Energy
BRIDGE: Bootstrapping Text to Control Time-Series Generation via Multi-Agent Iterative Optimization and Diffusion Modelling
Li, Hao, Huang, Yu-Hao, Xu, Chang, Schlegel, Viktor, Jiang, Ren-He, Batista-Navarro, Riza, Nenadic, Goran, Bian, Jiang
For example, realistic Time-series Generation (TSG) is a prominent synthetic medical electrocardiogram (ECG) patterns research area with broad applications in simulations, can be used to train medical residents (Hong & Chun, 2023), data augmentation, and counterfactual while simulating regional electricity usage can be used to analysis. While existing methods have shown stress test the power grid (Westgaard et al., 2021). Although promise in unconditional single-domain TSG, some remarkable works (Huang & Deng, 2023; Bao et al., real-world applications demand for cross-domain 2024) have been done for TSG, showing promising results approaches capable of controlled generation tailored in generating realistic and coherent time series (TS), most to domain-specific constraints and instancelevel of them focus on the basic setting--unconditional single requirements. In this paper, we argue that domain generation. However, in real application scenarios, text can provide semantic insights, domain information there are specific constraints or requirements for the generated and instance-specific temporal patterns, TS to be met, such as specifying domain-specific characteristics, to guide and improve TSG. We introduce "Text-incorporating prior knowledge (Yuan & Qiao, Controlled TSG", a task focused on generating realistic 2024), or satisfying operational constraints (Coletta et al., time series by incorporating textual descriptions.
Is Bellman Equation Enough for Learning Control?
You, Haoxiang, Molu, Lekan, Abraham, Ian
The Bellman equation and its continuous-time counterpart, the Hamilton-Jacobi-Bellman (HJB) equation, serve as necessary conditions for optimality in reinforcement learning and optimal control. While the value function is known to be the unique solution to the Bellman equation in tabular settings, we demonstrate that this uniqueness fails to hold in continuous state spaces. Specifically, for linear dynamical systems, we prove the Bellman equation admits at least $\binom{2n}{n}$ solutions, where $n$ is the state dimension. Crucially, only one of these solutions yields both an optimal policy and a stable closed-loop system. We then demonstrate a common failure mode in value-based methods: convergence to unstable solutions due to the exponential imbalance between admissible and inadmissible solutions. Finally, we introduce a positive-definite neural architecture that guarantees convergence to the stable solution by construction to address this issue.
Conformal Prediction with Upper and Lower Bound Models
Li, Miao, Klamkin, Michael, Tanneau, Mathieu, Zandehshahvar, Reza, Van Hentenryck, Pascal
Quantifying the uncertainty of machine learning models is crucial for numerous applications, particularly in large-scale real-world scenarios where prediction sets, rather than point predictions, enable more flexible and informed decision making. Uncertainty quantification (UQ) methods are essential for characterizing the unpredictibility arising in various real-world problems across science and engineering. Initially proposed by Vovk et al. [2005], CP is a popular distribution-free method for UQ, largely due to its ability to provide finite-sample coverage guarantees and its computational efficiency. Most studies in CP focus on constructing prediction intervals based on a fitted mean model. This work introduces a novel setting where the value of interest is estimated using only a pair of valid upper and lower bounds, instead of a mean model. While valid bounds themselves provide perfect coverage by definition, they can sometimes be overly conservative. By slightly reducing the coverage level, these bounds can be tightened, resulting in significantly smaller intervals with theoretical guarantees and greater utility for decision making.
Predictive Kinematic Coordinate Control for Aerial Manipulators based on Modified Kinematics Learning
Li, Zhengzhen, Shen, Jiahao, Ji, Mengyu, Cao, Huazi, Zhao, Shiyu
High-precision manipulation has always been a developmental goal for aerial manipulators. This paper investigates the kinematic coordinate control issue in aerial manipulators. We propose a predictive kinematic coordinate control method, which includes a learning-based modified kinematic model and a model predictive control (MPC) scheme based on weight allocation. Compared to existing methods, our proposed approach offers several attractive features. First, the kinematic model incorporates closed-loop dynamics characteristics and online residual learning. Compared to methods that do not consider closed-loop dynamics and residuals, our proposed method has improved accuracy by 59.6$\%$. Second, a MPC scheme that considers weight allocation has been proposed, which can coordinate the motion strategies of quadcopters and manipulators. Compared to methods that do not consider weight allocation, the proposed method can meet the requirements of more tasks. The proposed approach is verified through complex trajectory tracking and moving target tracking experiments. The results validate the effectiveness of the proposed method.
