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Option B - Modelling and simulation

Question 1

HLPaper 2

Machine translators are regularly used to translate text from one language to another. In spite of the advances that have been made in this field, the output may still need to be proofread by a human.

Describe two problems that these translators may encounter when translating from one language to another.

Question 2

SLPaper 2

An old set of 2D animated cartoons from the 1940s has been discovered and it is decided to modify them to turn them into 3D animation.

1.

Define the term visualization.

[1]
2.

Outline the need for rendering in the creation of the animated 3D characters.

[2]
3.

Explain two technical implications of implementing a 3D animation in this way.

[6]

Question 3

SLPaper 2

Global warming is a term used to describe the increase in mean global temperatures.

There have been numerous computer simulations developed to predict the effects of global warming. One simulation is NASA’s Virtual Earth System Laboratory (VESL), which allows users to see how climate change affects glacier size, global sea level and changes to the coastline.

The VESL runs simulations in real time and is an abstraction of reality.

A recent study reported that previous simulations of predicted global sea levels for 2100 were highly inaccurate.

1.

Outline what is meant by a real-time simulation in the context of a glacier size simulation.

[2]
2.

Outline what is meant by the statement “the VESL simulation is an abstraction of reality”.

[2]
3.

Outline two reasons why predictions of global sea levels from simulations may not be accurate.

[4]
4.

NASA has decided to make its simulation software available for other scientists as well as members of the public.

Evaluate the social and ethical implications of this decision.

[6]

Question 4

SLPaper 2

Weather forecasters use computer models which are able to simulate future weather patterns. These forecasts were originally limited to the near future. However, modern systems can now produce long range forecasts.

The simulation of the weather forecasting models produces specific data which can be output in a variety of ways.

1.

Suggest two reasons why these simulations have improved both in their accuracy and their range.

[4]
2.

Suggest why forecasts become less accurate the more long range they become.

[4]
3.

Discuss whether historical data can be accurately used to forecast future weather.

[5]
4.

Define the term visualization.

[2]
5.

With the help of examples, discuss how the development in the way such data is visualized has made the results of these simulations more accessible to the general public.

[6]

Question 5

HLPaper 2

Google Translate is an algorithm whose function is to translate text from one language to another. One of the resources that it uses is the body of documents produced by the United Nations which are routinely translated by humans into various languages.

Discuss the reasons why Google Translate takes a probabilistic approach in preference to a cognitive rule-based approach.

Question 6

SLPaper 2

The electronic control unit (ECU) of a vehicle is an on-board computer that is constantly monitoring the performance of several components of a vehicle. For example, the ECU:

  • controls the functioning of the lights, the brakes, the airbag, and the fuel-level signal
  • permits the scale being changed in some digital displays, such as switching the speedometer from miles/hour to km/hour.

The software embedded in an ECU receives input data from a variety of sources when it runs auto-diagnostic tests.

1.

With relation to the activities that the software of an ECU has to perform, identify two of the sources that provide input data to the ECU.

[2]
2.

With relation to the activities that the software of an ECU has to perform, suggest one reason why the auto-diagnostic program in the ECU depends upon the make and model of the vehicle.

[2]
3.

Vehicles are tested for their exhaust gas emissions using simulation software at specialist garages. During a period of 5 minutes, a vehicle with the engine switched on is monitored for emissions of carbon dioxide (CO2) and fine particulates. The software uses 3D visualization techniques to display these parameters on a screen for the whole duration of the test.

Explain how emissions of CO2 and fine particulates could be represented in 3D by the software.

[4]

Question 7

HLPaper 2

Neural networks are often used to model the complex behaviour of systems. These networks must first be trained in order to establish a reliable model. One such method of training makes use of supervized learning algorithms.

1.

Outline the basic steps involved in supervized learning algorithms.

[4]
2.

The following block diagram illustrates a neural network used by a supervized learning algorithm to calculate a resulting value RES, for a given set of inputs.

The neural network in the block diagram contains 60 nodes in the input layer (block I), 36 nodes in the hidden layer (block H) and 6 nodes in the outermost layer (block O). The solid black arrows indicate that all nodes in one layer are feeding all nodes in the successive layer. In particular, the value RES is calculated by using all nodes in O.

Calculate the number of weights that the above neural network uses in producing a value for RES. Show the details of your calculation.

[2]

Question 8

SLPaper 2

In a small shop two people prepare and sell bread rolls. The space for preparing the bread rolls is small. This space includes a sink and a cash register. Each of the ingredients used to fill the bread rolls is kept in a separate bowl with its own fork or spoon. Sometimes the bowls need to be refilled.

