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Supplementary Material of A Unified Conditional Framework for Diffusion-based Image Restoration Yi Zhang

Neural Information Processing Systems

We provide more visualization results in Figure 1, Figure 1, Figure 1, and Figure 1. As mentioned in the limitation section of the main text, our method can generate realistic textures in most regions. However, it may restore incorrect small characters as shown in Figure 1, which is highly ill-posed. Compared with the Uformer, it shows consistent improvements in perceptual quality. Learning to see in the dark. We compare the PSNR-oriented methods and our method.




Modeling Information Blackouts in Missing Not-At-Random Time Series Data

Sunesh, Aman, Ma, Allan, Nilol, Siddarth

arXiv.org Machine Learning

Large-scale traffic forecasting relies on fixed sensor networks that often exhibit blackouts: contiguous intervals of missing measurements caused by detector or communication failures. These outages are typically handled under a Missing At Random (MAR) assumption, even though blackout events may correlate with unobserved traffic conditions (e.g., congestion or anomalous flow), motivating a Missing Not At Random (MNAR) treatment. We propose a latent state-space framework that jointly models (i) traffic dynamics via a linear dynamical system and (ii) sensor dropout via a Bernoulli observation channel whose probability depends on the latent traffic state. Inference uses an Extended Kalman Filter with Rauch-Tung-Striebel smoothing, and parameters are learned via an approximate EM procedure with a dedicated update for detector-specific missingness parameters. On the Seattle inductive loop detector data, introducing latent dynamics yields large gains over naive baselines, reducing blackout imputation RMSE from 7.02 (LOCF) and 5.02 (linear interpolation + seasonal naive) to 4.23 (MAR LDS), corresponding to about a 64% reduction in MSE relative to LOCF. Explicit MNAR modeling provides a consistent but smaller additional improvement on real data (imputation RMSE 4.20; 0.8% RMSE reduction relative to MAR), with similar modest gains for short-horizon post-blackout forecasts (evaluated at 1, 3, and 6 steps). In controlled synthetic experiments, the MNAR advantage increases as the true missingness dependence on latent state strengthens. Overall, temporal dynamics dominate performance, while MNAR modeling offers a principled refinement that becomes most valuable when missingness is genuinely informative.


Code Repair with LLMs gives an Exploration-Exploitation Tradeoff

Neural Information Processing Systems

Iteratively improving and repairing source code with large language models (LLMs), known as refinement, has emerged as a popular way of generating programs that would be too complex to construct in one shot. Given a bank of test cases, together with a candidate program, an LLM can improve that program by being prompted with failed test cases. But it remains an open question how to best iteratively refine code, with prior work employing simple greedy or breadth-first strategies. We show here that refinement exposes an explore-exploit tradeoff: exploit by refining the program that passes the most test cases, or explore by refining a lesser considered program. We frame this as an arm-acquiring bandit problem, which we solve with Thompson Sampling. The resulting LLM-based program synthesis algorithm is broadly applicable: Across loop invariant synthesis, visual reasoning puzzles, and competition programming problems, we find that our new method can solve more problems using fewer language model calls.


Learning Motion Refinement for Unsupervised Face Animation

Neural Information Processing Systems

Unsupervised face animation aims to generate a human face video based on theappearance of a source image, mimicking the motion from a driving video. Existingmethods typically adopted a prior-based motion model (e.g., the local affine motionmodel or the local thin-plate-spline motion model). While it is able to capturethe coarse facial motion, artifacts can often be observed around the tiny motionin local areas (e.g., lips and eyes), due to the limited ability of these methodsto model the finer facial motions. In this work, we design a new unsupervisedface animation approach to learn simultaneously the coarse and finer motions. Inparticular, while exploiting the local affine motion model to learn the global coarsefacial motion, we design a novel motion refinement module to compensate forthe local affine motion model for modeling finer face motions in local areas.


LeDex: Training LLMs to Better Self-Debug and Explain Code

Neural Information Processing Systems

In the domain of code generation, self-debugging is crucial. It allows LLMs to refine their generated code based on execution feedback. This is particularly important because generating correct solutions in one attempt proves challenging for complex tasks. Prior works on self-debugging mostly focus on prompting methods by providing LLMs with few-shot examples, which work poorly on small open-sourced LLMs. In this work, we propose LeDex, a training framework that significantly improves the self-debugging capability of LLMs. Intuitively, we observe that a chain of explanations on the wrong code followed by code refinement helps LLMs better analyze the wrong code and do refinement. We thus propose an automated pipeline to collect a high-quality dataset for code explanation and refinement by generating a number of explanations and refinement trajectories from the LLM itself or a larger teacher model and filtering via execution verification. We perform supervised fine-tuning (SFT) and further reinforcement learning (RL) on both success and failure trajectories with a novel reward design considering code explanation and refinement quality.