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: "optimal real time spectrum sharing between cooperative relay and ad hoc networks"
  Abstract: Optimization based spectrum sharing strategies have been widely studied. However, these strategies usually require a great amount of real-time computation and significant control delay, and thus are hard to be fulfilled in practical scenarios. This paper investigates optimal real-time spectrum sharing between a cooperative relay network (CRN) and a nearby ad hoc network. Specifically, we optimize the spectrum access and resource allocation strategies of the CRN so that the average traffic collision time between the two networks can be minimized while maintaining a required throughput for the CRN. The development is first for a frame-level setting, and then is extended to an ergodic setting. For the latter setting, we propose an appealing optimal real-time spectrum sharing strategy via Lagrangian dual optimization. The proposed method only involves a small amount of real-time computation and negligible control delay, and thus is suitable for practical implementations. Simulation results are presented to demonstrate the efficiency of the proposed strategies.

Connected through hyperedge HE-1 (induced by source paper "capacity region bounds and resource allocation for two way ofdm relay channels"):
  with members:
    - "outer bounds for the capacity region of a gaussian two way relay channel"
    - "optimal power allocation for two way decode and forward ofdm relay networks"
    - "a tutorial on the optimization of amplify and forward mimo relay systems"
    - "optimization framework and graph based approach for relay assisted bidirectional ofdma cellular networks"
    - "broadcast capacity region of two phase bidirectional relaying"
    - "on the capacity and diversity multiplexing tradeoff of the two way relay channel"
    - "mimo two way relay channel diversity multiplexing tradeoff analysis"

Connected through hyperedge HE-2 (induced by source paper "optimal power allocation for two way decode and forward ofdm relay networks"):
  with members:
    - "joint subcarrier pairing and power allocation for ofdm transmission with decode and forward relaying"
    - "resource allocation for wireless fading relay channels max min solution"

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)