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: "73 ghz wideband millimeter wave foliage and ground reflection measurements and models"
  Abstract: This paper presents 73 GHz wideband outdoor foliage and ground reflection measurements. Propagation measurements were made with a 400 Megachips-per-second sliding correlator channel sounder, with rotatable 27 dBi (7° half-power beamwidth) horn antennas at both the transmitter and receiver, to study foliage-induced scattering and de-polarization effects, to assist in developing future wireless systems that will use adaptive array antennas. Signal attenuation through foliage was measured to be 0.4 dB/m for both co- and cross-polarized antenna configurations. Measured ground reflection coefficients for dirt and gravel ranged from 0.02 to 0.34, for incident angles ranging from 60° to 81° (with respect to the normal incidence of the surface). These data are useful for link budget design and site-specific (ray-tracing) models for future millimeter-wave communications systems.

Connected through hyperedge HE-1 (induced by source paper "verification and calibration of antenna cross polarization discrimination and penetration loss for millimeter wave communications"):
  with members:
    - "indoor office wideband penetration loss measurements at 73 ghz"

Connected through hyperedge HE-2 (induced by source paper "overview of millimeter wave communications for fifth generation 5g wireless networks with a focus on propagation models"):
  with members:
    - "indoor office wideband penetration loss measurements at 73 ghz"
    - "study on 3gpp rural macrocell path loss models for millimeter wave wireless communications"
    - "investigation and comparison of 3gpp and nyusim channel models for 5g wireless communications"
    - "millimeter wave small scale spatial statistics in an urban microcell scenario"
    - "a novel millimeter wave channel simulator and applications for 5g wireless communications"
    - "small scale local area and transitional millimeter wave propagation for 5g communications"
    - "5g 3gpp like channel models for outdoor urban microcellular and macrocellular environments"
    - "millimeter wave human blockage at 73 ghz with a simple double knife edge diffraction model and extension for directional antennas"

Connected through hyperedge HE-3 (induced by source paper "statistical channel model with multi frequency and arbitrary antenna beamwidth for millimeter wave outdoor communications"):
  with members:
    - "a prediction study of path loss models from 2 73 5 ghz in an urban macro environment"
    - "propagation path loss models for 5g urban micro and macro cellular scenarios"
    - "3 d statistical channel model for millimeter wave outdoor mobile broadband communications"

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)