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1
Equilibrium analysis ofthe distribution of information in human society
revisited in August, 2009
Shigeki Goto (Waseda University)
Hisao Nojima (Seijo University)
2
Friends are my treasures.
In Network Society, each individual lives
autonomously. Still, you are not alone.
Network maniac lonely life
is not a correct diagram.
The ICT Revolution is the second phase of the
Industrial Revolution.*) Information and Communication Tech.
3
Adam Smith and the Industrial Revolution
His famous book:“An inquiry into the nature andcauses of the wealth of nations”
The Industrial Revolution and transportation technology
Information and communication
4
Concept of division of labor
Mr. A has10 books
Ms. B has10 books
Lend and
Borrow
5
Mr. Aknowledge10
knowledge 10
1Total knowledge 60
cost10
cost 1
Mr. A
Total cost 15
Division of labor and others
1 1 1 110 10 10 10 10
6
Mr. Aknowledge 10
Knowledge 10
60Total knowledge
cost 10
10cost 10
Mr. A
60Total cost
When each individual lives alone
10 10 101010 10 10 10
7
brain
large society
brain
end users
Theory of overflow
8
2-layer
3-layer
Network society is not flat.
brain
gate keepers
9
Network society is not flat.
10
Distribution of information
You do not have to be an expert in all the areas.
There is a social structure for division of labor.Investigation on the human memory (Wenger, 1987)
baseball cooking
A: baseball fan Good --
B: cooking expert -- Good
A & B Good Good
11
When others would help you.
A case study T. Sakatani and H. Nojima,
The structure of information flow among network users, in Advances in Japanese Cognitive Science, Vol. 5, pp.49—71, 1992.
FindingsThere is a three-layer structure.The roles of gatekeepers (or brokers) are
important.
12
Distribution of information Research scientists at NTT Laboratories
About 180 people Inquiry
145 scientist responded. The number of network users is 95.
Investigation Question-Asking behavior
ÅEÅEÅE
É\ÉtÉgÉEÉFÉAå§ãÜèä äÓëbå§ãÜèä
É\ÉtÉgÉEÉFÉAäJî°ïî
É\ÉtÉgÉEÉFÉAãZèpïî
èÓïÒâ»äwå§ãÜïî
ï®éøâ»äwå§ãÜïî
ç¼óøï®ê´å§ãÜïî
4### 1### 2### 3###
11##
1301 1302 1303 1304
12## 13##
å§ãÜïî
ÉOÉãÅ[Év
å¬êl
íŠçÇÃëŒè€(ïêë†ñÏínãÊ)
éøñ‚ǵǃǰÇÈêlÇÃêî
êlêî
êl40
35
30
25
20
15
10
5
00 1 2 3 4 5 6 7 8 9 10 11 12 13 15 19 28 31 32
How many people ask you?
13
Three-layer structure
Brains
Gate-keepers
End Users
E11...E 1n
End Users
E21...E2n
End Users
E31...E3n
B1
B2
B3B4
B5
GK1 GK2 GK3 GK4 GK5
14
Characteristics of the structure It is an informal structure. It does not follow the
structure of the company. Three groups of people
Brains: small number of people who have much knowledge Gate Keepers: small number of local experts who can
cover wide area of topics End Users: many people who have little knowledge
Each brain recognizes who are other brains. A brain has his/her specific field of knowledge. Each gatekeeper does not know who are other
gatekeepers. A gatekeeper does not have any specific area of
knowledge. He/she knows general information.
15
Equilibrium analysis of the three-layer structure
S. Goto and H. Nojima,Equilibrium analysis of the distribution of information in human society,Artificial Intelligence, 75 (1995), pp.115—130.
H. Nojima,Cognitive Analysis on Roles of Others in Problem Solving,Ph.D Thesis, Waseda University, March, 2003.
16
The three-layer structure is economically reasonable.
