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: "ach away cluster heads scheme for energy efficient clustering protocols in wsns"
  Abstract: This paper deals with the routing protocols for distributed wireless sensor networks. The conventional protocols for WSNs like Low Energy adaptive Clustering Hierarchy (LEACH), Stable Election Protocol (SEP), Threshold Sensitive Energy Efficient Network (TEEN), Distributed Energy Efficient Clustering Protocol (DEEC) may not be optimal. We propose a scheme called Away Cluster Head (ACH) which effectively increases the efficiency of conventional clustering based protocols in terms of stability period and number of packets sent to base station (BS). We have implemented ACH scheme on LEACH, SEP, TEEN and DEEC. Simulation results show that LEACHACH, SEP-ACH, TEEN-ACH and DEEC-ACH performs better than LEACH, SEP, TEEN and DEEC respectively in terms of stability period and number of packets sent to BS. The stability period of the existing protocols prolongs by implementing ACH on them.

Connected through hyperedge HE-1 (induced by source paper "modeling and evaluating performance of routing operations in reactive routing protocols"):
  with members:
    - "evaluating and comparing probability of path loss in dsdv olsr and dymo at 802 11 and 802 11p"
    - "heer hybrid energy efficient reactive protocol for wireless sensor networks"
    - "evaluating wireless reactive routing protocols with linear programming model for wireless ad hoc networks"
    - "on energy efficiency and delay minimization in reactive protocols in wireless multi hop networks"
    - "e horm an energy efficient hole removing mechanism in wireless sensor networks"
    - "density controlled divide and rule scheme for energy efficient routing in wireless sensor networks"
    - "towards lp modeling for maximizing throughput and minimizing routing delay in proactive protocols in wireless multi hop networks"
    - "on adaptive energy efficient transmission in wsns"

Connected through hyperedge HE-2 (induced by source paper "imod leach improved modified leach protocol for wireless sensor networks"):
  with members:
    - "advanced leach a static clustering based heteroneous routing protocol for wsns"
    - "modleach a variant of leach for wsns"
    - "heer hybrid energy efficient reactive protocol for wireless sensor networks"
    - "energy efficient mac protocols in wireless body area sensor networks a survey"
    - "east energy efficient adaptive scheme for transmission in wireless sensor networks"
    - "e horm an energy efficient hole removing mechanism in wireless sensor networks"
    - "density controlled divide and rule scheme for energy efficient routing in wireless sensor networks"
    - "towards lp modeling for maximizing throughput and minimizing routing delay in proactive protocols in wireless multi hop networks"

Connected through hyperedge HE-3 (induced by source paper "amctd adaptive mobility of courier nodes in threshold optimized dbr protocol for underwater wireless sensor networks"):
  with members:
    - "q leach a new routing protocol for wsns"
    - "heer hybrid energy efficient reactive protocol for wireless sensor networks"
    - "on modeling geometric joint sink mobility with delay tolerant cluster less wireless sensor networks"
    - "lpch and udlpch location aware routing techniques in wsns"
    - "e horm an energy efficient hole removing mechanism in wireless sensor networks"
    - "divide and rule scheme for energy efficient routing in wireless sensor networks"
    - "on adaptive energy efficient transmission in wsns"
    - "ceec centralized energy efficient clustering a new routing protocol for wsns"

Connected through hyperedge HE-4 (induced by source paper "m gear gateway based energy aware multi hop routing protocol for wsns"):
  with members:
    - "q leach a new routing protocol for wsns"
    - "heer hybrid energy efficient reactive protocol for wireless sensor networks"
    - "on modeling geometric joint sink mobility with delay tolerant cluster less wireless sensor networks"
    - "divide and rule scheme for energy efficient routing in wireless sensor networks"
    - "maximizing the lifetime of multi chain pegasis using sink mobility"
    - "on adaptive energy efficient transmission in wsns"
    - "identifying design requirements for wireless routing link metrics"
    - "interference and bandwidth adjusted etx in wireless multi hop networks"

Connected through hyperedge HE-5 (induced by source paper "am discnt angular multi hop distance based circular network transmission protocol for wsns"):
  with members:
    - "hybrid deec towards efficient energy utilization in wireless sensor networks"
    - "improving network efficiency by removing energy holes in wsns"
    - "maximizing the lifetime of multi chain pegasis using sink mobility"
    - "identifying design requirements for wireless routing link metrics"
    - "performance study of etx based wireless routing metrics"

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)