Which of the following approaches begins with the identification of only a few important concepts and,based
on these, the design proceeds, spreading outward ‘radially’?
A.
Inside-out approach
B.
Bottom-up approach
C.
Mixed approach
D.
Top-down approach
Explanation:
Inside-out approach can be regarded as a particulartype of bottom-up approach. It begins with the
identification of only a few important
concepts and, based on these, the design proceeds, spreading outward ‘radially’. First the concepts nearest to
the initial concepts are
represented, and a user then moves towards those further away by means of ‘navigation’ through the
specification.
Answer C is incorrect. In a mixed approach, the designer decomposes the requirements into a number of
components, as in the
bottom-up approach, but not to the extent where allthe concepts are separated. At the same time, a skeleton
schema is defined containing
the main concepts of the application. This skeletonschema gives a unified view of the whole design and helps
the integration of schemas
developed separately. Then the designer examines separately these main concepts and can proceed with
gradual refinements following the
top-down approach or extending a portion with concepts that are not yet represented following the bottom-up
approach.
Answer B is incorrect. In a bottom-up approach, thepreliminary specifications are broken down into smaller
components so that each
component describes a basic fragment of the specifications. These components are then represented by
schemas, some of which may consist of single concepts. The schemas are later obtained to be integrated
together until a final schema is obtained. Answer Dis incorrect. In a top-down approach, a schema is created
through a series of successive refinements, starting from the first schema, which is gradually expanded by
using appropriate modifications that increase the detail of the various concepts. Moving from one level to
another, the schema is modified using some basic transformations called top-down transformation primitives.