Abstract: A fraud detection system that converts personal identification information into an irreversible code, acquires transaction information that includes transaction terminal identification information, stores the acquired transaction information in a transaction information storage unit, and calculates a respective transaction estimation value for a future transaction for each transaction terminal and each irreversible code, on the basis of the transaction information stored in the transaction information storage unit. When new transaction information is acquired the fraud detection system calculates a degree of deviation for the new transaction information on the basis of the transaction estimation value for the irreversible code and the transaction estimation value for the transaction terminal which are in accordance with the transaction terminal identification information included in the new transaction information, and outputs alert information when the degree of deviation is large.

Abstract: A fraud detection system that converts personal identification information into an irreversible code, acquires transaction information that includes transaction terminal identification information, stores the acquired transaction information in a transaction information storage unit, and calculates a respective transaction estimation value for a future transaction for each transaction terminal and each irreversible code, on the basis of the transaction information stored in the transaction information storage unit. When new transaction information is acquired the fraud detection system calculates a degree of deviation for the new transaction information on the basis of the transaction estimation value for the irreversible code and the transaction estimation value for the transaction terminal which are in accordance with the transaction terminal identification information included in the new transaction information, and outputs alert information when the degree of deviation is large.

Abstract: Cost-reduction in an optical communication unit is achieved by using spectrum-sliced modulated broadband light for transmitting upstream signals, instead of using laser light. An optical communication system includes at least one pair of optical communication units that each has a bi-directional network interface in which physical bit rates of transmission signals and reception signals are identical, an optical transmitter, and an optical receiver, and that performs bi-directional transmissions via at least one optical fiber. One optical communication unit includes a physical bit rate down-converter that lowers the physical bit rate of transmission signals from the bi-directional network interface and outputs to the optical transmitter, and the other optical communication unit includes a physical bit rate up-converter that raises the physical bit rate of signals received by the optical receiver and outputs to the bi-directional network interface.

Abstract: Cost-reduction in an optical communication unit is achieved by using spectrum-sliced modulated broadband light for transmitting upstream signals, instead of using laser light. An optical communication system includes at least one pair of optical communication units that each has a bi-directional network interface in which physical bit rates of transmission signals and reception signals are identical, an optical transmitter, and an optical receiver, and that performs bi-directional transmissions via at least one optical fiber. One optical communication unit includes a physical bit rate down-converter that lowers the physical bit rate of transmission signals from the bi-directional network interface and outputs to the optical transmitter, and the other optical communication unit includes a physical bit rate up-converter that raises the physical bit rate of signals received by the optical receiver and outputs to the bi-directional network interface.