Software Engineering - Tutorial 3

A smart lock is an electromechanical lock which is designed to perform locking and unlocking operations on a door when it receives such instructions from an authorized device using a wireless protocol and a cryptographic key to execute the authorization process. It also monitors access and sends alerts for the different events it monitors and some other critical events related to the status of the device. Smart locks can be considered part of a smart home. [Source: wikipedia]

We consider three systems: a smart phone application, a smart lock embedded software, and the smart home platform.

The actors of a car repair and maintenance business include:

We consider the following use case subjects for this business:

Draw the activity diagram for the normal story where the car owner discusses with the service advisor what needs to be done on his car, then the repair plan is validated in the repair and maintenance IT system, the car enters the workshop, the stock management system gets informed of the needed parts, the parts counter person brings the needed parts to the technician and updates the system, the technician works on the car, then the clients pays the service to the service advisor and gets his car back.

Draw an activity diagram to model the normal usage of the sleep apnea treatment device, including: levels monitoring and visualization; operating with different pressure level; decisions that the doctor and the patient may make; update to the program, etc. Draw swimlanes for the activities of the different actors.

What happens if the air stops flowing suddently? Add an interrupting edge if appropriate.

Below is an slightly modified description of the JPA entities lifecycle. Identify the states and state transitions, and complete the UML state machine diagram to summarize the following specification:

After being initially created (with the keyword new), an entity object is not yet associated with an EntityManager and has no representation in the database. So their state is lost and garbage-collected as soon as they are no longer referenced.

Invoking a persist operation over an entity object creates a view for that object in the database. This operation can be cancelled using a rollback operation. Else, any change made to such an entity is going to be detected and propagated to the database. The refresh operation updates the entity object according the the latest state in the database.

After a commit operation, or when the current running Persistence Context is closed, successive changes will no longer be tracked and no automatic database synchronization is going to happen. Synchronization can start again after a merge operation.

An entity object in sync can be scheduled for deletion with the remove operation. The actual database DELETE statement will be executed after a commit, then the entity object becomes transient again. This can be cancelled with the persist operation.

Students enrolled in the Machine Learning course need to learn, then prepare their case study (CS) and prepare for the written exam (WE) in parallel. The course is validate if the mark (CS+2WE)/3 is above 10/20. If the student is within the best 10% of his class, the grade is A. If the student is within the next 20% of his class, the grade is B. If the grade is above 10/20 but the previous conditions are not met, the grade is C. If the grade is between 7/20 and 10/20, the student has the choice to pass a retake and get a D if validated, or to get a F (fail), and potentially enrol for the course the next year.

Identify the states and state transitions, and write the UML state machine diagram to specify the rules of the course.

Look at the class and object diagrams below, and correct the object diagram if necessary.

Draw different class diagrams with association and multiplicities for modeling graphs, with nodes and arcs that link nodes.

Draw a class diagram for describing the following situation:

The game has a set of ships with a name, position, status (standing_by, navigating, touched, sank). Ships may be created in different ways. Ships may be requested to move at a certain speed, game default speed is 1, in direction of another position. There are moored and drifting mines. Mines may be added or removed to the map. The game, and ships, have an operation next that computes the positions and statuses of the ships and drifting mines for the next iteration of the game. The main class contains an operation shoot. This operation may fail or succeed, depending if there is a ship at the given position.

Below is a cheat-sheet for the JSON file format, and an example JSON document.

We consider two IT systems for this business:

We want to design the IT systems that model the following settings.

Identify the classes and separate them in packages, such that each IT system uses the minimal number of classes.

Several classes presented in the figure below have attributes which are actually pointers to other classes. These pointers could be replaced by associations between classes. Modify the class diagram accordingly and also take into account the following information:

A student undertakes examinations for different subjects. For each test, he receives a score. Finally, according to his results, he receives a diploma with a mention. He is also assigned to a single room. The class diagram in the figure below represents this description. Class Work describes the subject of the examination; the solution provided by the student is not stored in the information system.

Comment and compare the advantages and disadvantages of the two approaches illustrated in the figures below (inheritance vs. delegation). To support your point, use the specific case of creating a Dog object. We may also consider changes in regime.

Concerning the figures below:

A gardener does two types of jobs: watering and hoeing. The former consists in watering the plants (tulips, geraniums or eucalyptus) with a tool (watering can or hose) containing water and the latter consists in turning the soil with a tool (spade or shovel) to put in the fertilizer. In other words, the gardener uses a tool (watering can, hose, shovel or spade) to bring a resource (water or fertilizer) on a natural object (land or plants); it is produced by a work activity (spraying or hoeing).

