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Before you start this topic, recap AS work
Before you start this topic, recap AS work
What you need to know for A2:-
What you need to know for A2:-
Types of software - Explain the use of a range of types of software including safety related, control, expert, wide and local area information exchange systems.
Safety related systems - Explain that some computer applications are safety related and require a high level of dependability, and hence that the development of safety critical systems is a highly specialised field
A safety critical system is one in which a malfunction or failure of computer hardware or software could potentially put persons at risk of injury.
How do you ensure a system is safe?
• Exhaustive testing of systems must be carried out before they are brought into service.
• Systems should have redundancy where possible (e.g. a backup computer can be brought into use immediately if the main computer fails).
• Systems should be designed to be fail-safe (e.g. a train will safely come to a halt if a malfunction is detected or auto-pilot should work on an aeroplane).
• Regular maintenance and testing should be carried out (e.g. of outdoor cabling which might be affected by rainwater, or control equipment on a train which might be affected by vibration)
• High levels of security must be maintained, to guard against malicious attacks..
Examples
Driverless cars or trains
On-board computers for aeroplanes
Nuclear Plants
Control systems - State the nature and scope of computer control and automation.
Control systems - Describe the benefits and implications of automation.
A control system manages, commands, directs or regulates the behaviour of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large Industrial control systems which are used for controlling processes or machines.
All control systems will require inputs and output to ensure it is correctly control and can be acted upon when required.
Example
Input of a train - Monitoring speed Output - Apply braking as necessary
Input of a train - Monitoring geographical location Output - Apply braking as entering a station
Input of a train - Monitoring track ahead Output - Apply braking if an obstruction is detected
Input of a train - Monitoring the track ahead Output - Don't move if doors are open
Input of a train - Monitoring fire warning systems Output - Take emergency action if fire is detected
Automation is the term used for technology applications where human input is minimised. Automated jobs are increasing as well as applications.
Automation includes:-
The use of robotics in the manufacturing industry
Automated cars
Navigation systems
Power Back ups (UPS) that automatically come one if their is a power cut
Barriers to car parking or across railway lines
With these system, an input, process and output are required.
Benefits of automation
No possibility of human error
Humans not subject to dangerous conditions
Safer environment
Work efficient so you know output e.g. no human variables such as sickness, lateness
Can work 24/7
Computer may apply optimisation algorithms to ensure system is efficient as possible
Data collection from system to constantly improve and update system
Constant monitoring of systems so can respond to feedback
Security implications to look at
security will need to be incorporated from initial analysis and design of system and constantly monitored / updated
techniques such as penetration testing should be employed – deliberately attempting to identify security vulnerabilities
white hat (ethical) hackers employed to carry out penetration testing and other testing techniques
danger of viruses / worms being deliberately introduced by USB sticks, remote access to system
need to consider loss of production / damage to equipment
need to consider injury / death of employees / persons in the community
need to consider company’s reputation in the community
motivation of malicious behaviour could be standard criminality such as blackmail or could be terrorism
staff vetted to attempt to prevent internal malicious damage
security staff / physical locks / biometric methods to prevent unauthorised physical access.
Uses of Robotics in Manufacturing
Robotics could be used in accurate assembly lines such as the production of circuit boards or making of cakes
Carrying out unhealthy or dangerous activities such as car body welding or spray painting cars or bomb detection and disposal
Repetitive operations such as packing food items into boxes
Warehouse functions such as collecting selected items from shelves
Look at the videos below to see some of these in action. Things like have you ever thought - How can Amazon deliver something within 24hrs but no other company can?
Advantages of Robotics
• Lower prices due to reduced manufacturing costs.
• Consistent quality due to accurate manufacturing.
• Faster delivery times.
• Quicker innovation for new products.
Problems that can arise with Robotics
• Need for retraining of the workforce to operate new technology
• Cost of specialist technicians and programmers
• Risk of breakdown of a complex system affecting production
• Cost of adapting factory premises for automation / Initial setup costs
• Risk of malicious damage by hackers
(NOT the loss of jobs)
Expert systems - Discuss the possible effects of expert systems on professional groups and the wider community
An expert system is a system that provides an expert opinion based on human knowledge. It has three parts:-
knowledge base
Inference engine
User interface
Features of an effective expert system
• An expert system uses an inference engine, knowledge base of facts and rules for decision making.
• Facts and rules should be produced by a specialist with relevant expertise, using the best available information.
• The user is asked a series of questions. Subsequent questions may vary according to the answers given.
• Question sequences should be designed so as to gather the necessary information needed for decision making for all valid sets of input values.
• The user interface should be user-friendly, with adequate help and error trapping during data entry.
• The system should generate results on screen or on paper in a format which is clearly understandable to the user.
• The system should list its results in order of suitability, or indicate a relative value or score for each.
