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: "online adaptation for humanoids walking on uncertain surfaces"
  Abstract: In this paper, an online adaptation algorithm for bipedal walking on uneven surfaces with height uncertainty is proposed. In order to generate walking patterns on flat terrains, the trajectories in the task space are planned to satisfy the dynamic balance and slippage avoidance constraints, and also to guarantee smooth landing of the swing foot. To ensure smooth landing of the swing foot on surfaces with height uncertainty, the preplanned trajectories in the task space should be adapted. The proposed adaptation algorithm consists of two stages. In the first stage, once the swing foot reaches its maximum height, the supervisory control is initiated until the touch is detected. After the detection, the trajectories in the task space are modified to guarantee smooth landing. In the second stage, this modification is preserved during the Double Support Phase (DSP), and released in the next Single Support Phase (SSP). Effectiveness of the proposed online adaptation algorithm is experimentally verified through realization of the walking patterns on the SURENA III humanoid robot, designed and fabricated at CAST. The walking is tested on a surface with various flat obstacles, where the swing foot is prone to either land on the ground soon or late.

Connected through hyperedge HE-1 (induced by source paper "a robust walking controller based on online step location and duration optimization for bipedal locomotion"):
  with members:
    - "walking stabilization using step timing and location adjustment on the humanoid robot atlas"
    - "dynamic walking over rough terrains by nonlinear predictive control of the floating base inverted pendulum"
    - "when to make a step tackling the timing problem in multi contact locomotion by topp mpc"
    - "momentum control with hierarchical inverse dynamics on a torque controlled humanoid"
    - "structured contact force optimization for kino dynamic motion generation"
    - "step timing adjustment a step toward generating robust gaits"
    - "a convex model of momentum dynamics for multi contact motion generation"
    - "stepping stabilization using a combination of dcm tracking and step adjustment"

Connected through hyperedge HE-2 (induced by source paper "walking control based on step timing adaptation"):
  with members:
    - "whole body nonlinear model predictive control through contacts for quadrupeds"
    - "walking stabilization using step timing and location adjustment on the humanoid robot atlas"
    - "dynamic walking over rough terrains by nonlinear predictive control of the floating base inverted pendulum"
    - "when to make a step tackling the timing problem in multi contact locomotion by topp mpc"
    - "momentum control with hierarchical inverse dynamics on a torque controlled humanoid"
    - "structured contact force optimization for kino dynamic motion generation"
    - "step timing adjustment a step toward generating robust gaits"
    - "stepping stabilization using a combination of dcm tracking and step adjustment"

Connected through hyperedge HE-3 (induced by source paper "rigid vs compliant contact an experimental study on biped walking"):
  with members:
    - "momentum control with hierarchical inverse dynamics on a torque controlled humanoid"
    - "structured contact force optimization for kino dynamic motion generation"
    - "step timing adjustment a step toward generating robust gaits"
    - "stepping stabilization using a combination of dcm tracking and step adjustment"
    - "trajectory generation for multi contact momentum control"

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)