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( Zongyi Liu ),( Guomei Zhang ),( Wei Meng ),( Xiaohui Ma ),( Guobing Li ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.3
Cognitive radio (CR) is regarded as an effective approach to avoid the inefficient use of spectrum. However, CRNs have more special security problems compared with the traditional wireless communication systems due to its open and dynamic characteristics. Primary user emulation attack (PUEA) is a common method which can hinder secondary users (SUs) from accessing the spectrum by transmitting signals who has the similar characteristics of the primary users’ (PUs) signals, and then the SUs’ quality of service (QoS) cannot be guaranteed. To handle this issue, we first design a multiple-phase energy detection scheme based on the cooperation of multiple SUs to detect the PUEA more precisely. Second, a joint SUs scheduling and power allocation scheme is proposed to maximize the weighted effective capacity of multiple SUs with a constraint of the average interference to the PU. The simulation results show that the proposed method can effectively improve the effective capacity of the secondary users compared with the traditional overlay scheme which cannot be aware of the existence of PUEA. Also the good delay QoS guarantee for the secondary users is provided.
Hao Zhang,Jun Zhou,Guanghui Liu,Zongyi Guo 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.5
The thermal interface of a modular microsatellite can be equated to a multi-layer structure which is used to transfer heat between modules to maintain the temperature in a healthy range. To describe the heat transfer process at the thermal interface, an improved one-dimensional RC heat transfer model based on a thermal–electric analogy is proposed, considering both three complex heat transfer modes (heat conduction, radiation, and convection) and thermal contact resistance to describe the temperature variation at the thermal interface. Then, the temperature response of the novel thermal interface with five layers of materials is solved using step temperature boundary conditions, and the obtained temperature response is compared with the models considering only heat conduction. The comparison results show that the temperature prediction accuracy of the proposed model increased by 4.1%. Finally, experiments are designed and compared with the simulation results, which verify the validity of the proposed model.