Requirements Engineering for Self-Adaptive Systems: Core Ontology and Problem Statement - Advanced Information Systems Engineering - page 35

We see runtime adaptation as a dynamic RE problem , where changes in requirements,
context, and resources lead to a new requirements problem, and this in turn requires the
resolution of that new problem. The dynamic aspect is that move from one requirements
problem formulation to another due to the changes that the SAS can detect. The problem
of reformulating the requirements problem when changes occur, and then solving the
changed problem is what we call the Runtime requirements adaptation problem .To
resolve this problem, we argue that it is necessary to know what kinds of information
and which relations are crucial for the system to capture. We therefore make explicit the
dynamic parts in the requirements problem formulation based on the CORE ontology.

4 RE for SAS and Its Core Ontology

Building upon the above considerations, we argue that concepts such as user's context
and resources must be considered as first class citizens on top of the existing CORE
ontology to engineer requirements for SAS. We add two new concepts, Context and
Resource on top of the CORE ontology to accommodate the changes that might occur
at runtime, which not only demands adaptation (i.e. dynamically changing from one
requirements problem to another) but also requires an update to the specification (i.e.
refinement of requirements).

Context (c)

Domain assumption (k)

Functional goal (g)

Relegate

Depend-on

Goal Is-a Quality constraint (q)

Communicated
information

Is-a

Softgoal (s)

Task (t)

Refer-to

Influence

Evaluation

Resource (r)

Is-a

Comparative evaluation
(“Preference” in Techne)

Individual evaluation

Is-optional relation
(Techne)

Is-a

Is-mandatory
relation (Techne)

Fig. 1. Revised ontology with new concepts ( Context and Resource ) and relations ( Relegation
and Influence ) related to the concepts of the CORE ontology for RE (for details, see [7])

The revised ontology of the concepts is proposed taking into account the concepts
proposed in Techne [8] to support the definition of runtime requirements adaptation
problem .InFig.1,concepts( Context and Resource ) and relations ( Relegation and
Influence ) are presented, relating them to the concepts of the CORE ontology. Below,
we start by introducing the concept of a requirements database.