Preparing a bread roll requires the following steps:

  • slice the bread roll
  • spread its base with some sauce
  • add lettuce
  • fill with at most two chosen fillings
  • cover the roll with the other half
  • wrap it in paper.

After that, the roll is ready for payment and collection.

Even when the shop is busy, each person only prepares one bread roll at a time.

A larger restaurant is already using simulation software for the preparation of their dishes.

The restaurant has a menu with eight possible dishes. These dishes may require a number of steps such as cutting, mixing, boiling and grilling to prepare them, as well as different cooking times. The restaurant has a cook and an assistant who prepare one dish at the time.

1.

Outline two problems with this method of preparation that could affect the time it takes the two people to prepare an order.

[4]
2.

Describe how the two people could improve the efficiency of their work, without compromising on the quality of service to the customers.

[3]
3.

Explain the difference between a model and a simulation.

[3]
4.

Identify three elements that the simulation software might consider, in addition to the information already described above.

[3]
5.

The simulation program will group all orders received in an interval of 10 minutes. The program will then produce a sequence of all the cooking steps so that these orders can be completed as quickly as possible. Once the kitchen has completed the orders for one interval, it is ready to accept orders for the next interval.

Customers are impressed by the rapidity of service, but not by the quality of prepared food.

Suggest two elements that the software simulation may have not considered that may lead to complaints from the customers.

[6]

Question 9

SLPaper 2

The rise in global temperatures has led to the melting of the sea ice in polar regions. Scientists have developed a number of computer models that can be used to make predictions about the rate of sea ice melting in these polar regions and its effect on coastal areas globally. In order to create a computer model a number of variables are identified.

A computer model of the effects of the melting of the sea ice in the Arctic Ocean may include the following variables:

  • average ocean surface temperature (°C)
  • albedo of the ocean (the proportion of light reflected from the ocean surface)
  • precipitation (mm)
  • salinity of the ocean (grammes of salt in one kilogramme of water)
  • area of sea ice (km2).

In this model the following rules have been determined:

  • for every 0.01 °C increase in ocean surface temperature, the area of sea ice decreases by 1 %
  • for every 1 % decrease in the area of the sea ice, the sea level rises by 20 mm.

The initial values are:

  • area of sea ice = 1 000 000 km2
  • average surface temperature of the ocean is 0.00 °C.

The scientists observed when running the model numerous times using historical data there were significant differences between observed and expected results.

A second model was developed that included new variables and rules.

The surface of the ocean reflects the heat from the sun. The ratio between the area covered by the sea ice and the area where there is no sea ice (open ocean) affects the value of the average albedo. The lower the albedo, the quicker the sea ice will melt.

The average albedo is calculated using this formula:

Average albedo =

(areaofseaice×albedoofseaice)+(areaofopenocean×albedoofopenocean)(areaofseaice+areaofopenocean)

Note:

  • area of sea ice = 1 000 000 km2
  • area of open ocean = 1 000 000 km2
  • albedo of sea ice = 0.6
  • albedo of open ocean = 0.1.

The average albedo will change with every iteration of the model. Each iteration is 2 years after the previous.

The rules for the model are:

  • the initial albedo is 0.35
  • the rate of decrease in sea ice every 2 years is0.3averagealbedo2
  • the starting year is 2019
  • the sample rate is every 2 years.
1.

Copy and complete the following table showing each variable’s data type and a suitable range of values that would represent the information shown above.

[3]
2.

Using the rules and initial values above, construct the pseudocode that would enable the area of the sea ice and the sea level rise to be calculated if there was an increase of 0.04 °C in the ocean surface temperature.

[4]
3.

Using the information above state the area of the sea ice.

[1]
4.

Using the information above state the change in sea level.

[1]
5.

Using the formula, rules and initial data given above, construct the pseudocode that would calculate the year that the area of sea ice will be less than 10 000 km2.

[7]
6.

Identify two ways that this model could be implemented.

[2]
7.

Explain why the accuracy of the simulation in predicting the area of the sea ice is critical.

[3]

Question 10

SLPaper 2

Simulation software can be used to produce a 3D visualization of rising sea levels that change as the user alters the percentage of ice that has melted.

Figure 3: 3D visualization of rising sea levels

[Source: Courtesy NASA/JPL-Caltech.]

1.

Define the term visualization.

[1]
2.

Identify how a 2D visualization could be used in this scenario.

[1]
3.

Explain the benefits of using visualization when simulating rising sea levels.

[5]
4.

Once the 3D visualization has been rendered, when the user drags a slider bar to simulate the amount of ice that has melted, the visualization is re-rendered without any delay.

Figure 4: Slider bar to simulate different percentages of sea ice

[Source: Courtesy NASA/JPL-Caltech.]

[6]
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