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: "Modular software upgrades for distributed systems"
  Abstract: Upgrading the software of long-lived, highly-available distributed systems is difficult. It is not possible to upgrade all the nodes in a system at once, since some nodes may be unavailable and halting the system for an upgrade is unacceptable. Instead, upgrades must happen gradually, and there may be long periods of time when different nodes run different software versions and need to communicate using incompatible protocols. We present a methodology and infrastructure that make it possible to upgrade distributed systems automatically while limiting service disruption. We introduce new ways to reason about correctness in a multi-version system. We also describe a prototype implementation that supports automatic upgrades with modest overhead.

Connected through hyperedge HE-1 (induced by source paper "Abstractions for network update"):
  with members:
    - "Enforcing network-wide policies in the presence of dynamic middlebox actions using flowtags"

Connected through hyperedge HE-2 (induced by source paper "Mutatis mutandis: safe and predictable dynamic software updating"):
  with members:
    - "Live updating operating systems using virtualization"

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