Router PDF

0riday 5/7/2024 Router -Router are used to route data packets from one network to another network, based on IP address *Routing table - router - check IP address Look-up table - Switch/Bridge - MAC address -A router has its own IP address -Routers are used to join a LAN to the internet -When a...

0riday 5/7/2024 Router -Router are used to route data packets from one network to another network, based on IP address *Routing table - router - check IP address Look-up table - Switch/Bridge - MAC address -A router has its own IP address -Routers are used to join a LAN to the internet -When a data packet is received at one of its ports, the router inspect the IP address and determines whether the data packet is meant for its own network or for another, external network -If the data packet is meant for its own network,then the data packet is router to the local switch or hub. Otherwise, the data packet is transmitted to a different router and therefore to an external network. (external network(internet) - WAN(Wide Area Network)) (*If it is a switch broadcast to everyone, and if router look for others in the world) -The routing table will contain information about the router’s immediate network (such as computer addresses) and information about other routers in its immediate vicinity. -When a data packet reaches a router, it examines the IP address and it will be able to work out that data packet is intended for a computer on its own network. -The router does not need the MAC address because the data packet will be sent by the router to the switch on the recipient's local network. -The switch can then use it look-up table to send the data packet to the correct device. *MAC address is also known as a Physical Address  2 Router Bridge Connect various types of network together Connect LANs together Scans a device IP’s address Scans a device’s MAC address Data is sent out using data packets Data is sent put using data packets Connected networks will use different protocols Connects networks together that use the same protocol A routing table is used to direct data packets to the correct It uses a MAC address look-up table and receives data from device several points and links them to a single point of the network Has more than 2 ports Has only 2 ports Possible Question : 1) Why does a router has to inspect the IP address when a data packet is received at one of its ports? To determine whether the data packet is meant for its own network or for another, external network. If the data packet is meant for its own network, then the data packet is routed to the local switch or hub. Otherwise, the data packet is transmitted to a different router and therefore to an external network. 2) Why do routers don’t need MAC addresses when sending the data packet? It is because the data packet will be sent by the router to the switch on the recipient’s local network. The switch can then use its look-up table to send the data packet to the correct device. 3) Complete the table below : Router Bridge Connect various types of network together Connect LANs together Scans a device IP’s address Scans a device’s MAC address Data is sent out using data packets Data is sent put using data packets  3 Connected networks will use different protocols Connects networks together that use the same protocol A routing table is used to direct data packets to the It uses a MAC address look-up table and receives data correct device from several points and links them to a single point of the network Has more than 2 ports Has only 2 ports 5) Explain the term “Spread-spectrum frequency hopping” It is where devices constantly change channels that they are using to minimize the risks of the interference with other devices. 6) Which are the three common cloud storage systems? Public cloud, private cloud, and hybrid cloud Tuesday 7/9/2024 Wi-Fi and Bluetooth -Both offer wireless communication between devices. -They use electromagnetic radiation as the carrier(in the form) of data transmission. Bluetooth -Sends and receives radio waves in a band of 79 different frequencies (known as channels) -Devices using Bluetooth automatically detect and connect to each other devices because each communicating pair uses a different channel. (79 options) -Bluetooth uses 2.4 GHz (GigaHertz) -Spread-spectrum frequency hopping is where devices constantly change channels that they are using (several times a second) to minimize the risks of interference with other devices -Bluetooth is useful : -When transferring data between devices which are very close together (less than 30m distances) -Bluetooth connections typically become weaker or lost when the devices are more than 10 meters apart -When the speed of data transmission is not critical  4 -For low-bandwidth applications (e.g. when sending music files from a mobile phone to a headset) Wi-Fi -Sends and receives radio waves in several different frequency bands - 2.4GHz and 5GHz -The 5GHz band has a faster data transfer rates but a shorter signal range -Wi-Fi offers much faster data transfer rates, better signal range and better security than Bluetooth -A Wi-Fi enabled device can access the internet wirelessly at any access point (AP) or ‘hot spot’ up to 100m away Advantages 2.4 GHz 5 GHz Farther range Higher transfer speed Can penetrate solid objects Less vulnerable Disadvantages 2.4 GHz 5 GHz Vulnerable to interference Shorter range Slower speed Harder time penetrating solid objects Features Bluetooth Wi-Fi Transmission frequency used 2.4 GHz 2.4, 3.6, 5 GHz  5 Data transfer rate (max) 25 Mbits/seconds 250 Mbits/second Maximum effective range (m) 30 metres 100 metres (but can be obstructed by walls) Maximum number if devices Up to 7 Depends on the router used connected (about 250 devices) Types of data transmission Key matching encryption WEP (Wireless Equivalent security Privacy) and WPA (Wi-Fi Protected Access) Friday 12/7/2024 Cloud Computing (Storage) -It is a method of data storage where data is stored on remove servers -The same data is stored on more than one server of maintenance or repair, allowing clients to access data at any time. This is known as data redundancy (Necessary if one shut down or maintenance) -The physical environment of the cloud servers is owned and managed by a hosting company -3 common cloud storage systems : -Public cloud - computing services offered by third-party providers over the public Internet, making them available to anyone who wants to use or purchase them.(Allows anyone to see with the link) -Private cloud - computing services offered either over the internet or a private internal network and only to select users instead of the general public.(Only the maker and selected person can see it) -Hybrid cloud - is a computing environment that combines an on-premises datacenter (also called a private cloud) with a public cloud, allowing data and applications to be shared between them.(Both) Advantages of cloud computing(storage) : -Customer/Client files stored can be accessed at any time, from any devices, anywhere in the world, as long as internet access is available. -No need to carry external storage device. -Provides user with remote backup and recovery of data. -Cloud system offers almost unlimited storage capacity. (at a price) Disadvantages of cloud computing(storage) : -Security aspects of storing data in the cloud (e.g. storing important data in a public cloud) -Slow or unstable internet connection would cause problems accessing or downloading their data/files.  