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: "the random frequency diverse array a new antenna structure for uncoupled direction range indication in active sensing"
  Abstract: In this paper, we propose a new type of array antenna, termed the random frequency diverse array (RFDA), for an uncoupled indication of target direction and range with low system complexity. In RFDA, each array element has a narrow bandwidth and a randomly assigned carrier frequency. The beampattern of the array is shown to be stochastic but thumbtack-like, and its stochastic characteristics, such as the mean, variance, and asymptotic distribution are derived analytically. Based on these two features, we propose two kinds of algorithms for signal processing. One is matched filtering, due to the beampattern's good characteristics. The other is compressive sensing, because the new approach can be regarded as a sparse and random sampling of target information in the spatial-frequency domain. Fundamental limits, such as the Cramer–Rao bound and the observing matrix's mutual coherence, are provided as performance guarantees of the new array structure. The features and performances of RFDA are verified with numerical results.

Connected through hyperedge HE-1 (induced by source paper "secure precise wireless transmission with random subcarrier selection based directional modulation transmit antenna array"):
  with members:
    - "covert communication in wireless relay networks"
    - "symbol level and multicast precoding for multiuser multiantenna downlink a survey classification and challenges"
    - "artificial noise aided secure transmission in wiretap channels with transmitter side correlation"
    - "location based beamforming for enhancing secrecy in rician wiretap channels"
    - "directional modulation via symbol level precoding a way to enhance security"
    - "improving physical layer security in wireless communications using diversity techniques"
    - "relay selection improves the security reliability trade off in cognitive radio systems"
    - "optimization of code rates in sisome wiretap channels"

Connected through hyperedge HE-2 (induced by source paper "artificial noise aided secure transmission with directional modulation based on random frequency diverse arrays"):
  with members:
    - "on secrecy metrics for physical layer security over quasi static fading channels"
    - "location based beamforming for enhancing secrecy in rician wiretap channels"
    - "secrecy wireless information and power transfer challenges and opportunities"
    - "improving physical layer security in wireless communications using diversity techniques"
    - "optimization of code rates in sisome wiretap channels"
    - "wireless physical layer security with imperfect channel state information a survey"

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)