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 survey on wireless sensor network security"
  Abstract: Wireless sensor networks (WSNs) have recently attracted a lot of interest in the research community due their wide range of applications. Due to distributed nature of these networks and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. This problem is more critical if the network is deployed for some mission-critical applications such as in a tactical battlefield. Random failure of nodes is also very likely in real-life deployment scenarios. Due to resource constraints in the sensor nodes, traditional security mechanisms with large overhead of computation and communication are infeasible in WSNs. Security in sensor networks is, therefore, a particularly challenging task. This paper discusses the current state of the art in security mechanisms for WSNs. Various types of attacks are discussed and their countermeasures presented. A brief discussion on the future direction of research in WSN security is also included.

Connected through hyperedge HE-1 (induced by source paper "securing cluster heads in wireless sensor networks by a hybrid intrusion detection system based on data mining"):
  with members:
    - "novel hybrid intrusion detection system for clustered wireless sensor network"

Connected through hyperedge HE-2 (induced by source paper "a survey on detection of sinkhole attack in wireless sensor network"):
  with members:
    - "secured greedy perimeter stateless routing for wireless sensor networks"

Connected through hyperedge HE-3 (induced by source paper "homomorphic encryption theory and application"):
  with members:
    - "security in wireless sensor networks"
    - "security and privacy issues in wireless mesh networks a survey"
    - "an attack on privacy preserving data aggregation protocol for wireless sensor networks"
    - "secure and privacy preserving data aggregation protocols for wireless sensor networks"
    - "secure and privacy preserving authentication protocols for wireless mesh networks"
    - "a novel mechanism for detection of distributed denial of service attacks"
    - "a mechanism for detection of gray hole attack in mobile ad hoc networks"
    - "reputation and trust based systems for wireless self organizing networks"

Connected through hyperedge HE-4 (induced by source paper "security and privacy issues in wireless mesh networks a survey"):
  with members:
    - "secure and privacy preserving authentication protocols for wireless mesh networks"
    - "reputation and trust based systems for wireless self organizing networks"
    - "secure and privacy aware searching in peer to peer networks"
    - "an efficient and user privacy preserving routing protocol for wireless mesh networks"
    - "a distributed protocol for detection of packet dropping attack in mobile ad hoc networks"
    - "cross layer protocols for multimedia communications over wireless networks"
    - "secure routing in wireless mesh networks"
    - "a distributed trust management framework for detecting malicious packet dropping nodes in a mobile ad hoc network"

Connected through hyperedge HE-5 (induced by source paper "a survey on security and privacy protocols for cognitive wireless sensor networks"):
  with members:
    - "reputation and trust based systems for wireless self organizing networks"
    - "secure and privacy aware searching in peer to peer networks"
    - "an intrusion detection architecture for clustered wireless ad hoc networks"
    - "routing security issues in wireless sensor networks attacks and defenses"

Connected through hyperedge HE-6 (induced by source paper "security and privacy challenges in cognitive wireless sensor networks"):
  with members:
    - "secure and privacy aware searching in peer to peer networks"
    - "an efficient and user privacy preserving routing protocol for wireless mesh networks"
    - "a distributed protocol for detection of packet dropping attack in mobile ad hoc networks"
    - "routing security issues in wireless sensor networks attacks and defenses"

Connected through hyperedge HE-7 (induced by source paper "secure and privacy preserving data aggregation protocols for wireless sensor networks"):
  with members:
    - "an attack on privacy preserving data aggregation protocol for wireless sensor networks"
    - "reputation and trust based systems for wireless self organizing networks"
    - "internet of things applications and challenges in technology and standardization"
    - "a robust and secure aggregation protocol for wireless sensor networks"
    - "a trust based detection algorithm of selfish packet dropping nodes in a peer to peer wireless mesh network"
    - "a distributed trust and reputation framework for mobile ad hoc networks"
    - "medians and beyond new aggregation techniques for sensor networks"

Connected through hyperedge HE-8 (induced by source paper "secure and energy efficient data aggregation in wireless sensor networks"):
  with members:
    - "reputation and trust based systems for wireless self organizing networks"
    - "a distributed protocol for detection of packet dropping attack in mobile ad hoc networks"
    - "a robust and secure aggregation protocol for wireless sensor networks"
    - "a trust based detection algorithm of selfish packet dropping nodes in a peer to peer wireless mesh network"
    - "a distributed trust and reputation framework for mobile ad hoc networks"

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.CR(Cryptography and Security)