Energy
Classifying complex documents: comparing bespoke solutions to large language models
Here we search for the best automated classification approach for a set of complex legal documents. Our classification task is not trivial: our aim is to classify ca 30,000 public courthouse records from 12 states and 267 counties at two different levels using nine sub-categories. Specifically, we investigated whether a fine-tuned large language model (LLM) can achieve the accuracy of a bespoke custom-trained model, and what is the amount of fine-tuning necessary.
Transferring CLIP's Knowledge into Zero-Shot Point Cloud Semantic Segmentation
Wang, Yuanbin, Huang, Shaofei, Gao, Yulu, Wang, Zhen, Wang, Rui, Sheng, Kehua, Zhang, Bo, Liu, Si
Traditional 3D segmentation methods can only recognize a fixed range of classes that appear in the training set, which limits their application in real-world scenarios due to the lack of generalization ability. Large-scale visual-language pre-trained models, such as CLIP, have shown their generalization ability in the zero-shot 2D vision tasks, but are still unable to be applied to 3D semantic segmentation directly. In this work, we focus on zero-shot point cloud semantic segmentation and propose a simple yet effective baseline to transfer the visual-linguistic knowledge implied in CLIP to point cloud encoder at both feature and output levels. Both feature-level and output-level alignments are conducted between 2D and 3D encoders for effective knowledge transfer. Concretely, a Multi-granularity Cross-modal Feature Alignment (MCFA) module is proposed to align 2D and 3D features from global semantic and local position perspectives for feature-level alignment. For the output level, per-pixel pseudo labels of unseen classes are extracted using the pre-trained CLIP model as supervision for the 3D segmentation model to mimic the behavior of the CLIP image encoder. Extensive experiments are conducted on two popular benchmarks of point cloud segmentation. Our method outperforms significantly previous state-of-the-art methods under zero-shot setting (+29.2% mIoU on SemanticKITTI and 31.8% mIoU on nuScenes), and further achieves promising results in the annotation-free point cloud semantic segmentation setting, showing its great potential for label-efficient learning.
Integrated and Lightweight Design of Electro-hydraulic Ankle Prosthesis
Wei, Yi, Wang, Xingjian, Tian, Xinyu, Wang, Shaoping, Jia, Rujun
For lower limb amputees, an active ankle joint prosthesis can provide basic mobility functions. This study focuses on an ankle joint prosthesis system based on the principle of electric-hydraulic actuation. By analyzing the characteristics of human gait cycles and the mechanics of ankle joint movement, a lightweight and integrated ankle joint prosthesis is designed, considering the requirements for normal ankle joint kinematics and dynamics. The components of the prosthesis are optimized through simulation and iterative improvements, while ensuring tight integration within minimal space. The design and simulation verification of the integrated lightweight prosthesis components are achieved. This research addresses the contradiction between the high output capability and the constraints on volume and weight in prosthetic devices.
XLB: A Differentiable Massively Parallel Lattice Boltzmann Library in Python
Ataei, Mohammadmehdi, Salehipour, Hesam
The lattice Boltzmann method (LBM) has emerged as a prominent technique for solving fluid dynamics problems due to its algorithmic potential for computational scalability. We introduce XLB library, a Python-based differentiable LBM library based on the JAX platform. The architecture of XLB is predicated upon ensuring accessibility, extensibility, and computational performance, enabling scaling effectively across CPU, TPU, multi-GPU, and distributed multi-GPU or TPU systems. The library can be readily augmented with novel boundary conditions, collision models, or multi-physics simulation capabilities. XLB's differentiability and data structure is compatible with the extensive JAX-based machine learning ecosystem, enabling it to address physics-based machine learning, optimization, and inverse problems. XLB has been successfully scaled to handle simulations with billions of cells, achieving giga-scale lattice updates per second. XLB is released under the permissive Apache-2.0 license and is available on GitHub at https://github.com/Autodesk/XLB.
Machine Learning and Citizen Science Approaches for Monitoring the Changing Environment
This dissertation will combine new tools and methodologies to answer pressing questions regarding inundation area and hurricane events in complex, heterogeneous changing environments. In addition to remote sensing approaches, citizen science and machine learning are both emerging fields that harness advancing technology to answer environmental management and disaster response questions. Freshwater lakes supply a large amount of inland water resources to sustain local and regional developments. However, some lake systems depend upon great fluctuation in water surface area.
Integrated Path Tracking with DYC and MPC using LSTM Based Tire Force Estimator for Four-wheel Independent Steering and Driving Vehicle
Lim, Sungjin, Sadiq, Bilal, Jin, Yongsik, Lee, Sangho, Choi, Gyeungho, Nam, Kanghyun, Lim, Yongseob
Active collision avoidance system plays a crucial role in ensuring the lateral safety of autonomous vehicles, and it is primarily related to path planning and tracking control algorithms. In particular, the direct yaw-moment control (DYC) system can significantly improve the lateral stability of a vehicle in environments with sudden changes in road conditions. In order to apply the DYC algorithm, it is very important to accurately consider the properties of tire forces with complex nonlinearity for control to ensure the lateral stability of the vehicle. In this study, longitudinal and lateral tire forces for safety path tracking were simultaneously estimated using a long short-term memory (LSTM) neural network based estimator. Furthermore, to improve path tracking performance in case of sudden changes in road conditions, a system has been developed by combining 4-wheel independent steering (4WIS) model predictive control (MPC) and 4-wheel independent drive (4WID) direct yaw-moment control (DYC). The estimation performance of the extended Kalman filter (EKF), which are commonly used for tire force estimation, was compared. In addition, the estimated longitudinal and lateral tire forces of each wheel were applied to the proposed system, and system verification was performed through simulation using a vehicle dynamics simulator. Consequently, the proposed method, the integrated path tracking algorithm with DYC and MPC using the LSTM based estimator, was validated to significantly improve the vehicle stability in suddenly changing road conditions.
