One embodiment disclosed relates to a Wien filter for a charged-particle beam apparatus. The system and method exploits a wavelength-locked loop servo-control circuit and methodology that enables real time adjustment of optical signals in accordance with attenuation characteristics of an optical transmission channel. The processing platform may be further configured to generate at least one user satisfaction score for a plurality of users of the communication services given specified values of the identified metrics for only a subset of those users. For example, the second financial account may be the financial account of an insurance company or other reimbursing party. A transmitter transmits the trading strategy to an order slicer.