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This is Scientific American’s 60-SecondScience. I’m Steve Mirsky. Got a minute?

The traveling salesman problem is afavorite math conundrum¹: if a salesman has to visit a bunch of cities, how doyou get him to all of them once via the shortest possible route. But thetraveling salesman's predicament pales in comparison to figuring out the bestways to get four-man crews of umpires to every major league baseball game. Aresearch team attacked the problem for the last few years. Their solutionappears in Interfaces². It's a journal of operations research.

In addition to minimizing travel, here aresome of the umpire constraints³. Crews should visit each MLB city at least once.They should work each team at home and on the road. They should not work morethan 21 days in a row. They should not ump any one team’s games for more thanfour series all year. There are plenty more.

The researchers first had to develop thequestion, dubbed⁴ the "traveling umpire problem." They usedbrute-force computation and heuristics for their solutions. The result was goodenough for Major League Baseball to adopt the last three seasons. Previously⁵, aformer umpire made the schedule. That guy is out.

Thanks for the minute. For ScientificAmerican’s 60-Second Science. I’m Steve Mirsky.

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收听单词发音

1 conundrum
n.谜语；难题
参考例句：
Let me give you some history about a conundrum.让我给你们一些关于谜题的历史。 Scientists had focused on two explanations to solve this conundrum.科学家已锁定两种解释来解开这个难题。

2 interfaces
界面( interface的名词复数 )；接口（连接两装置的电路，可使数据从一种代码转换成另一种代码）；交界；联系
参考例句：
If the class needs to be reprogrammed, new interfaces are created. 如果class需要重新程序设计，新的interfaces创建。 Interfaces solve this problem of evolving code. Interfaces解决了代码升级的问题。

3 constraints
强制( constraint的名词复数 )；限制；约束
参考例句：
Data and constraints can easily be changed to test theories. 信息库中的数据和限制条件可以轻易地改变以检验假设。来自英汉非文学 - 科学史 What are the constraints that each of these imply for any design? 这每种产品的要求和约束对于设计意味着什么？来自About Face 3交互设计精髓

4 dubbed
v.给…起绰号( dub的过去式和过去分词 )；把…称为；配音；复制
参考例句：
Mathematics was once dubbed the handmaiden of the sciences. 数学曾一度被视为各门科学的基础。 Is the movie dubbed or does it have subtitles? 这部电影是配音的还是打字幕的？来自《简明英汉词典》

5 previously
adv.以前，先前（地）
参考例句：
The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。 Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。