• The system should explain its reasoning in reaching its decisions, so that the accuracy of the results can be evaluated.
Uses of an expert system
Medical diagnosis
Careers advice
Diagnosing car faults
Decision on mortgage or loan or insurance premium
Telephone lines such as broadband issues or 111 hospital/police https://111.nhs.uk/
Limitations of previous expert systems have been overcome with new methods of AI and machine learning and data mining.
Benefits of an expert system
explaining the input stage of the system (e.g. providing a sequences of questions on-screen)
explaining the processing stage (e.g. the program asks different questions, depending on responses received, until sufficient information obtained to make a decision.)
then processes facts according to a set of rules.
explaining the output stage (e.g. a diagnosis and treatment advice is presented on screen)
the program comments on how the conclusion was reached, explaining its reasoning. This allows the user to evaluate the validity of the decision.
the program indicates the certainty of the result produced (e.g. there is a 70% change of outcome A, but 30% chance of outcome B). This alerts the user to possible alternative solutions.
advantages of the expert system to the user (e.g. faster and more consistent loan application decisions, more accurate medical diagnosis with less chance of important symptoms being overlooked.)
Can easily be kept up to date.
Helps to give a more accurate decision.
Does not get ill, retire, go on holiday, etc.
Gives a second opinion.
Available 24/7.
Allows access to an expert where not available locally.
Provide significant clerical time and labour savings.
Increase competitive advantage / Improve company efficiency / Significantly increase company profitability.
Used to centralise decision making (more consistency).
Allow lower management levels to make decisions / Allow better use of management time.
Allow broader distribution of expertise throughout the company.
A good expert system explains its decision so that a user can decide whether to accept the decision or not
Expert systems can learn from experience
Allows employees to learn from the system
Internet and Intranet - Describe the use of search engines on the internet.
Internet and Intranet - Describe common contemporary applications.
Internet and Intranet - Discuss the possible effects of the internet upon professional groups and the wider community.
*** When you type a word into a search engine, how does it know which website should go at the top of the list? ***
Modern search engines use complex indexing and ranking algorithms to ensure that you get instant access ot the most relevant websites - or a at least to the websites the search engine algorithms most want you to visit.
Search engine indexing
Search engines collect information about webpages using automated bots called spiders. These bots scour the internet, following links and recording keywords and the addresses where the keywords are found. This information is then transmitted back to the search engine provider. This is why when you use different search engines such as Google, Yahoo or Bing, you will be shown different results. The information sent back is then stored according to an index, for example keywords. When we use search engines we are not searching the World Wide Web - we are simply searching the search engine's index of the Web. This is why searches can return answers in 0.00002 of a sec!
PageRank algorithm
Search engines companies alayse their indexes using algorithms. The PageRank algorithm is Google's way of generating a rank order for the websites found in response to users' searches. It was named after its inventor Larry Page. The PageRank algorithm, works by counting the number of links to a page from other websites. This gives Google a rough estimates of how important a website is; more important websites are returned higher up the search results. The infromation about webpages (like the number of links) is gathered by an automated web spider called a Googlebot.
The algorithm represents all the webpages as vertices on a directed graph data structure and the hyperlinks between pages are stored as edges within the same structure. Vertices are assigned a numerical value representing their importance (based on the number of links to them) PageRank is no longer the only algorithm used by Google but it was the first and still the best known.
Uses of the Internet
Podcast
A series of digital media files (either audio or video) that are released episodically and often downloaded through web syndication.
The mode of delivery differentiates podcasting from other means of accessing media files over the Internet, such as direct download, or streamed webcasting.
A list of all content is maintained on the distributor's server as a web feed. The user employs special client application software known as a podcatcher that can access this web feed, check it for updates, and download any new files in the series.
This process can be automated so that new files are downloaded automatically. Files are stored locally on the user's computer or other device ready for offline use at a later date, giving simple and convenient access to episodic content.
Blog
A type of web site usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video.
Entries are commonly displayed in reverse-chronological order.
Most blogs reflect the thoughts, opinions, and biases of the individual or corporation that runs the blog.
Most are also interactive, allowing visitors to leave comments and even message each other via widgets on the blogs. This interactivity distinguishes them from other static web sites.
Instant messaging
A form of real-time direct text-based communication between two or more people.
Messages are usually encrypted to maintain privacy
More advanced instant messaging software clients also allow enhanced modes of communication, such as live voice or video calling.
IM falls is a form of online chat, but is distinct in that it is based on clients that facilitate connections between specified known users whereas online 'chat' also allow communication between anonymous users in a multi-user environment.
Differs from e-mail due to the perceived synchronicity of the communications
Webcast
Broadcasting over the Internet.
A webcast is a media file distributed over the Internet using streaming media technology.
Distribution of a single content source to many simultaneous listeners/viewers.
May either be distributed live or on demand.
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