Diseases of complexity

1
Diseases of complexity
Fragile

• Parasites

Complex development
Uncertainty
Robust
2
Diseases of complexity
Fragile

• Parasites

Complex development
Immune response
Uncertainty
Robust
3
Diseases of complexity
Fragile
Autoimmune disease

• Parasites

Complex development
Immune response
Uncertainty
Robust
4
Diseases of complexity
Fragile
Autoimmune disease

• Parasites

Complex development
Immune response
Regeneration/renewal
Uncertainty
Robust
5
Diseases of complexity
Fragile
Cancer
Autoimmune disease

• Parasites

Complex development
Immune response
Regeneration/renewal
Uncertainty
Robust
6
Diseases of complexity
Fragile
Cancer
Autoimmune disease

• Parasites

Complex development
Immune response
Regeneration/renewal
Complex society
Uncertainty
Robust
7
Diseases of complexity
Fragile
Epidemics
Cancer
Autoimmune disease

• Parasites

Complex development
Immune response
Regeneration/renewal
Complex society
Uncertainty
Robust
8
Diseases of complexity
Fragile
Epidemics
Robust
Cancer
Autoimmune disease

• Parasites

Complex development
Yet fragile
Immune response
Regeneration/renewal
Complex society
Uncertainty
Robust
9
Complexity?
Fragile
Robust
But there are unavoidable tradeoffs.
Greater complexity can provide improved
robustness.
Yet fragile
Uncertainty
Robust
10
Complexity?
Fragile
Robust
There are new conservation laws for
robustness/fragility. If exploited, net benefits
are possible. If not, disasters loom.
Yet fragile
Uncertainty
Robust
11
As modern cars, planes, computers, etc have
exploding internal complexity, they are simpler
to use and more robust. They tend to work
perfectly or not at all.
12
As modern cars, planes, computers, etc have
exploding internal complexity, they are simpler
to use and more robust. They tend to work
perfectly or not at all.
13
Robustness A property of a system is
relatively unchanged by a class of
perturbations
14
Clothing
15
The clothing hourglass
Garments
Dress
Shirt
Slacks
Lingerie
Coat
Scarf
Tie
Wool
Cotton
Nylon
Silk
Polyester
Rayon
Material technologies
16
The clothing hourglass
Modules
Garments
Dress
Shirt
Slacks
Lingerie
Coat
Scarf
Tie
Wool
Cotton
Nylon
Silk
Polyester
Rayon
Material technologies
17
Protocol
Modules
18
Garments
Dress
Shirt
Slacks
Lingerie
Coat
Scarf
Tie
Sewing
Cloth
Thread
Fiber
Wool
Cotton
Nylon
Silk
Polyester
Rayon
Material technologies
19
Protocol
Modules
Robust and highly evolvable
Fragile and hard to change
20
T-Shirt
Jacket
Shirt
Tie
Boxers
Shoes
Coat
Slacks
Socks
Modules?
Silk
Wool
Nylon
Rayon
Cotton
Polyester
21
T-Shirt
Jacket
Shirt
Tie
Boxers
Shoes
Coat
Slacks
Socks
22
Horizontal decomposition
Garments
Dress
Shirt
Slacks
Lingerie
Coat
Scarf
Tie
Sewing
Vertical decomposition
The hourglass
Cloth
Wool
Cotton
Nylon
Silk
Polyester
Rayon
Horizontal decomposition
Material technologies
23
Lego
24
The LEGO connector protocol
Robust Mesoscale
25
Uncertainty
Robust Mesoscale
Robust yet fragile
Uncertainty
26

• The essence of Lego is the snap protocol.
• Evolvability of new modules and toys.
• Snap is largely hidden in completed toys.
• Snap facilitates building complex toys and is
  source of robustness and fragility.