To model booking flights for a travel agency, interviews with business experts produced the following sentences:

Build the class diagram from the knowledge expressed above.

Write a class diagram to represent the expressions with binary operators, and the object diagram for the following expression: (X + Y / 2) / (X / 3 + Y).

Parentheses are shown here for associativity reasons, but should not appear in the diagram. Update the class diagram in order to take into account unary operators.

In a company, two types of parts are considered: the basic parts that are purchased from outside, and composite parts, which are obtained by the assembly of other parts (composite or basic).

We want to build an information system to manage all these pieces unitarily. We store information like the names of the parts, cost of assembling a composite part, and the list of parts used in its building. For each basic part, we store its name and its unit price.

Draw the class model satisfying all these requirements.

Prepare a class diagram for the problem of dining philosophers. Five philosophers are around a circular table on which are placed 5 forks. Each philosopher has access to two forks on each side of his plate. Each fork is shared by two philosophers. Each fork can either be on the table or used by one of the philosophers. A philosopher must have two forks to eat.

In human society, the laws regulating relations between individuals (men, women, children …​) are the following:

Express in a sequence diagram how a map-less automated vacuum cleaner operates in a room with obstacles and rugs. The vacuum cleaner needs to rise the suction power when on a rug.

Describe the state diagram of the class whose behavior is described below.

Correct the sequence diagram below to conform to the state diagrams of classes Sender and Receiver.

A cash register operates as follows:

Build some sequence diagrams representing the operating scenarios of the cash register (at least one case weight article sale and another for the case unit article sale). Make your assumptions clear. Construct the state diagram for class CashRegister.

A computer system is required to control fuel flow, manage the payment from customers and control the level of fuel tanks of a petrol station. This service station has 3 pumps, one for each grade of gasoline available (regular, medium and super).

A customer who wishes to obtain supplies of gasoline goes at the pump of the appropriate category, presses a button to have permission to use the pump. Alerted by a beep on his terminal, the employee provides service authorization from its terminal and the pump motor turns on. The customer enters the amount he wants to be equivalent in essence, leaves the nozzle from his holster, and pulls its trigger; gas begins to flow.

A conveying system for coal includes a trolley moving on a rail, and transporting coal from a loading area to an unloading area. The loading of coal at the loading area is carried by a crane. A set of sensors are positioned on such equipment and emit a set of events (in the rest of the problem we will consider that these events other than those issued by the crane and trolley are issued by an entity called Controller). Two classes can represent this problem: Trolley and Crane.

Prepare a UML class diagram for a graphic editor. The attributes of classes are not required.

The documents handled by the editor are composed of layers. Each layer contains graphic objects, including text, geometric objects and groups. A group is simply a set of graphical objects, including possibly other groups. A group must contain at least two graphic objects. A graphic object may be a direct member of only one group. Geometric objects include circles, ellipses, rectangles. lines and squares.

Consider the software that controls a very simple cellular telephone. Such a phone has buttons for dialing digits, and a send'' button for initiating a call. It has dialer'' hardware and software that gathers the digits to be dialed and emits the appropriate tones. It has a cellular radio that deals with the connection to the cellular network. It has a microphone, a speaker, and a display.

Let us look at the way the phone works. To keep things simple, we just consider how a customer might make a phone call.

The use case for this interaction looks like this:

Draw the communication diagram corresponding to this use case.

A watch with digital display has two buttons A and B and two modes of operation: {"}Display Time{"} and {"}Update Time{"}. In {"}Display Time{"} mode, hours and minutes are displayed. Mode {"}Update Time{"} has two sub{}-modes: {"}Update hours{"} and {"}Update minutes{"}.

The direction control for the first electric trains toys are made by interrupting the supply of the train. Prepare a state diagram for the front lights and the wheels corresponding to the following scenario:

The state diagram shown in figure below is the state diagram of a telephone line which we have seen usage scenarios in the course.

Company C manufactures metal parts made in his workshop. Company C has only business relationship with regular customers. Invoices are paid monthly: all orders from a customer in the month are billed at the end of the month. Upon receipt of an order, the secretariat of Company C produces a \ manufacturing coupon and transmits it to the workshop (a duplicate of the manufacturing coupon is sent to the client). Once the part is manufactured, the workshop complements the manufacturing coupon and transmits to the Secretariat who records the end date of manufacture and inform the customer that his order is available at the workshop.

Hypothesis: We believe that all payments are correct: a client pays the total invoice or it does pay.

Out of scope: registration of new client is out of the scope.