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: "ieee 802 15 6 based prototype system for wban design and implementation"
  Abstract: Various current trends such as ever growing population and accelerated aging effects have effectively promoted the growth of Wireless Body Area Network (WBAN). Being the specialized standard of WBAN, the burgeoning IEEE 802.15.6 is on its way to refinement and perfection. Since experiments are the foundation of research in WBAN that reproduce system operating patterns, yet existing platforms in WBAN are mainly simulations that could not highly conform to reality with strict requirements to some degree. Thus, a reliable and efficient system based on the IEEE 802.15.6, named WBAN prototype system, is proposed and implemented in this paper. The prototype system is ascertained to be valid, authentic and efficient via analyses of scenario tests. Running in circumstances much closer to reality, the system obtains experimental results that meet rigid requirements preferably. Furthermore, based on the valid platform we created, optimizations of two parameters in the IEEE 802.15.6 by actual measurements are derived. We obtain an optimum number of transmission retries and relationship of payload length within 30 with FER, making a trade-off between waste of resource and high packet loss rate.

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.NI(Networking and Internet Architecture)