托福阅读素材（一）

2018-05-04 09:42

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　　7:34

　　What other properties of language does the script show? Languages contain patterns. If I give you the letter Q and ask you to predict the next letter, what do you think that would be? Most of you said U, which is right. Now if I asked you to predict one more letter, what do you think that would be? Now there's several thoughts. There's E. It could be I. It could be A, but certainly not B, C or D, right? The Indus script also exhibits similar kinds of patterns. There's a lot of text that start with this diamond-shaped symbol. And this in turn tends to be followed by this quotation marks-like symbol. And this is very similar to a Q and U example. This symbol can in turn be followed by these fish-like symbols and some other signs, but never by these other signs at the bottom. And furthermore, there's some signsthat really prefer the end of texts, such as this jar-shaped sign, and this sign, in fact, happens to be the most frequently occurring sign in the script.

　　8:24

　　Given such patterns, here was our idea. The idea was to use a computer to learn these patterns, and so we gave the computer the existing texts. And the computer learned a statistical model of which symbols tend to occur together and which symbols tend to follow each other. Given the computer model, we can test the model by essentially quizzing it. So we could deliberately erase some symbols,and we can ask it to predict the missing symbols. Here are some examples. You may regard this as perhaps the most ancient game of Wheel of Fortune.

　　9:04

　　What we found was that the computer was successful in 75 percent of the cases in predicting the correct symbol. In the rest of the cases, typically the second best guess or third best guess was the right answer. There's also practical use for this particular procedure. There's a lot of these texts that are damaged. Here's an example of one such text. And we can use the computer model now to try to complete this text and make a best guess prediction. Here's an example of a symbol that was predicted. And this could be really useful as we try to decipher the script by generating more data that we can analyze.