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: "chance constrained day ahead hourly scheduling in distribution system operation"
  Abstract: This paper aims to propose a two-step approach for day-ahead hourly scheduling in a distribution system operation, which contains two operation costs, the operation cost at substation level and feeder level. In the first step, the objective is to minimize the electric power purchase from the day-ahead market with the stochastic optimization. The historical data of day-ahead hourly electric power consumption is used to provide the forecast results with the forecasting error, which is presented by a chance constraint and formulated into a deterministic form by Gaussian mixture model (GMM). In the second step, the objective is to minimize the system loss. Considering the nonconvexity of the three-phase balanced AC optimal power flow problem in distribution systems, the second-order cone program (SOCP) is used to relax the problem. Then, a distributed optimization approach is built based on the alternating direction method of multiplier (ADMM). The results shows that the validity and effectiveness method.

Connected through hyperedge HE-1 (induced by source paper "multi agent reinforcement learning embedded game for the optimization of building energy control and power system planning"):
  with members:
    - "flexible energy management protocol for cooperative ev to ev charging"
    - "autonomous and connected intersection crossing traffic management using discrete time occupancies trajectory"

Connected through hyperedge HE-2 (induced by source paper "safe and efficient intersection control of connected and autonomous intersection traffic"):
  with members:
    - "autonomous and connected intersection crossing traffic management using discrete time occupancies trajectory"
    - "power traffic coordinated operation for bi peak shaving and bi ramp smoothing a hierarchical data driven approach"
    - "load forecasting based distribution system network reconfiguration a distributed data driven approach"
    - "polling systems based autonomous vehicle coordination in traffic intersections with no traffic signals"
    - "a market inspired approach for intersection management in urban road traffic networks"

Connected through hyperedge HE-3 (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"
    - "load forecasting based distribution system network reconfiguration a distributed data driven approach"
    - "a day ahead market energy auction for distribution system operation"

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)