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: "location cheating a security challenge to location based social network services"
  Abstract: Location-based mobile social network services such as foursquare and Gowalla have grown exponentially over the past several years. These location-based services utilize the geographical position to enrich user experiences in a variety of contexts, including location-based searching and location-based mobile advertising. To attract more users, the location-based mobile social network services provide real-world rewards to the user, when a user checks in at a certain venue or location. This gives incentives for users to cheat on their locations. In this report, we investigate the threat of location cheating attacks, find the root cause of the vulnerability, and outline the possible defending mechanisms. We use foursquare as an example to introduce a novel location cheating attack, which can easily pass the current location verification mechanism (e.g., cheater code of foursquare). We also crawl the foursquare website. By analyzing the crawled data, we show that automated large scale cheating is possible. Through this work, we aim to call attention to location cheating in mobile social network services and provide insights into the defending mechanisms.

Connected through hyperedge HE-1 (induced by source paper "a survey on context based co presence detection techniques"):
  with members:
    - "6thsense a context aware sensor based attack detector for smart devices"
    - "sound proof usable two factor authentication based on ambient sound"

Connected through hyperedge HE-2 (induced by source paper "privacy and security in online social networks a survey"):
  with members:
    - "social fingerprinting detection of spambot groups through dna inspired behavioral modeling"
    - "the paradigm shift of social spambots evidence theories and tools for the arms race"
    - "truetop a sybil resilient system for user influence measurement on twitter"
    - "the rise of social bots"
    - "privacy concerns vs user behavior in community question answering"
    - "special issue on foundations of social computing enabling social applications via decentralized social data management"
    - "the social world of content abusers in community question answering"
    - "online social networks threats and solutions"

Connected through hyperedge HE-3 (induced by source paper "defending against sybil devices in crowdsourced mapping services"):
  with members:
    - "exploiting social navigation"
    - "social turing tests crowdsourcing sybil detection"

Connected through hyperedge HE-4 (induced by source paper "safety challenges and solutions in mobile social networks"):
  with members:
    - "de anonymizing social networks"

Connected through hyperedge HE-5 (induced by source paper "attacks and defenses in crowdsourced mapping services"):
  with members:
    - "exploiting social navigation"

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.SI(Social and Information Networks)