This document discusses concepts related to complexity theory and its relationship to software development. It covers topics like agents, landscapes, emergence, complexity, criticality, and connectedness. Examples are provided to illustrate concepts like traffic jams modeled as a complex system of simple interacting agents. Conway's Game of Life is presented as an example of emergence. Network theory basics are reviewed in the context of diffusion, robustness, and the relationship between networks and complexity. The document advocates applying principles of complexity theory like agent-based modeling to challenges in software development.

1. COMPLEXITY
THEORY SOFTWARE
DEVELOPMENT
and
by Tim Berglund
Monday, June 21, 2010

2. ACKNOWLEDGMENTS
Monday, June 21, 2010

3. ACKNOWLEDGMENTS
http://bit.ly/unde
rstanding-compl
exity
Monday, June 21, 2010

4. ACKNOWLEDGMENTS
http://bit.ly/unde
rstanding-compl
exity
Monday, June 21, 2010

5. ACKNOWLEDGMENTS
http://bit.ly/understanding-complexity
Monday, June 21, 2010

6. The Santa Fe Institute is a private, not-for-profit,
independent research and education center founded in 1984,
for multidisciplinary collaborations in the physical,
http://www.santafe.edu biological, computational, and social sciences.
Understanding of complex adaptive systems is critical to
addressing key environmental, technological, biological,
economic, and political challenges.
Renowned scientists and researchers come to Santa Fe
Institute from universities, government agencies, research
institutes, and private industry to collaborate in attempts to
uncover the mechanisms that underlie the deep simplicity
present in our complex world.
Monday, June 21, 2010

7. Agents
Landscapes
Emergence
Complexity
Criticality
Connectedness
Monday, June 21, 2010

8. Agents
Monday, June 21, 2010

9. Agents are...
Monday, June 21, 2010

10. Agents are...
Simple
Monday, June 21, 2010

11. Agents are...
Simple
Interactive
Monday, June 21, 2010

12. Agents are...
Simple
Interactive
Adaptive
Monday, June 21, 2010

13. Why Does
TRAFFIC
Jam?
Monday, June 21, 2010

14. Stuck
TRAFFIC
in
Monday, June 21, 2010

15. Stuck
in TRAFFIC
all this
space! I'm'a
speed up.
Monday, June 21, 2010

16. Stuck
TRAFFIC
in
Monday, June 21, 2010

17. Stuck
TRAFFIC
in
Talking on cell
phone, not paying
attention...
Monday, June 21, 2010

18. Stuck
TRAFFIC
in
Monday, June 21, 2010

19. Stuck
TRAFFIC
in
I sure am in
a hurry!
Monday, June 21, 2010

20. Stuck
TRAFFIC
in
Monday, June 21, 2010

21. Stuck
TRAFFIC
in
Monday, June 21, 2010

22. Stuck
TRAFFIC
in
maniAc!
Monday, June 21, 2010

23. Stuck
TRAFFIC
in
Monday, June 21, 2010

24. Stuck
TRAFFIC
in
Oh, my
bad.
Monday, June 21, 2010

25. Stuck
TRAFFIC
in
Monday, June 21, 2010

26. Stuck
TRAFFIC
in
@%$#%!
Monday, June 21, 2010

27. Gameof
Conway’s
LIFE
Monday, June 21, 2010

28. Gameof
Conway’s
LIFE
1. Any live cell with fewer than two live neighbors
dies.
2. Any live cell with more than three live neighbors
dies.
3. Any live cell with two or three live neighbors lives.
4. Any dead cell with exactly three live neighbors
comes to life.
Monday, June 21, 2010

