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: "Web data integration for e-commerce applications"
  Abstract: To make them flexible, scalable, and useable, e-commerce applications require systematic development, including data integration. Traditionally, the integration proceeds in a bottom-up way. This article discusses the problems and proposes a top-down approach to overcome some of the problems. A combined yo-yo approach aims to exploit both strategies' benefits.

Connected through hyperedge HE-1 (induced by source paper "Kopplungsstrategien für Anwendungssysteme im Krankenhaus"):
  with members:
    (none)

Connected through hyperedge HE-2 (induced by source paper "Methodology of schema integration for new database applications: a practitioner's approach"):
  with members:
    - "Federated database systems for managing distributed, heterogeneous, and autonomous databases"

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