System analysis and design, development and testing implementation

System analysis and design

A system for upgrading. There is a analysis stage it is for re-review that is to ask customer what they want to change from the preview system to the other. Or adding some touch to the new system. Then there is also design stage, to re-design the data, layout, and many more. 

Verification: to prevent error

Double entry: two people or two electonics or computer

Visual check: for checking errors

Validation: to check wheather if it enters to the system or not

To solve the problem be more simple, system analysis (prelimystudy: problem definition, to make proposal).

Development and testing , implementation

Development

Finalize the file structure

       Type of data

       Length of each field

       Field that will be key field

       How the data files will be linked

4 stages:

       Creating file structure

       Creating validation rules

       Creating input methods

       Creating output formats 

Testing

       Ensure each one functions correctly on its own

       Lead to a need to improve

       Time-consuming process

Different types of testing:

       Normal : 1-12

       Extreme: 1 or 12

       Abnormal: non numeric, coma, negative

Implementation

Changeover methods

1) direct: old system is stopped

Advantage: cost are reduce

                  Less likelyhood of a mal function 

2) parallel running: the old and new system are running side by side for a time before the new system takes over alto.

Advantage: if system fail, there is a back up

                  Staff must set use to the new system

3) plot implementation: new system is introduced into one part of the company and it's performance assessed.

4) phased implementation : initially, only part of the new system is introduced. Only when it proves to satisfactorily is the next part introduced, and so on, until the old system is fully replaced.

 Disadvantage: expensive

Documentation and evaluation

Documentation:

There are two type user and techmical

The way in which ICT is used

Batch processing application

Payroll

Payroll system is used when a company want to pay its employees. It is used to calculate wages and print out slips.

Input:

Employees detail (number of hours work)

The processing:

Gross, pay, any deduction,taxes and national insurance.

Output:

The print slip updating, employing file.

Billing system

Input:

All customer detail, how much payment per month, compare the previous and the new bill.

The processing:

Calculate in 1 row (batch)

Output:

Shows detail and update

Automatic stock control system

Rely in the use of barcode. To see the price, stock value, discount, lot of information about that product.use barcode system, EPOS.go back to data base and be updated. A number underneath the barcode usually consist of 4 part: country code, manufacturer's code, product code and check digit. The check digit form of validation which is used to make sure no errors occurred during the reading of the barcode.

Check digits can be calculate in a number of ways. The method discussed here works for codes wich contain 11 digits

1    3    5    7    9   11      Odd digit positions

5 1 0 4 3 1 1 2 0 1 7

   2    4    6    8   10         Even digit positions

1. Add together the odd digit position and multiply it by 3

        5+0+3+1+0+7: 16

        16 x 3 : 48 

2. Add together the even digit position

       1+4+1+2+1: 9

3. Add the 2 results together

        48+9: 57

4. To find the check digit, calculate what needs to be added to 57 to make the next multiple of 10

        60, so the check digit is 3

Barcode are use for library book system, passport, burglar alarm system, administration system, ID card, stock control system.

Online booking system

Online booking system needs to update files to prevent double booking. For evpxample cinema, theater, aeroplane. For example booking for cinema they must pick a movie-time, date, seat- show up- search data base for available, show seat, price- enter personal information- choose payment- email sent.

Banking application 

ATM ( the replacement of teller, no payment needed)

Insert card-enter PIN-computer check-change PIN, top up mobile, balance, get money- select 1- computer access customer account- customer want receipt or not- card returned.

Disadvantage:

Fake ATM

Place where theft can take place unnotice

Bank charge customer to use ATM

Someone could see our PIN and take all of our money at that bank

Chip and pin

Security

Every restaurant check our money if it is still enough or not to buy or food, bookstore check our PIN. When paying for items using a chip and PIN card, a form of electronic funds transfer take place.

Batch: the payment will be in next month or year, calculate in 1 row

Online: we immidiately pay it right away or straight away. 

Library system

If we borrow books from the library, using library system, we can know when should we return the books. Books that has been returned, been scan by the librarian so that the computer can notice it. To borrow the books, first the librarian should know your identity or personal information. When we want to berrow the books, we should tell our name, contec information, the tittle of the book that we want to borrow, the serial number of the books to the librarian.

Expert system

People want to interview if it's done, it enters the system and data is being transfered. It's been program so if it is done, it should be check once again or test it first. It has it's advantage, have a constant answer, efisien time. And it's disadvantage, the answer is depend on books not peoples logic, usually have error, must be test first.

