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: "jointly optimal channel and power assignment for dual hop multi channel multi user relaying"
  Abstract: We consider the problem of jointly optimizing channel pairing, channel-user assignment, and power allocation, to maximize the weighted sum-rate, in a single-relay cooperative system with multiple channels and multiple users. Common relaying strategies are considered, and transmission power constraints are imposed on both individual transmitters and the aggregate over all transmitters. The joint optimization problem naturally leads to a mixed-integer program. Despite the general expectation that such problems are intractable, we construct an efficient algorithm to find an optimal solution, which incurs computational complexity that is polynomial in the number of channels and the number of users. We further demonstrate through numerical experiments that the jointly optimal solution can significantly improve system performance over its suboptimal alternatives.

Connected through hyperedge HE-1 (induced by source paper "energy efficient resource allocation for time varying ofdma relay systems with hybrid energy supplies"):
  with members:
    - "cross layer scheduling for ofdma based cognitive radio systems with delay and security constraints"
    - "power allocation for conventional and buffer aided link adaptive relaying systems with energy harvesting nodes"
    - "energy efficient resource allocation in ofdma systems with hybrid energy harvesting base station"
    - "maximizing energy efficiency in multi relay ofdma cellular networks"
    - "decentralized delay optimal control for interference networks with limited renewable energy storage"
    - "a cross layer perspective on energy harvesting aided green communications over fading channels"
    - "adaptive power management for wireless base stations in a smart grid environment"
    - "wsr maximized resource allocation in multiple df relays aided ofdma downlink transmission"

Connected through hyperedge HE-2 (induced by source paper "information and energy cooperation in ofdm relaying protocols and optimization"):
  with members:
    - "secrecy wireless information and power transfer in ofdma systems"
    - "wireless information and energy transfer for two hop non regenerative mimo ofdm relay networks"
    - "secure and green swipt in distributed antenna networks with limited backhaul capacity"
    - "power allocation strategies in energy harvesting wireless cooperative networks"
    - "wireless information and power transfer with full duplex relaying"
    - "energy cooperation in energy harvesting communications"
    - "simultaneous information and power transfer for broadband wireless systems"
    - "wireless information and power transfer in multiuser ofdm systems"

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)