human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "bounded collision force by the sobolev norm compliance and control for interactive robots"
  Abstract: A robot making contact with a human or environment, both intended and unintended, is a major design consideration for interactive robots. Substantial experimental work has investigated the role of inertia, relative velocity, and interface stiffness in collision, but no analytical expression for maximum impact force of complex models is established. Here, the Sobolev norm is used to rigorously bound maximum impact force when both the force and its derivative are in $\mathcal{L}_p$, a condition which holds for a pure stiffness coupling damped inertias under impulsive excitation. The Sobolev norm allows unified consideration of contact with humans (free space and clamped) and pure stiffness environments, accommodating complex models without using elastic/inelastic collision assumptions. The Sobolev norm can be found through the $\mathcal{H}_2$ norm of a related system, allowing efficient computation and connection with existing control theory. The Sobolev norm is validated, first experimentally with an admittance-controlled robot, then in simulation with a linear flexible-joint robot. It is then used to investigate the impact of motor dynamics, control, joint and interface compliance on collision, and a trade-off between collision performance and environmental estimation is shown.

Connected through hyperedge HE-1 (induced by source paper "safe rendering of high impedance on a series elastic actuator with disturbance observer based torque control"):
  with members:
    - "necessary and sufficient conditions for passivity of velocity sourced impedance control of series elastic actuators"
    - "robot impedance control and passivity analysis with inner torque and velocity feedback loops"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.RO(Robotics)