# A Modeling Method of Agents and SOA in Advanced Avionics System Based on AADL
## 4 Case Study  
Based on a case study of some functions in an avionics system, modeling of advanced avionics architecture, including agents and SOA, is completed. The model is divided into the following three levels: front-end radar module, signal processing module and application module. With the hierarchical distribution, the modeling method of \"signal-data-knowledge\" is adopted. In the working process, the front-end radar module detects the target signal, and the signal processing module processes the radar signal to obtain data. The application module analyzes and processes the data to obtain knowledge, which is used in the follow-up work, such as path planning, communication and equipment monitoring. The front-end radar module contains two radar modules. The radar module contains the radar detection equipment, FPGA module and switch. The device component represents the radar detection equipment and switch, and the processor component represents the FPGA module. Signal processing module includes the signal processor, FPGA module, power supply and data storage module. The device component represents the power supply, processor component FPGA module and signal processor, and memory component data storage module. The application module contains multiple software components, such as the Data Distribution Service (DDS), Remote Procedure Call (RPC) component and SOA System. The SOA system includes intelligent path planning, communication and equipment health status monitoring and related services. The SOA system is represented by the system component and the DDS and RPC component are represented by the process component. The graphical model of the three-level architecture of the avionics system is shown in Figure 6. Moreover, in Figure 6, the green part represents the signal level, the red part represents the data level and the yellow part represents the knowledge level. These three parts together form the three-level architecture. In the SOA system, there are three applications, including intelligent path planning, communication and equipment health monitoring, and five services, including the path  
Figure 6: AADL model of avionics three-level architecture. planning service, communication management service, signal reception service, signal transmission service, equipment signal acquisition service and equipment status analysis service. The mapping between application and service is as follows: intelligent path planning application includes the intelligent path planning service, signal reception service, and signal transmission service. Communication application includes the communication management service, signal reception service and signal transmission service. Equipment health monitoring application includes the equipment signal collection service and equipment status analysis service. The path planning service includes an agent, and the agent modeling method is used to model the service. According to the characteristics of the agents, its state is divided into the following three states: target recognition, obstacle warning and path planning. The agent service has different execution time attributes in the three states, and its state transition is triggered by different image data input. This system is modeled using the SOA modeling method in this article. The system component is used to describe the intelligent path planning, communication and device health monitoring in the system, and the process component is used to describe the services contained in the application. The application transition of the system is triggered by task request events. For intelligent path planning services that contain agents, process components are used to describe them. A graphical model of the SOA system is shown in Figure 7. In Figure 7, the colors red, yellow and green are used to represent three different applications, including intelligent path planning, communication and equipment health monitoring.