Modeling Dynamic Systems

1 Introduction.- 1 Modeling Dynamic Systems.- 1.1 Model Components.- 1.2 Dynamic Modeling as a Skill and Art.- 1.3 Modeling in STELLA.- 1.4 Principles of Modeling.- 2 Some General Methods for Modeling.- 2 Four-Model Set.- 2.1 Stimulus-Response Model.- 2.2 Self-Referencing Model.- 2.3 Goal-Seeking Model.- 2.4 Goal-Setting Model.- 2.5 Examples.- 2.5.1 Exponential Decay of a Stock.- 2.5.2 Newtonian Cooling.- 3 Gradual Development of a Dynamic Model.- 3.1 Modeling Industrialization for a Simple Agrarian Society.- 3.2 Impacts of Per Capita Food Consumption on Population Growth.- 3.3 Adding Agriculture.- 3.4 Adding Industry.- 4 Two Independent Variables.- 4.1 Population Cohorts.- 4.1.1 Basic Cohort Model.- 4.1.2 Population Cohort Array.- 4.1.3 U.S. Population Growth.- 4.2 River Toxins.- 5 Randomness.- 5.1 Flipping a Coin.- 5.2 Intoxication Model.- 6 Positive and Negative Feedback.- 6.1 The Basic Model.- 6.2 Positive Feedback with Fixed Points.- 6.3 Elaborations.- 7 Derivatives and Lags.- 7.1 Introduction.- 7.2 Applications of Derivatives and Lags.- 7.2.1 Simple Population Model.- 7.2.2 Two-Population Model.- 3 Chemistry Models.- 8 The Law of Mass Action.- 8.1 Breakdown of Nitrogen Dioxide into Nitrogen Oxide and Oxygen.- 8.2 Stratospheric Ozone Depletion.- 9 Chance-Cleland Model for Enzyme-Substrate Interaction.- 10 The Olsen Oscillator.- 4 Genetics Models.- 11 Mating of Alleles.- 11.1 Heterozygosity and Disease Resistance.- 11.2 The Mating of Two Alleles into a Genotype: Proving the Hardy-Weinberg Law.- 12 Natural Selection and Mutation.- 13 Artificial Worms.- 5 Ecological Models.- 14 Robin Population.- 15 Two-Stage Insect Model.- 16 The Zebra Mussel.- 17 Single Cell Forest.- 18 Predator-Prey Models.- 18.1 Basic Model of Predator-Prey Interactions.- 18.2 Spatial Predator-Prey Model.- 19 Epidemic Modeling.- 20 Reestablishment of Wolves.- 21 Lyme Disease.- 22 Tragedy of the Commons.- 6 Economic Models.- 23 Introduction to Modeling Economic Processes.- 24 The Competitive Firm.- 25 The Monopolistic Firm.- 25.1 Basic Model.- 25.2 Taxing Monopolies.- 26 Competitive Equilibrium.- 27 Substitution.- 27.1 Isoquants.- 27.2 Finding the Profit-Maximizing Output Level and Input Combinations.- 28 Time Value.- 29 Opportunity Cost.- 30 Optimal Tree Cutting.- 31 Fisheries Reserve Model.- 32 Dynamic Scarcity.- 32.1 Competitive Scarcity.- 32.2 Monopoly Scarcity.- 33 Market Game.- 34 Pig Cycle.- 7 Engineering Models.- 35 The Assembly Line.- 35.1 Basic Model.- 35.2 Car Assembly Line.- 36 Models of Gravity and Acceleration.- 36.1 Falling Rock.- 36.2 Projectile Motion.- 36.3 Mass-Damper-Spring.- 36.4 Mechanical Amplifier.- 37 Chaos.- 37.1 A New Paradigm.- 37.2 Jenson Chaos.- 37.3 Lorenz Chaos.- 37.4 Two-Well Chaos.- 8 Conclusion.- 38 Beginning a Dialog.- Appendixes.- A1 System Requirements.- A1.1 Macintosh.- A1.2 Windows.- A2 Quick Help Guide.- A2.1 Overview of the STELLA(r) Operating Environment.- A2.2 Drawing an Inflow to a Stock.- A2.3 Drawing an Outflow from a Stock.- A2.4 Replacing a Cloud with a Stock.- A2.5 Bending Flow Pipes.- A2.6 Repositioning Flow Pipes.- A2.7 Reversing Direction of a Flow.- A2.8 Flow Define Dialog-Builtins.- A2.9 Moving Variable Names.- A2.10 Drawing Connectors.- A2.11 Defining Graphs and Tables.- A2.12 Dynamite Operations on Graphs and Tables.- References.