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 of information in small amount of space Show relationships between […]

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 from simplistic to extremely complex, e.g .climate modelling. Time scales […]

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 one or use a pre-existing in-house one? Danger is discovering […]

Metaphors

Form of model used by humans to communicate. Still a form of abstraction. Used to represent something but not in literal sense – putting a complex explanation into simple terms. Examples: Food for thought Something that warrants serious consideration Lions lead by Donkeys German High Command description of the British Army in World War 1 A bird in the hand […]

System walkthrough and Consistency testing

System walkthrough Explaining model to another person/persons – enables modeller to focus on different aspects and to discover problems. Writing system documentation can have the same effect to by making to modeller look at model from different perspective. Consistency testing Check model produces similar results for input parameter values that have similar effects. Example: Network with two inputs, each with […]

Model Validation and Verification

Model is abstraction & consists of assumptions we make. In creation we remove unnecessary detail ¬†and focus on elements of system that are in important from desired performance point of view. Assumptions about system must be made during model construction therefore we must check that the model is a good fit. Process of robust model required two parts: design and […]

ERROR: Cannot find the file bin\ONSCLIENT.dll in the ORACLE_HOME

Trying to use the deinstall tool packaged with the Oracle 11.2.0.1 client¬†on one particular server failed and displayed the following output. C:\oracle\product\11.2.0\client_2\deinstall>deinstall Checking for required files and bootstrapping … Please wait … ERROR: Cannot find the file bin\ONSCLIENT.dll in the ORACLE_HOME C:\oracle\product\11.2.0\client_2. You must download the standalone version of the deinstall tool from OTN to deconfigure/deinstall this Oracle Home. cannot […]

A framework for models

Many different types of models but Ackkoff (1962) proposes three categories: iconic model – expected to behave same as real thing. e.g. scale model of ship or model aircraft in wind tunnel. analogue model – attempt to simulate behaviour without necessarily replicating physical appearance. e.g. computer games like Forza and FIFA. analytical model – developed from mathematical or logical relationships […]

Model Definition

Useful when considering situation without losing holistic viewpoint, example of modelling is boundary and environment diagram. The type of model used should be the best suited based on our understanding of the situation. A model is an abstraction of reality, to abstract is to summarise. Models are created because: Real life is complex – not just black and white but […]