## 7 Scientific Issues and Deployment Implementation Routes
### The Scientific Issues  
According to the three key points, three scientific issues that to be solved are summarized.  
1. Scientific Issue 1: Complex game relationship of networked ATM-CPS. This scientific issue aims to solve the first key point--finding the security threats faced by the aviation network and studying the source and extent of threats to aviation network security. Networked ATM system is a multi-dimensional complex system integrating network, computing, and equipment physical environment. Through the organic combination and deep cooperation of aviation communication, statistical calculation, and automatic control technology, it faces the management and control challenges of soaring flight density and diversified types of aircraft and realizes the safe and efficient operation of air transportation. Therefore, the networked ATM system is a complex intelligent management system with CPS characteristics, which is a deep integration of cyber system and physical system. Therefore, solving the CPS model of the networked ATM system is beneficial to: * Master the security threats and degrees faced by the networked ATM, and build a unified and effective threat model; * Analyze the requirements of information security assurance of ATM system, design the technology of information security assurance of ATM system, and build a systematic information security assurance architecture of ATM system. 2. Scientific Issue 2: Networked ATM-CPS information security situation awareness. This scientific issue aims to solve the second key point--to master the security status of aviation network operation. According to the operation of the networked ATM system, the prediction and evaluation of its network security situation will help to timely adjust its information security assurance strategies and measures. It includes two processes: * Security situation prediction. The change of security situation of networked ATM system is a complex nonlinear process. An intelligent prediction model based on neural network is established by using deep learning method. Nonlinear time series prediction is conducted for time-based sequence actions in ATM operation. The depth neural network model is used to calculate the nonlinear time series data, and the security situation of the networked ATM system is obtained through approximation and fitting; * Security assessment. According to the requirements of the National Security Classification Protection Guide, an approach based on security baseline strategy is adopted to conduct a multi-dimensional security assessment of the networked ATM system from three dimensions: static (functional design and technical measures), dynamic (operation status and development trend), and status (security status and security attributes). 3. Scientific Issue 3: Systematic ATM-CPS information security assurance mechanism. This scientific issue aims to solve the third key point--building a complete aviation network information security assurance system and establishing a lasting and effective security mechanism. It is necessary to establish the security threat model of the networked ATM system and propose a complete network security defense solution for the networked ATM system according to the SSE theory. It includes: * Analyzing the characteristics of the ATM system and the demand for information security assurance, formulating the information security assurance strategy of the ATM system, launching the ATM-CPS information security assurance plan, and building a systematic information security assurance architecture of the ATM system; * Specifying the requirements, guidelines, and specifications for ATM-CPS information security assurance and designing specific core algorithms, special methods, and key technologies for information security assurance.