Changes between Version 2 and Version 3 of RdsWipWorldView/TemplateMethodologies

Show
Ignore:
Timestamp:
09/02/08 00:40:25 (16 years ago)
Author:
jbourne (IP: 70.48.152.174)
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • RdsWipWorldView/TemplateMethodologies

    v2 v3  
    3030That is to say, the intersection of '''modeling system''' ''and''  '''methodology''' together select the working set of definitions. 
    3131 
    32 == Top-Down Approach == 
     32== Coarse-to-Fine Approach == 
    3333 
    34 @todo describe 
     34A coarse-to-fine approach takes relationships that already exist in highly agglutinated or generalized forms and then ''may'' break them down into finer relationships in order to explore the structure of the data. 
    3535 
    36 == Bottom-Up Approach == 
     36It is important to recognize that often they need not break them down much if at all - often, models built with this approach are purely for the recording of the data, without much emphasis placed on the analysis of the structure, beyond a certain level necessary to solve specific problems. 
    3737 
    38 @todo describe 
     38Constraints on the structure of the data 
     39 
     40Coarse-to-fine approaches are typically empirical or based on actual data - they model information as it is recorded by humans or other systems.  This exploits two very important features: 
     41 
     42 * it is often purpose-driven - the model fits the data because it has been 
     43   developed as an abstraction of the patterns already in the data. 
     44 
     45 * it tends to reflect the way that humans think about the data in the 
     46   disciplines that work with the problem set. 
     47 
     48Most data model design processes follow this approach - not because it necessarily results in the best possible model, but because it quickly results in a model that fits the problem and the data fast. 
     49 
     50Perhaps more importantly, it is popular because it is successful, and it is successful because it does not challenge the participants to alter the way they think about the structure of the data. 
     51 
     52Note: this is not an obsequious comment - humans are not logical, humans think by making generalizations about observable patterns, and such generalizations need not be comprehensive; that is to say it is implicit that the generalizations are not intended to necessarily cover all cases.  Human language is built to communicate these kinds of observable patterns or cases which fit them. 
     53 
     54Frequently, this means that humans hold to lore that while useful, might not be correct.  But its usefulness extends beyond its value as an approximation, or a rule of thumb - it is useful because human languages makes it concise to communicate to other humans (because human language is based on the same principles - generalizations not intended to be comprehensive in scope). 
     55 
     56As a result, these kinds of approaches can only be used for interoperability where the problem-set is roughly shared across the communicating parties - that is to say, if one party wants to use this data to solve a different problem, there is a good chance it is actually useless to them. 
     57 
     58 
     59== Coarse-to-Fine Approach == 
     60 
     61The [wiki:RdsWipWorldView/CoarseToFine Coarse-to-Fine] approach takes information and models it in its extant form (as it is exposed from language, data or usage).  It then breaks down those "coarse" relations into finer relations to the depth required to address a specific problem set. 
     62 
     63== Fine-to-Coarse Approach == 
     64 
     65The [wiki:RdsWipWorldView/FineToCoarse Fine-To-Coarse] approach seeks to model information from a set of founding principles.  These principles determine an starting set of finely-grained relations from which successively coarser and coarser sets of relations are built, until (perhaps) relations that are generally useful for solving specific problem sets can be reached. 
    3966 
    4067== The Reach of a Methodology == 
    4168 
    42 Top-down approaches have a tendency to be more neutral to a modeling system - the shallower the top-down approach, the more neutral it tends to be.  This allows very shallow top-down methodologies to be applied across different systems. 
     69Coarse-to-fine approaches have a tendency to be more neutral to a modeling system - the shallower the coarse-to-fine approach (that is to say, the coarser the concepts) the more neutral it tends to be.  This allows very shallow coarse-to-fine methodologies to be applied across different systems. 
    4370 
    44 Bottom-up approaches are (by definition) founded on a specific modeling system, and so bottom-up methodologies are generally confined to a single modeling system. 
     71Fine-to-coarse approaches are (by definition) founded on a specific modeling system, and so these methodologies are generally confined to a single modeling system. 
    4572 
    4673---- 
Home
About PCA
Reference Data Services
Projects
Workgroups