Featured Author

John Hayward

I am a Visiting Research Fellow in Mathematics at the University of South Wales. Before my retirement, I was a senior lecturer at the university, teaching specialist courses in system dynamics, mathematical modelling and agent-based methods. I was awarded a BSc in astrophysics, and a PhD in applied mathematics, from the University of London, and then spent my career as a lecturer in mathematics. My research is in mathematical sociology with applications to the spread of social phenomena, such as ... Read more

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#1

Lactase Enzyme Simulation with Data Analysis

sim7945901 runs
1147680
#2

Enzyme Diversity: Enzymes, Products, and Substrates

sim720533 runs
enzymes substrates products DNA trypsin
761496
#3

Predator-Prey-LevelA

Level A: Up and Down in the Wild: Predator and Prey This lesson allows students to explore the in ... Read more
Level A: Up and Down in the Wild: Predator and Prey This lesson allows students to explore the interactions of two animal populations (wolves and moose) within an ecosystem. One animal in the simulation is a predator. The other animal is its prey. Their populations rise and fall (oscillate) over time as they interact and impact one another.
sim227527 runs, 249 downloads
Download Model
ecosystem population predator prey oscillation
270648
#4

Photosynthesis Model

sim1394606 runs
145548
#5

Information Processing and Neurophysiology Model

The main dependent variable measured in the model is the membrane potential (millivolts) of two diff ... Read more
The main dependent variable measured in the model is the membrane potential (millivolts) of two different neurons in a series. You will be able to add excitatory and inhibitory neurotransmitters, and compare how these modulate electrical impulses of the two neurons. Additionally, you will be able to compare the effects of three neurotoxins: Tetrodotoxin, botulinum toxin, and sarin nerve gas. While extremely lethal, these toxins are very instructive in understanding neurons because of the specific way the toxins act. Each toxin modifies or inhibits a specific molecule in neurons that help process and transmit information.
sim120504 runs
infromation processing neurophysiology biology
115407
#6

COVID-19 Simulator

This simulator looks at the spread of COVID-19 (Coronavirus) through a city. You can implement poli ... Read more
This simulator looks at the spread of COVID-19 (Coronavirus) through a city. You can implement policies, change assumptions about the disease and see the impacts in realtime.
sim105084 runs
Biology Science Education COVID-19 Coronavirus
98527.9
#7

Apterous Genetics

Apterous is an allele that results in a fly without wings. Wild-type variants have normally function ... Read more
Apterous is an allele that results in a fly without wings. Wild-type variants have normally functioning wings. The goal of this simulation is to determine the pattern of inheritance for the apterous phenotype. Is apterous dominant or recessive? Sex-linked or autosomal? Complete, incomplete, or codominant?
sim247872 runs
Genetics
87826.6
#8

Cellular Respiration Accounting Model

The purpose of the model is to understand how glucose is metabolized, and how the energy stored in i ... Read more
The purpose of the model is to understand how glucose is metabolized, and how the energy stored in its chemical bonds is transfered.
sim497703 runs
cellular respiration aerobic respiration ATP biology
83346.8
#9

Growth Factors, Cyclins, and Cancer

Explores the feedback loops that regulate the cell cycle. Model focuses on manipulating stimuli (gro ... Read more
Explores the feedback loops that regulate the cell cycle. Model focuses on manipulating stimuli (growth factors), to stimulate the cell cycle feedback loops.
sim223014 runs
growth factors cyclins cell cycle cancer
70925.8
#10

Lactase with Variable Sample Sizes

Arrayed Lactase Model
sim640663 runs
Lactase array sample size biology
57086.1
#11

Lactose Operon: An Inducible System

In this simulation users explore the negative feedback system of the Lactose Operon found in bacteri ... Read more
In this simulation users explore the negative feedback system of the Lactose Operon found in bacteria. Lactose induces the system by inhibiting and inhibitor.
sim116863 runs
Inhibition negative feedback biology lactose operon
55977.3
#12

Vacation

Do you ever feel like work is taking over your life? Burnout is generally characterized as a state o ... Read more
Do you ever feel like work is taking over your life? Burnout is generally characterized as a state of mental and physical exhaustion resulting in low productivity and de-personalization and is most likely caused by prolonged stress that does not dissipate. There are many different aspects that affect both the building and dissipation of burnout. This model focuses on workloads and vacations to see how they contribute to both your level of burnout and productivity. Use this model to ask questions about your workload and any benefits you would receive from taking a vacation. What happens when you suddenly have a bigger workload? What happens when work piles up? Does vacation increase or decrease your stress levels?
sim24648 runs, 588 downloads
Download Model
Vacation burnout stress productivity workload
50951.1
#13

Neurophysiology and Neurotoxicity

The main dependent variable measured in the model is the membrane potential (millivolts) of a motor ... Read more
The main dependent variable measured in the model is the membrane potential (millivolts) of a motor neuron and the muscle fiber it innervates. You will be able to add excitatory and inhibitory neurotransmitters, and compare how neurotransmitters modulate the electrical impulses of the motor neuron and the muscle fiber. Additionally, you will be able to compare the effects of four neurotoxins: Tetrodotoxin, botulinum toxin, sarin nerve gas, and VX. While extremely lethal, these toxins are very instructive in understanding neurons because of the specific way the toxins act. Each toxin modifies or inhibits a specific molecule in neurons that help process and transmit information.
sim46458 runs
Neurophysiology toxins sarin VX TTX
45152.9
#14

College Loans

Each year, the cost of a college education continues to rise and more and more students must turn to ... Read more
Each year, the cost of a college education continues to rise and more and more students must turn to student loans to complete their education. But as graduates leave college to embark on their careers, they face an almost Sisyphean struggle with student debt, forever facing an uphill battle while carrying a heavy burden, only to find they are getting nowhere! Whether you are graduating from college or just entering, we hope this model will enable you to better understand student loans and help plan for your future.
sim25922 runs, 898 downloads
Download Model
Student loans loans college interest repayment
45073.7
#15

Evolution and Natural Selection

sim267340 runs
44478.1
#16

Model 2. Drug Transporters

This simulation shows the location and functioning of the major clinically important drug transporte ... Read more
This simulation shows the location and functioning of the major clinically important drug transporters in the : gastrointestinal membrane; renal tubular membrane; and the membranes of the hepatocyte. Simulations demonstrate their functioning after oral and intravenous doses of a drug substrate
sim40577 runs
drug transporters efflux uptake drug absorption
42870.4
#17

Enzyme Diversity

sim350772 runs
enzyme biology substrate pepsin indicators
42439.1
#18

Zombie Apocalypse

This is our first model in the From Imagination to Simulation series. It is a nod to the Halloween s ... Read more
This is our first model in the From Imagination to Simulation series. It is a nod to the Halloween season and investigates a zombie apocalypse! Our fascination with zombies continually grows with the help of movies, TV shows, and books that give a wide range of zombie possibilities. But what are the dynamics behind a zombie epidemic? This model will specifically look at the spread of a zombie outbreak and examine some of the variables that help and hinder the rate of infection. We hope you will continue to see the benefits and versatility of Systems Thinking and enjoy our new series, From Imagination to Simulation! Continue to ponder those out-of-the-ordinary problems. They may seem unrealistic, but perhaps some of their dynamics may resonate with reality. Check out our zombie apocalypse model to see if there is any chance for human survival!
sim17110 runs, 610 downloads
Download Model
Systems Thinking zombies epidemic disease susceptible
39617.4
#19

Oral Absorption

This model is based on first order absoprtion in a 1-compartment model
sim36800 runs, 90 downloads
Download Model
Drug Absoprtion Bioavailability Bioequivalence
36659
#20

Intravenous Infusion

This model demonstrates the pharmacokinetic characteristics of constant continuous drug administrati ... Read more
This model demonstrates the pharmacokinetic characteristics of constant continuous drug administration.
sim17857 runs, 56 downloads
Download Model
drug pharmacokinetics intravenous infusion zero order input constant continuous drug administration
35052.9
#21

Oxytocin and Child Birth

sim173243 runs
33194.6
#22

Population dynamics of white footed mouse

sim674092 runs
32322.8
#23

Evolution of Antibiotic Resistance Simulation

Evolution of Antibiotic Resistance Simulation. This model tracks the accumulation of 40 colonies of ... Read more
Evolution of Antibiotic Resistance Simulation. This model tracks the accumulation of 40 colonies of bacteria. The main purpose of the model is to show that new adaptations are not caused by an environmental factor, like antibiotics. Rather, new adaptations are the selection of available variations. In this model you can increase variations by increasing the UV dose. The UV dose increases the mutation rate with a Monte Carlo function.
sim104609 runs
Biology Science Ecology Education
29567.4
#24

Cellular Respiration Inquiry

Model of the dynamics of the metabolism of one mole of glucose. Randomness is built into the computa ... Read more
Model of the dynamics of the metabolism of one mole of glucose. Randomness is built into the computations.
sim78764 runs
metabolism respriation ATP biology
27849.8
#25

