human: Given a node-centered hypergraph: <hypergraph>, where nodes represent authors and hyperedges represent groups of authors who co-authored the same paper.

Details of the hypergraph:
Center node: "Mitigating application-level denial of service attacks on Web servers: A client-transparent approach"
  Abstract: Recently, we have seen increasing numbers of denial of service (DoS) attacks against online services and Web applications either for extortion reasons or for impairing and even disabling the competition. These DoS attacks have increasingly targeted the application level. Application-level DoS attacks emulate the same request syntax and network-level traffic characteristics as those of legitimate clients, thereby making the attacks much harder to detect and counter. Moreover, such attacks often target bottleneck resources such as disk bandwidth, database bandwidth, and CPU resources. In this article, we propose handling DoS attacks by using a twofold mechanism. First, we perform admission control to limit the number of concurrent clients served by the online service. Admission control is based on port hiding that renders the online service invisible to unauthorized clients by hiding the port number on which the service accepts incoming requests. Second, we perform congestion control on admitted clients to allocate more resources to good clients. Congestion control is achieved by adaptively setting a client's priority level in response to the client's requests in a way that can incorporate application-level semantics. We present a detailed evaluation of the proposed solution using two sample applications: Apache HTTPD and the TPCW benchmark (running on Apache Tomcat and IBM DB2). Our experiments show that the proposed solution incurs low performance overhead and is resilient to DoS attacks.

Connected through hyperedge HE-1 (induced by source paper "Detection of HTTP flooding attacks in multiple scenarios"):
  with members:
    - "Botnet-based Distributed Denial of Service (DDoS) Attacks on Web Servers: Classification and Art"

Connected through hyperedge HE-2 (induced by source paper "A DoS-limiting network architecture"):
  with members:
    - "SANE: a protection architecture for enterprise networks"
    - "Controlling high bandwidth aggregates in the network"
    - "Cloud control with distributed rate limiting"

Question: Please tell me which research area the center author belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Computer science