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: "design of a scalable hybrid mac protocol for heterogeneous m2m networks"
  Abstract: A robust and resilient Medium Access Control (MAC) protocol is crucial for numerous machine-type devices to concurrently access the channel in a Machine-to-Machine (M2M) network. Simplex (reservation or contention based) MAC protocols are studied in most literatures which may not be able to provide a scalable solution for M2M networks with large number of heterogeneous devices. In this paper, a scalable hybrid MAC protocol, which consists of a contention period and a transmission period, is designed for heterogeneous M2M networks. In this protocol, different devices with pre-set priorities (hierarchical contending probabilities) firstly contend the transmission opportunities following the convention based $p$-persistent CSMA mechanism. Only the successful devices will be assigned a time slot for transmission following the reservation based TDMA mechanism. If the devices failed in contention at previous frame, to ensure the fairness among all devices, their contending priorities will be raised by increasing their contending probabilities at the next frame. To balance the tradeoff between the contention and transmission period in each frame, an optimization problem is formulated to maximize the channel utility by finding the key design parameters: the contention duration, initial contending probability and the incremental indicator. Analytical and simulation results demonstrate the effectiveness of the proposed Hybrid MAC protocol.

Connected through hyperedge HE-1 (induced by source paper "network lifetime maximization for cellular based m2m networks"):
  with members:
    - "energy efficient scheduling and grouping for machine type communications over cellular networks"
    - "e 2 mac energy efficient medium access for massive m2m communications"
    - "power efficient system design for cellular based machine to machine communications"
    - "a quantitative measure of fairness and discrimination for resource allocation in shared computer systems"

Connected through hyperedge HE-2 (induced by source paper "exploiting qos flexibility for smart grid and iot applications using tv white spaces extended version"):
  with members:
    - "guaranteeing qos using unlicensed tv white spaces for smart grid applications"

Connected through hyperedge HE-3 (induced by source paper "fair scheduling for data collection in mobile sensor networks with energy harvesting"):
  with members:
    - "delay tolerant networking for long term animal tracking"
    - "autonomous surveillance for biosecurity"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "throughput maximization in wireless powered communication networks"
    - "delay based back pressure scheduling in multihop wireless networks"
    - "enabling wireless power transfer in cellular networks architecture modeling and deployment"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

Connected through hyperedge HE-4 (induced by source paper "smart grid testbed for demand focused energy management in end user environments"):
  with members:
    - "cost minimization of charging stations with photovoltaics an approach with ev classification"
    - "prioritizing consumers in smart grid a game theoretic approach"
    - "three party energy management with distributed energy resources in smart grid"

Connected through hyperedge HE-5 (induced by source paper "e 2 mac energy efficient medium access for massive m2m communications"):
  with members:
    - "reliable reporting for massive m2m communications with periodic resource pooling"
    - "power efficient system design for cellular based machine to machine communications"
    - "random deployment of data collectors for serving randomly located sensors"

Connected through hyperedge HE-6 (induced by source paper "on the capacity region of aloha protocol for the internet of things"):
  with members:
    - "prioritized random mac optimization via graph based analysis"
    - "frameless aloha protocol for wireless networks"

Connected through hyperedge HE-7 (induced by source paper "on the design of mac protocol and transmission scheduling for internet of things"):
  with members:
    - "internet of things iot a vision architectural elements and future directions"

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)