pir
Dynamic Buffers: Cost-Efficient Planning for Tabletop Rearrangement with Stacking
Barghi, Arman, Hosseini, Hamed, Ghasemi, Seraj, Masouleh, Mehdi Tale, Kalhor, Ahmad
Abstract--Rearranging objects in cluttered tabletop environments remains a long-standing challenge in robotics. Classical planners often generate inefficient, high-cost plans by shuffling objects individually and using fixed buffers--temporary spaces such as empty table regions or static stacks--to resolve conflicts. When only free table locations are used as buffers, dense scenes become inefficient, since placing an object can restrict others from reaching their goals and complicate planning. Allowing stacking provides extra buffer capacity, but conventional stacking is static: once an object supports another, the base cannot be moved, which limits efficiency. T o overcome these issues, a novel planning primitive called the Dynamic Buffer is introduced. Inspired by human grouping strategies, it enables robots to form temporary, movable stacks that can be transported as a unit. This improves both feasibility and efficiency in dense layouts, and it also reduces travel in large-scale settings where space is abundant. Compared with a state-of-the-art rearrangement planner, the approach reduces manipulator travel cost by 11.89% in dense scenarios with a stationary robot and by 5.69% in large, low-density settings with a mobile manipulator . Practicality is validated through experiments on a Delta parallel robot with a two-finger gripper . These findings establish dynamic buffering as a key primitive for cost-efficient and robust rearrangement planning. The growing field of Embodied AI is focused on creating autonomous systems that can physically interact with and modify their environments to achieve goals. A crucial aspect of this interaction is the ability to rearrange objects, a task identified as a canonical challenge for embodied agents [1].
Physics-Informed Regression: Parameter Estimation in Parameter-Linear Nonlinear Dynamic Models
Nielsen, Jonas Søeborg, Jacobsen, Marcus Galea, Olson, Albert Brincker, Sørensen, Mads Peter, Engsig-Karup, Allan Peter
We present a new efficient hybrid parameter estimation method based on the idea, that if nonlinear dynamic models are stated in terms of a system of equations that is linear in terms of the parameters, then regularized ordinary least squares can be used to estimate these parameters from time series data. We introduce the term "Physics-Informed Regression" (PIR) to describe the proposed data-driven hybrid technique as a way to bridge theory and data by use of ordinary least squares to efficiently perform parameter estimation of the model coefficients of different parameter-linear models; providing examples of models based on nonlinear ordinary equations (ODE) and partial differential equations (PDE). The focus is on parameter estimation on a selection of ODE and PDE models, each illustrating performance in different model characteristics. For two relevant epidemic models of different complexity and number of parameters, PIR is tested and compared against the related technique, physics-informed neural networks (PINN), both on synthetic data generated from known target parameters and on real public Danish time series data collected during the COVID-19 pandemic in Denmark. Both methods were able to estimate the target parameters, while PIR showed to perform noticeably better, especially on a compartment model with higher complexity. Given the difference in computational speed, it is concluded that the PIR method is superior to PINN for the models considered. It is also demonstrated how PIR can be applied to estimate the time-varying parameters of a compartment model that is fitted using real Danish data from the COVID-19 pandemic obtained during a period from 2020 to 2021. The study shows how data-driven and physics-informed techniques may support reliable and fast -- possibly real-time -- parameter estimation in parameter-linear nonlinear dynamic models.
- North America > United States (0.14)
- Europe > Denmark > Capital Region > Kongens Lyngby (0.14)
- Europe > Denmark > Capital Region > Copenhagen (0.04)
- Health & Medicine > Therapeutic Area > Infections and Infectious Diseases (1.00)
- Health & Medicine > Therapeutic Area > Immunology (1.00)
- Health & Medicine > Epidemiology (1.00)
Segmentation of Muscularis Propria in Colon Histopathology Images Using Vision Transformers for Hirschsprung's Disease
Megahed, Youssef, Fuller, Anthony, Abou-Alwan, Saleh, Demellawy, Dina El, Chan, Adrian D. C.
Hirschsprung's disease (HD) is a congenital birth defect diagnosed by identifying the lack of ganglion cells within the colon's muscularis propria, specifically within the myenteric plexus regions. There may be advantages for quantitative assessments of histopathology images of the colon, such as counting the ganglion and assessing their spatial distribution; however, this would be time-intensive for pathologists, costly, and subject to inter- and intra-rater variability. Previous research has demonstrated the potential for deep learning approaches to automate histopathology image analysis, including segmentation of the muscularis propria using convolutional neural networks (CNNs). Recently, Vision Transformers (ViTs) have emerged as a powerful deep learning approach due to their self-attention. This study explores the application of ViTs for muscularis propria segmentation in calretinin-stained histopathology images and compares their performance to CNNs and shallow learning methods. The ViT model achieved a DICE score of 89.9% and Plexus Inclusion Rate (PIR) of 100%, surpassing the CNN (DICE score of 89.2%; PIR of 96.0%) and k-means clustering method (DICE score of 80.7%; PIR 77.4%). Results assert that ViTs are a promising tool for advancing HD-related image analysis.
