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: "designing constraint based false data injection attacks for unbalanced distribution smart grids"
  Abstract: Smart grid is equipped with various kinds of smart devices such as meters, sensors, and actuators, to name a few, and it can be characterized as the Internet of Things. The cyber domain of this cyber-physical system also has to deal with many cyber-threats, including the stealthy False Data Injection (FDI) attack. This man-in-the-middle data-driven attack is extremely dangerous due to its ability to disrupt the operation without being detected. The unbalanced distribution network is a highly probable target for an FDI attack due to its easy physical access. This paper will investigate an attack design scheme based on a nonlinear physical-constraint model that is able to produce an FDI attack with the same theoretical stealthy characteristic. To demonstrate the effectiveness of the proposed design scheme, simulations with the IEEE 13-node Test Feeder are conducted. The experimental results indicate that the false positive rate of the bad data detection mechanism is 100\%. This figurative number opens a serious challenge for operators in maintaining the integrity of measurement data.

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.CR(Cryptography and Security)