Use Cases
Christopher Dole
Professor Jennifer Merritt
CIS210: Systems Analysis and Development
3 February 2013

A use case diagram demonstrates the uses and requirements of a process and its actors. When creating use case diagrams they should be simple and easy to understand so that all levels of outside users can see and understand the roles they have in the overall project (Chen, Slides 6,7). In my first use case we see a use case that addresses the actors and actions for an ATM withdrawal. The use case diagram is simplified and shows how a customer will use an ATM machine to request a withdrawal. It shows the initial interaction in which it is understood the customer will need to enter their ATM Card and provide their PIN to gain access to the account information that is magnetically stored on their card. The high level overview shows a real basic path of the customer requesting a withdrawal and the ATM sending the request to the bank where it receives a confirmation or denial of funds available and then a response is sent to the customer in the form of approval and funds dispersed or a denial. Both will provide a receipt to the customer with the updated balance information or reason for denial. This simple image would be something to provide an Administrator or the like who would be interested simply in the quick path of what is expected. The next UML diagram I included breaks the USE Case into a more specific pattern that shows the events that will take place within the ATM system and the actions required from each actor. This use CASE shows how to ATM customer will insert his or her card and then once validated will request a withdrawal. This would result in the ATM system checking with the bank server to verify and display the balance the customer currently has available. This will then allow the customer to request the funds and the ATM system to send the request to the bank server to verify if funds are available. This would then result in a response based on funds availability acknowledging the availability of funds and sending the request for transaction processing or, if there are fees associated with the request and the bank server indicates fees, the ATM system will display fees to the customer to confirm. If the customer proceeds then the request is sent for processing. In this area the transaction is verified and either approved or denied. Once approved or denied a notification sent to the ATM system results in the customer receiving a notification of denial with a reason or a confirmation that funds are being provided and the ATM system releases the withdrawal amount. This results in the finalization of the transaction through the system confirming the transaction and updating the balances with an ATM system command to print a receipt documenting the transaction and updated balance while providing the funds or documenting the balances and reason for transaction failure. There are other variables that would also be considered with an ATM system for a cash withdrawal including whether the ATM has funds available to fulfill the request and if the ATM has a successful connection to the bank server. These are items that may require a service call for the ATM or cash replenishment. This adds another actor to the picture as well look at the overall ATM server which would be a service technician. The ATM would have its regular service and then the system might notify the bank of service issues and a service call may be scheduled by the bank system. See Below for the Use Case Diagrams created for an ATM withdrawal transaction. The overall ATM system Use Case Diagram is found at the end of this document with a design theory from the web (Hruby, ATM Case Diagram).

The next use case when studying the process for an ATM system is the ATM user accessing their account to make a deposit. As with the previous use case the ATM user will be accessing their account through a magnetic card that has their account details stored to it. They would need to gain access through inputting their PIN security code. Once the account is accessed the system will view and verify the user’s request to deposit funds and determine if the user is depositing cash or check. The system will then transmit this data to the bank server to verify the current balances and which are displayed to the user and what account the user has access to. This will prompt the user to select the account they wish to deposit to and insert the deposit. This will result in a system verification process with the bank server including a count of the cash to be deposited by the ATM and user verification of this count or a transmittal of the image and check details from a scanned check to process this deposit. Next, the system will authorize the transaction and record the amount and type of transaction resulting in the deposit record being displayed for the ATM user and once confirmed by the user a transaction receipt being provided to the user from the ATM system including the account the deposit was made to, the amount of deposit, the type of deposit, any hold times that may be necessary for a check, and the updated balance as well as available balance resulting from the transaction. In this case, there are many variables that could result in different outcomes. These all should be considered for a more detailed transaction. They include weather the transaction is authorized at the ATM. Some ATM systems will not accept a deposit after a certain time or can only accept check deposits. The system would depict this to the ATM user in this event and provide details of when deposits can be made. Also, the system may be unable to read the check deposited and therefor the scanned image will not produce a result to the bank server which would result in a failed transaction as well. This process also could result in certain items that require service to the ATM. It may require that the cash scanner or check imaging tool be serviced if it is not able to read the currency submitted for deposit. The bank may want to consider an alternate envelope deposit system in the event that the scanning deposit system fails. This may require additional considerations to let the user know that they can deposit without an envelope but that this deposit would not be available immediately and the estimated time for the deposit to be manually verified. This may result in prompting the user if they wish to continue and another verification of the change in transaction. Below are the attached ATM Deposit CASE tools.

