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CCEA A2 Digital Technology > Factfiles > Flashcards

Flashcards in Factfiles Deck (23)
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What is a database?

Collection of data items structured so that data can be searched and retrieved when necessary. Flat file or relational.


What is the issue with flat file?

Entire database in one file. Row for each record + column for each field. Leads to data duplication, inconsistency + poor integrity.


What is the difference between integrity and inconsistency?

Inconsistency - data keyed in wrong and right in diff places.
Poor integrity - unreliable data due to being inconsistent.


Describe portability in terms of a relational database?

Relational model is standard. Data should transfer between relational systems easily.


How do you write data in unnormalised form?

Primary keys underlined
Foreign keys have *.
Fields all contained in brackets ()
Repeating groups in {}.


What are the disadvantages of normalisation?

Complex, has more tables, may be slower, need more relationships + queries can be more complex with more tables.


What do communication protocols regulate?

Message formats, authentication methods, error detection and correction methods, how data is split into packets and how data packets are sent + received.


Compare impact of cable failure on data transmission over star and bus?

On star, each node connected to hub by own cable. In bus, connected to main backbone where all messages sent. In star, if cable fails, only 1 device affected. In bus, if connecting cable fails, only that device fails but if backbone fails, all communication affected.


How is Bluetooth used for data transfer between a computer and a mobile device?

Creates ad hoc networks called piconets. All devices must be Bluetooth enabled. Devices must be paired.


How is wi-if used for data transfer between a computer and a mobile device?

All devices must be WiFi enabled and have WNIC. Must all be connected to same router. Data sent via wireless connection through switched hub, ensuring data is sent to intended recipient.


Compare fibre optic + metal cables in terms of security.

Fibre optic are more secure. Transmit data via light pulses. Difficult to intercept without destroying data.
Metal are less secure. Can be tapped into using listening devices wrapped round them as they transmit signals using electricity. Copper makes it much less secure.


What is a captcha?

Completely Automated Public Turing test to tell Computer and Humans Apart. Challenge response test used in computing to determine whether user is human.


What are the 4 main pillars of AI?

Perception, learning, natural language processing + reasoning.


How would an expert system for diagnosing illnesses in a hospital be created?

Medical staff interviewed and wide range of medical reference materials reviewed by system designer to extract knowledge, including any intuition or rules of thumb. Expert systems shell may be used.


Evaluate the use of an expert system for diagnosing faults in cars.

Contains knowledge of num of car designers/mechanics. Can produce accurate diagnoses consistently + provide reasoning. Can’t replace human intuition and risk of over reliance on tech so human expert knowledge may be devalued.


Describe the user interface in an expert system.

User inputs details about issue + receives solution & explanation.


Describe the inference engine in an expert system.

Locates appropriate knowledge in knowledge base. Infers new knowledge by applying logical processing + problem solving strategies. May apply fuzzy logic.
Applies rules using user’s input + draws conclusions.


Describe the knowledge base in an expert system.

Contains info/rules about problem domain/expert knowledge. Represents knowledge of human experts.


Describe how staff could assist development of expert system.

Staff questioned by designer. Contribute to knowledge base + explain how they do stuff, including intuition/rules of thumb.


Describe the role of an expert systems shell.

Software development environment for creating expert system. Contains components of expert system like knowledge acquisition, base, inference engine + used interface. Can be populated for particular application.


Describe the role of the knowledge engineer.

Obtains knowledge required for expert system using structured/unstructured interviews/problem solving/concept maps. Structures knowledge into database + validates it.


Describe the role of a life insurance consultants.

Provide knowledge by describing their experiences + knowledge of life insurance + rules + heuristics they use.


What is different about dates in SQL?

Write them backwards.