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: "relay placement for physical layer security a secure connection perspective"
  Abstract: This work studies the problem of secure connection in cooperative wireless communication with two relay strategies, decode-and-forward (DF) and randomize-and-forward (RF). The four-node scenario and cellular scenario are considered. For the typical four-node (source, destination, relay, and eavesdropper) scenario, we derive the optimal power allocation for the DF strategy and find that the RF strategy is always better than the DF to enhance secure connection. In cellular networks, we show that without relay, it is difficult to establish secure connections from the base station to the cell edge users. The effect of relay placement for the cell edge users is demonstrated by simulation. For both scenarios, we find that the benefit of relay transmission increases when path loss becomes severer.

Connected through hyperedge HE-1 (induced by source paper "link selection for secure cooperative networks with buffer aided relaying"):
  with members:
    - "physical layer security of a buffer aided full duplex relaying system"
    - "simultaneous bidirectional link selection in full duplex mimo systems"
    - "effect of spatial interference correlation on the performance of maximum ratio combining"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "buffer aided relaying with adaptive link selection"
    - "buffer aided relaying with adaptive link selection fixed and mixed rate transmission"
    - "rethinking the secrecy outage formulation a secure transmission design perspective"
    - "cooperative jamming for secure communications in mimo relay networks"

Connected through hyperedge HE-2 (induced by source paper "enhancing physical layer security in af relay assisted multicarrier wireless transmission enhancing physical layer security in af relay assisted multicarrier wireless transmission"):
  with members:
    - "ofdma based df secure cooperative communication with untrusted users"
    - "enhancing physical layer security in dual hop multiuser transmission"
    - "secure communication via an untrusted non regenerative relay in fading channels"
    - "power and subcarrier allocation for physical layer security in ofdma based broadband wireless networks"

Connected through hyperedge HE-3 (induced by source paper "secure transmission in linear multihop relaying networks"):
  with members:
    - "secure routing in multihop wireless ad hoc networks with decode and forward relaying"
    - "asymptotic deployment gain a simple approach to characterize the sinr distribution in general cellular networks"
    - "when does relay transmission give a more secure connection in wireless ad hoc networks"
    - "an upper bound on multihop transmission capacity with dynamic routing selection"
    - "rethinking the secrecy outage formulation a secure transmission design perspective"
    - "on the throughput cost of physical layer security in decentralized wireless networks"
    - "outage probability of general ad hoc networks in the high reliability regime"
    - "random access transport capacity"

Connected through hyperedge HE-4 (induced by source paper "physical layer security aware routing and performance tradeoffs in ad hoc networks"):
  with members:
    - "secure routing in multihop wireless ad hoc networks with decode and forward relaying"
    - "relay selection improves the security reliability trade off in cognitive radio systems"
    - "secure degrees of freedom of one hop wireless networks"
    - "security versus reliability analysis of opportunistic relaying"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "on the throughput cost of physical layer security in decentralized wireless networks"
    - "an overview of the transmission capacity of wireless networks"

Connected through hyperedge HE-5 (induced by source paper "secrecy rate maximization with outage constraint in multihop relaying networks"):
  with members:
    - "energy efficient routing in wireless networks in the presence of jamming"
    - "physical layer security of a buffer aided full duplex relaying system"
    - "secure routing in multihop wireless ad hoc networks with decode and forward relaying"
    - "artificial noise aided secrecy information and power transfer in ofdma systems"
    - "energy harvesting for physical layer security in ofdma networks"
    - "when does relay transmission give a more secure connection in wireless ad hoc networks"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "rethinking the secrecy outage formulation a secure transmission design perspective"

Connected through hyperedge HE-6 (induced by source paper "secure routing in multihop wireless ad hoc networks with decode and forward relaying"):
  with members:
    - "when does relay transmission give a more secure connection in wireless ad hoc networks"
    - "physical layer security in downlink multi antenna cellular networks"
    - "secure beamforming for mimo two way communications with an untrusted relay"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "physical layer security in cellular networks a stochastic geometry approach"
    - "on cooperative relaying schemes for wireless physical layer security"
    - "on the throughput cost of physical layer security in decentralized wireless networks"

Connected through hyperedge HE-7 (induced by source paper "physical layer security aware routing and performance tradeoffs in wanets"):
  with members:
    - "secure routing in multihop wireless ad hoc networks with decode and forward relaying"
    - "secure degrees of freedom of one hop wireless networks"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "on the throughput cost of physical layer security in decentralized wireless networks"
    - "an overview of the transmission capacity of wireless networks"
    - "the secrecy capacity of the mimo wiretap channel"

Connected through hyperedge HE-8 (induced by source paper "secure communications in the presence of a buffer aided wireless powered relay with self energy recycling"):
  with members:
    - "full duplex wireless powered relay with self energy recycling"
    - "wireless information and power transfer with full duplex relaying"
    - "relaying protocols for wireless energy harvesting and information processing"

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)