Modeling Service-Level Requirements: a Constancy Perspective

IT service requirements offer a seemingly classic Requirements Engineering (RE) problem. But, when attempting to solve it with RE methods, we are faced with difficulties. RE methods encourage us to identify the functional and non-functional requirements of a service. Industrial service-management frameworks, however, use a different vocabulary. ITIL, one of the most prominent service-management frameworks, refers to service utilities and service warranties. In this paper, we propose a method for modeling warranties as a function of the service constancy expected by stakeholders and the threats to this constancy. We identify four kinds of warranties: express, implied, tacit and pending. We thereby seek to bridge the gap between service-management frameworks and RE methods and to improve the practice of service management in organizations

Ontological analysis of means-end links

The i* community has raised several main dialects and dozens of variations in the definition of the i* language. Differences may be found related not just to the representation of new concepts but to the very core of the i* language. In previous work we have tackled this issue mainly from a syntactic point of view, using metamodels and syntactic-based model interoperability frameworks. In this paper, we go one step beyond and consider the use of foundational ontologies in general, and UFO in particular, as a way to clarify the meaning of core i* constructs and as the basis to propose a normative definition. We focus here on one of the most characteristics i* constructs, namely means-end links.Postprint (published version