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: "an improved vulnerability index of complex networks based on fractal dimension"
  Abstract: AbstractWith an increasing emphasis on network security, much more attention hasbeen attracted to the vulnerability of complex networks. The multi-scaleevaluation of vulnerability is widely used since it makes use of combinedpowers of the links’ betweenness and has an eﬀective evaluation to vulner-ability. However, how to determine the coeﬃcient in existing multi-scaleevaluation model to measure the vulnerability of diﬀerent networks is still anopen issue. In this paper, an improved model based on the fractal dimensionof complex networks is proposed to obtain a more reasonable evaluation ofvulnerability with more physical signiﬁcance. Not only the structure andbasic physical properties of networks is characterized, but also the coveringability of networks, which is related to the vulnerability of the network, istaken into consideration in our proposed method. The numerical examples 1 Corresponding author: Yong Deng, School of Computer and Information Science,Southwest University, Chongqing, 400715, China. Email address: ydeng@swu.edu.cn;prof.deng@hotmail.comPreprintsubmittedtoSafetyScience June5,2014

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.SI(Social and Information Networks)