At the core of the CMUnited-98 coordination mechanism is what we call the Locker-Room Agreement [10]. Based on the premise that agents can periodically meet in safe, full-communication environments, the locker-room agreement specifies how they should act when in low-communication, time-critical, adversarial environments.
The locker-room agreement includes specifications of the flexible teamwork structure (Section 5.3) and the inter-agent communication paradigm (Section 5.5). A good example of the use of the locker-room agreement is CMUnited-98's ability to execute pre-compiled multi-agent plans after dead-ball situations. While it is often difficult to clear the ball from the defensive zone after goal kicks, CMUnited-98 players move to pre-specified locations and execute a series of passes that successfully move the ball out of their half of the field. Such ``set plays'' exist in the locker-room agreement for all dead-ball situations.
A new addition to CMUnited-98's locker-room agreement is a defensive
offsides strategy. Since the rules of the soccer server prohibit an
opponent from receiving a pass when located behind the last defender
on the opponent's attacking half of the field
, it is
an effective defensive strategy to move all the defenders forward
towards midfield. However, if only one defender is farther back than
the rest of the team, the strategy can back-fire horribly.
To take advantage of this rule using the locker-room agreement, the team agrees on a formula based on the location of the ball and the opponent's furthest-back defender. This strategy relies on relatively consistent sensing by all of the defensive players, but it does not require any communication. Independently, the players can dynamically adjust their positions as the ball and opponents move so that the team's defenders stay in a coordinated line.
The CMUnited-98 offsides line was always at least 15 meters behind the current ball position to prevent opponents from dribbling through to goal and at least 40 meters behind the opponents last defender to allow enough room in the midfield to pass the ball amongst teammates.