UNIT 1 - REQUIREMENT ANALYSIS AND PROTOTYPING

Requirement

A condition or capability needed by a user, system, or system component to solve a problem, achieve an objective, or satisfy a formal specification.

Functional requirement

Specifies what the application or system should do; usually describes behavior that takes input and produces output.

Non-functional requirement

Defines how the system should perform, including quality attributes such as performance, maintainability, usability, and effectiveness.

Business requirements

High-level stakeholder requirements that describe the proposed system from the end-user perspective and define the business problem or need to be addressed.

Architectural and design requirements

Detailed requirements that determine the overall design needed to implement the business requirements.

System and integration requirements

Detailed requirements that describe the steps and functions needed to satisfy the business requirements; often written as detailed descriptions or user stories.

Sources of requirements

Interviews, knowledge transfer, ideas from analysts/managers/developers, observation of existing systems, previous requirement documents, enhancement/error reports, and domain or industry knowledge.

Requirement analysis

The process of analyzing users' and customers' needs to define software requirements and determine the actual needs of stakeholders.

Characteristics of requirement analysis

Has a specific goal, input, and output; uses resources; follows ordered activities; may affect multiple organizational units; and creates value for the customer.

Requirement engineering

The process of defining user expectations and determining, analyzing, documenting, validating, and managing requirements for a new or modified system.

Requirement analysis process

1) Eliciting requirements, 2) Analyzing requirements, 3) Requirements modeling, 4) Review and retrospective.

Main activities in requirement analysis

Identify customer needs, evaluate feasibility, perform economic and technical analysis, allocate functions, establish schedules and constraints, and create system definitions.

Stakeholder issues

Users may have unclear needs, avoid committing to written requirements, request changes late, communicate slowly, skip reviews, lack technical knowledge, or misunderstand the development process.

Engineer/developer issues

Developers may start coding too early, misunderstand users because of vocabulary differences, or force requirements to fit an existing system instead of the client's actual needs.

BPMN — Business Process Modeling Notation

A process-modeling technique used to graph business processes and show activities, roles, and required data.

UML — Unified Modeling Language

An integrated set of diagrams used to specify, visualize, construct, and document software systems, especially object-oriented systems.

Flowchart Technique

Shows the sequential flow and control logic of related activities and can represent data flows, system interactions, and parallel processes.

Data Flow Diagram (DFD)

Visually represents how information moves through a system, including inputs, outputs, processes, data stores, and entities.

Role Activity Diagram (RAD)

A role-oriented process model that shows organizational roles, responsibilities, activities, and coordination between activities.

Gantt Chart

A project-planning chart that shows scheduled tasks, timelines, and the start and end dates of project activities.

IDEF — Integrated Definition for Function Modeling

Represents process functions and their relationships to parent and child systems, helping with system analysis, design, and integration.

Workflow Technique

A visual representation of business processes used to understand workflows and recommend process improvements.

Object-Oriented Methods

Modeling methods that focus on identifying objects, their states, behaviors, and interactions to analyze and design systems.

Gap Analysis

Analyzes the difference between the current state and target state to determine whether business requirements are being met and what improvements are needed.