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: "optimized training for net energy maximization in multi antenna wireless energy transfer over frequency selective channel"
  Abstract: This paper studies the training design problem for multiple-input single-output (MISO) wireless energy transfer (WET) systems in frequency-selective channels, where the frequency-diversity and energy-beamforming gains can be both reaped to maximize the transferred energy by efficiently learning the channel state information (CSI) at the energy transmitter (ET). By exploiting channel reciprocity, a new two-phase channel training scheme is proposed to achieve the diversity and beamforming gains, respectively. In the first phase, pilot signals are sent from the energy receiver (ER) over a selected subset of the available frequency sub-bands, through which the ET determines a certain number of "strongest" sub-bands with largest antenna sum-power gains and sends their indices to the ER. In the second phase, the selected sub-bands are further trained by the ER, so that the ET obtains a refined estimate of the corresponding MISO channels to implement energy beamforming for WET. A training design problem is formulated and optimally solved, which takes into account the channel training overhead by maximizing the net harvested energy at the ER, defined as the average harvested energy offset by that consumed in the two-phase training. Moreover, asymptotic analysis is obtained for systems with a large number of antennas or a large number of sub-bands to gain useful insights on the optimal training design. Finally, numerical results are provided to corroborate our analysis and show the effectiveness of the proposed scheme that optimally balances the diversity and beamforming gains achieved in MISO WET systems with limited-energy training.

Connected through hyperedge HE-1 (induced by source paper "cognitive wireless power transfer in the presence of reactive primary communication user"):
  with members:
    - "fundamentals of wireless information and power transfer from rf energy harvester models to signal and system designs"
    - "large scale multiantenna multisine wireless power transfer"
    - "distributed wireless power transfer with energy feedback"
    - "joint offloading and computing optimization in wireless powered mobile edge computing systems"
    - "waveform optimization for radio frequency wireless power transfer"
    - "waveform design for wireless power transfer"
    - "surveillance and intervention of infrastructure free mobile communications a new wireless security paradigm"
    - "a general design framework for mimo wireless energy transfer with limited feedback"

Connected through hyperedge HE-2 (induced by source paper "design of ambient backscatter training for retrodirective wireless power transfer"):
  with members:
    - "retrodirective large antenna energy beamforming in backscatter multi user networks"
    - "retrodirective multi user wireless power transfer with massive mimo"
    - "next generation backscatter communication systems techniques and applications"
    - "ambient backscatter communications a contemporary survey"
    - "modulation in the air backscatter communication over ambient ofdm carrier"
    - "inter technology backscatter towards internet connectivity for implanted devices"
    - "communications and signals design for wireless power transmission"
    - "wireless powered communication opportunities and challenges"

Connected through hyperedge HE-3 (induced by source paper "opportunistic wireless energy beamforming using rssi feedback"):
  with members:
    - "wireless energy transfer to a pair of energy receivers using signal strength feedback"
    - "wireless energy beamforming using received signal strength indicator feedback"
    - "over the air implementation of uplink noma"
    - "on the efficiency of far field wireless power transfer"
    - "energy beamforming with one bit feedback"
    - "throughput maximization in wireless powered communication networks"
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "a novel mode switching scheme utilizing random beamforming for opportunistic energy harvesting"

Connected through hyperedge HE-4 (induced by source paper "statistical analysis of multiple antenna strategies for wireless energy transfer"):
  with members:
    - "rate control for wireless powered communication network with reliability and delay constraints"
    - "fundamentals of wireless information and power transfer from rf energy harvester models to signal and system designs"
    - "ultra reliable cooperative short packet communications with wireless energy transfer"
    - "on the beneficial roles of fading and transmit diversity in wireless power transfer with nonlinear energy harvesting"
    - "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"
    - "on the performance of multi antenna wireless powered communications with energy beamforming"
    - "wireless powered communication networks an overview"
    - "communications and signals design for wireless power transmission"

Connected through hyperedge HE-5 (induced by source paper "cluster based wireless energy transfer for low complex energy receivers"):
  with members:
    - "wireless energy transfer to a pair of energy receivers using signal strength feedback"
    - "wireless energy beamforming using received signal strength indicator feedback"
    - "waveform design for wireless power transfer with limited feedback"
    - "over the air implementation of uplink noma"
    - "on the efficiency of far field wireless power transfer"
    - "energy beamforming with one bit feedback"
    - "throughput maximization in wireless powered communication networks"
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"

Connected through hyperedge HE-6 (induced by source paper "wireless energy beamforming using received signal strength indicator feedback"):
  with members:
    - "a general design framework for mimo wireless energy transfer with limited feedback"
    - "wireless powered communication opportunities and challenges"
    - "throughput optimization for massive mimo systems powered by wireless energy transfer"
    - "enhancing wireless information and power transfer by exploiting multi antenna techniques"
    - "multiuser mimo wireless energy transfer with coexisting opportunistic communication"
    - "energy beamforming with one bit feedback"
    - "optimized training design for wireless energy transfer"
    - "dynamic resource allocation for multiple antenna wireless power transfer"

Connected through hyperedge HE-7 (induced by source paper "wireless energy transfer to a pair of energy receivers using signal strength feedback"):
  with members:
    - "wireless energy beamforming using received signal strength indicator feedback"
    - "enhancing wireless information and power transfer by exploiting multi antenna techniques"
    - "multiuser mimo wireless energy transfer with coexisting opportunistic communication"
    - "energy beamforming with one bit feedback"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "energy efficient optimization for wireless information and power transfer in large scale mimo systems employing energy beamforming"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

Connected through hyperedge HE-8 (induced by source paper "distributed wireless power transfer with energy feedback"):
  with members:
    - "a general design framework for mimo wireless energy transfer with limited feedback"
    - "wireless powered communication networks an overview"
    - "some new research trends in wirelessly powered communications"
    - "wireless powered communication opportunities and challenges"
    - "distributed energy beamforming with one bit feedback"
    - "collaborative wireless energy and information transfer in interference channel"
    - "simultaneous wireless information and power transfer in modern communication systems"
    - "energy beamforming with one bit feedback"

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)