Global Musical Tempo Transformations using Case Based ... - OFAI

Retrieve Pick earlier solved problems from the case base, that are similar
to the problem to be solved currently.
Reuse Adapt (or construct) an initial solution for the current problem,
based on the solutions of the retrieved problems.
Revise Test the proposed solution for adequacy (typically by user feedback)
and if necessary revise the solution to meet the requirements.
Retain Store the problem, together with its revised solution, in the case
base for future use.
Figure 3.3 shows how the four CBR tasks are organized within the problem
solving process. For generating a solution, a CBR system needs must at least
provide methods for the Retrieve and Reuse tasks. The Revise and Retain
tasks are necessary for storing proposed and corrected solutions as cases in
the case base, thus enabling learning.
After a subsection about the representation of cases in CBR systems,
which is an implicit but very important aspect of CBR, each of the four
tasks will be treated more in detail.
3.3.1 Case Representation
An important aspect of CBR system design is the representation of the cases.
In the first place the representation of information in the cases constrains
the way in which cases in the case base can be used in the various CBR
tasks. A case could be as simple as a vector of attribute-value pairs comprising
information about the problem and the solution (which is a common
representation in Nearest Neighbor Learning, see page 30). This kind of representation
is called a flat representation. In most CBR systems however, a
case contains extra information in addition to the problem description and
the solution, that specifies for example the dependencies of certain aspects
of the solution on certain features of the problem description, or how the
solution was obtained. The latter touches on another aspect of case representation,
that is closely related to the methods used for the Reuse task
(see section 3.3.3). That is the question whether a case should contain the
outcome of the reasoning process (the solution), or rather a problem solving
trace, (that is, a description of how the solution was obtained), or a combination
of solution and trace. Such traces may offer hints on how the solution
can be constructed for the input problem.
Besides the question how the cases should be represented, an important issue
is the representation/organization of the case base as a whole. Especially
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