Software Development

VCAA Exam Post Mortem

2013

Other VCE IT Exam Post Mortems to enjoy

IPM / ITA / Informatics / Data Analytics - 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2023

Info Systems / SD - 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2023

Case study

CASE STUDY INSERT FOR SECTION C
Please remove from the centre of this book during reading time.

Case study

An organisation called the Protection of National Parks and Wildlife (PNPW) is responsible for monitoring the health of native animals and controlling wild animals across all national parks in Victoria. Currently this is achieved in three ways

• a network of animal-monitoring stations located in the national parks, where park rangers monitor animal activity on a weekly basis
• the use of aircraft to actively locate animals using heat-detection cameras in the very remote areas
• reports from staff who work in the parks, the general public and other emergency service organisations

As a result of recent budget cuts, PNPW needs to find ways to reduce its costs. The animal-monitoring stations are important and relatively inexpensive to run. However, the use of aircraft requires the hiring of several aircraft and pilots every week.

Brenda Benbow, the manager of PNPW, has been working on a plan for using a drone (an unmanned aircraft) to monitor the native animals. This will cut down on the annual cost associated with the hiring of aircraft and pilots.

She has chosen a model that can pilot itself once it has been given simple instructions. This model is fitted with a standard micro-video camera, an infra-red camera and global positioning system (GPS) technology. It also has two communication channels: a standard wireless network interface card and a radio transmitter/receiver. The radio has a range of about 50 km.

Each drone will be placed at a rural airfield. When a drone has to make a flight, it will be sent flight instructions from PNPW headquarters in Melbourne via a PNPW officer's notebook computer. The PNPW officer will then launch the drone from a car at the airfield.

Once airborne, the drone will fly its preset patrol path. It can detect hotspots as small as 20 cm in diameter. This means that it can 'see' most wildlife. On detection of a hotspot, the drone will interrupt its preset patrol path, start monitoring the hotspot and pass control to a tablet computer at the nearest monitoring station. The drone will also transmit what it is 'seeing' to the tablet computer. The tablet will use wi-fi to communicate with the drone through the monitoring station's wi-fi router. The router uses the national park's communication system to communicate with the drone. The park rangers who are monitoring animals will then decide whether or not the picture shows an animal that requires further monitoring.

Brenda has hired Drone Solutions to develop the software for the new Aerial Animal-Detection System (AADS). She has provided the company with details of the drone operation, the hardware resources contained on the drone and the requirements of the software operation. Software will have to be written for the computer at PNPW headquarters, the drone and the tablet computers to be used by the park rangers.

END OF CASE STUDY INSERT FOR SECTION C

Question 1 (3 marks)

Drone Solutions has determined that it has four months to develop the software solution for the Aerial Animal-Detection System (AADS). Melanie, who is leading the development team at Drone Solutions, has prepared a chart to help her monitor all aspects of the project.

a. Melanie will use the chart to monitor the tasks required to complete the project. One of the major tasks she has scheduled on the chart is designing the AADS software.
Outline two tasks that you would expect to see scheduled before the software design task. 2 marks [4 lines for each task]

The exam should have bolded the word "two" in the question.

• Determine the constraints on the solution.
• Determine solution requirements - functional and non-functional.
• Define the scope of the solution.

Note: This is a classic "What do you do during the PSM analysis phase?" question.

Average mark: 1.2/2 (60%)

Tasks that related to understanding/identifying the solution requirements, solution constraints and solution scope where appropriate.
It was encouraging to see that students were able to identify that this question asked for tasks that occurred during the analysis stage of the problem-solving methodology. It was important to note that the question required a task. This meant that an action word (for example, create, interview, determine, write, etc.) needed to be provided within the response.
The following are examples of appropriate student responses.

Prepare a Software Requirements Specification (SRS) which will be used in the later stages of the project.
Collect data that would assist in the creation of the AADS, which could range from interviewing rangers to researching similar systems.
Determine the solution requirements. This includes the functional requirements of the AADS (what it must do to meet the goals of the solution) and the non-functional requirements (the qualities of the AADS).
Determine the scope of the solution. This sets the boundaries as to exactly what AADS will do and equally as important, what it won’t do.

b. In addition to monitoring the tasks required to complete the project, identify one other area that the chart should monitor. 1 mark [2 lines]

• Resources.
• People.
• Time.

