Nec Corporation

Satoru Yamano

Shohei Mitani

Takashi Konashi

Hiroyuki Sato

Hideaki Tani

Jun Nishioka

Masanobu Arai

Toshiki Watanabe

Yumi Hirano

Yoshinobu Oshima

Huanxu Pan

Yasukazu Murata

Takahiro Ookuma

Syuji Sakata

An estimation apparatusincludes: a correlation index estimation unitconfigured to receive a variable output by a componentas an input, and estimate correlation index information indicating a range that a value of the variable and a correlation can take after a predetermined time, at a normal time; an abnormality degree calculation unitconfigured to calculate an abnormality degree using the correlation index information; and a causal effect estimation unitconfigured to estimate a causal effect expressing an index indicating that an abnormality propagates to a variable output by the component

Estimation apparatus, estimation method, and computer-readable storage medium

A surveillance device according to the present invention includes: a memory; and at least one processor coupled to the memory. The processor performs operations. The operations includes: calculating, based on a value of a parameter that is contained in a received data frame and represents a state of an apparatus, a change in the state of the apparatus; and determining whether the change is included in an allowable range determined in accordance with the state of the apparatus before the change.

Surveillance device, learning device, surveillance method and storage medium

An estimation apparatusincludes: a normal index estimation unitconfigured to estimate, using a second variable output by a second componentthat influences a first variable output by a first component, an index A indicating that the first variable is achieved at a normal time; and an abnormality propagation information estimation unitconfigured to estimate abnormality propagation information expressing an index indicating that an abnormality propagates to a third variable output by a third componentinfluenced by the first component, by changing the first variable.

An extraction device includes: at least one memory configured to store instructions; and at least one processor configured to execute the instructions to: sort each set of frames that have the same identifier associated with a node, into frames maintaining a cycle and frames out of the cycle; and extract, as an event rule, a feature of a bit change in a data field related to an event occurrence, from the frames that have the same identifier and are out of the cycle.

Extraction device, extraction method, recording medium, and detection device

An extraction apparatus can obtain a first alert and a second alert that are generated, when an anomaly occurs in a control system, in order to provide notification of the anomaly. The extraction apparatus includes: a classification unit configured to generate association information associating the first alert with the second alert; a learning unit configured to learn a generation pattern of the second alert when the anomaly occurs due to a cause other than a cyber-attack based on the association information generated by the classification unit and a generation pattern of the first alert when the anomaly occurs due to a cause other than a cyber-attack; and an extraction unit configured to extract, from among the second alerts, the second alert generated due to a cyber-attack based on the generation pattern of the second alert that is learned by the learning unit and output the extracted second alert.

Extraction apparatus, extraction method, computer readable medium

In order to settle a problem of suppressing degradation of a throughput of a communication system, a communication device is provided with a reception means which receives and accumulates a first datum which a first device transmits addressing a second device and a second datum which the second device transmits, a transmission means which transmits the first datum to the second device, a quality index acquisition means which acquires a first index which is a quality of communication between the first device and the second device and a second index which is a quality of communication between the communication device and the second device, and a judgment means which forces to transmit the accumulated first datum to the second device using the transmission means in the case of judging that the second index is better than the first index and a reception condition of the second datum shows that the second device does not receive normally the first datum.

Providing suppressing degradation of throughput of communication device, recording medium for control program of communication device, communication system and communication method

A path control system according to the present invention includes a network including a communication device () that communicates via a radio link that uses adaptive modulation, and a path control device () predicting a future modulation mode for the radio link and setting a communication path for the network based on a predicted mode that is the predicted modulation mode.

Path control system, path control device, path control method, and program

There is provided a packet joining method, program, and apparatus with an increased wireless utilization efficiency and a reduced packet delay. The packet joining method includes a step of performing Neighbor Discovery within a range reachable in one hop to detect neighboring audio terminals which are connectable over short-range radio and acquiring call information including audio session information such as whether the detected audio terminals are busy with respective calls and packetization period information and wireless transmission rate information, a step of selecting one as a joining destination from the list of detected connectable audio terminals on the basis of the call information by the criteria that occupancy time of wireless transmission becomes short and that a packet delay at the time of joining becomes small, a step of requesting packet joining of the selected audio terminal as the joining destination, and a step in which an audio terminal as a joining source starts a voice call upon receipt of a positive response from the audio terminal as the joining destination in response to the request for joining.

Packet joining method, program, and apparatus

A radio communication method, a radio communication system and a wireless terminal by which low power consumption and the flexibility of a network can be realized. A base station and wireless terminals change an intermittent receive period and the preamble length of data on the basis of characteristics of the multihop radio network to carry out the intermittent receiving of data. Thus, a wireless terminal relaying data can receive the data reliably and a useless boot-up of a receiving part and standby time can be largely reduced to achieve low power consumption.

Radio communication method, radio communication system and wireless terminal

The present invention is to provide a wireless communication system that is capable of preventing occurrence of radio interference caused by radio wave used by a radio wave generator without requiring any improvement of existing wireless devices. The wireless communication system of the present invention includes: a radio wave generator () that uses at least a radio wave in a frequency band that overlaps a frequency band used by a wireless standard; and wireless devices (AP, STA) each of which uses a radio wave conforming to the wireless standard. The radio wave generator () transmits a dummy frame conforming to the wireless standard to the wireless devices near the radio wave generator () before generating the radio wave in the same frequency band as the frequency band used by the wireless standard. When the wireless devices (AP, STA) receive the dummy frame, the wireless devices (AP, STA) control themselves to stop using the radio wave in the frequency band that has radio interference caused by the radio wave generated from the radio wave generator ().

Radio wave generator, wireless communication system, radio interference prevention control method, and radio interference prevention control program

A traffic performance in a tree type multi-hop wireless network of a CSMA/CA method is evaluated easily and highly precisely. A traffic performance evaluation system in the multi-hop wireless network includes: a performance index estimation unit regarding the multi-hop wireless network as a combination of a plurality of single-hop wireless networks and estimating a traffic performance index around each node of the network; and a performance index determination unit determining a traffic performance index of the whole multi-hop wireless network based on an estimation result of all the nodes by the performance index estimation unit.

Traffic performance evaluation system in wireless network and method thereof

A gateway device includes PDTN line terminating portion, audio data processing portion, header processing portion, packet network line terminating portionand gateway control processor. Header processing portionreceives an RTP packet with session number from audio data processing portionand outputs an IP packet attached with UDP/IP header information to packet network line terminating portion. Header processing portionreceives an IP packet from packet network line terminating portionand checks UDP/IP header thereof When the IP packet is an audio packet, header processing portiondeletes the UDP/IP header, attaches a session number thereto and outputs an RTP packet with session number to audio data processing portionand, when the IP packet is an audio packet, header processing portiontransfers it directly to audio data processing portionto send the audio data to the PSTN through PSTN line terminating portion

Audio gateway device

A cell flow synchronization establishing system of an ATM access system, capable of establishing synchronization of cell flow between a mobile station and base stations at the time of hand-off process, is provided. First buffer control unit is provided in the ATM switching station, and second buffer control unit is provided in the mobile station. The first buffer control unit reproduces cell stream to be transmitted by guaranteeing orderness of ATM cell between the first buffer control unit and the second buffer control unit and buffer clear processing is carried out based on predetermined synchronization establishment processing sequence before and after occurrence of handoff.

Growing community of inventors

Tokyo, Japan

Satoru Yamano