Stéphane Faulkner

A core ontology for requirements

In their seminal paper ACM T. Softw. Eng. Methodol., 61 1997, 1--30, Zave and Jackson established a core ontology for Requirements Engineering RE and used it to formulate the “requirements problem”, thereby defining what it means to successfully complete RE. Starting from the premise that the stakeholders of the system-to-be communicate to the software engineer the information needed to perform RE, Zave and Jacksons ontology is shown to be incomplete, in that it does not cover all classes of basic concerns --namely, the beliefs, desires, intentions, and evaluations --that the stakeholders communicate. In response, we provide a new core ontology for requirements that covers these classes of basic stakeholder concerns. The proposed new core ontology leads to a new formulation of the requirements problem. We thereby establish a new framework for the information that needs to be elicited over the course of RE and new criteria for determining whether an RE problem has been successfully addressed.

A comprehensive quality model for service-oriented systems

In a service-oriented system, a quality (or Quality of Service) model is used (i) by service requesters to specify the expected quality levels of service delivery; (ii) by service providers to advertise quality levels that their services achieve; and (iii) by service composers when selecting among alternative services those that are to participate in a service composition. Expressive quality models are needed to let requesters specify quality expectations, providers advertise service qualities, and composers finely compare alternative services. Having observed many similarities between various quality models proposed in the literature, we review these and integrate them into a single quality model, called QVDP. We highlight the need for integration of priority and dependency information within any quality model for services and propose precise submodels for doing so. Our intention is for the proposed model to serve as a reference point for further developments in quality models for service-oriented systems. To this aim, we extend the part of the UML metamodel specialized for Quality of Service with QVDP concepts unavailable in UML.

A more expressive softgoal conceptualization for quality requirements analysis

Initial software quality requirements tend to be imprecise, subjective, idealistic, and context-specific. An extended characterization of the common Softgoal concept is proposed for representing and reasoning about such requirements during the early stages of the requirements engineering process. The types of information often implicitly contained in a Softgoal instance are highlighted to allow richer requirements to be obtained. On the basis of the revisited conceptual foundations, guidelines are suggested as to the techniques that need to be present in requirements modeling approaches that aim to employ the given Softgoal conceptualization.

SketchiXML: towards a multi-agent design tool for sketching user interfaces based on USIXML

During these last years, many researchers have proposed new alternatives for early interface design based on hand-sketch. But these new alternatives seem to be dedicated to obsolescence as they only offer the possibility to generate user interfaces for a single platform in a unique language. Indeed, in a context where the number of computing-platforms and system environments is exploding, new alternatives should be considered. This paper presents an innovating alternative with SketchiXML, a multi-agent application able to handle several kinds of hand-drawn sources as input, and to provide the corresponding specification in USIXML (USer Interface eXtensible Markup Language), a platform-independent user interface description language.

Clear justification of modeling decisions for goal-oriented requirements engineering

Representation and reasoning about goals of an information system unavoidably involve the transformation of unclear stakeholder requirements into an instance of a goal model. If the requirements engineer does not justify why one clear form of requirements is chosen over others, the subsequent modeling decisions cannot be justified either. If arguments for clarification and modeling decisions are instead explicit, justifiably appropriate instances of goal models can be constructed and additional analyses applied to discover richer sets of requirements. The paper proposes the “Goal Argumentation Method (GAM)” to fulfil three roles: (i) GAM guides argumentation and justification of modeling choices during the construction or critique of goal model instances; (ii) it enables the detection of deficient argumentation within goal model instances; and (iii) it provides practical techniques for the engineer to ensure that requirements appearing both in arguments and in model instance elements are clear.

Analysis of Multi-Party Agreement in Requirements Validation

A requirements engineering artifact is valid relative to the stakeholders of the system-to-be if they agree on the content of that artifact. Checking relative validity involves a discussion between the stakeholders and the requirements engineer. This paper proposes (I) a language for the representation of information exchanged in a discussion about the relative validity of an artifact; (ii) the acceptability condition, which, when it verifies in a discussion captured in the proposed language, signals that the relative validity holds for the discussed artifact and for the participants in the discussion; and (iii) reasoning procedures to automatically check the acceptability condition in a discussions captured by the proposed language.

Justifying Goal Models

Representation and reasoning about information system (IS) requirements is facilitated with the use of goal models to describe the desired and undesired IS behaviors. One difficulty in building and using goal models is in knowing why a model instance is as it is at some point of the requirements engineering (RE) process. If justifications for modeling choices are missing, an instance of a goal model can neither be considered appropriate nor inappropriate in a given RE project. This paper suggests a goal argumentation method (GAM) for recording the decision-making process which results in modeling choices. GAM combines a design rationale approach that guides common-sense reasoning about the goal model with an argumentation model which records and allows analysis of the justification processes leading to modeling decisions

An agent-oriented meta-model for enterprise modelling

This paper proposes an agent-oriented meta-model that provides rigorous concepts for conducting enterprise modelling. The aim is to allow analysts to produce an enterprise model that precisely captures the knowledge of an organization and of its business processes so that an agent-oriented requirements specification of the system-to-be and its operational corporate environment can be derived from it. To this end, the model identifies constructs that enable capturing the intrinsic characteristics of an agent system such as autonomy, intentionality, sociality, identity and boundary, or rational self-interest; an agent being an organizational actor and/or a software component. Such an approach of the concept of agent allows the analyst to have a holistic perspective integrating human and organizational aspects to gain better understanding of business system inner and outer modelling issues. The meta-model takes roots in both management theory and requirements engineering. It helps bridging the gap between enterprise and requirements models proposing an integrated framework, comprehensive and expressive to both managers and software (requirements) engineers.

What stakeholders will or will not say: A theoretical and empirical study of topic importance in Requirements Engineering elicitation interviews

Interviewing stakeholders is a way to elicit information about requirements for a system-to-be. A difficulty when preparing such elicitation interviews is to select the topics to discuss, so as to avoid missing important information. Stakeholders may spontaneously share information on some topics, but remain silent on others, unless asked explicitly. We propose the Elicitation Topic Map (ETM) to help engineers in preparing interviews. ETM is a diagram showing topics that may be discussed during interviews, and shows how likely stakeholders discuss each of these topics spontaneously. If a topic is less likely to be discussed spontaneously, then this suggests that engineers may want to prepare questions on it, before the interview. ETM was produced through theoretical and empirical research. The theoretical part consisted of identifying topic sets based on a conceptual model of communication context, grounded in philosophy, artificial intelligence, and computer science. The empirical part involved interviews with Requirements Engineering professionals to identify the topic sets and topics in each set, surveys of business people in order to evaluate how likely they would spontaneously share information about topics, and evaluations of how likely students would share information about each topic, when asked about requirements for social network websites.

Product portfolio scope optimization based on features and goals

In this paper we propose a mathematical program able to optimize the product portfolio scope of a software product line and sketch both a development and a release planning. Our model is based on the description of customer needs in terms of goals. We show that this model can be instantiated in several contexts such as a market customization strategy or a mass-customization strategy. It can deal with Software Product Line development from scratch as well as starting from a legacy software base. We demonstrate its applicability with an example based on a case study.