ICT Unit 3 Revision 2021

PNG

(Portable Network Graphics) a raster graphics file format that supports lossless data compression. It can have 256 colours like GIF but you can also have 32bit PNG files for full colour. Supports transparency. Bitmap Best use = logos, icons and other images where a transparent background is preferred.

Describe a Bus Topology

- Each computer is connected to a single cable - Data can travel in both directions along this cable like a bus route - Easy to set up and it's very simple to add more computers - If the central cable fails, none of the computers will work

Disadvantages of Multimedia

- It can be expensive to buy the required hardware like graphics cards. This means not everyone can afford to use multimedia. - Multimedia often requires a high-speed broadband Internet connection when going online. - Multimedia often requires a lot of storage for video, music, animation and games. Games can take up over 50GB of space.

Advantages of Multimedia

- Multimedia has interesting ways of presenting information, e.g. sound/video. - Multimedia uses features like hyperlinking to provide an interactive, not passive, experience where the user takes control. - It is a more engaging way for children to learn (e.g. animations/quizzes).

describe star topology?

-all devices are connected to centre -all devices connected to central switch or server that controls the network -central switch allows many devices to access the server simultaneously -can be wired or wireless

describe a LAN?

-covers small geographical area located on a single site -all hardware owned by organisation that uses it -can be wired or wireless -buisinesses, schools and universities use them -homes have a lan connected to various devices

What do firewalls do?

-examine all data entering and leaving a network and block any potential threats -companies use firewalls to prevent unauthorised access

what does HTTP stand for and what is it used for

-hyper text transfer protocol -used by web browsers to access websites and communicate with web servers

describe a WAN

-network that connects LANs -connects LANs in different geographical locations -organisations hire infrastructure because WAN is much more expensive to set up than LAN -connected using telephone lines, satellite links or radio links -internet is one big WAN

Four Network topologies?

-star -bus -ring -mesh

Router

-transmit data between different networks -most commonly used to connect to Internet

Switches

-used to connect devices on a LAN

Pixelated

A bitmap image where it has become grainy, especially when enlarged, where you can see the individual dots of color

What is a client/server network?

A centrally administered server (or servers) that manage shared resources for multiple clients. The server has greater authority than the clients (typically desktop or laptop workstations).

Sensor

A device that responds to a physical stimulus (as heat, light, sound, pressure, magnetism, or a particular motion) and transmits a resulting impulse (as for measurement or operating a control).

Actuator

A device to produce physical movement based on output from a computer system.

Internet

A global network connecting millions of computers, making it possible to exchange information.

WAV

A high quality sound used for recording voices. + Very high quality sound. - WAV files are very large - not suitable for downloading.

Hotspot

A hyperlink on an object such as a picture.

Creative Commons

A kind of copyright that makes it easier for people to copy, share, and build on your creative work, as long as they give you credit for it.

check digit

A one-digit character found on bar codes used to check that the data entered is valid.

File compression

A process that reduces a file's size for storage or transmission purposes.

Protocol

A protocol is a standard for sending and receiving data.

Data Validation

A rule or check that is used to make sure data is sensible.

Visual check

A verification check where The user checks the data visually

ADC

Analogue to Digital converter: takes analogue sound data and converts it to digital data that can be processed and stored on a computer. Computers only understand digital format and sound waves are analogue.

Data logging

Automatic recording of data using sensors.

VUI disadvantages

Background noise interferes with speech recognition • User when they have a speech impediment, sore throat, cold or a strong accent will not be understood • Users with a disability that prevents speech would need to find a different method for input • Difficult to keep data input private as people can hear what you are saying • Words that sound the same, such as 'too' and 'two' may not be recognised

Bookmarks

Bookmarks are a list of favourite websites which we use most often.

Verification

Checking data is copied correctly by entering the data twice or comparing to another copy.

Field Length check

Checks to make sure a field is a specified length. E.g. password has a minimum of 8 characters

CLI

Command Line Interface

Methods to optimise images

Compress image / reduce file size Reduce the number of colours Reducing the detail / pixel density of the image Reducing the resolution (72dpi) Reduce the physical dimensions of the image

Analogue data

Continuous data which can have a range of values. Computers need to convert this data into digital form.

Multimedia

Different types of media including text, video, sound, graphics and animations.

DPI

Dots per inch: A measurement of the resolution of a digital photo or digital device, including digital cameras and printers. The higher the number, the greater the resolution. Screen image 72dpi Print images 300dpi

Double keying

Enter data twice to check for a match. e.g. new passwords

Transposition errors

Error that occurs when digits are accidentally swapped around Input : Gergory Instead of : Gregory

Biometric Disadvantages

Expensive scanners Privacy issues / misuse (DPA) Dirt causes problems Hygiene issues Dirty fingers etc may confuse the interface

Teleworking

Many people are working from home and using ICT methods to communicated with their place of business or clients. This is called teleworking, and involves the use of email, the internet and fax machines.

