Use Case Analysis of ATM

The use case diagrams are graphic expressions that illustrate what a system should do. They enable system analysts to describe possible usage scenarios(use cases) that a system is developed for but do not elaborate any realization details such as algorithms and data structures (Seidl, Scholz, Huemer, & Kappel, 2015).

The application of use case is observed throughout the analysis and design process of a system. They are used to represent the client’s expectation of the system and what they wish to be achieved.  According to Seidel et al, a use case diagram can also be used to document the functionality of an existing system and to record retrospectively which users are permitted to user certain system functionalities.

The following two aspects will be taken into consideration while developing use cases to support the ATM service;

a. the actors and,

b.  the use cases.

The actors comprise those who interact with the system whereas the use cases describe the actions which can be done by the actors.

Withdrawing Money

This case depicts the scenario whereby a bank customer uses the ATM to withdraw money from their own bank account.

Use case

Withdraw

Purpose

Withdrawing a positive amount from an account

Actor

Customer

Input

Withdrawal amount

Output

None

Typical course of withdrawing money

Insert Card.

The case is initiated when the actor (customer) inserts the ATM card into the machine’s card reader. Immediately the system will start a session for the customer which will connect the ATM to the Bank System.

Authenticate Customer. The card reader loads the information from the card and commences customer authentication. The authentication is done by verifying the Personal Identification Number entered by the customer.

Select Withdraw. The customer is presented with a list of services accessible through the ATM machine. The actor proceeds by selecting the withdraw cash option.

Select Amount. The customer is prompted to select the withdrawal amount from the list of typical withdrawal amounts.

Confirmation. The system checks the validity of the transaction. The confirmation is done by querying the bank’s database and affirming that the customer has enough funds to execute the transaction.

Card ejected. The ATM machine ejects the customers card.

Cash dispensed. The ATM machine dispenses the cash. The machine sends a request to the bank’s database to update the customer’s account to reflect the withdrawal transaction.

End.

Alternate course of withdrawing money

Alternate Course 1: Lost or Stolen Card

When validating the card information, if the bank systems communicates that the card has been reported as lost or stolen, the system will seize the card and record a video capturing the customer for five seconds. The system will then notify the bank that a stolen card is being used and also include information about the card details and the video link.

Alternate Course 2: Incorrect PIN

During card information validation, when an incorrect PIN is entered, the system will immediately inform the customer and gives them two more tries. Once the customer makes runs out of granted tries, the system seizes the card and records a video capturing the customer for five seconds. The system then notifies the bank that it seized the customer’s card because the customer failed to enter the correct PIN and sends a copy of the video link.

Alternate Course 3: Unreadable Card

If the system is unable to read the card entered, it records a five second video of the customer. It then notifies the customer that the card could not be read and informs the customer to contact the bank to have the card checked. It finally sends the video link to the bank and any other information that it managed to read form the card.

Account Deposit

This use case covers the scenario of a customer depositing money into their own bank account using an ATM machine. The customer uses an envelope to seal the money and inserts it into the ATM machine. The envelope then remains stored in the machine’s safety deposit box to be verified later on by the bank’s agent.

Use case

Deposit

Purpose

Deposit amount into customer’s account

Actor

Customer

Input

Deposit amount

Output

None

Typical course of depositing money

Customer Identification. The customer inserts the ATM card into the card reader and proceeds with authentication.

 Select Deposit Money option. From the list of options displayed on the ATM, the customer chooses the ‘Deposit Money’ option.

Enter Account number. The customer is prompted to enter the account number where the money is to be deposited.

Amount. The actor enters the amount to deposit.

Deposit. The customer is prompted to put all the money in an envelope, seal the envelope and insert it inside the safety deposit box. The ATM prints the transaction ID on the envelope and stores it inside the safety deposit box.

Verification. The bank is notified about the deposit and proceeds to verify the transaction.

Receipt generation. The customer is issued a receipt containing details about the transaction.

Card Ejected. The card is ejected to the customer.

End.

Account Transfer

This use case covers the scenario of a customer transferring money form their own account to a different account. The customer enters the recipients account number and specifies how much should be sent. Once the system approves the request, the recipients account is credited with the amount.

Use case

Transfer

Purpose

Transferring money from one account to another

Actor

Customer

Input

Recipient’s account number, Amount to be transferred

Output

None

Typical course of account transfer

Customer log in. The actor/customer logs into the system using the card issued by the bank.

Select Transfer Money option. From the list of options displayed on the ATM, the customer chooses the ‘Transfer Money’ option.

Enter Account number. The customer is prompted to enter the destination account number which will be credited with the transfer amount.

Amount. The actor enters the amount to transfer.

Verification. The customer request is verified by the system. The system checks if the customer has enough funds in the account to cover the transfer and also verifies existence of the destination account.

Validation. If the request is successfully verified, the customer’s balance is deducted with the transfer amount and the recipients account is immediately credited with the same amount.

Accounting. The transaction log is sent to the bank’s database.

Card Ejected. The card is ejected from the ATM.

End.

Ethical issues exposed in the use case

One major issues that keeps reappearing in most use case is attempted theft. The ATM machine has predominantly relied on the use of video footage to record suspected perpetrators of theft. Whenever an possible theft scenario is detected, the machine has in built capabilities that immediately try to prevent the fruition of the theft and also try to gather video evidence of the actor.

References

Seidl, M., Scholz, M., Huemer, C., & Kappel, G. (2015). UML @ Classroom: An Introduction to Object-Oriented Modeling. Springer.