Population Dynamics Model - ODD

I. Overview
Guiding questions
Model description
I.i Purpose
I.i.a What is the purpose of the study?
Creation of synthetic population of Celtic society living at oppidum Staré Hradisko from 150 – 30 BC.
I.ii.b For whom is the model designed?
The model is designed for scientists, particularly those interested in archaeology and demography.
I.ii Entities, state variables and scales
I.ii.a What kind of entities are in the model?
Agents: individual inhabitants
I.ii.b By what attributes (i.e. state variables and parameters) are these entities characterized?
Inhabitants are characterized by:
Age (years)
Age category  (suckling 0-1, toddler 2-3, child 4-9, older-child 10-14, young-adult 15-19, adult 20-49, elder over 49 years)
Gender  (male, female)
I.ii.c What are the exogenous factors/drivers of the models?
Exogenous factor: immigration (constant number of inhabitants per year)
I.ii.d If applicable, how is space included in the model?
Space is not included
I.ii.e What are the temporal and spatial resolutions and extents of the model?
1 time step = 1 year.
The simulation runs for 120 years.
I.iii Process overview and scheduling
I.iii.a What entity does what, and in what order?
1.      Every step (year) each inhabitant gets older (or dies).
2.      Female between 15 and 50 can give birth.
3.      If immigration <> 0, appropriate number of new inhabitants is added.
4.      If population decline is requested, appropriate number of inhabitants is removed.
II. Design Concepts
II.i Theoretical and Empirical Background
II.i.a Which general concepts, theories or hypotheses are underlying the model’s design at the system level or at the level(s) of the submodels (apart from the decision model)? What is the link to complexity and the purpose of the model?
Underlying concepts and theories:
Archeological evidence for Staré Hradisko and other oppida [RESOURCE]
Malthus’ theory of population growth

II.i.b On what assumptions is/are the agents’descision model(s) based?
Ad-hoc rule: two birth-rate-functions using random numbers were defined experimentally; avg. number of newborns per female =
Real-world observations: life tables applied in get-older procedure
Rule of thumb: the same age structure at time 0 and 120 is checked.
II.i.c Why is a/are certain decision model(s) chosen?
General theoretical considerations about fertility of a woman between 15-50 were applied in the birth-rate-functions, because there are no exact data about Celtic population.
II.i.d If the model / a submodel (e.g. the decision model) is based on empirical data, where does the data come from?
Archeological evidence for Staré Hradisko and other oppida – theoretical assumption about the initial population: 600-800 inhabitants
Approximated Life tables [Saller]
Food calorie table is used for computation of total consumption of the population (Appendix 1)
II.i.e At which level of aggregation were the data available?
Life tables for 5-years intervals were approximated.
II.ii Individual Decision Making

Individual decision making is not included.
II.iii Learning

Learning in not included.
II.iv Individual Sensing

Individual sensing is not included.
II.v Individual Prediction

Individual prediction is not included.

II.vi Interaction

No interactions

II.vii Collectives

No collectives.
II.viii Heterogeneity
II.viii.a Are the agents heterogeneous? If yes, which state variables and/or processes differ between the agents?
Birth-rate function is used only for female inhabitants between 15-50.
Consumption differs for different age groups (Appendix 1)
II.viii.b Are the agents heterogeneous in their decision-making? If yes, which decision models or decision objects differ between the agents?
II.ix Stochasticity
II.ix.a What process (including initialization) are modeled by assuming they are random or partly random?
Initial age structure of the population
Birth-rate function
Get-older function

II.x Observation
II.x.a What data are collected from the ABM for testing, understanding, and analyzing it, and how and when are they collected?
At the end of every time step (year), the age structure of the population and the consumption of the population are stored in data files.

II.x.b What key results, outputs or characteristics of the model are emerging from the individuals? (Emergence)
Population growth or decline emerges depending on birth-rate-function (linear or normal), approximated life tables (3 or 5) and decline scenario.
III. Details
III.i Implementation Details
III.i.a How has the model been implemented?
III.i.b Is the models accessible and if so where?
Can be made available upon request
III.ii Initialization
III.ii.a What is the initial state of the model world, i.e. at time t=0 of a simulation run?
Values from interface sliders for:
Initial number of inhabitants
Birth probability parameter
Number of immigrants per year
Choices of interface choosers:
Type of birth-rate function
Type of life tables
Type of initial age structure of population
III.ii.b Is the initialization always the same, or is it allowed to vary among simulations?
Initial values are varied
III.ii.c Are the initial values chosen arbitrarily or based on data?
Initial number of inhabitants should be between 600-800 (theoretical assumption about the population in the settlement Staré Hradisko)

III.iii. Input Data
III.iii.a Does the model use input from external sources such as data files or other models to represent processes that change over time?
Life tables from a data file
III.iv. Submodels
III.iv.a What, in detail, are the submodels that represent the process listed in “Process overview and scheduling”?
Population scenarios:
1.      Normal growth (baseline)
2.      Sudden decline caused by emigration
3.      Slow continuous decline caused by emigration
4.      Sudden decline caused by epidemy
III.iv.b What are the model parameters, their dimension and reference values?
Initial population 400-1200, increment 50 (recommended value 600-800)
Life table: 3,5, interpolated 3, interpolated 5
Birth probability 0-100
Immigrants per year 0-10
Decline year 1-120 (recommended value 70-80)
Decline 0-1, increment 0.005
III.iv.c How were submodels designed or chosen, and how were they parameterized and then tested?

Appendix 1

Age category
Older child – female
Older child – man
Young adult – female
Young adult – man
Adult – female
Adult – man

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