In a data warehouse system the computation of measures might change over time. Companies that try various ways to handle discount will cause even the simplest measures such as net sales to be subject to change. Complex measures as one can observe them in Big Data settings are more liable to this effect.
Slowly Changing Measures is a concept to make these changes obvious in reports and prevents reports from becoming invalid.
A Method and an Apparatus for Clustering Process Models. US-Patent No. 8180627 explained
Should We Combine Genetic Algorithms and K-Means-Like Clustering Algorithms?