The networked air and missile defense system has the ability to flexibly control combat resources， effectively realize dynamic cross-domain command and control， and efficiently complete combat tasks. However， networked and integrated operations increase the risk of weapon systems suffering from cyber attacks while improving combat effectiveness， which will seriously threaten network security and combat effectiveness of combat equipment. Taking the U.S. tactical-level air and missile defense system as an example， according to its networked combat characteristics， this paper analyzes the security vulnerabilities of the air and missile defense network， and constructs an assessment model to analyze the probabilities of destroying network nodes. Three indicators are designed and used to evaluate the network performance loss of the node suffered network attack. The OPNET platformand the NetworkX are used to carry out network simulation experiments. Based on the evaluation results， the network defense strategies are proposed to provide reference for the improvement of the security defense capability.

Regarded as one of the “game-changing” cutting-edge technologies by the main powers， artificial intelligence （AI） is expected to improve the reliability， rapidity， and autonomy of space equipment and exert a disruptive impact. In this study， the development state of AI and its applications in space equipment are briefly analyzed. Then， the application architecture of AI in space equipment is established. On this basis， the application scenes of AI in space equipment is studied from several aspects， such as launch vehicles， satellite communications， satellite remote sensing， satellite navigation， manned spacecraft， and space situational awareness according to the dimensions of going into space， utilizing space， and controlling space. Finally， the trends of AI applications in space equipment are summarized. This work can be a reference for the development of AI applications in space equipment in China.

As a new combat force， the army synthetic brigade has many types of equipment， high degree of integration， and complex support problems. It has higher and higher requirements for "accurate support" of equipment. The digital twin technology is introduced into the field of equipment support. Through the analysis of the research object， the connotation and extension of the research system are outlined， and the operation law of the system is mastered. By constructing the framework of digital twin model， the structure of the digital twin model is described from the five dimensions of physical dimension， twin dimension， data dimension， application dimension and connection dimension， the key technologies for the establishment of each dimension of the model are clarified， the application assumption of the model is explored， and finally the digital twin model of the typical equipment support system of the army synthetic brigade is constructed to solve the complex problems faced by the equipment support of the army synthetic brigade. It provides a method reference for the realization of the goal of "accurate support" of equipment.