这这一课程中，我们将学习数据挖掘的基本概念及其基础的方法和应用，然后深入到数据挖掘的子领域——模式发现中，学习模式发现深入的概念、方法，及应用。我们也将介绍基于模式进行分类的方法以及一些模式发现有趣的应用。这一课程将给你提供学习技能和实践的机会，将可扩展的模式发现方法应用在在大体量交易数据上，讨论模式评估指标，以及学习用于挖掘各类不同的模式、序列模式，以及子图模式的方法。

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來自 University of Illinois at Urbana-Champaign 的課程

Pattern Discovery in Data Mining

194 個評分

这这一课程中，我们将学习数据挖掘的基本概念及其基础的方法和应用，然后深入到数据挖掘的子领域——模式发现中，学习模式发现深入的概念、方法，及应用。我们也将介绍基于模式进行分类的方法以及一些模式发现有趣的应用。这一课程将给你提供学习技能和实践的机会，将可扩展的模式发现方法应用在在大体量交易数据上，讨论模式评估指标，以及学习用于挖掘各类不同的模式、序列模式，以及子图模式的方法。

從本節課中

Module 2

Module 2 covers two lessons: Lessons 3 and 4. In Lesson 3, we discuss pattern evaluation and learn what kind of interesting measures should be used in pattern analysis. We show that the support-confidence framework is inadequate for pattern evaluation, and even the popularly used lift and chi-square measures may not be good under certain situations. We introduce the concept of null-invariance and introduce a new null-invariant measure for pattern evaluation. In Lesson 4, we examine the issues on mining a diverse spectrum of patterns. We learn the concepts of and mining methods for multiple-level associations, multi-dimensional associations, quantitative associations, negative correlations, compressed patterns, and redundancy-aware patterns.

- Jiawei HanAbel Bliss Professor

Department of Computer Science

[SOUND]

The first thing we want to discuss is,

The Limitation of the Support Confidence Framework.

As we know, pattern mining may generate a large number of rules but

not all of the patterns and rules generated are interesting.

In general we can classify the interesting measures into two classes,

objective versus subjective.

For objective measure like support, confidence,

correlation are defined by mathematical formulas,

not change from person to to person.

But the subjective measure may change from person to person,

because one man's trash could be another man's treasure.

So the first thing, is we may want a user to say, what do you like to see?

So it's query based.

Another thing is we may base on user's knowledge base,

try to mine something unexpected, fresh or recent.

Or we can map patterns and rules into two-dimensional space,

let user to interactively pick some interesting things.

So we know we have support and

confidence as two interestingness measures in association rules.

So we may be careful about this, because not all the strong

support and confidence rules are interesting.

For example, take the following table, a 2-way contingency table,

to look at this to see how to interpret things we found.

For example, in this table, 400 out of 1000 students play basketball and

eating cereal, but 200 students, they play basketball but they may not eat cereal.

In this one, you may derive association rule like this.

Playing basketball implies eating cereal.

You probably will get a 40% support because it's 400 over 1,000.

You will get two thirds of the confidence because you get 400 over 600.

So this is pretty high support and confidence.

Is this really interesting?

Let me try another rule regenerated.

Actually you will see, if we say not playing basketball, eating cereal.

You will see not playing basketball is 35%, with the confidence even higher,

because they have 350 eating cereal out of 400 people.

So this one is even higher.

So, if you recommend these two rules to the cereal company,

they will get confused.

They'll say, the first rule say that I better give some free basketball

because if they play basketball, eating cereal.

The second rule say I better take their basketball away,

because if they do not play basketball they actually eat cereal even more.

Which one is right?

Let's examine it.

[MUSIC]