  The configuration and evolution of the magnetic field in star-forming cores
are investigated in order to directly compare simulations and observations. We
prepare four different initial clouds having different magnetic field strengths
and rotation rates, in which magnetic field lines are aligned/misaligned with
the rotation axis. First, we calculate the evolution of such clouds from the
prestellar stage until long after protostar formation. Then, we calculate the
polarization of thermal dust emission expected from the simulation data. We
create polarization maps with arbitrary viewing angles and compare them with
observations. Using this procedure, we confirmed that the polarization
distribution projected on the celestial plane strongly depends on the viewing
angle of the cloud. Thus, by comparing the observations with the polarization
map predicted by the simulations, we can roughly determine the angle between
the direction of the global magnetic field and the line of sight. The
configuration of the polarization vectors also depends on the viewing angle. We
find that an hourglass configuration of magnetic field lines is not always
realized in a collapsing cloud when the global magnetic field is misaligned
with the cloud rotation axis. Depending on the viewing angle, an S-shaped
configuration of the magnetic field (or the polarization vectors) appears early
in the protostellar accretion phase. This indicates that not only the magnetic
field but also the cloud rotation affects the dynamical evolution of such a
cloud. In addition, by comparing the simulated polarization with actual
observations, we can estimate properties of the host cloud such as the
evolutionary stage, magnetic field strength, and rotation rate.