29. Gameof
Conway’s
LIFE
Monday, June 21, 2010

30. Gameof
Conway’s
LIFE
Monday, June 21, 2010

31. Gameof
Conway’s
LIFE
Monday, June 21, 2010

32. Monday, June 21, 2010

33. Monday, June 21, 2010

34. Agents
Landscapes
Emergence
Complexity
Criticality
Connectedness
Monday, June 21, 2010

35. Landscapes
Monday, June 21, 2010

36. Monday, June 21, 2010

37. Think of a
Problem
as a
SURFACE
Monday, June 21, 2010

38. MT. FUJI
Monday, June 21, 2010

39. Monday, June 21, 2010

40. Frederick
Winslow
TAYLOR
Monday, June 21, 2010

41. RUGGED
LANDSCAPES
Monday, June 21, 2010

42. Dancing
LANDSCAPES
Monday, June 21, 2010

43. Monday, June 21, 2010

44. What’s the
Quickest Way to the
SUMMIT?
Monday, June 21, 2010

45. Monday, June 21, 2010

46. EXPLORATION vs.
EXPLOITATION
Monday, June 21, 2010

47. Agents
Landscapes
Emergence
Complexity
Criticality
Connectedness
Monday, June 21, 2010

48. Criticality
Monday, June 21, 2010

49. the Normal
DISTRIBUTION
Monday, June 21, 2010

50. the Central
LIMIT
Theorem
Monday, June 21, 2010

51. the Central
LIMIT
Theorem
“The mean value of a repeatedly
sampled random variable approaches a
normal distribution as the sample size
approaches infinity.”
Monday, June 21, 2010

52. the Central
LIMIT
Theorem
Monday, June 21, 2010

53. the Central
LIMIT
Theorem
“The world is pretty much a normal place.”
Monday, June 21, 2010

54. the Power Law
DISTRIBUTION
Monday, June 21, 2010

55. Monday, June 21, 2010
Rice PILES

56. Work
LOAD
Monday, June 21, 2010

57. Work
LOAD
Monday, June 21, 2010

58. Work
LOAD
Monday, June 21, 2010

59. Work
LOAD
Monday, June 21, 2010

60. Work
LOAD
Monday, June 21, 2010

61. Work
LOAD
Monday, June 21, 2010

62. Work
LOAD
Monday, June 21, 2010

63. Work
LOAD
Monday, June 21, 2010

64. Work
LOAD
Monday, June 21, 2010

65. Work
LOAD
Monday, June 21, 2010

66. Work
LOAD
Monday, June 21, 2010

67. Work
LOAD
Monday, June 21, 2010

68. Work
LOAD
Monday, June 21, 2010

69. Work
LOAD
Monday, June 21, 2010

70. Work
LOAD
Monday, June 21, 2010

71. Work
LOAD
Monday, June 21, 2010

72. Monday, June 21, 2010

73. Too much
Optimization leads to
CRITICALITY
Monday, June 21, 2010

74. Agents
Landscapes
Emergence
Complexity
Criticality
Connectedness
Monday, June 21, 2010

75. Connectedness
Monday, June 21, 2010

76. Monday, June 21, 2010

77. A really basic refresher in
Graph
THEORY
Monday, June 21, 2010

78. A really basic refresher in
Graph
THEORY Seriously...BASIC.
Monday, June 21, 2010

79. Monday, June 21, 2010

80. Degree 5
Monday, June 21, 2010

81. Degree 4
Monday, June 21, 2010

82. Degree 1
Monday, June 21, 2010

83. Monday, June 21, 2010

84. Monday, June 21, 2010

85. From here
Monday, June 21, 2010

86. To here
From here
Monday, June 21, 2010

87. To here
From here
Path Length= 3
Monday, June 21, 2010

88. CLUSTERING
Monday, June 21, 2010

89. SmallWORLDS
Monday, June 21, 2010

90. Network
FUNCTIONALITY
Monday, June 21, 2010

91. Monday, June 21, 2010

92. Information
DIFFUSION
Monday, June 21, 2010

93. Information
DIFFUSION depends on Path Length
Monday, June 21, 2010

94. Monday, June 21, 2010

95. Robustness to
FAILURE depends on degree distribution
Monday, June 21, 2010

96. Networks and
COMPLEXITY
Monday, June 21, 2010

97. NODES
Monday, June 21, 2010

98. AGENTS
Monday, June 21, 2010

99. Monday, June 21, 2010

100. Schools of
FISH
Monday, June 21, 2010

101. Schools of
FISH
Flocks of
BIRDS
Monday, June 21, 2010

102. Monday, June 21, 2010

103. Standing
OVATIONS
Monday, June 21, 2010

104. Standing
OVATIONS
Audience
PARTICIPATION
Monday, June 21, 2010

105. Agents
Landscapes
Emergence
Complexity
Criticality
Connectedness
Monday, June 21, 2010

106. Emergence
Monday, June 21, 2010

107. Slime
Monday, June 21, 2010
MOLD

108. Slime Mold Emergence
Monday, June 21, 2010

109. Monday, June 21, 2010

110. Conway’s
Game
of
Monday, June 21, 2010
LIFE

111. Gameof
Conway’s
LIFE
1. Any live cell with fewer than two live neighbours
dies.
2. Any live cell with more than three live neighbours
dies.
3. Any live cell with two or three live neighbors lives.
4. Any dead cell with exactly three live neighbors
comes to life.
Monday, June 21, 2010