Lac Operon with Monod Bump

sim152916 runs
Lac Operon Gene Regulation mRNA
26653.7
#26

Genotyping with Electrophoresis

sim35213 runs
biology inheritance DNA restriction enzyme
25722
#27

Photosynthesis Simulation with Variance

sim208105 runs
24298.7
#28

Mulitple Bolus Injections Pharmacokinetics

This model shows the typical plasma concentration profile associated with the administration of seve ... Read more
This model shows the typical plasma concentration profile associated with the administration of several doses of a drug over time. It demonstrates the determinants of the fluctuation in the plasma concentrations, the accumulation of the drug over the course of therapy and the resting steady state plasma concentrations.
sim14163 runs, 52 downloads
Download Model
drug pharmacokinetics multiple doses multiple intravenous bolus injections
24094.8
#29

Limiting Nutrients in Aquatic Ecosystems

Experiment with a variety of nutrients that are limited by different degrees in four different ecosy ... Read more
Experiment with a variety of nutrients that are limited by different degrees in four different ecosystems.
sim82072 runs
limiting nutrients ecosystem biology logistic growth
22352.2
#30

Photosynthesis with Variable Sample Sizes

Sample sizes of Photosynthesis stocks in an array
sim86160 runs, 80 downloads
Download Model
22216.6
#31

iSDG Tanzania

sim31105 runs, 1 download
SDG policy integration coherence simulation
22059.1
#32

Guppy Evolution

sim121944 runs
evolution biology genes
21897.4
#33

2019 Step1

Step1
sim36313 runs
intravenous oral theophylline
21287.6
#34

Administration routes

observe three type of plasma concentration curve, and combine three of them
sim10822 runs
Pharmacokinetics intra venous bolus div p.o.
21066.4
#35

Multiple Oral Doses Pharmacokinetics

Most commonly people take oral doses of a drug over an extended period. This model demonstrates the ... Read more
Most commonly people take oral doses of a drug over an extended period. This model demonstrates the unique plasma concentration profile associated with this type of drug administration. The model assumes first-order drug absorption with no lag time. Simulations can be carried out to observe how the rate and extent of absorption (bioavailability) affect the profile.
sim11926 runs, 48 downloads
Download Model
multiple oral doses interactive pharmacokinetics drug bioavailability
19568.7
#36

Predator-Prey-LevelC

sim24013 runs, 42 downloads
Download Model
ecosystem predator prey oscillation balance
19071.9
#37

Evolution of LAP Allele in Mussels

sim62150 runs
Evolution Natural Selection Cline
18359.5
#38

SIR COVID-19 Coronavirus Simulation

sim14635 runs
Environment Biology Science Education SIR
18349.1
#39

Lotka-Volterra Predator-Prey Model

Explore my favorite aspect of system dynamics and a historic example. The homeostasis generated by t ... Read more
Explore my favorite aspect of system dynamics and a historic example. The homeostasis generated by the interconnections of a negative feedback loop governs much of life.
sim161091 runs
negative feedback loop Lotka-Volterra homeostasis predator-prey
18095.8
#40

Route21

Administration routes
sim13373 runs
Biology Science Education pharmacokinetics simulation
17955.2
#41

Closed Loop

Mininimal closed-loop model of the cardiovascular system
sim92527 runs
16728.5
#42

White-Eyed Genetics

White-eyed is an allele that results in a fly white eyes. Wild-type variants have red eyes. The ... Read more
White-eyed is an allele that results in a fly white eyes. Wild-type variants have red eyes. The goal of this simulation is to determine the pattern of inheritance for the white-eyed phenotype. Is yellow body dominant or recessive? Sex-linked or autosomal? Complete, incomplete, or codominant?
sim119292 runs
Genetics
15157.4
#43

Automation

Innovation often raises concerns about job losses, increasingly so in the past century with widespre ... Read more
Innovation often raises concerns about job losses, increasingly so in the past century with widespread automation and advanced artificial intelligence. Should we start to fear for our job security or will the creative potential in society maintain the labor force? Explore this model to see some of the interesting possibilities!
sim5719 runs, 389 downloads
Download Model
Automation job loss AI artificial intelligence labor force
14121.4
#44

Pharmacokinetics: An IV Injection on a Two Compartment Model

This model shows the profile of a drug after an intravenous injection when the drug displays two com ... Read more
This model shows the profile of a drug after an intravenous injection when the drug displays two compartment characteristics
sim15570 runs, 49 downloads
Download Model
drug pharmacokinetics IV two compartment model
13967.9
#45

Diffusion of a Spherical Cell

Why are cells small? This model allows users to see how the size of a sphere affects the rate of dif ... Read more
Why are cells small? This model allows users to see how the size of a sphere affects the rate of diffusion.
sim114752 runs
diffusion surface area volume radius
12697.5
#46

COVID-19 Model

This simulator walks the user through a model showing the spread of the COVID, or Corona Virus throu ... Read more
This simulator walks the user through a model showing the spread of the COVID, or Corona Virus through a city. You can implement policies, change assumptions about the disease and see the impacts in realtime.
model9796 downloads
Download Model
Biology Science Education COVID-19 Corona Virus
12135
#47

Transformation Simulation

Simulation allows students to test the transformation principle. Two major goals of the experiment a ... Read more
Simulation allows students to test the transformation principle. Two major goals of the experiment are: 1. Allow users to see that supernatant from heat-killed bacteria can transform the genes of another bacterium. 2. What transforms the inheritance of the bacteria is DNA, not RNA or proteins.
sim109496 runs
transformation DNA biology
11900.9
#48

Dosing regimen for renal failure

Dosing regimen for renal failure
sim9182 runs
Biology Science Education pharmacokinetics simulation
11675.8
#49

Thyroid Hormone - Negative Feedback

sim51546 runs
negative feedback thyroid hormone metabolism biology
11475
#50

Nonlinear Pharmacokinetics and Phenytoin

Nonlinear or capacity limited pharmacokinetics can occur whenever a process involved in the absorpti ... Read more
Nonlinear or capacity limited pharmacokinetics can occur whenever a process involved in the absorption, distribution or elimination of a drug becomes saturated. This model demonstrates nonlinear elimination (metabolism) using phenytoin as the model drug. Specifically, it demonstrates how increasing doses of the drug produce disproportionate increases in the plasma concentration. It also demonstrates how the model parameters, Km and Vmax influence of the plasma concentration -time profile.
sim6226 runs, 38 downloads
Download Model
nonlinear pharmacokinetics capacity limited elimination drug phenytoin
10983.9
#51

Tolerance-Nicotine- Hypothetical Antagonist

Tolerance may be defined as a process that results in a reduction in the response to a specific drug ... Read more
Tolerance may be defined as a process that results in a reduction in the response to a specific drug concentration following repeated drug exposure. One model for tolerance assumes that the drug produces a hypothetical metabolite that opposes its action.
sim10129 runs, 21 downloads
Download Model
Tolerance Nicotine Hypothetical Antagonist
10442.7
#52

Recombination and Gene Linkage

sim95359 runs
10396.5
#53

Understanding Restrictive and Nonrestrictive Hepatic Clearance

Many drugs are removed from the body by metabolism in the liver. A drug's hepatic clearance is a me ... Read more
Many drugs are removed from the body by metabolism in the liver. A drug's hepatic clearance is a measure of the liver's ability to metabolize a drug. This simulation demonstrates the characteristics of high extraction (nonrestrictive clearance, low extraction (restrictive clearance and intermediate clearance.
sim7018 runs
drug metabolism clearance elimination restrictive clearance
9844.31
#54

Water Potential and Osmosis

Factors that affect the flow across a semi-permeable membrane.
sim281921 runs
9492.25
#55

Understanding the Measles Outbreak

The current 2019 measles outbreak is the highest since the early '90s and is drawing much attention ... Read more
The current 2019 measles outbreak is the highest since the early '90s and is drawing much attention from the media and the public. This model walks investigates how measles spreads in a population and what policies work best for reducing that spread.
sim5022 runs, 343 downloads
Download Model
Measles vaccine infectious disease quarantine WOM
9315.75
#56

Populations-LevelC

The behavior over time of a population limited by density-dependent factors is called logistic growt ... Read more
The behavior over time of a population limited by density-dependent factors is called logistic growth. You will be simulating a model of logistic population growth. You'll be able to change factors that address how fast an animal population grows, how long individuals in the population live on average, and how much area the population has available. See if you can vary the shape of the logistic curve, or create something different.
sim11717 runs, 53 downloads
Download Model
populations logistic
9278.8
#57

H1N1 Flu Outbreak

What is most effective in controlling the outbreak of a flu virus in schools? Is it better to vaccin ... Read more
What is most effective in controlling the outbreak of a flu virus in schools? Is it better to vaccinate or stay home? Use this Learning Lab to understand how infectious disease spreads and why the World Health Organization signaled the 2009 H1N1 (also called “swine flu”) outbreak as a pandemic.
sim4760 runs, 270 downloads
Download Model
Environment Biology Education Flu outbreak
8807.32
#58

Multiple Intermittent Infusions Pharmacokinetics

The model shows the unique plasma concentration-time profile associated with the administration of a ... Read more
The model shows the unique plasma concentration-time profile associated with the administration of a drug using multiple short infusions. It demonstrates the influence of the duration of the infusion and allows the user to practice the calculation of a suitable dose and dosing interval to achieve desired peak and trough plasma concentrations of a drug.
sim4382 runs, 29 downloads
Download Model
Multiple intermittent infusions aminoglycoside infusion drug interactive pharmacokinetics
8481.42
#59