Note: This is a simple "What does project management monitor?" question, excluding "tasks."

Average mark: 0.6/1 (60%)

The chart could also monitor resources, people or time.
Most students were able to identify one of these elements of project planning.

Question 2 (5 marks)

Melanie has started a data dictionary for the context diagram (Diagram 4). It is incomplete.

a. Complete the table below by writing the appropriate data flow names from the context diagram into rows 3, 4 and 6. 3 marks.

The examiners kindly completed the flight_log row so you would see that it could not be the answer to one of the other questions. Nice of them!

Average mark: 2.3/3 (76%)

The majority of students were able to interpret the elements of the context diagram; however, students should ensure that they use the examples in the table and text provided in the diagram to assist in formulating accurate responses; for example, image_data is a more accurate response than image or picture data, etc.

b. To state the position of any animal found, longitudes will be entered as numbers, for example, 97.73858. When creating the data dictionary for individual data items, Melanie has a choice of setting longitude to 'integer' or 'floating point'.
Which should she choose? Justify your response. 2 marks.

choice [1 line]

Floating point.

justification [4 lines]

The numbers contain a fractional part, and integers cannot hold these.

A pretty easy way to earn 2 marks. If you needed 4 lines to justify your choice, something is going wrong!

Average mark: 1.6/2 (80%)

Most students were able to identify ‘floating point’ as the most appropriate data type for storing longitudinal values, as they required the use of decimal values.

Question 3 (3 marks)

Software will have to be written for the PNPW computer, the drone and the tablet computers to be used by park rangers. Melanie has worked out the main processes for the AADS. These are shown and numbered in the incomplete data flow diagram (DFD; Diagram 5).

Which process will run on each of the computer systems below? (You may write just the process number.)

the PNPW computer - (1) plan flight

the drone - (3) control flight and detect hotspots

the tablet computers - (2) visualise telemetry data

Note - it's pretty easy to find the named external entities in the DFD and trace the outgoing arrows back to the circles of their related processes.

Average mark: 2.5/3 (83%)

the PNPW computer: 1 – plan flight
the drone: 3 – control flight and detect hotspots
the tablet computers: 2 – visualise telemetry data
Most students were able to interpret the data flow diagram (DFD), and many took advantage of simply listing the number of the process involved.

Question 4 (3 marks)

Melanie has not yet labelled the data flows in her DFD (Diagram 5).
What labels should be shown on the data flows A, B and C?

A - Visualised telemetry data

B - Flight Command

C - Patrol Path

Note: This question may look like a scary DFD question, but it's really quite straightforward.
A - the 'A' arrow goes to the park ranger. Looking at the context diagram, what is the only data flow to the park ranger? Visualised telemetry data!
B - In the DFD, the B arrow is the only data going to the drone. What data is flowing to the drone in the Context Diagram? Flight Command.
C - What data is flowing from the HQ staff? Look at the Context Diagram... Patrol Path.

It's much easier if you remember that the DFD is actually just details of processes within the Context diagram's circle. Notice that both the DFD and CD show the same external entities (park ranger, HQ, drone), so their data flows can be read together to get information about flows within the system and between the system and its partners.

It's a good question to test students' understanding of the relationship between a CD and a DFD.

Average mark: 0.9/3 (30%)

The data flows should have been labelled
A: visualised_telemetry_data
B: flight_command
C: patrol_path
Again, students should have taken advantage of the text provided in the diagram to assist in formulating an accurate response; for example, ‘telemetry data’ is not as accurate as ‘visualised_telemetry_data’.

Question 5 (4 marks)

The data store in Melanie's DFD will contain a sequential list of global positioning system (GPS) coordinates. The coordinates will be entered in flight order, with the first coordinate entered being the first point the drone flies to. Before take-off, more points could be added to the end of the list if required.

