Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!swrinde!ucsd!sdcc6!beowulf!demers From: demers@beowulf.ucsd.edu (David Demers) Newsgroups: comp.ai.neural-nets Subject: Re: Clustering Message-ID: <19703@sdcc6.ucsd.edu> Date: 24 May 91 00:48:33 GMT References: <1991May20.203008.27681@noose.ecn.purdue.edu> Sender: news@sdcc6.ucsd.edu Organization: CSE Dept., UC San Diego Lines: 40 In article reynolds@park.bu.edu (John Reynolds) writes: >>>>>> On 21 May 91 14:10:44 GMT, greenba@gambia.crd.ge.com (ben a green) said: >ben> Clustering is a way to sort things into groups that share similarities. >ben> If you already know the classes to which the things belong, what's the >ben> point of trying to cluster them? ->>In addition to code compression, which is a consequence of both ->>supervised and unsupervised clustering, some supervised clustering ->>algorithms can allow generalization. Some systems can tessellate the ->>input space into homogeneous regions containing only patterns of a ->>single class. If such regions can be identified, then an informed ->>guess can be made about the class membership of future, unlabeled ->>patterns, and they can be treated accordingly. ->>Moreover, it is often inappropriate to group patterns according to ->>ostensible similarity because the values of important variables may ->>not be known. Two objects may appear similar but they may differ in ->>unknown but important variables. ->>Some supervised clustering algorithms can locally warp the similarity ->>metric so that functionally similar patterns are grouped together and ->>vice versa. Dimensions which are useful in separating functionally ->>different classes of objects are enhanced, and irrelevant dimensions ->>are compressed. OK, sounds interesting. I too naively thought clustering was an unsupervise method. But in Duda & Hart, Jain, nor Hartigan I can not locate anything about supervised clustering. Anyone have any references? Dave -- Dave DeMers demers@cs.ucsd.edu Computer Science & Engineering C-014 demers%cs@ucsd.bitnet UC San Diego ...!ucsd!cs!demers La Jolla, CA 92093-0114 (619) 534-8187,-0688 ddemers@UCSD