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: "secure relaying in non orthogonal multiple access trusted and untrusted scenarios"
  Abstract: A downlink single-input single-output non-orthogonal multiple access setting is considered, in which a base station (BS) is communicating with two legitimate users in two possible scenarios of unsecure environments: existence of an external eavesdropper and communicating through an  untrusted  relay. For the first scenario, a number of  trusted  cooperative half-duplex relays is employed to assist with the BS’s transmission and secure its signals from the external eavesdropper. Various relaying schemes are proposed and analyzed for that matter:  cooperative jamming ,  decode-and-forward , and  amplify-and-forward . For each scheme,  secure beamforming  signals are devised at the relays to maximize the achievable secrecy rate regions. For the second scenario, with the untrusted relay, achievable secrecy rate regions are derived for two different relaying schemes,  compress-and-forward  and  amplify-and-forward , under two different modes of operation. In the first mode, coined  passive user  mode, the users receive signals from both the BS and the untrusted relay and combine them to decode their messages. In the second mode, termed the  active user  mode, the users transmit a cooperative jamming signal  simultaneously  with the BS’s transmission to further confuse the relay. Focusing on half-duplex nodes, the users cannot receive the BS’s signal while jamming the relay, i.e., while being active, and rely only on the signals forwarded to them by the relay. It is shown that the best relaying scheme highly depends on the system parameters, in particular the distances between the nodes, and also on the part of the secrecy rate region at which the system is to operate.

Connected through hyperedge HE-1 (induced by source paper "interplay between noma and other emerging technologies a survey"):
  with members:
    - "securing downlink massive mimo noma networks with artificial noise"
    - "lens based millimeter wave reconfigurable antenna noma"
    - "what role can noma play in massive mimo"
    - "noma an information theoretic perspective"
    - "joint power and time allocation for noma mec offloading"
    - "multi beam noma for hybrid mmwave systems"
    - "exploiting full half duplex user relaying in noma systems"
    - "energy efficient noma enabled heterogeneous cloud radio access networks"

Connected through hyperedge HE-2 (induced by source paper "secrecy outage analysis for cooperative noma systems with relay selection scheme"):
  with members:
    - "secure transmission to the strong user with optimal power allocation in noma"
    - "multiple antenna assisted non orthogonal multiple access"
    - "spatially random relay selection for full half duplex cooperative noma networks"
    - "non orthogonal multiple access for cooperative communications challenges opportunities and trends"
    - "secure communications in noma system subcarrier assignment and power allocation"
    - "state of the art taxonomy and open issues on cognitive radio networks with noma"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"

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)