Systems Analysis And Design: Use Case Diagrams For The Smart Home

Discuss about the Systems Analysis and Design, He will be able to see all the times that have been configured for the alarm to ring. They can also add more alarms or delete existing ones.

Use Case Diagrams for the Smart Home

Use Case Diagrams are referred to be behavioral diagrams by many system designers worldwide. SOS needs to provide simple diagrams that help to describe a set of actions mostly known as Use Cases. They can also show how a system should perform by its own and by collaborating with other external actors. Different people may come up with different system design case diagrams but the best is always utilized when implementing the system.  Just so as to be competitive in its processes of design and installation, SOS Smart Home assigned her designers the same roles of designing Use Case diagrams that can be used as guidance in implementing the design of their smart home systems.

The initial and most simple use case diagram was the one on fig 1.0. This use case simply gives a visual representation of how the owner works on the various devices in his/her smart home. Any time they want to use an appliance, they have to provide their username and password. There is a great need for access and identity management as it keeps away unauthorized persons from accessing the appliances at the home. An outsider should not at any time have the luxury of using the smart home devices just like they want. This will help the owner keep his appliances safe from physical harm. This will bring down the costs of maintenance. When someone provides a wrong pin, they will not be allowed to proceed with using the appliances. From fig 1.0, Reading mode describes the process with which the owner views the list of all appliances in his home. He then selects on one, for instance, the smart alarm. He will be able to see all the times that have been configured for the alarm to ring. They can also add more alarms or delete existing ones.

The initial diagram in fig 1.0 does not show all the use cases clearly. The designers had to design yet a new use case that was more detailed as it has been shown on figure 1.2. After the home owner has turned on the devices at his home and has been authenticated to use the smart home appliances, they will then view a list of all the devices and observe their statuses. All these can be done using an android or IOS smart phone. The SOS smart home designers in the middle of the design process realized that so as to be seen as very valuable to clients, they had to come up with a complementary system that assists the home owners to control their homes just by using a smart phone. There are many other technology companies that provide smart home design and installation services. To be on top of these companies, SOS smart home had to develop the app as fast as they could.

When the home owner is at home, and he forgot some food cooking in the kitchen, the food may cook until it burns producing smoke. The smart smoke alarm will detect this and immediately sound an alert alarm to the owner. The use case in fig 1.2 gives this impression clearly.

Activity Diagrams for the Smart Home

More improvements on the design of use case diagrams for the smart home were continuously made. The above figure 1.3 adds a couple of more other use cases into the previous diagram. The smart door sensor was not indicated in fig 1.2. The user now after viewing the list of devices and their statuses, he or she will have to activate or turn on the smart door sensor. Once the sensor is on, it will send a signal to the smart alarm anytime a visitor is on the door.

The above fig 1.4 is yet another design improvement made by the design team. You can note here that the designers realized a small problem they made in the earlier designs. All the use cases they made had no direct relationships which are usually shown by “<<include>>” symbol. It is now clear on fig 1.4 that you must turn on the devices then you login so that you can have full access to the devices. All the step by step procedures are now clear.

All the use case diagrams from fig 1.0 to 1.4 did not visualize all the smart devices that are installable at the home. The designers addressed this issue by coming up with a final use case diagram. This is the best diagram that they finally agreed to utilize during implementation.  The Smart smoke alarm, the smart detector of heat, smart door sensor, the fan, and the detector of heat and humidity are seen in this final design. It is noted that all the devices are managed by just one single user who is the owner of the home.

This is the initial design of the activity diagram. After the initial node, the server is initialized. This is a crucial step for a majority the smart home appliances since they are connected to a central database. The server in this diagram represents the local MYSQL database. The databases in the cloud are assumed to be live since they are always online. The GSM module is then initialized to ensure that there is internet connectivity. The devices will search the internet for any patch updates and system updates. They will also retrieve data from the local database containing information of the current state of the home and then give an update to the user’s smart phone. On receiving the current state of the home, the owner will acknowledge the information and then take appropriate steps or just leave everything as they are if normal. Through the internet connection, available at home from the Wi-Fi network, the owner is able to receive updates wherever they are outside their home.