Artificial Intelligence in Reactor Physics: Current Status and Future Prospects
Zhang, Ruizhi, Zhu, Shengfeng, Wang, Kan, She, Ding, Argaud, Jean-Philippe, Bouriquet, Bertrand, Li, Qing, Gong, Helin
Reactor physics is the study of neutron properties, focusing on using models to examine the interactions between neutrons and materials in nuclear reactors. Artificial intelligence (AI) has made significant contributions to reactor physics, e.g., in operational simulations, safety design, real-time monitoring, core management and maintenance. This paper presents a comprehensive review of AI approaches in reactor physics, especially considering the category of Machine Learning (ML), with the aim of describing the application scenarios, frontier topics, unsolved challenges and future research directions. From equation solving and state parameter prediction to nuclear industry applications, this paper provides a step-by-step overview of ML methods applied to steady-state, transient and combustion problems. Most literature works achieve industry-demanded models by enhancing the efficiency of deterministic methods or correcting uncertainty methods, which leads to successful applications. However, research on ML methods in reactor physics is somewhat fragmented, and the ability to generalize models needs to be strengthened. Progress is still possible, especially in addressing theoretical challenges and enhancing industrial applications such as building surrogate models and digital twins.
SAGE-Amine: Generative Amine Design with Multi-Property Optimization for Efficient CO2 Capture
Lim, Hocheol, Cho, Hyein, Kim, Jeonghoon
Efficient CO2 capture is vital for mitigating climate change, with amine-based solvents being widely used due to their strong reactivity with CO2. However, optimizing key properties such as basicity, viscosity, and absorption capacity remains challenging, as traditional methods rely on labor-intensive experimentation and predefined chemical databases, limiting the exploration of novel solutions. Here, SAGE-Amine was introduced, a generative modeling approach that integrates Scoring-Assisted Generative Exploration (SAGE) with quantitative structure-property relationship models to design new amines tailored for CO2 capture. Unlike conventional virtual screening restricted to existing compounds, SAGE-Amine generates novel amines by leveraging autoregressive natural language processing models trained on amine datasets. SAGE-Amine identified known amines for CO2 capture from scratch and successfully performed single-property optimization, increasing basicity or reducing viscosity or vapor pressure. Furthermore, it facilitated multi-property optimization, simultaneously achieving high basicity with low viscosity and vapor pressure. The 10 top-ranked amines were suggested using SAGE-Amine and their thermodynamic properties were further assessed using COSMO-RS simulations, confirming their potential for CO2 capture. These results highlight the potential of generative modeling in accelerating the discovery of amine solvents and expanding the possibilities for industrial CO2 capture applications.
Weakly-Constrained 4D Var for Downscaling with Uncertainty using Data-Driven Surrogate Models
Dinenis, Philip, Rao, Vishwas, Anitescu, Mihai
Dynamic downscaling typically involves using numerical weather prediction (NWP) solvers to refine coarse data to higher spatial resolutions. Data-driven models such as FourCastNet have emerged as a promising alternative to the traditional NWP models for forecasting. Once these models are trained, they are capable of delivering forecasts in a few seconds, thousands of times faster compared to classical NWP models. However, as the lead times, and, therefore, their forecast window, increase, these models show instability in that they tend to diverge from reality. In this paper, we propose to use data assimilation approaches to stabilize them when used for downscaling tasks. Data assimilation uses information from three different sources, namely an imperfect computational model based on partial differential equations (PDE), from noisy observations, and from an uncertainty-reflecting prior. In this work, when carrying out dynamic downscaling, we replace the computationally expensive PDE-based NWP models with FourCastNet in a ``weak-constrained 4DVar framework" that accounts for the implied model errors. We demonstrate the efficacy of this approach for a hurricane-tracking problem; moreover, the 4DVar framework naturally allows the expression and quantification of uncertainty. We demonstrate, using ERA5 data, that our approach performs better than the ensemble Kalman filter (EnKF) and the unstabilized FourCastNet model, both in terms of forecast accuracy and forecast uncertainty.
Improving Oil Slick Trajectory Simulations with Bayesian Optimization
Accarino, Gabriele, De Carlo, Marco M., Atake, Igor, Elia, Donatello, Dissanayake, Anusha L., Neves, Antonio Augusto Sepp, Ibaรฑez, Juan Peรฑa, Epicoco, Italo, Nassisi, Paola, Fiore, Sandro, Coppini, Giovanni
Accurate simulations of oil spill trajectories are essential for supporting practitioners' response and mitigating environmental and socioeconomic impacts. Numerical models, such as MEDSLIK-II, simulate advection, dispersion, and transformation processes of oil particles. However, simulations heavily rely on accurate parameter tuning, still based on expert knowledge and manual calibration. To overcome these limitations, we integrate the MEDSLIK-II numerical oil spill model with a Bayesian optimization framework to iteratively estimate the best physical parameter configuration that yields simulation closer to satellite observations of the slick. We focus on key parameters, such as horizontal diffusivity and drift factor, maximizing the Fraction Skill Score (FSS) as a measure of spatio-temporal overlap between simulated and observed oil distributions. We validate the framework for the Baniyas oil incident that occurred in Syria between August 23 and September 4, 2021, which released over 12,000 $m^3$ of oil. We show that, on average, the proposed approach systematically improves the FSS from 5.82% to 11.07% compared to control simulations initialized with default parameters. The optimization results in consistent improvement across multiple time steps, particularly during periods of increased drift variability, demonstrating the robustness of our method in dynamic environmental conditions.
