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: "exploring social ties for enhanced device to device communications in wireless networks"
  Abstract: Device-to-device (D2D) communications is seen as a major technology to overcome the imminent wireless capacity crunch and to enable novel application services. In this paper, we propose a novel, social-aware approach for optimizing D2D communications by exploiting two network layers: the social network and the physical, wireless network. First we formulate the physical layer D2D network according to users' encounter histories. Subsequently, we propose a novel approach, based on the so-called Indian Buffet Process, so as to model the distribution of contents in users' online social networks. Given the online and offline social relations collected by the Evolved Node B, we jointly optimize the traffic offload process in D2D communication. Simulation results show that the proposed approach offload the traffic of Evolved Node B successfully.

Connected through hyperedge HE-1 (induced by source paper "cache enabled device to device communications offloading gain and energy cost"):
  with members:
    - "optimal caching and scheduling for cache enabled d2d communications"
    - "wireless device to device caching networks basic principles and system performance"
    - "cache enabled heterogeneous cellular networks comparison and tradeoffs"
    - "energy efficiency of downlink networks with caching at base stations"
    - "energy costs for traffic offloading by cache enabled d2d communications"
    - "a survey on device to device communication in cellular networks"
    - "living on the edge the role of proactive caching in 5g wireless networks"
    - "base station assisted device to device communications for high throughput wireless video networks"

Connected through hyperedge HE-2 (induced by source paper "high throughput opportunistic cooperative device to device communications with caching"):
  with members:
    - "wireless device to device caching networks basic principles and system performance"
    - "energy efficiency of downlink networks with caching at base stations"
    - "optimal caching placement for d2d assisted wireless caching networks"
    - "optimal geographic caching in cellular networks"
    - "a survey on device to device communication in cellular networks"
    - "living on the edge the role of proactive caching in 5g wireless networks"
    - "mixed timescale precoding and cache control in cached mimo interference network"
    - "base station assisted device to device communications for high throughput wireless video networks"

Connected through hyperedge HE-3 (induced by source paper "offloading in software defined network at edge with information asymmetry a contract theoretical approach"):
  with members:
    - "contract based cooperative spectrum sharing"

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)