1. HITs Implementation
Presented by the Amazingly Brilliant John Yankowski and the slightly less brilliant Larry Phillips

2. Eigen Values and Vectors
Av = λv (λ is the Eigenvalue)
Each λ corresponds to one Eigenvector v
I don’t know what this means, but Google seems to think its related to Eigen somehow.

3. The POWER Method!!!! x(k+1) = Ax(k) xk -> Dominant Eigenvector
Hey John, What about other methods??

4. Computing the ultimate authority and hub scores x and y

5. Steps Step 1 Initialize y(0) = e; e is a column vector of all ones
Step 2 take x(k) = Lt y(k-1) , y(k) = Lx(k) and simplify to get…

6. x(k) = Lt L x(k-1) y(k) = L Lt y(k-1)
Computes the dominant eigenvector for the matrices LT L (Authority matrix) and L LT (Hub Matrix)

7. Benefits of using the dominant eigenvectors of LTL and LLT
Incurs a small cost in comparison with using scores from all documents on Web
Only one document eigenvector needs to be computed: (LTL or LLT)

8. Authoritative and Hub Matrices
Authoritative means the links are to the website
Hub means the the links shoot out from the website

9. Mexican Hats? Yes, Mexican hats.
We submit a query that results in pages 1 and 6, where 1 happens to point to 6

10. But Hey, What about Sombreros??
Related nodes can be added to a limited extent to make the search more comprehensive

11. I need Mexican Hats!
The query results in Matrix L

12. MSPaint Matrices are Awesome!
From L, we can find the Authoritative and Hub Matrices.

13. HITs successfully refines the score by computing
Xi(k) = Σ yj(k-1)
Can be written as X(k) = LTy(k-1) which is the power method that will give you the dominate eigenvector

14. Dangerously close to a Mexican hat, so we’ll count it
We have vectors, weee!!!
xT = ( )
yT = ( )
Why John, Don’t those add up to 1?
Why yes they do, and thank you for asking.
These numbers give you the ranking for all your Mexican hat web pages.
Auth. Ranking = ( )
Hub Ranking = ( )
Dangerously close to a Mexican hat, so we’ll count it

15. Bibliometricity Yeah, it’s a big word, and we know it
Refers to two documents that are in-laws (related through association).

16. How does Bibliometricity apply to mexican hats?
LTL = Din + Ccit
LLT = Dout + Cref
Mexican Hat in action

17. How does this apply to the real world?
is a search engine that uses hits technology.