A Rationale-based Model for Architecture Design Reasoning

4.2. The chosen research and validation methods
Table 4.2: Case Study Verification
Research Questions
Evidence Collected
1. Is design rationale important Statistical Results
in architecture development?
2. Is design rationale important
in system maintenance?
3. What is the current state of practice of
design rationale in the software industry?
4. How to improve the representation Evaluation Results
of design rationale in architecture development?
Expert Opinion
5. How to implement traceability between requirements, Demonstration / Implementation
architecture design elements and design rationale?
6. How to estimate change impacts using Demonstration / Implementation
architecture design elements and design rationale?
ture design. The resulting method characterises the relationship between design elements
and design rationales. A proof-of-concept tool set has been developed to accompany the
method and it overcomes the usability issues identified in Table 3.1. Using an empirical
study, this new method is compared with using the traditional design specifications to
examine their effectiveness in design reasoning. Domain experts are asked to evaluate
the two methods to determine whether design rationale could help them understand and
reason with the system design. The case study used in this research is an Electronic Fund
Transfer System (EFT) which processes inter-bank fund transfers for The People’s Bank
of China in Guangzhou (PBC-GZ). The system was in production between 1998 and May
2006. It was originally designed by the author who led a team of architects and designers
using traditional waterfall software development methodology. A rationale-based model is
reconstructed for the EFT system to capture the missing design rationale. Its validation
is reported in Chapter 7.
For questions 5 and 6, we resolve the problems using traceability and Bayesian Belief
Networks methods. Based on the case study examples, we demonstrate the applications
in both research questions.
The architecture design rationale models presented in this thesis are early conceptual
models to integrate design rationale into architecture development. As such, the research
settings are to test the feasibility of the research concepts, characterise the design rationale
problem and then propose methods to address the issues. The validity of the conceptual
models is therefore limited to demonstrating that such an approach is feasible and likely to
be useful. Like most software engineering research projects, the real success of this work
can only be tested and validated through its continuous applications and improvements
in industrial projects, which is beyond the scope of this thesis.
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