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: "on optimal geographical caching in heterogeneous cellular networks"
  Abstract: In this work we investigate optimal geographical caching in heterogeneous cellular networks where different types of base stations (BSs) have different cache capacities. Users request files from a content library according to a known probability distribution. The performance metric is the total hit probability, which is the probability that a user at an arbitrary location in the plane will find the content that it requires in one of the BSs that it is covered by. #R##N#We consider the problem of optimally placing content in all BSs jointly. As this problem is not convex, we provide a heuristic scheme by finding the optimal placement policy for one type of base station conditioned on the placement in all other types. We demonstrate that these individual optimization problems are convex and we provide an analytical solution. As an illustration, we find the optimal placement policy of the small base stations (SBSs) depending on the placement policy of the macro base stations (MBSs). We show how the hit probability evolves as the deployment density of the SBSs varies. We show that the heuristic of placing the most popular content in the MBSs is almost optimal after deploying the SBSs with optimal placement policies. Also, for the SBSs no such heuristic can be used; the optimal placement is significantly better than storing the most popular content. Finally, we show that solving the individual problems to find the optimal placement policies for different types of BSs iteratively, namely repeatedly updating the placement policies, does not improve the performance.

Connected through hyperedge HE-1 (induced by source paper "private information retrieval from a cellular network with caching at the edge"):
  with members:
    - "converse for multi server single message pir with side information"
    - "the capacity of private information retrieval from decentralized uncoded caching databases"
    - "private information retrieval from mds coded data in distributed storage systems"
    - "achieving private information retrieval capacity in distributed storage using an arbitrary linear code"
    - "fundamental limits of cache aided private information retrieval with unknown and uncoded prefetching"
    - "the capacity of private information retrieval with private side information"
    - "cache aided private information retrieval with partially known uncoded prefetching fundamental limits"
    - "private information retrieval from mds coded data with colluding servers settling a conjecture by freij hollanti et al"

Connected through hyperedge HE-2 (induced by source paper "content placement in cache enabled sub 6 ghz and millimeter wave multi antenna dense small cell networks"):
  with members:
    - "random caching based cooperative transmission in heterogeneous wireless networks"
    - "modeling and analyzing millimeter wave cellular systems"
    - "caching meets millimeter wave communications for enhanced mobility management in 5g networks"
    - "caching policy toward maximal success probability and area spectral efficiency of cache enabled hetnets"
    - "a tractable framework for performance analysis of dense multi antenna networks"
    - "a new look at physical layer security caching and wireless energy harvesting for heterogeneous ultra dense networks"
    - "antenna count for massive mimo 1 9 ghz versus 60 ghz"
    - "modeling and analysis for cache enabled networks with dynamic traffic"

Connected through hyperedge HE-3 (induced by source paper "joint and competitive caching designs in large scale multi tier wireless multicasting networks"):
  with members:
    - "ultra dense edge caching under spatio temporal demand and network dynamics"
    - "random caching based cooperative transmission in heterogeneous wireless networks"
    - "caching in wireless small cell networks a storage bandwidth tradeoff"
    - "optimal caching and user association in cache enabled heterogeneous wireless networks"
    - "a stackelberg game for incentive proactive caching mechanisms in wireless networks"
    - "cache enabled heterogeneous cellular networks comparison and tradeoffs"
    - "optimization and analysis of probabilistic caching in n tier heterogeneous networks"
    - "analysis and optimization of caching and multicasting in large scale cache enabled heterogeneous wireless networks"

Connected through hyperedge HE-4 (induced by source paper "cost effective cache deployment in mobile heterogeneous networks"):
  with members:
    - "cache size allocation in backhaul limited wireless networks"
    - "a learning based approach to caching in heterogenous small cell networks"
    - "optimal caching and user association in cache enabled heterogeneous wireless networks"
    - "on the delay of geographical caching methods in two tiered heterogeneous networks"
    - "mobility aware caching for content centric wireless networks modeling and methodology"
    - "wireless content caching for small cell and d2d networks"
    - "energy efficiency of downlink networks with caching at base stations"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"

Connected through hyperedge HE-5 (induced by source paper "cooperative edge caching in user centric clustered mobile networks"):
  with members:
    - "cost effective cache deployment in mobile heterogeneous networks"
    - "policy optimization for content push via energy harvesting small cells in heterogeneous networks"
    - "on the delay of geographical caching methods in two tiered heterogeneous networks"
    - "octopus a cooperative hierarchical caching strategy for cloud radio access networks"
    - "mobility aware caching for content centric wireless networks modeling and methodology"
    - "caching placement in stochastic wireless caching helper networks channel selection diversity via caching"
    - "cooperative caching and transmission design in cluster centric small cell networks"
    - "joint caching routing and channel assignment for collaborative small cell cellular networks"

Connected through hyperedge HE-6 (induced by source paper "fairness aware caching and radio resource allocation for the downlink of multi cell ofdma systems"):
  with members:
    - "analysis and optimization of caching and multicasting in large scale cache enabled wireless networks"

Connected through hyperedge HE-7 (induced by source paper "optimization and analysis of probabilistic caching in n tier heterogeneous networks"):
  with members:
    - "how much cache is needed to achieve linear capacity scaling in backhaul limited dense wireless networks"
    - "caching policy toward maximal success probability and area spectral efficiency of cache enabled hetnets"
    - "the three primary colors of mobile systems"
    - "caching in wireless small cell networks a storage bandwidth tradeoff"
    - "optimal caching placement for wireless femto caching network"
    - "analysis and optimization of caching and multicasting in large scale cache enabled heterogeneous wireless networks"
    - "caching placement in stochastic wireless caching helper networks channel selection diversity via caching"
    - "cooperative caching and transmission design in cluster centric small cell networks"

Connected through hyperedge HE-8 (induced by source paper "caching placement in stochastic wireless caching helper networks channel selection diversity via caching"):
  with members:
    - "fundamentals of cluster centric content placement in cache enabled device to device networks"
    - "cooperative caching and transmission design in cluster centric small cell networks"
    - "modeling and performance analysis of clustered device to device networks"
    - "optimal caching placement for d2d assisted wireless caching networks"
    - "analysis on cache enabled wireless heterogeneous networks"
    - "cooperative local caching under heterogeneous file preferences"
    - "optimal geographic caching in cellular networks"
    - "on fundamental trade offs of device to device communications in large wireless networks"

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.IT(Information Theory)