Copyright law allows you to make copies to give to a friend (True or False)

False

Copyright law allows you to make copies to sell to a friend (True or False)

False

Compression Advantages

Files load more quickly and the download time is less. You can store more files because the file size is smaller.

GUI

Graphical User Interface

GIF

Graphics Interchange Format. Can be used to create graphics and small, basic web animations. GIF uses fewer colours than JPEG or BMP, so these are not suitable for photographs. Their small size, however, makes them ideal for Internet use. Supports Transparency. Bitmap Best use = simple web graphics such as web buttons, charts and icons.

Vector Graphics

Graphics that use points, lines, curves, and shapes based on mathematical equations to represent images. They do not lose quality when zoomed or resized. Vector graphic file sizes are smaller than bitmaps

Storage Devices

HDD (Hard Disk Drive) SSD (Solid State Drive) External HDD/SSD Memory Stick Memory cards SDHC, SDXC, microSD Cloud storage

what does HTTPS stand for and what is it used for

HTTP secure -a more secure version of HTTP -encrypts all information sent and recieved

Greenhouses sensors

Heat sensors can tell actuators to open a window if it becomes too hot or turn on a heater if it is too cold. Humidity sensors could also be used to control sprinklers.

Digital Camera/Video Features

High number of mega pixels RAW format unprocessed JPEG compressed takes less space Anti-Shake Zoom Burst Mode Macro Mode Autofocus Auto Exposure Face Recognition

HCI

Human Computer Interface

HTML

HyperText Markup Language is the code used to make websites. It tells web browsers how and where to display the different parts of a web page. If browsers only displayed this code, websites would look a lot more complicated!

Social impact of ICT

ICT is making it easier to monitor what people are doing. a.) CCTV cameras are everywhere in towns and cities. b.) communication from phone calls, emails and text messaging can be monitored. c.) Satellites with cameras are capable of seeing what you are reading or identify a car number plate. d.) We can be tracked by mobile phone signals or our use of debit and credit cards.

Image compression

Images can be compressed using file type, resolution, dimensions, bit depth. JPG - algorithm - lossy PNG/GIF - Number of colours - lossless

Compression Disadvantage

Images, movies and sounds are of a lower quality. It can be expensive to buy the very best compression software.

Describe a mesh topology

In a mesh network topology there is no central connection point. Instead, each node is connected to at least one other node and usually to more than one. Each node is capable of sending messages to and receiving messages from other nodes. The nodes act as relays, passing on a message towards its final destination.

GUI Advantages

Intuitive Easy to Navigate No complicated commands Exchange data between apps (copy/paste)

Copyright, Designs and Patents Act 1988

It is illegal to share copyrighted material (art, photos, music, movies etc) without the copyright holder's permission.

what is a LAN?

Local Area Network

Input devices in Banking

MICR for Cheques Scanner for cards/NFC Touch screen Key pads (Cashpoints) Keyboard Mouse

audio compression techniques

MP3, OGG, M4A

Multimedia in Education

Many eLearning packages have been created which enable students to log in and view animations or video to help explain theory and concepts.

Template

Master pages enable you to create a basic outline of how each page on your site will look. All new pages can then use this template to create a consistent structure.

Output Devices

Monitor HiRes Printer Plotter Speakers

JPEG (JPG)

Most common graphic file format, full color graphic format (16.7 million colors), relatively small file size. This file type compresses images, which makes their file sizes smaller. This is ideal for uploading/downloading, but this reduces image quality. It has NO transparency. Bitmap Best use = rectangle or square photos and photographs on your website.

security system sensors

Motion sensors can detect movement. Heat sensors can be used to detect human body heat.

Input Devices

Mouse Touchpad Graphics Tablet Touch Screen (Input and Output) Microphone Motion-sensing input devices (Games) Motion capture sensors Games controllers Cameras Webcams Scanners jog/shuttle wheel video controller Microphone (crucial for video)

Gesture Disadvantages

Not always accurate Difficult to enter text • It is difficult to select small items

Optimisation

Optimisation balances the compression of a file with the output quality. If a file is compressed too much the quality will be reduced so that videos and pictures become fuzzy.

TIFF

Tagged Image File Format, uncompressed image file format. Very good image quality but larger file size. Bitmap. Best use = images and photographs for high quality print.

