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 protocol test generation procedure"
  Abstract: Abstract   A procedure presented here generates test sequences for checking the conformity of an implementation to the control portion of a protocol specification, which is modeled as a deterministic finite-state machine (FSM). A test sequence generated by the procedure given here tours all state transitions and uses a unique signature for each state, called the Unique Input/Output (UIO) sequence. A UIO sequence for a state is an input/output behavior that is not exhibited by any other state. An algorithm is presented for generating a minimum-length UIO sequence, should it exist, for a given state. UIO sequences may not exist for some states.

Connected through hyperedge HE-1 (induced by source paper "Test development for communication protocols: towards automation"):
  with members:
    - "Formal methods for protocol testing: a detailed study"
    - "A Systematic Approach to Automatically Derive Test Cases from Use Cases Specified in Restricted Natural Languages"

Connected through hyperedge HE-2 (induced by source paper "Validation-based test sequence generation for networks of extended finite state machines"):
  with members:
    - "Formal methods for protocol testing: a detailed study"

Connected through hyperedge HE-3 (induced by source paper "Formal methods for protocol testing: a detailed study"):
  with members:
    - "A reduced test suite for protocol conformance testing"
    - "Test development for communication protocols: towards automation"
    - "Validation-based test sequence generation for networks of extended finite state machines"
    - "Bounded sequence testing from deterministic finite state machines"
    - "Online minimization of transition systems (extended abstract)"

Connected through hyperedge HE-4 (induced by source paper "A reduced test suite for protocol conformance testing"):
  with members:
    - "Formal methods for protocol testing: a detailed study"
    - "Toward automatic generation of novice user test scripts"

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