Informatisches Kolloquium Sommersemester 2007

Montag, 21. Mai 2007

Prof. Dr. Anne De Roeck
Department of Computing
Faculty of Mathematics & Computing
The Open University
Milton Keynes
United Kingdom

Managing Harmful Ambiguity in Requirements

Requirements documents are typically written in some version of Natural Language. Natural Language is inherently ambiguous, and this creates misunderstandings between different stakeholders in the system, when different people make different assumptions about the interpretation of the requirements. At best, these misunderstandings lead to system problems that are expensive to rectify; at worst, in safety critical systems, they can be fatal.

Our work seeks to reduce the occurrence of ambiguity problems by developing tools that alert requirements engineers to parts of the documents that are likely to be misunderstood. This is a new approach to ambiguity management because it does not try to disambiguate. Instead, we develop a model of harmful, or "nocuous" ambiguity as a property of the relationship between a text and a group of people interpreting it. Nocuous ambiguity is defined as those cases where different people hold different interpretations.

I will describe a collection of experiments focusing on co-ordination ambiguity. We extracted interpretations from a collection of judges, and showed that nocuous ambiguity does occur the interpretation of requirements. We then developed a collection of heuristics, whose combined predictive power enabled us to identify, for our dataset, where differences in interpretation are likely to arise. This talk will set out the basic approach and our data, look at the heuristics, and their mode of combination, in some detail, and will then explain our evaluation regime.

Kontakt

Prof. Dr. Walther von Hahn
Telefon: 2434