comp sci again lol

importance of documentation

• it allows for future maintenance of the system because the organisations needs may change causing the system to be changed

• it allows other system developers ti understand and carry on with the system development

  • it gives instructions to users on how to use the system

what is found is documentation?

1. system flowchart

2. entity relationship tables

3. data flow diagrams

4. structure diagrams

the internet

the internet is a global network of connected computers which is public and does not belong to anyone

services provided on the internet

• e-mail

• e-commerce

• social media

• maps

• e-health services

cloud computing

the is the storing managing and processing of data online, instead of your own physical computer or local server

search engine

a program designed to search for information on specific keywords supplied by the user from the www

intranet

a private network that is similar to the internet in functionality, but is only available to an organization internally

extranet

is a private network that uses internet technology and the public telecommunications system to securely share part of s buisness’s information or operations with suppliers, vendors, partners and customers

Social media

• refers to websites and applications that are designed to allow people to share info quickly

uses of social media

• communications

• collaboration

• entertainment

• marketing

• learning

video conferencing

• this is a facility which allows people from different geographical locations to meet in real time

advantages of video conferencing

1. no need to travel to the meeting venue

2. no need to hire special venue for the meeting

3. meetings can be held at short notice

things needed for video conferencing

1. webcam

2. sound card

3. speakers

4. microphone

online banking

• when customers do banking transactions via the internet

risks of online banking

• bogus sites

• confidential info can be stolen

• making use of the internet can expose customers to viruses

Network security

• is the protections of information and resources over a network from loss, corruptions and improper use

general benefits of wireles netowrks

• avoiding use of network cables the reduce setup costs

• convenience; any can access his or her network resources from any locations within wireless coverage area

• Mobility; you are no longer restricted to your desk

• productivity; this helps your staff get the job done on time despite not being in the office

• expandable with existing equipment

use of computers in banking systems

• a large database is used to store the details or the bank customers as well as their account details

use for stock control systems

• computers are used in shops to monitor the levels of stock so that should not run out stock without knowing 

use of computers in hospital administration

• used to keep records of patients

• keep records of diagnosis and make reminders of medications

use of computers in payroll systems

• systems are used to calculate the the right amount and what they are to be given

use of computers in weather forecasting

• computers can be used to predict weather

how the data for predicting is collected

• sensors are placed in a radiosonde, which is then released into the atmosphere

• the collected info is then sent to earth based weather stations where it is used

• doppler radar and remote controlled drones are also used

computer aided design

• used of computers to create precise drawings or technical illustrations of physical objects

Cad libraries

• saves time

• objects are more accurate

• preserves uniformity

• easy to link to other docs

Simulation

• is the creation and analyzing of a digital prototype of a physical model to predict its performance in the real world

Modeling

• is the process of representing a model which includes its constructions and working

types of simulators

• take-off

• man-oeuvres

• steady flight

• landing

why modelling is done

• dangerous situations can be modeled safely

• no consequences if anything goes wrong

• much cheaper

• can be repeated

Virtual reality

• this is an interactive 3d generated computer created world that you can explore

uses of vr

• used in difficult / dangerous environments

• Entertainment

• training

Monitoring systems

• is a computerized process for checking what is happening around 

Control system

• consists of a microprocessor, a control program and controls the environment

nanotechnology

• is a manufacturing technology that makes products, lighter, stronger, cleaner and less expensive

uses of nanotech w energy n stuff

• generating steam from sunlight

• producing high efficiency bulbs

• storing of hydrogen for fuel cell powered cars

nanotech in cleanup

• carbon nanotubes can be used to trap greenhouse gasses'

• harmful chemicals can be neutralised

  • manganese oxide nano wires can be wires used to clean up oil

nano drones

• nanotech can be be used to create insect sized drones for smaller tasks

protective and lightweight materials

• nanotech can be used to create self healing materials

• nano-containers or intrinsic stuff

Gps

• is a satellite system that provides reliable locations and time of any object anywhere on earth

voice synthesis

• computer-generated audio output that resembles human voice

  • it allows users to concentrate on driving, but consumer a lot of power

robots

• a complex moving machine that is controlled by a microprocessor

applications of robots

1. Car manufacturing

2. Assembling computers

3. underwater maintenance

   1. Toy

Closed circuit television

• is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors

Expert systems

• this is a system programmed with the knowledge from a human expert and it gives reasoned advice in a particular field with explanations f=of its reasoning

components of a expert system

1. The knowledge base; this is the knowledge from the human expert is in the from of if … then rules

2. Inference engine; the code which provides the reasoning mechanism which is used to arrive at a decision

3. User interface; the system by which the user can interact with the system

How to create an expert system

1. Gather info from human experts

2. create the rule/ knowledge base

3. design the inference engine

4. design the user interface

Applications of a expert system

1. Diagnose diseases

2. find symptoms or signs

3. used to help analyse drilling sites

4. used to fault detection with sound techniques

Advantages of a expert system

• provides consistent answers

• never forgets to ask questions

• reduces the time taken to solve a problem

• less skilled force is needed

Disadvantages of an expert system

• lacks common sense in some of the decision making processes

• errors in the knowledge base can lead to incorrect answers

• cannot adapt to changing environments

  • needs considerable training

Benefits of SFX

• Special effects make it possible to combine separate pieces of film and replace part of an image