The design team again had to do some improvements on the activity diagram that was used to implement their Smart home systems previously.  Fig 1.7 is an improved version that has addressed problems found in the past activity diagram. Among the concerns addressed were: The owner has to initialize the server and internet connection before logging in to the system. This change in the flow of processes aids in the smooth operation of the system. A user cannot logically login or be authenticated into a system whose database is not online. When the local database and the internet is brought up firing good, the user will be able to login faster with no complications. This activity diagram ensures that a user cannot access the smart home appliances before he is first authenticated.

Class Diagrams for the Smart Home

A class diagram is utilized to describe all the operations of a class and all the constraints that are imposed on a system (Baudry, 2002). The proposed SOS smart home system would be developed utilizing object oriented methods in the programming language used. Class diagrams are mostly implemented on object-oriented information systems. This is mainly because they are the only UML diagrams that can be linked directly with object oriented languages. For these reasons, the recommended language would be java.

The proposed system will have several classes in its final design. The classes will include Owner/Manager, Login, selectAppliance, update, smokeAlarm, securityAlarm, and detect. These classes represent different non-functional requirements of the proposed system. The Owner class is the class which contains functions that request the database for registered user information. This class also allows for the creation of new owner accounts for the home appliances systems. During authentication, it is the owner class that verifies the identity of any person intending to access and manage the home devices using a smart phone. The selectAppliance class handles the requests by the user when they choose a device they want to manage on the interface. It also definitely allows the owner to view the available devices and which ones they need to physically turn them on. The update class works on updating the local and cloud databases real facts about the home. These are the humidity of the home, smoke, and even the number of times the alarm has rung.

The aforementioned classes do not function independently, every other class depends on another (Baudry, 2002). For instance, the selectAppliance class cannot run when the login class has not rightly authenticated a user. The securityAlarm class must talk to the detect class so as to know when to ring and when not to ring.

The smart door sensor sends notifications to the user’s smart phone whenever it detects that someone is on the door. The designers came up with a very simple use case diagram having just only two use cases: the smart phone and the smart door sensor. Both use cases are connected to an entity named system. The entity named system here contains the local MYSQL database that is hosting most of the smart home system data set. The system also contains the cloud technologies which in this case help update the owner even when he is out of his Wi-Fi network coverage (Berman et al., 2012). This use case is so simple to bring ease the people implementing it might be a different software solutions company.

This diagram (fig 2.1) explains the flow of activities during the working of the smart detector of heat and humidity appliance. After the system is initialized, it immediately checks on the humidity of the surrounding and sends the response to the owner’s smart phone.

State machine diagram showing the classes used by the smoke detector and the door sensor sub devices. The smart appliances must at the beginning be turned ON. Afterwards, if they are switched OFF, they will shut down and return to an offline state. Else, the smoke detector will be ready to detect any smoke in the home and alert the owner. The smart door sensor works again in a similar manner as shown in the state machine diagram. If it does not detect any intruder in the home surrounding, it just exits and does not alert the owner. In case an intruder is found, through the decision node, an alert is then sent to the home owner’s mart phone.

The smart alarm is turned ON and the user is shown a smart interface for setting the alarm they want. Be it allowing it to ring when the house temperature goes over 20 degrees centigrade. After all, has been set, the user exits leaving the alarm ON.

An entity relationship diagram illustrates the relationships of entity sets that are stored in a database (Cagiltay, 2013). The components of data in this proposed system as shown in Fig 2.5 include the owner, Appliances, and operations. The owner entity contains attributes such as the name of owner, password and mobile number. The appliance entity consists of the appliance name and its random code.

The SOS Smart Home Designers had to spend more of their time coming up with all the diagrams to ensure that they remain relevant in a very competitive business. The diagrams designed will be easily understood by any new team that is tasked with the installation of the smart home system appliances.

Baudry, B., Le Traon, Y. and Sunyé, G., 2002. Testability analysis of a UML class diagram. In Software Metrics, 2002. Proceedings. Eighth IEEE Symposium on (pp. 54-63). IEEE.

Berman, S. J., Kesterson-Townes, L., Marshall, A., & Srivathsa, R. (2012). How cloud computing enables process and business model innovation. Strategy & Leadership, 40(4), 27-35.

Cagiltay, N.E., Tokdemir, G., Kilic, O. and Topalli, D., 2013. Performing and analyzing non-formal inspections of entity relationship diagram (ERD). Journal of Systems and Software, 86(8), pp.2184-2195.