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: "optimizing client association in 60 ghz wireless access networks"
  Abstract: MillimeterWave communications in the 60 GHz band are considered one of the key technologies for enabling multi-gigabit wireless access. However, the high propagation loss in such a band poses major obstacles to the optimal utilization of the wireless resources, where the problem of efficient client association to access points (APs) is of vital importance. In this paper, the client association in 60 GHz wireless access networks is investigated. The AP utilization and the quality of the rapidly vanishing communication links are the control parameters. Because of the tricky non-convex and combinatorial nature of the client association optimization problem, a novel solution method is developed to guarantee balanced and fair resource allocation. A new distributed, lightweight and easy to implement association algorithm, based on Lagrangian duality theory and subgradient methods, was proposed. It is shown that the algorithm is asymptotically optimal, that is, the relative duality gap diminishes to zero as the number of clients increases. Both theoretical and numerical results evince numerous useful properties of the algorithm, such as fast convergence, scalability, time efficiency, and fair execution in comparison to existing approaches. It is concluded that the proposed solution can be applied in the forthcoming 60 GHz wireless access networks.

Connected through hyperedge HE-1 (induced by source paper "a hybrid model based and data driven approach to spectrum sharing in mmwave cellular networks"):
  with members:
    - "how to escape saddle points efficiently"
    - "modeling infrastructure sharing in mmwave networks with shared spectrum licenses"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "subspace estimation and decomposition for large millimeter wave mimo systems"
    - "spectrum sharing in mmwave cellular networks via cell association coordination and beamforming"
    - "sum rate maximization in sub 28 ghz millimeter wave mimo interfering networks"
    - "stochastic geometry modeling and analysis of multi tier millimeter wave cellular networks"
    - "the transitional behavior of interference in millimeter wave networks and its impact on medium access control"

Connected through hyperedge HE-2 (induced by source paper "spectrum sharing in mmwave cellular networks via cell association coordination and beamforming"):
  with members:
    - "downlink and uplink cell association with traditional macrocells and millimeter wave small cells"
    - "on the accuracy of interference models in wireless communications"
    - "distributed association and relaying with fairness in millimeter wave networks"
    - "spectrum pooling in mmwave networks opportunities challenges and enablers"
    - "towards an appropriate receiver beamforming scheme for millimeter wave communication a power consumption based comparison"
    - "hybrid spectrum access for mmwave networks"
    - "stochastic geometry modeling and analysis of multi tier millimeter wave cellular networks"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-3 (induced by source paper "distributed association and relaying with fairness in millimeter wave networks"):
  with members:
    - "beam searching and transmission scheduling in millimeter wave communications"
    - "millimeter wave cellular networks a mac layer perspective"
    - "the transitional behavior of interference in millimeter wave networks and its impact on medium access control"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "unified and distributed qos driven cell association algorithms in heterogeneous networks"
    - "what will 5g be"
    - "millimeter wave cellular wireless networks potentials and challenges"

Connected through hyperedge HE-4 (induced by source paper "millimeter wave cellular networks a mac layer perspective"):
  with members:
    - "stochastic geometry modeling and analysis of multi tier millimeter wave cellular networks"
    - "beam searching and transmission scheduling in millimeter wave communications"
    - "a survey of millimeter wave mmwave communications for 5g opportunities and challenges"
    - "subspace estimation and decomposition for hybrid analog digital millimetre wave mimo systems"
    - "design aspects of short range millimeter wave networks a mac layer perspective"
    - "on the joint impact of beamwidth and orientation error on throughput in directional wireless poisson networks"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-5 (induced by source paper "optimal user cell association for massive mimo wireless networks"):
  with members:
    - "an overview of load balancing in hetnets old myths and open problems"
    - "distributed linear precoder optimization and base station selection for an uplink heterogeneous network"
    - "scalable synchronization and reciprocity calibration for distributed multiuser mimo"
    - "joint spatial division and multiplexing for mm wave channels"
    - "downlink multi antenna heterogeneous cellular network with load balancing"
    - "network mimo with linear zero forcing beamforming large system analysis impact of channel estimation and reduced complexity scheduling"
    - "user association for load balancing in heterogeneous cellular networks"
    - "achieving massive mimo spectral efficiency with a not so large number of antennas"

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.NI(Networking and Internet Architecture)