Robust Mesoscale
27
Uncertainty
Robust Mesoscale
Robust
Uncertainty
28
Yet fragile

• Catastrophic if it fails
• Difficult to change
• Must be protected
• Optimal point of attack

Robust Mesoscale
29
Yet fragile
Protocols allow for the creation of large complex
networks, with rare but catastrophic cascading
failures.
30
Principles

• Highly evolved systems are robust yet fragile
  (conservation of fragility)
• Internal complexity driven by regulatory
  networks sensors actuators
• Complexity/robustness/fragility spirals
• Protocols
• Facilitates robustness and evolvability
• Creates new fragility and brittleness

31
The evolution of complexity
32
Suppose you want to put a structure on wheels?
Easy Find Lego parts with wheels.
33
Suppose you want to motorize a vehicle with
wheels?
Easy Add Lego motors,gears and battery.
34
Suppose you want to motorize a vehicle with
wheels?
Easy Add Lego motors,gears and battery.
Additional protocols and modules.
35
This cart/motor/gear configuration could be a
module that is reused in many toys.
36
Q Suppose you wanted to change a Lego car that
had a motor and could move across the room, to a
Lego car that could also avoid obstacles as it
moved. What would happen to the cost and
complexity? A Both cost and complexity would
go up by orders of magnitude. Until recently,
this would have been essentially impossible. Now
it is doable, all parts are available from Lego,
but it is still very challenging.
37
Sensors
Control
Vehicle
Sensors
Actuators
Control
Vehicle
Size ? Complexity
(Size of blocks reflects complexity of
components.)
38
Complexity
protocols
structure
wheels
motor
controls
39
Fragility as a conserved quantity

• This conservation (constraint) law is as
  important as the more familiar ones for matter
  and energy.
• If we understand and manage it, we can use it to
  our advantage (like matter and energy). Failure
  means disaster.
• Technology so far has relied on our mastery of
  matter/energy and information. We must now
  urgently master complexity and fragility (and
  information is only a small part of it).

40
Fragility as a conserved quantity

• Laws
• Regulations
• Bureaucracy
• Markets
• ..are all just control systems, and unfortunately
  all preserve some kinds of fragility (Lessig).
• Much of the debate about their relative merits
  are ideological and unscientific, analogous to
  arguing about whose perpetual motion machine is
  better.

41
Operating systems
42
Various functionality
Digital
Analog substrate
43
Applications
Software Hardware
Modern Computing
Operating System
Hardware
44
Applications
Interface
Application
Operating System
Operating System
Hardware
Computer
Board
Device
45
Huge variety of Applications
Interface
Application
Operating System
Huge Variety of Hardware
Computer
Board
Device
46
The rest is hidden from the user
Interface
Application
Operating System
Computer
Board
Device
47
Interface
Application
Operating System
Computer
Board
Device
48
(No Transcript)
49
VLSI design
Interface
Application
Operating System
Computer
Board
Device
50
VLSI 1975?
Interface
Software?
Application
Operating System
Computer
Board
Device
51
VLSI design
Interface
Software?
Application
Operating System
Computer
Board
Device
52
Implications?
Interface
Software?
Application
Operating System
Computer
Board
Device
53
Interface
Application
Operating System
Computer
Board
Device
54
Internet
Interface
Interface
Application
Application
Operating System
TCP
Operating System
IP
Computer
Board
Computer
Board
Device
Device
55
Internet
Interface
Application
Application
TCP
Operating System
TCP
Simplify
IP
IP
Computer
Board
Link
Device
56
Internet
Application
Application
TCP
TCP
IP
IP
Link
Link
Link
57
Internet
Application
Application
Hidden from the user
TCP
TCP
IP
IP
Link
Link
Link
58
108-109 interconnected computers, each with
Interface
Application
?108 lines of software code
Operating System
TCP
IP
Computer
Board
Device
59
Phenotype
Interface
Application
Operating System
TCP
IP
Computer
Instructions
Logic
Board
Topology
Device
Geometry
Timing
Fabrication
Silicon
?1017 transistors
60
More than 99 of computers are embedded,
performing automated control without human
intervention or interface.
Physical systems
Application
Operating System
TCP
IP
Computer
Board
Device