Cambridge A Level Applied Information and Communication Technology 9713 — 2017 Oct/Nov Paper 3 · Variant 2

1 Describe, with suitable examples, what is meant by a climate model. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[4]

Mark scheme: Question Answer Marks 1 Four from: 4 Max three from: Describes the behaviour of factors affecting Earth systems Using mathematical/differential equation models Earth/planet divided into 3D grid Appropriate example of type of model e.g. convective-radiative/ box/radiant heat transfer Max two examples from climate drivers: Atmospheric measurements used Oceans/seas temperature/flow/mass measured Ice masses measured in terms of mass/flow/movement/ temperature Land surfaces/land use for agriculture/(de)forestation Rainfall measurements/rising water levels/water tables Energy/electromagnetic radiation/heat/infrared/visible light from the sun Living organisms/ecosystems distribution on land/in water Cloud cover/type over land/sea areas.

2 Describe, with suitable examples, how physical variables would be collected automatically for use in the computer climate model. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[4]

Mark scheme: 2 Four from e.g.: 4 Use of sensors connected to a data logging/computer system Via an ADC because computers cannot read analogue data Manual data collection by humans/data entry into computer system Temperature sensor to measure ambient/change in temperature Visible light sensor to measure (visible light) levels/intensity Infra-red sensor to measure radiant heat falling on surface/infrared light levels Humidity/moisture sensor to measure amount of water/moisture levels Water level sensor to measure height of sea/sea level/river level Sound sensor to measure seismic movements Airflow sensor/anemometer to measure airflow speeds/quantity CO2 sensor to measure increase in CO2 levels in atmosphere/water.

3 Explain how a climate model could be tested to find out if it can produce reliable predictions. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[4]

Mark scheme: 3 Four from: 4 Start from a point in the past (e.g. 40 years ago)/using archive data Enter the data about the physical variables at that time Run the model to cover the time period up to present Compare the results/predictions from the model against what actually happened Repeat the process for different time periods Evaluate the predictions of the model.

4 Explain why climate models are not suitable for weather forecasting. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[2] Scenario 2 Questions 5, 6, 7 and 8 A global marketing company stores its documents and customer data in computer files that are used in its offices around the world. Staff can use the files to create personalised letters for sending to customers. The letters are created from master documents and use customer data files. The master documents, and other company documents, are stored as rtf files and the source files are extracted from the customer data files and stored as csv files. The csv files are also used to exchange customer data between the different software applications used in the offices.

Mark scheme: 4 Two from: 2 Climate models only predict trends in weather patterns Averaged out over long periods of time measured in years Climate models and weather forecasts use different physicals variables Cannot predict specific values e.g. temperature at a particular point in time/time of day.

5 Describe how data is stored in a csv file. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[2]

Mark scheme: 5 Two from: 2 Numbers and text are stored as plain text/ASCII characters Arranged in a tabular format Each line of the table is a data record... ...with the same format Each field in the line/record is separated/delimited by a comma Each record/line ends in a carriage return/CR character.

6 Explain why csv files are used to exchange data between different software applications. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[2]

Mark scheme: 6 Two from: 2 Many software applications can import/export csv files/can support RFC 4180 file formats Most applications use their own proprietary format Proprietary format which cannot be used by other applications because of licencing/copyright issues.

7 Explain, with suitable examples, how the use of csv files can cause problems when exchanging data. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[3]

Mark scheme: 7 Three from e.g.: 3 Data in fields may contain a comma so parsing may be inaccurate/fields may not import correctly CSV files may use ‘tabs’ or ‘spaces’ or ‘semi-colons’ as delimiters even though the file format/extension says CSV Quotation marks may be required to enclose fields that contain commas but the fields may also contain embedded quotes CSV file format is not standardised (so files can contain alternative delimiters)... ...making parsing of the files inconsistent/difficult by applications.

