Bottom-up modeling, Bottom-up analysis

An anpproach which starts with the lowest level and moves in the direction of aggregation. Imagine a organization chart. The box at the top of the chart would represent the President or Chairman. Division Chiefs might follow at the next level down, and so on until the lowest level job was described. A “bottom up” analysis of, say, the reasons for success of the organization would start with the lowest level and engage people in those assignments with questions about their contributions. In contrast, a “top down” analysis would begin with the President or Chairman with similar questions. The term can be applied to many situations, for example: (material following is based on Wikipedia: http://en.wikipedia.org/wiki/Protein_mass_spectrometry and http://en.wikipedia.org/wiki/Bottom- up) In business development, a bottom-up approach means that the adviser takes the needs and wishes of the would-be entrepreneur as the starting point, rather than a market opportunity (which would be a 'top-down' approach). Top-down and bottom-up design, a term in information processing and systems theory Bottom-up parsing, a computer science strategy Bottom-up (finance) Fundamental analysis, analyzing a business from its elements Bottom-up testing Integration testing, a phase in software testing Bottom-up proteomics, a laboratory technique involving proteins, in which intact proteins are ionized then introduced to a mass analyzer. This approach is referred to as a "top-down" analysis. In contrast, in a bottom-up analysis, proteins are enzymatically digested into smaller peptides which are introduced into a mass spectrometer and identified by peptide mass fingerprinting or tandem mass spectrometry.