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: "distributed load side control coping with variation of renewable generations"
  Abstract: This paper addresses the distributed load frequency control of multi-area power system, where controllable loads are utilized to recover nominal frequencies for the advantage of fast response speed. The imbalanced power causing frequency deviation is decomposed into three parts: a known constant part, an unknown low-frequency variation part and a high-frequency residual. The known steady part is usually the prediction of power imbalance. The variation may result from the fluctuation of renewable resources, electric vehicle charging, etc., which is usually unknown to operators. The high-frequency residual is usually unknown and treated as an external disturbance. Correspondingly, in this paper, we resolve the following three problems in different timescales: 1) allocate the steady part of power imbalance economically; 2) mitigate the effect of unknown low-frequency power variation locally; 3) attenuate unknown high-frequency disturbances. To this end, a distributed controller combining consensus method with adaptive internal model control is proposed. We first prove that the closed-loop system is asymptotically stable and converges to the optimal solution of an optimization counterpart problem if the external disturbance is not included. We then prove that the power variation can be mitigated accurately. Furthermore, we show the closed-loop system is robust against both parameter uncertainty and external disturbances. The New England system is used to verifiy the efficacy of our design.

Connected through hyperedge HE-1 (induced by source paper "distributed optimal load frequency control considering nonsmooth cost functions"):
  with members:
    - "distributed optimal frequency control considering a nonlinear network preserving model"

Connected through hyperedge HE-2 (induced by source paper "asynchronous distributed power control of multi microgrid systems based on the operator splitting approach"):
  with members:
    - "distributed optimal frequency control considering a nonlinear network preserving model"

Connected through hyperedge HE-3 (induced by source paper "distributed control of hybrid ac dc microgrids from synchronous to asynchronous algorithms"):
  with members:
    - "distributed optimal frequency control considering a nonlinear network preserving model"

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.SY(Systems and Control)