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: "secure broadcasting over fading channels with statistical qos constraints"
  Abstract: In this paper, the fading broadcast channel with confidential messages is studied in the presence of statistical quality of service (QoS) constraints in the form of limitations on the buffer length. We employ the effective capacity formulation to measure the throughput of the confidential and common messages. We assume that the channel side information (CSI) is available at both the transmitter and the receivers. Assuming average power constraints at the transmitter side, we first define the effective secure throughput region, and prove that the throughput region is convex. Then, we obtain the optimal power control policies that achieve the boundary points of the effective secure throughput region.

Connected through hyperedge HE-1 (induced by source paper "practical ldpc coded modulation schemes for the fading broadcast channel with confidential messages"):
  with members:
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "a physical layer secured key distribution technique for ieee 802 11g wireless networks"
    - "coding with scrambling concatenation and harq for the awgn wire tap channel a security gap analysis"
    - "broadcast channels with confidential messages by randomness constrained stochastic encoder"
    - "secret sharing ldpc codes for the bpsk constrained gaussian wiretap channel"
    - "increasing physical layer security through scrambled codes and arq"
    - "capacity region of gaussian mimo broadcast channels with common and confidential messages"
    - "non systematic codes for physical layer security"

Connected through hyperedge HE-2 (induced by source paper "secure wireless communication and optimal power control under statistical queueing constraints"):
  with members:
    - "secure communication over fading channels with statistical qos constraints"
    - "on the delay limited secrecy capacity of fading channels"
    - "the impact of qos constraints on the energy efficiency of fixed rate wireless transmissions"
    - "discrete memoryless interference and broadcast channels with confidential messages secrecy rate regions"
    - "secrecy capacity of a class of broadcast channels with an eavesdropper"
    - "analysis of energy efficiency in fading channels under qos constraints"

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)