Transcript Wilddog slides

Agent-Based Modeling
and Simulation
(ABMS)
Bertan Badur
[email protected]
Department of
Management Information Systems
Boğaziçi University
Collectives
• Chapter 16 of Agent-Based and Individual-Based
Modeling: A Practical Introduction, by S. F.
Railsback and V. Grimm
• NetLogo User Menual
Outline
•
.
16.4 A Wild Dog Modfel with Packs
Entities, States, Scales
• Agents:
– dogs, dog packs, disperser groups
• State variables:
• dogs
– age, sex, pack or disperser group, social status
– social atatus:
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•
•
•
•
“pup”: age less then one
“yearling”: age between 1 and 2
“subordinate”: age greater then 2 but dog is not an alpha
“alpha”: dominant sex in a pack
“disperser”: belong to a disperser not a pack
• dog packs
– list or agent set of dogs
• disperser groups:
– sex, agnet set of members
NetLogo Code
globals [n-telemar]
turtles-own [bank-bal]
to setup
ca
]
reset-ticks
end
to go
tick
if ticks > yers-to-sim [stop]
end
NetLogo Code
breed [dogs dog]
breed [packs pack]
breed [disperser-groups disperser-group]
dogs-own [
age sex status my-pack my-dispersergroup ]
packs-own [
pack-members ]
disperser-groups-own [
sex group-members ]
Initialization
• 10 packs, no disperser groups
• number of dogs in each initial pack
– Poisson – mean 5
•
•
•
•
sex: uniformly
age: uniform intergers 0 – 6
social status: according to age
alpha: for each sex, randomly among subordinates
NetLogo code (1)
create-packs initial-num-packs
[
setxy random-xcor random-ycor
set shape "box"
let num-dogs random-poisson initial-mean-pack-size
hatch-dogs num-dogs
[
set headıng random 360
fd 1
ifelse random-float 1.0 < 0.5
[set sex "male" ]
[set sex "female"]
set age random 7
set my-pack myself
set-my-status
] ; end hatch-dogs
NetLogo code (2)
set pack-members dogs with [mypack = myself]
update-pack-alphas
] ; end of create-packs
set-my-status
to set-my-status ; dog procedure
if age = 0 [set status "pup"]
if age = 1 or age = 2 [set status
"yearling"]
if age > 2 [set status
"subordinate"]
end
update-pack-alphas
to update-pack-alphas
let can-alpha-males pack-members with [sex =
"male" and status = "subordinate"]
if any? can-alpha-males [
ask one-of can-alpha-males [set status
"alpha"] ]
let can-alpha-females pack-members with [sex =
"female" and status = "subordinate"]
if any? can-alpha-females [
ask one-of can-alpha-females [set status
"alpha"] ]
end
setup
set years-to-sim 100
set carry-cap 60
set initial-num-packs 10
set initial-mean-pack-size 5
Process Overview and Scheduling (1)
• 1- age and social status updates
–
–
–
–
age is incremented
social status is updated
each pack updates its alpha
if not having an alpha a subordinate is selected
• 2- Reproduction
–
–
–
–
–
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alpha male and female or no reproduction
N: total number of dogs – not newly born
carrying capacity: 60
P: probablity of reproduction
P = 0.5 when N is 0.5 of carrying capacity
P = 0.1 whn N is carrying capacity
• 3-Dispersal
– if nosubordinate – no disperser groups
– if one subordinate withprob 0.5 for a disperser group of one
member
– if more then one subordinates of thesame sex – always form
a disperser group
– dogs no longer belong to pach
• 4- Dog mortality probabilities:
– 0.44: disperser 0.25: yearlings, 0.2: subordinates and alphas,
0.12: pups
• 5- Mortality of collectives:
– no member then collective dies
– for packs only pups die ansd packs removes
• 6- Form pack
– disperser groups with opposit sex and from different packs
– how namy times a group meets another
• poisson number of other groups
– if meets 64/% forms a pack
• set status to disperser
• update alpha
• remove disperser groups
• 7-outputs
– plots of number of dogs, disperser groups and packs
NetLogo Code - go
to go
tick
if ticks > years-to-sim [stop]
ask dogs
[
set age age + 1
set-my-status
]
ask packs [update-pack-alphas]
ask packs [reproduce]
NetLogo Code - submodels
ask packs [ disperse ]
