# A Modeling Method of Agents and SOA in Advanced Avionics System Based on AADL
## 1 Introduction  
With the advancement of aviation technology, artificial intelligence and information technology have become the focus of aviation research. [PERSON], academician of Chinese Academy of Sciences, and [PERSON], academician of Chinese Academy of Engineering, highlighted the importance of information and intelligence technologies in their discussions on the development of future fighter jets [1; 2]. As an indispensable part of information, software architecture is the important foundation of avionics systems and artificial intelligence technology in avionics systems. The application of artificial intelligence technology and service-oriented architecture (SOA) in avionics systems has become the focus of avionics architecture. Expert systems that contain intelligent agents have been applied to improve the reliability and maintainability of avionics systems [3]. A new generation of airborne human-computer interaction systems has been developed based on multi-agent systems to enhance situation awareness and decision-making through the pilot cockpit [4]. Furthermore, recent studies have revealed that the SOA can help an avionics system not only improve its flexibility but also reduce the cost and human-computer interaction of updating features [5; 6; 7]. Likewise, the SOA has been applied to avionics systems [8; 9; 10; 11; 12]. However, with the increase in the scale of avionics systems, system design becomes increasingly complex; thus, modeling has become the focus of design work. Improvement of the modeling method of agents and SOA is the focus of current research. This paper proposed a novel modeling method of agents and SOA in avionics systems. Agents in avionics systems can interact with the external environment autonomously. When the input changes, the working state of the agent will also change, and many attributes of the agent will also change under these states. In addition, SOA encapsulates functional units as services, and deploys and reuses them, which brings higher flexibility of software architecture and convenience of development. However, when SOA executes different applications, the difference of services invoked will lead to the change in system attributes. Such changes in the attributes of agents and SOA will bring difficulties in describing many of their characteristics, such as the task time delay, task reliability, processor scheduling policy, and so on. Traditional avionics system modeling methods lack accurate description of these changes and characteristics of agents and SOA; such inaccuracies in modeling will bring great difficulties to the analysis and design of the system, which may lead to software system failures and even serious accidents and dangers. As an integrated system of software and hardware, the modeling method of avionics system needs to consider the modeling of integrated systems of software and hardware. Architecture analysis and design language (AADL), a representation method, is developed for designing and analyzing software and hardware architecture of an embedded real time system and its functional and non-functional properties [13; 14; 15]. This modeling language mainly focuses on the binding relationship and interaction between system components, and adequately describes the complex real time embedded system architecture. However, there are some issues to consider in the modeling work. First, the working state of the agent changes with the input and SOA is characterized by architectural flexibility and not only the encapsulation but also reuse of functions. These require a modeling method to effectively support the dynamic behavior of the system. Secondly, AADL language is suitable for modeling avionics systems, but the model of software architecture in existing avionics system modeling methods lacks dynamic behavior description. The mode component in AADL is suitable for describing dynamic behavior.