Event(s) on July 2007

• Tuesday, 17th July, 2007

  Title:	Multi-Instance Learning Revisited
  Speaker:	Prof. Zhi-Hua Zhou, Department of Computer Science & Technology, Nanjing University, China
  Time/Place:	11:00  -  12:00 FSC 1217
  Abstract:	In this talk I will start by an introduction to multi-instance learning (MIL) and semi-supervised learning (SSL). Then I will show that although these two machine learning branches were almost separately developed, there exists some relationship between them. That is, by assuming i.i.d. instances, MIL can be regarded as a special case of SSL. In a further discussion, I argue that although most previous MIL studies assumed i.i.d. instances explicitly or implicitly, such an assumption should not be taken by future MIL research.

  
  

• Tuesday, 31st July, 2007

  Title:	Algorithms for Weighted Shortest Paths Problems
  Speaker:	Prof. Joerg Sack, School of Computer Science, Carleton University, Canada
  Time/Place:	11:00  -  12:00 FSC 1217
  Abstract:	Shortest path problems are among the fundamental problems studied in computational geometry and other areas including graph algorithms, geographical information systems (GIS) and robotics. Existing algorithms for many of the interesting shortest path problems are either very complex and/or have very large time and space complexities. Hence they are unappealing to practitioners and pose a challenge to theoreticians. This coupled with the fact that the geographic/spatial models are approximations of reality anyway and high-quality paths are favored over optimal paths that are “hard'' to compute, approximation algorithms are suitable and necessary. We present algorithms to compute approximations of shortest paths (Euclidean or weighted) between a source and target vertex on the surface of a polyhedron P. In the weighted shortest path problem each face has a positive non-zero real valued weight representing the cost of travelling through that face. The algorithms discussed provide a substantial improvement in the time complexity and are of practical value as demonstrated through a series of experiments on triangular irregular networks. We also provide an algorithm for computing a weighted shortest path in a subdivision of R3.