  Many theoretical expressions of dissipation along non-equilibrium processes
have been proposed. However, they have not been fully verified by experiments.
Especially for systems strongly interacting with environments the connection
between theoretical quantities and standard thermodynamic observables are not
clear. We have developed a computer simulation based on a spin-boson model,
which is in principle exact and suitable for testing the proposed theories. We
have noted that the dissipation obtained by measuring conventional
thermodynamic quantities deviates from the second law of thermodynamics
presumably due to the strong coupling. We show that additive correction to
entropy makes it more consistent with the second law. This observation appears
to be consistent with the theory based on the potential of mean force.
