Home / IB DP Computer Science Topic 7: Networks -: 7.1 – Control HL Paper 1

IB DP Computer Science Topic 7: Networks -: 7.1 – Control HL Paper 1

Question

Cars have many automated features to improve the driving experience. One example is the use of headlights that automatically switch on and off.

Some cars have adaptive cruise control. This uses RADAR technology and a processor to ensure the car stays the same distance away from the car in front.

A system with many functions operating independently could be managed using either centralized or decentralized processing.

As vehicles become fully autonomous (self-driving), ethical considerations must be taken into account when designing software.

a.)State one input device used by the automated headlights.[1]

b.)Explain how the interaction between the inputs, processing and the outputs of the feedback loop ensure the car stays the same distance away from the car in front.[6]

c.)Discuss the use of centralized and decentralized processing in the context of control systems such as those involved in the operation of motor vehicles.[5]

d.)Explain one ethical concern that must be considered in the development of autonomous vehicles.[3]

Answer/Explanation

Ans:

a.)

photoelectric sensor;
light sensor;

b.)

Sensor (continuously) collecting data (related to the distance between the two vehicles);
Data is converted to digital using ADC…;
…and sent to the processor;
Processor has access to pre-set data (minimum distance required between the two cars);
Processor compares the input data against stored/pre-set data;
If the vehicle is too close, the processor sends a signal to an actuator to apply the brakes/ an output signal (for example, warning light on the dashboard/ audible warning) to the driver to apply break;
If the car has fallen back from the car in front, the processor sends a signal to an actuator to apply acceleration/ an output signal to the driver to apply acceleration;
This process is constantly looped (feedback loop);

c.)
Centralized processing would allow the different features of the car to be controlled by a single processor;
… this means that different features of the car are less likely to impact on the operation of other features, as the central processor can coordinate them;

Award [2 max] for decentralised / distributed processing
Decentralized processing allows each of the car’s features to have its own processor;
… enabling each feature to function independently/more quickly;Centralized processing is more complex for the manufacturer to program, but is possibly safer as the different components coordinate;
Centralised processing is more expensive to achieve as the whole system needs to be coordinated in real time;
Decentralised processing has a faster response (time due to the use of multiple smaller PLCs);
Decentralised processing is simpler/cheaper for the car manufacturer as they can use standard parts that are already programmed, but it is more difficult to get them to coordinate with each other;
Decentralised processing allows scalability, the subsystems can be easily customised;
A crash in a centralized system would result in failure of the whole system / a critical system failure so would have far greater consequences than in a decentralized system where the system may be able to partially function hence are riskier than decentralized ones;

d.)

Autonomous vehicles can be seen as more dangerous to pedestrians/cyclists;
…as they have to be programmed to react to avoid unpredictable movements from them;
The ethical consideration is how might the processor decide whether to avoid the cyclist to hit a pedestrian instead (trolley problem);

When autonomous vehicle control systems are perfected;
… they should be safer than human drivers;
… it may then be an ethical consideration as to whether a human who cannot drive should be the responsible person in the autonomous vehicle?;

An autonomous driving system could collect detailed information about the movements of the car;
… this information could reveal where individuals go, and raise privacy concerns;
… which could be exploited for commercial gain/ be considered as a form of surveillance (an ethical consideration);

There may be times when an accident is unavoidable (the trolley problem);
The autonomous vehicle has to make a ‘decision’ about who to hit;
In this case is the driver, the manufacturer, the software engineer or the third party accountable?;

Note to examiners: accept other reasonable answers.

Question

A rail transport company uses a global positioning system (GPS) to determine a train’s position.

The GPS data is used to provide real-time arrival data on video displays in train stations.

The GPS data is made publicly available so that software developers can use it to build apps.

The mobile application ATrainAway uses the real-time train GPS data as well as the GPS data from the user’s smartphone.

a.Explain how GPS works. [4]
b.i.)State one data item concerning the arrival of a train that may be provided on the video display.[1]
b.ii.)Outline how sensors can be used in combination with GPS to provide more accurate arrival data.[2]
c.)Outline two pieces of information that the ATrainAway application could provide to the user.[4]
d.)Discuss the advantages and disadvantages of using GPS in transportation systems.[4]

Answer/Explanation

Ans:

a.)
The GPS receiver in a train takes the information from the satellite/ picks up the signals from (at least) 3 satellites;
The signals transmitted are: time of transmission, coordinates of the satellite;
The difference between the (atomic) time of transmission and (atomic) time of receiving the signal is used to calculate the distance;
The method of trilateration is used to determine position from the distance to satellites/ is used to determine the train’s exact position/ is used to calculate position of the train through equation resolution on a sphere;

b.i.)
Train number/ route / direction;
Status (on time / delayed / cancelled);
Time train / next train are due;

b.ii.)
Motion sensors/vibration sensors (can be placed on track rail);
(Accept any sensors which detect trains that pass them!)

(Sensing devices are placed) at a distance from each side of a train station/junction
OR
at some fixed points where obstacles (like tunnels) prevent GPS from working properly;

Data from each sensor can be logged continuously and used in calculations/determinations (of expected arrival times/ delays / rerouting during disruption, etc.);

c.)
Real-time information (train number/ route / direction and status (on time / delayed / cancelled);
relating to the arrival / departure of a particular train;

The time next train is due (the next 2/3 times a train will arrive at the station);
helps passenger to spend less time waiting on trains;

Should save user’s (passenger) most frequented stops and routes;
for quick access to get the next rail trip;

Alerts (set);
to let you know when a train is nearing the station;

Trip planning (conducted);
through Google trip planner within the app;

Information on the nearest station, distance to station/ next train arrival/ next train departure;
to help passenger to spend less time travelling/ save time;

d.)
Safer transit;
Trains are tracked and in case of emergency the location can be reached at the earliest and emergency services provided;

More favourable view of transit/helps passenger to get punctuality status of the train/;
GPS can provide worldwide three-dimensional positions (24 hours a day) (in any type of weather);

Sometimes it is too difficult to ensure reliable positioning;
Objects, such as buildings, overpasses, and other obstructions (that shield the antenna from a satellite) can potentially weaken a satellite’s signal;

Privacy issues;
Knowing the absolute position of anything, anytime, anywhere;

Question

Outline one feature of autonomous agents.

Answer/Explanation

Ans:
Reactive behavior;
autonomous agent senses the environment and reacts;

Autonomy;
autonomous agent activates alone for a task / is not invoked for a task / selects the task itself / operates without human supervision;

Persistence;
autonomous agent is a programmed device and the software describing an agent runs continuously;

Sociality;
autonomous agent can interact with other agents through communication / it can work in coordination and cooperation with other agents;

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