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: "a day ahead market energy auction for distribution system operation"
  Abstract: In this paper, we study a Day-ahead Market(DAM) double energy auction in a distribution system involving dispatchable generation units, renewable generation units supported by battery storage systems(BSSs), fixed loads, price responsive loads, and supply from the Wholesale Market(WSM) at Locational Marginal Price (LMP). The auction is implemented within a Distribution System Operator (DSO) premises using Mixed Integer Linear Programming (MILP). The proposed auction is cleared at the Distribution LMP (DLMP) and is observed to be weakly budget balanced if no penalty is applied for DSO's deviation from its original commitment with the WSM. Furthermore, the dynamics of DLMP versus LMP, and their effect on distribution market participants scheduled quantities as well as the WSM supply to the distribution system is investigated.

Connected through hyperedge HE-1 (induced by source paper "distributed bilevel energy allocation mechanism with grid constraints and hidden user information"):
  with members:
    - "an iterative on line auction mechanism for aggregated demand side participation"
    - "distribution market clearing and settlement"
    - "prioritizing consumers in smart grid a game theoretic approach"
    - "a game theoretic approach to energy trading in the smart grid"

Connected through hyperedge HE-2 (induced by source paper "renewable energy integration in distribution system synchrophasor sensor based big data analysis visualization and system operation"):
  with members:
    - "power traffic coordinated operation for bi peak shaving and bi ramp smoothing a hierarchical data driven approach"
    - "chance constrained day ahead hourly scheduling in distribution system operation"
    - "load forecasting based distribution system network reconfiguration a distributed data driven approach"

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)