Some basic concepts of Data Mining

Source: Internet
Author: User
Tags idf

Modeling Method:

1: Data Summary:

Eg: PageRank

Data is used to reflect the importance of a Web page, that is, the probability that a random user is on this page.

2: Clustering

3. Feature Extraction

1: frequent itemset:

Eg: most users buy A and B at the same time. When a user buys a, B is recommended to him.

2: similarity item similar item: Collaborative Filtering

Search for similar users or products for recommendation

The theory of bonefrani: positive correlation between pancreatic production, that is, when a specific feature is searched for in certain data, even if the data is completely random, the feature will appear and increase as the data grows.


TF: Word Term Frequency

TF (ij) = f (ij)/maxk F (kJ)

That is, in document J, the frequency of word item I is the frequency of word item I divided by the frequency of word item k with the highest frequency (normalization without considering deprecated words)

IDF: Frequency of inverse document

Assume that the number of documents is N. If word item I appears in N (I) documents, the IDF of word item I is:

IDF (I) = Log (2) n/n (I)

Not complete...

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.