Control applications

Turtle graphics:

To control of the movement of a 'turtle' on a computer screen. We gave them instructions or commands by typing it. We use this to make a design or a diagram or shape. Here are some of the command that we can type:

🔸forward x : move x cm forward

🔸backward x: move x cm backward

🔸left x: turn left  x degrees

🔸right x: turn right x degrees

🔸repeat x: repeat the drawing x times

🔸unrepeat: finish the repeatition 

🔸pen up: lift the pen up

🔸pen down: lower the pen

Application using sensors:

There are 2 types of sensors, monitoring and control application. 

In monitoring, the computer can only give us signals. For example, if there is a burglar the computer can only beep or give us light signals. They aren't stop if we don't turn the beep or the light signals off. 

In controlling application, the computer proceed or making an action that we firstly already set. For example, in the greenhouse we already set the computer if the temperature of the room is higher than 15 degrees the computer need to open the ventilation or turn on the AC.

Examples of monitoring:

Patient's vital signs in a hospital.

A burglar alarm system.

Environmental monitoring.

Examples of controlling application:

Controlling a greenhouse environtment.

A set of traffic lights. 

Central heating system.

Computer can only read digital data. Sensors, motor, valves and many more can only read analogue data. To connect them, they will need a converter. Analogue to digital converter (ADC) and digital to analogue converter (CAD).

The advantage of using the sensors monitoring:

They cannot forget the readings.

Fast.

24 hours straight.

More accurate.

Safer.

Adventage of using the controlling application:

Faster.

Safer.

If it is dangerous better control it from a distance.

ROBOTICS

Robot are use for manufacturing, heavy work, boring work that repeat their work over and over again.

Robot has a sensor so for example, the robot have a work to spray paint the body of a car, the sensor can read if there is the car or not, so if there is no car the robot will not spray paint. 

Robot is programmed by all instruction that we first set. The operator will control the robot.

Adventage:

Work harmful to human operator

24 hours straight non stop

Less expensive

Disadvantage:

There are some risk for using a robot

Can couse unemployment

Safety aspects

Here is some safety aspects for you to becarefull with your surroundings.

Electrocution:

Don't put your drinks near any gadget, cable, electronics.

Don't overload your socket with many plugs.

You must check the wires regularly.

Cause:

Exposed wires.

To much cable extension in one socket.

To handle:

Turn off the main sources.

Trailing wires:

Risk:

We can be tripped because of the cable that is untidy.

Cause:

Tangled wires.

Prevent:

Cover the wire with rubber and tuck it.

Use the cable duck.

Tucked it away neatly for (example under your desk).

Heavy equipment falling:

Don't put your things in the corner of your upper cupboard.

Make sure there is some gap or space between your things and the edge of the cupboard.

You can also use larger desk or cupboard.

Fire:

Make sure you have some of fire extinguishers each floor of your building.

You have ventilation each room.

Don't overload sockets with too many plugs.

Evacuation roul is needed.

modelling application

Modelling application:
is a simulation that create model. This model is based on mathematical representations. This system can predict the behaviour in the future. A computer models have a advantage that can save up money, safer, also find solution more quickly. There are 2 examples traffic light simulation and model for showing the profit and loss.

Tuck shop simulation:
This simulation can show you the profit and loss of a price. This modelling uses the mathematical form.

Traffic light simulation:
This simulation is more complex. Example of traffic light is a Y junction. The data need to watch traffic for a long period of time at the Y junction.They use sensors to count the number of vehicles that passes through at each junction.This is the following data what do you need to collect:
the number of vehicles passing the junction in all directions
the time of day for the vehicle count
how many vehicles build up at the junction at different times of the day
how vehicle movements change at weekends, bank holidays, etc.
how long it takes a vehicle to clear the junction
how long it takes the slowest vehicle to pass through the junction
the movements made by vehicles (e.g. left turns, right turns, filtering, etc.)
additional environmental factors, such as whether there are pedestrian
    crossings nearby.

Carrying out the simulation:
data from the above list entered to the computer and simulation run. The simulation are compared to the real/ actual traffic light. once the designers are satisfied that it simulates the real situation accurately, then the different scenarios can be tried out. for example:
vary the timing of the lights and see how the traffic flow is affected
build up the number of vehicles stopped at part of the junction and then changethe timing of the lights to see how the traffic flow is affected
increase or decrease traffic flow in all directions
how emergency vehicles affect traffic flow at different times of the day.

Using the simulation:
The simulation can see the flow of the junction, if the red light need to be slower time that it needs, the computer can change the timer as the people control it.
Sensors in the road gather data and count the number of vehicles at the junction.
This data is sent to a control box or to a computer. It may need to be converted
first into a form understood by the computer.
The gathered data is compared to data stored in the system. The stored data is
based on model/simulation predictions which were used to optimise the traffic flow.
The control box or computer ‘decides’ what action needs to be taken.
Signals are sent out to the traffic lights to change their timing if necessary.