ask dogs [ do-mortality ]
ask dogs [ do-mortality ]
ask packs [ do-pack-mortality ]
ask disperser-groups [ if count groupmembers = 0 [die] ]
ask disperser-groups [ do-packformation ]
update-output
end
reproduce
to reproduce
if ( any? pack-members with [status =
"alpha" and sex = "male"] ) and
( any? pack-members with [status =
"alpha" and sex = "female"] )
[
let n-dogs count dogs
let p logistic-func n-dogs
if random-float 1.0 < p [
let num-new-pups random-poisson 7.9
reproduce
hatch-dogs num-new-pups [
set headıng random 360
fd 1
ifelse random-float 1.0 < 0.55
[set sex "male"]
[set sex "female"]
set age 0
set status "pup"
set my-pack myself
set pack-members (turtle-set pack-members self)
] ; end of hatch
;set pack-members dogs with [my-pack = myself]
] ; reproduce
] ; any alpha
end
logistic-func
to-report logistic-func [num]
let z a + b * num
report ( exp z ) / ( 1 + exp z)
end
add to setup
set d ln (0.1 / 0.9)
set x2 carry-cap / 2
set x1 carry-cap
set b d / ( x1 - x2 )
set a d - ( b * x1 )
do-mortality
to do-mortality
if random-float 1.0 < pup-mortality-rate and
status = "pup" [die]
if random-float 1.0 < yearling-mortality-rate
and status = "yearling" [die]
if random-float 1.0 < subordinate-mortalityrate and status = "subordinate" [die]
if random-float 1.0 < alpha-mortality-rate and
status = "alpha" [die]
if random-float 1.0 < disperser-mortality-rate
and status = "disperser" [die]
end
add to setup
set pup-mortality-rate 0.12
set yearling-mortality-rate 0.25
set alpha-mortality-rate 0.20
set subordinate-mortality-rate 0.20
set disperser-mortality-rate 0.44
do-pack-mortality
to do-pack-mortality
if count pack-members = 0 [die]
if count pack-members = count pack-members With
[status = "pup"] [
ask pack-members [die]
die
]
end
disperse (1)
to disperse
let my-subordinates pack-members with [status = "subordinates"]
if not any? my-subordinates [stop]
if count my-subordinates with [sex = "female"] = 1 [
if random-float 1.0 < 0.5 [
create-disperser-group-from my-subordinates with [sex = "female"]
]
]
if count my-subordinates with [sex = "female"] > 1 [
create-disperser-group-from my-subordinates with [sex = "female"]
]
if count my-subordinates with [sex = "male"] = 1 [
if random-float 1.0 < 0.5 [
create-disperser-group-from my-subordinates with [sex = "male"]
]
]
disperse (2)
if count my-subordinates with [sex =
"male"] = 1 [
if random-float 1.0 < 0.5 [
create-disperser-group-from mysubordinates with [sex = "male"]
]
]
if count my-subordinates with [sex =
"male"] > 1 [
create-disperser-group-from mysubordinates with [sex = "male"]
]
end ; to disperse
create-disperse-group-from (1)
to create-disperser-group-from [some-dogs]
hatch-disperser-groups 1 [
set group-members some-dogs
set sex [sex] of one-of some-dogs
set shape "car"
set headıng random 360
fd 2
create-disperse-group-from (2)
ask some-dogs [
set my-disperser-group myself
set status "disperser"
set color green
move-to my-disperser-group
set headıng [headıng] of my-disperser-group
fd 1 + random-float 2
] ; end of ask some-dogs
create-disperse-group-from (3)
let dogs-former-pack [my-pack] of
one-of some-dogs
ask dogs-former-pack [
set pack-members pack-members
with [status != "disperser"]
]
end
to do-pack-formation
let num-groups-met random-poisson count ( dispersergroups ) - 1
repeat num-groups-met [
let can-group-merge one-of other disperser-groups
if any? can-group-merge [
if [sex] of can-group-merge != [sex] of myself
and
( [my-pack] of one-of [group-members] of cangroup-merge =
[my-pack] of one-of [group-members] of
myself ) and
random-float 1.0 < 0.64
[merge-disperser-groups myself can-groupmerge]
]
]
end
merge-disperser-groups
to merge-disperser-groups [disperser-group1
disperser-group2]
hatch-packs 1 [
set pack-members [group-members] of
disperser-group1
set pack-members (turtle-set pack-members
[group-members] of disperser-group2 )
ask pack-members [
set status "subordinate"
set my-pack myself
update-pack-alphas
]
]
ask disperser-group1 [die]
ask disperser-group2 [die]
end