Abstract: According to an aspect of an embodiment, operations may include obtaining a first waveform profile corresponding to an optical signal received at an optical receiver via an optical link between the optical receiver and an optical transmitter. The operations may also include obtaining a second waveform profile that is an estimate of the first waveform profile. The second waveform profile may be based on one or more properties of the optical link and may be based on a complex scaling factor that accounts for rotation of the optical signal as the optical signal propagates via the optical link. In addition, the operations may include determining a power profile estimation corresponding to the optical link based on a comparison between the first waveform profile and the second waveform profile.

Abstract: A control method implemented by a computer configured to control a database that includes an aggregate item that records an aggregate value of transaction volume included in transaction data recorded in a blockchain, the control method including: obtaining a plurality of the transaction data recorded in the blockchain; specifying, for each of a plurality of second users who are transaction partners with a first user associated with the aggregate item, a transaction time with the first user on a basis of the plurality of transaction data; classifying the plurality of second users into a plurality of groups on a basis of dissimilarity of the transaction time; and generating the aggregate item for each of the groups in the database.