112. Monday, June 21, 2010

113. Monday, June 21, 2010

114. Monday, June 21, 2010

115. Surprise!
it’s a
COMPUTER
Monday, June 21, 2010

116. Von Neumann
ARCHITECTURE
Monday, June 21, 2010

117. Monday, June 21, 2010

118. Monday, June 21, 2010

119. Monday, June 21, 2010

120. Ant
COLONIES
Monday, June 21, 2010

121. Monday, June 21, 2010

122. Proceed with
CAUTION
Monday, June 21, 2010

123. Weak
EMERGENCE
Monday, June 21, 2010

124. Weak
EMERGENCE
Monday, June 21, 2010

125. Weak
EMERGENCE
Can’t predict it
Monday, June 21, 2010

126. Weak
EMERGENCE
Can’t predict it
CAN explain it after the fact
Monday, June 21, 2010

127. Strong
EMERGENCE
Monday, June 21, 2010

128. Strong
EMERGENCE
Monday, June 21, 2010

129. Strong
EMERGENCE
Can’t predict it
Monday, June 21, 2010

130. Strong
EMERGENCE
Can’t predict it
Can’t explain it after the fact either!
Monday, June 21, 2010

131. Strong
EMERGENCE
Can’t predict it
Can’t explain it after the fact either!
It’s just there, man
Monday, June 21, 2010

132. Strong
EMERGENCE
Can’t predict it
Can’t explain it after the fact either!
It’s just there, man
Deal with it
Monday, June 21, 2010

133. I said...
CAUTION
Monday, June 21, 2010

134. Software as a
COMPLEX
Profession
Monday, June 21, 2010

135. Lean says:
Monday, June 21, 2010

136. Lean says:
Optimize
the
WHOLE
Monday, June 21, 2010

137. Lean says:
Optimize
the
WHOLE
http://agilesoftwaredevelopment.com/blog/pbielicki/optimize-the-whole
Monday, June 21, 2010

138. Optimize
THIS!
Monday, June 21, 2010

139. “This is the constitutional limitation of
man's knowledge and interests, the fact
that he cannot know more than a tiny
part of the whole of society and that
therefore all that can enter into his
motives are the immediate effects which
his actions will have in the sphere he
knows.”
—F.A. Hayek
Monday, June 21, 2010

140. AGENT-
BASED
DECISION
MAKING
Monday, June 21, 2010

141. Monday, June 21, 2010

142. Software
Architecture
Monday, June 21, 2010

143. What kind of
Software
Architecture would look like an
ANT
Monday, June 21, 2010
COLONY?

144. Monday, June 21, 2010

145. Monday, June 21, 2010

146. Monday, June 21, 2010

147. SOAP
the way
Works
Monday, June 21, 2010

148. SOAP
the way
Works
Desktop App
Web Service
Monday, June 21, 2010

149. SOAP
the way
Works
Desktop App
<soap:Envelope>
make me a sandwich
</soap:Envelope>
Web Service
Monday, June 21, 2010

150. SOAP
the way
Works
Desktop App
Web Service
Monday, June 21, 2010

151. the way
<soap:Envelope>
SOAP
Works
FAIL
DELI009283
</soap:Envelope>
Desktop App
Web Service
Monday, June 21, 2010

152. SOAP
the way
Works
Desktop App
Web Service
Monday, June 21, 2010

153. SOAP
the way
Works
Desktop App
<soap:Envelope>
make me a pastrami
on rye?
</soap:Envelope>
Web Service
Monday, June 21, 2010

154. SOAP
the way
Works
Desktop App
Web Service
Monday, June 21, 2010

155. the way
<soap:Envelope>
SOAP
Works
FAIL
DELI276193
</soap:Envelope>
Desktop App
Web Service
Monday, June 21, 2010

156. Monday, June 21, 2010

157. Contracts are
Imposed
from the
TOP
Monday, June 21, 2010
DOWN

158. Monday, June 21, 2010

159. Hypertext as the
Engine
of
APPLICATION
STATE
http://bit.ly/HATEOAS
Monday, June 21, 2010

160. HATEOAS
the way
Works
Monday, June 21, 2010

161. HATEOAS
the way
Works
Service
Web Service
Monday, June 21, 2010

162. HATEOAS
the way
Works
Service
GET /sandwich
Web Service
Monday, June 21, 2010

163. HATEOAS
the way
Works
Service
Web Service
Monday, June 21, 2010

164. the way
HATEOAS
Works
500 ERROR
<link rel=”bread” />
<link rel=”ingredient” />
Service
Web Service
Monday, June 21, 2010

