Department of Computer Science, University of Tokyo, Tokyo, Japan. brian@monrovian.com|Department of Computer Science, University of Tokyo, Tokyo, Japan. brian@monrovian.com|Department of Computer Science, University of Tokyo, Tokyo, Japan. brian@monrovian.com|Department of Computer Science, University of Tokyo, Tokyo, Japan. brian@monrovian.com|Department of Computer Science, University of Tokyo, Tokyo, Japan. brian@monrovian.com|Department of Computer Science, University of Tokyo, Tokyo, Japan. brian@monrovian.com|Department of Computer Science, University of Tokyo, Tokyo, Japan. brian@monrovian.com