profile image
Number of items: 11
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. Hide full description


John Hayward's Work

#1

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.
sim87 runs, 3 downloads
Download Model
Church growth Revival Religion Epidemiology Enthusiasts
#2

Spread of Disease

A simple SIR model is examined using the Hayward/Boswell Loop Impact Method.
sim12 runs
Download Model
SIR Disease Infection Loop dominance loop impact
#3

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.
sim418 runs, 4 downloads
Download Model
Loop dominance Limits to Growth archetype loop impact
#4

Overshoot and Collapse

Overshoot and collapse behaviour is examined using the Hayward/Boswell Loop Impact Method.
sim3 runs
Download Model
Overshoot collapse loop impact loop dominance
#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
sim96 runs, 5 downloads
Download Model
war empire geopolitics collins turchin
#6

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.
sim26 runs, 5 downloads
Download Model
limits to growth war empire geopolitics Collins
#7

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.
sim25 runs
Download Model
Loop Dominance Limits to Growth Shifting loop dominance Urban Dyanmics Loop Impact
#8

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.
sim158 runs, 5 downloads
Download Model
Loop Impact Loop Impact Workforce Inventory Control Oscillations
#9

The Dynastic Cycle

The model of Feichtinger, Forst and Piccardi.
sim100 runs, 5 downloads
Download Model
History limit cycles social modeling psychology
#10

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.
sim47 runs, 2 downloads
Download Model
Turchin Empire Collapse Collins Geopolitical
#11

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
sim2 runs
Empire Overshoot and decline Imperial Expansion Power Peace
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™.