Visualization authoring is an iterative process requiring users to adjust parameters to achieve desired aesthetics. Due to its complexity, users often create defective visualizations and struggle to fix them. Many seek help on forums (e.g., Stack Overflow), while others turn to AI, yet little is known about the strengths and limitations of these approaches, or how they can be effectively combined. We analyze Vega-Lite debugging cases from Stack Overflow, categorizing question types by askers, evaluating human responses, and assessing AI performance. Guided by these findings, we design a human-AI co-debugging system that combines LLM-generated suggestions with forum knowledge. We evaluated this system in a user study on 36 unresolved problems, comparing it with forum answers and LLM baselines. Our results show that while forum contributors provide accurate but slow solutions and LLMs offer immediate but sometimes misaligned guidance, the hybrid system resolves 86% of cases, higher than either alone.

This article presents a novel robust control scheme for nonlinear systems subject to asymmetric inequality saturation, modeling errors, and noise. The control scheme aims to achieve dynamic tracking targets while ensuring safe and low-noise operation of aero-engines. First, diffeomorphism theory is incorporated using the tangent function to establish an invertible mapping between a bounded input and an unbounded auxiliary input. In addition, the mapping can suppress noise. Second, a robust tracking control has been proposed for the reconstructed unbounded auxiliary system. The control consists of two parts: one to reduce nonlinearities, and the other to enhance tracking accuracy. Consequently, even under severe conditions, such as input saturation, the aero-engine system can guarantee uniform boundedness and uniform ultimate boundedness. Through numerical simulations and hardware-in-the-loop experiments, it is demonstrated that the diffeomorphism-based robust control enables smooth operation of the turbofan engine within safety limits, while maintaining high control quality across the complete flight envelope.