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).

  • Publication number: 20160212511
    Abstract: In an optical network by a highly dense wavelength division multiplexing system using a flexible frequency grid, it is difficult to improve the optical bandwidth utilization efficiency in the optical network as a whole with improving the fault tolerance, therefore, an optical network controller according to an exemplary aspect of the present invention includes an optical path setting means for selecting a plurality of optical node pairs composed of two optical nodes from among a plurality of optical nodes composing the optical network by a highly dense wavelength division multiplexing system using a flexible frequency grid, and setting, between each of the plurality of optical node pairs, a plurality of optical paths including a first optical path and a second optical path each of which links the optical node pair through various routes; and an optical band setting means for setting respective optical bands based on optical path length and transmission capacity so that an amount of optical bandwidths of the f
    Type: Application
    Filed: September 1, 2014
    Publication date: July 21, 2016
    Inventors: Hitoshi TAKESHITA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20150291737
    Abstract: The invention relates to a thermosetting resin composition containing (A) to (D) below. (A) A thermosetting resin containing an SiH group and an alkenyl group, wherein the thermosetting resin is a reaction product between silsesquioxane having the SiH group and organopolysiloxane having two alkenyl groups; (B) a linear organopolysiloxane compound having an SiH group only at one terminal; (C) a silane coupling agent having an epoxy group; and (D) a Pt catalyst.
    Type: Application
    Filed: October 11, 2013
    Publication date: October 15, 2015
    Inventors: Akio Tajima, Takashi Matsuo, Kiichi Kawabata, Koichi Ayama
  • Patent number: 9160529
    Abstract: A user request can be reflected in the degree of security of an updated key in quantum key distribution. A sender and a receiver are connected through optical fiber. A quantum transmitter in the sender and a quantum receiver in the receiver carry out basis reconciliation and error correction through a quantum channel, based on a source of a key sent from the quantum transmitter and on a raw key received by the quantum receiver. Under the control of security control sections in the sender and receiver, the amount of information having the possibility of being intercepted, which is determined in accordance with a degree of security requested by a user, is removed from the key information after error correction, whereby a final cryptographic key is generated. Secret communication is performed between encryption/decryption sections in the sender and receiver by using the cryptographic key thus updated.
    Type: Grant
    Filed: August 18, 2006
    Date of Patent: October 13, 2015
    Assignee: NEC CORPORATION
    Inventors: Akio Tajima, Akihiro Tanaka, Wakako Maeda, Seigo Takahashi
  • Publication number: 20150289036
    Abstract: It is difficult to increase the number of inputs and outputs of an optical switch supporting CDC functions, therefore, an optical switch according to an exemplary aspect of the present invention includes a unit optical switch inputting n optical signals and outputting n optical signals; an optical splitter inputting a single optical signal, splitting the single optical signal into k optical signals, and outputting the k optical signals; and an optical selector inputting m optical signals and outputting a single optical signal, wherein the optical splitter includes m×n pieces, the unit optical switch includes m×k pieces, the optical selector includes n×k pieces, (k×(m×n)) outputs of the optical splitter correspond to (n×(m×k)) inputs of the unit optical switch, (n×(m×k)) outputs of the unit optical switch correspond to (m×(n×k)) inputs of the optical selector, and (n×m) optical signals inputted into the optical splitter are output through the (m×k) unit optical switch from the optical selector as (n×k) optical
    Type: Application
    Filed: November 12, 2013
    Publication date: October 8, 2015
    Inventors: Hitoshi Takeshita, Ryuichi Ikematsu, Akio Tajima
  • Patent number: 9115243
    Abstract: A solution is a liquid organosilicon compound represented by general formula (1) as described below: wherein, X is each independently a group represented by formula (I), formula (II) or formula (III) as described below, and when the number of the group represented by formula (I) per one molecule of the liquid organosilicon compound represented by general formula (1) is defined as a, the number of the group represented by formula (II) per one molecule thereof is defined as b, and the number of the group represented by formula (III) per one molecule thereof is defined as c, 0?a?3.5, 0?b?3.
