Different subfields of AI (Robotics, Computer Vision, NLP, ML, etc) have been holding contests by defining a standard task and challenging researchers to do their best. Examples include the International Planning Competition, the DARPA Urban Challenge for robotic cars, the Robocup robotic soccer league, the TREC (Text Retrieval Conference), the PASCAL Visual Object Classes challenge, and contests in speech recognition and machine translation. Investigate three of these contests, and briefly describe the progress made over the years. To what extent have the contests advanced the state of the art in AI?