6 -Support for cloud storage isn't the best, especially if you are using a free version of a cloud provider. Network Types : -Local Area Network (LAN) (Minimum 3 devices connected will form LAN) -Wireless Local Area Network (WLAN) -Wide Area Network (WAN) *Extras -Metropolitan Area Network (MAN) -Personal Area Network (PAN) 1) Local Area Network (LAN) - Usually within one building or geographically near each other. - Computers and devices connected to hubs or switches. - One of the hub/switch will usually be connected to a router to allow the LAN to connect to external network, such as the internet. Advantages of networking using LAN : -They allow sharing of resources such as hardware (e.g. printers and scanners) and software (e.g. word processor and photo editing software) -They permit easy communication between users of the LAN -They use a security administrator that ensures security (e.g. the administrator can maintain passwords and also monitor data traffic within the network) / (giving permission) Disadvantages of network using LAN : - Easier spread of viruses throughout the whole network. - Queues for shared resources (such as a printer) can be frustrating. - Slower access to external network. - If the main server breaks down, the network will no longer function properly. 2) Wireless Local Area Network (WLAN) - Similar to LAN, but there is no wire or cable. - It provides wireless network communication over a short distance using radio or infrared signals. - Devices such as more access points (APs) need to be installed in order to permit uninterrupted wireless communication. Friday 19/7  7 Password Passwords are used : -When accessing your email account -When carrying out online banking -Accessing social networking sites How to protect passwords? Run anti-spyware software Change password on a regular basis Passwords should not be easy to crack Strong passwords should contain: -at least one capital letter -at least one numerical value -at least one other keyboard characters(such as @,*,& etc.) Other authentication method Zero login and biometrics, Magnetic stripe cards Smart cards Physical tokens Electronic tokens Tuesday 16/7/2024 Wired vs Wireless Activity/Category Wireless networking Wired networking Freedom of movement of users Users can access network from Users location is limited as there is a anywhere within the range. need to use cables/connect to a port. Sharing files Easier but transfer speed may be Less convenient as the devices need to slower. be cabled by transfer speed is faster. Cables No cable is involved. Need to install cables which can be messy if not managed properly. Business For businesses dealing with the Wired networks are not convenient for  8 public,customers like and often expect public use but acceptable in a wireless. (More convenient for traditional office. business) Connection speeds Slower than wired. Faster than wireless. Security Less secure than wired. Both More secure than wireless. bandwidth and information can sometimes be accessed. (As long as people have your password they can connect to your laptop) Set up Upgrading to a wireless network can Can also be difficult and expensive to be difficult and expensive. set up. Wide Area Networks (WANs) *-The following is used as a guide for deciding the ‘size’ of a network : (may come out in exam) -WAN : 100km to over 1000km -MAN : 1km to 100km -LAN : 10m to 1km Electronic Conferencing : -Video Conferencing -Web Conferencing -Audio Conferencing 1) Video Conferencing -It is a communication method that uses both video and sound -It carries out real time and make use of some form of network -The basic hardware includes : -Webcams -Large monitors/TV screens -Microphones -Speakers -A few items to consider when a conference is about to begin : -It is important to agree on the date and time for the conference to take place -Delegates (People who joined the owner) in each conference room must log into the video conferencing (VC) system -The VC set up needs to be checked before the meeting goes live  9 -Webcam placed in the correct position -Microphones need to be placed centrally so that all the delegates can speak -It is important for 1 person to be the main contact in each conference room to ensure that the delegates are heard Advantages of using video conferencing : - Convenient - Possible to hold conferences at a short notice - Able to connect to people who r from other countries - Not travelling physically to the meeting can reduce -Travelling cost -Accommodation or venue hire -Costs of taking people away from their work for days and yet still pay their wages (large ‘hidden’ ost) Disadvantages of using video conferencing : - Potential time lag in responses - Images can jerk due to poor connectivity - Can be a problem if the delegates live in different countries where the time zone differences are large - Training people to use the system can be costly and time consuming. - Can be demotivating to staff if they believe one of the interesting part of their job is international travel - A reliable network connection is important 2) Audio Conferencing - If refers to meetings held between people using audio (sound) equipment - It can be done over the standard telephone network - The equipment needed is just a standard telephone - It is possible to hold an audio conference using a computer, as long as a microphone and speakers are connected aka Voice over Internet Protocol (VoIP) - In the case of VoIP, the equipment needed includes : - Computer - External microphone / speakers -Broadband phone -Standard phone - VoIP allows communication using voice and instant messaging - The drawback of audio conferencing is the quality of the sound because it is totally reliant on a fast & stable broadband connection, otherwise ‘drop out’ (loss of voice on occasions), echoing or a very noisy line can happen, making it difficult to understand 3) Web Conferencing  10 - Often referred to as webinar or webcasts. It uses the internet to permit conferencing to take place - Multiple computers are used within this system, all connected over the internet. - Uses : -Business meetings to discuss new ideas -Presentations -Online education or training - Equipment needed : -Computer -Stable and high-speed internet connection - How to carry out web conferencing ? Ans : Download an application or log onto a website from a link supplied in an email from the conference organiser. Features of web conferencing : -Slide presentations and documents can be posted on the conference website in advance prior to the meeting -Host can share screen -’Whiteboard’ facility -There is a messaging features which allows delegates to send text messages throughout the conference Chapter 5 : The effects of using IT In this chapter you will learn about : Microprocessor-controlled devices (means a code that requires a machine to work) Health issues from using a computer Examples of Microprocessor-control devices -Rice cooker -Fridge -Air-conditioner -Alarm clock -Air fryer  11 -Monitor -Speaker Effects on