Curriculum Vitae

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Please e-mail any and all questions to chang6 [at] fas [dot] harvard [dot] edu.

2009 COMAP MCM PAPER

For the 2009 COMAP Mathematical Contest in Modeling, I again worked with my roommates Yi Sun and Zhou Fan to write a paper titled A Simulation Based Model of Traffic Circles (Problem A). The paper will be published in the UMAP (Undergraduate Mathematics) Journal. The formal problem statement for the 2009 contest is as follows:

Many cities and communities have traffic circles.from large ones with many lanes in the circle (such as at the Arc de Triomphe in Paris and the Victory Monument in Bangkok) to small ones with one or two lanes in the circle. Some of these traffic circles position a stop sign or a yield sign on every incoming road that gives priority to traffic already in the circle; some position a yield sign in the circle at each incoming road to give priority to incoming traffic; and some position a traffic light on each incoming road (with no right turn allowed on a red light). Other designs may also be possible. The goal of this problem is to use a model to determine how best to control traffic flow in, around, and out of a circle. State clearly the objective(s) you use in your model for making the optimal choice as well as the factors that affect this choice. Include a Technical Summary of not more than two double-spaced pages that explains to a Traffic Engineer how to use your model to help choose the appropriate flow-control method for any specific traffic circle. That is, summarize the conditions under which each type of traffic-control method should be used. When traffic lights are recommended, explain a method for determining how many seconds each light should remain green (which may vary according to the time of day and other factors). Illustrate how your model works with specific examples.

We also won an "outstanding" award in addition to the SIAM award for our paper, the highest honor awarded.

2008 COMAP MCM Paper

For the 2008 COMAP Mathematical Contest in Modeling, I worked with my roommates Yi Sun and Zhou Fan to write hsolve: A Difficulty Metric and Puzzle Generator for Sudoku as our response to the discrete problem (Problem B).

The formal problem statement for the 2008 contest is as follows:

Develop an algorithm to construct Sudoku puzzles of varying difficulty. Develop metrics to define a difficulty level. The algorithm and metrics should be extensible to a varying number of difficulty levels. You should illustrate the algorithm with at least 4 difficulty levels. Your algorithm should guarantee a unique solution. Analyze the complexity of your algorithm. Your objective should be to minimize the complexity of the algorithm and meet the above requirements.

We were advised by Clifford Taubes, the Harvard William Petschek Professor of Mathematics. Our paper was published in the UMAP (Undergraduate Mathematics) Journal. For this paper, I attended the annual SIAM conference in San Diego during the summer of 2008 to give a presentation on my team's paper since we won the SIAM award and were selected as an "outstanding" team, the highest honor awarded (Problem B).