This is largely the result of ATTac-2000 not yet being imbued with its adaptive timing of bidding modes  During the preliminary round  ATTac-2000 shifted from passive to active se conds left in the game instance  While seconds is usually plenty bidding mode with of time to allow for at least iterations through ATTac-2000 s bidding loop there were occasions in which the network and server lags were such that it would take more than seconds to obtain updated market prices and submit bids  In this case  ATTac-2000 would either fail to buy airline tickets or worse still would buy airline tickets but not get the final hotel bids in on time Noticing that the server lag tended to be consistent within a

| Rank   |
|--------|

game instance perhaps due to the traffic patterns generated by the participating agents we introduced the adaptive timing of bidding modes described in Section After this change ATTac-200 was always able to complete at least one and usually two bidding loops in the active bidding phase The adaptive allocation strategy never came into play in the finals as ATTac-2000 was able to optimally solve all of the allocation problems that came up during the finals very quickly using the integer linear programming method However the adaptive hotel bidding did play a big role  ATTac-2000 performed as well as the other best teams in the early TAC games when hotel prices  surprisingly  stayed low and then out performed the competitors in the final games of the tournament when hotel prices suddenly rose to high levels Indeed in the last games some of the popular hotels ATTac-2000 steered clear of these hotel rooms more effectively than its closed at over $
closest competitors Table shows the scores of the   TAC finalists  Wellman et al ATTac-2000 s consistency std dev as opposed to in the preliminaries is apparent it avoided having any disastrous games  presumably due in large part to its adaptivity regarding timing and hotel bidding

| Team        | Avg                                           | S core   | St d        | Dev   | Institution   |
|-------------|-----------------------------------------------|----------|-------------|-------|---------------|
| AT Tac-2000 | A T                                           | T Labs   | Re se ar ch |       |               |
| Roxy Bot    | Brown  University   NASA   Ames  Research     |          |             |       |               |
| aster       | STAR Lab InterTrust Technologies              |          |             |       |               |
| umb ct ac   | University of Maryland at Baltimore County    |          |             |       |               |
| A LTA       | Artificial Life Inc                           |          |             |       |               |
| mra atish   | University of Tulsa                           |          |             |       |               |
| Risk Pro    | Royal Inst  Technology  Stockholm  University |          |             |       |               |
| T           | Swedish Inst  Computer Science  Industilogik  |          |             |       |               |

games

## 4.2 Controlled Testing

In order to evaluate ATTac-200 s adaptive hotel bidding strategy in a controlled manner we ran several game instances with ATTac-2000 playing against two variants of itself