Enhanced Use Case Map Traversal Semantics Jason Kealey and Daniel Amyot SITE, University of Ottawa, Canada jkealey@shade.ca, damyot@site.uottawa.ca Abstract. The Use Case Map (UCM) notation enables the use of graph- ical scenarios to model grey-box views of a system’s operational require- ments and behaviour, in context. The scenario traversal mechanism is the most popular UCM analysis technique but its current tool support in UCMNav is limited and hard to use, and the high-coupling of its features makes it difficult to maintain and evolve. This paper presents major enhancements to the recent jUCMNav Eclipse plug-in consisting of a new scenario traversal semantics accompanied by enhanced trace transformations to Message Sequence Charts. In addition, this paper identifies a set of semantic variation points which lay the groundwork for notational clarifications and user-defined semantic profiles. 1 Introduction The Use Case Map (UCM) notation [5] is a part of the proposal for ITU-T’s User Requirements Notation (URN) [1, 10]. UCMs visually model operational sce- narios cutting through a system’s component structure, providing a high-level, grey-box view of system behaviour in context. Because of their visual nature and apparent simplicity, UCMs are quickly understood by many stakeholders. Furthermore, UCMs are useful in various development phases such as require- ments modelling and analysis, test case generation, performance modeling, and business process modelling, and this in numerous application domains 1 . Among the techniques used to analyze and transform UCM models, the sce- nario traversal mechanism is likely the most popular and best supported one. This mechanism essentially provides an operational semantics for UCMs based on an execution environment. By providing an initial context, called scenario def- inition, the traversal mechanism determines which scenario paths of the UCM model will be followed, until no progress is possible. There are many typical applications of such traversal semantics, including: – Model understanding and scenario visualization: complex UCM mod- els involve many paths and diagrams that invoke one another. The traversal can highlight which scenario paths are followed in a given context (e.g., see Figures 1 and 2). In addition, the traversed paths can be visualized in a lin- ear form, e.g. by transforming them to Message Sequence Charts (MSC) [9], hence avoiding the need to flip back and forth through many diagrams. 1 The UCM Virtual Library, http://www.UseCaseMaps.org/pub/, contains a collec- tion of over 140 papers and theses illustrating these topics.