    Type: Grant
    Filed: November 6, 2014
    Date of Patent: August 25, 2015
    Assignee: JNC CORPORATION
    Inventors: Kiichi Kawabata, Akio Tajima, Takashi Matsuo, Kiyoshi Sakai, Koichi Ayama
  • Patent number: 9112677
    Abstract: A communication device and a cryptographic key creation method are provided that enable efficient creation of cryptographic keys of which different error rates are required. A communication device (11) that performs communication with another communication device (12) through a transmission link includes a cryptographic key sharing section (1103) that share a first cryptographic key with the other communication device, an error rate control section (1115, 1105-1108) that creates second cryptographic keys with error rates according to purposes of use of the cryptographic keys from the first cryptographic key, and an accumulation section (111, 1112) that separately accumulates the plurality of second cryptographic keys with the different error rates.
    Type: Grant
    Filed: April 6, 2012
    Date of Patent: August 18, 2015
    Assignee: NEC CORPORATION
    Inventors: Akihiro Tanaka, Akio Tajima
  • Publication number: 20150180579
    Abstract: [Problem to be Solved] There is provided an optical transmission device in wavelength-division-multiplexing-based optical communications that has both of improved reliability because of provision of backup optical transceiving unit and power saving capability because of appropriate control. [Solution] An optical transmission device is configured with optical switch means 40, a plurality of optical transceiving means 41 and control means 42. The optical switch means 40 outputs an input optical signal to a given path. Each optical transceiving means 41 receives an optical signal from the optical switch means 40 and transmits an optical signal to the optical switch means 40. The control means 42 performs various kinds of control.
    Type: Application
    Filed: July 24, 2013
    Publication date: June 25, 2015
    Applicant: NEC Corporation
    Inventors: Akio Tajima, Kenji Mizutani
  • Patent number: 8987358
    Abstract: The invention provides an adhesion-imparting agent having heat-resistant transparency and a high refractive index best suited for an addition hardening type composition including a reaction product of silsesquioxane and organopolysiloxane. The invention relates to a compound obtained by allowing a hydrosilylation addition reaction of (A), (B), and when necessary, (C) as described below, and a compound including an organopolysiloxane or silsesquioxane skeleton including as an essential component an isocyanuric ring skeleton and an epoxy group, and having an SiH group residue: (A) a compound including an organopolysiloxane or silsesquioxane skeleton and having three or more SiH groups in one molecule; (B) an epoxy derivative having one aliphatic unsaturated group in one molecule; and (C) organopolysiloxane having two alkenyl groups in one molecule, and having a number average molecular weight of 100 to 500,000, or an isocyanurate compound having two alkenyl groups in one molecule.
    Type: Grant
    Filed: June 28, 2012
    Date of Patent: March 24, 2015
    Assignee: JNC Corporation
    Inventors: Kiichi Kawabata, Akio Tajima, Takashi Matsuo, Yoshiko Watanabe, Koichi Ayama
  • Publication number: 20150071303
    Abstract: A communication device and a power saving method in a data transmission system are provided that can achieve the prevention of element deterioration occurring when a check signal is transmitted during sleep, as well as reductions of transmission noise and power consumption. The communication device, which is connected to another communication device through transmission/reception links corresponding to multiple channels, respectively, includes communication sections (13-1 to 13-N, 141 to 14-N) corresponding to the multiple channels, respectively, and a control section (10) that interrupts transmission outputs of the communication element when there is no data for transmission, and sequentially changes, among the multiple channels, a channel that transmits a check signal for checking a link state during a period in which the transmission outputs are kept interrupted.
    Type: Application
    Filed: March 21, 2013
    Publication date: March 12, 2015
    Inventor: Akio Tajima
  • Publication number: 20150065643
    Abstract: A solution is a liquid organosilicon compound represented by general formula (1) as described below: wherein, X is each independently a group represented by formula (I), formula (II) or formula (III) as described below, and when the number of the group represented by formula (I) per one molecule of the liquid organosilicon compound represented by general formula (1) is defined as a, the number of the group represented by formula (II) per one molecule thereof is defined as b, and the number of the group represented by formula (III) per one molecule thereof is defined as c, 0?a?3.5, 0?b?3.
