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: "on the secrecy outage capacity of physical layer security in large scale mimo relaying systems with imperfect csi"
  Abstract: In this paper, we study the problem of physical layer security in a large-scale multiple-input multiple-output (LS-MIMO) relaying system. The advantage of LS-MIMO relaying systems is exploited to enhance both wireless security and spectral efficiency. In particular, the challenging issue incurred by short interception distance is well addressed. Under very practical assumptions, i.e., no eavesdropper's channel state information (CSI) and imperfect legitimate channel CSI, this paper gives a thorough investigation of the impact of imperfect CSI in two classic relaying systems, i.e., amplify-and-forward (AF) and decode-and-forward (DF) systems, and obtain explicit expressions of secrecy outage capacities for both cases. Finally, our theoretical claims are validated by the numerical results.

Connected through hyperedge HE-1 (induced by source paper "enabling security and high energy efficiency in the internet of things with massive mimo hybrid precoding"):
  with members:
    - "joint optimization of computation and communication power in multi user massive mimo systems"
    - "secure massive mimo systems with limited rf chains"
    - "energy efficiency optimization of 5g radio frequency chain systems"
    - "physical layer security in heterogeneous cellular networks"
    - "large scale mimo relaying techniques for physical layer security af or df"
    - "jamming aided secure communication in massive mimo rician channels"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "low complexity hybrid precoding in massive multiuser mimo systems"

Connected through hyperedge HE-2 (induced by source paper "wireless security with beamforming technique"):
  with members:
    - "physical layer cryptography through massive mimo"
    - "location based beamforming for enhancing secrecy in rician wiretap channels"
    - "jamming aided secure communication in massive mimo rician channels"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "rethinking the secrecy outage formulation a secure transmission design perspective"
    - "cooperative jamming for secure communications in mimo relay networks"
    - "robust beamforming for security in mimo wiretap channels with imperfect csi"

Connected through hyperedge HE-3 (induced by source paper "large scale mimo relaying techniques for physical layer security af or df"):
  with members:
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "multi antenna relay aided wireless physical layer security"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "exploiting large scale mimo techniques for physical layer security with imperfect channel state information"
    - "performance analysis for physical layer security in multi antenna downlink networks with limited csi feedback"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "large system analysis of linear precoding in miso broadcast channels with confidential messages"

Connected through hyperedge HE-4 (induced by source paper "multi antenna relay aided wireless physical layer security"):
  with members:
    - "ergodic capacity comparison of different relay precoding schemes in dual hop af systems with co channel interference"
    - "cooperation with an untrusted relay a secrecy perspective"

Connected through hyperedge HE-5 (induced by source paper "optimal power allocation for secure communications in large scale mimo relaying systems"):
  with members:
    - "performance analysis for physical layer security in multi antenna downlink networks with limited csi feedback"
    - "cooperative jamming for secure communications in mimo relay networks"

Connected through hyperedge HE-6 (induced by source paper "secure wireless information and power transfer in large scale mimo relaying systems with imperfect csi"):
  with members:
    - "secrecy wireless information and power transfer with miso beamforming"
    - "energy efficient optimization for wireless information and power transfer in large scale mimo systems employing energy beamforming"
    - "simultaneous information and power transfer for broadband wireless systems"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "relay selection for simultaneous information transmission and wireless energy transfer a tradeoff perspective"
    - "wireless information and power transfer in two way amplify and forward relaying channels"
    - "robust beamforming for wireless information and power transmission"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

Connected through hyperedge HE-7 (induced by source paper "energy efficient power allocation for secure communications in large scale mimo relaying systems"):
  with members:
    - "energy efficient joint source and channel sensing in cognitive radio sensor networks"
    - "secure beamforming for mimo two way communications with an untrusted relay"
    - "performance analysis for physical layer security in multi antenna downlink networks with limited csi feedback"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "large system analysis of linear precoding in miso broadcast channels with confidential messages"
    - "energy efficient optimization for physical layer security in multi antenna downlink networks with qos guarantee"
    - "cooperative jamming for secure communications in mimo relay networks"

Connected through hyperedge HE-8 (induced by source paper "a semiblind two way training method for discriminatory channel estimation in mimo systems"):
  with members:
    - "two way training for discriminatory channel estimation in wireless mimo systems"
    - "on the design of artificial noise aided secure multi antenna transmission in slow fading channels"
    - "relay selection for two way relaying with amplify and forward protocols"
    - "robust beamforming for security in mimo wiretap channels with imperfect csi"
    - "secure transmission with artificial noise over fading channels achievable rate and optimal power allocation"

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)