Sigmoidal Emax Model of Drug Response

This is the model that is most commonly used to for the time course of drug effects in man. It assum ... Read more
This is the model that is most commonly used to for the time course of drug effects in man. It assumes that the response is driven by the blood or plasma concentrations of the drug. When the model parameters are known, it can be used to predict response at anytime time after any dose.
sim7405 runs, 50 downloads
Download Model
Pharmacodynamic Drug Sigmoidal Emax Emax
8206.67
#60

Choosing the Future

Users can run 3 long term scenarios for the Canadian economy featured in Managing without Growth (2n ... Read more
Users can run 3 long term scenarios for the Canadian economy featured in Managing without Growth (2nd edition) and create their own
sim5159 runs
economic growth post-growth no growth sustainable prosperity environment
8187.27
#61

Model 1. Introduction to PK and PD

This model allows users to use trial and error to identify appropriate doses of a drug for IV, oral ... Read more
This model allows users to use trial and error to identify appropriate doses of a drug for IV, oral and other extravascular routes of administration
sim46029 runs
Pharmacokinetics Pharmacodynamics Therapeutic Range
7962.84
#62

The Power of The Missing Middle

Systems Thinking at Large takes a closer look at the suprising win for Trump. Focusing on the missi ... Read more
Systems Thinking at Large takes a closer look at the suprising win for Trump. Focusing on the missing middle population and their possible power in the voting booth.
sim2601 runs, 234 downloads
Download Model
Trump missing middle vicious cycle storytelling manufacturing jobs
7135.05
#63

Pharmacokinetics: An IV Injection in a 1-Compartment Model

sim28276 runs, 81 downloads
Download Model
6812.78
#64

Housing Supply and Demand

Use this learning lab to investigate the housing crisis. Play with interest rates as if you are Chai ... Read more
Use this learning lab to investigate the housing crisis. Play with interest rates as if you are Chairman of the Federal Reserve and see the impact on housing supply and demand. What happens when banks relax mortgage requirements and more people qualify to buy homes?
sim3402 runs, 583 downloads
Download Model
Modules finance debt economics housing demand
6757.82
#65

Temperature Control

Conduct experiments and try to maintain a constant temperature in a house that uses a climate contro ... Read more
Conduct experiments and try to maintain a constant temperature in a house that uses a climate control system. Turn on and off the Proportional and Integral controllers that drive the heat pump. Experiment with different outside temperatures, and different thermostat settings. See what happens when you change the house's insulation by adjusting the temperature loss constant.
sim3861 runs, 351 downloads
Download Model
Temperature proportional integral controller Newton's law heat pump
6707.71
#66

interval

dosing interval
sim4798 runs
Biology Science Education pharmacokinetics simulation
6417.21
#67

Circadian Clock in the Mouse

Transcriptional Translational Feedback Loop in the Mouse
sim25451 runs
Mouse Circadian Clock
6287.12
#68

The dynamics of photosynthesis - variable sample size

The dynamics of photosynthesis - variable sample size
sim89766 runs
photosynthesis sample size biology
6107.4
#69

Phenology of the Karner Blue Butterfly

Karner Blue butterfly is an endangered species. Habitat loss and climate change are contributing fac ... Read more
Karner Blue butterfly is an endangered species. Habitat loss and climate change are contributing factors to the reduction in the butterflies' population sizes. Climate change can alter the timing of lifecycles. When climate change disproportionally affects the timing of life cycles of species in an ecosystem asynchrony within a food web occurs.
sim9427 runs
asynchrony timing phenology climate change butterfly
6075.11
#70

Tryptophan Operon: A repressible system

sim66694 runs
6033.44
#71

Dosing regimen for renal failure

compare plasma concentration in renal failure, plan the dosing regimen in renal failure
sim3579 runs
Pharmacokinetics creatinine clearance Scr Clcr aminoglycoside
5986.25
#72

Predator-prey-biomass-LevelA

Predator/Prey/Biomass Level A: All Together Now: Predator, Prey and Plants This lesson allows st ... Read more
Predator/Prey/Biomass Level A: All Together Now: Predator, Prey and Plants This lesson allows students to explore the interactions of two animal populations (wolves and moose) and plants within an ecosystem. The populations and the plants rise and fall (oscillate) over time as they interact and impact one another.
sim7830 runs, 21 downloads
Download Model
ecosystems oscillation
5772.28
#73

Predator-prey-LevelB

Level B: Wild Things: Interacting Populations This lesson allows students to explore the interactio ... Read more
Level B: Wild Things: Interacting Populations This lesson allows students to explore the interactions of two animal populations (predator and prey) within an ecosystem. Their populations can rise and fall (oscillate) over time as they interact and impact one another.
sim6075 runs, 20 downloads
Download Model
ecosystem predator prey oscillation
5758.14
#74

Guns At School

This interface explores the public policy issue of gun violence at schools. As a policymaker, you c ... Read more
This interface explores the public policy issue of gun violence at schools. As a policymaker, you can explore different initiatives to see which are most effective at reducing this violence.
sim7382 runs
Guns Schools Public Policy Violence Bullying
5663.24
#75

Simple Genetics

sim96208 runs
5645.78
#76

Predator-Prey-Biomass-LevelC

Level C: Eat and Be Eaten: Prey as Predator, Predator as Prey This model explores a moose and wol ... Read more
Level C: Eat and Be Eaten: Prey as Predator, Predator as Prey This model explores a moose and wolf population. A predator/prey relationship is present, as with Lesson 4, but now the moose have a food source, creating a more realistic representation of the ecosystem. Students take on the role of wildlife manager and control hunting policies for both predator and prey populations. The default simulation behavior for prey, predators, and biomass is oscillation. Depending on policy decisions, a variety of results occur.
sim4284 runs, 65 downloads
Download Model
science ecosystem oscillation predator prey
5642.62
#77

Headcount Strategy

Explore a consulting firm’s headcount strategy. Understand the relationship between growth rates, pr ... Read more
Explore a consulting firm’s headcount strategy. Understand the relationship between growth rates, promotion times, headcount pyramid ratios, and attrition rates. This model is based on actual work that was done with a very well-known consulting company (here, code-named TWBC, Inc.). The firm's strategic goals were well-articulated, and each made sense when written down in a list on a piece of paper. However, when subjected to the more rigorous, dynamic scrutiny that an iThink modeling effort provides, the goals (as is too often the case) turned out to be in conflict with one another--stimulating actions that worked at cross-purposes. Efforts to achieve one goal drove the firm farther away from achieving the others. The subsequent analysis conducted with the model also pointed the way toward resolving the internal strategic inconsistencies and putting the firm back onto a strategically sound growth path.
sim2174 runs, 337 downloads
Download Model
Headcount employees growth manager consultant
5138.5
#78

Dairy Cows

Agriculture offers many modeling opportunities. In this Systems in Focus, we look at the life cycle ... Read more
Agriculture offers many modeling opportunities. In this Systems in Focus, we look at the life cycle of a dairy herd, including milk production. This model could be used as the basis for methane production control, trade agreements about milk and how that impacts herd size, increasing production with demand, etc. Visit https://iseesystems.com/resources/systems-in-focus/agriculture/ for more information.
model3952 downloads
Download Model
Systems in Focus agriculture cows dairy
4852.49
#79

Pattern with recessive single band

sim77043 runs
genetics
4556.12
#80

Steady State in Freshwater Ecosystems

sim29154 runs
4370.22
#81

COVID-19: Vertical Isolation in Brazil

Does the policy of vertical isolation allow a country to reopen its businesses and schools without i ... Read more
Does the policy of vertical isolation allow a country to reopen its businesses and schools without increasing COVID-19 cases or deaths? This simulator explores the outcomes of horizontal isolation (what we're doing now) and vertical isolation (only isolate the sick and the elderly).
sim4430 runs
Biology Science Education COVID-19 coronavirus
4261.67
#82

Populations-LevelA

Part of the osillation series, this simulation explores populations with a carrying capacity (one th ... Read more
Part of the osillation series, this simulation explores populations with a carrying capacity (one that does not oscillate because it has just one stock).
sim9040 runs, 44 downloads
Download Model
population ecology
4251.46
#83

Irreversible Drug Effects - Proton Pump Inhibitors

Some drugs act by binding covalently to their receptors. As a result, the target is destroyed and it ... Read more
Some drugs act by binding covalently to their receptors. As a result, the target is destroyed and its function returns only when it has been replaced by newly synthesized product. The target may be a protein, DNA, an enzyme, or a cell at any stage of development. This model has been applied to the action of the proton pump inhibitors, which bind to and destroy the H+,K+-ATPase pumps in the parietal cells of the gastric mucosa. Normal proton secretion is restored only when the pumps are replaced by newly synthesized functioning pumps (i.e., the usual turnover time of the system).
sim2054 runs, 12 downloads
Download Model
Pharmacodynamic Irreversible Drug Effects Proton Pump Inhibitors PPI Response Model
4073.2
#84

