Requirement Engineering: Understanding Essential Software Requirements and Processes, Lecture notes of Software Engineering

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Software Requirement

Engineering

Requirement Engineering^ Lecture^ #^4

• (^) The essential software requirement
• (^) Requirements from the customer’s perspective
• (^) Good practices for requirements engineering
• (^) The business analyst

Conten

t

• (^) The Essential Software Requirement ▫ Requirement Engineering ▫ Sub-discipline of Requirement Engineering 🞄Requirements development and 🞄Requirement Management ▫ Requirement Engineering Process

Requirement Engineering

According to International Requirements Engineering Board (IREB):

• (^) Requirements engineering is a cooperative, iterative,

incremental process, aimed at guaranteeing that:

▫ All relevant requirements are known and understood with the necessary degree of refinement, ▫ The stakeholders involved come to a satisfactory agreement concerning the known requirements, ▫ All requirements have been documented as defined by the documentation guidelines or specification guidelines.

Requirement Engineering

• (^) Requirements engineering is the sub-discipline of systems engineering

and software engineering that encompasses all project activities

associated with understanding a product's necessary capabilities and

attributes. Includes both requirements development and requirements

management.

Sub-disciplines of Requirements Engineering

Figure: Sub-discipline of Software Requirements Engineering

Requirement Development

• (^) “The process of defining a project's scope, identifying user classes and

user representatives, and eliciting, analyzing, specifying, and validating

requirements. Its product is a set of documented requirements that

defines some portion of the product to be built.”

Requirement Development (Cont..)

• (^) Requirements development is subdivided into: ▫ Elicitation , ▫ A nalysis , ▫ Specification , and ▫ Validation.
• (^) These sub-disciplines encompass all the activities involved with exploring, evaluating, documenting, and confirming the requirements for a

Elicitation (Cont..)

• (^) The key actions of Elicitation process are: ▫ Identifying the product’s expected user classes and other stakeholders. ▫Understanding user tasks and goals and the business objectives with which those tasks align ▫ Learning about the environment in which the new product will be used. ▫Working with individuals who represent each user class to understand their functionality needs and their quality expectations.

Elicitation (Cont..)

• (^) Requirements elicitation typically takes either a usage-centric

or a product-centric approach.

• (^) The usage-centric strategy emphasizes understanding and

exploring user goals to derive the necessary system functionality.

• (^) The product-centric approach focuses on defining features that

you expect will lead to marketplace or business success.

Analysis (Cont..)

• (^) Following are the principal activities: ▫Analyzing theinformation received from users to distinguish their task goals from functional requirements, quality expectations, business rules, suggested solutions, and other information ▫ Decomposing high-level requirements into an appropriate level of detail ▫ Deriving functional requirements from other requirements information ▫ Understanding the relative importance of quality attributes

Analysis (Cont..)

• (^) Following are the principal activities: ▫Allocating requirementsto software components defined in thesystem architecture ▫ Negotiating implementation priorities ▫Identifying gaps in requirementsor unnecessary requirementsas they relate to the defined scope

Validation

• (^) “The process of evaluating a project deliverable to determine whether it satisfies customer needs. Often stated as "Are we building the right product?”
• (^) (Verification: “Are we building the product right?”)
• (^) Requirements validation confirms that you have the correct set of requirements information that will enable developers to build a solution that satisfies the business objectives.

Validation (Cont..)

• (^) The central activities are: ▫ Reviewing the documented requirements to correct any problems before the development group accepts them. ▫ Developing acceptance tests and criteria to confirm that a product based on the requirements would meet customer needs and achieve the business objectives.