165. HATEOAS
the way
Works
Service
Web Service
Monday, June 21, 2010

166. HATEOAS
the way
Works
Service
POST /sandwich
bread=rye
meat=pastrami
Web Service
Monday, June 21, 2010

167. HATEOAS
the way
Works
Service
Web Service
Monday, June 21, 2010

168. the way
HATEOAS
Works
200 OK
<link href=”eat” />
<link href=”side” />
Service <sandwich-body>...
Web Service
Monday, June 21, 2010

169. Make me a
Add Toppings
Sandwich
Checkout
Toast Bun
Monday, June 21, 2010

170. Make me a
Add Toppings
Sandwich I make
sandwiches.
Checkout
Toast Bun
Monday, June 21, 2010

171. Make me a
Add Toppings
Sandwich Give me a
sandwich, and I
can decorate it
with toppings.
Checkout
Toast Bun
Monday, June 21, 2010

172. Make me a
Add Toppings
Sandwich
I toast
sandwich
buns.
Checkout
Toast Bun
Monday, June 21, 2010

173. Make me a
Add Toppings
Sandwich
I exchange
sandwiches
for Federal
Reserve
Notes.
Checkout
Toast Bun
Monday, June 21, 2010

174. Make me a
Add Toppings
Sandwich
Checkout
Toast Bun
Monday, June 21, 2010

175. Monday, June 21, 2010

176. Behavior
Emerges
from the
EDGES
Monday, June 21, 2010
IN

177. Monday, June 21, 2010

178. Class
Are your
Dependencies
like a
RICE PILE?
Monday, June 21, 2010

179. Monday, June 21, 2010

180. Afferent
COUPLING
A class's afferent coupling is a measure of how many
other classes are coupled to it through method calls,
field accesses, inheritance, arguments, return
types, and exceptions.
Monday, June 21, 2010

181. remember the Power Law
DISTRIBUTION
Monday, June 21, 2010

182. grails-web
900
675
450
225
0
Monday, June 21, 2010

183. Hibernate 3
1500
1125
750
375
0
Monday, June 21, 2010

184. Spring 3 Core
300
225
150
75
0
Monday, June 21, 2010

185. having a
Monday, June 21, 2010

186. having a
Scale-Free
CODE BASE
Monday, June 21, 2010

187. Monday, June 21, 2010

188. toward a
COMPLEX
THEORY of
SOFTWARE
DEVELOPMENT
Monday, June 21, 2010

189. Agents
Landscapes
Emergence
Complexity
Criticality
Connectedness
Monday, June 21, 2010

190. Thank You
Tim Berglund
www.augusttechgroup.com
tim.berglund@augusttechgroup.com
@tlberglund
Monday, June 21, 2010

191. Photo Credits
Slime Mold Cells
http://campus.queens.edu/faculty/jannr/Botany/images/slimies/slimeMolds/slimeMold1152.jpg
Car Top View
http://www.motiontrends.com/2006/m09/Volvo/C30.shtml
Ants
http://www.flickr.com/photos/binux/2495709841
Traffic Jam
http://www.flickr.com/photos/lynac/321100379/
Turning Machine
http://www.ecs.syr.edu/faculty/fawcett/handouts/webpages/CoreTechnologies.htm
VonNeumann Machine
http://en.wikipedia.org/wiki/File:Von_Neumann_architecture.svg
Ant Colony
http://www.bioone.org/doi/full/10.1672/1536-2442%282004%29004%5B0001%3ATNAOTF%5D2.0.CO%3B2
Mt. Fuji
http://www.flickr.com/photos/mtsn/229410448
Snowy Mountains
http://www.flickr.com/photos/huzhead/85362599
Portrait of Frederick Winslow Taylor
http://upload.wikimedia.org/wikipedia/commons/9/90/Frederick_Winslow_Taylor_crop.jpg
Female Velvet Ant (in Work Load Illustration)
http://www.flickr.com/photos/markop/1036891509
Frederick Hayek
http://www.lancs.ac.uk/staff/ecagrs/Hayek%20quotes.htm
Monday, June 21, 2010