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: "wireless powered cooperative jamming for secrecy multi af relaying networks"
  Abstract: This paper studies secrecy transmission with the aid of a group of wireless energy harvesting (WEH)-enabled amplify-and-forward (AF) relays performing cooperative jamming (CJ) and relaying. The source node in the network does simultaneous wireless information and power transfer (SWIPT) with each relay employing a power splitting (PS) receiver in the first phase; each relay further divides its harvested power for forwarding the received signal and generating artificial noise (AN) for jamming the eavesdroppers in the second transmission phase. In the centralized case with global channel state information (CSI), we provide closed-form expressions for the optimal and/or suboptimal AF-relay beamforming vectors to maximize the achievable secrecy rate subject to individual power constraints of the relays, using the technique of semidefinite relaxation (SDR), which is proved to be tight. A fully distributed algorithm utilizing only local CSI at each relay is also proposed as a performance benchmark. Simulation results validate the effectiveness of the proposed multi-AF relaying with CJ over other suboptimal designs.

Connected through hyperedge HE-1 (induced by source paper "a survey of physical layer security techniques for 5g wireless networks and challenges ahead"):
  with members:
    - "secure massive mimo systems with limited rf chains"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "probabilistically robust swipt for secrecy misome systems"
    - "exploiting full duplex receivers for achieving secret communications in multiuser miso networks"
    - "full duplex bidirectional secure communications under perfect and distributionally ambiguous eavesdropper s csi"
    - "safeguarding decentralized wireless networks using full duplex jamming receivers"
    - "physical layer security aware routing and performance tradeoffs in ad hoc networks"
    - "hybrid procoder and combiner design for secure transmission in mmwave mimo systems"

Connected through hyperedge HE-2 (induced by source paper "wireless powered cooperative jamming for secure ofdm system"):
  with members:
    - "waveform optimization for radio frequency wireless power transfer"
    - "waveform design for wireless power transfer"
    - "secrecy wireless information and power transfer in fading wiretap channel"
    - "a general design framework for mimo wireless energy transfer with limited feedback"
    - "wireless power transfer in massive mimo aided hetnets with user association"
    - "accumulate and jam towards secure communication via a wireless powered full duplex jammer"
    - "communications and signals design for wireless power transmission"
    - "to harvest and jam a paradigm of self sustaining friendly jammers for secure af relaying"

Connected through hyperedge HE-3 (induced by source paper "exploiting interference for secrecy wireless information and power transfer"):
  with members:
    - "secrecy wireless information and power transfer in fading wiretap channel"
    - "secrecy wireless information and power transfer challenges and opportunities"
    - "accumulate and jam towards secure communication via a wireless powered full duplex jammer"
    - "artificial noise aided secrecy information and power transfer in ofdma systems"
    - "to harvest and jam a paradigm of self sustaining friendly jammers for secure af relaying"
    - "wireless powered communication opportunities and challenges"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "simultaneous wireless information and power transfer in modern communication systems"

Connected through hyperedge HE-4 (induced by source paper "optimizing df cognitive radio networks with full duplex enabled energy access points"):
  with members:
    - "robust resource allocation for mimo wireless powered communication networks based on a non linear eh model"
    - "wireless powered communication networks an overview"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "cognitive wireless powered network spectrum sharing models and throughput maximization"
    - "comp meets smart grid a new communication and energy cooperation paradigm"
    - "energy efficient resource allocation for wireless powered communication networks"
    - "joint resource optimization for multicell networks with wireless energy harvesting relays"
    - "information and energy cooperation in cognitive radio 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)