Limits to Growth Archetype

Shifting loop dominance in a limits-to-growth archetype is examined using the Hayward/Boswell Loop I ... Read more
Shifting loop dominance in a limits-to-growth archetype is examined using the Hayward/Boswell Loop Impact Method.
sim2031 runs, 183 downloads
Download Model
Business Loop Dominance Limits to Growth Shifting loop dominance Urban Dyanmics
4043.24
#85

Animal Temperature

Explore the laws of thermodynamics with this animal temperature model. As you experiment, think abo ... Read more
Explore the laws of thermodynamics with this animal temperature model. As you experiment, think about animal adaptations and consider the following: What problems do small animals face compared to large animals in hot and cold environments? What problems do cold-blooded (poiklothermic) animals face compared to warm-blooded (homeothermic) animals? What is it that insulation really does for animals? The story behind this model is explained in a chapter of Tracing Connections
sim1612 runs, 120 downloads
Download Model
Thermodynamcis adaptation poiklothermic homeothermic Warm-blooded
3951.34
#86

Macromodel

Model for the public policy testing
sim15129 runs, 45 downloads
Download Model
3934.77
#87

Change the dosing interval

interval & dosing, regularly or irregularly
sim2920 runs
Pharmacokinetics dosing interval irregular interval TMU Hara
3880.83
#88

Pulmonary Edema

This model predicts collection of fluid in the lungs.
sim13985 runs
3620.69
#89

Urban Business Expansion

The business sector of the Three Stock Urban Dynamics model is examined using the Hayward/Boswell Lo ... Read more
The business sector of the Three Stock Urban Dynamics model is examined using the Hayward/Boswell Loop Impact Method.
sim1785 runs, 114 downloads
Download Model
Loop Dominance Limits to Growth Shifting loop dominance Urban Dyanmics Loop Impact
3548.5
#90

Transformation Experiment with Controls

Simulation allows users to test the bacterial transformation principle discovered by Frederick Griff ... Read more
Simulation allows users to test the bacterial transformation principle discovered by Frederick Griffith.
sim19008 runs
Biology Science Education transformation DNA
3532.68
#91

Business Cycle Dynamics

Business cycles are a fact of life for many industries. Market demand peaks one year only to plummet ... Read more
Business cycles are a fact of life for many industries. Market demand peaks one year only to plummet a year or two later. In this case study of a semiconductor business, Henk Akkermans, Professor of Supply Network Dynamics at Tilburg University, explores different policy options for order handling, production planning and capacity management to reduce oscillation and improve system performance.
sim1501 runs, 433 downloads
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supply chain semiconductor oscillation. production planning capacity management
3488.87
#92

Sustainable Shrimping

This Learning Environment should help you understand some basic population dynamics and their releva ... Read more
This Learning Environment should help you understand some basic population dynamics and their relevance to policy development for sustainable shrimping practices. While the specific context is shrimping, the concepts learned should be transferable to other harvesting situations (fishing, hunting, tree farming, etc.)
sim3179 runs, 181 downloads
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population dynamics shrimp harvesting
3361.97
#93

Biomass Accumulation Model

Learn to use a simple computer model to predict biomass and carbon storage for any geographical biom ... Read more
Learn to use a simple computer model to predict biomass and carbon storage for any geographical biome. Learn more at www.globe.gov (The GLOBE Program).
sim3228 runs
biomass biomass accumulation carbon cycle globe npp
3226.26
#94

Humanitarian Aid

A look at disaster relief under uncertain local government scenarios. It looks at how long it might ... Read more
A look at disaster relief under uncertain local government scenarios. It looks at how long it might take to establish clean water thru flying in bottled water and constructing wells. There is also the impact on spread of disease and survival due to lack of water. Created by Mark Heffernan and George McDonnel
sim1851 runs, 225 downloads
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Disaster relieft Water Mark Heffernan George McDonnel scenarios
3096.29
#95

HPV and Adaptive Immune Response

sim7917 runs
HPV Antibodies feedback loops vaccine
3043.92
#96

Extended Agrarian Society (from Dynamic Systems)

This model is an extension of the Simple Agrarian Society model from Dynamic Systems. The extensions ... Read more
This model is an extension of the Simple Agrarian Society model from Dynamic Systems. The extensions are to add a CO2 cost to the industrialization, an impact of CO2 on global temperature, an impact of global temperature on drought frequency, and impact of drought on food production and an impact of global temperature on polar sea ice.
model1398 downloads
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population agriculture industrialization climate ice sheet
3039.8
#97

Evolution with Heterozygous Advantage

Evolution of Populations: Genetic Drift, Natural Selection, and Mutations
sim7602 runs
evolution natural selection genetic drift
2981.24
#98

PEOPLE-EXPRESS

A SIMPLIFIED VERSION OF PEOPLE EXPRESS GAME FOR CLASSROOM OR GROUP USE
sim6157 runs
Business Economics Education
2980.1
#99

Simple Global Carbon Cycle Model

The Global Carbon Cycle Model is a 5-box model, which includes five of the major carbon pools (atmos ... Read more
The Global Carbon Cycle Model is a 5-box model, which includes five of the major carbon pools (atmosphere, plants, oceans, soils, and fossil fuels), and the fluxes between them. Use the Global Carbon Cycle Model to explore how carbon moves throughout the Earth system, how different pools and fluxes interact, and the impacts of human actions on the carbon cycle. Learn more at www.globe.gov (the GLOBE Program).
sim8851 runs
carbon cycle carbon global globe simple
2975.83
#100

2019 Step2

dosing interval
sim9368 runs
regular irregular
2971.35
#101

Airport Runway Capacity

Examine the implications of an increasing number of landing airplanes on a fixed capacity runway.
sim1403 runs, 334 downloads
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Reengineering discrete modeling queues iThink process improvement
2861.72
#102

COVID-19: Role of hospitals, soc. dist., and vaccines

sim3538 runs
Environment Biology Business Technology Science
2508.72
#103

Catastrophic Regime Change in Aquatic Ecosystems

sim67269 runs
Ecology
2476.12
#104

Stella Architect B.M. Sample

Este modelo es un primer intento de utilizar el "Business Canvas" desarrollado por Alexander Osterwa ... Read more
Este modelo es un primer intento de utilizar el "Business Canvas" desarrollado por Alexander Osterwalder e Yves Pigneur, para explicar su carácter sistémico mediante la simulación de un modelo de negocio genérico utilizando Stella Architect. El objetivo principal es mostrar el vínculo entre los conceptos del pensamiento sistémico y la práctica del "Systems Dynamics" con el ampliamente difundido "Business Canvas". En la narrativa utilizada para describir la construcción del diagrama "Stock & Flow", se denomina entre parentesis el tipo de componente (Stock, Flow, Converter, o Conector) correspondiente a los principales elementos del modelo de negocio. La simulación permite visualizar la naturaleza sistémica de un modelo de negocio representado mediante el "Business Canvas".
sim559 runs, 127 downloads
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Stella Architect Business Canvas Modelos de Negocios Alex Osterwalder Simulación
2448.11
#105

Global Carbon Cycle Model with Feedbacks

The Global Carbon Cycle Model with Feedbacks builds on the Simple Global Carbon Cycle Model by inclu ... Read more
The Global Carbon Cycle Model with Feedbacks builds on the Simple Global Carbon Cycle Model by including ecosystem feedbacks as well as new parameters such as CO2 and temperature effects, more carbon pools, and marine biota. Use this model to explore how carbon moves through the Earth system, how the pools and fluxes interact, and how human actions can impact the carbon cycle. Learn more at www.globe.gov (The GLOBE Program) Use this model to explore how carbon moves through the Earth system, how the pools and fluxes interact, and how human actions can impact the carbon cycle. Learn more at www.globe.gov (The GLOBE Program)
sim4633 runs
carbon carbon cycle global globe feedbacks
2446.44
#106

Financial instability

by Crelis
Market-capitalism typically goes through cycles of expansion and contraction. Every now and then, th ... Read more
Market-capitalism typically goes through cycles of expansion and contraction. Every now and then, these common economic cycles go off the hinges. They become unstable and can lead to recessions, crises and depressions—phenomena that economists typically look to exogenous forces to explain. Alternative, mostly Marxian and Keynesian, explanations for the instabilities have been sought within the structure of the economic system itself. One such explanation is provided by Steve Keen in his Goodwin-Minsky model. The model effectively mimics the dynamics of key indicators prior to, during and after the 2007/08 crisis. However, the model is also over-specified, highly sensitive to initial conditions and therefore more difficult to convey. In line with George Box’s plea for parsimony, this paper presents a more straightforward version of Keen’s model that remains consistent with its fundamental behaviour. The model also illustrates the potential for further dialogue between Marxian economics and system dynamics.
model841 downloads
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Financial instability Karl Marx Richard Goodwin Hyman Minsky Steve Keen
2377.98
#107

Energy Demand Lab

This simple model explores the demand dynamics for a state's energy usage. For three sectors (reside ... Read more
This simple model explores the demand dynamics for a state's energy usage. For three sectors (residential, industrial, and agricultural) you can adjust the size of initial user base, the growth rate for the number of users, and the rate for the change in demand per user.
sim1056 runs, 400 downloads
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Energy residential industrial agricultural energy usage
2295.85
#108