• explosives, fire and scenes of buildings being destroyed can be made without actually destroying buildings

  • scenes of actors doing dangerous stuff

Uses of vr (again)

1. Hands-on operations

2. Paramedics training

advantages of computer use

• allows access to a wide range of information

• increase in productivity

• allow people to work anywhere

Impact of changing trends

• making learning better

• facilitates easy communication

• entertainment

cons of changing trends

• contributes to poverty

• high criminal acts

• Contributes to health hazards

Evolution of ai and vr

• Cost saving as there is no need for training costs

• Mass production as machines can work 24/7

• help maintain product quality

• Collect data from dangerous

cons of ai and vr

• privacy is a concern

• loss of skills

• loss of employment

Economic effects of computer usage on the environment

• Toxic metals filter into ground water

• when warmed, toxic chemicals

• improper disposal leads to severe risk of identity theft

Printing indiscriminately

• paper waste leads to deforestation

• paper waste leads to pollution

• ink waste leads to soil and water pollution

• ink plastic waste slowly degrades and pollutes soil

data protection legislation

• Be obtained fairly and lawfully

• Be held for the specific purpose and must not be used for any other purpose

• Be relevant and adequate

• not be kept longer than necessary

• kept secure

Causes of system failure

• Software complications; encrypt and backup files

• hardware failure; use parallel systems

• Viruses; install an anti virus

  • Power failure; use and ups

types of computer crime

• Hacking

• Identity theft

• Phishing

• Piracy

• DOS’ing

• Viruses

Methods of preventing computer crime

• Physical security

• Data encryption

• Firewalls

• Install anitvirus

Different security measures

• PIN

• personal unblocking key

• One time password

• Hardware token

• Software token

Uses of spreadsheet

• Calculations using fomulae in accounting

• Forecasting or what if analysis

• Producing graphs for data analysis

Vlookup

• allows a user to pull info from a table, the data must be arranged vertically, with data rows

to use vlookup u need

• lookup_value

• table_array

• column_index

• range_lookup

Hlookup

• like vlookup but horizontally

Date functions

• Today()

• Year()

Database

• is a collection of data items, organized in a way that makes it easy for operations to be performed on the data

flatfile database

• is a type of database that stores every single type of data type on one table

relational database

• is a database with multiple table and they consist of some relationships between them

advantages of databases

• searches can be done easily using queries

• databases minimize data duplication

  • input can be validated

• reduces the need for physical storage

primary key

• a primary key is a special field which makes all records unique from each one

foreign key

• is a field which is a primary key in one table and is also included in another table

Data logging

• the collection of data over a period of time

how data loggers work

• sensors collected the data as analogue signals

• the data is then converted to digital signals with a adc

• data is recorded at regular time intervals

advantages of data logging

• can be used in remote or dangerous areas

• data logging can be carried out 24/7

• time intervals can be frequent and regular

• no need to have a person present

sensors

• Is an electronic component which converts one form of energy to another

Data validation

• checking and making sure they data being entered makes sense in the context it is being used

why binary numbers are used in computera

• computers are digital devices which only recognize on and off, 1 and used to represent on and zero off

register

• is a special location used for temporary storage of addresses, instruction or data during the fetch-decode-execute cycle

why hexadecimal is preferred

• programmers use hexadecimal to present binary code in a human readable form

media control addresses

• refers to a number which uniquely identifies a device on the internet

how is hexadecimal used in code

• makes it easier, faster andless error prone to write code compared to binary

how data flows through computers

• a chipset coordinates the data flow between the system’s hardware components through buses

Buffering

• a buffer is a temporary storage location which stores data that has already been processed by the cpu but is waiting to be used to peripherals

Spooling

• a technique used to speed up communication between devices which operate at different speeds

Cache

• memory integrated into the cpu which can an be accessed faster than RAM

interupts

• stop the execution of the current instruction

• fetch the interrupt instruction from the register

• decode and execute it

• continue with the execution of the suspended instruction

fetch-decode-execute cycle

1. copy address from the program counter to memory address register

2. increment program counter by one

3. copy the instruction from memory data register to current instruction register

4. decode the CIR

5. execute the instruction

6. store results

arithmetic and logic unit

• carries out arithmetic and logic operations

Control unit

• controls the activities of all other parts of the CPU

Memory Buffer register

• the mdr uses the adress from the mar to copy instruction to memory

Memory adress register

• contains the instruction currently being fetched

Instruction register

• copy of the instruction which the cpu is executing at the time

Memory data resgister

• hold instructions and data that are waiting to be executed

Accumulator

• temporarily stores results from the execution

program counter

• holds the address of the next instruction

Musical instrumental digital interface

• contains a list of event that tell an electronic device how to generate a certain sound

check digits

• are numbers appended to an identification number that allow the accuracy of the info to be checked