using microprocessor-controlled devices in the home How does microprocessor-controlled devices in the home can have positive and negative effects on our : -Lifestyle -Leisure time (Free time) -Physical fitness -Data security -Social interaction We know that household devices are fitted with microprocessor to control a large number of their functions. Labour-saving devices (Group 1) -Explanation : These devices allow people to get on with other things while the device carries out their tasks. Other devices (Group 2) -Explanation : These devices are easy to use and give additional features, such as ‘intelligent tuning’ in television sets. Group 1 (At least 3) Labour-saving devices : -Washing machine -Microwave oven -Rice cooker -Smart fridge/freeze Group 2 Other devices : -Alarm clock -Television set -Mobile phones & tablets  12 Effects of microprocessor-controlled labour-saving devices on a person’s lifestyle, leisure time and physical fitness : Advantages Disadvantages -People no longer have to do manual task at home. -Labour-saving devices can cause people to become less fit as manual task wouldn't be required. -Gives people more time for leisure activities, hobbies, -People will become lazy. shopping and socialising. -Automated burglar alarms give people a sense of security as -There is a potential lose to household skills (e.g. iron a they give a very sophisticated level of intruder warning at shirt, bake a cake, set a table) all time. -Smart fridges and freezers can lead to more healthy -There is a risk of cybersecurity threats. lifestyle and prevent food waste. Ways in which all microprocessor-controlled devices can affect our lives and to improve its functionality. Advantages : 1) Microprocessor-controlled devices save energy because they are efficient and are able to switch themselves off after a period of inactivity. 2) It can be easier to ‘program’ these devices to carry out their tasks rather than turning knobs and pressing button manually. (e.g. QR codes on the side of food packaging can be simply scanned and the oven automatically sets the cooking program.) Disadvantages : 1) It is usually not cost effective to repair circuit boards once they fail ; the device is then usually just thrown away. 2) They can be more complex to operate for people who are technophobes or who are not very confident around electronics devices. 3) Leaving some devices on standby mode is very wasteful of electricity. (e.g. televisions or satellite receivers)  13 Monday 19/8/2024 Social Interactions Positive aspect of using a microprocessor-controlled devices : - Easier to make new friends using chat rooms. - Easier to find people who share similar interests/hobbies. - Less expensive to keep in touch using VoIP technology. Negative aspect using a microprocessor-controlled devices : - People do not meet face-to-face as much. (social isolation) - A lack of social interaction may cause people to be more anxious about meeting each other in real life. - People behave differently when interacting online. Sometimes acting ruder or more aggressive, and cyberbullying is a real problem, particularly among young people. Monitoring and controlling transport 1) Monitoring of traffic on motorways 2) Congestion zone monitoring 3) Automatic number place recognition (ANPR) 4) Automatic control of traffic lights 5) Air traffic control systems 6) Railway signaling systems 1) Monitoring of traffic on motorways It is used to determine current traffic flows on the main carriageway & traffic demand on the access ramp. 2) Congestion zone monitoring It is carried out to determine the traffic congestion state 3) Automatic number plate recognition (ANPR) It is a system where car plate is recognized & identified automatically.  14 4) Automatic control of traffic lights Traffic lights are sometimes centrally controlled by monitors/computers to allow them to be coordinated in real time to deal with changing traffic patterns. 5) Air traffic control system It is the process/system by which the movements of aircrafts are monitored and directed by ground personnel communicating with pilots by radio. 6) Railway signaling systems It is a system used to direct railway traffic and keep trains clear of each other at all times. Trains move on fixed rails, making them uniquely susceptible to collision. 7) Control of smart road systems and smart signs Many modern motorways are now called smart motorways because the monitoring and control of the traffic and/or the information displayed on motorway signs are controlled by a central computer system to prevent accidents. Rail and airline network control systems It is possible to safely coordinate a large number of trains and airplanes entering and leaving stations and airports. It is also possible to run a more efficient timetable under total computer control. Train and airplane journeys are also safer, because human error is removed - many rail accidents were caused by drivers making mistakes.  15 Advantages of transport monitoring & control system 1. Smart motorways can minimize everyone’s journey time. 2. Transport systems are more efficient allowing for more regular services. 3. Traffic offenses can be automatically penalized using ANPR. 4. Stolen cars & criminals can be spotted using ANPR. 5. Computerized control systems reduce the rate of accidents. Disadvantages of transport monitoring & control system 1. A hacker could gain access to the computerized system and cause interruption 2. If the computer system fails then the whole transport system could be brought to a standstill. 3. Poorly designed systems could compromise safety. 4. ANPR systems can track innocent people’s movements Tuesday 20/8/2024 Autonomous vehicles in transport Driverless (autonomous) vehicles are increasing in number every year. These are very complex robots, but the big problem is not really the technology (because problems will be solved over time ) - it is human perception. We are already used to autonomous trains, as these are used in many cities throughout the world. These systems have been generally accepted ; but that is probably because trains do not overtake other trains and other trains and have a specific tracks to follow. Autonomous cars, buses and vans Autonomous cars use sensors, cameras, actuators & microprocessors to carry out their actions safely. Sensors & cameras allow the control systems in cars to sense the dynamic conditions on a road. They act as the ‘eye’ and ‘ears’ of a car Microprocessors process the data received from cameras and sensors and send signals to actuators to perform physical actions, such as : - Change gear - Apply the brakes - Turn the steering wheel  16 Autonomous cars Cameras catch visual data from the surroundings, while radar and ultrasonics allow the vehicle to build up a 3D image of its surroundings (this is very important when visibility is poor, such as in heavy rain, fog or at night.) Suppose an autonomous car is approaching a set of traffic lights which are showing red. The first thing the control system in the car needs to recognise is the road sign, and then check its database as to what action to take. When the traffic light shows red, the microprocessor sends signals to the actuators to apply brakes and put the gear into ‘park’. Constant