COVID-19 Model By Age

This models the COVID-19 pandemic as an SEIR model disaggregated by age. DIfferent ages have differ ... Read more
This models the COVID-19 pandemic as an SEIR model disaggregated by age. DIfferent ages have different contact rates, death rates, and conformance to social distancing. A thrid-order material delay is used to create the distribution for the tie to become infected and the time to recover.
model1972 downloads
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Biology Science Education COVID-19 Coronavirus
2269.43
#109

Model 21. Emax Model of Drug Response With an Effect Compartment

This model demonstrates how an effect compartment can be added to a pharmacokinetic model to accommo ... Read more
This model demonstrates how an effect compartment can be added to a pharmacokinetic model to accommodate a delay in drug response caused by a slow distribution of a drug to its site of action. The simulation also explains hysteresis
sim1888 runs, 27 downloads
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Drug Hysteresis Effect Compartment Pharmacodynamics
2201.04
#110

Thinking About Drinking

What happens WHEN someone you know drinks? That depends, on the amount of alcohol consumed, the time ... Read more
What happens WHEN someone you know drinks? That depends, on the amount of alcohol consumed, the timeframe, along with a number of personal characteristics. Indeed, the level of alcohol which builds up in a person's bloodstream can vary enormously.
sim1747 runs, 33 downloads
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Biology Science Education alcohol teen drinking
2161.03
#111

Limited Enthusiasm Model of Church Growth

A model of the growth of the Christian Church in periods of religious revival. The growth mechanism ... Read more
A model of the growth of the Christian Church in periods of religious revival. The growth mechanism is similar to the spread of an infectious disease.
sim1441 runs, 45 downloads
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Church growth Revival Religion Epidemiology Enthusiasts
2138.66
#112

Dynaville

Dynaville simule l'évolution des habitants d'un territoire à un horizon de 10 ans (ménages, déplacem ... Read more
Dynaville simule l'évolution des habitants d'un territoire à un horizon de 10 ans (ménages, déplacements...), selon différents scénarios de logements, d'emplois et d'évolution de son attractivité.
sim1188 runs
attractivité territoire habitants démographie politique de logements déplacements
2071.37
#113

traffic congestion

Explores the dynamics of road use and road construction.
model3130 downloads
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traffic urban planning congestion
2045.21
#114

Integrated Population System

This model is a second extension of the Simple Agrarian model from Dynamic Systems that modifies the ... Read more
This model is a second extension of the Simple Agrarian model from Dynamic Systems that modifies the simple agrarian society model to include drought, industry produced CO2 and ice sheet dynamics. Primarily this is published as a test of porting from Stella 10.1 and learning how the new Stella Online operates. Several of the converter weights have been fine tuned to provide a better behaved model than the first adaptation. At some point a user interface and story will be added and the starting conditions calibrated to approximate treating Earth as an industrialized, agrarian society.
model813 downloads
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population agriculture industrialization climate ice sheet
1998.52
#115

HPV with Influenza A Humoral Immunity

Immune response of HPV
sim20441 runs
HPV antibodies biology Immunity
1992.32
#116

Supply Chain Dynamics

Use this model to explore the implications of supplier, producer, and consumer attributes on overall ... Read more
Use this model to explore the implications of supplier, producer, and consumer attributes on overall supply chain performance.
sim1506 runs, 398 downloads
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Supply Chain inventory main chain reengineering
1921.34
#117

Extinction Vortex

sim34845 runs
1888.52
#118

Tesing Unknown Enzymes

sim180862 runs
enzymes
1804.54
#119

COVIDGlobal

Projections for COVID-19 pandemic across the globe
sim5021 runs
COVID-19 Pandemic
1790.66
#120

Beta Cell Simulation - Split story

sim40274 runs
1761.38
#121

System Dynamics of Carbon Budget

Simulation of the system dynamics of the global carbon dioxide budget based on the work on systems d ... Read more
Simulation of the system dynamics of the global carbon dioxide budget based on the work on systems dynamics based on John Sternman (MIT) and Krytyna Stave (University of Nebraska)
sim14470 runs
system dynamics carbon climate
1704.22
#122

macrolab2017

sim6574 runs
1682.86
#123

Health Policy Management Flight Simulator

by Shamim
This is a basic health policy simulator that allows the user a policy lever on where to prioritise h ... Read more
This is a basic health policy simulator that allows the user a policy lever on where to prioritise health care spending.
sim2970 runs
health systems shifting boat
1674.28
#124

Spring-LevelB

Level B: Exploring Springs: A Little Bounce in the World Students explore a simple spring simulat ... Read more
Level B: Exploring Springs: A Little Bounce in the World Students explore a simple spring simulation to see how springs behave, given different characteristics. Students can change the springiness (spring constant), the resistance, a mass at the end of the spring, and the amount of push or pull.
sim3390 runs, 8 downloads
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Science
1670.74
#125

Story of the Month Reissue: Deficit

Examines the often-confused concepts of deficits versus surpluses and tax cuts versus tax rebates.
sim874 runs, 82 downloads
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tax cuts tax rebates deficit surplus social security
1604.69
#126

Logistic Growth Model and the Butterfly Effect

Model allows users to test the starting population size (N), the carrying capacity of the populatio ... Read more
Model allows users to test the starting population size (N), the carrying capacity of the population (K), and the intrinsic rate of growth (r max). Iterations are discrete, not continuous.
sim3347 runs
logistic growth carrying capacity
1575.08
#127

Weight Loss Sim

by Corne
This simulation gives the user the ability to specify their own current condition (weight, age, heig ... Read more
This simulation gives the user the ability to specify their own current condition (weight, age, height etc.), choose their exercise regime and eating plans. The simulator then gives a projection for the user's weight for the next year (at a weekly resolution). Please take note that most of the pictures are navigation buttons to different screens, so remember to click on the pictures. I have personally used this simulator to successfully lose more than 20 kg. Hope you find this as valuable as I did. Good luck with your weight journey!
sim3205 runs
Weight loss Health
1546.42
#128

Tolerance- Precursor Pool Model

Tolerance may be defined as a process that results in a reduction in the response to a specific drug ... Read more
Tolerance may be defined as a process that results in a reduction in the response to a specific drug concentration following repeated drug exposure. Tolerance could occur if an endogenous compound that plays an essential role in the response chain becomes depleted during response. This model assumes the drug stimulates the production of a response variable which becomes then becomes depleted.
sim1112 runs, 10 downloads
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Tolerance Pharmacodynamic precurosr pool depletion model
1540.12
#129

Indirect Effect Model 1

Some drugs do not directly produce the measured drug response. Instead they act upstream, and either ... Read more
Some drugs do not directly produce the measured drug response. Instead they act upstream, and either increase or decrease the amount of the entity that directly mediates the response (response variable). Indirect effect Model I can be used for drugs that inhibit the synthesis of the response variable. An example is warfarin which inhibits the synthesis of clotting factors.
sim1298 runs, 18 downloads
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indirect effect warfarin inhibition of kin
1482.15
#130

Predator-prey-biomass-LevelB

Predator/Prey/Biomass Level B: Circles of Interaction: Predator, Prey and Plants This lesson explo ... Read more
Predator/Prey/Biomass Level B: Circles of Interaction: Predator, Prey and Plants This lesson explores predator (wolf), prey (moose), and food (plants) within an ecosystem. Students role-play being a wildlife manager who is doing "on the job" training. The manager controls hunting of prey populations and killing of predators. The default simulation behavior for prey, predators, and food is oscillation.
sim2047 runs, 13 downloads
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oscillation ecosystem
1475.79
#131

BacterialGrowth

Yo listen up, here's the story About a little guy that lives in a blue world And all day and all n ... Read more
Yo listen up, here's the story About a little guy that lives in a blue world And all day and all night and everything he sees is just blue Like him, inside and outside Blue his house with a blue little window And a blue Corvette And everything is blue for him And himself and everybody around 'Cause he ain't got nobody to listen I'm blue da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa I'm blue da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa I have a blue house with a blue window Blue is the color of all that I wear Blue are the streets and all the trees are too I have a girlfriend and she is so blue Blue are the people here that walk around Blue like my Corvette, it's in and outside Blue are the words I say and what I think Blue are the feelings that live inside me I'm blue da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa I'm blue da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa I have a blue house with a blue window Blue is the color of all that I wear Blue are the streets and all the trees are too I have a girlfriend and she is so blue Blue are the people here that walk around Blue like my Corvette, it's in and outside Blue are the words I say and what I think Blue are the feelings that live inside me I'm blue da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa I'm blue da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa Da ba dee da ba daa, da ba dee da ba daa, da ba dee da ba daa
model740 downloads
Download Model
1472.62
#132

The Laundry Detergent Game

Congratulations! You've just been hired by the major grocery chain The Price Shopper as head of mark ... Read more
Congratulations! You've just been hired by the major grocery chain The Price Shopper as head of marketing. Your job is to turn around The Price Shopper's dismal sales of laundry detergent. The big-wigs have given you 12 months and a marketing budget of up to $10,000 per month to spend as you please. They'll decide to keep you, or send you to the cleaners based on how much profit you bring in over the year. Do you think you can make the big MONEY?
sim936 runs, 99 downloads
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system dynamics bass diffusion model marketing
1464.48
#133

