=Paper=
{{Paper
|id=Vol-1674/iStar16_pp7-12
|storemode=property
|title=A Proposed Textual Model for i-Star
|pdfUrl=https://ceur-ws.org/Vol-1674/iStar16_pp7-12.pdf
|volume=Vol-1674
|authors=Fabio Penha,Marcia Lucena,Leonardo Lucena,Celso Agra,Fernanda Alencar
|dblpUrl=https://dblp.org/rec/conf/istar/PenhaLLAA16
}}
==A Proposed Textual Model for i-Star==
https://ceur-ws.org/Vol-1674/iStar16_pp7-12.pdf
A Proposed Textual Model for i-Star
Fabio Penha1, Marcia Lucena2, Leonardo Lucena1, Celso Angra3, Fernanda Alencar34
1
Instituto Federal do Rio Grande do Norte (IFRN), Natal, Brasil
2
Universidade Federal do Rio Grande do Norte (UFRN), Natal, Brasil
3
Universidade de Pernambuco (UPE), Recife, Brasil
4
Universidade Federal de Pernambuco, (UFPE), Recife, Brasil
{fabio.penha, leonardo.lucena}@ifrn.edu.br,
marciaj@dimap.ufrn.br, celso.agra@gmail.com,
fernanda.ralencar@ufpe.br
Abstract. Despite software engineering community efforts, projects continue to
fail. Researches have shown that modeling became more critical due to the
growth of complexity and scale of the system. In this context, the i* Frame-
work, a Goal-oriented Requirement Language, is used to model and analyze
dependencies and intentions relationships of actors on the observed environ-
ment. However, in large-scale projects, i* graphical notation makes the model
more complex due to lack of scalability and some ambiguous representations.
This paper shows a proposed textual model as a complementary vision of the i*
models. Its main objective is achieving a modeling approach that combines text
and graphic to i* Framework. We discuss how this proposal can help to miti-
gate scalability and complexity problems.
1 Introduction
Computational systems are present everywhere in society, playing a crucial role in
various human activities. Therefore, complex social-technical systems require pro-
cesses, methods, techniques and tools to capture, verify and inspect models that repre-
sent this abstracted reality. Despite the efforts of the software engineering community,
project’s failure rate continues an alarming growth. Therefore, the business process
modeling became much more critical, since these systems expand in scale and com-
plexity [1]. Thus, besides analyzing static and dynamic aspects, it is also necessary to
consider social and intentional aspects [2]. In this context, the i* framework is a mod-
eling language used to develop models that represent the needs of the involved actors
[2]. The i* language has been used in several situations [2], such as telecommunica-
tions, air traffic control, agriculture, e-government, healthcare and business process.
Nevertheless, it is inadequate for modeling very complex systems or systems that
involve many actors [10]. The scalability of i* is only one among its main obstacles to
be used industrially [2] [10].
Some researchers have shown that graphical languages can be more intuitive than
textual languages. However, both of then bring individual benefits to be evaluated
Copyright © 2016 for this paper by its authors. Copying permitted for private and academic purposes.
Proceedings of the Ninth International i* Workshop (iStar 2016), CEUR Vol-1674
when they are used together. Moreover, experience has shown that it is much harder
to deal with graphic languages, especially when they need to be stricter and formal [4]
[5]. Thus, we propose a textual model for the i* Framework with the aim of making it
an approach that combines textual and graphical representations, improving its ad-
vantages because we are able to achieve the following benefits through this textual
model: languages integration, platform independence, versioning, formatting quality,
code generators and translators [13] [6]. There is a textual model called iStarML,
which differs from the proposal of this work regarding the intentionality. iStarML is
an XML-based Interchange Format conceived to work with interoperability between
tools and meta [14], while the textual model presented in this work is an alternative
for modeling the i*, which may interest those people who are more familiar with
codes or even facilitate the reading/interaction of domain expertise once it would
allow us to express the system in a language closer to natural language.
This paper is structured into the following sections: Section 2 presents the con-
struction of the textual model regarding both graphical and textual visions. Besides,
some discussions about the proposal are also presented. Finally, in section 3, we pre-
sent conclusions and a future work.
2 Textual Model for i-Star
Although the recent efforts and progress that have been made in the i* scientific
community in the search for a single metamodel [8] [11], there is no consensus yet.
