CIS 6930: Approximation Algorithms
Announcements   |       Syllabus       |        Schedule        |       Lecture Notes        |     Assignments 
  • The last homework assignment will be due on Dec 4th.
  • The "final presentation" of group project is scheduled on Nov 29th. Each team will have about 30 mins for the presentation. If needed, we will extend the presentation to Dec 4th.
  • Requirements of the presentation:
    • Clearly define your problem definition and assumptions
    • Background of related work
    • Your solutions and experiment results
  • Other non-group members will write the comments/suggestion on the solutions and pass to the group members at the end of each presentation
  • Homework assignment 3 has been posted.
  • Lecture notes for the rest of this semester have been posted.
  • Office hour on Wednesday (10/03/07) will be moved to Thursday (10/04/07) at the same time (1:15-2:15pm)
  • Notes on Bin Packing and k-Center (for week 7) have been posted.
  • Research topics chosen by each team:
    • Team 1: Multicast
    • Team 2: Dominating Tree
    • Team 4: General CDS with diameter
    • Team 3: TBA
  • Possible research problems for group projects:
    • Connected Dominating Set (CDS) with Bounded Diameter: Given a Unit Disk Graph G=(V,E), find a  CDS V' such that V' has a minimum size and minimum diameter, where diameter is defined as the longest path of all shortest paths between any pair of vertices in V'.
    • General CDS with Bounded Diameter: Similar to the above, plus: G[V'] is k-connected and for any vertex u not in V', u is adjacent to at least m vertices in V'.
    • Multicast: Given a graph G=(V,E) with the cost function: c: E -> [0,1],  two vertices s and d in V, and an integer k.. Find a connected subgraph G' = (V', E') of G such that s, d are in V', c(E') is maximum, and |E'| <= k.
    • Coverage Problem: Given a bipartite graph G=(X,Y;E) where X is a set of sensors, Y is a set of targets, and E is a set of edges representing the coverage relationship between X and Y, that is, an edge (x,y) \in E where x \in X, y \in Y, iff sensor x can cover target y. If the sensor x is active for a unit time, it will use k energy. If x is in the sleep mode, it will use no energy. Assume that each sensor has at most K energy. Find a set of ordered pair (X_j, t_j) where X_j is the set of sensors need to be active during the time duration t_j such that: each target can be covered by at least m sensor in X_j, the sum of all t_j is maximum, and the energy consumption of any sensor x for the whole time must be at most K.
    • d-disjunct submatrix: Given a binary matrix M with size m x n. Find a submatrix H with size t x n such that t <= m, H is d-disjunct, and t is minimum.
    • Community Structure: Given a graph G=(V,E) and the cost function c: E -> R+, partition the graph into a set of connected subgraph such that: each vertex is in exactly one subgraph, the cost of all subgraphs is maximum (where cost of a subgraph = cost of all edges in that subgraph), vertices in each subgraph are highly connected (compared with outside vertices)
    • Broadcast Schedule: Given a directed disk graph G=(V,E), a source vertex s. Find the broadcast schedule for s with minimum time latency such that there is no conflict and collision.
  • Homework assignment 2 has been posted.
  • There will be no lecture next Tuesday (09/25). Instead, each team will meet me (at my office) to discuss about the topics of their project:
    • Team 1: 10:40am-10:55am
    • Team 2: 10:55am-11:10am
    • Team 4: 11:10am-11:25am
    • Team 3: 11-25am-11:40am
  • We have formed four teams as follows:
    • Team 1: Ashish (, Erhun (, Ying (
    • Team 2: Cem (, Ravi (, Bo (
    • Team 3: Feng (, Reza (, Venkatakris (
    • Team 4: Jarret (, Incheol (, Ning (
  • Tomorrow's lecture (09/11) will be cancelled due to my illness.
  • Homework assignment 1 has been posted.
  • Notes on the Greedy Strategy have been posted. They are new materials and not provided in the text book. We will cover them over next four weeks, including the following topics:
    • Independent System
    • Submodular Function
    • Non-submodular Function
    • Problems: Max Hamiltonian Cycle, Shortest Superstring, Connected Dominating Set, General Set Cover
  • I will update this file as we go along.
  • Welcome to CIS6930. Enjoy and have fun learning!
CIS 6930: Approximation Algorithms