In her design notes, Melanie has indicated that this data store should have a stack structure. A colleague suggests that it should be a queue data structure.
Which would you choose? Justify your choice.

choice [1 line]

Queue.

justification [6 lines]

You want the entries to come in the order in which they were entered - the first datum out of the structure should be the first point to fly to. A queue, being First In First Out (FIFO) behaves like this.

A stack, however, would return the last-entered coordinates first, and end with the starting coordinates, because it is a First In Last Out (FILO, or LIFO) structure.

Note - It's easy to remember...

• A queue is like a human queue: the first person in the queue is the first to be served and get out.
• A stack is like a stack of dinner plates in the cupboard. The last one added to the pile is the first one to be taken from the pile at tea time.

Queue - FIFO	Stack - FILO	Dog - FIDO

Average mark: 2.6/4 (65%)

Queue data structure
Students should have noted the requirement to justify their response, and that four marks had been allocated. In general, a response that provided the correct choice, provided a justification for a queue data structure or stack structure and correctly applied the response to the case study obtained full marks.
The following are examples of high-scoring student responses.

Choice: queue
Justification: As the first coordinates entered will the first points the drone flies to, queue would be the most appropriate data structure, as it goes by the rules ‘first in first out’ as compared to a stack which goes by the rule ‘last in first out’ which would not be appropriate as this would cause the last coordinate being entered to be the first point the drone flies to.
Choice: queue
Justification: Since the queues have a ‘first in first out’ nature, this would satisfy the ‘first coordinates entered being the first point the drone flies to’ statement. Melanie’s choice would be incorrect as a stack follows the ‘first in, last out’ principle, which would not satisfy the required method stated.

Question 6 (5 marks)

George, one of the programmers for Drone Solutions, has been doing some research on the internet and has found some software, written for a drone, that was developed overseas. He downloads the software and begins altering it. Melanie sees what he is doing and orders him to look up the code of ethics for Drone Solutions.

a. Explain the purpose of a code of ethics. 3 marks. [7 lines]

It lays down the rules for acceptable behaviour for members of a group so they are all aware of what is appropriate and what is not. This can prevent breaches of the rules due to honest ignorance of them, e.g. by newcomers. It also lets the group leaders sanction rule breakers since they had no excuse for misbehaving.

A code of ethics also serves to uphold the public reputation of a group. It also bonds its members in a comraderie born of shared ideals.

Average mark: 1.3/3 (43%)

In general, students were able to give some information about the purpose of a code of ethics; however, many found it difficult to expand their response to provide adequate detail and depth for full marks.
The following is a possible response.

A code of ethics outlines values and principles that should be upheld by stakeholders. A code states what is acceptable behaviour and can provide guidelines for resolving ethical dilemmas. They are not laws but rather values that help professionals make decisions about going about their work.

b. What should George do to resolve this ethical dilemma? 2 marks [7 lines]

• Seek permission to use the software from its author/owner.
• Pay for the software, if it's commercial.
• Throw the software away and start his own version.

Once again (they did it in the 2013 ITA paper, B8c) the examiners have just assumed there is an ethical dilemma with no due explanation. The case study did not say whether the software was commercial, freeware, Open Source, GNU licensed or whatever. Did Melanie even ask the status of the software?
If the software were commercial, it would be a copyright issue, and there would be no ethical dilemma because his use of it would be a legal matter, not an ethical one.
If there is an ethical dilemma in the situation, why not give enough information for the students to determine what the dilemma is? Then ask them to say what it is, and then ask how to resolve it.

Not a good question.

Average mark: 0.5/2 (25%)

Students needed to discuss using the code of ethics and/or decision support frameworks to help resolve the ethical dilemma.
Many students found it difficult to identify the ethical dilemma of whether George should use the code; instead they concentrated on the illegal downloading of the code. Many responses incorrectly stated ‘just stop using the code’ as the way he could resolve the dilemma. Students are reminded that answers should apply to the case study.
The following is an example of a high-scoring student response.

His ethical dilemma is that if he uses the software off the internet without permission, he could be in breach of the Copyright Act 1968, but by using the software it will make the development process of the software be much quicker (more efficiency). To resolve the ethical dilemma, George must consult the company’s code of ethics and decision support framework to see what the best method to go about creating the software is, and to see what company policy says about using other people intellectual property.

