Difference between revisions of "Understand IFs"
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=Structure-Based and Agent-Class Driven Modeling=
=Structure-Based and Agent-Class Driven Modeling=
= Dominant Relations =
Revision as of 15:18, 26 June 2017
Help During Use of IFs
The full Help System is always available to users of IFs from the Help option on the Main Menu. In addition, however, there are several types of Help that are available at key points of model use and that are generally more specific to the specific points of model use. The goals of the IFs system are user-friendliness with respect to the interface and transparency and openness with respect to the structure of the model.
Context Sensitive Help. The use of the F1 key will normally provide screens that provide information about the specific form or window being used at the time. These explain the interactive interface of the model.
Pop-up Menus with Help Options. Users also want Help, however, when dealing with variables and parameters in the model. They want to know longer names for the short ones sometimes used in the model and want to understand the causal linkages of variables to each other. The use of pop-up menus at many places when variables/parameters are being chosen or used for inputs and for display opens up a variety of options for understanding the names and linkages. For instance, when a table is displayed, a double-click on the body of the table with the right or left mouse button produces a pop-up menu with several options. Similarly, at the bottom of the Display Menu or the Variable Selection form are status boxes with short variable names selected by the user. A right or left mouse click brings up a similar pop-up menu.
The pop-up menu system was developed by Mohammod T. Irfan.
Understanding the Modeling Approach
There are many "routes to understanding" of a model: the general philosophy of the modeling approach, the key or dominant relationships and dynamics in the model, the primary causal linkages in the model (using flow charts or causal diagrams), the equations, the full model computer code, and the data used. In order to facilitate the search for understanding, this documentation provides each of these paths, more or less in the sequence of this listing.
The documentation groups most of the "routes to understanding" under issue modules (such as the energy module). The exception is model code, which is collected across modules because of its specialized character.
The IFs model is constantly evolving. In addition to the documentation here, there is stand-alone documentation on the Reports page of the IFs project web site. The model user would be advised, in particular, to look at the paper on "The Structure of International Futures (IFs)." <header><hgroup>
IFs Structure: Elements and Philosophy
A basic mental model helps frame the approach to modeling in International Futures:
Global human systems consist of classes of agents and larger structures within which those agents interact. Over time agents and the larger structures evolve in processes of mutual influence and determination.
That conceptualization shapes the methodological approach:
At one time global models were categorized as using either econometric or systems dynamics methodologies. IFs draws upon techniques found in both traditions, but reaches beyond them, especially in its structural representations.
Structural representations include cohort-component systems for population; markets for production, exchange, and consumption of goods and service; and social accounting matrices for financial flows.
This emergent IFs methodology is Structure-Based and Agent-Class Driven Modeling.
More detail is available on the manifestation of this modeling approach for the following structural systems of IFs:
- Structure and Agent System: Agriculture
- Structure and Agent System: Demographic
- Structure and Agent System: Economics
- Structure and Agent System: Education
- Structure and Agent System: Energy
- Structure and Agent System: Environment
- Structure and Agent System: Governance
- Structure and Agent System: Health
- Structure and Agent System: Infrastructure
- Structure and Agent System: Interstate Interaction
- Structure and Agent System: Socio-Political
Structure-Based and Agent-Class Driven Modeling
Any computer simulation or other model will have some relationships and dynamics that dominate the behavior of the model and that therefore most heavily influence the analyses done with the model. Understanding these dominant relations will facilitate model use, particularly in the definition of key or framing scenarios.
The value added by more detailed specification of relationships in the model will lie partly in more probing analysis, often around specific policy options. Much of the value added by a more complete model specification will, however, lie in the dynamics of the full model.
For an introductory summary of dominant relations and dynamics by submodule:
- Dominant Relations: Agriculture
- Dominant Relations: Demography/Population
- Dominant Relations: Economics
- Dominant Relations: Education
- Dominant Relations: Energy
- Dominant Relations: Environment
- Dominant Relations: Governance
- Dominant Relations: Health
- Dominant Relations: Infrastructure
- Dominant Relations: Interstate Politics
- Dominant Relations: Socio-Political