Hitachi, Ltd.

Minoru Ogushi

Keiro Muro

Kei Suzuki

Toshiyuki Odaka

Shoji Suzuki

Motoyasu Terao

Hitoshi Kume

Satoru Hanzawa

Yoshitaka Sasago

Norikatsu Takaura

Masaharu Kinoshita

Yoshihiro Wakisaka

Norihisa Matsumoto

Takehiro Urano

A sensor-Net system includes sensor nodes which are in intermittent operation so as to save power by repeating activated state and inactivated state at a regular interval. Synchronization of time in the system is executed by aligning to the intermittent operation of the sensor nodes. A management server issues a setTime command for configuring the time to each gateway node at a specified interval. Each router node sets or corrects the time of it based on the time received from the gateway node and thereafter turns ON the time configuration flag for each sensor node in order to expand the setTime command to all of its sibling sensor nodes. The router node, upon reception of a polling, which is a command request, from the sensor node, obtains the time at that time, then uses the time to generate a setTime command to transmit to that sensor node.

Sensor-Net system and sensor node

In a sensor network system comprising a sensor terminal and a management server, the sensor terminal transmits observation data acquired using the sensor, the management server has a latest data storage manager which manages the latest observation data among observation data received from the sensor terminal, a history data storage manager which manages the history of the observation data from any time when data was received from the sensor terminal to the latest observation data, and a missing data manager which manages missing history data, and compensates the missing history data based on a predetermined rule, and when a request for such observation data is received, at least one of the latest observation data managed by the latest data storage manager, and history data wherein the missing data has been compensated and managed by the history data storage manager, is output according to the type of request.

Sensor network system for managing the latest data and history data

An overload on a communication path in a sensor network system is prevented while transferring information from a sensor node as close to real time as possible. When the transfer rate of events transferred from a boundary node (DR) toward a gateway (GW) exceeds a limit transfer rate (VL), one of nodes on the sensor node (S) side whose transmission rate meets a preset condition is identified as an excess transmission rate node. The excess transmission rate node, or a node that is not the excess transmission rate node and whose transmission rate should be reduced, is chosen as a deceleration node. A node that reduces the transmission rate of events from the deceleration node, or the transfer rate of the events, is chosen as a deceleration processing executing node. The deceleration processing executing node is instructed to execute preset processing.

Sensor network system and data processing method for sensor network

To realize a fast and highly reliable phase-change memory system of low power consumption, a semiconductor device includes: a memory device which includes a first memory array having a first area including a plurality of first memory cells and a second area including a plurality of second memory cells; a controller coupled to the memory device to issue a command to the memory device; and a condition table for storing a plurality of trial writing conditions. The controller performs trial writing in the plurality of second memory cells a plurality of times based on the plurality of trial writing conditions stored in the condition table, and determines writing conditions in the plurality of first memory cells based on a result of the trial writing. The memory device performs writing in the plurality of first memory cells based on the writing conditions instructed from the controller.

Semiconductor device

A plural-data transmission Start message is transmitted prior to transmission of plural data to an intermittent operation type wireless communications terminal, and when transmission of plural data is completed, a plural-data transmission End message is transmitted. The terminal which received the plural-data transmission Start message can change over the sleep period of the aforesaid intermittent operation to a shorter sleep period. Thereby, an improvement in the response performance in the case of plural-data delivery can be simultaneously obtained while maintaining the low power performance of a sensor node.

Sensor network system and sensor node

In a wireless communication system, a utilization of a global ID having a long bit length, which is useful for linking with an external system, is compatible with a reduction of a communication amount of a wireless terminal. The wireless terminal transmits the global ID only when the wireless terminal is initially registered, and after a local ID having a short bit length is allocated by a server to the wireless terminal, this wireless terminal uses one the local ID. While the server manages a corresponding relationship between the global ID and the local ID, the server uses the global ID in order to identify the wireless terminal in a communication made outside the system.

Wireless communication system

Disclosed is a network system that can distribute connection requests from PPPoE client terminals to specific PPPoE servers under the initiative of the PPPoE servers. In the system that realizes connection between at least one client terminal and plural servers at least by a connection start signal from the client terminal, a connection provision signal from the servers, corresponding to the connection start signal, and a connection request signal from the client terminal, corresponding to the connection provision signal; the servers have an identification information setting means, upon receiving a connection start signal from the client terminal, for setting server identification information for identifying a specific server to receive a connection request signal corresponding to the connection start signal in the connection provision signal.

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Kodaira, Japan

Minoru Ogushi