For this reason and due to the fact of the metamodel represents only the conceptual
elements, we developed the metamodel of the Fig. 1, based on [12], that focus on
extracting the elements from the Strategic Dependency (SD) Model and the Strategic
Rationale (SR) Model. The intention is to allow that other model can be granted based
solely on the i* notation. This metamodel cannot fail to follow the premise that the i*
framework is an actor-centered approach. Yu [2] emphasizes this concept to say that
the analysis focuses on (i) how well the goals of various actors are achieved, given
some configuration of relationships between human and system actors, and (ii) what
reconfigurations of those relationships can help actors advance their strategic inter-
ests.
Fig. 1. The i* Metamodel, adapted from [12]
8
A Proposed Textual Model for i-Star
The semantic understanding of i* Framework enables researchers to best
understand the relationship among i* elements. This knowledge helped us depict a
metamodel where the actor is framed by three elements: (i) The
ActorAssociationLink defines the relationship among actors, indicating the organiza-
tional structure. (ii) The DependencyRelationship represents dependency relations of
the actor through an intentional element. Semantically, there is the perspective of the
depender and another of the dependee on the intentional element. (iii) The
IntencionalElement describes an internal relationship of the actors with the inten-
tional elements; an actor consists of intentional elements. The proposed textual model
is shown through transformations from the graphical model [7] to textual model. Fig.
2, shows a graphic model being represented textually. It was used two actors (Project
Manager and Software Management Professional) to illustrate the transformation,
in which the actor may contain or not an ActorAssociationLink references other ac-
tors.
Fig. 2. Definition of Actor and their structural relationships (textual and graphic)
The transformation presented in Fig. 3 describes the external relationship of an ac-
tor (Costumer - depender) that depends on another actor (Call Phone Service Pro-
vider - dependee) to perform a task (Register For New Service - dependum). This
transformation shows the relationship was defined in two perspectives: the depender
perspective and the dependee perspective. Note that when this dependency relation-
ship is described in two perspectives (depender and dependee), there is a decouple in
the actor modeling, i.e., everything expected to know about the actor is described in a
single actor file The syntax of external relationship element complies with the inten-
tional element (dependum), there is a specific syntax for external relationships for
each association with a dependum kind (goal, softgoal, task, and resource) (Tab 1).
Fig. 3. Definition of an external relationship
9
Proceedings of the Ninth International i* Workshop (iStar 2016), CEUR Vol-1674
A single file describes all external and internal relationships of the actor on model-
ing, which makes it possible to define modeling as a set of files corresponding to
analyzed actors. Fig. 4 and Fig. 5 show a small transformation example of SR model
(Fig. 4) to a textual model (Fig. 5). Finally, it can be observed a complete textual
representation of an actor that presents us three section used in the actor's definition,
which are: DependencyRelationship, ActorAssociationLink and
IntencionalElement.
External Relationship Element (DependencyRelationship)
the Depender perspective Dependum the Dependee perspective
defines Task executes
wants Goal reaches
wishes Softgoal tries
needs Resource provides
Table 1. Dependency Relationship Syntax
Fig. 4. The graphic model
Fig. 5. single file describes all external and internal relationships of the actor
10
A Proposed Textual Model for i-Star
Although the proposal does not exclude the graphical models (SD and SR), it is
relevant to report that the textual model can answer the following questions [2]: (i)
What does each actor want? (ii) How do they achieve what they want? (iii) Who do
they depend on to achieve what they want? These questions are focused on the own i*
modeling concepts. There are benefits to be considered for the proposed model. Con-
cerning aspects of language, we have an extensible and scalable vision regarding
technical aspects such as version system and compilers.
A textual language for i* Framework is a model presenting a new perspective
without changing its essence and completes the existing models. In the proposal of
iStar 2.0 [8] have already discussed possible visions for the framework, such as the
actor view. Regarding extensibility, it is possible to create mechanisms to work with
textual languages, without change affecting the graphical models. E.g. using an ap-
proach to mark elements with tags, we could generate contextualized graphical mod-
els, such as @AccountabilityDep to mark all relationships that involve the Accounta-
bility Department. Some concepts of scalabilities are presented in [9]: (i) the capacity
to having models in different levels of abstraction, to facilitate for specialists and
developers to understand the general behavior of all system or focus in a specific part
of system, (ii) it is able to handle numerous Agents (actors) in an application. The
textual model can be divided into a set of units, or actors, and allows looking in a
specific actor at all. Besides, it provides all levels of abstractions and inserting actors
without a crucial impact.