Question 7 (5 marks)

When a drone detects a hotspot (a temperature above 20°C), it immediately interrupts its preset patrol path and begins monitoring the hotspot. This new path will allow the drone to continuously view the hotspot. This is done in a function called StartMonitoring. It will continue to monitor for five minutes before returning to its patrol path unless told to continue monitoring or to resume its patrol path immediately. This message is received in a variable AlertReply. If told to continue monitoring, it will do so for five minutes or until another AlertReply is sent. When it has finished monitoring, it automatically resumes its patrol path using a function ResumePatrol.

The following is a section of the algorithm.

Get DetectedTemp
If DetectedTemp > 20 Then
    Call StartMonitoring
    FinalTime CurrentTime + 5mins
    Send Alert
    Repeat
        Get AlertReply
        If AlertReply = Monitor Then
            FinalTime CurrentTime + 5 mins
        Endif
    Until (CurrentTime > FinalTime) And (AlertReply = Patrol)
    Call ResumePatrol
Endif

a. George decides to desk check the loop in this algorithm by using various values of CurrentTime and AlertReply to see if the loop behaves as required.

Complete the following table if the value for FinalTime on entering the loop is 11:00 am. 3 marks

Working space [ about 6 empty lines of space]

Repeat	TEST 2	TEST 3	TEST 4
Values on loop entry	CT=10:58. FT=11:00	CT=10:58. FT=11:00	CT=11:04. FT=11:00
Get AlertReply	Monitor	Patrol	NULL
If AlertReply = Monitor Then	True	False	False
FinalTime CurrentTime + 5 mins	FT = 11.00 + 5 = 11:05	(skipped)	(skipped)
Until (CurrentTime > FinalTime) And	10.58 > 11.05 ? False	10:58 > 11:00? False	11:04 > 11:00? True
(AlertReply = Patrol)	False	True	False
So...	False AND False = False, so loop repeats	False AND True = False so loop repeats	True AND False = False so loop repeats
Observation...	Drone monitors	Drone monitors	Drone monitors

Note - This is how I do deskchecks - beside each line of code I put down the state of variables and logical tests after that line is executed.
Each loop, or each test gets its own column.
In this way it's harder to overlook little factors that can have a significant effect on the answer.

Average mark: 1.6/3 (53%)

Similar types of questions have appeared in past examinations. In this question, students were required to provide the action observed in each test; many missed this and wrote about the change to variables or that the drone continues on its path.

b. Identify the major logic error in this algorithm. 1 mark [4 lines]

The ending condition of the loop is incorrect. The drone should should continue monitoring until the final time is reached or the AlertReply tells it to resume its patrol.

Average mark: 0.5/1 (50%)

Many students identified that the algorithm required both conditions (time expired and resume patrol) to be true, but only one needed to be true to resume the patrol.
The question asked students to identify the problem. It was not sufficient to only write the line of code containing the error without some explanation.

c. Rewrite one line of the algorithm to correct the major logic error. 1 mark [2 lines]

Until (CurrentTime > FinalTime) Or (AlertReply = Patrol)

There's quite a lot of work involved in answering his question. I thought it was worth more than 5 marks!
Still, I appreciate the working space provided for the students to do their thinking so they don't have to squeeze notes into the margin of the answer book, or use the empty back pages.

Average mark: 0.5/1 (50%)

Many students were able to identify that the AND needed to change to an OR in the UNTIL statement.
The following is an example of a correct response.
UNTIL (CurrentTime > FinalTime) OR (AlertReply = Patrol)

Question 8 (3 marks)

George says it will not take him long to create the screen design for the software on the tablet that will be used by the park rangers, as the screen design will be easy and everyone uses tablets these days.

Outline one concern with George's approach to the screen design and suggest what George could do to ensure that his screen design is effective. [7 lines]

His assumption that "everyone uses tablets" is incorrect, so he may design the software carelessly, making it hard to use by those who don't know how to use tablets.

He should consider the needs of all types of users - especially those unfamiliar with using tablets - to make the software as easy to use as possible, while not inconveniencing skilled 'power' users.

