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: "optimal joint user association and resource allocation in heterogeneous networks via sparsity pursuit"
  Abstract: This paper studies the joint user association and resource allocation in heterogeneous networks (HetNets) from a novel perspective, motivated by and generalizing the idea of fractional frequency reuse. By treating the multi-cell multi-user resource allocation as resource partitioning among multiple reuse patterns, we propose a unified framework to analyze and compare a wide range of user association and resource allocation strategies for HetNets, and provide an optimal benchmark for network performance. The enabling mechanisms are a novel formulation to consider all possible interference patterns or any pre-defined subset of patterns, and efficient sparsity-pursuit algorithms to find the solution. A notable feature of this formulation is that the patterns remain fixed during the resource optimization process. This creates a favorable opportunity for convex formulations while still considering interference coupling. More importantly, in view of the fact that multi-cell resource allocation is very computational demanding, our framework provides a systematic way to trade off performance for the reduction of computational complexity by restricting the candidate patterns to a small number of feature patterns. Relying on the sparsity-pursuit capability of the proposed algorithms, we develop a practical guideline to identify the feature patterns. Numerical results show that the identified feature patterns can significantly improve the existing strategies, and jointly optimizing the user association and resource allocation indeed brings considerable gain.

Connected through hyperedge HE-1 (induced by source paper "energy management in heterogeneous networks with cell activation user association and interference coordination"):
  with members:
    - "network topology adaptation and interference coordination for energy saving in heterogeneous networks"
    - "energy efficient cell activation user association and spectrum allocation in heterogeneous networks"
    - "traffic driven spectrum allocation in heterogeneous networks"
    - "base station activation and linear transceiver design for optimal resource management in heterogeneous networks"
    - "joint user association and reuse pattern selection in heterogeneous networks"
    - "group sparse beamforming for green cloud ran"
    - "base station selection for energy efficient network operation with the majorization minimization algorithm"
    - "user association for load balancing in heterogeneous cellular networks"

Connected through hyperedge HE-2 (induced by source paper "dual timescale spectrum management in wireless heterogeneous networks"):
  with members:
    - "energy management in heterogeneous networks with cell activation user association and interference coordination"
    - "energy efficient cell activation user association and spectrum allocation in heterogeneous networks"
    - "traffic driven spectrum allocation in heterogeneous networks"
    - "algorithms for enhanced inter cell interference coordination eicic in lte hetnets"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "base station activation and linear transceiver design for optimal resource management in heterogeneous networks"
    - "user association for load balancing in heterogeneous cellular networks"

Connected through hyperedge HE-3 (induced by source paper "energy efficient cell activation user association and spectrum allocation in heterogeneous networks"):
  with members:
    - "energy management in heterogeneous networks with cell activation user association and interference coordination"
    - "licensed and unlicensed spectrum allocation in heterogeneous networks"
    - "traffic driven spectrum allocation in heterogeneous networks"
    - "base station selection for energy efficient network operation with the majorization minimization algorithm"

Connected through hyperedge HE-4 (induced by source paper "traffic driven spectrum allocation in heterogeneous networks"):
  with members:
    - "energy efficient cell activation user association and spectrum allocation in heterogeneous networks"
    - "algorithms for enhanced inter cell interference coordination eicic in lte hetnets"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "what will 5g be"
    - "base station activation and linear transceiver design for optimal resource management in heterogeneous networks"
    - "traffic driven resource allocation in heterogenous wireless networks"
    - "load aware modeling and analysis of heterogeneous cellular networks"
    - "a tractable approach to coverage and rate in 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)