Problem With Previous Methods
Previous clustering algorithms performed less effectively over very large databases and did not adequately consider the case wherein a data-set was too large to fit in main memory. As a result, there was a lot of overhead maintaining high clustering quality while minimizing the cost of addition IO (input/output) operations. Furthermore, most of Birch's predecessors inspect all data points (or all currently existing clusters) equally for each 'clustering decision' and do not perform heuristic weighting based on the distance between these data points.
Read more about this topic: BIRCH (data Clustering)
Famous quotes containing the words problem, previous and/or methods:
“The problem for the King is just how strict
The lack of liberty, the squeeze of the law
And discipline should be in school and state....”
—Robert Frost (1874–1963)
“I will frankly declare, that after passing a few weeks in this valley of the Marquesas, I formed a higher estimate of human nature than I had ever before entertained. But alas! since then I have been one of the crew of a man-of-war, and the pent-up wickedness of five hundred men has nearly overturned all my previous theories.”
—Herman Melville (1819–1891)
“A woman might claim to retain some of the child’s faculties, although very limited and defused, simply because she has not been encouraged to learn methods of thought and develop a disciplined mind. As long as education remains largely induction ignorance will retain these advantages over learning and it is time that women impudently put them to work.”
—Germaine Greer (b. 1939)