    Type: Application
    Filed: November 6, 2014
    Publication date: March 5, 2015
    Inventors: KIICHI KAWABATA, AKIO TAJIMA, TAKASHI MATSUO, KIYOSHI SAKAI, KOICHI AYAMA
  • Patent number: 8952108
    Abstract: A liquid organosilicon compound comprising a structural unit represented by the following formula (1-a) and a structural unit represented by the following formula (1-b): In the above formula (1-a), R1 each independently is a group selected from an alkyl having 1 to 4 carbon atoms, cyclopentyl and cyclohexyl and in the above formula (1-b), R2 and R3 each independently are a group selected from an alkyl having 1 to 4 carbon atoms, cyclopentyl and cyclohexyl, and n is an integer of 2 to 50. When a mole fraction of the structural unit represented by the formula (1-a) in the liquid organosilicon compound is ? and a mole fraction of the structural unit represented by the formula (1-b) in the liquid organosilicon compound is ?, the ratio of ? and n×? (?:n×?) meets 1:3 to 1:100.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: February 10, 2015
    Assignee: JNC Corporation
    Inventors: Daisuke Inoki, Kiichi Kawabata, Akio Tajima, Takashi Matsuo
  • Patent number: 8946357
    Abstract: A solution is a liquid organosilicon compound represented by general formula (1) as described below: wherein, X is each independently a group represented by formula (I), formula (II) or formula (III) as described below, and when the number of the group represented by formula (I) per one molecule of the liquid organosilicon compound represented by general formula (1) is defined as a, the number of the group represented by formula (II) per one molecule thereof is defined as b, and the number of the group represented by formula (III) per one molecule thereof is defined as c, 0?a?3.5, 0?b?3.
    Type: Grant
    Filed: May 18, 2011
    Date of Patent: February 3, 2015
    Assignee: JNC Corporation
    Inventors: Kiichi Kawabata, Akio Tajima, Takashi Matsuo, Kiyoshi Sakai, Koichi Ayama
  • Patent number: 8949300
    Abstract: A random number quality control circuit capable of fast control of the level of random number quality is present. When a “0” output section and a “1” output section generate random numbers by individually receiving a random number signal, a random number quality monitor monitors an unbalance between the numbers of “0”s and “1”s. If a deviation from a desired ratio is found, a drive controller controls the reception characteristics of the “0” output section and “1” output section individually so that the deviation will be compensated for. The amount of information intercepted between a sender and a receiver can be reduced by maintaining the mark ratio of shared random numbers at 50%.
    Type: Grant
    Filed: January 10, 2007
    Date of Patent: February 3, 2015
    Assignee: NEC Corporation
    Inventors: Akihiro Tanaka, Akio Tajima, Seigo Takahashi, Wakako Maeda
  • Patent number: 8929734
    Abstract: In order to realize a multiplexer/demultiplexer in which utilization efficiency of a frequency is high, wavelength characteristics of a transmission band is flat, the cost is low, the size is small, and a wavelength and a band are variable, the multiplexer/demultiplexer includes: first light branching means for branching inputted light into plurality of pieces of light and outputting the branched pieces of light; a plurality of light wavelength separating means for separating and outputting light outputted from the first light branching means for each of predetermined frequency bands; and an optical coupling means for making outputs having frequency bands different from each other among outputs from the light wavelength separating means gather and be outputted.
    Type: Grant
    Filed: June 15, 2011
    Date of Patent: January 6, 2015
    Assignee: NEC Corporation
    Inventors: Kenji Mizutani, Akio Tajima, Masahiro Sakauchi, Tomoyuki Hino, Masahiro Hayashitani, Hiroyuki Takagi
  • Patent number: 8833511
    Abstract: In a conventional hard material insulator, reproduced sound can be tuned with use of characteristics of the material; however, various types of acoustic materials have specific high frequency characteristics, and thus their acoustic effects lack versatility, require compatible audio devices, and change with environment, musical genre, etc. To address this, a wind-bell member (resonant member) is arranged in parallel with a main propagation path of vibration transferred from an audio device to an insulator. Accordingly, a vibration system of a wind-bell having a tone determined by many factors such as a fundamental tone, harmonic tones, lingering sound, and fluctuation assists (enhances) high frequency vibration propagated from the audio device. As a result, due to the above assist action that is different in principle from a conventional type, acoustic characteristics such as a sense of localization, resolution, and a sense of transparency and scale a sound image can be dramatically improved.
