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: "relay selection and resource allocation for two way df af cognitive radio networks"
  Abstract: In this letter, the problem of optimal resource power allocation and relay selection for two way relaying cognitive radio networks using half duplex Decode and Forward (DF) and Amplify and Forward (AF) systems are investigated. The primary and secondary networks are assumed to access the spectrum at the same time, so that the interference introduced to the primary network caused by the secondary network should be below a certain interference threshold. In addition, a selection strategy between the AF and DF schemes is applied depending on the achieved secondary sum rate without affecting the quality of service of the primary network. A suboptimal approach based on a genetic algorithm is also presented to solve our problem. Selected simulation results show that the proposed suboptimal algorithm offers a performance close to the performance of the optimal solution with a considerable complexity saving.

Connected through hyperedge HE-1 (induced by source paper "optimal relaying beamforming in multiple access broadcast channel mabc bidirectional cognitive radio networks in presence of interferers"):
  with members:
    - "a reputation based stackelberg game model to enhance secrecy rate in spectrum leasing to selfish iot devices"
    - "resource allocation and outage analysis for an adaptive cognitive two way relay network"
    - "spectrum sharing in cooperative cognitive radio networks a matching game framework"
    - "energy efficient power allocation in cognitive radio systems with imperfect spectrum sensing"
    - "cooperative algorithms for mimo amplify and forward relay networks"
    - "cognitive radio an information theoretic perspective"

Connected through hyperedge HE-2 (induced by source paper "resource allocation and outage analysis for an adaptive cognitive two way relay network"):
  with members:
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "achievable rate regions for bi directional relaying"

Connected through hyperedge HE-3 (induced by source paper "multipair two way half duplex relaying with massive arrays and imperfect csi"):
  with members:
    - "performance analysis and scaling law of mrc mrt relaying with csi error in massive mimo systems"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "massive mimo with optimal power and training duration allocation"
    - "massive mimo for next generation wireless systems"
    - "multi pair amplify and forward relaying with very large antenna arrays"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"

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)