monitoring must take place until the light changes to green. When this happens, the microprocessor will again instruct actuators to put the car into first gear, releases the brakes and operate the throttle (accelerator) Security and safety when using autonomous vehicles Autonomous vehicles use sensors, cameras and microprocessors to ‘understand’ their immediate environment. These vehicles run using complex software systems and a large number of external sensors This makes such vehicles rather vulnerable to cybercriminals. The hacker probably is not really interested in gaining control of the vehicle ; they may be more interested in knowing where the car is, where it is going and finding personal information about the owner of the vehicle. HOWEVER, there are many positive sides to autonomous transport. If the security issues can be resolved, all forms of transport will become safer by removing the human element. Vehicles will be able to drive in cities /on open road, and totally aware of their environments, thus removing many of the current safety issues (both vehicles occupants and pedestrians.)  17 Advantages of autonomous vehicles : 1. Safer because human error is removed, leading to fewer accidents 2. Vehicles will operate more efficiently. 3. Reduce traffic congestions. 4. Increase lane capacity (due to better braking and acceleration responses together with optimized distance between vehicles. 5. Reduced everyone’s journey time as there is no traffic jam. 6. Stress-free parking for motorists. Disadvantages of autonomous vehicles 1. Very expensive system to set up in the first place (high technology requirements). 2. Fear of hacking into the vehicle’s control system. 3. Security and safety issues. 4. The system needs to be well-maintained at all times ; cameras need to be kept clean and sensors could fail to function in bad weather. 5. Driver and passenger reluctance of the new technology. 6. Reduction in the need for taxis could lead to unemployment. Autonomous train Autonomous trains make use of a system called LiDar (Light Detection and Ranging) - uses to prevent crashing into other things LiDar uses lasers which build up a 3D image of the surroundings Advantages of autonomous train Improve the punctuality of trains Reduced running costs (few staffs are required) Improved safety because human error is removed It is possible to increase the frequency of trains Disadvantages of autonomous trains The fear of hacking into the vehicle's control system System does not work well with very busy services High initial capital and operational cost A CCTV will be needed to monitor railway stations since there’s no driver  18 Autonomous airplanes Airplanes have used auto-pilots for many years to control fights Human pilots only take over during take-off and landing Some of the main features of a control system on a pilotless airplane would include : - Sensors - detect turbulence to ensure smooth flights and allow a quick stabilization of the airplane - An increase in self-testing of all circuits and systems - GPS - to navigate and conduct speed calculation - Actuators - to control the throttle, flaps and the rudder Advantages of autonomous airplane 1. Improvement in passengers’ comfort 2. Reduced running costs (fewer staff required) 3. Improved safety because human error is removed 4. Improved aerodynamics at the front of the airplane because there would no longer be the need to include a cockpit for the pilots Disadvantages of autonomous airplane 1. Security aspect if no pilot is on board 2. Emergency situations during the flight may be difficult to deal with 3. Software glitches could cause devastating results Potential health problems related to the prolonged use of IT equipment 1) Back and neck strain Causes of health risk : - Caused by sitting in front of a computer screen for long periods of time Elimination/reduction of health risk : - Use fully adjustable chairs to give the correct posture - Use foot rests to reduce posture problem - Use tiltable screen to ensure the neck is at the right angle 2) Repetitive strain injury (RSI)  19 Causes of health risk : - Damaged to fingers & wrists caused by continuous use of a keyboard / repetitive clicking of mouse buttons Elminimation/reduce of health risk : - Ensure correct angle of arms to the keyboard/mouse - Take regular breaks and exercise - Use voice-activated software if user is prone to problems using the mouse/keyboard 3) Eyestrain Caused of health risk : - Caused by staring at a computer screen for long period of time or with incorrect lighting in the room Elimination/reduction of health risk : - Take regular breaks and exercise - Make use of anti-glare screens if the room lighting is incorrect - Users should have their eyes tested on a regular basis 4) Headaches Caused of health risk : - Caused by incorrect lighting, screen reflection, flickering screens, etc Eliminations/reduction of health risk : - Take regular breaks and exercise - Make use of anti-glare screen if the room lighting is incorrect - Users should have their eyes tested on a regular basis 5) Ozone Irritation Caused of health risk : - Caused by laser printers in an office (symptoms : dry skin & respiratory problem) Eliminations/reduction of health risk : - Proper ventilation should exist to lower ozone gas levels to acceptable values - Laser printers should be housed in a designated printers room - Change to use inkjet printers where possible Tuesday 3/9/2024 Chapter 6 : ICT application (Information and Communication Technology)  20 Chapter 6.1 : Communication There are several communication systems that make use of ICT technology. For ex. - Newsletter & posters - Websites - Multimedia presentations - Media streaming - E-publishing 6.1.1 Communication media 1) Newsletters & posters Newsletters and posters can be easily produced using a word processor. Photos were often The sequence to create a newsletter/poster vary depending on what already exists or what needs to be created First is to launch the word-processor application Photos could be obtained by : - Using a digital camera anduy taking photos - Searching for images via the internet or from hard drive - Scanning from hard copy photos Photos would then be save on a file on HDD/SDD Once imported, photos could be cropped/edit Photos need to be place in the correct position and the text wrapped Finally, the documents would need to undergo proofreading for error and then saved, ready for printing Newsletter A newsletter is a very useful and an effective communications tool for getting important information to a target group For ex. , if you’re doing a fundraising exercise, a well-presented newsletter to accompany the fundraising would be invaluable Newsletters can either be printed out or available online as an e-publication. The method used depends on who the targeted audience is. While a printed document that is handed personally to someone can be certain they have seen the newsletter but it is nearly impossible to be certain that they have read it. Guidelines to produce an attractive newsletter Do not try to squeeze too much information on 1 page Use a very clear/easy-to-read fonts with suitable font size Decide on whether to use columns AVOID USING CAPITAL LETTER AS THIS APPEARS TO BE ‘SHOUTING!!!!!’  