“A ‘Physics’ of Notations”?Ideas of Daniel L. Moody

Presented byJ. David AndrewsPh.D. Candidate

School of Computing

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Main Reference

• The “Physics” of Notations: Toward a Scientific Basis for Constructing Visual Notations

Software Engineering, IEEE Transactions On Software Engineering, VOL. 35, NO. 6, November/December 2009

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UML

• UML as a communication medium.• Strongly visual at top level.• Two Medium/Large scale projects that used

UML (Rational).– One poorly.– One well.

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Poor Use• UML used as document production system.• Communication to non-developers:– Used Rational Rose as documentation system– For MIL-STD paper documentation.

• Communication to developers.– Ill-conceived class hierarchy.– Forced OO on objects ill-suited for it.

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I’m not even written in an OO Language!

Hello up there! We the classes need to be redesigned.

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Good Use

• Good communication to non-technical people.– Use cases.– Rapid prototypes.– Etc.

• Well conceived UML diagrams.• Not infected with ‘UML fever’. Death by UML

Fever, ALEX E. BELL, THE BOEING COMPANY’.

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My Initial Reaction

• Quite negative.• In the ‘good old days’ …– Fetzer: Program Verification: The Very Idea,

Communications of the ACM, Volume 31 Issue 9, Sept. 1988, Pages 1048 - 1063 – What some readers thought he said: “software

verification is worthless”.– What Fetzer said, “however much software

verification one does, the hardware is still subject to failure.”

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Physics?

• Let’s ask a physicist.

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Pseudoscience.

But good pseudoscience.

And needed pseudoscience.

Physics here is a metaphor.

For a systematic theory of picture-based communication.

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Semiotics/Ontology

• Huh?• Signs

• Reality

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What do signs give us?

• By themselves?• Not much …

• Used intelligently?• More, obviously …• But how much more?

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Towards

• Moody is saying:– We aren’t there yet.– But we want to be.– And here are some ideas to consider.

• Ideas often best formulated by …– People we tend to dismiss as pseudoscientists.

• So I’ll let Moody speak. In his own pictures.

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• Focus:

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• Visual Dialects

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• Ontological Analysis

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Essential for good communication.

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• Communication

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Color left out of UML for political correctness.

But why should ‘color’ be rendered by color?

Or ‘texture’ by visual texture?

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Solution Space

Principles

Extensible solution

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Perceptual Discrimination

• Visual Distance• Shape (prime importance).• Redundant Coding• Perceptual Popout• Textual Discrimination

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Semiotic Clarity

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Semantic Transparency

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Manageable Complexity

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Cognitive Integration

For example:

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Visual Expressiveness

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Dual Coding Text and Graphics

…

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Graphic Economy

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Cognitive Fit

For different kinds of users

With different skill levels.

Etc.

Images from Wikipedia

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Thank you!

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