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: "Cluster size optimization in sensor networks with decentralized cluster-based protocols"
  Abstract: Network lifetime and energy-efficiency are viewed as the dominating considerations in designing cluster-based communication protocols for wireless sensor networks. This paper analytically provides the optimal cluster size that minimizes the total energy expenditure in such networks, where all sensors communicate data through their elected cluster heads to the base station in a decentralized fashion. LEACH, LEACH-Coverage, and DBS comprise three cluster-based protocols investigated in this paper that do not require any centralized support from a certain node. The analytical outcomes are given in the form of closed-form expressions for various widely-used network configurations. Extensive simulations on different networks are used to confirm the expectations based on the analytical results. To obtain a thorough understanding of the results, cluster number variability problem is identified and inspected from the energy consumption point of view.

Connected through hyperedge HE-1 (induced by source paper "On Effectiveness of Clustering Principles in Maximizing Wireless Sensor Network Lifespan"):
  with members:
    (none)

Connected through hyperedge HE-2 (induced by source paper "An analysis of unreliability and asymmetry in low-power wireless links"):
  with members:
    - "TOSSIM: accurate and scalable simulation of entire TinyOS applications"

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