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: "caching improvement using adaptive user clustering"
  Abstract: In this article we explore one of the most promising technologies for 5G wireless networks using an underlay small cell network, namely proactive caching. Using the increase in storage technologies and through studying the users behavior, peak traffic can be reduced through proactive caching of the content that is most probable to be requested. We propose a new method, in which, instead of caching the most popular content, the users within the network are clustered according to their content popularity and the caching is done accordingly. We present also a method for estimating the number of clusters within the network based on the Akaike information criterion. We analytically derive a closed form expression of the hit probability and we propose an optimization problem in which the small base stations association with clusters is optimized.

Connected through hyperedge HE-1 (induced by source paper "energy efficiency in cache enabled small cell networks with adaptive user clustering"):
  with members:
    - "caching in the sky proactive deployment of cache enabled unmanned aerial vehicles for optimized quality of experience"
    - "cluster content caching an energy efficient approach to improve quality of service in cloud radio access networks"
    - "energy efficiency of downlink networks with caching at base stations"
    - "greendelivery proactive content caching and push with energy harvesting based small cells"
    - "on the benefits of edge caching for mimo interference alignment"
    - "optimal geographic caching in cellular networks"
    - "caching at the edge a green perspective for 5g networks"
    - "modeling and analysis of content caching in wireless small cell networks"

Connected through hyperedge HE-2 (induced by source paper "echo state networks for proactive caching in cloud based radio access networks with mobile users"):
  with members:
    - "echo state networks for self organizing resource allocation in lte u with uplink downlink decoupling"
    - "joint millimeter wave fronthaul and ofdma resource allocation in ultra dense cran"
    - "optimal fronthaul quantization for cloud radio positioning"
    - "recent advances in cloud radio access networks system architectures key techniques and open issues"
    - "octopus a cooperative hierarchical caching strategy for cloud radio access networks"
    - "joint wireless fronthaul and ofdma resource allocation in ultra dense cran"
    - "mobility aware caching for content centric wireless networks modeling and methodology"
    - "cluster content caching an energy efficient approach to improve quality of service in cloud radio access networks"

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)