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: "grid market directory a web services based grid service publication directory"
  Abstract: As Grids are emerging as the next generation service-oriented computing platforms, they need to support Grid economy that helps in the management of supply and demand for resources and offers an economic incentive for Grid resource providers. To enable this Grid economy, a market-like Grid environment including an infrastructure that supports the publication of services and their discovery is needed. As part of the Gridbus project, we proposed and have developed a Grid Market Directory (GMD) that serves as a registry for high-level service publication and discovery in Virtual Organisations.

Connected through hyperedge HE-1 (induced by source paper "the efficiency challenges of resource discovery in grid environments"):
  with members:
    - "the anatomy of the grid enabling scalable virtual organizations"

Connected through hyperedge HE-2 (induced by source paper "a taxonomy of peer to peer based complex queries a grid perspective"):
  with members:
    - "sla based coordinated superscheduling scheme and performance for computational grids"
    - "a case for cooperative and incentive based coupling of distributed clusters"
    - "tycoon a distributed market based resource allocation system"
    - "monalisa a distributed monitoring service architecture"
    - "a performance study of monitoring and information services for distributed systems"

Connected through hyperedge HE-3 (induced by source paper "a grid service broker for scheduling distributed data oriented applications on global grids"):
  with members:
    - "alchemi a net based grid computing framework and its integration into global grids"
    - "the gridbus toolkit for service oriented grid and utility computing an overview and status report"
    - "replica selection in the globus data grid"
    - "the anatomy of the grid enabling scalable virtual organizations"

Connected through hyperedge HE-4 (induced by source paper "economic and on demand brain activity analysis on global grids"):
  with members:
    - "economic based distributed resource management and scheduling for grid computing"
    - "the anatomy of the grid enabling scalable virtual organizations"

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)