21 Use bold text in headings rather than underlining text Use real photos rather than clip art to make the newsletter more interesting Friday 6/9/2024 Poster Posters serve as a visual communication tool that can convey information, prompt events, and capture attention. A sporting event poster would need to include at least the following information : - What the event is - Date,time and venue - Admission fee (if any) - Contact details - Other information (such as if there will be a nursery or facilities for people with disabilities, or underage children) A movie poster would need to include : - An image taken from a movie to give some idea of the genre of the movie (e.g. horror, comedy, drama, etc) - The release date of the movie - A list of the main characters Posters can be printed out using high-quality printers or can be posted online Posters can be printed in any size. Big posters are eye-catching and usually placed on the side of roads so motorists see them on their way to work or vice versa In terms of suitability, they are usually placed in strategic position/location to attract certain group of people rather than the general public. For instance, advertising expensive cars by placing the posters on buildings or advertising billboards in financial district Drawback : cost of display may be high as the advertising areas can only be rented and posters are subjected to weather conditions.  22 Websites Reasons of having a website 1) Gives visibility to your business 2) Makes it easier for your customers to find information about your business 3) It is a very powerful sales channel & allows you to promote offers 4) Allows you to earn money online 5) An excellent channel to interact with your clients 6) Creates & enhances your brand images 7) It helps you to create collaborations with other companies and recruiting employees 8) You can share business news and sector needs 9) It allows you to see what your clients are most interested in 2 methods of advertising : Method 1 : Requires a company to either develop their own website Method 2 : Pay another company to advertise on their websites Method 1 : It is necessary for a company to buy hardware and software to develop to store the website Expensive May to engage programmers if lack skills to make sure that their website is safe from hackers & from pharming attack - (lead user to a fake website instead of the real website the user intended to visit)  23 Method 2 : Paying another company on their website is a common practice known as display advertising or online banner advertising This type of advertisement involves placing visual ads on another company’s website to promote their products or services Multimedia Presentation - Use of sound and animation/video effects are Advantages of multimedia presentationmore likely to grab the attention of the audience - Easier to understand - Possible to have interactive hyperlinks built into the presentation - Can be interactive - Presentation can be tailored to suit a particular audience - Disadvantages of multimedia presentation - A need to have special equipment can be expensive - Danger that equipment could fail during a presentation - May need internet access - Very easy to make a bad presentation with too many animation effects & too much text or images Media Streaming Media streaming is when users watch movies/videos or listen to music on devices connected to the internet Streaming is continuous transmission of video or audio files from a remote server where the files are stored However, by downloading the video/audio files on the computer’s HDD/SSD, playback is possible at anytime but it uses up a considerable amount of storage space When streaming, the file is sent as a series of packets of data and every packet is interpreted by the web browser Buffering Buffering is the process of preloading data into a reserved area of memory. We called it a buffer. In the context of streaming video or audio, buffering is when the software downloads a certain amount of data before it begins playing the video or music.  24 You can watch the data stored in the buffer while the next portion of the file downloads in the background. This preloading process ensures a smooth playback process without interruption. E-publication Most material which is published on paper is also available in an electronic format. For example : - E-books - Digital magazines - Digital newspapers - Digital libraries In all cases, the publication can be downloaded to a device connected to the internet where it can be read. Moving between pages in usually done by swiping a finger across the screen. The pages can be expanded in size (the zoom-in & zoom-out capability) which was not possible with the more traditional paper-based publications. As there is no printing costs incurred, e-publications are usually cheaper than their paper-based counterparts. Tuesday 24/9/2024 6.1.2 Mobile communication - Mobile phones communicate by using towers inside many cells networked together to cover large areas. - The towers allow the transmission of data throughout the mobile phone network - Each towers transmits within its own cell. (eg. You are driving a car and get to the edge of a cell, the mobile phone signal starts to weaken) - This is recognised by the network and the mobile phone then picks up the signal in one of the adjacent cells. - If a person is making a call or sending a text to somebody in a different country, then satellite technology is used to enable the communication to take place. Mobile devices either use : - - A SIM (Subscriber Identity Module) card to allow it to connect to the mobile phone cellular network - Use wireless internet connectivity  25 Both allow the following features : -SMS messaging -Phone calls -Voice over Internet Protocol (VoIP) communication -Video calling -Internet access SMS (text) message Features of SMS include : - Quicker & less expensive than making phone calls - Can be sent at any time of the day even if the recipient’s phone is switched off - Predictive texting, where the system completes a word from the first few letters keyed in. E>x. key in “preci”. It also allows the system to remember frequently used words - together they increase typing speed. Phone calls - Mobile phones can be used to make phone calls - Mobile phones are small in size - Have their own power source (aka the battery) - Allows people to keep in touch anywhere provided there is a network signal - However, it is not as stable as landline systems Advantages of using mobile phones to make phone calls : - There is no need to look for an operational public telephone in an emergency - It is possible to conduct business or personal telephone calls on the move - Able to keep in touch with co-workers at the office no matter where are you 3) Voice over Internet Protocol (VoIP) and video calling (VC) -VoIP is having a telephone conversation via the internet -VoIP converts sound picked up by mobile device’s internal microphone, into discrete digital data packets that can be sent their destination via the internet (Analogue —> Digital —> Send) -One of the biggest advantage is that phone calls are free, wherever in the world the callers & receivers are -The device’s build-in cameras can be used so that it becomes