8 Discuss the benefits and drawbacks of using the rtf file format to store documents. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[8] Scenario 3 Questions 9, 10, 11 and 12 A company with offices in cities all over the world uses dedicated cables as well as wireless technology to connect its office computers and other devices to its networks. The networks have servers to provide IT services and data storage for the company staff. The networks are connected to the internet. The company uses a variety of methods to try and protect the computers, devices and the data stored on the networked servers from viruses and from attacks by malicious sources.

Mark scheme: 8 Eight from: 8 Benefits: Contains formatting instructions Is readable by humans if loaded into basic text editor Formatting codes are self-explanatory Plain text/ASCII characters in document are readable Can be used in a variety of word-processing applications No need for same application as originator Drawbacks: Use of extensive formatting can make document difficult to read File size is larger than plain text file Non-ASCII characters/slashes/dashes/quote marks must be specially encoded/‘escaped’/used with control characters to change meaning of subsequent characters Non-Latin scripts/Chinese characters are not legible in RTF files Need to be converted from 7-bit RTF structure to 8-bit structure in some operating systems/Windows OS/Apple OS. Max 6 for all benefits or all drawbacks. 1 mark available for a reasoned conclusion.

9 Describe the limitations of using wireless access points to connect computers to a cabled network. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 9 Six from e.g.: 6 Effective connection distance is limited Obstacles in between WAP and device can further reduce connectivity Affected by positioning of WAP/height above ground/type of antenna in use Presence of other wireless devices/mobile (cell) phones transmitting on same/close frequencies Weather conditions affect the transmission of wireless signals Power output of device affects useable distance from WAP Lower bandwidth available compared to wired connections... ...wireless max 350Mbits/s but typically only 25Mbits/s c.f. wired at 1000Mbit/s Security based on encryption which adds an overhead to TCP/IP packets/processing Unsecured WAP allows access to anyone within range.

10 Describe how a system could be set up so that staff could securely access servers in the different offices around the world. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 10 Six from: 6 Use of virtual private networks (VPNs) Use of secure socket layer (SSL) protocol Use of encryption for traffic to/from networks to other networks VPN gateway set up as integrated firewall, anti-malware and intrusion detection system... VPN gateway to gateway connections create permanent links between office networks over internet... ...creates VPN tunnels over public telecommunication systems Use of network access control (NAC) so that all computers/devices meet company standards e.g. anti-malware, updates, configuration Use of network address translation (NAT) to ‘hide’ local IPs addresses.

11 Viruses are a type of malware that can threaten the security of computer data. Describe, with examples, different ways, other than malware, that an attack from a malicious source could threaten the security of the company data. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[5]

Mark scheme: 11 Ways from e.g., max three per way: 5 Interception of data during its movement around/through the network... ...which is a passive attack using... ...e.g. port scanner software/packet sniffer software to capture/read packets Active attack using commands« ...to change the behaviour of the network from its normal behaviour ...designed to alter/delete network resources Social engineering attack/pretending to be e.g. IT technician/staff member... ....to manipulate other employees ....to perform actions that potentially cause damage to company resources Phishing attack using social engineering techniques to steal confidential information by sending bogus emails sent to employees... ...to direct them to malware infected websites/divulge confidential information.

12 Describe how the spreading of viruses between the networked devices could be prevented. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[4] Scenario 4 Questions 13, 14 and 15 A theatre company puts on performances of a play twice a day on every day of the week. Customers can book tickets for the performances using the theatre’s automated booking system. The automated booking system uses a database to store the bookings. To avoid customer disappointment, the database is designed to prevent double-bookings of the seats in the theatre.

Mark scheme: 12 Four from e.g. : 4 Use of anti-virus software to scan incoming/outgoing email messages/attachments/files Regularly scan existing files for viruses/changes to file Restriction of software installation to authorised personnel Restrict the use of external storage devices by staff/users Restriction of connection to network of computer devices to only authorised devices Use of firewalls to prevent unauthorised data packets from entering the network from the internet/outside.

