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: "TOSSIM: accurate and scalable simulation of entire TinyOS applications"
  Abstract: Accurate and scalable simulation has historically been a key enabling factor for systems research. We present TOSSIM, a simulator for TinyOS wireless sensor networks. By exploiting the sensor network domain and TinyOS's design, TOSSIM can capture network behavior at a high fidelity while scaling to thousands of nodes. By using a probabilistic bit error model for the network, TOSSIM remains simple and efficient, but expressive enough to capture a wide range of network interactions. Using TOSSIM, we have discovered several bugs in TinyOS, ranging from network bit-level MAC interactions to queue overflows in an ad-hoc routing protocol. Through these and other evaluations, we show that detailed, scalable sensor network simulation is possible.

Connected through hyperedge HE-1 (induced by source paper "Fine-grained network time synchronization using reference broadcasts"):
  with members:
    - "Stitching: pen gestures that span multiple displays"
    - "Sensor networks for medical care"
    - "A wireless sensor network For structural monitoring"
    - "Locating tiny sensors in time and space: a case study"
    - "PSKA: Usable and Secure Key Agreement Scheme for Body Area Networks"
    - "RMAC: A Routing-Enhanced Duty-Cycle MAC Protocol for Wireless Sensor Networks"

Connected through hyperedge HE-2 (induced by source paper "CotsBots: an off-the-shelf platform for distributed robotics"):
  with members:
    - "Stochastic event capture using mobile sensors subject to a quality metric"

Connected through hyperedge HE-3 (induced by source paper "An analysis of unreliability and asymmetry in low-power wireless links"):
  with members:
    - "Cluster size optimization in sensor networks with decentralized cluster-based protocols"

Connected through hyperedge HE-4 (induced by source paper "Do LoRa Low-Power Wide-Area Networks Scale?"):
  with members:
    - "When LoRaWAN Frames Collide"

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