Translating Natural Language Queries to SQL Using the T5 Model
Wong, Albert, Pham, Lien, Lee, Young, Chan, Shek, Sadaya, Razel, Khmelevsky, Youry, Clement, Mathias, Cheng, Florence Wing Yau, Mahony, Joe, Ferri, Michael
This paper presents the development process of a natural language to SQL model using the T5 model as the basis. The models, developed in August 2022 for an online transaction processing system and a data warehouse, have a 73\% and 84\% exact match accuracy respectively. These models, in conjunction with other work completed in the research project, were implemented for several companies and used successfully on a daily basis. The approach used in the model development could be implemented in a similar fashion for other database environments and with a more powerful pre-trained language model.
Denoising diffusion-based synthetic generation of three-dimensional (3D) anisotropic microstructures from two-dimensional (2D) micrographs
For instance, multiscale computational analysis that employ the concept of the representative volume element (RVE) have been widely utilized to analyze the representative material response under specific boundary conditions [2, 7]. In particular, computational homogenization methods accompanying with finite element analysis (FEA) based on the asymptotic homogenization theory [8, 9], have been used to analyze the macroscopic properties of representative microstructures (i.e., RVEs) for various types of microstructural materials including particulate or fibrous composites [10-14], multi-phase polycrystalline metals [15, 16], metal matrix composites [17, 18], and lattice materials [19-21]. In general, these methods assume that the behavior of a heterogeneous material can be described by an RVE that is periodic throughout the material of interest. If an RVE is properly modeled for the subsequent computational homogenization analysis with periodic boundary conditions (PBC), and the macro-structure is sufficiently large, accurate solutions for the homogenized material properties (i.e., effective material properties) can be obtained. The homogenized properties of heterogenous materials can also be acquired based on the fast Fourier transform (FFT) [22, 23], which avoids the time-consuming FEA for computing the material response under macroscopic loading. Meanwhile, the recently proposed deep learning (DL) models [24-28] that link microstructure to material properties are gaining significant attention, due to their remarkably lower computational cost compared to conventional computational homogenization methods. For instance, Rao and Liu developed a three-dimensional convolutional neural network (3D-CNN) for homogenization of heterogeneous materials with random spherical inclusions [24]. Their results showed that after training the 3D-CNN using the training data pairs (i.e., microstructure RVEs and anisotropic material properties), the model could accurately estimate the anisotropic elastic material properties with a maximum prediction error of up to 0.5%.
Feasible Space Monitoring for Multiple Control Barrier Functions with application to Large Scale Indoor Navigation
Parwana, Hardik, Black, Mitchell, Hoxha, Bardh, Okamoto, Hideki, Fainekos, Georgios, Prokhorov, Danil, Panagou, Dimitra
Quadratic programs (QP) subject to multiple time-dependent control barrier function (CBF) based constraints have been used to design safety-critical controllers. However, ensuring the existence of a solution at all times to the QP subject to multiple CBF constraints is non-trivial. We quantify the feasible solution space of the QP in terms of its volume. We introduce a novel feasible space volume monitoring control barrier function that promotes compatibility of barrier functions and, hence, existence of a solution at all times. We show empirically that our approach not only enhances feasibility but also exhibits reduced sensitivity to changes in the hyperparameters such as gains of nominal controller. Finally, paired with a global planner, we evaluate our controller for navigation among humans in the AWS Hospital gazebo environment. The proposed controller is demonstrated to outperform the standard CBF-QP controller in maintaining feasibility.
An Online, Adaptive and Unsupervised Regression Framework with Drift Detection for Label Scarcity Contexts
In scenarios where obtaining real-time labels proves challenging, conventional approaches may result in sub-optimal performance. This paper presents an optimal strategy for streaming contexts with limited labeled data, introducing an adaptive technique for unsupervised regression. The proposed method leverages a sparse set of initial labels and introduces an innovative drift detection mechanism to enable dynamic model adaptations in response to evolving patterns in the data. To enhance adaptability, we integrate the ADWIN (ADaptive WINdowing) algorithm with error generalization based on Root Mean Square Error (RMSE). ADWIN facilitates real-time drift detection, while RMSE provides a robust measure of model prediction accuracy. This combination enables our multivariate method to effectively navigate the challenges of streaming data, continuously adapting to changing patterns while maintaining a high level of predictive precision. Finally, we evaluate the performance of our multivariate method across various public datasets, comparing it to non-adapting baselines. Through comprehensive assessments, we demonstrate the superior efficacy of our adaptive regression technique for tasks where obtaining labels in real-time is a significant challenge. The results underscore the method's capacity to outperform traditional approaches and highlight its potential in scenarios characterized by label scarcity and evolving data patterns.