13 Describe the features of an automatic system that enable customers to manage the booking of theatre seats. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 13 Six from: 6 Allow customers to choose/select the time/date of performance Allow customers to choose/select the number of persons/adults/children tickets Allow customers to check the availability/position of seats Allow customers to select/check the price/price range of the different seats available Allow customers to reserve/book the seats/tickets at that price Automatically create/produce/issue (e)tickets for sending/posting/ emailing/make available for download/collection at automatic tellers Enable the verification /processing of payment for tickets Send confirmation emails to online customers Allow customers to make changes to the reservations/booking.

14 Discuss the advantages and disadvantages to customers of using automatic booking systems to book theatre seats. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[8]

Mark scheme: 14 Eight from: 8 Advantages: Bookings can be made at any time Seats can be reserved for a period of time e.g. 30 minutes while customer decides whether or not to go/have that seat Confirmation of the reservation/booking can be sent by mail/letter/SMS/ text message Customer can track tickets/have them sent by email/reserved at theatre/download at automatic teller at theatre so not lost/forgotten Disadvantages: Difficult to cancel after payment/reservation/booking has been made... ...loss of deposit/whole cost of the booking Customer can more easily make a mistake/reserve/book the wrong seats/time If the server is down/running very slowly/overwhelmed with customers trying to book, then bookings cannot be made... ....customer is dissatisfied/not sure if transaction is completed Payment verification/processing problems after the reservation/booking is made... ... reservation/booking may be cancelled/invalid Customer may have to wait for ticket to be sent by post... ...if booking close to the day of the event the tickets might not arrive in time. Max 6 for all advantages/disadvantages. One mark is available for a reasoned conclusion.

15 Explain how the database is set up to prevent the double-booking of seats in the theatre. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[4] Scenario 5 Questions 16 and 17 A government website allows citizens access to legal and other public interest information. The government has decided that the website should be redesigned to allow greater access by disabled people to the information shown on the web pages.

Mark scheme: 15 Four from: 4 When seat is booked seat is flagged/locked while booking process proceeds Include a field/flag for ‘booked’/equivalent... ...use Boolean data type indicating ‘available’ or ‘unavailable’/ ‘booked’ Flag field as ‘unavailable’/ ‘booked’ during period of time that customer is making booking/searching e.g. 10 minutes Flag field as ‘unavailable’/ ‘booked’ when reserved by/sold to customer.

16 Discuss the benefits and drawbacks of making legal information available on the government website. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 16 Six from: 6 Benefits: Legal information is freely available to all/anyone with internet access Can research/find links to background information Can follow research/links to more detailed information Can allow people to see/know about updates in regulations/laws Drawbacks: Information may be inaccurate/not up to date/incomplete... ...due to summarising/poor explanations/not be in the precise legal terms ...not be written by legal professionals ...may not quote case law Inexperienced people can come to regard themselves as ‘legal eagles’/experts. Max 4 for all advantages/disadvantages.

17 Explain how the government website should be designed to allow disabled people to access the information more easily. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 17 Six from: 6 Ensure that accessibility issues/local laws/regulations are addressed with reference to their visual/motor/auditory/cognitive disabilities ...with reference to the content of the site as to how it operates/ is perceived by the user Provision of text alternatives for any non-text content... ...to allow change into other forms e.g. such as large print/braille/speech/ symbols/simpler language Provision of alternatives for time-based media/video/audio media Content can be shown in different ways without losing of information/structure e.g. simple/less complex layouts of text/lists/data Content separates foreground from background to make it easier to see/perceive Colour vision deficiencies should be catered for when choosing text/background colours Viewers should have sufficient time/control over the time that data is on screen/control over automatic moving on of data/screens so that they can read/use content All functionality should be available from a keyboard Content/flashing text/colours must be avoided to avoid causing seizures Guidance should be provided for navigation/content location/determining location on the website All web pages on the website must appear/operate in predictable manner Operation of the website and the content must be readable and understandable... ... assistive technologies (e.g. text-to-speech or vice versa) must be able to make sense of/use the content/navigation controls.