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: "secrecy outage and diversity analysis of cognitive radio systems"
  Abstract: In this paper, we investigate the physical-layer security of a multi-user multi-eavesdropper cognitive radio system, which is composed of multiple cognitive users (CUs) transmitting to a common cognitive base station (CBS), {while multiple eavesdroppers may collaborate with each other or perform independently in intercepting the CUs-CBS transmissions, which are called the coordinated and uncoordinated eavesdroppers, respectively}. Considering multiple CUs available, we propose the round-robin scheduling as well as the optimal and suboptimal user scheduling schemes for improving the security of CUs-CBS transmissions against eavesdropping attacks. Specifically, the optimal user scheduling is designed by assuming that the channel state information (CSI) of all links from CUs to CBS, to primary user (PU) and to eavesdroppers are available. By contrast, the suboptimal user scheduling only requires the CSI of CUs-CBS links without the PU's and eavesdroppers' CSI. We derive closed-form expressions of the secrecy outage probability of these three scheduling schemes in the presence of {the coordinated and uncoordinated eavesdroppers}. We also carry out the secrecy diversity analysis and show that the round-robin scheduling achieves the diversity order of only one, whereas the optimal and suboptimal scheduling schemes obtain the full secrecy diversity, {no matter whether the eavesdroppers collaborate or not. In addition, numerical secrecy outage results demonstrate that for both the coordinated and uncoordinated eavesdroppers, the optimal user scheduling achieves the best security performance and the round-robin scheduling performs the worst.} Finally, upon increasing the number of CUs, the secrecy outage probabilities of the optimal and suboptimal user scheduling schemes both improve significantly.

Connected through hyperedge HE-1 (induced by source paper "secrecy outage and diversity analysis of multiple cooperative source destination pairs"):
  with members:
    - "modulation and multiple access for 5g networks"
    - "physical layer security in heterogeneous networks with jammer selection and full duplex users"
    - "physical layer security for spectrum sharing systems"
    - "on secrecy performance of antenna selection aided mimo systems against eavesdropping"
    - "artificial noise aided secure transmission in large scale spectrum sharing networks"
    - "location based beamforming for enhancing secrecy in rician wiretap channels"
    - "physical layer security in heterogeneous cellular networks"
    - "secrecy transmit beamforming for heterogeneous networks"

Connected through hyperedge HE-2 (induced by source paper "security reliability tradeoff for distributed antenna systems in heterogeneous cellular networks"):
  with members:
    - "game based approach for qos provisioning and interference management in heterogeneous networks"
    - "intelligent interference exploitation for heterogeneous cellular networks against eavesdropping"
    - "energy efficiency analysis of heterogeneous cellular networks with extra cell range expansion"
    - "secrecy optimized resource allocation for device to device communication underlaying heterogeneous networks"
    - "safeguarding decentralized wireless networks using full duplex jamming receivers"
    - "optimal beamforming for gaussian mimo wiretap channels with two transmit antennas"
    - "relay selection for wireless communications against eavesdropping a security reliability trade off perspective"
    - "a survey on wireless security technical challenges recent advances and future trends"

Connected through hyperedge HE-3 (induced by source paper "on the secrecy performance of generalized user selection for interference limited multiuser wireless networks"):
  with members:
    - "on the asymptotic throughput of the k th best secondary user selection in cognitive radio systems"
    - "physical layer security in the presence of interference"

Connected through hyperedge HE-4 (induced by source paper "multi antenna wireless legitimate surveillance systems design and performance analysis"):
  with members:
    - "secure massive mimo systems with limited rf chains"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "on secrecy performance of antenna selection aided mimo systems against eavesdropping"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "throughput analysis and optimization of wireless powered multiple antenna full duplex relay systems"
    - "wireless information surveillance via proactive eavesdropping with spoofing relay"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "proactive eavesdropping via cognitive jamming in fading channels"

Connected through hyperedge HE-5 (induced by source paper "intelligent interference exploitation for heterogeneous cellular networks against eavesdropping"):
  with members:
    - "robust and secure resource allocation for full duplex miso multicarrier noma systems"
    - "physical layer security in wireless ad hoc networks under a hybrid full half duplex receiver deployment strategy"
    - "safeguarding decentralized wireless networks using full duplex jamming receivers"
    - "power constrained secrecy rate maximization for joint relay and jammer selection assisted wireless networks"
    - "relay selection for wireless communications against eavesdropping a security reliability trade off perspective"
    - "physical layer security for spectrum sharing systems"
    - "on secrecy performance of antenna selection aided mimo systems against eavesdropping"
    - "analytical modeling of interference aware power control for the uplink of heterogeneous cellular networks"

Connected through hyperedge HE-6 (induced by source paper "physical layer security in the presence of interference"):
  with members:
    - "spectrum sensing with multiple primary users over fading channels"
    - "what will 5g be"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "on the performance of non orthogonal multiple access in 5g systems with randomly deployed users"
    - "discrete memoryless interference and broadcast channels with confidential messages secrecy rate regions"

Connected through hyperedge HE-7 (induced by source paper "a survey on wireless security technical challenges recent advances and future trends"):
  with members:
    - "relay selection for wireless communications against eavesdropping a security reliability trade off perspective"
    - "improving physical layer security in wireless communications using diversity techniques"
    - "securing physical layer communications for cognitive radio networks"
    - "security versus reliability analysis of opportunistic relaying"
    - "what will 5g be"
    - "intercept probability analysis of cooperative wireless networks with best relay selection in the presence of eavesdropping attack"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "physical layer security with multiuser scheduling in cognitive radio networks"

Connected through hyperedge HE-8 (induced by source paper "robust an aided beamforming and power splitting design for secure miso cognitive radio with swipt"):
  with members:
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secure and green swipt in distributed antenna networks with limited backhaul capacity"
    - "simultaneous wireless information and power transfer in modern communication systems"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "on green energy powered cognitive radio networks"
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "outage constrained robust secure transmission for miso wiretap channels"
    - "robust secure transmission in miso channels based on worst case optimization"

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)