Class HistoricalDemography

java.lang.Object

org.episteme.social.history.HistoricalDemography

public final class HistoricalDemography
extends Object

Models historical population dynamics, growth rates, and carrying capacity estimates. Provides statistical models for demographic analysis across different historical eras.

Since:

1.0

Version:

1.1

Author:

Silvere Martin-Michiellot, Gemini AI (Google DeepMind)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	HistoricalDemography.DemographicSnapshot	Data record representing population status at a point in time.

Method Summary

Modifier and Type	Method	Description
static Real	dependencyRatio(int age0to14, int age15to64, int age65plus)	Calculates the dependency ratio.
static Real	doublingTime(double growthRate)	Calculates the doubling time of a historical population.
static Real	estimateCarryingCapacity(double landAreaKm2, String technologyEra)	Estimates Carrying Capacity (K) based on land area and historical technology level.
static List<HistoricalDemography.DemographicSnapshot>	globalHistory()	Returns a predefined list of global population snapshots throughout history.
static Real	projectPopulation(long p0, double r, int years)	Projects population based on Malthusian growth model.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

projectPopulation

public static Real projectPopulation(long p0,
 double r,
 int years)

Projects population based on Malthusian growth model. Formula: P(t) = P0 * e^(rt)

Parameters:

p0 - initial population

r - annual growth rate (decimal, e.g., 0.01 for 1%)

years - number of years to project

Returns:

projected population as a Real number

doublingTime

public static Real doublingTime(double growthRate)

Calculates the doubling time of a historical population. Formula: T = ln(2) / r

Parameters:

growthRate - annual growth rate

Returns:

doubling time in years as a Real number

estimateCarryingCapacity

public static Real estimateCarryingCapacity(double landAreaKm2,
 String technologyEra)

Estimates Carrying Capacity (K) based on land area and historical technology level.

Parameters:

landAreaKm2 - land area in square kilometers

technologyEra - the historical era (e.g., "paleolithic", "neolithic", "medieval")

Returns:

estimated carrying capacity as a Real number

Throws:

NullPointerException - if technologyEra is null

dependencyRatio

public static Real dependencyRatio(int age0to14,
 int age15to64,
 int age65plus)

Calculates the dependency ratio. Formula: (young + old) / working age population.

Parameters:

age0to14 - population aged 0-14

age15to64 - population aged 15-64

age65plus - population aged 65 or older

Returns:

dependency ratio as a Real number

globalHistory

public static List<HistoricalDemography.DemographicSnapshot> globalHistory()

Returns a predefined list of global population snapshots throughout history.

Returns:

unmodifiable list of global demographic snapshots