a type of VC  26 -VC’lling such as FaceTime (for Apple devices) has the split screen feature that allows you to see a number of people simultaneously Key features of VC include : - Live video & audio chat - Screen-sharing during the call - Recording during sessions One of the shortcomings(disadvantages) are usually sound quality - Security threats include : Identity theft, viruses & malware, spamming & phishing attacks - Relies on good broadband / mobile phone network coverage - User are required to download app such as : -FaceTime & Zoom Internet access Is made possible using a wireless broadband connected / via a mobile phone network (SIM card) Internet pages displayed on mobile phones are often different to those of desktop/laptop computers The software detects the type of device is connecting to a website, which then sends out the webpage optimized for that device Wireless broadband connectivity has the following advantages : - Less expensive (Mobile phone company ‘data plans’ often have a cap on how much data can be downloaded & charge for exceeding this maximum) - Lower power consumption (Wi-Fi routers are usually much closer than mobile phone towers, the longer the range, the greater the power consumption) - Quality of server (Wi-Fi usually offers greater bandwidth than the mobile phone network giving the possibility of downloading more data quicker, for e.x. Using a mobile phone in Damai Beach network is weak ; when get back home network is strong. Examples questions (Mobile Communication): 1) What happens when the mobile phone gets to the edge of a transmitting tower? - The mobile phone signal starts to weaken & picks up the signal in one of the adjacent cells.  27 2) The following are features of SMS expect : A. Quicker to send B. Can be sent at any time of the day C. Predictive texting D. Free SMS 3) Mobile network is more stable than the landline system. True or False - False 4) What are the security threats to VoIP? I. Identity thief II. Viruses & malware III. Spamming IV. Pharming attack A. I, II, III B. I, II, IV C. II, III, IV D. I, II, III, IV 5) Which of the following are TRUE about the advantages of using a wireless broadband ? I. Good mobile phone network coverage II. Quality of service III. Lower power consumption IV. Less expensive A. I, II, III B. I, II, IV C. II, III, IV D. I, II, III, IV Friday 4/10/2024 Bridge and building design When an engineer or architect designs a new building or bridge, it’s necessary to test the design before any construction work begin.  28 A 3D computer modelling is used to try out a number of scenarios to ensure the final design meets critical criteria. Simulation of the final structure is often done as a combination of computer modelling and wind-tunnel tests on scale models of the final design. When building a bridge, a model has to consider : - The amount of traffic that might be caught in a traffic jam on the bridge in the event of an accident as it could lead to very heavy loading on the bridge structure. - The effects of strong wind —-- can the bridge design within the worst-case scenario. - The effect of earthquake —-- is the bridge earthquake-proof - The effect of tidal waves and ice floes during extreme weather conditions —-- can the pillars supporting the bridge withstand these condition - The effect of vibration —--- there have been cases over the years where bridge have collapsed due to for example, wind causing the bridge to sway at its ‘natural frequency’ All of these scenarios can be tested using a computer model The design can then be modified on the computer if any above scenarios caused the bridge to fail After a number of modifications, a final design will be decided on. This is to ensure the computer model gives good results A scale model of the bridge would then be constructed and subjected to wind-tunnel (and other) trials. When testing the building using a computer model, a number of scenarios need to be considered : What is the effect of natural phenomena, such as hurricane winds, flooding, earthquakes, & other potentially damaging phenomena ? The effects of a disaster, such as fire —--- how does the structure stand up to such scenarios? How is it possible to move people around building efficiently? Computer modeling provides the following features : It is possible to zoom into images so that fine details can be seen The design can be rotated in a number of different ways to allow different views of the design to be made Building a bridge or a building is expensive & dangerous if the final design had a serious flaw Various scenarios can be tried out to see the effect on the design  29 Flood water management -Flood water management uses computer modelling to perform a risk assessment to identify : 1. Sources of potential flooding 2. The extent of flooding 3. Any mitigation or protection measures that could work -Computer models are used to predict water levels, water flows & potential flood depths. Input to the system could include : 1. Cross-section of rivers & sea inlets (e.g. bottlenecks) 2. Dimensions of any bridges, weirs or sluices in the flood area - A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. - Sluice —------- A sliding gate or other device for controlling the flow of water, especially one in a lock gate. 3. Factors that can affect water flow rates - High tide & low tide 4. Once a model exist which simulates the area where there is potential flooding, a plan can be put forward to guard against future flooding Some of the measures that must be taken to prevent more flooding in the future (remember at least 3 :3) - Introduce better flood warning systems - Modify homes and businesses to help them withstand floods - Construct buildings above flood levels - Introduce water storage areas - Put up more flood barriers It is possible to try out several different solutions using the model before actually building any flood defences The advantages of computer-based system include : - Sensors could be used out in the bay area to monitor sea height and wave height  30 - It is safer since it is risky to put humans to monitor conditions - Data collection is continuous and more accurate than manual measurements - People who lives in cities could be warned well in advance if any flooding actually taking place Traffic management -Computer modelling consider 2 different situations in traffic management 1) Closure of motorway lanes 2) Traffic light simulation -Closure of motorways lanes 1) Repair needs to be made to part of the central barriers on an eight-lane motorway 2) The company -(JKR) given the task of carrying out these repairs need to model the impact of the roadworks on the traffic flow 3) The model will also test on the effects of different speed limits through the roadworks to see how it would impact the traffic flow 4) Simulation is safer, cheaper and much quicker than trying out different traffic closures on a real motorway -Traffic light simulation 1) Computer modelling a set of traffic lights at a Y-junction 2) In simulation it is necessary to consider : - How and what data needs to be collected - How the simulation is carried out - How the system would work in real life -How & what data needs to be collected 1) Induction loop sensors which count the number of vehicles