In this thesis we present the requirements engineering discipline and in particular goal-oriented modelling languages. They are mostly used to help the stakeholders to express their needs. During the requirements engineering process, these needs are transformed into goals. Then these goals will be themselves transformed into requirements that will be fulfilled by the future system. To facilitate the communication between users and developers, system modellers often use diagrams to graphically represent goals and requirements. They use this technique because it is commonly accepted that graphical representations are easier to understand than formal sentences. However, it is not as trivial as it looks. To be effective, diagrams have to be drawn following specific rules described in a graphical language evaluation theory called the Physics of Notation. If not, the risk is that they will become so complex that they fail to reach their aim. We analyse in particular one goal modelling approach called KAOS. Then, we apply the principles for an effective communication which is measured by the speed, ease and accuracy with which the information content is understood. Following these principles the KAOS visual notation is evaluated, and finally we give some recommendations to improve it. These recommendations will be of 3 types: for novice users, for users that draw diagrams during a meeting and for software developers who are building a tool that implements KAOS. Our recommendations are validated in a running example that consists of an online bookshop store. Our work leads to improvements to the KAOS visual notation to create more effective goal models.
Improving the gognitive effectiveness of the KAOS requirements modelling language
Dupriez, M. (Author). 2011
Student thesis: Master types › Master in Computer science