Multimodal Policies with Physics-informed Representations
Feng, Haodong, Hu, Peiyan, Wang, Yue, Fan, Dixia
In the control problems of the PDE systems, observation is important to make the decision. However, the observation is generally sparse and missing in practice due to the limitation and fault of sensors. The above challenges cause observations with uncertain quantities and modalities. Therefore, how to leverage the uncertain observations as the states in control problems of the PDE systems has become a scientific problem. The dynamics of PDE systems rely on the initial conditions, boundary conditions, and PDE formula. Given the above three elements, PINNs can be used to solve the PDE systems. In this work, we discover that the neural network can also be used to identify and represent the PDE systems using PDE loss and sparse data loss. Inspired by the above discovery, we propose a Physics-Informed Representation (PIR) algorithm for multimodal policies in PDE systems' control. It leverages PDE loss to fit the neural network and data loss calculated on the observations with random quantities and modalities to propagate the information of initial conditions and boundary conditions into the inputs. The inputs can be the learnable parameters or the output of the encoders. Then, under the environments of the PDE systems, such inputs are the representation of the current state. In our experiments, the PIR illustrates the superior consistency with the features of the ground truth compared with baselines, even when there are missing modalities. Furthermore, PIR has been successfully applied in the downstream control tasks where the robot leverages the learned state by PIR faster and more accurately, passing through the complex vortex street from a random starting location to reach a random target.
Unveiling In-Context Learning: A Coordinate System to Understand Its Working Mechanism
Zhao, Anhao, Ye, Fanghua, Fu, Jinlan, Shen, Xiaoyu
Large language models (LLMs) exhibit remarkable in-context learning (ICL) capabilities. However, the underlying working mechanism of ICL remains poorly understood. Recent research presents two conflicting views on ICL: One attributes it to LLMs' inherent ability of task recognition, deeming label correctness and shot numbers of demonstrations as not crucial; the other emphasizes the impact of similar examples in the demonstrations, stressing the need for label correctness and more shots. In this work, we provide a Two-Dimensional Coordinate System that unifies both views into a systematic framework. The framework explains the behavior of ICL through two orthogonal variables: whether LLMs can recognize the task and whether similar examples are presented in the demonstrations. We propose the peak inverse rank metric to detect the task recognition ability of LLMs and study LLMs' reactions to different definitions of similarity. Based on these, we conduct extensive experiments to elucidate how ICL functions across each quadrant on multiple representative classification tasks. Finally, we extend our analyses to generation tasks, showing that our coordinate system can also be used to interpret ICL for generation tasks effectively.
- North America > United States > Washington > King County > Seattle (0.14)
- Europe > France (0.04)
- Europe > Germany (0.04)
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Pre-insertion resistors temperature prediction based on improved WOA-SVR
Dai, Honghe, Mo, Site, Wang, Haoxin, Yin, Nan, Fan, Songhai, Li, Bixiong
The pre-insertion resistors (PIR) within high-voltage circuit breakers are critical components and warm up by generating Joule heat when an electric current flows through them. Elevated temperature can lead to temporary closure failure and, in severe cases, the rupture of PIR. To accurately predict the temperature of PIR, this study combines finite element simulation techniques with Support Vector Regression (SVR) optimized by an Improved Whale Optimization Algorithm (IWOA) approach. The IWOA includes Tent mapping, a convergence factor based on the sigmoid function, and the Ornstein-Uhlenbeck variation strategy. The IWOA-SVR model is compared with the SSA-SVR and WOA-SVR. The results reveal that the prediction accuracies of the IWOA-SVR model were 90.2% and 81.5% (above 100$^\circ$C) in the 3$^\circ$C temperature deviation range and 96.3% and 93.4% (above 100$^\circ$C) in the 4$^\circ$C temperature deviation range, surpassing the performance of the comparative models. This research demonstrates the method proposed can realize the online monitoring of the temperature of the PIR, which can effectively prevent thermal faults PIR and provide a basis for the opening and closing of the circuit breaker within a short period.
- Asia > China > Sichuan Province > Chengdu (0.05)
- Asia > China > Liaoning Province > Shenyang (0.04)
Protect Your Score: Contact Tracing With Differential Privacy Guarantees
Romijnders, Rob, Louizos, Christos, Asano, Yuki M., Welling, Max
The pandemic in 2020 and 2021 had enormous economic and societal consequences, and studies show that contact tracing algorithms can be key in the early containment of the virus. While large strides have been made towards more effective contact tracing algorithms, we argue that privacy concerns currently hold deployment back. The essence of a contact tracing algorithm constitutes the communication of a risk score. Yet, it is precisely the communication and release of this score to a user that an adversary can leverage to gauge the private health status of an individual. We pinpoint a realistic attack scenario and propose a contact tracing algorithm with differential privacy guarantees against this attack. The algorithm is tested on the two most widely used agent-based COVID19 simulators and demonstrates superior performance in a wide range of settings. Especially for realistic test scenarios and while releasing each risk score with epsilon=1 differential privacy, we achieve a two to ten-fold reduction in the infection rate of the virus. To the best of our knowledge, this presents the first contact tracing algorithm with differential privacy guarantees when revealing risk scores for COVID19.
- Asia > Middle East > Jordan (0.04)
- Europe > Netherlands > North Holland > Amsterdam (0.04)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- (4 more...)