Effective today, Juan A. Ochoa, CEO of the Metropolitan Pier and Exposition Authority in Chicago, has resigned. The MPEA is the municipal agency that owns and operates Chicago's McCormick Place Convention Center and Navy Pier. Ochoa has agreed to stay through a transition period, which includes the search for a new CEO. The resignation comes as the city is exploring ways to improve its trade show business, a process involving the MPEA and other city agencies, labor unions and show contractors. Ochoa has been CEO of the authority for three years; in a statement, he said, "I will move forward to work on what I believe is the central issue our country will face this century -- immigration reform, an issue of great personal importance to me."