-
Notifications
You must be signed in to change notification settings - Fork 5
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
11 changed files
with
847 additions
and
406 deletions.
There are no files selected for viewing
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Large diffs are not rendered by default.
Oops, something went wrong.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,58 @@ | ||
--- | ||
title: "**Applications of Topology in Networks**" | ||
output: html_document | ||
--- | ||
|
||
```{r setup, include=FALSE} | ||
knitr::opts_chunk$set(echo = TRUE) | ||
``` | ||
## Part 2 | ||
|
||
<br> | ||
|
||
#### **Graph Persistent Homology** | ||
|
||
**#Edge Activations** | ||
|
||
* Consider the graph below where edge weights indicate distances. | ||
|
||
* Lets use a Vietoris Rips complex: denoted as Ripsɑ(X), consists of simplices [x0,...,xk] satisfying the condition that the distance between any pair of points, dx (xi, xj), is less than or equal to a for all (i, j). | ||
<center> | ||
![Let’s define a filtration scale parameter which we will increase from a minimum to a maximum.](Images/dots.png){width=30%} | ||
</center> | ||
|
||
* Min scale = 0 (we could start from 0.5 or any other value as well) | ||
|
||
* Max scale = 100 (we could go longer, but it would not change anything) | ||
<center> | ||
![](Images/dots2.png){width=80%} | ||
</center> | ||
|
||
* Multiple questions: | ||
* Question 1: How do we define a distance based on edge weights? In the previous slide, the edge weights represented distances, eliminating the need for explicit distance definition. | ||
* Question 2: What happens if the graph is unweighted? | ||
1. Graph resistance distance: In a graph, the resistance between two vertices measures the level of difficulty for electric current to flow between them. | ||
2. Shortest path distance (works with weighted edges as well): a measure of the minimum number of edges along the shortest path between two vertices in a graph. | ||
3. Ricci curvature (works with weighted edges as well): the concept of Ricci curvature is a generalization of Ricci curvature from Riemannian geometry. It provides a way to quantify the geometric properties of the network based on its connectivity and edge weights. | ||
<center> | ||
![](Images/image5.png){width=60%} | ||
</center> | ||
* Question 3: What happens if the graph is directed? | ||
* Use distance measures introduced in the first question, but define distances based on incoming or outgoing edges only | ||
|
||
**#Node Activation** | ||
|
||
* Consider the graph below where node features indicate ages. | ||
<center> | ||
![](Images/image6.png){width=30%} | ||
</center> | ||
* We will use sub or super level filtration. | ||
* Sublevel: filtration from minimum to maximum scales | ||
* Superlevel: filtration from maximum to minimum scales | ||
|
||
* Min scale = 10 (we could start from 15 or any other value as well) | ||
|
||
* Max scale = 80 (we could go longer, but it would not change anything) | ||
<center> | ||
![](Images/Image7.png){width=80%} | ||
</center> |
Large diffs are not rendered by default.
Oops, something went wrong.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters