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: "smart grid communications overview of research challenges solutions and standardization activities"
  Abstract: Optimization of energy consumption in future intelligent energy networks (or Smart Grids) will be based on grid-integrated near-real-time communications between various grid elements in generation, transmission, distribution and loads. This paper discusses some of the challenges and opportunities of communications research in the areas of smart grid and smart metering. In particular, we focus on some of the key communications challenges for realizing interoperable and future-proof smart grid/metering networks, smart grid security and privacy, and how some of the existing networking technologies can be applied to energy management. Finally, we also discuss the coordinated standardization efforts in Europe to harmonize communications standards and protocols.

Connected through hyperedge HE-1 (induced by source paper "software defined networks based smart grid communication a comprehensive survey"):
  with members:
    - "response time and availability study of raft consensus in distributed sdn control plane"
    - "software defined microgrid control for resilience against cyber attacks"
    - "enabling hard service guarantees in software defined smart grid infrastructures"
    - "survey on network virtualization hypervisors for software defined networking"
    - "an iot architecture for wide area measurement systems a virtualized pmu based approach"
    - "iot cloud based distribution system state estimation virtual objects and context awareness"
    - "network function virtualization state of the art and research challenges"
    - "software defined optical networks sdons a comprehensive survey"

Connected through hyperedge HE-2 (induced by source paper "key management systems for smart grid advanced metering infrastructure a survey"):
  with members:
    - "key management and learning based two level data security for metering infrastructure of smart grid"
    - "minimizing electricity theft using smart meters in ami"

Connected through hyperedge HE-3 (induced by source paper "internet of things aided smart grid technologies architectures applications prototypes and future research directions"):
  with members:
    - "5g mobile cellular networks enabling distributed state estimation for smart grids"
    - "a cloud based and restful internet of things platform to foster smart grid technologies integration and re usability"
    - "an internet of things framework for smart energy in buildings designs prototype and experiments"
    - "context aware computing for the internet of things a survey"
    - "relaying technologies for smart grid communications"
    - "internet of things applications and challenges in technology and standardization"

Connected through hyperedge HE-4 (induced by source paper "decision error probability in a two stage communication network for smart grids with imperfect data links"):
  with members:
    - "average error probability in wireless sensor networks with imperfect sensing and communication for different decision rules"
    - "models for the modern power grid"
    - "for the grid and through the grid the role of power line communications in the smart grid"

Connected through hyperedge HE-5 (induced by source paper "charging electric vehicles in the smart city a survey of economy driven approaches"):
  with members:
    - "charging games in networks of electrical vehicles"
    - "real time welfare maximizing regulation allocation in dynamic aggregator evs system"

Connected through hyperedge HE-6 (induced by source paper "plug and play model predictive control for load shaping and voltage control in smart grids"):
  with members:
    - "plug and play voltage and frequency control of islanded microgrids with meshed topology"

Connected through hyperedge HE-7 (induced by source paper "increasing smart meter privacy through energy harvesting and storage devices"):
  with members:
    - "utility privacy tradeoffs in databases an information theoretic approach"
    - "smart meter privacy a utility privacy framework"

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)