Lecture Requirement engineering Chapter 1 Introdution of software requirement

Lecture Requirement engineering Chapter 1 Introdution of software requirement. This chapter presents the following content Software life cycle process, what is requirement? Requirement engineering, types of requirements.

 Software Life Cycle Process  What is Requirement?  Requirement Engineering  Types of requirements  [1] Ralph R Young - The Requirements Engineering Handbook- 2004 Artech House, Inc  [2] Karl E Wiegers, Software requirement, Second Edition- Microsof t Press © 2003(ebook)  [3] Brian Berenbach, Daniel J Paulish, Juergen Kazmeier, Arnold Rudorfer - Software & Systems Requirements Engineering: In Practice- Mc GrawHill, 2009  [4] Ian Alexander, Ljerka Beus-Dukic – Discovering Requirements - John Wiley and Sons, Ltd., Publication  Systems development life cycle (SDLC) The series of steps used to mark the phases of development for an information system  The SDLC has a set of five fundamental phases: Planning Analysis Design Implementation Test  A phase = a series of steps, which rely upon techniquesthat produce deliverables 28/4/2014  Structured design Waterfall Parallel Development  RAD Phased Developmen Prototyping  RUP  Agile Development extreme programming (XP), Scrum Dynamic Systems Development Method (DSDM) 28/4/2014 28/4/2014 28/4/2014 28/4/2014 28/4/2014  Software requirements include four distinct levels: Business requirements User requirements Functional requirements Non-Functional requirements  Business requirements  User requirements  Functional requirements  Non-functional requirements  Represent high-level objectives of the organization or customer who requests the system  Come from the funding sponsor for a project, the acquiring customer, the manager  Describe why the organization is implementing the system—the objectives the organization hopes to achieve  record the business requirements in a vision and scope document, sometimes called a project charter or a market requirements document  Describe user goals or tasks that the users must be able to perform with the system  Valuable ways to represent user requirements include use cases, scenario descriptions, and event-response tables  An example of a use case: "Make a Reservation" using an airline, a rental car, or a hotel Web site  Specify the software functionality that the developers must build into the product to enable users to accomplish their tasks  Describe what the system should  What inputs the system should accept  What outputs the system should produce  What data the system should store other systems might use  What computations the system should perform  The timing and synchronization of the above  Example: The user shall be able to search either all of the initial set of databases or select a subset from it Every order shall be allocated a unique identifier (ORDER_ID) which the user shall be able to copy to the account’s permanent storage area 35 A requirement that is not functional  Include many different kinds of requirements: Performance requirements Design constraints (also called process requirements) Commercial constaints  Performance requirements characterize system properties such as expected performance, capacity, reliability, robustness, usability, etc reflecting: usability, efficiency, reliability, maintainability and reusability  Design constraints (also called process requirements)  providing constraints on how the system should be designed and built – related to development process, documentation, programming language, maintainability, etc Categories constraining the environment and technology of the system Platform (minimal requirements, OS, devices…) Technology to be used (language, DB, …)  Commercial constaints: Categories constraining the project plan and development methods Development process (methodology) to be used Cost and delivery date Often put in contract or project plan instead  Example: Any interaction between the user and the system should not exceed seconds Only direct managers can see personnel records of staff  Complete  Correct  Feasible  Necessary  Prioritized  Unambiguous  Verifiable  Requirement Specification is a description of how a system should behave or a description of system properties or attributes It can alternatively be a statement of “what” an application is expected to ... Software Life Cycle Process  What is Requirement?  Requirement Engineering  Types of requirements  [1] Ralph R Young - The Requirements Engineering Handbook- 2004 Artech House,... Wiegers, Software requirement, Second Edition- Microsof t Press © 2003(ebook)  [3] Brian Berenbach, Daniel J Paulish, Juergen Kazmeier, Arnold Rudorfer - Software & Systems Requirements Engineering: ... accepted  Software requirements include four distinct levels: Business requirements User requirements Functional requirements Non-Functional requirements  Business requirements  User requirements