A metrics definition framework for i*

Measuring is a central task in the any engineering discipline, and modelling is not an exception. The need for measuring properties over i* models arises in different contexts. We have analysed this need over i* models of organizations, projects, systems and architectures. As a result, we have proposed a framework which includes: (a) a metamodel of i* that defines the elements that build the model; (b) a framework for the definition of metrics; (c) a collection of metrics (currently under construction) of different nature built with the framework. In this work, we present these basic concepts and discuss the applicability of the approach.Peer ReviewedPostprint (published version

Goal-driven agent-oriented software processes

The quality of software processes is acknowledged as a critical factor for delivering quality software systems. Any initiative for improving the quality of software processes requires their explicit representation and management. A current representational metaphor for systems is agent orientation, which has become one of the recently recognized engineering paradigms. In this article, we argue for the convenience of representing the software process using an agent-oriented language to model it and a goal-driven procedure to design it. Particularly we propose using the i* framework which is both an agent- and a goal-oriented modeling language. We review the possibilities of i* as a software process modeling language, and we also show how success factors can be made explicit in i* representations of the software processes. Finally, we illustrate the approach with an example based on the development of a set of ergonomic and safety software tools.Peer ReviewedPostprint (published version

A comparative analisys of i*-based agent-oriented modeling languages

Agent-oriented models are frequently used in disciplines such as requirements engineering and organizational process modelling. i* is currently one of the most widespread notations used for this purpose. Due to its strategic nature, instead of a single definition, there exist several versions and variants, often not totally defined and even contradictory. In this paper we present a comparative study of the three most widespread i* variants: Eric Yu’s seminal proposal, the Goal-oriented Requirement Language (GRL) and the language used in the TROPOS method. Next, we propose a generic conceptual model to be used as reference framework of these three variants and we show its use for generating specific models for the three mentioned variants, as well as for other existing proposals.Peer ReviewedPostprint (author’s final draft

On the use of i* for architecting hybrid systems: a method and an evaluation report

The architectural definition of hybrid software systems is a challenging problem that demands to reconcile stakeholders’ strategic needs and components marketplace, whilst defining an appropriate set of services. We have defined a method called DHARMA based on the i* framework. The goal of this paper is to present an experience report about the use of i* in large-scale projects. We provide two different viewpoints: the viewpoint of the stakeholder and the viewpoint of the modeller. Apart from general lessons learned, we also provide some insights about the use of i* in the specific context of architecting hybrid systems using DHARMA.Peer ReviewedPostprint (author’s final draft

Towards a framework for improving goal-oriented requirement models quality

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 ReviewedPostprint (published version

Towards interoperability of i* models using iStarML

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.Preprin

A family of experiments to evaluate the understandability of TRiStar and i* for modeling Teleo-Reactive systems

The Teleo-Reactive approach facilitates reactive system development without losing sight of the system goals. Objective: To introduce TRiStar as an extension of i* notation to specify Teleo-Reactive systems. To evaluate whether the notational extension is an improvement in terms of effectiveness and efficiency over the original language when it is used to specify Teleo-Reactive systems. Method: A family of experiments was carried out with final-year engineering students and experienced software development professionals in which the participants were asked to fill in a form designed to evaluate the efficiency and effectiveness of each of the languages. Results: Both the statistical results of the experiments, analyzed separately, and the meta-analysis of the experiments as a whole, allow us to conclude that TRiStar notation is more effective and efficient than i* as a requirements specification language for modeling Teleo-Reactive systems. Conclusion: The extensions made on i* have led to TRiStar definition, a more effective and efficient goal-oriented notation than the original i* language.This work was partially supported by the insPIre (ref. TIN2012-34003), cDrone (ref. TIN2013- 45920-R) and ViSelTR (ref. TIN2012-39279) projects of the Spanish Government. Also Spanish Ministerio de Educación, Cultura y Deporte, Subprograma Estatal de Movilidad, Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016 for grant CAS14/0023

Comparison of Business Motivation Model and Intentional Distribution

Eesmärkide modelleerimine on tähtis, et mõista erinevate tarkvara või arhitektuuri valikute tagamaid. Praegu leidub mitmeid eesmärkidele suunatud modelleerimise võtteid. Selles töös on kasutatud semiotic quality framework’i, et võrrelda Business Motivation Model’i (BMM) ja Intentional Distribution’i (i*) kvaliteeti üldistatud tasandil. Töös hinnatakse BMM-i ja i*-i keele kvaliteeti ja mudeli kvaliteeti. Lisaks kirjeldatakse kuidas BMM-i ja i*-i keeli saab kasutada äri protsessi mudeli, siin business processes model and notation, tegemisel.Goal modelling is an important activity to reason why different software decisions are taken, or architecture solutions are implemented. Currently there exist a number of goal-oriented modelling approaches. In this thesis, the semiotic quality framework is applied to compare the quality of the business motivation model (BMM) and Intentional Distribution (i*) modelling languages at the coarse-grained level. The thesis reports on the BMM and i* language quality and model quality. The thesis also presents observations on how the BMM and i* modelling languages could be used to reason on and support construction of the business process models expressed in business processes model and notation

3MSF: a framework to select mobile office devices

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 goal-oriented 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; and 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 ReviewedPostprint (published version

The notion of specialization in the i*framework

This thesis provides a formal proposal for the specialization relationship in the i* framework that allows its use in a well-defined manner. I root my proposal over existing works in different areas that are interested in representing knowledge: knowledge representation from Artificial Intelligence and conceptual modeling and object-oriented programming languages from Software Development. Also, I use the results of a survey conducted in the i* community that provides some insights about what i* modelers expect from specialization. As a consequence of this twofold analysis, I identify three specialization operations: extension, refinement and redefinition. For each of them, I: - motivate its need and provide some rationale; - distinguish the several cases that can occur in each operation; - define the elements involved in each of these cases and the correctness conditions that must be fulfilled; - demonstrate by induction the fulfilment of the conditions identified for preserving satisfaction; - provide some illustrative examples in the context of an exemplar about travel agencies and travelers. The specialization relationship is offered by the i* framework through the is-a construct defined over actors (a subactor is-a superactor) since it was first released. Although the overall meaning of this construct is highly intuitive, its effects at the level of intentional elements and dependencies are not always clear, hampering seriously its appropriate use. In order to be able to reason about correctness and satisfaction, I define previously the conditions that must be preserved when a specialization takes place. In addition, I provide a methodology with well-defined steps that contextualize the formal aspects of this thesis in a development process. As a conclusion, this thesis is making possible the use of the specialization relationship in i* in a precise, non-ambiguous manner