Basic Stella Builtins Library

© Will Noyes 2020 This is an educational tool to learn about the commonly used builtin formulas in ... Read more
© Will Noyes 2020 This is an educational tool to learn about the commonly used builtin formulas in Stella. For each formula there is a basic description, a model representation that allows you to control the different inputs, and one or two output graphs that show the result of that formula. If you would like more information on any of these builtins or on any that are not demonstrated here, remember that you can always consult Stella Help.
model974 downloads
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Education Stella Builtin teaching UiB
1441.91
#134

Evolving Bits

Diversity and selection for the basis of evolution. This simple model tries to illustrate these conc ... Read more
Diversity and selection for the basis of evolution. This simple model tries to illustrate these concepts.
sim1595 runs
Diversity Selection Evolution Receptor Antigen
1432.19
#135

Take the Infusion Challenge

Use this model to see if you can use a drug's pharmacokinetic and pharmacodynamic properties to dete ... Read more
Use this model to see if you can use a drug's pharmacokinetic and pharmacodynamic properties to determine the initial rate of drug administration. See if you can identify potential drug-drug interactions and respond when appropriate by making appropriate modifications to the dose.
sim8113 runs
Dosing Drug Pharmacokinetics Constant Continuous Input
1406.88
#136

Transit Compartment of Drug Action

Change image Submit your own comment on the simulation. Share Comment upgrade hosting plan d ... Read more
Change image Submit your own comment on the simulation. Share Comment upgrade hosting plan delete simulation Transit Compartment Model of Drug Response By Sara Rosenbaum Sim URL: https://forio.com/simulate/sarar/transit-compartment-model Sim access:Other authors can download source model Sim plan: Simulate Free Sim stats:This sim has been run 326 times. This simulation was uploaded to Forio Simulate with the isee NetSim software. More information can be found at iseesystems.com. Your Rating: 1 star2 star3 star4 star5 star Average Rating: rating(1) Click here to edit the description A delay in response to a drug can occur when it takes a long time for the drug’s initial effect to be translated into the final response (a long transduction process). The delayed response profile can be captured using a series of transit compartments.
sim731 runs, 31 downloads
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Pharmacodynamics Transit compartment Delayed drug action
1395.78
#137

SysQ

An Introduction to SysQ is our free interactive resource for building and applying Systemic Intellig ... Read more
An Introduction to SysQ is our free interactive resource for building and applying Systemic Intelligence (SysQ). By using this guide, practitioners of systems thinking and adaptive leadership will better understand why systemic intelligence is an essential leadership capacity and how to increase anyone's (or any team’s) ability to apply it. An Introduction to SysQ gives you rapid access to the full suite of systems thinking tools (including the SysQ Questions, trend graphs, archetypes, causal loop and stock & flow diagrams, and simulations) – including when and how to use each! And because the guide is browser based, it works on mobile devices! You can even embed it on your website. We believe you’ll find this resource so useful that you’ll decide it belongs in your browser’s favorite bookmarks! (Currently, it works best on Google applications and devices – Chrome and Android-based devices.)
sim681 runs
systems thinking system dynamics sysq resource guide
1387.77
#138

Systems In Focus: Environment

One of the greatest environmental challenges we face is how to do more with less: Less raw materials ... Read more
One of the greatest environmental challenges we face is how to do more with less: Less raw materials, less pollution, less damage to the environment. This model shows the life-cycle assessment for the aggregate products manufactured and consumed in a firm, an industry, a region, a nation, or the world. It focuses on solid waste, though it would be easy to add air or water pollution generated and energy consumed at each stage.
model991 downloads
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Environment Ecology Renewable Resources Raw Material
1378.47
#139

Abastecimento de Água

Demanda de água gera novos investimentos em infraestrutura de abastecimento
diagram1394 downloads
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demanda de água abastecimento urbano investimentos
1367.14
#140

Turchin’s Metaethnic Frontier Theory of Imperial Growth

A country builds its empire by attacking its neighbours and taking over both their land and their pe ... Read more
A country builds its empire by attacking its neighbours and taking over both their land and their people. The larger the empire becomes, the more resources they have available to take further territory by force. However the further they expand, the harder they find it to keep expanding due to the geographical and organisational logistics involved. Additionally the empire finds it harder to maintain social cooperation among its people, its asabiya.
sim317 runs, 78 downloads
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Turchin Empire Collapse Collins Geopolitical
1351.49
#141

Salmon Life Cycle Simulator

sim1287 runs
Pacific salmon life cycle modeling water temperature stream flow
1342.35
#142

Campus sexual assault

A very simple, one stock, simulation of campus sexist attitudes toward rape and initimate partner vi ... Read more
A very simple, one stock, simulation of campus sexist attitudes toward rape and initimate partner violence. The model was originally developed in 1998 and later translated into Stella. The model has a number of modeling errors, but at the time, proved useful for gaining insight into the dynamics of the system and developing an innovative prevention program.
sim1274 runs, 38 downloads
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campus sexual assault community norms
1319.87
#143

Resource Allocation

One of the most challenging tasks in most organizations is the allocation of headcount between time- ... Read more
One of the most challenging tasks in most organizations is the allocation of headcount between time-competing activities. In this model, you will have a chance to explore these sorts of dynamics in the context of a consulting firm, where the same headcount can be allocated to business development activities and client service delivery. You'll see the classic pattern of "Feast or Famine," or the so-called "pig in a snake," emerge.
sim1205 runs, 283 downloads
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human resources headcount
1318.06
#144

SellPhone solo

The Sim is part of the book "Growth Dynamics in New Markets" (https://onlinelibrary.wiley.com/doi/bo ... Read more
The Sim is part of the book "Growth Dynamics in New Markets" (https://onlinelibrary.wiley.com/doi/book/10.1002/9781119118305). This version is for playing alone, RivTel is played by the model (v3.3)
sim1060 runs
SellPhone Growth Diffusion Schaffernicht Groesser
1309.7
#145

Bed capacity model

stcs
sim863 runs, 65 downloads
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Bed Capacity Model Whole Systems
1305.59
#146

Dynamic Modelling of Lionfish Invasion in the Caribbean Sea and Atlantic Ocean

The dynamic model shall explain the rapid diffusion of the lionfish - an invasive species - througho ... Read more
The dynamic model shall explain the rapid diffusion of the lionfish - an invasive species - throughout the Caribbean Sea and the Atlantic Ocean. The interface contains two explanatory models - a simple diffusion model and more realistic convection model - as well as a policy game to manage the regional countermeasures of local decision makers.
sim805 runs
lionfish invasion system dynamics caribbean
1288.29
#147

Process with Complete Quality Control Feedback Mechanisms

This model depicts a process with exogenous inflows where the efficacy of the process descreases in ... Read more
This model depicts a process with exogenous inflows where the efficacy of the process descreases in proportion to time spent in the process. It is followed by a quality control mechanism with sensitivities and specificities which also decrease with time spent in the quality process. This bounded process and quality control is then checked against a gold standard which then adjusts as necessary in alignment with larger policy goals and feeds a larger data set. This model represents a realistic vision of what frontline quality control mechanisms should exist in the healthcare delivery system. It can be used as a tool for policy making to determine what acceptable rates of efficacy and outcome can be tolerated as quality based payments grow in popularity.
model449 downloads
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quality quality control quality based payments us healthcare policy rate dependent quality
1274.6
#148

Carbon Budget Simulator

This model determines the number of years in which the global carbon budget will be exhausted. You s ... Read more
This model determines the number of years in which the global carbon budget will be exhausted. You set the carbon budget as a multiple of current carbon dioxide emissions. You choose a rate of economic growth and a rate of reduction in emissions intensity (emissions/GDP). The model puases when the carbon budget is exhausted. The model can be used to determine the exhaustion of national and regional carbon budgets as well following the same steps.
sim1162 runs
Environment Technology Science Economics
1220.41
#149

Building a Model of Church Growth Using System Dynamics

This simulation talks you through the steps involved in building a simple model of church growth and ... Read more
This simulation talks you through the steps involved in building a simple model of church growth and decline. System dynamics terms are explained. The consequences of hypotheses are examined as they are introduced.
sim804 runs, 14 downloads
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church growth word of mouth enthusiasts model construction Hayward
1210.47
#150

Physiologically Based Pharmacokinetic Model

This model shows how to build a PBPK model and how drug concentrations in different tissues can be s ... Read more
This model shows how to build a PBPK model and how drug concentrations in different tissues can be simulated
sim2003 runs
Drug Pharmacokinetic PBPK Physiologically Based Pharmacokinetic Model
1207.19
#151

GEOSC202 diagenesis lab

sim3516 runs, 5 downloads
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Environment Science
1199.46
#152

COVID-19: Vaccinations in the USA

This model explores the vaccination program in the United States and its effort to control the COVID ... Read more
This model explores the vaccination program in the United States and its effort to control the COVID-19 pandemic. It includes vaccine hesitancy, people's behavior in response to perceived risk, and vaccine effectiveness.
sim2901 runs
Biology Science Education COVID-19 Coronavirus
1182.51
#153

Amalgamated Industries

sim4310 runs, 224 downloads
Download Model
1168.44
#154

COVID-19 Economy

This models the economic impacts of an extended shutdown due to the coronavirus pandemic and explore ... Read more
This models the economic impacts of an extended shutdown due to the coronavirus pandemic and explore the policies adopted by the United States to mitigate these effects.
model1106 downloads
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Business Science Economics COVID-19 coronavirus
1166.52
#155

