Hitachi, Ltd.

Hitachi Process Computer Engineering, Inc.

Yoshiaki Adachi

Minoru Koizumi

Tomoichi Ebata

Toshiichiro Sasaki

Chiho Kitahara

Hideki Tonooka

Takuji Hamada

Hiroshi Wataya

Hisao Ogawa

Hideaki Masuko

Atsushi Matsuno

Hisao Kikuchi

Kiyokazu Tamura

Tomoyuki Harada

Shinichi Hanada

Takeshi Ishizaki

Koji Suzuki

Tetsuhiko Hirata

Hiroaki Nakanishi

Junji Fukuzawa

Ken Onuki

Tamio Iizuka

Kouji Kamoshida

Koichiro Sakuraba

Masayo Nagano

Isao Terakado

Tsutomu Onuki

Kenji Matsuzaki

Keijiro Hayashi

A technique for performing message communications while assigning a space and respective time periods or time points at present, in past and in future is disclosed. A space-time object intercepts a message. Alternatively, this object per se executes the processing for immediately transmitting a message to a target object under management with relevancy thereto, for retaining the message by a future time point assigned, or for preparing and sending a message for searching logs in the past, thereby to realize the space-time communications.

Space-time communication system

A network system has a plurality of nodes being operated by their communication application programs. In the network system, each of the nodes includes a transmission rate control module for obtaining a communication attribute required for controlling a communication band from the communication application program, a band information managing table for storing the obtained communication attribute, a band information transmitting module for delivering the band information of the local node to all the other nodes connected with the network, a band information receiving module for receiving the band information delivered by the band information transmitting module of another node and storing the band information in the band information managing table. The transmission rate control module is served to obtain the current band traffic on the basis of the band information stored in the band information managing table and perform the band control.

Network system and communication band control method thereof

Occurrence of significant difference of transmission rate between communication zones can be prevented to maintain the transmission rate of overall network uniform. The radio network system includes a plurality of radio communication control units are connected with each other via radio main line, and each radio communication control unit has a communication function with at least one radio communication terminal arranged within own communication area. Each of the radio communication control units includes means for broadcasting a transmission rate restriction demand to all of other radio communication control units and all of radio communication terminals when data amount stored in a transmission and reception buffer exceeds a predetermined threshold value, and means for lowering a transmission rate when a transmission rate restriction demand is received from any other radio communication control unit within a predetermined period and for increasing the transmission rate when no transmission rate restriction demand is received from any other radio communication control unit.

Radio network system

In order to allow efficient use of bandwidth in communication paths in a surveillance system, the surveillance system has an operation unit which assigns fixed bandwidths to each of the communications taking place between camera nodes, which transfer image data at a uniform rate, and monitor nodes. A fixed bandwidth is assigned to, all communications taking place between the operation unit and sensor nodes, which generate alarm information at a non-uniform rate. If there is an increase in network traffic, bandwidth allocations, for communication between the camera nodes and the monitor nodes are reassigned so that bandwidth for these communications is reduced. The camera nodes use the bandwidth assigned to the camera nodes to transfer image data. The sensor nodes transfer alarm information using any bandwidth.

Method of controlling quality of communication among a plurality of clients over a network

Surveillance system and network system

It is designed to connect a duplicated LAN to a network terminal such as a controller having a standard serial or parallel interface, a computer having only one LAN interface, or a computer having only one communication line interface. The network interface apparatus for connecting a network terminal and a duplicated LAN comprises a device for controlling interfaces with the network terminal and the LAN transmission line of each of the duplicated LAN, a buffer, and a sending device to both, and the data from the network terminal is buffered in the buffer, and when the buffered data reaches a fixed amount, the data is sent to both LANs of the duplicated LAN. On the other hand, with respect to the data received from each LAN transmission line of the duplicated LAN, only the data which is judged as earlier arrival data is sent to the network terminal.

Network interface apparatus

There is disclosed an information processing system and method capable of coping with a wider range of subjects and intricate changes. In client server structure, time-varying database altering information received from external systems is pooled in servers and distributed to a number of distributed terminals or clients, using broadcasting communication.

Information processing system and method using time-varying database

A communication system and communication method having protocols used are to priorly process real-time data without delay. Information of a protocol header of data to be sent or received is used as priority decision information to decide whether or not the data should be priorly send- or receive-processed. The information to be priorly processed of combination of the priority decision information is registered and managed as priority data information before being stored. The data send or receive process fetches the priority decision information from the send or receive data before deciding whether or not the data are registered as the priority data information. If so, the data are send- or receive-processed prior to the data that are not registered. The communication system and communication method can priorly control the data to be processed in real time without limiting communications for each of the data treated by an application communication program even if the real-time data are mixed with non-real-time data.

Communication system and communication method

Growing community of inventors

Hitachiohta, Japan

Yoshiaki Adachi