Brains
Gate-keepers
End Users
E11...E 1n
End Users
E21...E2n
End Users
E31...E3n
B1
B2
B3B4
B5
GK1 GK2 GK3 GK4 GK5
17
Micro-ecomonics or Price theory
Knowledge as utilityEquilibrium of demand and supplyDemand — utility functionSupply — cost function
Two-layer structurea brain and end usersdivision of labor
Three-layer structureThe two-layer structure is not stable in a large society.
18
Equilibrium point
Knowledge as utility : utility function Zipf’s Law
Cost of knowledge: cost function Approximate the cost function based on computer
memory structure
At the equilibrium point, utility=cost. The equilibrium point is meaningful to a single person. He/she memorize a word, if utility > cost.
19
Utility function — Zipf’s Law
%
1010
5
3.33
2.52
1.67 1.43 1.25 1.11 1
5
00 1 2 3 4 5 6 7 8 9 10
èáà
10r
(%)
Occurrence of English words, Zipf (1949) 1st: the (10%) 2nd: of (5%) 3rd: and (3.3%) 4th: to (2.5%)
Empirical law which is applied to Population of cities Commands in Emacs Number of accesses to
popular WWW pages Use Zipf’s law as a diminishing
marginal utility function
å¿äEå¯óp
êîó
Marginal utility function
20
Equilibrium point
Knowledge as utility : utility function Zipf’s Law
Cost of knowledge: cost function Approximate the cost function based on computer
memory structures
At the equilibrium point, utility=cost. The equilibrium point is meaningful to a single person. He/she memorize a word, if utility > cost.
21
Cost function — memoryîÔóp
åXÇ ́b
åXÇ ́b
åXÇ ́b
a1
a2
a3
íPåÍÇÃêî
å¿äEîÔóp
b
a1
ÅEÅEÅE ÅEÅEÅE ÅEÅEÅE
a2a3
íPåÍÇÃêî123
Number of words
bcost b
22
Equilibrium — a single user
b
å¿äEå¯óp
å¿äEîÔóp
utility = cost
Number of words
23
Twp-layer structure
Which is better, live alone or depend on a brain? No division of labor if people live by themselves.
Division of labor means depending on others.
Cost analysis Social cost = Brain cost + End User cost
When division of labor is meaningful?
24
Equilibrium point of end users and a brain
k > 1(費用が効用を上回る)
k < 1(他者を頼る費用が効用より下)
A
BC
O: the original equilibrium pointX: depending on a brainA—B: keep memory by oneselfB—C: use the knowledge of a brain
higher cost
lower cost function
25
Equilibrium point of a brain
re
brain
originalequilibrium point
end user
Start depending on a brain A brain has more knowledge.
Utility function of a brain
26
From two-layer to three-layer
The two-layer model does not scale. The cost increases.
The links to the end users. Overflow theory
The end users should wait for a long time, and the cost for communications would increase.
The relay point — a gatekeeper
brains
end users
・・・
・・・
・・・
・・・
27
Three-layer structure is found elsewhere
Popular structure in human society
Examples education WWW Server--client bibliography distribution
Brain teacher original WEB page
server Originalpaper
factory
Gate- Keeper
teaching assistant
cache server request manager textbook Wholesaledistributor
End User student browser client paper retailer
28
Applications
Several issues are discussed from this point. How to make good successors of brains.
The difference in the amount of knowledge is huge between a brain and an end user.
It is economically sound to depend on brains. The issue is how to make good successors of brains.
How to solve the overflow. It is not necessary to have human gatekeepers. Manuals, dictionaries, textbooks are helpful to end
users.
29
Conclusion
Three-layer structure :
Knowledge is distributed.
The structure is economically reasonable.
30
Lesson: division of labor The concept was well described by Adam Smith.
Transportation supports the industrial revolution. ICT will further promote the division of labor.
Many things are based on information.
Network society is not simply flat.Layered structures are stable in a large society.
Brain
Broker =Gate-keeper
End User