Modelling Applications Lecture - 3 PDF

Modelling Applications Lecture - 3 1 Information Communication Technology Computer Modelling Computer modelling is creation of a model of a real system in order to study the behaviour of the system. This is also known as simulation. The model is computer-generated and...

Modelling Applications Lecture - 3 1 Information Communication Technology Computer Modelling Computer modelling is creation of a model of a real system in order to study the behaviour of the system. This is also known as simulation. The model is computer-generated and is based on mathematical representations. Its purpose is to try and find out how a system behaves, predict how the system will behave ahead of time and see if its possible to influence its behaviours. They are widely used in fields like: personal finance bridge and building design flood water management traffic management weather forecasting. 2 Information Communication Technology Advantages of Computer Modelling Using computer models is less expensive than having to build the real thing (e.g. building bridges) On many occasions it is safer to use a computer model (some real situations are hazardous, for example, chemical processes). Computer modelling allows you to try out various different scenarios in advance. It is nearly impossible to try out some tasks in advance in real life because of the high risk involved or the remoteness (for example, in space, under the sea, in nuclear reactors, when crash testing cars, etc.). It is often faster to use a computer model than do the real thing (in cases like climate change calculations, population growth, etc.). 3 Information Communication Technology Disadvantages of Computer Modelling A model is only as good as the programming or the data entered; the simulation will depend heavily on these two factors. Although building the real thing can be expensive, sometimes computer modelling is also a very costly option, and the two costs need to be compared before deciding which to use. People’s reactions to the results of a simulation may not be positive; they may not trust the results it produces (there will always be a difference between the results from modelling and reality). 4 Information Communication Technology Personal finance By using spreadsheet software, any type of modellings that can be done in mathematical form can be carried out. Spreadsheets are often used in some form to carry out financial modelling. 5 Information Communication Technology Bridge and building design When building a building or a bridge it is necessary to test the design before any construction work is started. By using 3D modelling various types of scenarios can be tested to ensure that final design meets the desired outcome. Simulations scenarios for bridge designs includes: Amount of traffic that might occur in case of accident The effect of weather and climate on the bridge Is the bridge earthquake proof? Can pillars supporting the bridge withstand the strong tidal waves. 6 Information Communication Technology Cont’d When testing the building using a computer model, a number of scenarios need to be considered: What is the effect of natural phenomena on the building The effect of a disaster, such as a fire – how does the structure stand up to such scenarios? how is it possible to move people around the building efficiently 7 Information Communication Technology Advantages of computer modelling in building bridges/buildings The design can be rotated in a number of different ways to allow different views of the design to be made. Building a bridge or building is expensive and dangerous if the final design had a serious flaw; modelling should allow any potential design flaws to be detected before any construction starts. Various scenarios can be tried out to see the effect on the design (see earlier list of scenarios). 8 Information Communication Technology Traffic Light Simulation When carry out traffic light simulation 3 things to consider: how and what data needs to be collected how the simulation is carried out how the system would work in real life 9 Information Communication Technology How and what data needs to be collected Since the data have to be as realistic as possible, data need to be collected at junctions for a long period of time. This is best done by using induction loop sensors which count the number of vehicles at each junction. Manual data collection is possible, but is prone to errors and is difficult to do over an 18-hour period per day (for e.g.) Data that need be collected will include: the number of vehicles passing the junction in all directions the time of day needs to be recorded along with a vehicle count how many vehicles build up at the junction at different times of the day how long it takes a vehicle to clear the junction data should cover weekends 10 Information Communication Technology How the simulation is carried out Collected data are entered into the computer and the computer model is run. Once the simulation’s traffic flow is similar to actual traffic flow, different scenarios can be tried out. Scenarios can include: Varying the timing of the lights and observing how the traffic flow was affected. Changing the number of vehicles stopped at part of the junction and then changing the timing of the lights to see how the traffic flow is affected. Increasing or decreasing traffic flow in all directions. Considering how emergency vehicles affect traffic flow at different times of the day. 11 Information Communication Technology How would the system work in real life Sensors in the road gather data and count the number of vehicles at the junction. This data is sent to a control box or to a computer. The gathered data is compared to data stored in the system (the stored data is based on model/simulation predictions which were used to optimise the traffic flow). The control box or computer ‘decides’ what action needs to be taken. Signals are then sent out to the traffic lights to change their timing if necessary. 12 Information Communication Technology