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: "A study of the internal and external effects of concurrency bugs"
  Abstract: Concurrent programming is increasingly important for achieving performance gains in the multi-core era, but it is also a difficult and error-prone task. Concurrency bugs are particularly difficult to avoid and diagnose, and therefore in order to improve methods for handling such bugs, we need a better understanding of their characteristics. In this paper we present a study of concurrency bugs in MySQL, a widely used database server. While previous studies of real-world concurrency bugs exist, they have centered their attention on the causes of these bugs. In this paper we provide a complementary focus on their effects, which is important for understanding how to detect or tolerate such bugs at run-time. Our study uncovered several interesting facts, such as the existence of a significant number of latent concurrency bugs, which silently corrupt data structures and are exposed to the user potentially much later. We also highlight several implications of our findings for the design of reliable concurrent systems.

Connected through hyperedge HE-1 (induced by source paper "Threader: a constraint-based verifier for multi-threaded programs"):
  with members:
    - "From Traces to Proofs: Proving Concurrent Programs Safe"

Connected through hyperedge HE-2 (induced by source paper "Practical Byzantine fault tolerance"):
  with members:
    - "Proactive recovery in a Byzantine-fault-tolerant system"
    - "Performance study of Byzantine Agreement Protocol with artificial neural network"
    - "Preserving peer replicas by rate-limited sampled voting"
    - "Civitas: Toward a Secure Voting System"

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