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: "oncilla robot a versatile open source quadruped research robot with compliant pantograph legs"
  Abstract: We present Oncilla robot, a novel mobile, quadruped legged locomotion machine. This large-cat sized, 5.1kg robot is one of a kind of a recent, bioinspired legged robot class designed with the capability of model-free locomotion control. Animal legged locomotion in rough terrain is clearly shaped by sensor feedback systems. Results with Oncilla robot show that agile and versatile locomotion is possible without sensory signals to some extend, and tracking becomes robust when feedback control is added (Ajallooeian 2015). By incorporating mechanical and control blueprints inspired from animals, and by observing the resulting robot locomotion characteristics, we aim to understand the contribution of individual components. Legged robots have a wide mechanical and control design parameter space, and a unique potential as research tools to investigate principles of biomechanics and legged locomotion control. But the hardware and controller design can be a steep initial hurdle for academic research. To facilitate the easy start and development of legged robots, Oncilla-robot's blueprints are available through open-source. The robot's locomotion capabilities are shown in several scenarios. Specifically, its spring-loaded pantographic leg design compensates for overdetermined body and leg postures, i.e. during turning maneuvers, locomotion outdoors, or while going up and down slopes. The robot's active degree of freedom allow tight and swift direction changes, and turns on the spot. Presented hardware experiments are conducted in an open-loop manner, with little control and computational effort. For more versatile locomotion control, Oncilla-robot can sense leg joint rotations, and leg-trunk forces. Additional sensors can be included for feedback control with an open communication protocol interface. The robot's customized actuators are designed for robust actuation, and efficient locomotion. It trots with a cost of transport of 3.2J/Nm, at a speed of 0.63m/s (Froude number 0.25). The robot trots inclined slopes up to 10deg, at 0.25m/s. The multi-body Webots model of Oncilla robot, and Oncilla robot's extensive software architecture enables users to design and test scenarios in simulation. Controllers can directly be transferred to the real robot. Oncilla robot's blueprints are open-source published (hardware GLP v3, software LGPL v3).

Connected through hyperedge HE-1 (induced by source paper "learning active spine behaviors for dynamic and efficient locomotion in quadruped robots"):
  with members:
    - "iterative reinforcement learning based design of dynamic locomotion skills for cassie"
    - "design development and experimental realization of a quadrupedal research platform stoch"
    - "sim to real learning agile locomotion for quadruped robots"
    - "soft actor critic algorithms and applications"
    - "realizing learned quadruped locomotion behaviors through kinematic motion primitives"
    - "proximal policy optimization algorithms"
    - "tensorflow agents efficient batched reinforcement learning in tensorflow"
    - "adam a method for stochastic optimization"

Connected through hyperedge HE-2 (induced by source paper "an open torque controlled modular robot architecture for legged locomotion research"):
  with members:
    - "stanford doggo an open source quasi direct drive quadruped"
    - "quasi direct drive for low cost compliant robotic manipulation"
    - "learning a structured neural network policy for a hopping task"
    - "sim to real learning agile locomotion for quadruped robots"
    - "cable driven actuation for highly dynamic robotic systems"
    - "momentum control with hierarchical inverse dynamics on a torque controlled humanoid"
    - "structured contact force optimization for kino dynamic motion generation"

Connected through hyperedge HE-3 (induced by source paper "design development and experimental realization of a quadrupedal research platform stoch"):
  with members:
    - "realizing learned quadruped locomotion behaviors through kinematic motion primitives"

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)