We present the results of multi-epoch monitoring of a blazar J1159+2914, one of the targets of
a Very Long Baseline Interferometry (VLBI) monitoring program : Interferometric MOnitoring
of GAmma-ray Bright AGNs (iMOGABA), as a Korean VLBI Network (KVN) Key Science
Program (KSP). The observations were conducted simultaneously at 22, 43, 86, and 129 GHz,
during 4 years from December 2012 to December 2016. Obtained total fluxes ranged from 0.26
to 2.88 Jy at all frequencies with a mean rms noise of 26 mJy. We also used the 15 and 230 GHz
data observed by Owens Valley Radio Observatory (OVRO) and Sub-Millimeter Array (SMA),
respectively. In order to analyze the characteristics of variabilities, we estimated variability time
scale from 15 GHz data, using three different functions, such as structure function, Gaussian
function, and exponential function. Also, in order to study the multi-frequency correlations, we
compared the light curve of 15 GHz with that of 22, 43, and 86 GHz, using cross-correlation
analysis. Moreover, we estimated B-field strength using core sizes from VLBA 43 GHz data,
turnover frequencies and maximum total fluxes from KVN data, and variability time scales from
OVRO data, in order to study the variability of B-field strength nearby the radio emission region.