    Type: Grant
    Filed: July 29, 2011
    Date of Patent: September 16, 2014
    Assignee: Tokkyokiki Corporation
    Inventors: Teruo Maruyama, Kozo Okamoto, Satoki Yamaguchi, Akio Tajima
  • Publication number: 20140148536
    Abstract: The invention provides an adhesion-imparting agent having heat-resistant transparency and a high refractive index best suited for an addition hardening type composition including a reaction product of silsesquioxane and organopolysiloxane. The invention relates to a compound obtained by allowing a hydrosilylation addition reaction of (A), (B), and when necessary, (C) as described below, and a compound including an organopolysiloxane or silsesquioxane skeleton including as an essential component an isocyanuric ring skeleton and an epoxy group, and having an SiH group residue: (A) a compound including an organopolysiloxane or silsesquioxane skeleton and having three or more SiH groups in one molecule; (B) an epoxy derivative having one aliphatic unsaturated group in one molecule; and (C) organopolysiloxane having two alkenyl groups in one molecule, and having a number average molecular weight of 100 to 500,000, or an isocyanurate compound having two alkenyl groups in one molecule.
    Type: Application
    Filed: June 28, 2012
    Publication date: May 29, 2014
    Applicant: JNC CORPORATION
    Inventors: Kiichi Kawabata, Akio Tajima, Takashi Matsuo, Yoshiko Watanabe, Koichi Ayama
  • Publication number: 20140133800
    Abstract: An optical switch control device includes a driving control unit (106) controlling a plurality of optical switches (105) which are respectively provided between a plurality of input ports (102) and a plurality of output ports (103) and respectively turn on and off the transmission of light from the plurality of input ports (102) to the plurality of output ports (103), wherein the driving control unit (106) performs a control operation of changing the optical switch (105) from an off state to an on state prior to a control operation of changing the optical switch (105) from the on state to the off state.
    Type: Application
    Filed: June 7, 2012
    Publication date: May 15, 2014
    Applicant: NEC CORPORATION
    Inventors: Tomoyuki Hino, Masahiro Sakauchi, Akio Tajima
  • Patent number: 8718485
    Abstract: In a quantum cryptographic transmitter (11), a phase modulator (1103, 1104) and an LN intensity modulator (1105) apply optical phase modulation and light intensity modulation to an optical signal based on desired data to generate a desired optical signal to be transmitted to a quantum cryptographic receiver (13). Based on the number of photons detected from the desired optical signal, a bias control circuit (1108) controls an operating point in light intensity modulation of the LN intensity modulator (1105).
    Type: Grant
    Filed: July 9, 2008
    Date of Patent: May 6, 2014
    Assignee: NEC Corporation
    Inventors: Akihiro Tanaka, Akio Tajima, Seigo Takahashi, Wakako Maeda
  • Publication number: 20140037087
    Abstract: A communication device and a cryptographic key creation method are provided that enable efficient creation of cryptographic keys of which different error rates are required. A communication device (11) that performs communication with another communication device (12) through a transmission link includes a cryptographic key sharing section (1103) that share a first cryptographic key with the other communication device, an error rate control section (1115, 1105-1108) that creates second cryptographic keys with error rates according to purposes of use of the cryptographic keys from the first cryptographic key, and an accumulation section (111, 1112) that separately accumulates the plurality of second cryptographic keys with the different error rates.
    Type: Application
    Filed: April 6, 2012
    Publication date: February 6, 2014
    Applicant: NEC CORPORATION
    Inventors: Akiro Tanaka, Akio Tajima
  • Patent number: 8638942
    Abstract: A method for managing shared random numbers in a secret communication network including at least one center node and a plurality of remote nodes connected to the center node, includes: sharing random number sequences between the center node and respective ones of the plurality of remote nodes; when performing random numbers sharing between a first remote node storing a first random number sequence shared with the center node and a second remote node storing a second random number sequence shared with the center node, distributing a part of the second random number sequence from the center node to the first remote node; and sharing the part of the second random number sequence between the first remote node and the second remote node.
    Type: Grant
    Filed: April 21, 2009
    Date of Patent: January 28, 2014
    Assignee: NEC Corporation
    Inventors: Wakako Maeda, Akio Tajima, Seigo Takahashi, Akihiro Tanaka