  We present near-IR and far-UV observations of the pre-transitional (gapped)
disk in HD 169142 using NASA's Infrared Telescope Facility and Hubble Space
Telescope. The combination of our data along with existing data sets into the
broadband spectral energy distribution reveals variability of up to 45% between
~1.5-10 {\mu}m over a maximum timescale of 10 years. All observations known to
us separate into two distinct states corresponding to a high near-IR state in
the pre-2000 epoch and a low state in the post-2000 epoch, indicating activity
within the <1 AU region of the disk. Through analysis of the Pa {\beta} and Br
{\gamma} lines in our data we derive a mass accretion rate in May 2013 of (1.5
- 2.7) x 10^-9 Msun/yr. We present a theoretical modeling analysis of the disk
in HD 169142 using Monte-Carlo radiative transfer simulation software to
explore the conditions and perhaps signs of planetary formation in our
collection of 24 years of observations. We find that shifting the outer edge (r
= 0.3 AU) of the inner disk by 0.05 AU toward the star (in simulation of
accretion and/or sculpting by forming planets) successfully reproduces the
shift in NIR flux. We establish that the ~40-70 AU dark ring imaged in the NIR
by Quanz et al. (2013) and Momose et al. (2013) and at 7 mm by Osorio et al.
(2014) may be reproduced with a 30% scaled density profile throughout the
region, strengthening the link to this structure being dynamically cleared by
one or more planetary mass bodies.
