Considering the temperate spring weather, it was not surprising to see students flock to a soccer game last weekend to support their friends and classmates. What was surprising was that the spectators actually withdrew from the 60-degree temperatures outside to do so.

Then again, this was no ordinary Bowdoin soccer match. Instead of taking place on an expansive outdoor pitch near Farley Field House, it was played in a small, makeshift indoor arena in Daggett Lounge. Rather than taking aim at an NCAA tournament bid, the team was preparing to compete for a world championship.

And the players were not Bowdoin undergraduates. They were robots.

Last Friday, a crowd gathered in Daggett Lounge to watch as Bowdoin's robotics team held an intra-squad scrimmage with their team of artificially intelligent robotic dogs in preparation for this weekend's U.S. Open robot soccer tournament in Atlanta. It is the second straight year and the second time ever that Bowdoin has entered a team in the national competition. In June, the team will vie for a RoboCup world championship in Bremen, Germany, for the first time, pending the procurement of necessary funds.

The team's faculty advisor, Associate Professor of Computer Science Eric Chown, was introduced to robotic dog soccer several years ago by a Bowdoin alumnus, Doug Vail, who was involved with the national champion Carnegie Mellon University team. Chown then decided to use part of a $320,000 grant he had been awarded by the National Science Foundation (NSF) to help launch a robotics project at Bowdoin.

Last year, one student, Greydon Foil '05, entered a team in the national RoboCup tournament as an advanced independent study. This year, the team grew to eight. Overall, Chown estimated that between 18 and 20 students have contributed to this year's project in some way.

The robotic dogs are commercial products made by Sony called "AIBOs," which cost approximately $2,000 each. Once programmed, they are theoretically autonomous, capable of processing visual and auditory stimuli from their external environment and adapting their behavior accordingly.

Using money from his NSF grant, Chown has bought 12 AIBOs over the last few years. This year, the College paid for four additional AIBOs.

Using Mac OS 10 operating systems with C++, Java, and Python programming languages, the students taught the AIBOs how to react to the ball and other players, and how to use visual reference points to orient themselves on the playing field.

The students accomplished this by filtering the camera feed from each dog's snout to include only the particular pixel arrangements (colors) that are relevant to the soccer game, such as the bright orange ball or the yellow goal posts. The students then programmed each AIBO to analyze and interpret the objects in its visual field, to move, and to communicate.

Chown said that each AIBO calculates its position on the field 20 times per second.

Each AIBO "dribbles" the ball by wedging it between the bottom of its mouth and its chest. To make a shot, it rocks back on its haunches and slides down and forward, striking the ball with its chest. To block shots, a goalie will lay flat on its chest with its four legs spread out on either side of its body.

While the robots' movements are somewhat comical to watch, the programming that underlies those movements is meticulous. In order to teach each AIBO how to execute a motion, Henry Work '06 and the other motion technicians had to teach each segment of the robot's body to move in a certain way relative to the other segments. This was after the students worked exhaustively to figure out what patterns of movement created the most efficient and effective soccer motions.

Operating with a significantly smaller budget than other schools' robotics projects, members of the Bowdoin team have succeeded in staying on the cutting edge of robotic science. This year, Chown, Foil, Work, and sophomore Yi Zhuang co-authored a paper that was published by the Florida Artificial Intelligence Research Society (FLAIR). Work and Chown will travel to a FLAIR conference in May.

When the Bowdoin team competes in the national and international RoboCup tournaments, they will be squaring off against teams of graduate students from large research universities, many of whom have committed the entirety of their academic energies toward perfecting their robots' skills. While Chown hopes for the best, he remained realistic about Bowdoin's chances.

"If we can win a match or two in Germany, I'll be happy," he said. "At this point, it's really more about the experience for the students."

"We want to do well," said Work, "but we understand that a big part of the project is scientific endeavor."

Work has been pleased with how the RoboCup project has united Bowdoin students who are enthusiastic about artificial intelligence technology.

"I'm very happy that we have computer science students working together, because in general, the computer science department can be a bit disparate," he said.

Work said that last Friday's scrimmage exposed weaknesses with the AIBOs' ability to calibrate their vision programs to new lighting, a problem that the team hoped to correct before this weekend's U.S. Open competition.

"We try to know our systems very well so that we can make changes on the fly," he said.

Chown said that he was "thrilled" with Friday's scrimmage, but agreed that there are several flaws that needed to be ironed out.

"Our decision-making still needs to be faster, our goalie needs to improve a lot, and our vision system needs to be more robust," he wrote in an email to the Orient.

While the purpose of the exhibition was to test for defects in the AIBOs' programming, it also gave Bowdoin students, faculty, staff, and alumni a chance to see the product of the student technicians' labor. The event drew a large crowd whose enthusiasm compared to that at any College athletic event.

Each goal sent the spectators into a tumult, and the referees' judgments elicited several lighthearted catcalls. Some students even heckled the non-sentient athletes.

"Where's the fire, red?" shouted one onlooker after the blue team scored a quick goal.

Antics aside, those who attended the scrimmage were generally impressed with the artificially intelligent AIBOs and their programmers.

"This is one of the coolest things I've seen at Bowdoin," said Alex White '08.

"It's phenomenal," agreed Matt Martin '07. "They're going to take over the MLS (Major League Soccer) someday."