human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge groups authors who co-authored the same paper.

Details of the hypergraph:
Center hyperedge (induced by source paper "Analyses of Crypto Module for Gbps VPN System"):
  Abstract: A VPN is widely used in a communications environment which access is controlled to permit peer connections only within a defined community of interest. It is constructed through some form of partitioning of a common underlying communication medium, where this underlying communications medium provides services to the network on a non-exclusive basis. In this paper, we have analyzed a variety of architecture to implement Giga bps VPN system. The proposed architecture will satisfy the needs of clients who adopt Giga bps VPN system in the various environments.

Includes members:
  Member "Parts-Based Feature Extraction of Spectrum of Speech Signal Using Non-Negative Matrix Factorization":
    also connected through other hyperedges:
      (none)

Question: Please tell me which research area the co-authored paper (i.e., the source paper of the center hyperedge) belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Computer science