  We consider an online ad network problem in which an ad exchange auctions ad
slots and intermediaries called demand side platforms (DSPs) buy these ad slots
for their clients (advertisers). An intermediary represents multiple
advertisers. Different types of ad slots are auctioned by the ad exchange,
e.g., video ad, banner ad etc. We study repeated posted price auctions for
homogeneous and heterogeneous items when there is an intermediary. In a posted
price auction, the auctioneer sets a fixed reserve price. The buyer can accept
the price and win the ad slot or reject the price.
  We analyze the system from the auctioneer's perspective and show that the
optimal reserve price is dynamic for heterogeneous items. We also investigate
system from intermediary's perspective and devise algorithms for scheduling
advertisers. Often the advertisers have budget constraints and impression
constraints. We formulate a revenue optimization problem at the intermediary
and also consider the problem of scheduling advertisers with budget and
impression constraints. Finally, we present a numerical study for the single
seller and advertiser model which considers various valuation distributions
such as uniform, exponential and lognormal.
