Project: I and Dependency Essay examples

Submitted By vkas29
Words: 3002
Pages: 13

ABSTRACT: i* (pronounced "i star") or i* framework is a modeling language suitable for an early phase of system modeling in order to understand the problem domain. i* modeling language allows to model both as-is and to-be situations. It is an approach originally developed for modelling and reasoning about organizational environments and their information systems composed of heterogeneous actors with different, often competing, goals that depend on each other to undertake their tasks and achieve these goals. It covers both actor-oriented and Goal modeling. i* models answer the question WHO and WHY of a situation or problem at hand. In the current paper we will talk about the two modelling components of i *: Strategic Dependency model (SD) & Strategic Rationale model (SR). We will also specifically focus on how i* framework can be used to express Actors, Tasks, Resources, Goals and Soft goals and its usage in requirement engineering to understand the problem domain.
We will be analysing and reporting on two papers from the literature wherein i* modelling technique or framework have been used and used to model organisational requirements. In this journey there would also be comparisons with techniques being used for modelling functional requirements like UML and what gap the i* modelling fills in the context.
1 Introduction
In Software Engineering, it is well recognized that capturing requirements that truly reflect users’ needs is crucial to the success of a system development effort. A major obstacle to gettingthe requirements right is the difficulty in obtaining a deep enough understanding about the application domain. During the early stages of requirements engineering, it is often necessary to help users identify different ways in which technical system solutions can serve their needs. Current requirements models (For Example : UML) that describe an organizational environment only in terms of entities and activities do not capture the many concerns that users have about the implications of adopting one solution versus another. Information technology is no longer limited to automating business processes but is in fact can play a vital role in reshaping businesses or re-engineering existing processes [Hammer90] [Davenport90] [Venkatraman91]. A central tenet of re-engineering is the need to ask “Why?” questions [Hammer90]. Without a clear understanding of the rationales behind existing practices and structures, one could not easily decide w hat changes could be made to business processes. By discovering underlying reasons, one can more readily identify outdated practices, and replace them with information technology systems and work arrangements that reflect new realities.
I* modelling aims to tackle and represent the business needs and expectations in terms of dependencies and relationships the existing and intended change will have on the stakeholders and working procedures.
Next we will provide an overview of the i* Framework and talk about the components that help us in representing the dependencies and relationships.

2 i* Framework Overview

The framework is called i*, as it attempts to articulate a notion of “distributed intentionality”. It consists of two models: a Strategic Dependency (SD) model for describing a particular configuration of dependency relationships among organizational actors, and a Strategic Rationale (SR) model for describing the rationales that actors have about adopting one configuration or another. (Yu, 1995)
2.1 The Strategic Dependency (SD) Model

The Strategic Dependency (SD) model is a network of dependency relationships among actors (Yu, 1995) The meaning of a dependency is that a depender, by depending on someone else (the dependee) for something (the dependum), can accomplish some goal or objective that it would otherwise be unable to achieve (or not as well). If the dependum is not forthcoming from the dependee, the depender would suffer as a result, i.e., its attempt to accomplish the