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: "hierarchical grid based pairwise key pre distribution in wireless sensor networks"
  Abstract: The security of wireless sensor networks is an active topic of research where both symmetric and asymmetric key cryptography issues have been studied. Due to their computational feasibility on typical sensor nodes, symmetric key algorithms that use the same key to encrypt and decrypt messages have been intensively studied and perfectly deployed in such environment. Because of the wireless sensor's limited infrastructure, the bottleneck challenge for deploying these algorithms is the key distribution. For the same reason of resources restriction, key distribution mechanisms which are used in traditional wireless networks are not efficient for sensor networks. #R##N#To overcome the key distribution problem, several key pre-distribution algorithms and techniques that assign keys or keying material for the networks nodes in an offline phase have been introduced recently. In this paper, we introduce a supplemental distribution technique based on the communication pattern and deployment knowledge modeling. Our technique is based on the hierarchical grid deployment. For granting a proportional security level with number of dependent sensors, we use different polynomials in different orders with different weights. In seek of our proposed work's value, we provide a detailed analysis on the used resources, resulting security, resiliency, and connectivity compared with other related works.

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)