Discount previous time points exponentially
yt∼normal(μt,σ2),t=p+1,…,Tμt=∑i=1pϕiyt−i+xt′βϕi∼normal(0,κ1/i2),βj∼N(0,σy2σxj2κ2),j=1,…,mκ1∼gamma(1,1/0.04),κ2∼gamma(1,1/0.042),σ2∼p(σ2)