Menu Interface

Programs whose user interface employs menus, an example would be an IPod or an ATM"

Advantages of Data logging

Respond very quickly to change Run 24 hours a day Operate in dangers conditions Accurate measurements Data can be processed quickly Can be timed to start at different periods Share data easily Remote access to sensors

Pixel

Short for "picture element" it is the fundamental unit of a digital image, typically a tiny square or dot which contains a single point of color of a larger image.

Traffic control sensors

Some traffic lights use traffic detection loops. In other words, they can detect when a car goes over that part of the road and can turn green.

BMP

Stands for BitMaP. Saves the image as a group of pixels. Used in drawings in programs like Paint. This creates a good quality image, but file sizes can be very large which increases upload/download times. Not commonly used today.

Stock control

Stock control is the overall management of stock levels. When an item is sold: • Stock level reduced by 1 • Stock level checked against re-order level • If below re-order level automatically re-orders. • Stock totals updated when new stock arrives on shelf.

Stock level

Stock level is the quantity of a particular item in the shop or warehouse.

Point of Sale (PoS)

The checkout tills in large stores and supermarkets are usually linked to a computer that monitors the sale of items. The till is often called a PoS.

Touch interface

The primary user interface on modern mobile devices where keys are replaced with tactile interaction.

touch interface

The primary user interface on modern mobile devices where keys are replaced with tactile interaction. Also used in self service checkouts and learning aids

Gateway

These allow two different networks to speak to one another by translating data. e.g. Connect a LAN to a WAN

Bridge

These are used to join - or bridge - two LANs together with the same protocols to form one larger network.

Car park sensors

These use cameras, npr(number plate readers), actuators(switches) for barriers and ticket scanners to control access to the car park.

Copyright law restrict you from making modification (True or False)

True

RAW

Uncompressed Camera file format

URL

Uniform Resource Locator

Biometric Advantages

Unique Cannot forget or lose it like a card No-one else can register for you Real time registration Difficult to forge Cannot be shared Reduce administration costs

Bitmap Graphics

Use square pixels arranged in a grid that have assigned colours. They lose clarity when viewed up close or zoomed in, also referred to as raster graphics

Automatic door sensors

Uses PIR to detect movement and an actuator open doors when someone comes near. A pressure sensor is used to make sure a person does not get trapped in closing doors.

Biometrics

Uses unique parts of the body to control a computer. You can log in to a computer using a retinal (eye) or finger print scan. Computers can catch criminals by looking at the way they walk or at their DNA print.

Biometric interface

Using Thumb, hand, Face, Retina recognition to interact with a computer

Invalid character check

Validation rule to make sure that the correct characters are used in a field

Format check

Validation rule to make sure the data follows the correct format e.g. Post Code.

range check

Validation technique. Ensures a field is between a certain range of values.

Spell Check

Verification check the spelling of a document by comparing to a dictionary on the computer.

Describe a ring topology?

Where data passes through each node, carried in data units called tokens. Traffic is one way which prevents collisions.

what is a WAN?

Wide Area Network

Gesture interface

Wii, Kinect using gestures interact.

WIMP

Windows, Icons, Menus, Pointers

Menu Interface

With menus, you have to select a choice from a list of different menu options. Dialogue boxes can also pop up on the screen to ask the user a question or inform them about something, e.g. when an error occurs with an application.

Voice User Interface (VUI)

You can give the computer verbal commands by speaking into a microphone. Used in some GUI operating systems which come with voice recognition software.

GUI disadvantages

You need more memory RAM Need more storage HDD/SSD Relatively processor intensive Computer experts who know advanced commands may find GUIs slower than command line interfaces.

Command Line Interface

You need to remember and type in certain commands to operate. Computers normally allow you to use command line features when deleting all data from a PC and installing a new operating system.

Control Systems

a computer or microprocessor which uses a program to handle data from sensors to output control signal to operate an object or system.

Extranet

a private, corporate computer network that links company departments, employees, and databases to suppliers, customers, and others outside the organization

Economic impact of ICT

a.) expanded markets b.) allowed companies to streamline their operations so they can employ fewer people c.) decreased their expenses d.) maximized profits

Fair Use

allow the lawful use or reproduction of work without having to seek permission from the copyright owner(s) or creator(s) or infringing their interest under specific circumstances.

Intranet

an Internet-based network used within the boundaries of an organization. It is a private network that may or may not be connected to the public Internet.

What is a peer-to-peer network?

any network without a central file server and in which all computers in the network have access to the public files located on all other workstations

MP3

compresses music so is used for downloading Internet music tracks. + Most well-known format for downloading music. + Files are compressed to make them smaller - faster downloads. - Quality is lower when compared to WAV.

Hyperlinks

connect one web document to another or connect one web page to other web pages, files, videos, ..

