Visualizing Systems

Visualizing Systems
An overview of the options

© Tim Sheiner, all rights reserved

A system is an interconnected set
of elements that is coherently
organized in a way that achieves
something.
Donella Meadows, Thinking in Systems


Show me a picture


Concept Structure

Dynamics

Behavior


Visualizing System Behavior


Graphs
๏ Most standardized system visual
➡ Used to present recorded data
➡ Taught in schools, used (and abused) by large number of disciplines
➡ Lots of software tools available for drawing these
๏ Several roughly synonymous names
➡ graph
➡ chart
➡ plot
๏ Abstracted, non-representational view
➡ Many types: line, bar, dot, spider, etc.
➡ All based on cartesian system (x vs y)


Line Graph Conventions
axis Plot of y=x title
5

y (units)

dependent
variable

axis
0 7
Origin x (units)
independent variable

Complex Example

This is actually 3
graphs displayed on
top of each other: 2
line charts and 1 bar
2 y-axes chart

key


Independent Variable not always Time

In drug
development an
important
relationship is the
response
(dependent
variable) or
outcome that occurs
for a given dose
(independent
variable) of a drug

Dose vs Response

Simple plots are never “true”

best “fit” This graph actually
displays a great
recorded value
deal of qualifying
information
uncertainty


System response is probabilistic
Probable Response at Dose log10-4
Progesterone (M)

50

40

% Inhibition

30


Visualizing System Dynamics


Flow Diagrams
๏ Represent system dynamics in a static form
๏ Some standardized conventions
➡ standard generic flow chart conventions
➡ detailed standards for engineering flow disciplines like electronics
➡ attempts at standardization for systems theory
๏ Range from representational to schematic


Generic Flow Chart Conventions
Start A

Process Step 1 Process Step 2

Process Step 2
No
Decision

End
Yes

A
“I’ve run out of space, find a similar symbol
elsewhere in drawing to continue flow”

Example of Electronics Conventions


Heating Dynamics Representationally

Decision

Signal

Heat


Heating Dynamics as Stocks & Flows

An existing standard
for representing flow
in classical system
thinking literature.
Difficult to parse?


Heating Dynamics as Flow Schematic
Feedback: Classic Example
Thermostat regulating room temperature
(via a heater)
Desired temperature e.g. 68º . . is indicated by adjusting the
.
Alternative
temperature control lever

external
electrical source
. . . sends current to. . .
which in turn moves the bi-metal coil;
increasing the desired temperature
moves the coil closer to the contact point;
representation of
decreasing the desired temperature
moves the coil further from the contact point thermostat system by
Dubberly & Pangaro.

output
input

Bi-metal coil. . .bends to touch the. . . . Contact point . . . . which sends a signal to the. .Heater
.
(as it cools)

. . .bends the opposite . . . . thus no signal is sent,
is measured by

can increase
direction to lose and the heater shuts off
contact with the. . .
(as it warms)

System

air temperature in the room

Why does a bi-metal coil bend?
lowers the

bi-metal coils consist of two layers of metal
(usually iron and copper)
joined together to form one flat strip;
because the metals have different coefficients
of expansion, the strip will bend
in one direction as it cools, and the opposite
direction as it warms Cold air outside

January 2010 | Developed by Paul Pangaro and Dubberly Design Ofﬁce 41


Generic Flow Schematic
Feedback: Formal Mechanism
Goal . . . describes a relationship
that a system desires to have Combines flow and

is embodied in
with its environment

concept map
conventions and is
reasonably easy to

output
input

a Sensor passes the current state value to a Comparator . . . . . . . . . . responds by driving an Actuator
‘read.’
. . . has subtracts . . . has
resolution – (Accuracy) the current state value resolution
is measured by

frequency – (Latency) from frequency
A better standard for

affects the
range – (Capacity) the desired state value range
to determine
the error

System systems flow
Environment visualizations?
can affect the

Disturbances . . . may be characterized as certain types
typically falling within a known range;
but previously unseen types may emerge
and values may vary beyond a known range;
in such cases the system will fail
because it does not have requisite variety
January 2010 | Developed by Paul Pangaro and Dubberly Design Ofﬁce 39


Visualizing System Structure


Illustrations
๏ Used to explain behavior or method of construction
๏ Very standardized in some contexts
➡ Mechanical Engineering
➡ Architecture
๏ Must be representational to be useful
➡ Representation challenging for abstract systems
➡ With abstract systems, illustrations of structure and flow diagrams
hard to distinguish from one another


Standardized in Physical Disciplines


Some Abstract Standardizations Exist

UML is an example of
a standard for
abstract systems that
has some degree of
penetration among
object oriented
programmers and
system architects.


Ad Hoc Structure for Abstract Systems
Current state of the art for
illustrating the structure of an
abstract system involves simple
symbols, shapes, arrows &
annotation


Visualizing System Concepts


Concept Maps
๏ Used to communicate mental models
๏ Present ideas and relationships
➡ Rely on text not symbols
➡ Use arrows to communicate relationships not flow
๏ Not at all representational


Concept Map Conventions

Concept Map

nodes representing concepts
is a

with
that explain the
graph relating relationships
between
with

linking lines that have linking words

redrawn from http://redie.uabc.mx/contenido//vol2no1/art-11-eng/contenido-ruiz-figura1.png

Concept Map Examples


Animating System Visuals


Animated System Visualizations
๏ Static pictures are inherently limited in their ability to
explain dynamic systems
๏ Animated presentations can provide a richer
communication experience
➡ can use audio
➡ can use time
➡ can use feedback
๏ Animated presentations are systems in themselves
➡ computer simulations
➡ keyframes animations & videos
➡ prototypes
➡ new forms of content


System Simulations

Most system
simulation tools are
too complex and
proprietary for
common use, but
simpler, web-based
tools are being
developed.


Keyframe Animations & Video

Click-thru mockups
are a powerful form a
system visualization.
They can be converted
to videos to simulate
the experience of
interacting with the
system.


Interactive Prototype

An interactive
prototype is a tool for
creating a mental
model in a person’s
mind of a system that
does not yet exist.


New forms of content

Documents combining
interactivity, words
and sounds may
eventually become a
common way to
explain systems.

Watch: http://www.ted.com/talks/mike_matas.html

System Visualization Conclusions
๏ Static pictures of systems are compact and portable
๏ The right picture to produce depends upon what
aspect of a system you want to communicate or
understand
➡ Behavior = Graphs
➡ Dynamics = Flow Diagrams
➡ Structure = Illustrations
➡ Concepts = Concept Maps
๏ Animated system visualizations convey more
information than static presentations and may
ultimately become the standard for describing
systems

Visualizing Systems

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