During the design process, he should get the input from skilled and unskilled tablet users to reveal potential problems with his design ideas.

Average mark: 0.6/3 (20%)

The majority of students were not able to outline a concern such as ‘George is not taking the skills or knowledge of the animal spotters into consideration’ and instead wrote lengthy responses about elements of the user interface. Ideally, responses should have identified a concern (not seeking input from spotters), and discussed two methods for gaining input (before design) or feedback about the design from the spotters.

Question 9 (5 marks)

Before a park ranger can give directions to a drone via the software on a tablet computer, they must enter a username and password.
Using the variable names Username and Password, write an algorithm that accepts the username and password entered by the user, and checks that they match the variables CorrectUserName and CorrectPassword.
If they are correct, the algorithm should start the monitoring program, and if not, it should display an 'incorrect username/password' message. [7 lines]

DISPLAY "Username?"
GET Username
DISPLAY "Password?"
GET Password

IF (Username = CorrectUserName) AND (Password = CorrectPassword) THEN
    CALL MonitorProgram
ELSE
    DISPLAY "Incorrect username/password"
ENDIF

Hmmm. Rather basic and repetitive: the previous question has already exercised students' knowledge of AND and IF.
Surely a different nugget of programming wisdom could have been tested here? It's not as if we're short of them...

Average mark: 2.9/5 (58%)

A complete algorithm is shown below. Other answers were also possible.

Get (or Read) UserName and Password
IF UserName =CorrectUserName AND Password = CorrectPassword then
Load Monitoring Program
Else
Display incorrect username/password message
ENDIF

Students were expected to use the information provided in the text of the question to develop an algorithm. Key elements of the algorithm included getting the inputs, correct logic within a selection control structure, control structure options (load and display) and appropriate indentation.

Question 10 (3 marks)

Each park ranger will be asked to provide a password for the monitoring program.
This password must contain more than four characters that are only letters or numbers. The following algorithm is created to check this.
It uses a function Length(string) to give the length of a string and a function Midchar(string, position) to give the character that is in each position from the start.

Begin
    Get Password
    LengthPassword Length(Password)
    If LengthPassword > 4 Then
        Position 0
        ValidChar True
        Repeat
            Position Position + 1
            PasswordChar Midchar(Password, Position)
            If PasswordChar Not alphabetic And PasswordChar Not numeric then
                ValidChar False
            Endif
        Until Position = LengthPassword
        If ValidChar = False
            Display Message Password contains invalid characters
        Endif
    Else
            Display Message Password too short
    Endif
End

Complete the table below with three passwords that will test each of the different circumstances listed.

I mean - the code is completely useless! Why is it there?
We were told in the question what the password rules are, and the code merely implements the rules.
There were no hidden sneaky errors in the code that would reject a valid password, or accept an invalid one!

Students only had to create three passwords that followed the rules given at the start of the question. They needn't have read the code at all. Or they could have wasted their time as I did trying to work out what the "gotcha" was, because - hey! - that code had to be there for a reason, right? Apparently not.

And to think of the time I wasted neatly formatting that pointless lump of code with all of those nice   and bolded operators and graphic assignment operators! Grrr.

This was far, far too simple, even it's only worth 3 marks!
And a time-waster for the better kids who carefully studied the code, suspecting it must have had some meaning.

Average mark: 2.6/3 (87%)

A number of students missed the requirement for >4 (greater than four characters) and only provided four, while others missed the requirement that to test the last condition the test data had to be greater than four plus an invalid character.

Question 11 (6 marks)

George talks to Melanie, who points out a major flaw in his password system. The aim is to have one tablet per monitoring station, not one per user, to reduce costs. A file of all usernames and passwords (expected to exceed 1000 over time as staff move between parks) will be on this tablet. Maximum memory will be needed on the tablet to display the high-resolution video, so Melanie suggests that the file is searched each time a user logs in instead of reading the whole file into memory. She suggests that the file be a random access file, and that the username and password are located using a binary search.

a. To allow a successful binary search on username to occur, describe what must be done with the records in the file before the search begins. 1 mark [3 lines]

They must be sorted by username.

