Defining Structural Representation

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The structural representation forms part in the logical solution formulation of the desired system. It’s describes the system from a static perspective (modularity and hierarchy). This representation is constructed by defining the subsystems (or components) in which the system can be divided and the connections between them.

Structure and Hierarchy

A block definition diagram (bdd) is used to represent the structure and hierarchy of the system, by dividing it in a set of subsystems or components. Inside this diagram is added each subsystem as a block element of SysML and the hierarchy is defined by establishing containment relations, composite association connection of SysML.

In the bdd is added each subsystem as a block element of SysML and the hierarchy is defined by establishing containment relations.

For the case SHRM system only the remote subsystem is modeled. In the BDD created in the item 1, is started with block named SHRMSRemote which contains the following components:

1. Capture: Component responsible in capture the information from the sensors and the energy of the power grid.

2. Acquisition: Component responsible in management and process the captured data.

3. Encode: Component responsible in the encryption of the data send to local system.

4. Visualize: Component responsible in show the captured information.

5. Communication: Component responsible in send the data to local system.

6. BackupPower: Component responsible in power the system when the power grid doesn’t work.

7. SelectEnergy: Component responsible in select the energy source for power the system.

The figure 1 presents the architecture of the System SHRMS.

shrms bdd shrmsremote

Subsystem Connections

To complete the structural model of a system, the information of the connections between the environment and the system, and between subsystems must be modeled. An Internal Block Diagram (ibd) is used to define the required ports and connections. The ports are represented for Flow Port whiles the connections for Connector, which are elements of SysML. The part elements are created automatically, given the composite association defined in the bdd and represent the internal blocks of the parent block.

For each components of the SHRMS system is defined an ibd diagram.

To create an ibd to the Acquisition block, right click the block in the outline view and add a new internal block diagram (Add diagram Internal Block Diagram); or click double on the block and select the option internal block diagram. The parts energyAcquisition, sensorAcquisition, visualizeAcquisition and comunicationAcquisition are added to the ibd drag them from the outline view. The visualizeAcquisition represent the VISUALIZEacquisition block. It’s connected to Acquisition, VISUALIZEacquisition and comunicationAcquisition blocks via the flow ports sensorAcquisition_acc_measure and sensorAcquisition_acc_digital.

When is added a Flow Port is prompted to select a type to reference from port. If the port is being added for the first time choose Create a new Block to reference from the Port, otherwise, select Choose an existing Type to reference from the Port and select the appropriated block.

After adding the required ports inside ibd of Acquisition block, is define the connections between the gotten the diagram that is illustrated in the figure 2.

shrms ibd acquisition

Note. Two considerations must be taken when adding Flow Ports.

  • Naming. Alth ough any name can be used, we recommend to follow the component name_ port name convention (i.e. sensorAcquisition_acc_measure). First, the component name will allow distinction of ports with the same name in different components and second, while creating cross references it makes it easier to search for specific ports.

  • Nesting. The TopCased editor will place the new block at the same level in the outline tree as the block to which the ibd belongs, i.e. a block created as a result of adding a Flow Port to the ibd of the SHRMSRemote block will be at the same level as the SHRMSRemote block, regardless if the Flow Port was added to the SHRMSRemote or to one of the internal components. We recommend that you move the blocks in order to place them as children of the block their respective ports belongs to, i.e. at the same level as their respective port.