Abstract: According to one embodiment, an anomaly detection apparatus includes a processing circuit. The processing circuit is configured to: acquire measured values from sensors installed in a system, a first function, a first threshold, and a second function to output a second threshold; generate the predicted values based on the measured value and the first function; detect that a deviation between the measured values and the predicted values exceeds the first threshold; calculate the feature quantities based on the measured values; and determine whether a number of consecutive times is equal to or larger than the second threshold to detect an anomaly or a sign of the anomaly.

Abstract: A communication system includes a station-side terminal apparatus and multiple subscriber-side terminal apparatuses connected to the station-side terminal apparatus. The station-side terminal apparatus is configured to, in response to receipt of a packet from a subscriber-side terminal apparatus, a packet indicating whether data distribution is required, identify the subscriber-side terminal apparatus that has transmitted the packet, and transmit a packet indicating an address for which whether the transfer of distribution data is required is designated to the subscriber-side terminal apparatus based on whether data distribution is required.

Abstract: A method of communicating through a passive optical network (PON) that improves the efficiency of the network with low cost child apparatuses having only simple functions. A parent apparatus provides the child apparatuses with a multi-frame standard signal, and a child apparatus transfers asynchronous information as a frame of variable length, as it is, at a time delayed from the multi-frame standard signal by a time period designated by the parent apparatus. Since the asynchronous information does not need to be divided into pieces to which a frame header is attached, the efficiency of the uplink channel is increased.

Abstract: A communication system includes a station-side terminal apparatus and multiple subscriber-side terminal apparatuses connected to the station-side terminal apparatus. The station-side terminal apparatus is configured to, in response to receipt of a packet from a subscriber-side terminal apparatus, a packet indicating whether data distribution is required, identify the subscriber-side terminal apparatus that has transmitted the packet, and transmit a packet indicating an address for which whether the transfer of distribution data is required is designated to the subscriber-side terminal apparatus based on whether data distribution is required.

Abstract: An optical access system that sends packets in a given time slot more efficiently without wasting bandwidth. The uplink channel from slave devices to a master device is divided into time slots. The sending slave device reads out upstream packets from its send packet buffer when an assigned time slot comes. If the maximum frame size is reached in the middle of a packet, the slave device suspends further reading until a next assigned time slot comes. The packets are sent to the master device, each being set off by a start and end delimiters. Detection of a start delimiter causes the master device to begin writing each received data word into a receive packet buffer, which is terminated by the end delimiter of that packet. Received packets are retrieved from their memory locations specified by a read address that includes the sender's slave device number.

Abstract: A method of communicating through a passive optical network (PON) that improves the efficiency of the network with low cost child apparatuses having only simple functions. A parent apparatus provides the child apparatuses with a multi-frame standard signal, and a child apparatus transfers asynchronous information as a frame of variable length, as it is, at a time delayed from the multi-frame standard signal by a time period designated by the parent apparatus. Since the asynchronous information does not need to be divided into pieces to which a frame header is attached, the efficiency of the uplink channel is increased.

Abstract: A plurality of cell switches that operate at a basic switching rate are provided, and a unit including (FIFO buffers) for queuing cells from the transmission line are provided in correspondence with respective ones of the cell switches. Cells from the transmission line are demultiplexed and written to the prescribed FIFO buffer by a cell demultiplexer, cells are read out of each FIFO buffer at the basic switching rate and entered into the corresponding cell switch, and cells switched by each of the cell switches are multiplexed and sent to a transmission line by a multiplexer.

Abstract: A plurality of modules, each connected to communication lines, are interconnected by a logically separated interprocessor communication bus for transferring header information and control information and a frame transfer bus for transferring data. When each module receives data from a line, the module generates a header containing header information from the received data, stores the header and user data in respective queue-type data storage sections, and transmits the header on the interprocessor communication bus; when one of the other modules detects its own identification from the header on the bus, the module sends a data send request to the transmitting module which in response reads the data from the data storage and outputs it on the frame transfer bus for transmission to the requesting module.

Abstract: In a network, a route which can be uniquely identified is constructed by selecting an arbitrary packet-switching node and an arbitrary transmission line in an arbitrary order from the network. A route memory unit stores data indicating which route is involved in which transmission line within the network. A congested state detecting unit detects a congested state of a transmission line accommodated within its own node. The detected congested state is transmitted to another node by a congested state informing unit as congested state information. A route identifying unit receives the congested state information from the other node and retrieves a route within a corresponding transmission line from the route memory unit to thereby identify the route accommodated within its node. A route control unit carries out control of the congested state of the identified route on the basis of the received congested state information.

Abstract: A packet switching system having a matrix switch including input packet transfer buses and output packet transfer buses. Transfer buffers or gates are provided at cross points of the input and output packet transfer buses. An input packet is supplied to the matrix switch through a transfer control circuit, and an output packet from the matrix switch is output through the transfer control circuit. The input packet is permitted to be applied to the matrix switch so that each of the output packet transfer buses has only one packet during one packet transfer cycle.