Regarding the control version system and the collaborative development, this ap-
proach uses textual files. This facilitates the integration with tools for version control,
such as CVS1, Git 2 and SVN3 , that makes collaborative work easier. Besides, com-
pilers can be used to automatize the processes, as following: (i) change files / actors
(depender) related to an external relationship, to notify the needs to perform elements
internals; (ii) transform the model into another model; (iii) improve the modeling by
generating animation and simulation based on actor that will be a sequence (iv) cre-
ates mechanisms to perform a qualitative investigation of modeling, allowing an anal-
ysis that can help to reconfigure the modeling (i.e. detect if an actor is overloaded).
3 Conclusion and future work
This paper presented a metamodel composed only of the essence of the models
used in the i* framework, which allowed the creation of other proposed models with-
out abandoning the essence. With this metamodel, a textual approach to the i* was
introduced. It was generated by transformation from graphical notation to textual one;
we have also proposed a discussion about the benefits of a textual model for i*
Framework.
1
http://www.nongnu.org/cvs/
2
https://git-scm.com/
3
https://subversion.apache.org/
11
Proceedings of the Ninth International i* Workshop (iStar 2016), CEUR Vol-1674
As a future work, we are developing a toolkit to support this model with automatic
mechanisms that performs qualitative and quantitative analysis modeling (i.e. compil-
ers), as well as, mechanisms to link both approaches (textual and graphical).
4 References
1. Joseph Barjis. 2008. The importance of business process modeling in software systems de-
sign.Sci. Comput. Program. 71, 1 (March 2008), 73-87.
2. Eric S. Yu. 2009. Social Modeling and i*. In Conceptual Modeling: Foundations and Ap-
plications, Alexander T. Borgida, Vinay K. Chaudhri, Paolo Giorgini, and Eric S. Yu
(Eds.). Lecture Notes In Computer Science, Vol. 5600. Springer-Verlag, Berlin, Heidel-
berg 99-121.
3. C. Nunes, J. Araújo, V. Amaral, and C. Silva, "A DOMAIN SPECIFIC LANGUAGE
FOR THE I* FRAMEWORK", 11th International Conference on Enterprise Information
Systems: Springer-Verlag, 04, 2009.
4. Luc Engelen and Mark van den Brand. 2010. Integrating Textual and Graphical Modelling
Languages. Electron. Notes Theor. Comput. Sci. 253, 7 (September 2010), 105-120.
5. D. Harel and B. Rumpe. 2000. Modeling Languages: Syntax, Semantics and all that Stuff,
Part I: the Basic Stuff. Technical Report. Weizmann Science Press of Israel, Jerusalem, Is-
rael, Israel.
6. Mazanec, M. and Macek O. On General-purpose Textual Modeling Languages. Proc. 12th
Annual International Workshop on Databases, Texts, Specifications, and Objects, Zernov,
Rovensko pod Troskami, Czech Republic, pp. 1–12, 2012
7. Istarwiki.org (2016) http://istar.rwth-aachen.de/tiki-view_articles.php
8. F. Dalpiaz, X. Franch and J. Horkoff, iStar 2.0 Language Guide, dblp computer science
bibliography, 2016 http://arxiv.org/abs/1605.07767v3
9. P. Lima, J. Vilela, E. Gonçalves, J. Pimentel, A. Holanda, J. Castro, F. Alencar, M.
Lencastre. Scalability of iStar: a Systematic Mapping Study. CIBSE - WER. 2016
10. X. Franch. The i* framework: the way ahead. In: sixth international conference on Re-
search Challenges in Information Science (RCIS), 2012. pp. 1–3.
11. Cares, C., Franch, X., López, L., & Marco, J.. (2010). Definition and Uses of the i*
Metamodel. ISTAR.
12. M. Lucena, E. Santos, C. Silva, F. Alencar, M. Silva, J. Castro, “Towards a Unified Meta-
model for i*,” RCIS 2008.
13. H. Gronniger, H. Krahn, B. Rumpe, M. Schindler, and S. Volkel. Textbased Modeling. In
4th International Workshop on Software Language Engineering, 2007.
14. Cares, C., Franch, X., Perini, A., Susi, A.: iStarML: An XML-based Model Interchange
Format for i*. In: Castro, J.B., Franch, X., Perini, A., Yu, E. (eds.) Proc. 3rd Int. i* Work-
shop, Recife, Brazil, February 11-12, 2008, vol. 322, pp. 13–16. CEUR Workshop Pro-
ceedings, CEUR-WS.org (2008)
12