Specialization in the iStar2.0 language

iStar2.0 has been proposed as a standard language for building goal- and agent-oriented models. It is an evolution of the former i* language, with the purpose of homogenising existing syntactical and semantic variations of basic i* constructs that researchers in the field introduced along the years. In its first version (2016), iStar2.0 was intentionally kept simple, and some constructs were merely introduced but not formally defined. One of them is the notion of specialization. The specialization relationship is offered by iStar2.0 through the is-a construct defined over actors (subactor x is-a superactor y). Although the overall meaning of this construct is highly intuitive, its semantics when it comes to the fine-grained level of the models is not defined in the standard. In this paper we provide a formal definition of the specialization relationship ready to be incorporated into a next release of the iStar2.0 standard language. We root our proposal over existing work on conceptual modeling in general, and object-orientation in particular. Also, we use the results of a survey that provides some hints about what definition do iStar2.0 modelers expect from specialization. As a consequence of this twofold analysis, we identify, define and specify a set of specialization operations that can be applied over iStar2.0 models. Correctness conditions for them are also formally stated. The result of our work is a formal proposal of specialization for iStar2.0 that allows its use in a well-defined manner and contributes to its standardization.Peer ReviewedPostprint (published version

Using contextual goal models for constructing situational methods

Situation and intention are two fundamental notions in situational method engineering (SME). They are used to assess the context of an ISD project and to specify method requirements in this context. They also allow defining the goals of the method chunks and the conditions under which they can be applied. In this way, the selection and assembly of method chunks for a particular ISD project is driven by matching situational method requirements to method chunks’ goals and context descriptions. In this paper we propose the use of contextual goal models for supporting all SME steps. Our approach is based on iStar2.0 modeling language that we extend with contextual annotations.Peer ReviewedPostprint (author's final draft

Goal-oriented models for teaching and understanding data structures

Most computer science curricula include a compulsory course on data structures. Students are prone to memorise facts about data structures instead of understanding the essence of underlying concepts. This can be explained by the fact that learning the basics of each data structure, the difference with each other, and the adequacy of each of them to the most appropriate context of use, is far from trivial. This paper explores the idea of providing adequate levels of abstractions to describe data structures from an intentional point of view. Our hypothesis is that adopting a goal-oriented perspective could emphasise the main goals of each data structure, its qualities, and its relationships with the potential context of use. Following this hypothesis, in this paper we present the use of iStar2.0 to teach and understand data structures. We conducted a comparative quasi-experiment with undergraduate students to evaluate the effectiveness of the approach. Significant results show the great potential of goal modeling for teaching technical courses like data structures. We conclude this paper by reflecting on further teaching and conceptual modeling research to be conducted in this field.This work has been partially supported by the by the DOGO4ML Spanish research project (ref. PID2020-117191RB-I00), the Digitalization Initiative of the Canton of Zü-rich (DIZH), and ZHAW Digital.Peer ReviewedPostprint (author's final draft

Algebraic definition of iStar2.0 models

iStar2.0 was delivered in 2016 with the intention of becoming a standard de facto for the i* community. It includes a lightweight definition of the language adorned with a metamodel (in the form of a UML class diagram) that is useful for most purposes. However, in some contexts, a more precise algebraic definition including a notion of satisfaction is needed. This paper presents such elements. First, an algebraic definition of iStar2.0. Then, some auxiliary operations. Last, the notion of satisfaction over i* models using first order logic. Satisfaction is still defined mainly in a syntactic form, relying upon the satisfaction of the individual intentional elements comprising the model.Peer ReviewedPostprint (published version

Extending iStar2.0 metamodel to define data structures

iStar2.0 provides a recommendation for the core constructs defined in the i* language, which are articulated around a metamodel. When applying iStar2.0 to a particular domain, it can be necessary to extend this metamodel in order to represent more specialized concepts. One of these domains is that of data structures, as implementation of abstract data types. In this paper, we build upon previous work on using i* to describe data structures from an intentional point of view, by introducing new constructs in iStar2.0 and adding them to the iStar2.0 metamodel. We illustrate the approach using some well-known abstract data types (sequences, functions, …) and the data structures implementing them (linked lists, heaps, hash tables, …).Peer ReviewedPostprint (published version

Software analytics tools: an intentional view

Software analytic tools consume big amounts of data coming from either (or both) the software development process or the system usage and aggregate them into indicators which are rendered to different types of stakeholders, also offering them a portfolio of techniques and capabilities such as what-if analysis, prediction and alerts. Precisely, the variety of stakeholders and the different goals they pursue justifies the convenience of performing an intentional analysis of the use of software analytics tools. With this aim, we first enumerate the different stakeholders and identify their intentional relationships with software analytics tools in the form of dependencies. Then, we focus on one particular stakeholder, namely the requirements engineer, and identify further intentional elements represented in a strategic rationale model. The resulting model provides an abstract view of the domain which may help stakeholders when deciding on the adoption of software analytic tools in their particular context.This paper has been funded by the Spanish Ministerio de Ciencia e Innovación under project / funding scheme PID2020-117191RB-I00 / AEI/10.13039/501100011033.Peer ReviewedPostprint (published version

Using i* to describe data structures

This paper explores the use of the i* language as a notation to describe data structures to be used in classical imperative programs written in e.g. Java or C#. Data structures are described at two levels of abstraction, their specification and their implementation (the data structure properly said). We analyze how iStar 2.0, enriched with both modularization and dependum specialization constructs, can be used in this context.Peer ReviewedPostprint (published version

Goal-Oriented Requirements Engineering: State of the Art and Research Trend

The Goal-Oriented Requirements Engineering (GORE) is one approach that is widely used for the early stages of software development. This method continues to develop in the last three decades. In this paper, a literature study is conducted to determine the GORE state of the art. The study begins with a Systematic Literature Review (SLR) was conducted to determine the research trend in the last five years. This study reviewed 126 papers published from 2016 to 2020.  The research continues with the author's search for scientific articles about GORE. There are 26 authors who actively publish GORE research results. Twenty-six authors were grouped into seven groups based on their relation or co-authoring scientific articles. An in-depth study of each group resulted in a holistic mapping of GORE research.  Based on the analysis, it is known that most research focuses on improving GORE for an automated and reliable RE process, developing new models/frameworks/methods originating from GORE, and implementing GORE for the RE process. This paper contributes to a holistic mapping of the GORE approach. Through this study, it is known the various studies that are being carried out and research opportunities to increase automation in the entire RE process

Specialization in the iStar2.0 language

iStar2.0 has been proposed as a standard language for building goal- and agent-oriented models. It is an evolution of the former i* language, with the purpose of homogenising existing syntactical and semantic variations of basic i* constructs that researchers in the field introduced along the years. In its first version (2016), iStar2.0 was intentionally kept simple, and some constructs were merely introduced but not formally defined. One of them is the notion of specialization. The specialization relationship is offered by iStar2.0 through the is-a construct defined over actors (subactor x is-a superactor y). Although the overall meaning of this construct is highly intuitive, its semantics when it comes to the fine-grained level of the models is not defined in the standard. In this paper we provide a formal definition of the specialization relationship ready to be incorporated into a next release of the iStar2.0 standard language. We root our proposal over existing work on conceptual modeling in general, and object-orientation in particular. Also, we use the results of a survey that provides some hints about what definition do iStar2.0 modelers expect from specialization. As a consequence of this twofold analysis, we identify, define and specify a set of specialization operations that can be applied over iStar2.0 models. Correctness conditions for them are also formally stated. The result of our work is a formal proposal of specialization for iStar2.0 that allows its use in a well-defined manner and contributes to its standardization.Peer Reviewe