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The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-39417-6, i* is a widespread framework in the software engineering field that supports goal-oriented modeling of socio-technical systems and organizations. At its heart lies a language offering concepts such as actor, dependency, goal and decomposition. i* models resemble a network of interconnected, autonomous, collaborative and dependable strategic actors. Around this language, several analysis techniques have emerged, e.g. goal satisfaction analysis and metrics computation. In this work, we present a consolidated version of the i* language based on the most adopted versions of the language. We define the main constructs of the language and we articulate them in the form of a metamodel. Then, we implement this version and a concrete technique, goal satisfaction analys is based on goal propagation, using ADOxx. Throughout the chapter, we used an example based on open source software adoption to illustrate the concepts and test the implementation., Peer Reviewed, Postprint (author's final draft)

iStarML is an XML-based format for enabling interoperability among i* tools. Its main design focus was to support data interchange even when involved tools implement different i* variants. In this paper we analyse required changes to the format from two main sources (i) the evolution of i* into a consistent and clear set of core concepts expressed in the new iStar 2.0 specification and (ii) recurrent necessities due to a wide use of i* modelling. In order to address these requirements, we propose new XML elements to be considered in a new version of iStarML: iStarML2.0, Peer Reviewed, Postprint (published version)

Peer Reviewed, Postprint (published version)

Agent-oriented models are frequently used in disciplines such as agent-oriented requirements engineering, requirements engineering and organizational process modelling. i* is currently one of the most widespread notations used for this purpose. Due to both its dissemination and its highly strategic nature, instead of a single definition, several groups have formulated different variants, which define in a slightly different way the basic concepts of the language, as well as propose particular constructs that fit into the particular interests of these groups. In this chapter we first review these proposals and then we present a reference model that establishes the concepts and relationships that are fundamental in i*. The reference model is expressed as a UML class diagram (with OCL constraints) together with a vocabulary of the presented terms. Most of the included concepts are common to the seminal i* proposal, the GRL and the diverse variations used in the context of the Tropos methodology. For those concepts that are not shared by these analysed variants, the reference model tries to reconcile the different views whenever possible. The reference model allows determining the differences of any existing i* variant with respect to the model, and also to know how much different a new variant would be from the core of i*. The variants can be expressed by applying some refactoring operations on the UML class diagram. We illustrate this situation by applying refactoring to some of the analysed proposals., Postprint (published version)

Goal-oriented and agent-oriented modelling provides an effective approach to the understanding of distributed information systems that need to operate in open, heterogeneous and evolving environments. Frameworks, firstly introduced more than ten years ago, have been extended along language variants, analysis methods and CASE tools, posing language semantics and tool interoperability issues. Among them, the i* framework is one the most widespread. We focus on i*-based modelling languages and tools and on the problem of supporting model exchange between them. In this paper, we introduce the i* interoperability problem and derive an XML interchange format, called iStarML, as a practical solution to this problem. We first discuss the main requirements for its definition, then we characterise the core concepts of i* and we detail the tags and options of the interchange format. We complete the presentation of iStarML showing some possible applications. Finally, a survey on the i* community perception about iStarML is included for assessment purposes., Preprint

Goal-orientation is a widespread and useful approach to Requirements Engineering. However, quality assessment frameworks focused on goal-oriented processes are either limited or remain on the theoretical side. Requirements quality initiatives range from simple metrics applicable to requirements documents, to general-purpose quality frameworks that include syntactic, semantic and pragmatic concerns. In some recent works, we have proposed a metrics framework for goal-oriented models, but the approach did not cover the cycle of quality assessment. In this paper we present a semiotic-based quality assessment proposal built upon the i* framework and the SEQUAL proposal. We propose a simplification of SEQUAL which can be applied to i* models by defining semantic, pragmatic and social metrics. As a result, we obtain suites of metrics that can be applied to i* goal-oriented requirements models. This theoretical work is put into practice by using iStarML, a XML representation of i* models, over which XQuery sentences compute the proposed metrics., Peer Reviewed, Postprint (published version)

The mobile office devices market is currently growing, mainly due to the descending cost of wireless technology as well as the high diversity of functions and features covered. Diversity and proliferation become a hard problem when a person or organization aims at selecting the appropriate device for their particular needs. We propose here a framework for producing device recommendations based on personal or business needs. The framework is articulated through an architecture that includes subsystems for data extraction, recommendation and personalization. All these subsystems operate upon a goaloriented knowledge base whose presentation is the subject of this paper. Our approach is built upon three independent models: a market model, which contains descriptions of the current devices offered in the marketplace; a domain model, which states the needs of the person or organization; a mediator model, which describes the types of devices available. We show the actors and processes around these models. Last, we present a prototype that acts as proof-of-concept of the recommender system., Peer Reviewed, Postprint (author’s final draft)