东北大学数据挖掘第2章.ppt

* CC (conference call) 08.11.02: Need to check Wiki to update references. * CC (conference call) 08.11.02: Need to check Wiki to update references. * CC 08/11/02: Need a good survey. JH or JP may find a good book on amazon in order to update this slide. JH’s colleagues may generate some images for book. We may consider the following books. Visualizing Data: Exploring and Explaining Data with the Processing Environment - Paperback - Illustrated (Jan 11, 2008) by Ben Fry. JH: I have ordered the book. * /companions/1558606890/pictures/Chapter_01/fig1-6b.gif * * * * * * * “two attributes mapped to axes, remaining attributes mapped to angle or length of limbs”. Look at texture pattern. * MK 08/10/18: Is it “Treemap” or “Tree-Map”? - inconsistent in this file. * * * * Picture: /hcil/treemap-history/ * JH: I have not found a good infocube picture on the web * /articles/visualization * Keep here because keeping it in clustering chapter seems far away. 08.11.02 * Distance is just once way of measuring dissimilarity (wiki). Changed “register only the distance” to “registers only the difference” or “dissimiarity”? * Cosine Similarity A document can be represented by thousands of attributes, each recording the frequency of a particular word (such as keywords) or phrase in the document. Other vector objects: gene features in micro-arrays, … Applications: information retrieval, biologic taxonomy, gene feature mapping, ... Cosine measure: If d1 and d2 are two vectors (e.g., term-frequency vectors), then cos(d1, d2) = (d1 ? d2) /||d1|| ||d2|| , where ? indicates vector dot product, ||d||: the length of vector d document team coach hockey baseball soccer penalty score win loss season document1 5 0 3 0 2 0 0 2 0 0 document2 3 0 2 0 1 1 0 1 0 1 document3 0 7