SeqFusion: Sequential Fusion of Pre-Trained Models for Zero-Shot Time-Series Forecasting
Huang, Ting-Ji, Chen, Xu-Yang, Ye, Han-Jia
Unlike traditional time-series forecasting methods that require extensive in-task data for training, zero-shot forecasting can directly predict future values given a target time series without additional training data. Current zero-shot approaches primarily rely on pre-trained generalized models, with their performance often depending on the variety and relevance of the pre-training data, which can raise privacy concerns. Instead of collecting diverse pre-training data, we introduce SeqFusion in this work, a novel framework that collects and fuses diverse pre-trained models (PTMs) sequentially for zero-shot forecasting. Based on the specific temporal characteristics of the target time series, SeqFusion selects the most suitable PTMs from a batch of pre-collected PTMs, performs sequential predictions, and fuses all the predictions while using minimal data to protect privacy. Each of these PTMs specializes in different temporal patterns and forecasting tasks, allowing SeqFusion to select by measuring distances in a shared representation space of the target time series with each PTM. Experiments demonstrate that SeqFusion achieves competitive accuracy in zero-shot forecasting compared to state-of-the-art methods.
SuperGPQA: Scaling LLM Evaluation across 285 Graduate Disciplines
Team, M-A-P, Du, Xinrun, Yao, Yifan, Ma, Kaijing, Wang, Bingli, Zheng, Tianyu, Zhu, Kang, Liu, Minghao, Liang, Yiming, Jin, Xiaolong, Wei, Zhenlin, Zheng, Chujie, Deng, Kaixin, Jia, Shian, Jiang, Sichao, Liao, Yiyan, Li, Rui, Li, Qinrui, Li, Sirun, Li, Yizhi, Li, Yunwen, Ma, Dehua, Ni, Yuansheng, Que, Haoran, Wang, Qiyao, Wen, Zhoufutu, Wu, Siwei, Xing, Tianshun, Xu, Ming, Yang, Zhenzhu, Wang, Zekun Moore, Zhou, Junting, Bai, Yuelin, Bu, Xingyuan, Cai, Chenglin, Chen, Liang, Chen, Yifan, Cheng, Chengtuo, Cheng, Tianhao, Ding, Keyi, Huang, Siming, Huang, Yun, Li, Yaoru, Li, Yizhe, Li, Zhaoqun, Liang, Tianhao, Lin, Chengdong, Lin, Hongquan, Ma, Yinghao, Pang, Tianyang, Peng, Zhongyuan, Peng, Zifan, Qi, Qige, Qiu, Shi, Qu, Xingwei, Quan, Shanghaoran, Tan, Yizhou, Wang, Zili, Wang, Chenqing, Wang, Hao, Wang, Yiya, Wang, Yubo, Xu, Jiajun, Yang, Kexin, Yuan, Ruibin, Yue, Yuanhao, Zhan, Tianyang, Zhang, Chun, Zhang, Jinyang, Zhang, Xiyue, Zhang, Xingjian, Zhang, Yue, Zhao, Yongchi, Zheng, Xiangyu, Zhong, Chenghua, Gao, Yang, Li, Zhoujun, Liu, Dayiheng, Liu, Qian, Liu, Tianyu, Ni, Shiwen, Peng, Junran, Qin, Yujia, Su, Wenbo, Wang, Guoyin, Wang, Shi, Yang, Jian, Yang, Min, Cao, Meng, Yue, Xiang, Zhang, Zhaoxiang, Zhou, Wangchunshu, Liu, Jiaheng, Lin, Qunshu, Huang, Wenhao, Zhang, Ge
Large language models (LLMs) have demonstrated remarkable proficiency in mainstream academic disciplines such as mathematics, physics, and computer science. However, human knowledge encompasses over 200 specialized disciplines, far exceeding the scope of existing benchmarks. The capabilities of LLMs in many of these specialized fields-particularly in light industry, agriculture, and service-oriented disciplines-remain inadequately evaluated. To address this gap, we present SuperGPQA, a comprehensive benchmark that evaluates graduate-level knowledge and reasoning capabilities across 285 disciplines. Our benchmark employs a novel Human-LLM collaborative filtering mechanism to eliminate trivial or ambiguous questions through iterative refinement based on both LLM responses and expert feedback. Our experimental results reveal significant room for improvement in the performance of current state-of-the-art LLMs across diverse knowledge domains (e.g., the reasoning-focused model DeepSeek-R1 achieved the highest accuracy of 61.82% on SuperGPQA), highlighting the considerable gap between current model capabilities and artificial general intelligence. Additionally, we present comprehensive insights from our management of a large-scale annotation process, involving over 80 expert annotators and an interactive Human-LLM collaborative system, offering valuable methodological guidance for future research initiatives of comparable scope.