Educational Outcomes

Educational outcomes in relation to resource allocation
model1055 downloads
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Education resources funding student achievement
1141.32
#156

Product Development Simulator

The Bass Model or Bass Diffusion Model was developed by Frank Bass and it consists of a simple diffe ... Read more
The Bass Model or Bass Diffusion Model was developed by Frank Bass and it consists of a simple differential equation that describes the process of how new products get adopted in a population. The model presents a rationale of how current adopters and potential adopters of a new product interact.
sim951 runs
product development game simulator bass diffusion marketing
1141.26
#157

Molecules

Molecules of System Dynamics Structure: Small generic structures useful in building simulation model ... Read more
Molecules of System Dynamics Structure: Small generic structures useful in building simulation models.
model975 downloads
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Molecules models building blocks learning
1136.8
#158

Systems In Focus: Water

A lot is happening behind the scenes to create this picturesque vista. Rainfall on land creates runo ... Read more
A lot is happening behind the scenes to create this picturesque vista. Rainfall on land creates runoff and therefore stream flow. Some of this runoff is absorbed into the soil. Some of that flows beneath the ground to the stream and some returns to the air through evapotranspiration. Another part of it percolates further down through the soil layers to become part of the groundwater, which provides a base level flow for the stream. Using Stella Professional, we are able to draw a map that corresponds closely to the physical world and then simulate that map to see what happens. This both increases our understanding of how this system works and allows us to experiment with different policies that might lead to alternate, more desirable outcomes.
model994 downloads
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Environment Ecology
1114.76
#159

SellPhone solo v2

The Sim is part of the book "Growth Dynamics in New Markets". You are the country manager of the mbi ... Read more
The Sim is part of the book "Growth Dynamics in New Markets". You are the country manager of the mbile phone company NewPhone and try to diffuse mobile telephony in the country Plutonia. Your competitor is RivTel, and they have the same goal. During 123 months, each of the managers can ser the values of five decision variables and try to acheive the highest possible accumulated profits. (https://onlinelibrary.wiley.com/doi/book/10.1002/9781119118305). This version is for playing alone, RivTel is played by the model (v2)
sim3381 runs
SellPhone Growth dynamics Diffusion Martin Schaffernicht Stefan Groesser
1092.79
#160

Cash for Clunkers

On July 24th, 2009 the Car Allowance Rebate System (CARS), commonly known as "Cash for Clunkers," be ... Read more
On July 24th, 2009 the Car Allowance Rebate System (CARS), commonly known as "Cash for Clunkers," began processing rebate claims. The $1 billion appropriated for the system was exhausted just SIX days later. This simulation explores an alternative program that is self-sustaining AND reduces automobile emissions. Using a combination of fees and rebates this program can finance itself (no emergency appropriations from Congress), reduce gasoline consumption (putting cash back in consumer's pockets), AND contribute to cleaner air for us all!
sim821 runs, 50 downloads
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Cash Cars freebates policy iThink
1074.87
#161

Supply Chain Management without Forecasting

Accurate demand forecasting is an essential part of most supply chain management algorithms. Yet, s ... Read more
Accurate demand forecasting is an essential part of most supply chain management algorithms. Yet, supply even in the most diligently managed chains can deviate widely from demand. Additionally, any disturbance in demand will often be amplified in a supply chain creating what is known as bullwhip effect. This simulation uses three parsimonious models to demonstrate that supply can be regulated reliably without forecasting demand. The inspiration for these models comes from PID (Proportional, Integral, Derivative) control in engineering controllers that utilize multiple functions of error (discrepancy between goal and actual condition) to regulate a quantity.
sim739 runs, 188 downloads
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Business operations management
1065.01
#162

Tu Patineta (A) - English Version

This simulator is based on a case called Tu Patineta (A), written by Dr. Roy Zuñiga, full teacher at ... Read more
This simulator is based on a case called Tu Patineta (A), written by Dr. Roy Zuñiga, full teacher at Incae Business School. It is not intended to offer an accurate solution to the case, but to simulate the possible behaviors of the process considering changes in the input variables described in it.
sim1285 runs
Business Education Operations
1054.25
#163

Supply Chain: Logistic Service Gas Station

This model was developed by Ernesto Vega and Ernesto Lagarda in 2017 for a Company AGM in Sonora Mex ... Read more
This model was developed by Ernesto Vega and Ernesto Lagarda in 2017 for a Company AGM in Sonora Mexico
model834 downloads
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supply chain logistic service gas station interface
1031.79
#164

Inventory Workforce Model

Oscillations in an Inventory Workforce model are examined using the Hayward/Boswell Loop Impact Meth ... Read more
Oscillations in an Inventory Workforce model are examined using the Hayward/Boswell Loop Impact Method.
sim523 runs, 155 downloads
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Loop Impact Loop Impact Workforce Inventory Control Oscillations
1024.55
#165

Collins Theory of Geopolitics - Effect of War

The spread of an empire according to the theory of Randall Collins and equations of Peter Turchin
sim400 runs, 51 downloads
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war empire geopolitics collins turchin
1014.13
#166

UHE1

This sim supports exploration of the behaviour shown in Figure 4.3 of the book "Understanding Human ... Read more
This sim supports exploration of the behaviour shown in Figure 4.3 of the book "Understanding Human Ecology" by R. Dyball and B. Newell (2015)
sim3288 runs
system dynamics basic concepts
1005.26
#167

Grit-Affect-Performance

by Raafat
A first attempt at conceptualizing the dynamic relationship between emotions and grit and their infl ... Read more
A first attempt at conceptualizing the dynamic relationship between emotions and grit and their influence on student performance in cyberlearning environments
model700 downloads
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learning support scaffold online science
997.167
#168

Leg VS Asprin

ur leg, vs, some asprin
model845 downloads
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leg asprin fight title fight fight for title
992.618
#169

Wetland Forestland hydrology

Simulates multiple hydrological processes through a forestland and wetland on the Western Boreal Pla ... Read more
Simulates multiple hydrological processes through a forestland and wetland on the Western Boreal Plain, Canada
model916 downloads
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Precipitation Evaporation Infiltration Groundwater
985.353
#170

Prediction-Wave3-Part1

sim4157 runs
Health
984.24
#171

Model 20. DDI Drug-Drug Interactions - Pharmacodynamic

This model demonstrates the interaction between two agonists and allows the efficacy (Emax) of one t ... Read more
This model demonstrates the interaction between two agonists and allows the efficacy (Emax) of one to be varied
model964 downloads
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Drug Interactions Pharmacodynamic Partial Agonist
983.727
#172

Fun with Springs-LevelA

This simulation is part of the oscillations series from the Creative Learning Exchange, http://www.c ... Read more
This simulation is part of the oscillations series from the Creative Learning Exchange, http://www.clexchange.org/curriculum/complexsystems/oscillation/default.asp
sim1439 runs, 8 downloads
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spring physics oscillation
981.589
#173

Evolution: Grants Finches

Models the effects on population sizes of ground finches with different beak sizes in response to di ... Read more
Models the effects on population sizes of ground finches with different beak sizes in response to different amounts of annual precipitation.
sim8993 runs
evolution biology natural selection
976.6
#174

The Wolves of Yellowstone

Keystone species are defined as a plant or animal that plays a unique role in the way the ecosystem ... Read more
Keystone species are defined as a plant or animal that plays a unique role in the way the ecosystem functions. But what would happen if that species were removed? What ripple effects would be caused by the absence of this species? We can examine these questions by looking at the wolf population in Yellowstone National Park. Wolves once flourished in Yellowstone and its surrounding areas. However, soon after the area was settled, misperceptions caused by fear and hatred fueled a large extermination effort of the wolves. For nearly 70 years, wolves were absent from Yellowstone. During this time, the ecosystem changed and diminished until scientists realized the value of the wolves and reintroduced them to Yellowstone. This model, built in iThink, uses storytelling to understand the dynamics of this keystone species. What animals were affected by their presence or absence. See how wolves play a part in not only population control of their prey but other animals and even plants far down the trophic levels.
sim30 runs, 411 downloads
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Keystone species Wolves wolf Trees Aspen
966.444
#175

mse-litsim

Modelo de Simulación de Escenarios MSE-LITSIM
sim894 runs
gestión áreas litorales eutrofización estuarios humedales
957.55
#176

