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: "joint power splitting and secure beamforming design in the wireless powered untrusted relay networks"
  Abstract: In this work, we maximize the secrecy rate of the wireless-powered untrusted relay network by jointly designing power splitting (PS) ratio and relay beamforming with the proposed global optimal algorithm (GOA) and local optimal algorithm (LOA). Different from the literature, artificial noise (AN) sent by the destination not only degrades the channel condition of the eavesdropper to improve the secrecy rate, but also becomes a new source of energy powering the untrusted relay based on PS. Hence, it is of high economic benefits and efficiency to take advantage of AN compared with the literature. Simulation results show that LOA can achieve satisfactory secrecy rate performance compared with that of GOA, but with less computation time.

Connected through hyperedge HE-1 (induced by source paper "on secure communication using rf energy harvesting two way untrusted relay"):
  with members:
    - "interference aided energy harvesting cognitive relaying with multiple primary transceivers"
    - "secure communication via a wireless energy harvesting untrusted relay"
    - "secure communication via an untrusted non regenerative relay in fading channels"
    - "relaying protocols for wireless energy harvesting and information processing"
    - "wireless information and power transfer in two way amplify and forward relaying channels"
    - "wireless information and power transfer architecture design and rate energy tradeoff"
    - "robust beamforming for wireless information and power transmission"
    - "construction of wiretap codes from ordinary channel codes"

Connected through hyperedge HE-2 (induced by source paper "destination aided wireless power transfer in energy limited cognitive relay systems"):
  with members:
    - "transceiver design to maximize the weighted sum secrecy rate in full duplex swipt systems"
    - "joint wireless information and power transfer for an autonomous multiple antenna relay system"
    - "multi objective optimization for robust power efficient and secure full duplex wireless communication systems"
    - "joint beamforming optimization and power control for full duplex mimo two way relay channel"
    - "information and energy cooperation in cognitive radio networks"
    - "secrecy wireless information and power transfer with miso beamforming"
    - "throughput maximization in wireless powered communication networks"
    - "cooperative cognitive networks optimal distributed and low complexity algorithms"

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)