Article: All of these elements are required in every use case. Use cases accumulate scenarios. They define how a user uses a system, what happens when the system succeeds, and what happens when it fails. Each scenario describes a procedure and what happens as each step progresses. Users are all of the people who will engage in the activities described in the use case. For example, if you are writing a use case for logging into a software system, the users would be anyone who must log in. Preconditions are those elements that must be in place prior to the start of the use case. For example, users with permission to use the system have been identified and entered into the system ahead of time, so the system will recognize their usernames and passwords when entered. The basic flow is the procedure the users use to achieve the primary goal of the system and how the system responds to their actions. For example, the user inputs a username and a password, and the system allows the user in. Alternate flows explain less common actions. For example, the user is on a different computer and must answer a security question. Exception flows detail what happens when the user cannot achieve the goal. For example, the user inputs an invalid user name or password. Post conditions are those elements that must be present when the use case is completed. For example, the user can proceed to use the software. Each thing the user does becomes a separate use case. The scope of a use case is narrow. For example, if a company is implementing new software to create purchase orders, you could write several use cases about this. One use case might be about how users log in to the system. Another might be about how to run requisition reports. List all of the functions of the new technology or business process you are analyzing, and write a use case for each one. Outline everything the user does and how the technology or process responds to those actions. In a use case about how users log into a software system, the normal course of events would state that the user enters a username and password. The software responds by verifying the user and either granting or denying access to the system. Alternate flows and exception flows are written to describe the actions when there are obstacles to the goal. If the user is denied access because the system didn't recognize her computer, she may be prompted to verify her identity by answering a security question. If the user inputs an invalid username or password, she may be prompted to answer a security question and enter an e-mail address to receive new log in information. Write use cases for all of the other functions of the software or business process. Identify the users for each function, and write the steps for the normal course of events. Explain contingencies for when the goal cannot be achieved. For each step, explain how the system responds to the actions of the user.
Question: What is a summary of what this article is about?
Define the elements of the use case. Define how the user will use the technology or process. Describe the normal course of events for each use case. Repeat the steps for all other functions and users.
Article: Look at the new belt in comparison to the old one to be sure they are the same width and have the same number of ribs going across the belt horizontally. The old belt may be slightly longer than the new one due to stretching. If the new belt is not the same width as the old one, it is the wrong belt. Make sure the new belt doesn't show any signs of damage from the factory or it may tear after you install it. Run the new belt through the pulleys in exactly the same way the old one was. Refer to the belt diagram in your vehicle's owner's manual or the picture you took of the belt before removing it to guide you. The belt should be long enough to route around all of the pulleys except the tensioner until you relieve the pressure on it. If the belt is loose after routing it, it is either the wrong size belt or you've routed it incorrectly. Use the same wrench to loosen the auto tensioner pulley, then pull the belt over it. Once the belt is in place, release the pressure on the tensioner so it holds the belt in place. It may be difficult to apply pressure to the tensioner and route the belt, so you may want to ask a friend to help. If your vehicle does not have an auto tensioner, insert a pry bar or piece of wood between the alternator and the engine. Run the belt over the alternator pulley, then use the bar to pry the alternator away from the engine and increase the tension on the belt. Tighten the bolts again as you apply tension. You may need help tightening the bolts as you apply pressure to the alternator. Be careful not to pry against anything plastic in your engine bay to avoid breaking anything.
Question: What is a summary of what this article is about?
Compare the new belt to the old one. Route the belt through the pulleys. Apply pressure on the auto tensioner and put the belt over it. Increase the tension on the belt.