“úŽž 01/14(–Ø) 15:30- êŠ 7ŠKƒZƒ~ƒi[Žº ”­•\ŽÒ ŒÃ”¦ ªŽji¬âŒ¤PDj ƒ^ƒCƒgƒ‹ A Robust Multi-Unit Ascending-Price Auction Mechanism in Multiple Time Periods Abstract: Auctions have become enormously popular in recent years. Multi-unit ascending-price auction for spectrum allocation is a particularly successful example. However, there are some common problems in such types of auctions that are demand reduction, over declaration, untruthful due dates, and sequential decision making problems. We deal with these problems in a multi-period case where buyers may have alternative plans in different due dates. We propose a new auction mechanism, €emph{multi-period ascending-price allocation option protocol (multi-period AOP)}, which allows buyers submit alternative purchase plans. One of the important characteristics of this mechanism is that there are two types of the winner determination process: an auctioneer chooses winners (fully fulfilled) or buyers take options proposed by the auctioneer (partially fulfilled). Due to this characteristic, the proposing mechanism implements an ex-post efficient equilibrium for the multi-unit and multi-period environment.