# An Improved FFIP Method Based on Mathematical Logic and SysML
## 4 Improvement of SysML Based on Failure Logic  
### Conversion Method from FFIP to SysML  
In this paper, we combine the FFIP method with SysML and use different graphs of SysML to demonstrate the FFIP model. Using SysML to represent the structure and function model of FFIP can make the information flow and function flow more closely related. Additionally, the use of SysML can facilitate communication and make design easier between system users, maintenance personnel, and those who may debug, integrate, extend, modify and change the system [46]. SysML is mainly composed of nine types of diagrams: activity diagrams, sequence diagrams, state machine diagrams, use case diagrams, requirement diagrams, block definition diagrams, internal block diagrams, parameter diagrams and package diagrams [47]. The mapping relationship between FFIP and SysML elements is shown in Table 3.  
The block definition diagrams (BDD) in SysML define the attributes of modules and the relationships among them, which includes association, generalization, and dependency. The block attributes of BDD can be divided into two types: structure attributes and behavior attributes. The value attribute of a structure attribute can be used to represent the output signal and flow value of the module. Moreover, the operation attribute of the behavior attribute can be used to represent the functional behavior of the module. Therefore, we can use BDD to describe the structure and function model of FFIP. In this way, the structure model and function model of FFIP can be represented in the same BDD of SysML. The advantage of using BDD is that the structure, function, and data flow can be  
Figure 2: Failure logic diagram.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**FFIP Elements** & **SysML Elements** & **SysML Symbol** & **Explanation of Meaning** \\ \hline Component & Block & \(\star\)Block\(\star\) & It represents the events in the process dimension and the people, machines, and environment in the object dimension. \\ Information & Attributes & \(\star\)valueTypes & It describes events, as well as the value attributes of people, machines, and environments. \\ Function & Operation & \(\star\)valueTypes & It describes events, as well as the functional attributes of people, machines, and environments. \\ Behavior & Message & It describes the relationship between basic events and people, machines, and environment factors. \\ Reply & Reply message & It describes the feedback of behavior. \\ Structure connection & Directed Association & It describes the relationship between the events and their processes. \\ State transfer & Transition & It describes the transition conditions between different states. \\ \hline \hline \end{tabular}
\end{table}
Table 3: Mapping relationship between FFIP elements and SysML elements.  
expressed at the same time, which makes the functional design of components clearer and easier to communicate and modify by different users.  
Sequence diagrams (SD) in SysML can describe the sequence of actions and information flow transmission. There are two advantages of using sequence diagrams. They can describe the behavior rules in the behavior models of FFIP and can also describe the information transfer relationship between modules. Using the SD of SysML presents the complex task process in a more organized way, which makes up for the disadvantages of using tables to list behavior rules in the FFIP method.