D.3.3 ALGORITHMS FOR INCREMENTAL ... - SecureChange

cultural phenomena in the context where they exist. The study is mainly built on semistructured
interviews with a high degree of discussion completed with focus groups
meetings.
The objectives of the user study are twofold: a) gain in-depth understanding of the
change management process adopted in a real industrial setting, and b) investigate the
role that an approach to model and reason on requirements evolution (previously proposed
in [15]) can play in such process. The approach consists of a representation of
an evolving requirement model as a set of controllable and observable rules and a reasoning
technique based on two metrics called maximal belief and residual risk that
intuitively measure the usefulness of a model element (or a set of elements) after evolution.
As industrial setting we have considered the air traffic management (ATM) domain
for two main reasons. First, the ATM systems are complex and critical systems that
are going through significant structural, operational and cultural changes as planned by
the EU Single European Sky ATM Research(SESAR) Initiative [1]. Second, change
management is still an open issue in the ATM domain: the need of system engineering
techniques to support change management is well recognized [13]. For the user
study, we have focused on the change management process followed by Air Navigation
Service Providers to introduce at operational level a new decision supporting tool, the
AMAN. The AMAN suggests to the Air Traffic Controllers (ATCOs) an optimal arrival
sequence of aircrafts and provides support in establishing the optimal aircraft approach
route.
The user study has involved twelve participants of which four were requirement
analysts who form the research team while the other were ATM domain experts who
have been involved in the change management process to introduce the AMAN. It also
provided useful insights into the weaknesses and advantages of our approach to requirement
evolution’s modeling and reasoning. The user study demonstrated the usefulness
of the approach to requirements evolution in the change management process. The reasoning
supported by the approach to requirements evolution has been considered by the
ATM experts as a powerful decision-support tool that allows one to select the optimal
design which is resilient to future changes in a requirements model. Moreover, we have
learnt important lessons about the aspects to be taken to into account when a research
methodology is designed.
The paper is organized as follows. Section 2 presents the related work. Section 3
gives an overview of the approach to requirements evolution which has been validated
during the workshop. Section 4 presents the research methodology. Section 5 summarizes
the results of the user study while Section 6 presents the relevant findings and
concludes the paper.
2 Related Work
Several studies have been conducted to understand the challenging aspects of requirements
engineering. Curtis et al. [5] published the first significant field study exploring
how requirements and design decisions are made. Crucial issues reported by the participants
of the study were conflicting requirements and communication breakdowns.
2