Spreadsheets, modelling and simulations


Modelling


A computer model is a program which has been developed to copy the way a system in real life works
A model defines the relationship between two or more things.
It makes use of mathematical equations to define that relationship.
The main point of a model is to make predictions.
A model is produced to represent a real situation using the variables and the relationships between the variables. When testing a model, typical inputs are used and processed to check if the output actually is closely aligned to the real situation.


Simulation


A computer simulation is a program which not only models the system but also uses equipment to provide a physical experience. A Simulation tries to copy or mimic something that can happen in our physical world. A simulation uses the model and by accepting a range of inputs, processes the data and outputs based on the variables and their relationships. The inputs may or may not ever occur in reality. The outcomes of various "what if" situations are produced by processing the various inputs. Some of these situations reflect what would happen under normal circumstances. Other inputs can be used to predict results in situations that in reality are unlikely to occur.

Model versus Simulator?

The question is when is a "flight simulator" a model and when is a "flight simulator" actually a simulator? The name is confusing.
A "flight simulator" is a model is created by a company and is programmed with the variables and relationships to fly a particular kind of plane under various conditions. The variables, relationships and sample input are collected from real situations or what is perceived to be the real situation. This is the model.
When a trainee actually uses the "flight simulator" and reacts to the various situations that are presented to them during the flight simulation, then the reactions of the trainee are inputs into the model (IT system) that determine the output of the flight simulator (how well the simulated plane takes off, flies, lands). The trainee receives feedback from the flight simulator how well they flew the plane compared to what the model has stored as the ideal result.
(reference occ Barbara Stefanics)




Notes on Modelling and Simulation


Some excellent examples of simulation
Greenhouse simulator

Simulation

What are Demographic and Environmental Simulations?
Demographic simulations explore the growth and development trends of humans in a certain area. Demographics chart the birth rate, infant mortality, income, and population density rates as well as the gender, racial, and ethnic groupings in a given area. These charts can show the changes in a particular area over a given period of time. The data collected from demographic studies can then to try determine why the rates and groupings are the way they are so changes can be made to that area or other areas to try to make and improvement and/or meet social goals. Then, based on the figures collected from these demographic studies, simulations can be conducted to determine the future outcome of that particular area with changes being made, or left as an isolated area without change.

Environmental simulations explore the trends within a particular area of the environment. These simulations chart the growth/reduction rates in the size of the environment, the change in landscape, water, and air quality as well as the species of animals/plants in the area, the amount of human interaction and the positive and negative effects of human occupation in/around the area. Environmental studies can determine the manner in which the environment has changed and the factors that play a part in changing it. With this data, environmental simulations can be programmed to predict the condition of the environment in a given amount of time due to changes in weather, climate, human interaction and/or natural disasters.

IT Systems
Simulations often rely on computers to process large amounts of mathematical and statistical data to create models of real life. These computers generally have several CPU's to process every variable and factor that goes into predicting future trends and developments that are set up by researchers. Sometimes, the simulations and models are very graphically detailed, so a high definition monitor or other visual output device is used to visually interpret the abstraction. The system also needs to use specific software that combines the algorithims for use in simulations. This software may be comprised of several spreadsheets, database programs, or specially designed software made by programmers.

Advantages
Demographic and environmental simulations have several advantages:

Weather Prediction
Through the collection of data and years of observation, weather models and simulations can accurately and easily display weather patterns, which can help prepare communities for hazardous weather or oncoming disasters, thus saving lives.

Economic Development
Demographic models and simulations can chart and predict the movement of people into and from different areas of a country or region. By looking at the developing industries and commercal sites in the area, growth or decline can be seen in a particular region.

Human Impact
By watching the movements of people and determining the types of impact a particular group causes on the environment, models and simulations can be made that depict the future of an area. Based on these simulations, certain industries and people could or could not be allowed in a particular area because of their negative impact upon the environment.

Disadvantages
Demographic and environmental simulations also have several disadvantages:

Inaccuracies
Sometimes these simulations do not account for every possible variable that effects the environmental or demographic trends. Demographic locations vary depending on many factors like religious ties, family history, availablity of work and education, quality of life, etc. The environment operates upon a myriad of factors that create each individual ecosystem that is balanced to finely.

Dependence
Researchers could become glued to the facts that are presented in their models rather than simply looking around and getting the feel of an area. Social mores and moods cannot be quanitfied for the use in simulations, nor can the changes in such areas

Social and Ethical Issues
Demographic and environmental simulations effect the everyday lives of people in several ways:

People and Machines
Simulations are run mostly by humans, but their results often effect how we as humans develop in our environment based on our probable impacts and population density of an area. These simulations produce results that we base our decisions from, sometimes instead of using general textbook guidelines or sheer experience.

Reliability
The reliability of the information that is input into a simulation and the reliability of the result easily determines how we react to the predicted situations. Sometimes, the machines do not process the information correctly, the information is bad in the first place, or there is simply not enough information to make a reasonable judgement.

Examples of Simulation
Internet games like checkers, hearts, reversi, in which you play against an opponent who is not actually physically there with you, flight simulations.Many military bases with the use of modelling and simulation, are able to practice and predict what will happen in the air.

Visits the sites and attempt all activities:

http://www.kenttrustweb.org.uk/kentict/kentict_soft_simul.cfm

http://www.forgefx.com/demos.htm
http://itgsopedia.wikispaces.com/3.8+Spreadsheets%2C+modelling+and+simulations


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