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: "Joint Relay and Jammer Selection and Power Control for physical Layer Security in Two-Way Relay Networks with Imperfect CSI"
  Abstract: Physical layer security is an emerging security paradigm that can achieve secure information transmission from the source to the intended destination with the existence of malicious eavesdroppers. In this paper, joint relay/jammer selection and power control with friendly jammers for physical layer security in two-way relay networks are studied. First, several relay/jammer selection schemes are proposed to increase the secrecy capacity for source nodes and degrade the eavesdropper links simultaneously. The presented schemes select one conventional relay node and at most two friendly jammers among a number of intermediate nodes. The impact of channel estimation error on the wiretap channel is also considered. After the selection of optimal relay node and friendly jammers, a game-theoretic power control approach is introduced to deal with the interaction between the source nodes and the friendly jammers. The proposed power control approach is proven to be able to converge to the Stackelberg equilibrium, and both source nodes and friendly jammers can obtain their optimal benefits. The simulation results demonstrate the effectiveness of the relay/jammer selection schemes to enhance the secrecy capacity of the system, and validate the properties of optimization and convergence for the game-theoretic power control approach.

Connected through hyperedge HE-1 (induced by source paper "Distributed Relay Selection and Power Control for Multiuser Cooperative Communication Networks Using Buyer/Seller Game"):
  with members:
    - "Cooperative Spectrum Sharing in Cognitive Radio Networks: A Game-Theoretic Approach"
    - "Stimulating Cooperative Diversity in Wireless Ad Hoc Networks through Pricing"

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