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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We found 40 items
Include in results:
#1

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.
sim270,612 runs
Biology Science Ecology Education
211153.06
#2

Catastrophic Regime Change in Aquatic Ecosystems

sim145,294 runs
Ecology
30083.44
#3

Carbon Cycle Simulation

Simulation tracks the movement of carbon to and from the atmosphere in Gt C (and Gt CO2). Users can ... Read more
Simulation tracks the movement of carbon to and from the atmosphere in Gt C (and Gt CO2). Users can manipulate with graphical inputs the changes in fossil fuel emissions, land-use, and ocean sinks.
sim12,756 runs
Environment Biology Science Ecology Education
11845.566
#4

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).
sim17,843 runs, 89 downloads
Download Model
population ecology
7712.2593
#5

Greenhouse Gas Emissions Management Tool

sim2,316 runs
Environment Business Technology Science Economics
6402.75
#6

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.
model3,618 downloads
Download Model
Environment Ecology Systems in Focus Renewable Resources Raw Material
6030.202
#7

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.
model3,799 downloads
Download Model
Environment Ecology Systems in Focus
5334.6704
#8

Covid19-Epidemie-ModelEducationBase1B

This model was copied from Gigaroff: 1. French (in English in 2.) Modèles pour mieux comprendre la ... Read more
This model was copied from Gigaroff: 1. French (in English in 2.) Modèles pour mieux comprendre la dynamique d'une épidémie et comment les mesures prises permettent d'en atténuer les effets" - Projet interdisciplines Hervé Gigaroff, Lycée "Emile Combes" de Pons 17 (France)-
 • Ceci est le Modèle de base “1.B” pour commencer à mieux comprendre la dynamique d'une épidémie, type CoVid 19, , simplifiée mais tout à fait réaliste… …Avant de voir, avec des modèles suivants, comment les mesures prises permettent d'en atténuer les effets" Pour les “matheux”, fans d’équations différentielles, ce modèle n’est jamais que la mis en forme, selon les lois de le “SYSTÉMIQUE DYNAMIQUE” de ce qui est représenté , en équations différentielles dans cette excellente vidéo: https://www.youtube.com/watch?v=-2tI3MQFqkI&fbclid=IwAR3QdfrTCQPKNUogozNchAlpu0SwTlvQx_fPNaTDjZ1ijdk6wc0snzJc69k Donc ce modèle permet aux “non-matheux” d’aborder cette compréhension… 2 jeux “Épidémie Covid19 #1 et #2” , permettant de vivre (en”pour de semblant”) la dynamique d’une épidémie, vont accompagner ces modèles , qui ne sont que le débriefing de ce qui s’est passé dans ces “jeux”. • Websites récents sur "Epidémies & modélisation" : 1.https://www.youtube.com/watch?v=bM7AOBxqjnE, titré "Cette pandémie, vue depuis 2021" du site "Dirty Biology", 2.https://sciencetonnante.wordpress.com/2020/03/12/epidemie-nuage-radioactif-et-distanciation-sociale/ , titré "Épidémie, nuage radioactif et distanciation sociale", 3.https://medium.com/tomas-pueyo/coronavirus-le-marteau-et-la-danse-bce68d354c0c, titré "Coronavirus, le marteau et la danse". -------------------------------------------------------------------------------------------------------------------- • 2. English: Models for a better understanding of the dynamics of an epidemic and how protective measures make it possible to mitigate the effects "- Interdisciplinary project Hervé Gigaroff, High-school Emile Combes de Pons 17 (France) • Here is Basic model “1.B” to begin to better understand the dynamics of an epidemic, type CoVid 19, in asimplified but completely realistic way… … Before seeing, with the further models, how measures taken can mitigate the effects For the "math minded students”, fans of differential equations, this model is nothing else than the shaping, according to the laws of the "DYNAMIC SYSTEM" of what is represented, in differential equations in this excellent video : https://www.youtube.com/watch?v=-2tI3MQFqkI&fbclid=IwAR3QdfrTCQPKNUogozNchAlpu0SwTlvQx_fPNaTDjZ1ijdk6wc0snzJc69k So this model allows the "non-math minded students" to approach this understanding ... 2 games “Covid19 epidemic # 1 and # 2”, allowing to live (“for pretense”) the dynamics of an epidemic, will accompany these models, which are only the debriefing of what happened in these “games”. • Websites récents sur "Epidémies & modélisation" : 1.https://www.youtube.com/watch?v=bM7AOBxqjnE, titled "This pandemia, seen from 2021" from website "Dirty Biology", 2.https://sciencetonnante.wordpress.com/2020/03/12/epidemie-nuage-radioactif-et-distanciation-sociale/ , titled "Epidemic, nuage radioactive cloud and social distanciation", 3.https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56 , titled "Coronavirus, the hammer and the dance".
model1,007 downloads
Download Model
Environment Biology Science Ecology Education
4410.716
#9

