Abstract: A virtual LAN system forms a virtual group which is based on elements having physical attribute or logical attribute and constituting a virtual LAN, sets a client address and priority of the virtual group in a virtual group registration table, and allocates unicast and broadcast traffic bands in group units.

Abstract: A switching device for LAN is provided for switching packets in ETHERNET. The switching device includes an arrangement for storing the packet received at one of a plurality of receiving ports respectively connected to ETHERNET segments in a receiving buffer commonly used by the whole of the device, by means of a storage device of the receiving buffer. A transmitting destination port for the packet is determined through the use of an address filter device also common for the whole device. A transmitting buffer includes a storage device which receives the packet from the receiving buffer. Then, the packet is transferred from the storage device of the transmitting buffer to one of a plurality of transmitting ports corresponding to the determined address.

Abstract: A network administration system includes a network of a plurality of cascade connected repeaters for functional terminal units, and an administrative terminal connected through a transmission path to the network for administrating the network of the repeaters and terminal units, the system being arranged for transmitting from said administrative terminal a command packet to the network for recognition of connecting arrangement between the respective repeaters and terminal units, returning from the network a return packet to the administrative terminal in response to the command packet, and analyzing in the administrative terminal the return packet for automatically recognizing the connecting arrangement in the cascade connection of the repeaters and terminal units included within the network and precisely locating one of the repeaters and one of its connecting ports to which one of the terminal units involving a trouble is connected.

Abstract: A picture encoding system which performs a prediction of picture element values within a block having a plurality of picture elements into which an original picture is divided, a discrete sine transform with respect to prediction error signals for obtaining a transform coefficient, a quantization of the transform coefficient for encoding quantized indexes, an inverse quantization of the quantized indexes for reproduction of the transform coefficient, an inverse discrete sine transform of the reproduced coefficient to reproduce the prediction error signal, and an addition thereto of the predicted picture element value for reproducing the picture element values within the block to employ them in predicting a next stage block to be encoded, whereby the block can be minimized in size while simplifying required transform operation.

Abstract: An optically scanning displacement sensor is arranged to compute by means of a triangulation an inverse function from a first measured distance signal proportional to output position signals from a position detecting means which receiving reflected light from an object to be detected, and the first measured distance signal is multiplied at a linearity correcting means by a signal of a sum of the inverse function and a constant so as to compute a second measured distance signal, whereby a two-dimensional position detection can be realized with the least required memory capacity and the minimum adjusting process.

Abstract: An abnormality supervising system compares an input picture with a previously stored reference picture having no abnormality, provides a compared picture signal to an abnormality discrimination means having preliminarily stored information for abnormality discrimination, and, upon presence of an abnormality, operates an output means for informing operation, whereby the abnormality discrimination means can effectively attain the abnormality discrimination on the basis of the preliminarily stored information, in a highly reliable manner.