Abstract:
Changes occur dynamically during the software application life time specif-
ically in service based applications (SBA) which are highly in
uenced by the
end-user. Such changes must be accommodated by updating the software
speci cation. To do this, often manual intervention of human user (referring
to a resource from the software development team) is needed, which increases
the maintenance cost. Self-Adaptive Systems (SAS) provide solution to re-
duce the complexity and costly maintenance while operating in an uncertain
and dynamically changing environment. To ensure this, SAS must be made
available with the runtime representation of its requirements and operations
to evolve its speci cation continuously in response to changes. A lot of work
has been done in recent years on service based applications in order to fa-
cilitate the end-users with run time service selection, thus making them self
adaptive. However, these works do not suggest any framework through which
the applications evolve themselves based on the end-user requirements. In
this thesis, a Requirements Driven Reasoning (RDR) framework is proposed
that solves the problem of evolving a Requirements Model of SAS at run-
time. The proposed framework uses a Requirements Model in which domain
speci c model is represented using Adaptive Requirements Modeling Lan-
guage (ARML) notations. Requirements re nement operators (de ned by
using the concepts in RE-Core ontology)such as adding, deleting and sus-
pending a requirement are also proposed for SAS to revise its Requirements
Model at runtime. The real-time working and the overall performance of
the framework is demonstrated here through an implemented restaurant ap-
plication as an exemplar case study. The data collected by monitoring the
case study scenarios behind the RDR framework has been used in compar-
ing their performance w.r.t the total throughput of the number of executed
requirements per scenario. The consistency of the Requirements Model has
been evaluated by tracing the adaptation in the design-time requirements.
