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The Australian National University

Informal Tutorial Notes - Wednesday 1500-1700

Week 2 - Systems Thinking

Predicting behaviour

Web-based SD tool

Using SD to understand software development processes

The effect of delay

The OODA loop

Gaining insights in complex networks

Week 3 - Systems Engineering

SAGE Air Defence System
  • 8-12 billion in 1964 dollars !!
  • Jay Forrester from MIT
  • MIT were the contracted System integrators
  • Wide area network - influence led to ARPANET and then the INTERNET
SAGE and Lincon Labs, MIT

Engineering Apollo: The Moon Project as a Complex System

  • MIT Open Course Ware
A handbook of Software and Systems Engineering

Processes and life-cycles are all well and good, but this book can help you understand the value of such things and select those processes which will add real value to your projects. Some example laws and hypotheses from the book:

Requirements
  • Glass' Law - Requirement deficiences are the prime source of project failures.
  • Boehm's Law - Prototyping (significantly) reduces requirement and design errors, especially for user interfaces.
  • Davis' Law - The value of a model depends on the view taken, but none is best for all purposes
  • Booch's Hypothesis - Object model reduces communication problems between analysts and users.
System design and specification
  • Curtis' Law - Good designs require deep application domain knowledge.
  • Simon's law - Hierarchical structures reduce complexity
  • Parnas' Law - Only what is hidden can be changed without risk
  • Booch's Hypothesis - Object-oriented designs reduce errors and encourage reuse.
System construction and composition
  • DeRemer's Law - What applies to small systems does not apply to large ones.
  • Dijkstra-Mills-Wirth Law - Well-structured programs have fewer errors and are easier to maintain.
  • Basili-Boehm COTS Hypothesis - COTS-based software does not eliminate the key development risks
Validation and static verification
  • Fagan's Law - Inspections significantly increase productivity, quality, and project stability.
  • May's Hypothesis - Error prevention is better than error removal.
Testing or Dynamic verification
  • Dijkstra's Law - Testing can show the presence but not the absence of errors
  • Pareto-Zipf-type Law - Approximately 80 percent of defects come from 20 percent of modules.
  • Nielsen-Norman Law - Usability is quantifiable.
  • Hamlet's Hypothesis - Suspicion-based testing can be more effective than most other approaches.
System administration
  • Lehman's law - An evolving system increases its complexity unless work is done to reduce it
  • Lehman's Law - System evolution is determined by a feedback process.
  • Basili'Moller Law - Smaller changes have a higher error density than large ones.
  • Wilde's Hypothesis - Object-oriented programs are difficult to maintain.
Project management and business analysis
  • Sackman's Law - Individual developer performance varies considerably.
  • Humphrey's law - Mature processes and personal discipline enhance planning, increase productivity, and reduce errors.
  • Brooks' law - Adding manpower to a late project makes it later
MIL-STD-499A Engineering Management - 1974

Lots can be learned from the past

  • developed to assist Government and contractor personnel in defining the system engineering effort in support of defense acquisition programs
  • Only 17 pages
  • tailoring
  • requires minimal documentation
CrossTalk Systems Engineering Society of Australia
  • a Technical Society of Engineers Australia
  • SETE / APCOSE 2012 Joint Conference, 30th April - 2nd May 2012, Brisbane Convention & Exhibition Centre
  • Student registration $185 - include 1 year membership of SESA

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