The MiniZinc Challenge

Posted by Jon Orwant, Engineering Manager

Constraint Programming is a style of problem solving where the properties of a solution are first identified, and a large space of solutions is searched through to find the best. Good constraint programming depends on modeling the problem well, and on searching effectively. Poor representations or slow search techniques can make the difference between finding a good solution and finding no solution at all.

One example of constraint programming is scheduling: for instance, determining a schedule for a conference where there are 30 talks (that’s one constraint), only eight rooms to hold them in (that’s another constraint), and some talks can’t overlap (more constraints).

Every year, some of the world’s top constraint programming researchers compete for medals in the MiniZinc challenge. Problems range from scheduling to vehicle routing to program verification and frequency allocation.

Google’s open source solver, or-tools, took two gold medals and two silver medals. The gold medals were in parallel and portfolio search, and the silver medals were in fixed and free search. Google’s success was due in part to integrating a SAT solver to handle boolean constraints, and a new presolve phase inherited from integer programming.

Laurent Perron, a member of Google’s Optimization team and a lead contributor to or-tools, noted that every year brings fresh techniques to the competition: “One of the big surprises this year was the success of lazy-clause generation, which combines techniques from the SAT and constraint programming communities.”

If you’re interested in learning more about constraint programming, you can start at the wikipedia page, or have a look at or-tools.

The full list of winners is available here.

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The Japanese accept the US challenge

Recently I blogged about a challenge from a US mega robot manufacturer to participate in a duel with a Japanese robot company. Well the Japanese have accepted the challenge and it looks like the rumble is on! Watch this space.


from The Universal Machine http://universal-machine.blogspot.com/

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Little Box Challenge Academic Awards

Posted by Maggie Johnson, Director of Education and University Relations

Last July, Google and the Institute of Electrical and Electronics Engineers Power Electronics Society (IEEE PELS) announced the Little Box Challenge, a competition designed to push the forefront of new technologies in the research and development of small, high power density inverters.

In parallel, we announced the Little Box Challenge award program designed to help support academics pursuing groundbreaking research in the area of increasing the power density for DC-­to­-AC power conversion. We received over 100 proposals and today we are proud to announce the following recipients of the academic awards:

Primary Academic Institution	Principal Investigator
University of Colorado Boulder	Khurram K. Afridi
National Taiwan University of Science and Technology	Huang-Jen Chiu
Universidad Politécnica de Madrid	José A. Cobos
Texas A&M University	Prasad Enjeti
ETH Zürich	Johann W. Kolar
University of Bristol	Neville McNeill
Case Western Reserve University	Timothy Peshek
University of Illinois Urbana-Champaign	Robert Pilawa-Podgurski
University of Stuttgart	Jörg Roth-Stielow
Queensland University of Technology	Geoff Walker

The recipients hail from many different parts of the world and were chosen based on their very strong and thoughtful entries dealing with all the issues raised in the request for proposals. Each of these researchers will receive approximately $30,000 US to support their research into high power density inverters, and are encouraged to use this work to attempt to win the $1,000,000 US grand prize for the Little Box Challenge.

There were many submissions beyond those chosen here that reviewers also considered to be very promising. We encourage all those who did not receive funding to still participate in the Little Box Challenge, and pursue improvements not only in power density, but also in the reliability, efficiency, safety, and cost of inverters (and of course, to attempt to win the grand prize!)

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