodate a communication demand and selecting a plurality of route candidates; optical path candidate selection means for selecting a plurality of optical path candidates by allocating an optical frequency band required to accommodate the optical path to each of optical fibers on the plurality of route candidates; and optical path determination means for determining the optical path from among the plurality of optical path candidates based on an optical frequency band utilization rate in the optical fibers.
    Type: Grant
    Filed: September 20, 2017
    Date of Patent: November 24, 2020
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Akio Tajima
  • Publication number: 20200344170
    Abstract: A first device transmits a first random number to a second device through a first quantum channel, and receives a second random number from the second device through a second quantum channel. The first device generates a first encryption key based on the first random number and the second random number. The second device transmits the second random number to the first device through the second quantum channel, and receives the first random number from the first device through the first quantum channel. The second device generates a second encryption key based on the first random number and the second random number.
    Type: Application
    Filed: July 9, 2020
    Publication date: October 29, 2020
    Applicant: NEC Corporation
    Inventors: Takao OCHI, Ken-ichiro YOSHINO, Akio TAJIMA
  • Publication number: 20200344533
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Application
    Filed: July 9, 2020
    Publication date: October 29, 2020
    Applicant: NEC CORPORATION
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20200313765
    Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.
    Type: Application
    Filed: June 17, 2020
    Publication date: October 1, 2020
    Applicant: NEC Corporation
    Inventors: Tomoyuki HINO, Akio TAJIMA, Hitoshi TAKESHITA, Shinsuke FUJISAWA
  • Patent number: 10750259
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Grant
    Filed: June 18, 2019
    Date of Patent: August 18, 2020
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Patent number: 10735328
    Abstract: In order to achieve the dispersion of a processing load between communication devices that perform information transmission, an information communication system according to an exemplary aspect of the present invention includes a first transmission system configured to transmit information in a direction from a first communication device to a second communication device; and a second transmission system configured to transmit information in a direction opposite to the direction of the first transmission system, wherein part of transmission information is received as received information in each of the first transmission system and the second transmission system.
    Type: Grant
    Filed: August 20, 2015
    Date of Patent: August 4, 2020
    Assignee: NEC CORPORATION
    Inventors: Takao Ochi, Ken-ichiro Yoshino, Akio Tajima
  • Patent number: 10715249
    Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.
    Type: Grant
    Filed: March 18, 2016
    Date of Patent: July 14, 2020
    Assignee: NEC CORPORATION
    Inventors: Tomoyuki Hino, Akio Tajima, Hitoshi Takeshita, Shinsuke Fujisawa
  • Publication number: 20200207787
    Abstract: A polycyclic aromatic compound in which a plurality of aromatic rings are connected by a boron atom and an oxygen atom, a sulfur atom or a selenium atom and substituted by a specific aryl such as anthracene, is useful as a material for an organic device. By the polycyclic aromatic compound, an organic EL device having at least one of efficiency and device life can be provided.
    Type: Application
    Filed: December 21, 2019
    Publication date: July 2, 2020
    Applicants: Kwansei Gakuin Educational Foundation, JNC Corporation
    Inventors: Takuji Hatakeyama, Hiroyuki Imai, Yuko Yamaga, Daisuke Inoue, Akio Tajima
  • Publication number: 20200136743
    Abstract: It is difficult in the elastic optical network to achieve a balance between the improvement in the frequency utilization efficiency and the increase in the probability of opening an optical path; therefore, an optical path controller according to an exemplary aspect of the present invention includes route selection means for searching for a route candidate being a candidate for a route to accommodate an optical path, and selecting a best possible route with a minimum route selection index serving as an index for route search; use rate collecting means for collecting a use rate serving as an index to indicate a usage condition of an optical frequency band in an optical fiber transmission line included in the route candidate; and route selection index judgment means for determining the route selection index based on the use rate.
    Type: Application
    Filed: July 6, 2017
    Publication date: April 30, 2020
    Applicant: NEC Corporation
    Inventors: Shinsuke FUJISAWA, Akio TAJIMA, Hitoshi TAKESHITA
  • Publication number: 20200045388
    Abstract: Provided are an optical communication device and an optical communication system capable of preventing the costs of equipment from increasing for an optical communication network constructed including devices provided by different vendors or devices of different generations.
    Type: Application
    Filed: March 30, 2018
    Publication date: February 6, 2020
    Applicants: National Institute of Advanced Industrial Science and Technology, NEC CORPORATION
    Inventors: Kiyo ISHII, Shu NAMIKI, Shigeyuki YANAGIMACHI, Hitoshi TAKESHITA, Akio TAJIMA
  • Patent number: 10542335
    Abstract: In the elastic optical network, there has been the problem that processing steps increase that are required to re-optimize client signals to be concentrated; therefore, an optical network controller according to an exemplary aspect of the present invention includes reallocation detection means for monitoring an operation status of at least one of an optical communication channel and an optical node device that constitute an optical network, and determining, based on the operation status, whether or not to reallocate a client signal accommodated in an optical path set in the optical network; design-candidate exclusion means for designating, as a design exclusion object, at least one of the optical communication channel and the optical node device that are associated with an optical path targeted for reallocation that accommodates the client signal that the reallocation detection means has determined to reallocate; optical path design means for determining an alternative route for the optical path targeted for
    Type: Grant
    Filed: February 8, 2017
    Date of Patent: January 21, 2020
    Assignee: NEC CORPORATION
    Inventors: Shinsuke Fujisawa, Akio Tajima, Hitoshi Takeshita, Tomoyuki Hino
  • Patent number: 10447419
    Abstract: In an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid, it is difficult to improve the usage efficiency of an optical frequency band owing to the occurrence of fragmentation of the optical frequency band; therefore, an optical network controller according to an exemplary aspect of the present invention includes an optical frequency region setting means for dividing an optical frequency band used in an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid, and setting a plurality of optical frequency regions; and an optical path setting means for setting optical paths having a common attribute in at least one of the plurality of optical frequency regions.
    Type: Grant
    Filed: April 15, 2015
    Date of Patent: October 15, 2019
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Publication number: 20190312207
    Abstract: Provided is an organic electroluminescent element having optimal light emission characteristics. The above problem is solved by an organic electroluminescent element having a light emitting layer containing a compound of formula (1) or a multimer compound having a plurality of structures of formula (1), and a compound of formula (2A) or (2B) in formula (1), ring A, ring B, and ring C each represent an aryl ring or the like, X1 and X2 each represent >O or >N—R, and the R represents an aryl or the like, and in formula (2A) or (2B), X represents an aryl or the like, and Z represents a single bond, a divalent group, or the like.
    Type: Application
    Filed: January 25, 2018
    Publication date: October 10, 2019
    Applicants: Kwansei Gakuin Educational Foundation, JNC Corporation
    Inventors: Takuji HATAKEYAMA, Akio TAJIMA, Daisuke BABA, Yukihiro FUJITA, Yuko YAMAGA, Hiroyuki IMAI
  • Publication number: 20190306597
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Application
    Filed: June 18, 2019
    Publication date: October 3, 2019
    Applicant: NEC CORPORATION
    Inventors: Hitoshi TAKESHITA, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima