1. Evolving a simulated system of enterprises with jESevol and Swarm
Pietro Terna
Department of Economics and Finance “G.Prato”
University of Torino - Italy
Evolving a simulated system of enterprises with jESevol and Swarm
web.econ.unito.it/terna
web.econ.unito.it/terna/jes
jESevol
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

2. _jES->jESlet and jESevol
_______________________________________
jES jESlet and jESevol
_jES->jESlet and jESevol
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

3. SwarmFest, CSCS, University of Michigan
From jES …
java Enterprise Simulator
… to jESlet (with a didactic goal) and …
jVE->jES
… to jESevol, to simulate an evolving system of enterprises
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

4. _______________________________________ Overview
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

5. SwarmFest, CSCS, University of Michigan
Overview 1/2
From jES (our java Enterprise Simulator), we have derived jESevol, or “Evolutionary java Enterprise Simulator”. jES is a large Swarm-based package[1] aimed at building simulation models both of actual enterprises and of virtual ones. jESevol simulates systems of enterprises or production units in an evolutionary context, where new ones arise continuously and some of the old are dropped out.
Our environment is a social space with metaphorical distances representing trustiness and cooperation among production units (the social capital). The production is represented by a sequence of orders; each order contains a recipe, i.e. the description of the sequence of activities to be done by several units to complete a specific production.
[1] Download last versions of jES, jESlet and jESevol from
overview 1
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

6. SwarmFest, CSCS, University of Michigan
Overview 2/2
Two units can cooperate in the production process only if they are mutually visible in our social network. Units that do not receive a sufficient quantity of orders, as well as the ones that cannot send the accomplished orders to successive units, disappear.
New enterprises arise, in the attempt of filling the structural holes (Burt, 1992; Walker et al., 1997) of our social network.
A complex structure emerges from our environment, with a difficult and instable equilibrium whenever the social capital is not sufficient.
References
Burt R.S. (1992), Structural Holes – The Social Structure of Competition. Cambridge, MA, Harvard University Press.
Walker G., Kogut B., Shan W. (1997), Social Capital, Structural Holes and the Formation of an Industry Network, in Organization Science. Vol. 8, No. 2, pp
overview 2
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

7. SwarmFest, CSCS, University of Michigan
We look at an incomplete production system continuously adapting itself to the reality coming from the global demand of the market …
evolving system
… while new firms arise and old ones are dropped out
To produce goods, supply chains are created and modified, according to the changes in exiting firms
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

8. _______________________________________ jES basics
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

9. SwarmFest, CSCS, University of Michigan
Three formalisms
WD side or formalism: What to Do
DW side or formalism: which is Doing What
WDW formalism: When Doing What
WD, DW, WDW
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

10. SwarmFest, CSCS, University of Michigan
A dictionary
unit = a productive structure; a unit is able to perform one of the steps required to accomplish an order
order = the object representing a good to be produced; an order contains technical information (the recipe describing the production steps)
recipe = a sequence of steps to be executed to produce a good
dictionary
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

11. _______________________________________ A flexible scheme in jESevol
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

12. SwarmFest, CSCS, University of MichiganDW
Units … 2 1 3 1
… on a toroidal space 4 2
DW: a flexible scheme 1
Each unit is able to do a specific step … 5
(left and right borders and top and bottom ones are close together) 3
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

13. SwarmFest, CSCS, University of MichiganWD
… of a recipe
with the recipes of the orders (what to do) expressed as sequences of numbers; orders with recipes are randomly generated with different lengths and structures
5 3 …
WD: recipes
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

14. DW and WD
moving around among units 2 1 3 1 4 2
moving recipes
how to choose ? 1 5 3
lack of visibility
Visibility is a metaphorical representation of trustiness and cooperation in a social network; when global visibility increases, we have more “social capital”
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

15. SwarmFest, CSCS, University of Michigan
Visibility increases with the time (initial visibility is randomly chosen)
new units appear randomly (enterprise creation)
with strategic relationships …
… or alone
visibility changes
visibility and …
some units are dropped out
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

16. SwarmFest, CSCS, University of Michigan
The left (blue) bar of each unit reports the number of waiting orders (do be done)
The right (red) bar of each unit reports the number of unsent products, due to the fact that a unit able to do the required step does not exist or is not visible
… bars
The down (grey) bar of each unit reports the number of consecutive clock ticks in which the unit has been idle
If > maxInactivity the unit is dropped out and all unsent products are lost
If > maxUnsentProducts the unit is dropped out and all unsent and waiting products are lost
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

17. _______________________________________
An introductory case, robust and fragile
_an introductory case
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

18. the parameters, robust introductory case
Introductory robust case
potentialUnitTypes 5
unitGenerationInitialP 1
potentialUnitNumberPerType 2
newUnitGenerationP 0.0
interVisibilityMinLevel 0
increasingVisibilityStep 0.0
maxInactivity 10
maxUnsentProducts 10
max n. of types and max presence per type, here 5 * 2 with p=1
p of a new unit in each cycle, with a random type
in this basic case all units are visible and visibility does not change
the parameters, robust introductory case
we assume that an actual firm is dropped out from the market after three months of inactivity, so 10 ticks = 3 months of history
Why 10? Our recipes have here maxStepNumber =5 and maxStepLength=2; potentially, in 10 ticks, each unit can receive an order, but only as a limit case; with this parameters the system can be exposed to a complete crash
similarly …
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

