Design

Definition

Design

the activity consisting of the cohesive collection of all tasks involving all aspects of producing and maintaining the tactical design of a system or an application

Classification

As illustrated in the preceding figure, Design is part of the following inheritance hierarchy:

• Type: Abstract
• Superclass: Activity
• Subclasses:
  • Business Design:
  • Component Design:
    • Data Component Design
    • Software Component Design
    • Hardware Component Design
  • Database Design
  • Design Pattern Production
  • Human Interface Design:
    • Website Design
    • Webpage Design

Responsibilities

The typical responsibilities of Design are to:

• Produce, document, and maintain the detailed tactical structure and behavior of an application's components.
• Determine the logical structure of the data component in terms of data types and the relationships between them.
• Maximize the quality of the design of the data components:
  • In terms of correctness, completeness, consistency, and understandability.
  • To meet the requirements (operational, informational, and quality).
  • To meet the design constraints.
  • To conform to the architectures.
• Maximize the productivity of the design teams (e.g., reuse of existing designs, reuse of design conventions, and existence of example documents).

Preconditions

Design typically may begin when the following preconditions hold:

• The initiation phase has started.
• The software development team is initially staffed and adequately trained in design.
• The user interface team is initially staffed and adequately trained in design.
• The following documents are largely complete and are relatively stable:
  • Requirements Documents:
    • Application Vision Statement
    • Requirements Executive Summary
    • System Requirements Specification
    • External API Specification
    • Glossary
    • Domain Model Document
  • Architecture Documents:
    • System Architecture Document
    • Information Architecture Document
    • Software Architecture Document

Completion Criteria

Design is typically complete when the following postconditions hold:

• The designs(s) have been documented.
• The deliverable work products in the design work product set have:
  • Passed evaluation.
  • Been accepted by the customer.
  • Been delivered to the customer.

Tasks

Design typically involves the following producers performing the following design tasks in an iterative, incremental, parallel and time-boxed manner:

• Database Team, which performs data component design:
  • Design Reuse
  • Design Prototyping
  • Design Production
  • Design Refactoring
  • Design Documentation
• Hardware Development Team, which performs hardware component design:
  • Design Reuse
  • Design Prototyping
  • Design Production
  • Design Refactoring
  • Design Documentation
• Software Development Team, which performs software component design and and data component design:
  • Design Reuse
  • Design Prototyping
  • Design Production
  • Design Refactoring
  • Design Documentation
• User Experience Team, which performs human interface design including website design and webpage design:
  • Design Reuse
  • Design Prototyping
  • Design Production
  • Design Refactoring
  • Design Documentation

Environments

Design is typically performed using the following environment(s) and associated tools:

• Engineering Environment:
  • Whiteboards
  • Word processing tool
  • Modeling tools

Work Products

Design typically results in the production of all or part of the following design work products:

• Diagrams:
  • Aggregation Diagram
  • Class Diagram
  • Collaboration Diagram
  • Data Design Diagram
  • Inheritance Diagram
  • Sequence Diagram
  • State Transition Diagram
• Documentation:
  • Class Responsibility Collaborator Card
  • Database Design Document
  • Hardware Design Document
  • Human Interface Design Document
  • Javadoc
  • Software Design Document
• Prototypes:
  • Hardware Component Prototype
  • Human Interface Prototype
  • Software Component Prototype

Phases

Design tasks are typically performed during individual phases as documented in the following table:

Guidelines

• This activity is documented using the typical configuration for large projects. It is intended to be configured (i.e., instantiated, extended, and tailored) to meet the needs of specific projects.
• The preconditions of this activity should be the union of the preconditions of its constituent tasks.
• The completion criteria for this activity should be the union of the postconditions of its constituent tasks.
• When designing websites, follow the website design guidelines.