at each junction is used 2) However, manual data collection is also possible but it is prone to error & is difficult to curry out for e.g. over a period of 18-hour per day 3) The following data is an indication of what would need to be collected : - The number of vehicles passing the junction in all directions - The times of day needs to be recorded along with a vehicle count - How many vehicles build up at the junction at different times of the day - Data should cover weekends and holidays - How long it takes a vehicle to clear a junction - Nearby pedestrian crossing (if any) - How long it takes the florist vehicle to pass through the junction  31 How is simulation carried out? - Changing the timing of lights of the lights and observing how the traffic flow was affected - By changing the number vehicles stopped at park of the junction and then changing the timing of the lights to see how the traffic flow is affected - By increasing & decreasing traffic flow in all directions - Considering how emergency vehicles affect traffic flow at different times of the day Weather Forecasting -Weather stations are set up to automatically gather from the environment -It measures : 1) Rainfall 2) Temperature 3) Wind speed 4) Wind direction 5) Barometric pressure (air pressure) 6) Humidity  32 1) What is modelling application ? Ans ; Modelling applications are software tools used to create simulations or representations of real-world scenarios or concept 2) Name 4 advantages of using a model Ans : Cheaper, safer, greater range of situations, saves time 3) Fill in the blanks -The principle of using a spreadsheet is to carry out any type of modelling that can be represented in a mathematical form -Spreadsheets are often used to carry out financial modelling 4) What does a modeller need to consider when building a bridge Ans : The effects of earthquakes, the effects of strong wind, the effect of vibration 5) Fill in the blanks Computer modelling provides the following features : - It is possible to zoom into images so that fine details can be seen - The design can be rotated in a number of different ways to allow different views of the design to be made - Building a bridge or building is expensive and dangerous if the final design had a serious flaw - Various scenarios can be tried out to see the effect of the design 6) Suggest 3 ways to prevent flooding in the future Ans : Introduce better flood warning systems, construct buildings above flood levels, introduce water storage areas 7) In terms of traffic management, HOW & WHAT data needs to be collected ? HOW : -Induction loop sensors which count the number of vehicles at each junction used WHAT : -Nearby pedestrian crossing -How long it takes the slowest vehicle to pass through the junction -The number of vehicle passing through the junction in all directions 8) What data does a weather forecasting measure?  33 -Rainfall -Temperature -Humidity -Wind speed -Wind direction -Barometric pressure (air pressure)  34 LSA -20 obj (20m) -5 acronyms (5m) -5 fill the blank (5m) -The rest short answer (advantage and disadvantage (mostly advantage) at most need 3 advantage) (20m) Tuesday 5/11/2024 6.3 Computer Controlled System 1) Robotic in manufacturing 2) Production line control Robots in manufacturing Robots are controlled either through embedded microprocessors or linked to a computer system It’s possible to program robots to do a series of tasks. The tasks can be done in 2 ways i. A robot programmed with a sequence of instructions which allows it to carry out a series of tasks. ii. Human operator manually carries out a series of tasks : - The robot arm is guided by a worker when spraying the object. - The worker straps sensors to his own arm & sprays the object. Advantages in using robots - They have higher productivity & consistency. - They r good at doing repetitive tasks that r boring to human. - They can carry out different tasks by fitting them with different end-effectors. (attachment) - Can work in dangerous situations. - Can work non-stop. - Less expensive in the long term. Disadvantages in using robots - Difficult to do unusual tasks (e.g. unknotting Christmas lights) - Cause high unemployment - Loss of technical skills (e.g. welding) - Initial set up & maintenance of robots can be expensive  35 2) Production line control - Robots r used extensively in a production line control. i) Filling bottles with a liquid, capping the bottle & applying labels. ii) Filling metal cans with baked beans, sealing the cans & applying labels. - Robots r situated at different station for a specific task. Using robots in this way leads to : i) Faster operation (120 cans of baked beans filled in a min) ii) Greater productivity (production can be 24/7) iii) Greater consistency (every can contains exactly the correct weight of baked beans) iv) Built-in-quality control (automatic testing for foreign materials such as metal fillings, which would result in automatic rejection from the production line) v) Reduce cost to customers (few staff is factory who need wages) Assessment Questions :3 1. The control of robots in manufacturing is through embedded microprocessor only. True or False? Ans : False 2. Name 3 advantages in using robots Ans : - Can work non-stop - Can work in dangerous situations - Less expensive in the long term  36 6.4 School Management Systems (SMS) - Schools have to manage a number of different tasks in their day-to-day running. These tasks include : 1) Registration & attendance records of students 2) Student performance 3) Computer-aided learning (CAL) 1) Registration & attendance records of students - Traditional ways of recording are prone to error if a student’s name was missed & it takes time - However. There r 2 methods of automating the registration process : - Method 1 : The use of magnetic stripe card - Method 2 : The use of biometric scanning (may come out in uasa) Method 1 Method 2 The magnetic stripe world contain the : - Each student would have their fingerprint - Name of the school recorded - Name of the student - Their personal details (in Method 1) plus - Student’s DOB (Date Of Birth) fingerprints would be stored on a database - Student’s unique ID - Knowing each students has unique fingerprints, this system would be very secure -The data read would identify the student & the time & data they entered the school’s premise. These data would Advantages of biometric compared to the use of magnetic then be stored in a database ID cards : - It’s impossible for a student to sign in pretending -When leaving school, the ID card would again be swiped. to be someone else. This improves security This would now record the leaving time and data in the - ID cards could easily be lost but fingerprints r database “part of u” so cannot be lost - It’s much easier to “clone” ID cards than it would -At the end of the semester (or school year), the database be to copy fingerprints could be interrogated and it would give an accurate attendance record for the student Disadvantages of biometric compared to the use of magnetic -This attendance record could be sent out to parents or ID cards : checked by teacher on a regular basis - It would take a long time to collect all of the student’s fingerprints in the school. - Equipment needed to