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: "utility of beamforming strategies for secrecy in multiuser mimo wiretap channels"
  Abstract: This paper examines linear beamforming methods for secure communications in a multiuser wiretap channel with a single transmitter, multiple legitimate receivers, and a single eavesdropper, where all nodes are equipped with multiple antennas. No information regarding the eavesdropper is presumed at the transmitter, and we examine both the broadcast MIMO downlink with independent information, and the multicast MIMO downlink with common information for all legitimate receivers. In both cases the information signal is transmitted with just enough power to guarantee a certain SINR at the desired receivers, while the remainder of the power is used to broadcast artificial noise. The artificial interference selectively degrades the passive eavesdropper's signal while remaining orthogonal to the desired receivers. We analyze the confidentiality provided by zero-forcing and optimal minimum-power beamforming designs for the broadcast channel, and optimal minimum-MSE beamformers for the multicast channel. Numerical simulations for the relative SINR and BER performance of the eavesdropper demonstrate the effectiveness of the proposed physical-layer security schemes.

Connected through hyperedge HE-1 (induced by source paper "enhancing phy security of cooperative cognitive radio multicast communications"):
  with members:
    - "robust beamforming for secrecy rate in cooperative cognitive radio multicast communications"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secrecy wireless information and power transfer with miso beamforming"
    - "improving physical layer secrecy using full duplex jamming receivers"
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "on the design of artificial noise aided secure multi antenna transmission in slow fading channels"
    - "capacity theorems for the cognitive radio channel with confidential messages"
    - "on secrecy rate of the generalized artificial noise assisted secure beamforming for wiretap channels"

Connected through hyperedge HE-2 (induced by source paper "robust beamforming for secrecy rate in cooperative cognitive radio multicast communications"):
  with members:
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "secure transmission with artificial noise over fading channels achievable rate and optimal power allocation"

Connected through hyperedge HE-3 (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"
    - "on the secrecy outage capacity of physical layer security in large scale mimo relaying systems with imperfect csi"
    - "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"

Connected through hyperedge HE-4 (induced by source paper "apply artificial noise to secure fading relay networks a ser based approach"):
  with members:
    - "secure communication via an untrusted non regenerative relay in fading channels"
    - "imbalanced beamforming by a multi antenna source for secure utilization of an untrusted relay"
    - "jamming games in the mimo wiretap channel with an active eavesdropper"
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "secrecy sum rates for multi user mimo regularized channel inversion precoding"
    - "a tutorial on the optimization of amplify and forward mimo relay systems"
    - "physical layer network coding tutorial survey and beyond"
    - "solutions for the mimo gaussian wiretap channel with a cooperative jammer"

Connected through hyperedge HE-5 (induced by source paper "wiretapped signal leakage minimization for secure multiuser mimo systems via interference alignment"):
  with members:
    - "secrecy sum rates for multi user mimo regularized channel inversion precoding"
    - "interference alignment for secrecy"

Connected through hyperedge HE-6 (induced by source paper "filter design with secrecy constraints the mimo gaussian wiretap channel"):
  with members:
    - "achieving the secrecy capacity of wiretap channels using polar codes"
    - "robust beamforming for security in mimo wiretap channels with imperfect csi"
    - "strong secrecy for erasure wiretap channels"
    - "towards the secrecy capacity of the gaussian mimo wire tap channel the 2 2 1 channel"
    - "the secrecy capacity of the mimo wiretap channel"
    - "applications of ldpc codes to the wiretap channel"

Connected through hyperedge HE-7 (induced by source paper "two way training for discriminatory channel estimation in wireless mimo systems"):
  with members:
    - "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"
    - "the secrecy capacity of the mimo wiretap channel"

Connected through hyperedge HE-8 (induced by source paper "optimal and robust transmit designs for miso channel secrecy by semidefinite programming"):
  with members:
    - "robust beamforming for security in mimo wiretap channels with imperfect csi"
    - "on the relationship between the multi antenna secrecy communications and cognitive radio communications"
    - "transmitter optimization for achieving secrecy capacity in gaussian mimo wiretap channels"
    - "the secrecy capacity of the mimo wiretap channel"

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)