Automated Systems, Robotics and Artificial Intelligence: Computer Science 0478 (Cambridge O Level / IGCSE)

An arcade in a shopping centre has a claw machine that lets a customer try to grab a prize from a pile of soft toys.

The machine works as follows: when a customer inserts a coin, a sensor detects the coin passing through the coin slot and sends this information onward. The next component checks this signal against the value stored for "one credit", and if it matches, it sends a signal that starts the motor turning the claw's controls and begins a 10-second timer for the customer's turn.

Which component of this automated system checks the signal against the stored value and sends the signal that starts the motor?

A poultry farmer keeps trays of newly laid eggs in an automated incubator so that they hatch successfully, instead of a farm worker checking on them by hand every hour, day and night.

Inside the incubator there is a temperature sensor and a small electric heating element, as well as a separate humidity sensor and a fan-driven water mister.

(a) Describe how the temperature sensor, the incubator's microprocessor and the heating element work together to keep the temperature inside the incubator within the correct range for hatching. [3]

(b) Give one advantage and one disadvantage, to the farmer, of using this automated incubator rather than checking and adjusting the eggs' environment by hand. [2]

(c) Name one scenario, other than agriculture, in which a sensor, a microprocessor and an actuator could be used together to form an automated system. [1]

A hospital pharmacy installs a machine to select the correct medicine packets from a wall of storage shelves and pack a patient's daily doses into an individual tray, a task pharmacy assistants previously did by hand for every prescription.

(a) State three characteristics of this pharmacy machine that mean it can correctly be called a robot, rather than simply "an automated machine". [3]

(b) Describe how the robot's sensors, microprocessor and actuators work together to select and pack the correct medicine into one patient's tray. [3]

(c) Give one advantage and one disadvantage, to the hospital, of using this robot instead of pharmacy assistants packing prescriptions by hand. [2]

The technology club at a school has an expert system installed on the computer that controls its 3D printer. When a print fails partway through, a student technician runs the expert system: it asks a series of on-screen questions about what the failed print looked like, and then displays a diagnosis of the likely fault together with a suggested fix.

(a) State the four components of an expert system. [4]

(b) For the 3D-printer expert system described above, explain how the interface, the knowledge base and the inference engine work together to reach a diagnosis. [3]

(c) Before the expert system was installed, the club used a single printed page of fixed yes/no troubleshooting questions instead. Explain one way in which using the expert system, rather than this fixed printed page, benefits the club. [2]

A gym's mobile fitness app suggests a personalised workout to each member. After every session, a member records how many repetitions they completed and rates how difficult the session felt. The app uses this growing store of data, together with machine learning, so that the reps and difficulty it suggests next time automatically become better suited to that member, without a programmer ever rewriting the app's code.

(a) State what is meant by machine learning. [1]

(b) Describe how the fitness app's behaviour is an example of machine learning, rather than a fixed set of rules written once by a programmer. [3]

(c) The gym also uses an expert system to help staff choose which of three standard injury-recovery plans to recommend to a member, based on the member's answers to a fixed set of questions about their injury. Explain one difference between this expert system and the machine-learning fitness app in how each one changes, or does not change, over time. [2]

(d) State one disadvantage of using machine learning, rather than a fixed set of rules, to decide a member's suggested workout. [1]

A remote weather station on a hillside has a temperature sensor, a rainfall sensor and a wind-speed sensor, all connected to a microprocessor. Every ten minutes the microprocessor reads each sensor and stores the values in a log file so that scientists can study long-term weather patterns later. The station has no motors, heaters or any other actuator, and it never changes anything in its surroundings by itself.

Which term best describes this kind of system?

A river authority operates two automated systems along the same river.

System 1, on a remote riverbank, has a water-level sensor connected to a microprocessor. Every 15 minutes the microprocessor reads the sensor and stores the value in a log file, which an engineer checks once a week to look for long-term changes in the river. System 1 has no actuator.

System 2, at a floodgate further downstream, also has a water-level sensor connected to a microprocessor, but here the microprocessor is programmed to open a motorised sluice gate (an actuator) automatically whenever the level rises above a stored threshold, and to close the gate again once the level falls back below it.

(a) State which system is a monitoring system and which is a control system, and give the key reason for each. [3]

(b) Give one reason the river authority might still want an engineer to check System 1's stored log every week, rather than removing System 1 and relying only on System 2's automatic gate. [2]

(c) Explain why System 2, but not System 1, needs an actuator. [2]

A car manufacturer replaces the human workers who used to weld car body panels together with a row of robotic arms. Each arm has a welding tool fitted to its end, sensors that detect the exact position of each panel, and a microprocessor programmed with the precise sequence and position of every weld needed for that car model.

(a) State two applications of robots, other than car manufacturing, where a mechanical structure, sensors, a microprocessor and actuators are combined in a similar way. [2]

(b) Explain how being programmable allows the same physical robot arm to be reused when the manufacturer starts building a completely different car model on the same production line. [3]

(c) Give one advantage and one disadvantage, to the workers themselves rather than to the manufacturer, of replacing the human welding team with robots. [2]

FreshPick Orchards has two sorting machines on its packing line, each fitted with a camera that photographs every apple as it passes.

Machine 1 is new. Before it was switched on, an employee spent several weeks looking at thousands of stored apple photographs and marking each one "Grade A" (sold in shops) or "Reject" (sent for juicing) by hand. Machine 1's software studied this large collection of already-marked photographs, and every week the employee adds that week's newly marked photographs to the collection it studies. Over several months, the proportion of apples Machine 1 sorts correctly has been getting steadily higher.

Machine 2 is older. Its software was given a single rule by a programmer when it was installed: measure the percentage of each apple's skin covered by brown marks in the photograph, and reject the apple if this is above 5%. Machine 2's accuracy at sorting apples correctly has stayed exactly the same since the day it was installed, no matter how many more apples have passed under its camera.

(a) Explain why the employee needed to mark thousands of stored apple photographs as "Grade A" or "Reject" before Machine 1's software could begin sorting apples using machine learning. [2]

(b) Explain why Machine 1's accuracy is expected to keep improving as more of each week's newly marked photographs are added to the collection it studies, whereas Machine 2's accuracy stays exactly the same however many more apples pass under its camera. [3]

(c) State what would specifically have to happen to Machine 2's software if FreshPick wanted it to become more accurate. [1]

(d) Give one disadvantage to FreshPick of using machine learning, rather than a fixed pre-programmed rule, to sort the apples. [1]

Space agencies send wheeled robot rovers, rather than astronauts, to explore the surface of Mars and collect samples of rock and soil. The rover carries sensors, a microprocessor and actuators, and is programmed with new instructions from Earth as each mission continues.

Which of the following is the strongest reason a robot rover, rather than a human astronaut, is used for this task?