The ATM System also will have another major use case in which the ATM user may request a transfer of funds between accounts or if offered to another customer. This use case will also begin with our ATM user as the actor gaining access to the ATM system using their magnetic ATM card that has account information stored and providing their valid PIN security code. This would result in the user indicating on the ATM system that they wish to complete a transfer of funds. Once this request is received by the ATM system it will request account balances to be verified through the bank server as well as to verify what transfer options are available for the user. Once the balances and transfer options are verified the ATM system will display this information to the user prompting to verify what type of transfer they would like to complete. This may result in the system requesting the fees for the transfer from the bank server and displaying these fees to the user for verification to proceed. Once the fees are verified, if they apply, or the balance transfer is submitted through the ATM the user will be prompted to select the account to transfer funds from and then where the funds will be sent to. This will then prompt the user to enter the amount they wish to transfer. With the details of the transfer inputted, the ATM System will submit this information to the bank server which will verify the details and send the information to transaction processing. Once the details are sent over the system the processing system will confirm the balance and the requested transfer is authorized and successful. Once the request is processed successfully the ATM will receive a confirmation and confirm with the customer that the transfer has been complete or if there was a failure will indicate the transfer was not successful and the reason. Finally, the ATM system will provide the user the opportunity to receive a printed record of their transaction and produces a receipt of the transfer being complete or the reason for the request failure. This process again may also result in some maintenance requirements in the event that there is a failed connection to the bank system or the server. Below are the attached ATM Use Case diagrams for a transfer request.

Finally, we want to take into consideration several ethical factors in the ATM system including who is allowed to access the data, whose data is being accessed, what actions should be taken to ensure the system is accurate and secure, etc (Relkin). These ethical concerns include major items that have been address within the individual use cases including determining that the ATM user should only have access to the account once a PIN verification code is received. Another that was addressed is the data accuracy in that the ATM system connects to a bank server and each transaction goes through a verification process to ensure the correct balances are displayed, the correct responses are made to each request, and a record of the transaction is provided to the user and recorded by the bank. The system accuracy and security is one that is not addressed. This may require the addition of an ATM security use case analysis as well. In this ethical situation we might look at what actions should be taken to ensure that the ATM system is reading currency correctly and counting currency accurately. It may also require a security system implementation in the bank system to recognize and alert of unusual activity such as large withdrawals or multiple transactions from multiple locations. It may also require a system that will recognize multiple failed PIN attempts and determine the resulting action which may be to retain the card at the ATM system for the customer to pick up at the bank location. These all are important factors in assuring the ATM user has a successful transaction and that his personal and financial information is protected from unauthorized access as well as he or she is not a victim of inaccurate transaction processing from a machine that has not been tested or maintained properly. With the complete ATM system considered I found a great source of an ATM Use Analysis Case online that I have provided a slightly modified version (Hruby, ATM Use Case).

Works Cited 1. Minder Chen. 1994 – 2004. Use Case Tutorial (PowerPoint). Found at: gunston.gmu.edu/ecommerce/sa/ppt/04-UseCaseTutorial1.ppt 2. Relkin, Jeff. 10 Ethical issues raised by IT Capabilities. July 6, 2006. Found at: http://www.techrepublic.com/article/10-ethical-issues-raised-by-it-capabilities/6091121 3. Hruby, Paul. Use Case Diagrams Examples. 2010-2013 uml-diagrams.org. Found at: http://www.uml-diagrams.org/use-case-diagrams-examples.html#atm