Lossless Compression

data compression techniques in which no data is lost.

Lossy Compression

data compression techniques in which some amount of data is lost. This technique attempts to eliminate redundant information.

Transcription errors

data entry errors that occur when a user is entering data from a printed document or from verbal instructions

Sound editors

enable you to change sound waves by adding effects such as echo, increasing loudness or changing pitch. This software has been in the news very recently when it was revealed that The X Factor uses the auto-tuning feature on contestants.

MIDI (Musical Instrument Digital Interface)

format for recording music from synthesizers and other electronic instruments

Keyword Searches

look for websites that contain a specific word or phrase

navigation bar

menu bar of a web site

Audio Compression

reduces the size of a sound file by removing bits that represent extraneous noise and sounds that are beyond the frequencies of normal hearing

WMA

windows media audio; compressed audio format originally designed for Windows Media Player + Compresses files to make them smaller - enables many files to be stored and downloads are quicker. - Not as popular and widely used for music as MP3 files.

Menu Disadvantage

• Irritating if there are too many menu screens to work through - users get annoyed or bored if it takes too long • Navigating can be a long process • Can get "lost" in the navigation

multimedia interactive components

• Keyword searches • Quizzes • Automatic marking/feedback • Questionnaire • Games • Links • Animation/Video controls • Interactive Galleries

Menu Advantages

• No need to learn a lot of commands • Intuitive/easy to understand • Easy to navigate • Ideal for beginners - everything is in a logical place/order • No need of expert language to learn • Little processing power needed

Banking

• Paying bills • ATMs - obtaining cash • Card services - Credit / Debit / Smart cards • Online banking o view statements / check balance o transfer money between accounts o make payments o apply for loans o open account • Key encryption for remote banking / Two factor authentication • Bank app to manage accounts • Obtaining rewards • Scanning cheques in at pay-in point

CLI Advantages

• Quicker to type commands • Quicker to input commands as shortcut keys can be used • Little memory and processing power needed compared with other interfaces • Little storage space is required (no graphical images to store) • Experts who have memorised the comterm-278mands find it very fast to use

Touch interface disadvantages

• Screen can be easily damaged/scratched • Dirty screens are difficult to read • Users must be within arm's reach of the display • It is difficult to select small items • User's hand may obscure the screen • Screens need to be installed at a lower position and tilted to reduce arm fatigue • Some reduction in image brightness may occur

VUI advantages

• Speech input is much faster than keyboard input • No need to learn to type • Less danger of RSI • Reduces typing mistakes such as spelling/hitting wrong key • Keyboard takes up room on the desk • Users with a disability that prevents typing can use speech input • Hands-free advantages - can multitask • Users find talking more

methods of payment

• Store cards • Vouchers/coupons • Mobile phone/ NFC • Loyalty card points • Gift cards

CLI Disadvantages

• Very confusing for someone who has never used a command line interface • Commands have to be typed precisely. If there is a spelling error the command will fail • A large number of commands need to be learned • Instructions cannot be guessed • Not suitable for a novice

Gesture Advantages

• Very intuitive • Easier to use as the user simply gestures for what they want to happen. • No need to touch anything/could be used in a sterile environment. • Manage multiple points of an input in one go.

Touch interface advantages

• Very intuitive • Easier to use as the user simply touches what is seen on the display • No keyboard or mouse is required • Touching a visual display of choices requires little thinking and is a form of direct manipulation that is easy to learn • Easier hand-eye coordination than mice or keyboards

Teleworking disadvantages

• less social interaction and teleworkers may feel isolated. • Need to be able to trust employees • Harder to monitor workers • Technical difficulties • Distractions at home

Teleworking advantages

• no travel issues • no time wasted in travelling to work • flexible hours better for staff working conditions • employers don't have to provide office space or facilities. • Staff take fewer sick days • Staff may be more productive at home • Employers not restricted to the local workforce

Environmental impact of ICT

• use recycled paper or store documents on a hard drive rather than using paper and so save the forest resources. • Reduces carbon footprint - businesses use video conferencing rather than sending delegates to meeting. • The increase in delivery lorries on the road has caused increased congestion and increases in carbon emissions • ICT is supposed to lead to a paperless society but more and more paper seems to be consumed affecting rainforests and influencing global warming. • Use of smart technology to control our living environment • Old ICT equipment needs to be disposed of correctly which is expensive. Dumping old computers etc on landfill sites can cause pollution of toxic substances into the water supply and lead to health problems • ICT equipment generates heat so many organisations install air conditioning systems leading to increased carbon emissions • Many computers are left on standby, wasting electricity unnecessarily and increasing carbon emissions.