human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "safeguarding wireless network with uavs a physical layer security perspective"
  Abstract: Integrating unmanned aerial vehicles (UAVs) into future wireless systems such as the fifth-generation (5G) cellular network is anticipated to bring significant benefits for both UAV and telecommunication industries. Generally speaking, UAVs can be used as new aerial platforms in the cellular network to provide communication services for terrestrial users, or become new aerial users of the cellular network served by the terrestrial base stations. Due to their high altitude, UAVs usually have dominant line-of-sight (LoS) channels with the ground nodes, which, however, pose new security challenges to future wireless networks with widely deployed UAVs. On one hand, UAV-ground communications are more prone than terrestrial communications to eavesdropping and jamming attacks by malicious nodes on the ground. On the other hand, compared to malicious ground nodes, malicious UAVs can launch more effective eavesdropping and jamming attacks to terrestrial communications. Motivated by the above, in this article, we aim to identify such new issues from a physical-layer security viewpoint and propose novel solutions to tackle them efficiently. Numerical results are provided to validate their effectiveness and promising directions for future research are also discussed.

Connected through hyperedge HE-1 (induced by source paper "resource allocation for secure multi uav communication systems with multi eavesdropper"):
  with members:
    - "robust trajectory and resource allocation design for secure uav aided communications"
    - "energy efficient resource allocation for secure uav communication systems"
    - "physical layer security in uav systems challenges and opportunities"
    - "cognitive uav communication via joint maneuver and power control"
    - "secrecy energy efficiency maximization for uav enabled mobile relaying"
    - "joint altitude beamwidth location and bandwidth optimization for uav enabled communications"
    - "optimal 3d trajectory design and resource allocation for solar powered uav communication systems"
    - "securing uav communications via joint trajectory and power control"

Connected through hyperedge HE-2 (induced by source paper "secrecy and covert communications against uav surveillance via multi hop networks"):
  with members:
    - "coverage probability analysis of uav cellular networks in urban environments"
    - "secure routing with power optimization for ad hoc networks"
    - "securing uav communications via joint trajectory and power control"
    - "multi hop routing in covert wireless networks"
    - "robust trajectory and transmit power design for secure uav communications"
    - "securing uav communications via trajectory optimization"
    - "covert communication in fading channels under channel uncertainty"
    - "secure transmission in linear multihop relaying networks"

Connected through hyperedge HE-3 (induced by source paper "on the performance of low altitude uav enabled secure af relaying with cooperative jamming and swipt"):
  with members:
    - "energy efficient resource allocation for secure uav communication systems"
    - "uav communications for 5g and beyond recent advances and future trends"
    - "secrecy transmission in large scale uav enabled wireless networks"
    - "secure two way transmission via wireless powered untrusted relay and external jammer"
    - "ultra reliable uav communication using altitude and cooperation diversity"
    - "secure two way communication via a wireless powered untrusted relay and friendly jammer"
    - "an overview of sustainable green 5g networks"
    - "a survey on wireless security technical challenges recent advances and future trends"

Connected through hyperedge HE-4 (induced by source paper "energy efficiency maximization for full duplex uav secrecy communication"):
  with members:
    - "secrecy energy efficiency maximization for uav enabled mobile relaying"
    - "securing uav communications via joint trajectory and power control"
    - "energy minimization for wireless communication with rotary wing uav"
    - "secure uav communication with cooperative jamming and trajectory control"
    - "multipair full duplex relaying with massive arrays and linear processing"

Connected through hyperedge HE-5 (induced by source paper "joint optimization of a uav s trajectory and transmit power for covert communications"):
  with members:
    - "gaussian signalling for covert communications"
    - "capacity characterization of uav enabled two user broadcast channel"
    - "covert communication achieved by a greedy relay in wireless networks"
    - "joint trajectory and communication design for multi uav enabled wireless networks"
    - "securing uav communications via trajectory optimization"
    - "covert wireless communication with a poisson field of interferers"
    - "energy efficient data collection in uav enabled wireless sensor network"
    - "on covert communication with noise uncertainty"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.IT(Information Theory)