CS 790g Seminar: Complex Networks

Fall 2010

Network Lab 1

Due on Thursday Sep 2, 2010 at 1:00 pm

Network Basics (3 points)

Go to the site http://www.visualcomplexity.com. Select and list two projects describing a network. Answer the following about them (this may require going into the source webpage for the project, linked to from the visualcomplexity site).

  1. What do the nodes and edges represent?
  2. Is the graph directed? Weighted?
  3. Can the data be represented as a bipartite graph?

Bipartite Graphs (7 points)

For this part, you may look at Pajek tutorial.

  1. Select from the draw toolbar a layout algorithm under 'Layout>'. Apply your favorite layout algorithm. Include an image.
  2. Transfrom the network into a one-mode network (Net>Transform>2-Mode to 1-Mode>Rows). Draw the network (Draw>Draw). Include an image.
  3. Qualitatively compare the structure of the 2-Mode to the 1-Mode network. Is there a loss of information?
  4. Show the weights on each edge using (Options>Lines>Mark Lines>with Values). What do the values represent?
  5. Compute the unweighted degree of each node (Net>Partitions>Degree>All). Next draw the network using (Draw>Draw-vector). How is the degree represented?
  6. Add the vector value to each vertex (it will be the degree/(max possible degree)) (Options>Mark Vertices Using>Vector Values). Include an image.
  7. Who are the most important actors using this measure?
  8. How does the boundary of the network (i.e. who is included) affect who is found to be most central?
  9. Load the file actorsandmoviesWithGere.net. It contains one extra actor, Richard Gere. Repeat the above procedure.
  10. In the 1-mode network of actors, is there a change in who is most central?
  11. What does this tell you about biases and boundaries in sample selection?
  12. Remove all edges between actors who have costarred in fewer than 3 movies (Net>Transform>Remove>Lines with value>Lower than). Which actors comprise the central core of this network?
Submitting your files

Submission of your homework is via WebCT. You must submit all the required files in a single document containing all the answers.

Acknowledgement: The assignment is modified from Lada Adamic.