1. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 1 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap The Meaning Of Requirements Shiva Vafadar

2. E-mail: Vafadar@aut.ac.ir 2 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap Reference  M.Jackson, “The meaning of requirements,” Annals of Software Engineering Special Issue on Software Requirements Engineering

3. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 3 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap Subjects Discussed in this paper  The Importance of Requirements  A Concept of Requirements  The Machine and the Environment  Shared Phenomena

4. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 4 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap  concerned with functional requirements  Requirements are located in environment, which is distinguished from the machine to be built  Explains a distinction between requirements and specifications  Requirements appropriate description needs an appropriate structure for our description which consider the distinction between: The machine and the environment Indicatives description and optative descriptions

5. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 5 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap The importance of Requirement  Failures reasons of systems: 1. relatively straightforward programming errors 2. mismatch between the designed behavior of the computer part of the system and the effects in the environment  The computer hardware may perform correctly, and the software may satisfy its specification; but the results are not what was intended, and maybe disastrous Errors in system requirements engineering req. of the systems are  not correctly identified  Imprecisely expressed  based on faulty reasoning about the env.  Based on faulty approximations to the reality of the phenomena and properties of the environment

6. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 6 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap Shared Phenomena  The machine can affect, and be affected by, the environment only because they have some shared phenomena in common (events and states)  distinguish between What is controlled by the machine What is controlled by the environment

7. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 7 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap Reqs and Env. Properties  Requirements Are in the Environment  Optative and Indicative  Why Env. Assertions Are Necessary  Requirements and Specifications  The Nature of a specification

8. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 8 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap Optative and Indicative  The full description of a requirement consists of at least two parts: We must describe the requirement itself We must also describe the given properties of the environment (indicative) guaranteed by the env. (environment assertions)

9. Shiva Vafadar E-mail: Vafadar@aut.ac.ir 9 آزمايشکاه سيستم های هوشمند (http://ce.aut.ac.ir/islab) Requirements Engineering : A Roadmap Description and the Env.  Formalization and Informal Environments  Ground Terms  Designations  The Use of Definition  The Discipline of Designation and Definition