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: "topology detection in microgrids with micro synchrophasors"
  Abstract: Network topology in distribution networks is often unknown, because most switches are not equipped with measurement devices and communication links. However, knowledge about the actual topology is critical for safe and reliable grid operation. This paper proposes a voting-based topology detection method based on micro-synchrophasor measurements. The minimal difference between measured and calculated voltage angle or voltage magnitude, respectively, indicates the actual topology. Micro-synchrophasors or micro-Phasor Measurement Units ({\mu}PMU) are high-precision devices that can measure voltage angle differences on the order of ten millidegrees. This accuracy is important for distribution networks due to the smaller angle differences as compared to transmission networks. For this paper, a microgrid test bed is implemented in MATLAB with simulated measurements from {\mu}PMUs as well as SCADA measurement devices. The results show that topologies can be detected with high accuracy. Additionally, topology detection by voltage angle shows better results than detection by voltage magnitude.

Connected through hyperedge HE-1 (induced by source paper "a survey on state estimation techniques and challenges in smart distribution systems"):
  with members:
    - "review of smart meter data analytics applications methodologies and challenges"
    - "patopa a data driven parameter and topology joint estimation framework in distribution grids"
    - "robust recovery of missing data in electricity distribution systems"
    - "vulnerability analysis and consequences of false data injection attack on power system state estimation"

Connected through hyperedge HE-2 (induced by source paper "vader visualization and analytics for distributed energy resources"):
  with members:
    - "patopa a data driven parameter and topology joint estimation framework in distribution grids"
    - "distribution system topology detection using consumer load and line flow measurements"
    - "outage detection in power distribution networks"
    - "optimal inverter var control in distribution systems with high pv penetration"

Connected through hyperedge HE-3 (induced by source paper "micro synchrophasors for power distribution monitoring a technology review"):
  with members:
    - "data driven approach for distribution network topology detection"
    - "phase identification in distribution networks with micro synchrophasors"

Connected through hyperedge HE-4 (induced by source paper "the kirchhoff braess paradox and its implications for smart microgrids"):
  with members:
    - "a packetized direct load control mechanism for demand side management"

Connected through hyperedge HE-5 (induced by source paper "feeder topology identification"):
  with members:
    - "optimal inverter var control in distribution systems with high pv penetration"

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)