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.
model3,120 downloads
Download Model
Environment Business Technology Ecology Systems in Focus
4350.44
#10

Exponential Growth

sim16,602 runs
Biology Ecology
4241.42
#11

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

sim3,877 runs
Environment Biology Business Technology Science
2508.72
#12

Predator Prey Dynamics

This simple model illustrates the basic relationships that govern the dynamics of a predator-prey sy ... Read more
This simple model illustrates the basic relationships that govern the dynamics of a predator-prey system.
sim2,586 runs
Environment Biology Science Ecology
1935.7053
#13

M330C6.2.4 Resource tax

sim3,633 runs
Biology Economics Ecology Education
1906.05
#14

감염모델 (SIR Model) 2.0

기존 감염모델 연장선에서 작성했습니다. 따라서, 기존 모델과 설명이 이어집니다. 기존 모델을 확인하시기 바랍니다.
sim2,427 runs
Environment Biology Ecology Education
1872.215
#15

Power Devolution in Community-Based Natural Resource Management

© Christina Gkini, Ashish Shrestha & Birgit Kopainsky 2020 A model examining the devolution of power ... Read more
© Christina Gkini, Ashish Shrestha & Birgit Kopainsky 2020 A model examining the devolution of power in community-based Natural Resource Management programmes, originally developed for the course GEO-SD325 at UiB and presented at the International System Dynamics Conference 2020.
model1,079 downloads
Download Model
Business Ecology resource management public policy UiB
1839.5266
#16

Interfaces in Stella Architect

Example interface features in Stella Architect in a mouse population simulation
sim1,580 runs
Biology Ecology Interface; Capacity Contraint; Population
1676.79
#17

Análisis sistémico del proceso de diagnóstico del dengue

Permite analizar el proceso de transmisión, diagnostico y control del dengue tomando como caso base ... Read more
Permite analizar el proceso de transmisión, diagnostico y control del dengue tomando como caso base un hospital de primer nivel de México.
sim2,711 runs
Environment Biology Ecology
1589.6803
#18

Exploring Complex Systems with Canada Lynx and Snowshoe Hare

Prey and predators appear to follow population trends based on one another; this trend is known as t ... Read more
Prey and predators appear to follow population trends based on one another; this trend is known as the predator-prey cycle. Through the model the cycle will be analyzed in relation to snowshoe hare and Canada lynx populations from the mid-1800s to the mid-1900s in North America.
model929 downloads
Download Model
Environment Biology Science Ecology Education
1387.2433
#19

Anooja EVS Assignment- species richness model

Species richness on island measured considering extra external factors. Based on island biogeographi ... Read more
Species richness on island measured considering extra external factors. Based on island biogeographic theory and species richness curve.
model367 downloads
Download Model
Environment Biology Technology Science Ecology
1230.3153
#20

tragedy of commons water crisis

Water scarcity is the lack of fresh water resources to meet water demand.
model799 downloads
Download Model
Environment Biology Business Technology Science
1208.567
#21

Fish Banks, Ltd.Game

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.
sim353 runs
Environment Economics Ecology Education Dennis Meadows
1118.8804
#22

ccf poverty popuplation and climate change

a cld covering various sectors and majorly interacting between social and ecological systems.
diagram675 downloads
Download Model
Environment Biology Business Technology Science
1009.115
#23

Positive Feedback

Basic positive feedback model
model669 downloads
Download Model
Environment Biology Business Technology Science
984.141
#24

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.
sim6,469 runs
Environment Biology Business Economics Ecology
945.7813
#25

plugrisost

RWH system
model546 downloads
Download Model
Environment Technology Economics Ecology Education
895.92
#26

Garden hydrology-model

This model simulates soil moisture, leachate, and evapotranspiration in an urban garden as a functio ... Read more
This model simulates soil moisture, leachate, and evapotranspiration in an urban garden as a function of rainfall and irrigation inputs, and soil organic matter. It was developed based on empirical data from a 5-year study at the University of St. Thomas in Saint Paul, Minnesota.
sim1,444 runs
Environment Science Ecology
832.5203
#27

Lynx_Hare2

This model was copied from Lindsay Gutting: Prey and predators appear to follow population trends b ... Read more
This model was copied from Lindsay Gutting: Prey and predators appear to follow population trends based on one another; this trend is known as the predator-prey cycle. Through the model the cycle will be analyzed in relation to snowshoe hare and Canada lynx populations from the mid-1800s to the mid-1900s in North America.
model513 downloads
Download Model
Environment Biology Science Ecology Education
806.605
#28

Beef Consumption Reduction and Environmental Impacts Mitigation

This model helps users understand how reducing beef consumption reduces GHG, water and land use.
sim1,357 runs
Environment Science Ecology
794.1257
#29

