Unformatted text preview: of counters, … 3. Fall of a rain drop: The system consists of rain drop, cloud and ground. We can take it to be open system with air in the environment. The variables here are time, distance travelled, velocity, force etc. and the parameters distance between cloud and ground, etc. 4. Amul Factory: The system consists of milk procured and the various items, like chees, processed milk, Ghee, butter, yoghurt. What are the variables and parameters of the problem? 5. Demand of soft drink: If we predict the future demand based on the previous sales only, then it is a closed system. However demand may also depend on change in population, advertisement, and climate. Then these can be considered as objects in the environment and system as an open system. The relationship between ‘Sales’ ‘Profit’ and ‘Advertisement’ can be defined as follows: Advertisement Sales Profits So, it can noted that the same system can be closed or open depending upon the modeller. Degree of Detail: A system is a simplified version of RW, question arises how much simplification? For example, look at the examples 2 and 5, we have considered two models in each case. The second model is more detailed in each case. In the case of World Population problem one can simply consider the whole population as one object or one can consider them three categories – Young and juvenile, Mature and Child bearing and Old. This relates to degree of detail in system characterization. If we simplify it too much some important features may be lost and the results may either may not be adequate or of limited use (e.g. rain drop model – the first model was too simple and the second one did not consider the air drag hence we got results which were not useful). On the other hand if we include everything, the model may become unmanageable and again the results may be of limited use. Hence one has to make a sensible compromise. This is again a very subjective decision and corresponds to art aspect of modelling. Sometimes, we...
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This document was uploaded on 01/25/2014.
- Winter '14