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: "generative growth model for power grids"
  Abstract: The inherent structure of the power grid deeply influences its secure functioning and stability. As power grids move towards becoming `smarter' with increased demand response and decentralized control, the topological aspects of the grid have become even more important. Understanding the topology can thus lead to better strategies to control the smart grid as well as enable rapid identification and prevention of risks such as blackouts. This paper focuses on modeling and analyzing basic similarities in network structure of large power grids across America and Europe. A simple but accurate model of the power grid can help generate real-sized test cases to evaluate new grid technologies as well as aid in tractable theoretical analysis of the grid structure.

Connected through hyperedge HE-1 (induced by source paper "structural vulnerability of power grids to disasters bounds adversarial attacks and reinforcement"):
  with members:
    - "optimal topology design for disturbance minimization in power grids"
    - "an interaction model for simulation and mitigation of cascading failures"
    - "power grid vulnerability to geographically correlated failures analysis and control implications"
    - "cascading link failure in the power grid a percolation based analysis"

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.SI(Social and Information Networks)