Average mark: 0.2/1 (20%)

The data in an array needs to be sorted on the username field.
Students are encouraged to make use of past examination reports as there has been a question on binary searching on the past two examinations. This may have assisted students in avoiding the common mistake of not identifying the data field that needed to be sorted. Many students were aware that for a binary search to occur the data in an array needed to be sorted; however, very few indicated that it needed to be sorted on the username field.

b. Describe the process that the binary search will use to locate the given username. 2 marks [8 lines]

It will divide the list in half and determine which half the username should be in.
It discards the other half of the list.
It repeats the process until only one username remains, or none remain, indicating that the name is not in the list.

Average mark: 0.7/2 (35%)

The starting point of the search is the midpoint of the file. Half will be disregarded based on the midpoint being higher or lower than the search value. This is then repeated until the value was located.
Describing a binary search process was quite difficult for most students.
The following is an example of a high-scoring student response.

The binary search will compare the username in the middle of the file to username entered. If the entered username is greater then it compares it with the value in the middle of the usernames between the middle of the list and the end of the list. If the entered username is smaller than it will compare it with the username in the middle of the usernames from the start to the middle of the list. This is repeated until the middle value equals the entered username.

c. Explain the difference in the way records are accessed when using a random access file compared to a serial access file and why Melanie has suggested using a random access file. 3 marks [7 lines]

Since all records in a random file are the same length, the starting byte of any record can be calculated mathematically with (recordnum - 1) * recordlen + 1. Thus, any record can be accessed immediately, skipping any records between the search start point and the record's location.

Serial files, however, contain records of variable length so any record's starting point cannot be calculated. A search for a record must begin at the start of the file and step sequentially through every record until the desired one is found.

Thus, random file access can be far faster than serial file access, particularly as file sizes increase, which is what Melanie is anticipating.

There must be some other questions that VCAA can ask about binary searches and random files... These old chestnuts appear on every exam....

Average mark: 1.4/3 (47%)

To gain full marks students were required to describe how records are accessed when using a random access and a serial access file, and why random access files are more appropriate when doing a binary search.
Many students answered the first two parts of the question but many did not answer the ‘why’ part. Students are reminded that using the words ‘more efficient’ is not considered a justification. Students often find it difficult to clearly express the difference between random access and serial access.
The following is an example of a high-scoring student response.

Random access file allows access to any point in the file, meaning that it does not have to be read in the order it was written (usually indexed). Serial files only allow reading of the contents in the order it was written. Melanie wants to access the file of usernames/passwords for any random person, checking the input of a username and password hence a random access file will be more beneficial as it doesn’t have to read in order every time (like a serial file).

Question 12 (2 marks)

Brenda suggests to George that instead of using tablets to display the data coming from the drone, they should use mobile phones as these are cheaper and everyone has one, so tablets would not have to be purchased.
Explain why the tablet is a better choice. [6 lines]

• Its display is larger and easier to read.
• It has more space for a bigger battery, therefore having longer life between recharges.
  
• The software writers would not have to port the software to many different phone platforms. It could be tailor-made for a specific tablet, and exploit the advantages of that tablet.

Average mark: 1.3/2 (65%)

The use of a tablet was a better choice as the data being displayed was images with small detail; this was not appropriate on the small screen of a mobile phone.

Question 13 (4 marks)

When the drone lands, the data files, including video and GPS coordinates, will be downloaded onto a notebook computer. The files will then be deleted from the drone so that there is space for data files from the next flight.

a. Is this an example of backup or archiving? Give a reason for your answer. 2 marks [5 lines]

It's archiving. A backup leaves the copied data in place. Archiving moves the data, then deletes the original.

Average mark: 1.7/2 (85%)

This is an example of archiving, and many students were able to identify that this was characterised by removing the file from the original device.

b. Describe another procedure that would reduce the chance of these files being lost. 2 marks [7 lines]

"Another" procedure? The first procedure was not aimed at reducing the chance of files being lost - it was just moving them! The question should have been "Describe a procedure..."

So - what is the question expecting - backup suggestions, perhaps?