read fingerprints is more expensive than magnetic stripe reading equipments - If a student cuts a finger, the fingerprint may not be able to be identified by the system - There r invasion-of-privacy issues & a number of students and parents may object to having  37 fingerprints stored on a database 3) Computer-aided learning (CAL) -Computer-based system aimed to assist in academic teaching of students -Used to enhance learning, but not to replace the traditional classroom teaching method. Disadvantages of CAL - Expensive and time consuming to integrate CAL properly into the learning environment - Lead to social isolation as they're spending time in front of a computer screen 6.5 Booking systems - Online booking system(OBS) rely on the ability to update the file immediately to prevent double-booking, which could happen if the system response time was slow - OBS r used in : 1. Travel industries 2. Concerts 3. Cinema tickets 4. Booking sports events Advantages of OBS : - To prevent double-booking - Bookings can be made at any time of the day - QR code is stored on the device & only needs to be scanned at (e.g. the theatre or airport on arrival) - Customers can receive emails about “special offers” automatically - Customers get immediate feedback on the availability of seats & whether or not their booking is successful - It’s possible to browse the seating planes to choose the best seats at the best prices - It’s possible to “reserve” a seat for a period of time Disadvantage of OBS : - The setting up & maintenance of obs is expensive - No refunds after the purchase - If the server breaks down or under maintenance, it is not possible to book any seats by any method - All customers need to access to a computer for mobile phone with a reliable connection - It could be difficult to make the bookings you wanted if the website is not well designed  38 - For e.g. , we will consider booking a flight online. A form similar to the one shown below would appear on the screen - The user needs to fill in the appropriate fields & the system will automatically search for available flights, make bookings & transfer the funds from their bank account Booking a football stadium Step 1 The customer will need to select the event, the required days, number of people & preferred seats Step 2 The database will search to check for available seats for the chosen date Step 3 Available seats will not be shown on the booking map like a concert or cinema’s booking system, if a seat is available, the customer will be offered seats in the block Step 4 If the customer is happy with the option, they simple confirm the booking & payment is made online Step 5 Once confirmation has been made, it will be sent as an email or a QR code, which can be downloaded to the customer’s smartphone ; this QR code will act as their event tickets. Extra #1 However, some sporting events don’t book seats, in which case the booking will simply be the entry of the event (aka sitting anywhere you want) Extra #2 One additional feature is the ability to also book flights & hotels if the event takes place overseas Chapter 6.6 Banking system Banking applications - The use of computer technology has revolutionised how we all do our banking transactions. Here, we will consider : 1) The use of automatic teller machines (ATMs) 2) Electronic funds transfer (EFT) 3) Credit-debit card transactions 4) Cheque clearing 5) Internet banking  39 Automatic teller machines (ATMs) - An ATM allows the customer to : 1) Withdraw cash (don’t write “money”) 2) Check the balance of their account 3) Deposit cash 4) See a mini bank statement 5) Pay a bill 6) Money transfer Sequence for withdrawing cash & what does on behind the scenes 1) Customer puts card into ATM - Contact is made with bank’s computer 2) Pin is entered using the keypad - PIN is checked to see if it’s correct, if it’s not correct, customers will be asked to retype the PIN - The card is checked to see if the card expiration date is exceeded or if the card was reported stolen - If the card was stolen or if the number of PIN attempts exceeds 3, the card will be retained & transaction will be closed 3) The customers selects to withdraw cash 4) A number of cash amounts are shown 5) The customer accepts one of the cash options or - Customer’s account is checked to see if they have types in a different amount sufficient funds - A check is then made to see if they detail cash limit has been exceeded - If limit is not exceeded & all other checks r fine, then the transaction is authorised - The cash is then counted out the cash 6) The customer is asked if they want a receipt 7) The card is returned 8) Money is dispensed - Customer account is updated CDM = Cash Deposit Machine  40 Credit/debit card transactions Credit card - banks money (if usual deposited money is around RM20-50, but suddenly turned to RM100, bank will contact and ask for verification of the owner of the credit card whether they are the one who made it. Debit card - ur money Supposed a customer goes into a restaurant to pay for a meal using a chip & PIN card : - The PIN is entered using a keypad or unless it is a payWave - The card is checked to see if its valid - The PIN is read from the chip on the card & is compared to the one just keyed in - If the PIN is the same, then transactions can be made Alternate : - If the PIN is different, the transaction will be terminated - The restaurant’s bank contacts the customer’s bank - A check is made on whether they have enough funds/money - If everything checks out OK then the transaction is authorised - An authorisation code is sent to the restaurant - A receipt is produce as proof of the purchase Advantage of credit card : --Internationally accepted method of payment -Interest-free loan if the money paid back on or b4 the due date -There's a customer protection if a company stops trading or goods do not arrive -Can buy items online Advantage of using debit card : -Safer than carrying cash (Debit Card) -Can buy items online (Both) Disadvantage of credit card : - Easy to end up with credit damage - Annual fees often apply - Can be charged with high interest rate Disadvantage of debit card :  41 - Less customer protection than if good does’t arrive or company goes out of business - Poorer security risks when online - No credit allowed, customers must have the funds available Cheques - Cheques r the one of the oldests way of paying somebody for services or good - It’s more expensive, slower & less secure way of making payments, they r being slowly phased out Advantage of cheque - More convenient & safer than cash - It’s possible to stop payments if necessary - Cheques can be post-dated - Can be traced if they r lost - A cheque can be drawn any time Disadvantage of cheque - Cheques r not a legal tender & can be refused - Relatively a expensive payment method - Easier for fraudster than credit or debit card payment method - It’s a slow method of payment - 42 43  44 Chapter 1,4,5,6-6.6 why :( USAS - 20 objective (all disadvantages yay :3) - 15 acronyms - 45 marks - 10 fill in the blanks (answers given) (e.g. dsnuf = funds) - Section C (all advantages yay :3) -35 marks - More question is on chapter 6 & 4  45 *what is spread-spectrum frequency hopping? *3 type of cloud computing systems (6m)