Requirements Engineering Overview

Requirements Engineering

• Elicitation Phase: Initial stage where user needs and expectations are gathered.
• Organization Phase: Collected requirements are structured and categorized for analysis.
• Analysis Phase: Organized requirements are examined for gaps, conflicts, and priorities.
• Specification Phase: Final stage where analyzed requirements are documented for implementation.
• User Requirements: Statements in natural language describing what the system should do from the user's perspective.
• Functional Requirements: Specific behaviors or functions that the system must perform detailing what the system should accomplish.
• Non-functional Requirements: Criteria that specify how a system performs a function including performance, usability, reliability, and security.

Requirements Gathering Techniques

• Sampling: Gathering data by selecting a representative subset of users or situations.
• Research and Site Visiting: Studying existing systems and environments where the new system will operate.
• Observation of Work Environment: Watching users interact with current systems in their natural settings.
• Questionnaires: Structured forms used to collect information from users about their needs and expectations.
• Interviews: Direct conversations with users to gather in-depth insights about their requirements and experiences.
• System Prototyping: Creating a preliminary version of the system to visualize and refine requirements through user feedback.
• Joint Requirement Planning: Collaborative approach where stakeholders discuss and agree on requirements.

Requirements Analysis Techniques

• Affinity Diagrams: Organizing ideas and requirements into groups based on their natural relationships.
• Cause and Effect Analysis: Identifying the root causes of problems and their effects on system requirements.
• Force-Field Analysis: Identifying and analyzing the forces that support or hinder a change or requirement.
• Pareto Diagram: A bar graph representing the frequency of problems or requirements, helping to prioritize them based on impact.
• Quality Function Deployment (QFD): A structured approach to ensuring that customer requirements are met throughout the design and development process.

Component-Based Software Engineering (CBSE)

• Component: A modular part of a system that encapsulates its contents and can be replaced independently within its environment.
• Interface: A defined set of operations that a component exposes to other components, allowing them to interact.
• Provided Interface: An interface that a component offers to other components, indicating the services it provides.
• Required Interface: An interface that a component needs from other components to function properly.
• Dependency: A relationship that indicates one component relies on another to perform its functions.
• Port: A specific point of interaction on a component where interfaces are provided or required.
• Component Diagram: A UML diagram illustrating the components of a system and their relationships, focusing on the system's architecture.

More Component-Based Concepts

• Node: A physical element that represents a computational resource in a system, such as a server or device.
• Artifact: A physical piece of information that is used or produced by a component, such as a file or database.
• Stereotype: A mechanism in UML that allows the extension of the vocabulary of UML by creating new types of modeling elements.
• Subsystem: A group of related components that work together to perform a specific function within a larger system.
• Connector: A link that facilitates communication between components, often represented as a line in a diagram.
• Deployment: The process of distributing and installing components in a specific environment or on specific nodes.

Software Architecture Concepts

• Architecture: The overall structure of a system, including its components, their relationships, and the principles guiding its design.
• Modularity: The degree to which a system's components can be separated and recombined, promoting flexibility and reusability.
• Encapsulation: The bundling of data and methods that operate on that data within a single unit (component), restricting access to some of the object's components.
• Service: A function or operation provided by a component that can be accessed through its interfaces.
• Behavior: The actions or operations that a component can perform, often defined by its interfaces.
• Collaboration: The interaction between components to achieve a common goal or functionality within the system.

Unified Modeling Language (UML)

• UML: A standardized modeling language used to specify, visualize, and document the artifacts of a software system.

Data Flow Diagrams (DFDs)

• Data Flow Diagram (DFD): A visual representation of how data moves through a system, illustrating the processes, data stores, and data flows between them.
• Level 0 DFD (Context Diagram): Provides a high-level overview of the system, showing a single process and its interactions with external entities.
• Level 1 DFD: Breaks down the main process from the Level 0 DFD into sub-processes, showing how data flows between them and external entities.
• Level 2 DFD: Further decomposes one of the sub-processes from the Level 1 DFD, illustrating specific tasks and their data flows.
• Process: A function or activity that transforms input data into output data within the system.
• Data Store: A repository where data is stored for later use.
• External Entity: An outside actor that interacts with the system.
• Data Flow: The movement of data between processes, data stores, and external entities.
• Sub-process: A smaller, more detailed process that is part of a larger process.
• Context Diagram: Another term for Level 0 DFD, providing a simplified view of the system.

This quiz covers the essential phases of requirements engineering including elicitation, organization, analysis, and specification. It also explores various requirements types, such as user, functional, and non-functional requirements, as well as techniques for gathering requirements like sampling and site visiting.