CHAPTER.2: Requirements Engineering Processes By: Dr. Wa’el Jumah AL-Zyadat Chapter-2

Requirements Engineering Processes OUTLINES: RE BASIC PROCESS. RE EVOLUTIONARY PROCESS. Chapter-2

Requirements Engineering Processes 1.0 - RE BASIC PROCESS. 1.1- RE Process: A Basic Framework. 1.2- RE Process: Spiral Model. 1.3- RE Processes: RAD (Role Actor Diagram). 1.4- IEEE Standard for SRS 1.6- RE in Agile Methods Requirements Engineering Processes  2.0 - RE EVOLUTIONARY PROCESS 2.1- RE Evolutionary Process. 2.2- RE in Software Lifecycle Chapter-2

Many variations and extensions 3 fundamental activities: 1.0 - RE BASIC PROCESS. 1.1- RE Process: A Basic Framework. Many variations and extensions 3 fundamental activities: Understand (formally) describe, Attain an agreement on, the Problem Chapter-2

1.1- RE Process: A Basic Framework. 1.0 - RE BASIC PROCESS. 1.1- RE Process: A Basic Framework. Elicitation: determine what’s really needed, why needed, whom to talk to Specification: produce a (formal) SRS model: translate "vague" into "concrete", etc. make various decisions on what & how Validation: assure that the SRS model satisfies the users’ needs As one of the processes in software engineering, Requirements Engineering (RE) plays a vital role in ensuring the overall success of the software engineering process. However, many of the substantial problems that the software industry faces today are still the same as the ones discovered during the software engineering crisis 36 years ago [Jiang, L. [2005] SRS: Software Requirements Specification  Chapter-2

1.2- RE Process: Spiral Model. 1.0 - RE BASIC PROCESS. 1.2- RE Process: Spiral Model. 3- Testable 1- Complete 2- Traceable: 4-Consistent 8- Using “Shall” and Related Words 4-Consistent 5- Feasible 6-Uniquely Identified 7- Design Free critical attributes: Chapter-2

1.2- RE Process: Spiral Model. 1.0 - RE BASIC PROCESS. 1.2- RE Process: Spiral Model. Requirements elicitation: Requirements discovered through consultation with stakeholders Requirements analysis and negotiation: Requirements are analyzed and conflicts resolved through negotiation Requirements documentation: A requirements document is produced Feasible Requirements validation: The requirements document is checked for consistency and completeness what the advantages of using Spiral Model ? what the disadvantages of using Spiral Model ? Chapter-2

1.3- RE Processes: RAD (Role Actor Diagram). . 1.0 - RE BASIC PROCESS. 1.3- RE Processes: RAD (Role Actor Diagram). . An RE Process is dominated by human, social and organizational factors Cont.. Chapter-2

“What is an actor?” Is now addressed 1.0 - RE BASIC PROCESS. 1.3- RE Processes: RAD (Role Actor Diagram). . “What is an actor?” Is now addressed UML defines actors as “a coherent set of roles that users of use cases play when interacting with these use cases. An actor has one role for each use case with which it communicates”. We have the following problem with this definition: all entities realize a set of roles. So what is so unique to the actor? To understand the specificity of the actors, we need to consider how they are used: Cont.. Chapter-2

An actor links use cases together by realizing a set of roles. 1.0 - RE BASIC PROCESS. 1.3- RE Processes: RAD (Role Actor Diagram). . An actor links use cases together by realizing a set of roles. An actor represents, in a use case diagram, an entity coming from another diagram (or vice-versa). Using the same name for an actor and an entity in another diagram establishes this relation An actor may have a generalization relationship with another actor. An actor represents entities that will not be further specified. Cont.. Chapter-2

1.0 - RE BASIC PROCESS. 1.4- IEEE Standard for SRS Chapter-2

1.0 - RE BASIC PROCESS. 1.4- IEEE Standard for SRS Chapter-2

1.0 - RE BASIC PROCESS. 1.4- RE in Agile Methods Chapter-2

2.1- RE Evolutionary Process Chapter-2

2.2- RE in Software Lifecycle RE EVOLUTIONARY PROCESS. 2.2- RE in Software Lifecycle an SDLC aims to produce high quality systems that meet or exceed customer expectations, based on customer requirements, by delivering systems which move through each clearly defined phase, within scheduled time-frames and cost estimates requirements definition: Defines project goals into defined functions and operation of the intended application. It is the process of gathering and interpreting facts, diagnosing problems and recommending improvements to the system. Analyzes end-user information needs and also removes any inconsistencies and incompleteness in these requirements. Chapter-2

2.2- RE in Software Lifecycle RE EVOLUTIONARY PROCESS. 2.2- RE in Software Lifecycle Chapter-2