Identifies options available and key choices. Analysis of complex decisions with significant uncertainty can be confusing because: the consequence that will result from selecting any specified decision alternative cannot be predicted with certainty. there are often large number of different factors that must be taken into account may be useful Continue Reading
02 – Understanding Systems
Module
Cause and Effect Diagram
Cause and Effect diagrams sometimes called fishbone diagrams or Ishikawa (name of the developer). Models casual relationships that occur. Identifies what is causing what effect. Will identify multiple causes if they exist – critical for understanding complex situation. Will also identify feedback loops. Diagram focuses on causes rather than effect. Continue Reading
Further Model Types and their uses
Rich Pictures Often first stage in design process Free format diagram to capture system Identifies politics, processes, emotions Theme places in middle, link words placed around it Systems Dynamics Show states and rates for given situation Example: human population and rate of increase/decrease Other states can be modelled against human Continue Reading
A brief summary of Model Considerations
Number of elements to consider when building models: Define model purpose when designing model. Model should be verified and validated. Designed by humans from specific perspective, may be flawed. Model only gives partial view of situation/system. Number of models required to gain full understanding of situation/system providing different views. Abstraction Continue Reading
Other Classification Systems
In addition to static and dynamic, models can also be defined as quantitative and qualitative. Quantitative models similar to numeric models quantify situation with facts and data Qualitative models shows structure of elements/components Other model classifications are hard and soft models. Hard models are like quantitative models and are based on Continue Reading
Static or Dynamic Models
Models classified as either static or dynamic models. Static models tend not to change much, only if significant change in situation London tube map changes only when new line added powerful source of information/understanding if situation is constant Used in business environment to understand enterprise/system, simulation used to analyse behaviour Continue Reading
Word, Visual and Mathematical Models
Word Models: Consist of words. Examples: a specification, an abstract Provide significant amount of information Can be structured in different ways Weakness: linear and not multi-dimensional – hard to provide complex relationships, can become unwieldy Visual Models: Type of picture – ‘a picture paints a thousand words’ Show a lot Continue Reading
Types of Models
Covered in previous lesson – classification of models rather than specific types. Continue categorising and classifying models. Role and use of several types of models with emphasis on Dynamic and Static models. Consider structural and functional relationships in complex systems. Simplifications usually unavoidable when modelling. Processes being considered can vary Continue Reading
Summary
In this lesson, we have identified and defined what a model is. Understanding systems does not stop with our particular field. Looked at models in broadest sense and when/how best to apply particular model. Importance of verification and validation.
Steps to take when modelling
Brief overview of steps for tackling modelling process. What precisely is our problem and what do we want the model to do? Do we need a model at all? Perhaps it is too simple a task and we would sooner not waste time. Are similar models available? Can we buy Continue Reading