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: "the mad hatter s cocktail party a social mobile audio space supporting multiple simultaneous conversations"
  Abstract: This paper presents a mobile audio space intended for use by gelled social groups. In face-to-face interactions in such social groups, conversational floors change frequently, e.g., two participants split off to form a new conversational floor, a participant moves from one conversational floor to another, etc. To date, audio spaces have provided little support for such dynamic regroupings of participants, either requiring that the participants explicitly specify with whom they wish to talk or simply presenting all participants as though they are in a single floor. By contrast, the audio space described here monitors participant behavior to identify conversational floors as they emerge. The system dynamically modifies the audio delivered to each participant to enhance the salience of the participants with whom they are currently conversing. We report a user study of the system, focusing on conversation analytic results.

Connected through hyperedge HE-1 (induced by source paper "where s the party in multi party analyzing the structure of small group sociable talk"):
  with members:
    - "how push to talk makes talk less pushy"

Connected through hyperedge HE-2 (induced by source paper "making space for stories ambiguity in the design of personal communication systems"):
  with members:
    - "how push to talk makes talk less pushy"

Connected through hyperedge HE-3 (induced by source paper "conversation analysis and the user experience"):
  with members:
    - "how push to talk makes talk less pushy"
    - "practical strategies for integrating a conversation analyst in an iterative design process"
    - "sotto voce exploring the interplay of conversation and mobile audio spaces"

Connected through hyperedge HE-4 (induced by source paper "user interfaces and the social negotiation of availability"):
  with members:
    - "how push to talk makes talk less pushy"

Connected through hyperedge HE-5 (induced by source paper "how push to talk makes talk less pushy"):
  with members:
    - "media affordances of a mobile push to talk communication service"

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.HC(Human-Computer Interaction)