Two Variations - Population Growth

model1,263 downloads
Download Model
Biology Science Ecology Education
785.43
#30

Negative Feedback

Basic negative feedback model
model530 downloads
Download Model
Environment Biology Business Technology Science
784.12
#31

trag of commons

diagram554 downloads
Download Model
Environment Biology Business Technology Science
772.94
#32

Limiting Nutrients Model

model1,347 downloads
Download Model
Environment Ecology Education
769.32
#33

Electric vehicles sales in Norway

This model was copied from MINDSproject: Daria Yermolova and Valentina Orliuk examine the various e ... Read more
This model was copied from MINDSproject: Daria Yermolova and Valentina Orliuk examine the various effectors on the electric car market in Norway as part of a joint project for SD304 at UIB.
model509 downloads
Download Model
Environment Business Technology Science Economics
767.55
#34

WaterScarcityDemo

by mettkyl
A simple model to explore water draw down and the effects of Jevon's Paradox and the Treadmill of pr ... Read more
A simple model to explore water draw down and the effects of Jevon's Paradox and the Treadmill of production
sim1,259 runs
Environment Science Ecology
750.452
#35

Huerto de un metro cuadrado

Se compone de plantas pequeñas, grandes y verticales. Es ideal para espacios pequeños. se divide en ... Read more
Se compone de plantas pequeñas, grandes y verticales. Es ideal para espacios pequeños. se divide en cuadrados pequeños; cada espacio tiene una legumbre, flor o hierba diferente. En la construcción de la estructura se utilizan tubos de pvc (en la maqueta se utilizaron pajillas). Las plantas más grandes van en la fila de atrás, las más chicas en las filas posteriores, más cercanas a la dirección donde les llegue la luz del sol. Las plantas verticales como los tomates se cuelgan de los tubos. Hay que sujetar el marco vertical con alambre para dar seguridad contra los vientos fuertes. 1. Este sistema permite cultivar en pequeños espacios. 2. El espacio permite alcanzar toda la huerta para sembrar, regar y cosechar, sin necesidad de caminar encima de él (para no compactar el suelo). 3. La rotación de los cultivos es automática. Un cultivo de estación larga como el tomate, puede ser plantado entre otros cultivos de cosecha rápida y serán cosechadas antes que la planta necesite espacio. 4. Ya que es posible alcanzar la huerta al nivel de la cintura, éste formato, facilita el cultivo para discapacitados físicos.
model374 downloads
Download Model
Environment Technology Science Ecology
736.2633
#36

Räuber Beziehung

by gringe
harry is gringe und er liebt hermine doch! Harry Styles wurde am 1 februar 26!!!!! Ich liebe Pomme ... Read more
harry is gringe und er liebt hermine doch! Harry Styles wurde am 1 februar 26!!!!! Ich liebe Pommes mit Mayo und Gurken Nano wurde von aliens geschickt
model391 downloads
Download Model
Environment Biology Business Technology Science
731.78033
#37

M330C6.2.5 ITQ policy

sim1,674 runs
Economics Ecology Education
646.76
#38
Test
model434 downloads
Download Model
Environment Biology Business Technology Science
633.876
#39

COVID-19 Baseline Model Feedback Analysis

sim927 runs
Environment Biology Science Ecology Education
585.34
#40

감염모델 (SIR Model)

'감염'이라는 주제는 시스템다이내믹스 교과서에서 다루는 대표 모델 중 하나입니다. 감염 구조를 이해하고 정책에 따른 변화를 시뮬레이션해 보시기 바랍니다.
sim955 runs
Environment Science Ecology
582.1433
X

Uploading a Bundle from Zip

Instead of creating bundles, categories, and assemblies one by one, you can upload a single zip file that contains all of your bundle's content. To create your zipped bundle, make a folder with your bundle's name and add subfolders with your categories' names. The folder tree should have the same structure that you want the categories to have in your bundle. Place your assembly .stmx files in the appropriate category folders, then zip your bundle folder and upload it using the Upload Bundle from Zip link above.

Assemblies, Bundles, and Categories

Assemblies are self contained models that demonstrate common ways to connect together building blocks and that can be used as parts of other models. This is analogous to using prefabricated wall and roof pieces to construct a house.

Bundles are groups of assemblies with a common use or theme. For example, a Health Care bundle might contain a variety of assemblies that aid in creating health care models. When you download assemblies from the isee Exchange™, you download an entire bundle, rather than individual assemblies.

Categories are subgroups of assemblies within a bundle. For example, a Health Care bundle might contain a Funding category for assemblies related to the management of hospital funds. All assemblies must be assigned to a category—they cannot be assigned to the root of a bundle.

Assemblies, bundles, and categories can be created and uploaded to the isee Exchange™ via the options on the Manage My Assemblies page. To learn more, visit our help pages, or take our assemblies tutorial.

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™.