Abstract

The environment in which a software system is developed is in a constant state of flux. The changes at higher levels of software development often manifest themselves in changes at lower levels, especially its activities and artifacts. In the past decade, a notable change has been the emergence of agile methodologies for software development.

In a number of agile methodologies, user stories have been adopted as a style of expressing software requirements. This thesis is about theory and practice of describing user stories so as to make them amenable to both humans and machines. In that regard, relevant concerns in describing user stories must be considered and treated separately.

In this thesis, a number of concerns in describing user stories are identified, and a collection of conceptual models to help create an understanding of those concerns are formulated. In particular, conceptual models for user story description, stakeholders, information, representation, and presentation are proposed.

To facilitate structured descriptions of user stories, a User Story Markup Language (USML) is specified. USML depends on the requisite conceptual models for theoretical foundation. It is informed by experiential knowledge, especially conventions, guidelines, patterns, principles, recommended practices, and standards in markup language engineering. In doing so, USML aims to make the decisions underlying its development explicit.

USML provides conformance criteria that include validation against multiple schema documents. In particular, USML is equipped with a grammar-based schema document and a rule-based schema document that constrain USML instance documents in different ways.

USML aims to be flexible and extensible. In particular, USML enables a variety of user story forms, which allow a range of user story descriptions. USML instance documents can be intermixed with markup fragments of other languages, presented on conventional user agents, and organized and manipulated in different ways. USML can also be extended in a number of ways to accommodate the needs of those user story stakeholders who wish to personalize the language.