2019 Step3 renew

sim19277 runs
951.48
#177

The Shrimp Lab

“The Shrimp Commodity System Learning Lab” was designed for individuals seeking to build their syste ... Read more
“The Shrimp Commodity System Learning Lab” was designed for individuals seeking to build their systems thinking muscle and policy-design skills. It has been used successfully in undergraduate and graduate courses where business sustainability and/or system dynamics applications are emphasized. The format offers learners a progression of interactive experiences on which to build an understanding of the issues of the global shrimp industry system, including wild fisheries and aquaculture, its financial instability, the environmental issues it faces, and how individual policy alternatives can be tested, analyzed and combined to address industry performance. The Learning Lab has two learning pathways: The Systems Thinking Basics course shows the application of systems thinking and stock-flow mapping as tools to hypothesize and express underlying system feedback structures contributing to issues such as resource depletion and environmental pollution. The Policy and Scenarios Advanced course deepens understanding of systems behavioral patterns by presenting policies which address commodity systems behavior challenges and by using alternative scenarios dealing with market forces as tests. Students in a course could be asked to provide their recommendations for a policy set which best achieves multiple performance objectives: industry wide profit growth for the two industry sectors, achieve coastal effluents improvements, and avoid large oscillations of shrimp populations and resource depletion in the wild fishery. Additional information is available in the Technical Note (UVA-OM-1428) that offers information for individual preparation assignments, suggestions for Group workshop activities, helpful causality notes for instructors, and insights into policy analyses. To obtain this Note or request further information about related shrimp industry cases, (UVA OM 1388 and 1389), contact Darden Business Publishing at http://store.darden.virginia.edu/contactus The Learning Lab was developed by Chris Soderquist, Pontifex Consulting and Professor Robert D. Landel of the Darden School, University of Virginia and is based on original research from Donella Meadows Institute (formerly Sustainability Institute) and Pontifex Consulting. Copyright © 2009 by the University of Virginia Darden School Foundation, Charlottesville, VA.
sim3418 runs
Environment Biology Business Economics Ecology
945.781
#178

Gora Model Balanced Scorecard

sim4028 runs
945.24
#179

Supply and demand model

Supply and demand model
sim921 runs, 231 downloads
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Supply demand model money stella
944.114
#180

Customer-Employee Satisfaction

Research shows a strong correlation between employee satisfaction and customer satisfaction. Underst ... Read more
Research shows a strong correlation between employee satisfaction and customer satisfaction. Understand the correlation through this model, which illustrates the causal relationship between the two.
sim447 runs, 269 downloads
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Customer satisfaction employee satisfaction human resourses
942.908
#181

YVSP Neighborhood

A neighborhood scale version of the Youth Violence System Project Model
sim4167 runs
916.29
#182

Stella project

Simulation showing how cyber attacks have grown in various years.
model790 downloads
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amount of attacks attacks per year increase rate of attacks
902
#183

Magallanes ESP

En este simulador, Usted juega el papel del director de una planta de producción de la emtresa magal ... Read more
En este simulador, Usted juega el papel del director de una planta de producción de la emtresa magallanes. Debe manejar el personal de venta y la capacidad de producción de modo a obtener un crecimiento fuerte y sostenido de las ventas.
sim546 runs
Magallanes Sobrecrecimiento y colapso Martin Schaffernicht Universidad de Talca
883.049
#184

Systems In Focus: Energy

Building capacity in alternative energy sectors takes time and large investments. The transition to ... Read more
Building capacity in alternative energy sectors takes time and large investments. The transition to other sources has to be financially feasible, as well as timely to prevent further damage from pollution. How can the mix of electricity generation technology change, based on both cost and pollution? This Systems in Focus model analyses how capacity can be developed in different energy sectors over time.
model984 downloads
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Technology Science Energy
882.144
#185

Service Call Center Dynamics

One organization in the service delivery business experienced a situation where the number of delive ... Read more
One organization in the service delivery business experienced a situation where the number of delivery requests increased dramatically due to a seasonal promotion. This increase in requests caused an overload on the service delivery staff by not only having more people requesting service, but also because the amount of time spent with each customer increased. This model is designed to describe why this occurred in a way that can be transferable to other service delivery organizations.
sim435 runs, 222 downloads
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discrete modeling queues conveyors cycle time
868.567
#186
The Stella version of Arctic Mediterranean Double Estuarine Cirulation Box Model
sim1161 runs, 7 downloads
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ocean circulation freshwater
867.52
#187

Multiple Retailer Supply Chain

Experience the dynamics of overshooting/undershooting inventory typical in the retail industry. Tour ... Read more
Experience the dynamics of overshooting/undershooting inventory typical in the retail industry. Tour this supply chain model to understand the structure from the factory through multiple retailers to the consumer.
sim278 runs, 306 downloads
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iThink inventory arrays conveyors supply chain
850.095
#188

Aquatic Trophic Productivity Model

The ATP model is a dynamic food web simulation model.
sim1616 runs
food webs river restoration fish biomass
822.873
#189

Evolving Bits N=40

sim2243 runs
evolution bits receptor substrate
820.76
#190

Diagrama causal innovacion

by Randiel
diagrama para representar el ciclo de innovacion
diagram892 downloads
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innovacion empresa ciclo smart planeamiento
814.176
#191

Population

Sample population model with graph
model1155 downloads
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beginner sample population model
799.02
#192

Model 17. DDI 5 Inhibition of Gut and Hepatic Metabolism

This model demonstrates the effect of an inhibiotr that acts on enzymes both the gastrointestinal me ... Read more
This model demonstrates the effect of an inhibiotr that acts on enzymes both the gastrointestinal membrane and the liver. It also demonstrates the effect of grapefruit juice on drugs netaboliized by CYP3A
sim573 runs
Intestinal extraction Fg DDI Drug interactions Grapefruit juice
794.397
#193

General Practice Advanced skill simulator

A model to explore changing roles within the advanced skilled workforce for General Practice in the ... Read more
A model to explore changing roles within the advanced skilled workforce for General Practice in the UK.
sim389 runs
Primary care workforce skills level strategic workforce planning Whole
791.562
#194

Soluzioni che si vendicano

Applicazione dell'archetipo FIxes That Fail al caso della manutenzione software presso clienti
sim893 runs, 2 downloads
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Fixes That Fail Archetype Software Business
773.37
#195

MNH Strategic Model

Strategic model of country-level policies to reduce maternal and neonatal mortality.
sim809 runs
global health maternal survival neonatal survival
761.988
#196

Systems In Focus: Conservation

Fishing areas are within the commons, which encourages greater investment in ships when there is dem ... Read more
Fishing areas are within the commons, which encourages greater investment in ships when there is demand. More importantly, we can never really know the population of the given fishery and therefore whether it is in danger of being fished out. This model explores the trade-offs between investing in more ships to catch more fish and the long-term viability of the fishery.
model669 downloads
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Environment Business Technology Ecology
757.458
#197

Dairy value chain development in Nicaragua

Dairy farmers in Matiguás, Nicaragua face feed system constraints that reduce their competitiveness. ... Read more
Dairy farmers in Matiguás, Nicaragua face feed system constraints that reduce their competitiveness. Conventional value chain analysis methods are unsuited to prioritize upgrading options. System dynamics modeling of the Matiguás dairy value chain was therefore used to quantify and analyse policy impacts. The model was constructed and tested with stakeholders in the Matiguás dairy value chain through group model building.
sim333 runs, 1 download
Dairy value chain Nicaragua interventions policy
750.937
#198

Dodds Stella Modeling

a SICK model, YEET!
model808 downloads
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Swag Stella Artois Model Scott
731.182
#199

Fish Banks, Ltd.Game

by Saeed
In the Fish Banks, Ltd. game (originally developed as a board game by Professor Dennis L. Meadows in ... Read more
In the Fish Banks, Ltd. game (originally developed as a board game by Professor Dennis L. Meadows in 1986), teams of players manage their own fishing companies. At the beginning of the game, each fishing company has equal financial resources and fishing fleet. Each company has the same operating costs and technology. At the beginning of every simulated year, the companies make decisions about building, buying, and/or selling ships, whether to fish or not, and how far to send their fleet for fishing. The game's objective is to maximize total assets at the end of the simulation. The game developed here is a modified version of the Meadows' game as explained in the game rules.
sim307 runs
Environment Economics Ecology Education Dennis Meadows
728.34
#200

Bricks to Clicks

Experience the dynamics of making a business shift from traditional to e-commerce. Simulate differen ... Read more
Experience the dynamics of making a business shift from traditional to e-commerce. Simulate different scenarios for how you’ll allocate spending on marketing versus infrastructure. You will see one of the more common dynamics in making a business shift, what Systems Thinkers refer to as the "worse before better" dynamic. If initial investments are made in the infrastructure quality rather than in marketing, total customers will actually fall for awhile. But if increasing amounts are spent on marketing (once the infrastructure is in place) then total customers will begin to explode. And the transition becomes successful!
sim520 runs, 146 downloads
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retail strategy iThink
722.773
X

Sim App (Sim)

An interface that allows users to interact with a model.

Image of a sim

Sim apps allow users to interact with a model using buttons, sliders, knobs, tables, graphs, and storytelling. These interactions help users understand how parts of a system interact.

Interfaces are created by model authors in the Stella desktop software and can be uploaded to the isee Exchange™.

Model

A diagram that represents how elements in a system influence one another.

Image of a model

Models are mathematical representations of how elements in a system are connected and interact (e.g., ecosystems, organizations, supply chains). When running models on the isee Exchange™, results can be viewed in output devices like graphs and tables.

Models appear in the isee Exchange™ directory when authors upload them from the Stella® desktop software or create them with Stella Online™.

Causal Loop Diagram (CLD)

A map that represents the feedback structure of a system.

Image of a CLD

CLDs are high-level maps that represents the feedback structure of a system and easily communicate the essence of a model. They appear in the isee Exchange™ when authors upload them from the Stella desktop software or create them with Stella Online™.