John Hayward's Profile
Number of items: 14
Date joined: Aug 24 2016
I am a Visiting Research Fellow in Mathematics at the University of South Wales. Before my retiremen ...Read more 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 religions, political movements and civilisations. In the mid-1990s, I moved into system dynamics to help present models to non-technical audiences and improve model construction. Since then, I have used my background in physics to help understand the relationship between SD model structure and behaviour, developing the loop impact method and the Newtonian interpretative framework. I am currently a vice president of the UK chapter of the SD society, with responsibility for membership.
John Hayward's Work
#1
Overshoot and Collapse
Overshoot and collapse behaviour is examined using the Hayward/Boswell Loop Impact Method.
#2
The Dynastic Cycle
The model of Feichtinger, Forst and Piccardi.
#3
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.
sim
⋮ 3548 runs,
144 downloads
Download Model
Download Model
Loop Dominance
Limits to Growth
Shifting loop dominance
Urban Dyanmics
Loop Impact
#4
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.
sim
⋮ 1057 runs,
179 downloads
Download Model
Download Model
Loop Impact
Loop Impact
Workforce
Inventory Control
Oscillations
#5
Collins Theory of Geopolitics - Effect of War
The spread of an empire according to the theory of Randall Collins and equations of Peter Turchin
#6
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.
#7
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.
sim
⋮ 1854 runs,
32 downloads
Download Model
Download Model
church growth
word of mouth
enthusiasts
model construction
Hayward
#8
Rise and Fall of Empires
Empires rise through the desire for things such as power, peace & wealth. It can even attract others
... Read more
Empires rise through the desire for things such as power, peace & wealth. It can even attract others. However the rise of nationalism, institutionalism and the remoteness of the ruling elite can lead to imperial decline
sim
⋮ 34 runs
Empire
Overshoot and decline
Imperial Expansion
Power
Peace
#9
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.
sim
⋮ 2280 runs,
228 downloads
Download Model
Download Model
Business
Loop Dominance
Limits to Growth
Shifting loop dominance
Urban Dyanmics
#10
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.
sim
⋮ 1604 runs,
60 downloads
Download Model
Download Model
Church growth
Revival
Religion
Epidemiology
Enthusiasts
#11
Gone with the Wind
The loop impact method of Hayward/Boswell is applied to a single second order balancing loop using t
... Read more
The loop impact method of Hayward/Boswell is applied to a single second order balancing loop using the narrative of the love relationship between Rhett and Scarlet from Gone with the Wind.
sim
⋮ 205 runs,
21 downloads
Download Model
Download Model
Loop dominance
Loop impact
Oscillation
Second order loop
Hayward
#12
Spread of Disease
A simple SIR model is examined using the Hayward/Boswell Loop Impact Method.
#13
Collins Theory of Geopolitics - Logistical Load
The spread of an empire according to the theory of Randall Collins and equations of Peter Turchin. I
... Read more
The spread of an empire according to the theory of Randall Collins and equations of Peter Turchin. Includes limits to growth due the distance beween the empire's expansion zone and centre.
#14
Demographic Fiscal Model of State
An agrarian population can exceed its normal carrying capacity by the formation of a state that help
... Read more
An agrarian population can exceed its normal carrying capacity by the formation of a state that helps improve land productivity. As the population and state grow, it becomes harder for state revenue to stay ahead of expenditure. Eventually the state runs out of money and collapses, with a large drop in population numbers.
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.
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.
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.
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™.