Why simulations are used:
to build a real thing need a long time to build but if you use a simulation, you don't need to wait a long time to build it. if you don't like what you are building on your simulation, you just need to delete it.

Batch processing:

A number of task are all collected together over a period of time. Can only be done where there are no timing constraints. Cannot straight away respond. Can be process when the computer is not busy or less busy. Include billing.

Real time processing:

An example of online processing. Booking seats in theatre, flight. Needs to be fast in order to prevent double booking. The booking uses the ATM.

Real time process control:

An example of online processing. Involves sensors and feedback loops. Update in real time. Can see the temperature, data.

Driving simulations:

We use driving simulations for making driving license. Driving simulations used if you cannot drive a car and you want to learn how to drive, usually you use driving simulation car. Driving simulation car is a car if you are driving/ learning, example you ecidentaly want to crush a wall, the car can instantly stop.

Driving simulation use real time process control.

Printer issues

There are many types of printer dot matrix, laser printer, inkjet printer, 3d printer. The usagge of technology can affect our life including our safety. One of the ICT stuff is printer. We can find printers anywhere, at school, at the office, even in our home. Instead of a positif side of printers it also have negative side that are dangerous to us. example of the negativ impact of printers is the uses of toner in laser printer, radiation, EMR, ozone, chemical, and many more. 

Laser printer:

Inkjet printer:

Dot matrix:

3d printer:

Toner is the ink used by laser printers. It's different from the ink found in inkjet printers. Laser toner is made up of a dry, ultrafine powder, and contains a compound called carbon black, which the International Agency for Research on Cancer (IARC) calls a Class 2B carcinogen. The IARC tests show that "sufficient evidence" exists to show that carbon black is carcinogenic to animals, while "inadequate evidence" exists to prove that it's carcinogenic to humans.

The best solution for this problem is put the laser printer in an open, well ventilated.

Some of the printers having noise problem, aspecialy we can find it in old printers or some inkjet printers. Sometimes the noise can disturb us while we are working. It can distract our concentration and bothering our neighbors in the office.  Noise reduction materials such as linen, fabric, or you can move your printer in the separate room with a  good soundproof.

Some printers are potentially can produce ozone (O3) gas above a threshold of tolerable health standards. Ozone (O3) is a highly reactive and unstable form of oxygen. The oxygen we breathe (O2) contains only two oxygen atoms, but the ozone (O3) molecule is made up of three oxygen atoms that are bound together. Ozone (O3), when released through conventional laser copy/print systems, is hazardous to the health of staff. The solutions of this matter are to put the printer in the room with good ventilation or replace the printer with the newest version with non ozone gas.

Good posture in sitting

When you sit, the back of your knees must have space at least 3 finger from the front of the sit pan.

If your feet do not attaches the floor, or you are too short you must use the footrest.

Glasses

If you are wearing glasses, you need to tilt down your monitor 15-35 degree because, to reduces glare and lighting by minimizing the amount of light reflecting off the front and back surfaces of your eye glasses. 

Distance

The distance between you and your monitor should be between 60-90 cm. a good way to see if your monitor is far enough to sit in your neutral position (which the chair pulled in where you would normally sit) and straighten your arm in front  of you. If your hand touches the monitor, you are to close to the monitor.How far you sit from the monitor will depend on your vision, your age and the size and resolution of your monitor. It's the best to sit as far as possible and increase your font size. The distance from your monitor and you should be between 20-40 inches or 60-90cm. A good way to see if your monitor is far enough is to sit in your neutral position (with chair pulled in where you would normally sit) and straighten your arm in front of you. 

Sit a comfortable distance from the monitor where you can easily read all text with your head and torso in an upright posture and your back supported by your chair. Provide adequate desk space between the monitor (table depth) and the user.

Height and location

Working with your head and neck turn to the side for a long prolonged period loads neck  muscle unevenly and increases fatigue and pain. Monitors cannot be farther than 35 degree to the left or right (if your computer position is in front of you). If your monitor is too high you have to work with your head and neck tilted back. You can raise your chair until you can view the monitor without tilting your back. And if your monitor is too low, Monitor should be at or slightly below your eye level, normally it's located 15-20 degrees below your eye level. Downward viewing angle never greater than 60 degrees. 

The position of the monitor must be below your eye level and should be tilted 15 degrees for proper accommodation of your eye. 

Things to do

If you are sitting at a computer at a long periods, you can do these things to avoid injuries:

The maximum time you are sitting and working at your computer Is 2 hours. If you must work more than 2 hours, you can do some stretches shown above and rest your eyes by closing it for 5 minutes. You can go outside and take a walk.