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: "a service oriented infrastructure approach for mutual assistance communities"
  Abstract: Elder people are becoming a predominant aspect of our societies. As such, solutions both efficacious and cost-effective need to be sought. This paper proposes a service-oriented infrastructure approach to this problem. We propose an open and integrated service infrastructure to orchestrate the available resources (smart devices, professional carers, informal carers) to help elder or disabled people. Main characteristic of our design is the explicitly support of dynamically available service providers such as informal carers. By modeling the service description as Semantic Web Services, the service request can automatically be discovered, reasoned about and mapped onto the pool of heterogeneous service providers. We expect our approach to be able to efficiently utilize the available service resources, enrich the service options, and best match the requirements of the requesters.

Connected through hyperedge HE-1 (induced by source paper "promises and challenges of ambient assisted living systems"):
  with members:
    - "a design tool to reason about ambient assisted living systems"
    - "participant a new concept for optimally assisting the elder people"

Connected through hyperedge HE-2 (induced by source paper "service oriented communities visions and contributions towards social organizations"):
  with members:
    - "a design tool to reason about ambient assisted living systems"
    - "on the requirements of new software development"
    - "promises and challenges of ambient assisted living systems"
    - "the missing ones key ingredients towards effective ambient assisted living systems"
    - "participant a new concept for optimally assisting the elder people"

Connected through hyperedge HE-3 (induced by source paper "the missing ones key ingredients towards effective ambient assisted living systems"):
  with members:
    - "a design tool to reason about ambient assisted living systems"
    - "promises and challenges of ambient assisted living systems"
    - "participant a new concept for optimally assisting the elder people"

Connected through hyperedge HE-4 (induced by source paper "participant a new concept for optimally assisting the elder people"):
  with members:
    - "a design tool to reason about ambient assisted living systems"

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.CY(Computers and Society)