• Skip to main content
  • Skip to after header navigation
  • Skip to site footer

Shaping Software

Enduring Ideas in the Realm of Software

  • About
  • Topics
  • Best Software Books
  • Archives
  • JD Meier.com

Systems Engineering ‘in the small’

Jun 22, 2008 by JD

In software engineering, you can think of two levels: micro-level and macro-level.  On the micro-level, this is systems engineering ‘in the small.’  On the macro-level, there’s systems engineering ‘in the large.’  The two levels are complimentary. In Scenarios, Stories, Use Cases: Through the Systems Development Life-Cycle, Ian F. Alexander and Neil Maiden write about systems engineering ‘in the small.’ 

Systems Engineering ‘In the small’ Activities

Alexander and Maiden identify the following systems engineering ‘in the small’ activities:

  • User Requirements Definition (URD)
  • System Requirements Definition (SRD)
  • System Design / Architecture (SD/A)
  • Preliminary Design (PD)
  • Detailed Design (DD)
  • Implementation (Imp)
  • Test and Integration (T&I)
  • Acceptance and Certification (A&C)

Systems Engineering ‘In the small’ Activities Explained

Alexander and Maiden explain the key systems engineering ‘in the small’ activities as follows:

  • User Requirements Definition (URD) – The process of finding out who the users are, what they do, and what their needs are.
  • System Requirements Definition (SRD) – The process of finding the constraints  that have to be applied to the system acquisition process to obtain a fit-for-purpose result.  The system constraints can include detailed functional behavior, legislation, regulations, standards, technical interfaces, environmental and physical.
  • System Design / Architecture (SD/A) – The overall shape of a compliant solution is worked out.  Principal subsystems are identified and their individual requirements flowed down and refined.
  • Preliminary Design (PD) – Carry out sufficient design to provide confidence that the flowed-down system requirements are achievable at subsystem level.  It often concludes with a Preliminary Design Review (PDR).
  • Detailed Design (DD) – Carry out sufficient design to support implementation.  It should provide confidence that subsystem flowed-down requirements will be met.  This activity should be concluded with a Critical Design Review (CDR).
  • Implementation (Imp) – Here the subsystem designs are implemented using the relevant technologies, and tested at subsystem level.  Testing should determine that flowed-down requirements have been met.
  • Test and Integration (T&I) – During this activity, the individual components come together for testing as an integrated whole.  Compliance with the user and system requirements should be demonstrated.
  • Acceptance and Certification (A&C) – This activity is when the user community or their representatives take a tested and integrated system and confirm that what has been built is indeed what was wanted.  In highly regulated and/or high-integrity applications, this will involve approval by the appropriate certifying bodies.

Key Take Aways

Here’s my key take aways:

  • ‘in the small’ activities is micro-level systems engineering whereas ‘in the large’ is macro-level systems engineering.
  • Systems engineering ‘in the small’ and systems engineering ‘in the large’ are complimentary.
  • Systems engineering ‘in the small’ activities fit within systems engineering ‘in the large’ activities and phases.
  • Systems engineering ‘in the small’ activities include: User Requirements Definition, System Requirements Definition , System Design/Architecture, Preliminary Design , Detailed Design , Implementation, Test and Integration , Acceptance and Certification

My Related Posts

  • Waterfall, In the Large, and In the Small
  • A Process for Generating a Software Process
  • Four Reasons Why Defining an Effective Software Process is Tough
Category: ProcessTag: Process

About JD

Previous Post:A Process for Generating a Software Process
Next Post:Systems Engineering ‘in the large’

Reader Interactions

Trackbacks

  1. » Systems Engineering ‘in the small’ A System Of A Down: What The World Is Saying About A System Of A Down says:
    Jun 22, 2008 at 10:52 pm

    […] Engineering ‘in the small’ Posted in June 22nd, 2008 by in Uncategorized Systems Engineering ‘in the small’ Preliminary Design (PD) – Carry out sufficient design to provide confidence that the flowed-down […]

  2. Systems Engineering ‘in the large’ says:
    Jun 22, 2008 at 10:52 pm

    […] Systems Engineering ‘in the small’ […]

  3. AGATADEV » Systems Engineering ‘in the small’ says:
    Jun 23, 2008 at 12:03 am

    […] Original post by JD […]

Sidebar

Recent Posts

  • What is ChatGPT?
  • Agile Performance Engineering
  • What is Cybersecurity?
  • Software Security Threats: A Comprehensive Guide
  • What is Software Security?

Popular Posts

Best Software Books of All Time
Best Practices for Project Management
Best Practices for Software Development
Customer-Connected Engineering
How To Frame Problems Better
How To Pitch Business Ideas Better
How To Structure Vision Scope Presentations
Intro to Lean Software Development
Lean Principles for Software Development
The Enterprise of the Future