Copy the files to another device (e.g. USB drive, portable HDD, cloud storage) and store the files in a different location.

Note - Encryption would not stop the files getting lost. It would just stop them being read if they got stolen.

Average mark: 1.3/2 (65%)

Students were able to describe a backup method that used an additional storage medium, with many suggesting ‘cloud’ options.

Question 14 (6 marks)

A major security concern for the software being designed to run on the drone is that hackers (unauthorised users) could take over control of the drone.
State two measures that could prevent this from happening. Clearly explain how each would prevent unauthorised access to the drone.

The exam should have bolded the word "two".

• Encrypt all communications between the drone and its operators - this would obfuscate commands and data passing between authorised operators and the drone so that unauthorised users would not be able to read the data or send commands to the drone.
• Require a valid username and password for drone launchers and operators - this would prevent hackers stealing and launching a drone, or using a found/stolen tablet to control the drone.
• Keep inactive drones securely locked away from the public so hackers can't gain access to them and interfere with their operating software.
• Turn off the drone's SSID broadcasting. This would make it a tiny bit harder for hackers to detect the drone's wifi router.
• Make sure the drone's wifi router had a changed admin username and password. This would prevent hackers using default logins to access the drone's router and gaining access to its file system.
• Turn on strong wifi encryption (e.g. WPA2+). This encrypts local wifi communications between the drone's router and nearby people.
• Encrypt the stored source code of the drone's software so it cannot be read by hackers if they managed to find and copy it. This would prevent them finding security vulnerabilities and creating exploits to take advantage of them.
• Kill all of the programmers once the job is done. Bwahahahahaha! Now let those hackers try to nail the programmers to a stake and threaten to slice off their ... oops. Sorry. Got a bit "Game of Thrones" there.

Average mark: 1.8/6 (30%)

This question was poorly answered by most students. Many gave generic security measures, and/or failed to explain the measure or provide details as to how the measure would prevent unauthorised access. Students needed to ensure that the measures they were explaining were appropriate to the device identified in the question (the drone).
The following is an example of a high-scoring student response.

Install a firewall between the tablet and router
- A firewall controls which user can and cannot have access to certain ports.
- The firewall would only allow the park rangers access to the drones and would prevent unauthorised outside users.

Ensure all path instructions are encrypted
- Encryption changes the ‘plain text’ of the flight instructions into unreadable ‘ciphertext’.
- This will ensure that the drones can only accept instructions from the official tablet devices and nothing else.

Question 15 (3 marks)

Once the software has been accepted by PNPW, all park rangers will be required to use it. The park rangers are very unhappy about this as they have no idea how the new software will work and so they complain to the PNPW management.
Explain how management could resolve this conflict. [6 lines]

• They need to advertise the benefits of the software so rangers will appreciate its importance and be willing to give it a fair go.
• They then need to train rangers how to use the system in a brief and unthreatening way (with nice sandwiches.) Regional training sessions with small groups might be best.
• Training one ranger in each park to become a trainer would provide quick on-site support to other rangers by someone they are familiar and comfortable with.
• They also need to provide plenty of easily accessed documentation to teach or remind rangers how to use the system.
• They need to provide friendly technical support for rangers who are having system faults or trouble using the system.

Average mark: 1.7/3 (57%)

As this question asked students to ‘resolve this conflict’ it was expected that they would write about decision support frameworks; however, most responses included details of training and/or documentation and were awarded some marks. As some resolution was required, it was important to include some evaluation/feedback mechanism from the park rangers, before, during and/or after training.

END OF QUESTION AND ANSWER BOOK

On the whole - good, with a glitch or two. Certainly better than the ITA paper - as usual.

• Please don't include information or code that serves no purpose - e.g. B2 and C10. Good students will waste their time trying to find the typical logic holes in it, only to discover they could have been using their time ignoring it and getting on with answering questions!
• Don't re-examine the same material. Once is quite enough for AND and IF statements (C7 and C9).
  This also <<Includes>> B6a and B6b
• Proofread until it hurts - e.g. myPi.
• If you're going to use bold to highlight the required number of items, please do it consistently (C1 and C14)