Week 6 Requirements Engineering II (Specification)

What is Requirements Specification?

The process of writing down the user and system requirements in a requirements document

what are the key qualities of an Ideal Requirements Specification?

Clear Unambiguous Easy to understand Complete Consistent

what are the sections of a structured specification?

Description of the function specified Description of inputs and their source Description of outputs and their source Information needed for running the function Description of action to be taken Description of consequences or side-effects of the function

what are the problems of natural language?

Lack of clarity Ambiguity Context dependency

what is an entity relationship diagram (ERD)?

Techniques that identifies a system’s entities and the relationship between those entities

what are ERD entities?

people, places, items, events, concepts

what are ERD Attributes?

properties or descriptive qualities of an entity

What are ERD Relationships?

nks between different entities

What are Decisison Tables?

Technique for specifying complex if-then conditions

name some mathematical methods?

Recurrence relations Axiomatic definition Formal specifications Implicit equations Regular expressions

What are Mathematical methods?

Describes both static and dynamic aspects of the system

What is Requirements Validation?

The process of “checking that requirements actually define the system that the customer really wants” (Sommerville)

List the Requirements Validation Checks

Consistency checks, Completeness checks, Realism checks, Verifiability.

What is a consistence check?

Consistency checks: requirements should not conflict

What is a compleatness check?

Completeness checks: all functions and constraints need to be defined

What is a realism check?

Realism checks: make sure the requirements can be implemented

What is a Verifiability check?

Verifiability: requirements should always be written so that they are verifiable/testable

list 3 requirments validation techniques.

Requirements reviews, Prototyping, Test-case generation.

What is a Requirements reviews?

systematic analysis of requirements by a team of reviewers

what is prototyping?

Prototyping: an executable model of the system is demonstrated to users/customers

what is Test-case generation:

Test-case generation: derive tests for each of the requirements

What is requirements management?

The process of “understanding and controlling changes to system requirements”