Software Development Prototypes and UML Diagrams

Requirements Engineering in the Software Process

• Software projects require determining a system's goals before construction.
• Agile projects (e.g., Scrum) have goals at varying levels (sprint goals).
• Requirements engineering (RE) is a collaborative process ensuring:
  • All relevant requirements are known and understood adequately.
  • All requirements are documented appropriately.
  • Stakeholders agree on the known requirements.
• RE is an iterative process occurring throughout the project, not just at the start.
• Stakeholders include all those affected or involved in system creation and use.
• RE aims to reflect and develop shared knowledge and understanding among the team.
• Requirements serve communication, identifying optimization potential, and customer benefit, informing tendering/contracting, software design, testing, integration/maintenance, and increasing satisfaction.

Core Activities in Requirements Engineering

• RE core activities involve determining and documenting requirements, as well as their reconciliation.
• Requirements are generated or imposed in many areas of companies.
• Project failures often stem from insufficient requirements analysis.

Requirements Documentation

• Documentation ensures a shared understanding among stakeholders and is useful for:
  • Communication
  • Knowledge retention for future use/maintenance
• Documentation is crucial during disputes.
• Different stakeholders require different levels of detail and documentation.

What is a Requirement?

• Requirements are solutions to problems.
• Three main types of requirements include:
  • Functional: describing system behavior
  • Quality: detailing attributes like response time
  • Constraints: limiting the solution space.

Determination of Requirements Sources

• Analyze the surrounding systems and stakeholders.
• Identify various sources for requirements:
  • Stakeholders (documents, policies, other systems)
• Select appropriate elicitation techniques.
• Elicit requirements using selected techniques.
• Define system context.

Determination of Requirements Using Techniques

• Requirements are systematically determined.
• Tools like checklists and questionnaires assist.
• Requirements are identified, formulated, checked, and evaluated.
• Factor costs and experience of the technique are assessed when considering its usefulness.

Investigative Techniques

• Interviewing: verbal interviews, questionnaires
• Creative: brainstorming, perspective changes, analogy technique, 6-3-5 method
• Documentation-centered: analyzing existing documents, system archaeology
• Observation: field observation, apprenticing
• Experiments: prototyping, simulations, UX testing, concept tests

Forms of Documentation

• Requirements are documented using a combination of text and tables.
• Four essential elements often include:
  1. Project overview/vision
  2. High-level overview of the system
  3. Detailed requirements
  4. Glossary (definitions of relevant terms)

System Modeling UML

• UML (Unified Modeling Language) provides a set of notation elements for building static and dynamic models of analysis, design, and architecture.
• UML diagrams are used to document a system's functional aspects.
• Relevant UML diagram types for documenting systems include class diagrams, use case diagrams, and activity diagrams.

Checking and Reconciling Requirements

• Evaluating requirements for implementation is critical. Early identification and resolution of errors are vital, as propagated errors can affect the project negatively.
• Processes focus on establishing consensus on requirements with review criteria.
• Conflict resolution may involve negotiation or alternative strategies like postponing the solution, or designating it as not important for the project.
• Documentation ensures appropriate and complete analysis.

Managing Requirements and Prioritization

• Requirements engineering emphasizes understanding stakeholders’ experience, prioritizing requirements for effective use and implementation.
• Requirements should have clear properties (identification, description, and stability, among others) for successful tracing and management.
• Techniques exist to prioritize requirements (e.g., MOSCOW method and value-risk matrix).
• Categorization of requirements aids in understanding and managing.