Computer and Its Uses

Topics: Image processing, Cluster analysis, Machine learning Pages: 3 (1006 words) Published: August 21, 2013
PRI: We introduce a probabilistic version of the well-known Rand Index (RI) for measuringthe similarity between two partitions, called Probabilistic Rand Index (PRI), in which agreements and disagreements at the object-pair level are weighted according to the probability of their occurring by chance. We then cast consensus clustering as an optimization problem of the PRI value between a target partition and a set of given partitions, experimenting with a simple and very efficient stochastic optimization algorithm. Remarkable performance gains over input partitions as well as over existing related methods are demonstrated through a range of applications, including a new use of consensus clustering to improve subtopic retrieval. Definition[edit]

Given a set of  elements  and two partitions of  to compare, , a partition of S intor subsets, and , a partition of S into s subsets, define the following: * , the number of pairs of elements in  that are in the same set in  and in the same set in  * , the number of pairs of elements in  that are in different sets in  and in different sets in  * , the number of pairs of elements in  that are in the same set in  and in different sets in  * , the number of pairs of elements in  that are in different sets in  and in the same set in  The Rand index, , is:[1][2]

Intuitively,  can be considered as the number of agreements between  and  and  as the number of disagreementsbetween  and . -------------------------------------------------
Definition[edit]
Suppose we have two clusterings (a division of a set into several subsets)  and  where , , . Then the variation of information between two clusterings is:

where  is entropy of  and  is mutual information between  and . This is completely equivalent to the shared information distance. Along with Kohler and Koffka, Max Wertheimer was one of the principal proponents of Gestalt theory which emphasized higher-order cognitive processes in the midst of behaviorism. The...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Uses of Computers Essay
  • use of computer Essay
  • computer Essay
  • Use of Computers in Medicine Essay
  • Essay on The Use of Computers in Business
  • Essay about Unethical use of computers
  • Essay on The Benefits of the Use of the Computers in the Environment
  • Health Effects of Computer Use Essay

Become a StudyMode Member

Sign Up - It's Free