19. introductory case: robust case
Introductory robust case
only 5 units kept alive
introductory case: robust case
1,000 ticks = 25 years of actual time
PRODUCTION
global/potential
final/potential
final/global
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

20. the parameters, fragile introductory case
Introductory fragile case
potentialUnitTypes
unitGenerationInitialP 1
potentialUnitNumberPerType 1
newUnitGenerationP 0.0
interVisibilityMinLevel 0
increasingVisibilityStep 0.0
maxInactivity 10
maxUnsentProducts 10
max n. of types and max presence per type, here 10 * 1 with p=1
the parameters, fragile introductory case
Our recipes have here
maxStepNumber 10 and
maxStepLength 1
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

21. introductory case: fragile case
Basic fragile case
no units kept alive
introductory case: fragile case
150 ticks < 4 years of actual time
PRODUCTION
global/potential
final/potential
final/global
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

22. __________________________________________________
A study case, with 3 versions:
(i) basic,
(ii) increasing social capital,
(iii) with greater financial intervention of the banking system
_a study case
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

23. the parameters, basic study case
(i) basic study case, starter file 5 in jESevol
potentialUnitTypes 5
unitGenerationInitialP 0.8
potentialUnitNumberPerType 2
newUnitGenerationP 0.8
interVisibilityMinLevel 1
increasingVisibilityStep 5
maxInactivity 10
maxUnsentProducts 10
max n. of types and max presence per type, here 5 * 2 with p=0.8
p of a new unit in each cycle, with a random type
in this study case, min visibility is 1, i.e. at least one common patch; visibility increases of 5 patches in each tick
the parameters, basic study case
Our recipes have here
maxStepNumber 5 and
maxStepLength 2
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

24. SwarmFest, CSCS, University of Michigan
(i) basic study case, starter file 5 in jESevol
a relevant variability in the number of units (social costs), with the trace of a cycle
a medium performance in term of potential production
study case: basic
1,000 ticks = 25 years of actual time
PRODUCTION
global/potential
final/potential
final/global
some form of structure seems to emerge
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

25. the parameters, increasing social capital study case
(ii) Increasing social capital study case, starter file 5.2 in jESevol
potentialUnitTypes 5
unitGenerationInitialP 0.8
potentialUnitNumberPerType 2
newUnitGenerationP 0.8
interVisibilityMinLevel 1
increasingVisibilityStep 10
maxInactivity 10
maxUnsentProducts 10
max n. of types and max presence per type, here 5 * 2 with p=0.8
p of a new unit in each cycle, with a random type
in this study case, min visibility is 1, i.e. at least one common patch; visibility increases of 10 patches in each tick
the parameters, increasing social capital study case
Our recipes have here
maxStepNumber 5 and
maxStepLength 2
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

26. study case: increasing social capital
(ii) Increasing social capital study case, starter file 5.2 in jESevol
a relevant variability in the number of units (social costs), but now with an evident cycle
a good (and increasing) performance in term of potential production
study case: increasing social capital
1,000 ticks = 25 years of actual time
PRODUCTION
global/potential
final/potential
final/global
evident structures emerge
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

27. the parameters, bank system study case
(iii) Greater financial intervention of the banking system study case, starter file 5.3 in jESevol
potentialUnitTypes 5
unitGenerationInitialP 0.8
potentialUnitNumberPerType 2
newUnitGenerationP 0.8
interVisibilityMinLevel 1
increasingVisibilityStep 5
maxInactivity 15
maxUnsentProducts 10
in this study case, min visibility is 1, i.e. at least one common patch; visibility is increases of 5 patches in each tick
the parameters, bank system study case
we assume that an actual firm is dropped out from the market after 15 ticks of inactivity, instead of 10
Our recipes have here
maxStepNumber 5 and
maxStepLength 2
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

28. study case: bank system study case
(iii) Greater financial intervention of the banking system study case, starter file 5.3 in jESevol
a less relevant variability in the number of units (reduced social costs), always with an evident cycle
a good performance in term of potential production
study case: bank system study case
1,000 ticks = 25 years of actual time
PRODUCTION
global/potential
final/potential
final/global
evident structures emerge
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

29. Stability; perspectives
Cases i, ii and iii are stable also running them for 4,000 ticks (one century)!
Short term enhancements
A lot of investigation is necessary on cases (i), (ii) and (iii) modelling explicitly the banking system, with the concurrent effects of the cases of bankruptcy in firms and banks
Using a Genetic Algorithm tool to choose units to be created at each tick and where to place them; the fitness will be generated by jESevol itself, from different points of view: the whole economic system, a specific unit, a cluster of units, …
Stability; perspectives
May 9-11, 2004
SwarmFest, CSCS, University of Michigan

30. Let run case 5.2 or 5.3 at the question time!
address again
web.econ.unito.it/terna
web.econ.unito.it/terna/jes
May 9-11, 2004
SwarmFest, CSCS, University of Michigan