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: "optimum wirelessly powered relaying"
  Abstract: This letter maximizes the achievable throughput of a relay-assisted wirelessly powered communications system, where an energy constrained source, assisted by an energy constrained relay and both powered by a dedicated power beacon (PB), communicates with a destination. Considering the time splitting approach, the source and relay first harvest energy from the PB, which is equipped with multiple antennas, and then transmits the information to destination. Simple closed-form expressions are derived for the optimal PB energy beamforming vector and time split for energy harvesting and information transmission. Numerical results and simulations demonstrate the superior performance compared with some intuitive benchmark beamforming scheme. Also, it is found that placing the relay at the middle of the source-destination path is no longer optimal.

Connected through hyperedge HE-1 (induced by source paper "transmission delay minimization in wireless powered communication systems"):
  with members:
    - "power allocation and effective capacity of af successive relays"
    - "optimization and analysis of wireless powered multi antenna cooperative systems"
    - "cross layer optimization for ultra reliable and low latency radio access networks"
    - "wireless powered dual hop multi antenna relaying systems impact of csi and antenna correlation"
    - "effective capacity of receive antenna selection mimo ostbc systems in co channel interference"
    - "wireless charging technologies fundamentals standards and network applications"
    - "wireless powered communication networks an overview"
    - "some new research trends in wirelessly powered communications"

Connected through hyperedge HE-2 (induced by source paper "finite horizon throughput maximization and sensing optimization in wireless powered devices over fading channels"):
  with members:
    - "a survey on mobile edge computing the communication perspective"
    - "a tutorial on thompson sampling"
    - "computation rate maximization for wireless powered mobile edge computing"
    - "non orthogonal multiple access schemes in wireless powered communication networks"
    - "user cooperation for enhanced throughput fairness in wireless powered communication networks"
    - "battery powered devices in wpcns"
    - "on optimal policies in full duplex wireless powered communication networks"
    - "an adaptive transmission protocol for wireless powered cooperative communications"

Connected through hyperedge HE-3 (induced by source paper "optimization and analysis of wireless powered multi antenna cooperative systems"):
  with members:
    - "on the performance of multi antenna wireless powered communications with energy beamforming"
    - "relaying strategies for wireless powered mimo relay networks"
    - "wireless powered communication opportunities and challenges"
    - "on the efficiency of far field wireless power transfer"
    - "wireless powered communications performance analysis and optimization"
    - "energy efficient resource allocation for wireless powered communication networks"
    - "spatial throughput maximization of wireless powered communication networks"
    - "harvest then cooperate wireless powered cooperative communications"

Connected through hyperedge HE-4 (induced by source paper "resource allocation strategies for secure wpcn multiantenna multicasting systems"):
  with members:
    - "physical layer security in mimo backscatter wireless systems"
    - "wireless powered communication networks an overview"
    - "harvest then cooperate wireless powered cooperative communications"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "massive mimo multicasting in noncooperative cellular networks"
    - "wireless powered cooperative communications via a hybrid relay"
    - "user cooperation in wireless powered communication networks"
    - "secrecy wireless information and power transfer with miso beamforming"

Connected through hyperedge HE-5 (induced by source paper "optimal power allocation by imperfect hardware analysis in untrusted relaying networks"):
  with members:
    - "joint relay selection and power allocation in large scale mimo systems with untrusted relays and passive eavesdroppers"
    - "optimal power allocation and secrecy sum rate in two way untrusted relaying"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "physical layer security for massive mimo systems impaired by phase noise"
    - "joint relay and jammer selection improves the physical layer security in the face of csi feedback delays"
    - "physical layer security for massive mimo an overview on passive eavesdropping and active attacks"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-6 (induced by source paper "resource allocation and fairness in wireless powered cooperative cognitive radio networks"):
  with members:
    - "wireless powered communication opportunities and challenges"
    - "placement optimization of energy and information access points in wireless powered communication networks"
    - "cognitive wireless powered network spectrum sharing models and throughput maximization"
    - "on information and energy cooperation in energy harvesting cognitive radio"
    - "harvest then cooperate wireless powered cooperative communications"
    - "user cooperation in wireless powered communication networks"
    - "information and energy cooperation in cognitive radio networks"
    - "optimal resource allocation in full duplex wireless powered communication network"

Connected through hyperedge HE-7 (induced by source paper "multi antenna wireless powered communication with co channel energy and information transfer"):
  with members:
    - "wireless power meets energy harvesting a joint energy allocation approach in ofdm based system"
    - "multiuser mimo wireless energy transfer with coexisting opportunistic communication"
    - "spatial throughput maximization of wireless powered communication networks"
    - "joint beamforming design and time allocation for wireless powered communication networks"
    - "energy beamforming with one bit feedback"
    - "full duplex wireless powered relay with self energy recycling"
    - "secure communication with a wireless powered friendly jammer"
    - "throughput maximization in wireless powered communication networks"

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)