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 user association and spectrum allocation in hetnets a utility perspective"
  Abstract: The joint user association and spectrum allocation problem is studied for multi-tier heterogeneous networks (HetNets) in both downlink and uplink in the interference-limited regime. Users are associated with base-stations (BSs) based on the biased downlink received power. Spectrum is either shared or orthogonally partitioned among the tiers. This paper models the placement of BSs in different tiers as spatial point processes and adopts stochastic geometry to derive the theoretical mean proportionally fair utility of the network based on the coverage rate. By formulating and solving the network utility maximization problem, the optimal user association bias factors and spectrum partition ratios are analytically obtained for the multi-tier network. The resulting analysis reveals that the downlink and uplink user associations do not have to be symmetric. For uplink under spectrum sharing, if all tiers have the same target signal-to-interference ratio (SIR), distance-based user association is shown to be optimal under a variety of path loss and power control settings. For both downlink and uplink, under orthogonal spectrum partition, it is shown that the optimal proportion of spectrum allocated to each tier should match the proportion of users associated with that tier. Simulations validate the analytical results. Under typical system parameters, simulation results suggest that spectrum partition performs better for downlink in terms of utility, while spectrum sharing performs better for uplink with power control.

Connected through hyperedge HE-1 (induced by source paper "resource allocation in green dense cellular networks complexity and algorithms"):
  with members:
    - "large scale spectrum allocation for cellular networks via sparse optimization"
    - "optimal user scheduling in energy harvesting wireless networks"
    - "scalable spectrum allocation and user association in networks with many small cells"
    - "boost base station on off switching strategy for energy efficient massive mimo hetnets"
    - "online ski rental for on off scheduling of energy harvesting base stations"
    - "online energy efficient packet scheduling for a common deadline with and without energy harvesting"
    - "gate greening at the edges"
    - "energy efficient cell activation user association and spectrum allocation in heterogeneous networks"

Connected through hyperedge HE-2 (induced by source paper "dynamic spectrum sharing for load balancing in multi cell mobile edge computing"):
  with members:
    - "joint service placement and request routing in multi cell mobile edge computing networks"
    - "mobile edge computing enabled heterogeneous networks"
    - "multiuser computation offloading and downloading for edge computing with virtualization"
    - "joint optimization of radio and computational resources for multicell mobile edge computing"
    - "efficient multi user computation offloading for mobile edge cloud computing"
    - "user association for load balancing in heterogeneous cellular networks"

Connected through hyperedge HE-3 (induced by source paper "energy efficient massive iot shared spectrum access over uav enabled cellular networks"):
  with members:
    - "cellular connected uav uplink association power control and interference coordination"
    - "performance analysis of uplink cellular iot using different deployments of data aggregators"
    - "aeronautical data aggregation and field estimation in iot networks hovering traveling time dilemma of uavs"
    - "mobile unmanned aerial vehicles uavs for energy efficient internet of things communications"
    - "on the energy distortion tradeoff in the iot"
    - "energy efficient data collection in uav enabled wireless sensor network"
    - "energy efficient uav communication with trajectory optimization"
    - "energy efficient power control a look at 5g wireless technologies"

Connected through hyperedge HE-4 (induced by source paper "impact of end user behavior on user network association in hetnets"):
  with members:
    - "user association in 5g networks a survey and an outlook"
    - "prospect pricing in cognitive radio networks"

Connected through hyperedge HE-5 (induced by source paper "the stochastic geometry analyses of cellular networks with alpha stable self similarity"):
  with members:
    - "system level modeling and optimization of the energy efficiency in cellular networks a stochastic geometry framework"
    - "delivery secrecy tradeoff for cache enabled stochastic networks content placement optimization"
    - "self interference in full duplex multi user mimo channels"
    - "secrecy outage analysis for downlink transmissions in the presence of randomly located eavesdroppers"
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "analytical modeling of interference aware power control for the uplink of heterogeneous cellular networks"
    - "analysis of massive mimo enabled downlink wireless backhauling for full duplex small cells"
    - "the learning and prediction of application level traffic data in cellular networks"

Connected through hyperedge HE-6 (induced by source paper "physical layer security in heterogeneous networks with jammer selection and full duplex users"):
  with members:
    - "exploiting full duplex receivers for achieving secret communications in multiuser miso networks"
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "hybrid duplex switching in heterogeneous networks"
    - "opportunistic jamming for enhancing security stochastic geometry modeling and analysis"
    - "physical layer security in millimeter wave cellular networks"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "physical layer security in heterogeneous cellular networks"
    - "secure communication in uplink transmissions user selection and multiuser secrecy gain"

Connected through hyperedge HE-7 (induced by source paper "distributed user association in energy harvesting small cell networks a probabilistic bandit model"):
  with members:
    - "multi armed bandits with application to 5g small cells"
    - "user association in 5g networks a survey and an outlook"
    - "multi access communications with energy harvesting a multi armed bandit model and the optimality of the myopic policy"
    - "cooperative interference mitigation and handover management for heterogeneous cloud small cell networks"
    - "channel selection for network assisted d2d communication via no regret bandit learning with calibrated forecasting"
    - "a context aware matching game for user association in wireless small cell networks"
    - "matching theory for priority based cell association in the downlink of wireless small cell networks"
    - "a traffic load balancing framework for software defined radio access networks powered by hybrid energy sources"

Connected through hyperedge HE-8 (induced by source paper "delay optimal biased user association in heterogeneous networks"):
  with members:
    - "random cell association and void probability in poisson distributed cellular networks"
    - "optimal base station deployment for small cell networks with energy efficient power control"
    - "traffic driven spectrum allocation in heterogeneous networks"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "what will 5g be"
    - "joint resource partitioning and offloading in heterogeneous cellular networks"
    - "offloading in heterogeneous networks modeling analysis and design insights"
    - "load aware modeling and analysis of heterogeneous cellular 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)