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 random access and random spectrum sensing for an energy harvesting cognitive radio"
  Abstract: We consider a secondary user with energy harvesting capability. We design access schemes for the secondary user which incorporate random spectrum sensing and random access, and which make use of the primary automatic repeat request (ARQ) feedback. The sensing and access probabilities are obtained such that the secondary throughput is maximized under the constraints that both the primary and secondary queues are stable and that the primary queueing delay is kept lower than a specified value needed to guarantee a certain quality of service (QoS) for the primary user. We consider spectrum sensing errors and assume multipacket reception (MPR) capabilities. Numerical results are presented to show the enhanced performance of our proposed system over a random access system, and to demonstrate the benefit of leveraging the primary feedback.

Connected through hyperedge HE-1 (induced by source paper "on energy cooperation in energy harvesting underlay cognitive radio network"):
  with members:
    - "optimal time sharing in underlay cognitive radio systems with rf energy harvesting"
    - "on information and energy cooperation in energy harvesting cognitive radio"
    - "information and energy cooperation in cognitive radio networks"
    - "energy harvesting cognitive radio with channel aware sensing strategy"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "on green energy powered cognitive radio networks"
    - "cognitive energy harvesting and transmission from a network perspective"
    - "optimal utilization of a cognitive shared channel with a rechargeable primary source node"

Connected through hyperedge HE-2 (induced by source paper "optimal spectrum access for a rechargeable cognitive radio user based on energy buffer state"):
  with members:
    - "dynamic spectrum access in cognitive radio networks with rf energy harvesting"
    - "on spectrum sharing between energy harvesting cognitive radio users and primary users"
    - "power optimal feedback based random spectrum access for an energy harvesting cognitive user"
    - "on the coexistence of a primary user with an energy harvesting secondary user a case of cognitive cooperation"
    - "optimal selection of spectrum sensing duration for an energy harvesting cognitive radio"
    - "cooperative cognitive relaying with ordered cognitive multiple access"
    - "green cellular networks a survey some research issues and challenges"
    - "optimal utilization of a cognitive shared channel with a rechargeable primary source node"

Connected through hyperedge HE-3 (induced by source paper "on spectrum sharing between energy harvesting cognitive radio users and primary users"):
  with members:
    - "dynamic spectrum access in cognitive radio networks with rf energy harvesting"
    - "on the coexistence of a primary user with an energy harvesting secondary user a case of cognitive cooperation"
    - "opportunistic wireless energy harvesting in cognitive radio networks"
    - "optimal selection of spectrum sensing duration for an energy harvesting cognitive radio"
    - "green cellular networks a survey some research issues and challenges"
    - "optimal utilization of a cognitive shared channel with a rechargeable primary source node"
    - "optimum transmission policies for battery limited energy harvesting nodes"
    - "optimal packet scheduling in an energy harvesting communication system"

Connected through hyperedge HE-4 (induced by source paper "power optimal feedback based random spectrum access for an energy harvesting cognitive user"):
  with members:
    - "harvest then cooperate wireless powered cooperative communications"
    - "optimal selection of spectrum sensing duration for an energy harvesting cognitive radio"
    - "optimal utilization of a cognitive shared channel with a rechargeable primary source node"
    - "cognitive interference management in retransmission based wireless networks"
    - "optimum transmission policies for battery limited energy harvesting nodes"
    - "optimal packet scheduling in an energy harvesting communication system"
    - "optimal energy management policies for energy harvesting sensor nodes"

Connected through hyperedge HE-5 (induced by source paper "optimal random access and random spectrum sensing for an energy harvesting cognitive radio with and without primary feedback leveraging"):
  with members:
    - "optimal selection of spectrum sensing duration for an energy harvesting cognitive radio"
    - "optimal utilization of a cognitive shared channel with a rechargeable primary source node"
    - "cognitive interference management in retransmission based wireless networks"
    - "optimum transmission policies for battery limited energy harvesting nodes"
    - "optimal energy management policies for energy harvesting sensor nodes"

Connected through hyperedge HE-6 (induced by source paper "optimal cooperative cognitive relaying and spectrum access for an energy harvesting cognitive radio reinforcement learning approach"):
  with members:
    - "comments on optimal utilization of a cognitive shared channel with a rechargeable primary source node"
    - "on the coexistence of a primary user with an energy harvesting secondary user a case of cognitive cooperation"
    - "optimal utilization of a cognitive shared channel with a rechargeable primary source node"
    - "optimal energy management policies for energy harvesting sensor nodes"

Connected through hyperedge HE-7 (induced by source paper "maximum throughput of a cooperative energy harvesting cognitive radio user"):
  with members:
    - "optimal selection of spectrum sensing duration for an energy harvesting cognitive radio"
    - "optimal utilization of a cognitive shared channel with a rechargeable primary source node"
    - "optimal energy management policies for energy harvesting sensor nodes"

Connected through hyperedge HE-8 (induced by source paper "relay assisted primary and secondary transmissions"):
  with members:
    - "cooperative cognitive relaying with ordered cognitive multiple access"
    - "buffers improve the performance of relay selection"

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)