Nec Corporation

Toa Corporation

Etani Electronics Co., Ltd.

Nec Engineering, Ltd.

Koichi Tsuchiya

Daisuke Higashihara

Shokichiro Hino

Tomohiko Endo

Youichi Hidaka

Masanori Takashima

Takashi Yokota

Tetsu Izawa

Tsugio Okamoto

Masashi Hayashi

Shihomi Sato

Minaxay Philavong

Yutaka Takekoshi

A tunnel endpoint device includes a control unit configured to establish a communication tunnel with a tunnel endpoint device as a communication peer and an interface configured to access a storage device including communication state information about a tunnel communication. The control unit is configured to be adapted to take over state information about a tunnel communication of another tunnel endpoint device via the storage device when receiving an externally supplied switching instruction.

Tunnel endpoint device, communication device, communication system, communication method, and program

A switching process includes an SRAM/CAM storing registration data including a forwarding database used for packet-forwarding and a DRAM storing packet data. The registration data including the forwarding database of the SRAM/CAM for packet-forwarding is stored into the DRAM as a copy of the registration data, and the registration data of the DRAM is used to refresh the registration data of the SRAM/CAM for a predetermined time interval. A data error in the SRAM/CAM caused by a soft-error is rewritten to normal data by periodical refreshing so that data is guaranteed with relatively low cost and the reliability of the network apparatus is improved.

Network apparatus, control method thereof, control program and packet network system

In a switching node, high-speed and advanced service protocol processing function is achieved by utilizing an external control server without affecting performance of conventional service protocol processing. Specifically, a forwarding engine has PCI express and an LAN interface. Depending on a type of an input packet, destination of the packet is switched to the PCI express side for conventional network service and to the LAN interface side for extended network service that cooperates with the external control server. A CPU having the PCI express and the LAN interface is provided ahead of the LAN interface. The CPU performs communication of service inquiry with the external control server at high speed via the LAN interface. After response from the control server is obtained, setting of the forwarding engine is performed through the PCI express.

Communication control system, switching node, communication control method and communication control program including PCI express switch and LAN interface

Resonant frequencies fand fdetected in a resonant space are determined as center frequencies of a dip. Based on measurement values at a speaker and a microphone in the resonant space, a basic amplitude frequency characteristic Ca and a target amplitude frequency characteristic Cd are found. A smoothness degree on a frequency axis is larger in the target amplitude frequency characteristic Cd than the basic amplitude frequency characteristic Ca. A damping level and quality factor of the dip are determined based on a difference between the basic amplitude frequency characteristic Ca and the target amplitude frequency characteristic Cd in the center frequencies fand fof the dip and frequencies near the center frequencies.

Dip filter frequency characteristic decision method

A devicefor measuring a propagation time of a sound wave comprises a sound source meansand a calculation means. The sound source meansoutputs a time stretched pulse as a sound source signal input to a speaker. The calculation meanscalculates a cross-correlation function of the time stretched pulse and the sound signal which is output from the speakerand is received in a microphone. Based on the cross-correlation function, the propagation time of the sound wave between the speakerand the microphoneis found.

Method and device for measuring sound wave propagation time between loudspeaker and microphone

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Tokyo, Japan

Koichi Tsuchiya