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: "vm mad a cloud cluster software for service oriented academic environments"
  Abstract: The availability of powerful computing hardware in IaaS clouds makes cloud computing attractive also for computational workloads that were up to now almost exclusively run on HPC clusters.

Connected through hyperedge HE-1 (induced by source paper "cloud brokerage a systematic survey"):
  with members:
    - "price and performance of cloud hosted virtual network functions analysis and future challenges"
    - "same same but different a descriptive differentiation of intra cloud iaas services"
    - "daleel simplifying cloud instance selection using machine learning"
    - "socloud a service oriented component based paas for managing portability provisioning elasticity and high availability across multiple clouds"
    - "container based cloud virtual machine benchmarking"
    - "cloud services brokerage a survey and research roadmap"
    - "academic cloud computing research five pitfalls and five opportunities"
    - "experiences of using a hybrid cloud to construct an environmental virtual observatory"

Connected through hyperedge HE-2 (induced by source paper "towards a swiss national research infrastructure"):
  with members:
    - "batch oriented software appliances"
    - "gridcertlib a single sign on solution for grid web applications and portals"

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.DC(Distributed, Parallel, and Cluster Computing)