14 research outputs found
Extraneousness-Aware Imitation Learning
Visual imitation learning provides an effective framework to learn skills
from demonstrations. However, the quality of the provided demonstrations
usually significantly affects the ability of an agent to acquire desired
skills. Therefore, the standard visual imitation learning assumes near-optimal
demonstrations, which are expensive or sometimes prohibitive to collect.
Previous works propose to learn from noisy demonstrations; however, the noise
is usually assumed to follow a context-independent distribution such as a
uniform or gaussian distribution. In this paper, we consider another crucial
yet underexplored setting -- imitation learning with task-irrelevant yet
locally consistent segments in the demonstrations (e.g., wiping sweat while
cutting potatoes in a cooking tutorial). We argue that such noise is common in
real world data and term them "extraneous" segments. To tackle this problem, we
introduce Extraneousness-Aware Imitation Learning (EIL), a self-supervised
approach that learns visuomotor policies from third-person demonstrations with
extraneous subsequences. EIL learns action-conditioned observation embeddings
in a self-supervised manner and retrieves task-relevant observations across
visual demonstrations while excluding the extraneous ones. Experimental results
show that EIL outperforms strong baselines and achieves comparable policies to
those trained with perfect demonstration on both simulated and real-world robot
control tasks. The project page can be found at
https://sites.google.com/view/eil-website.Comment: 7 pages, 6 figure
RL-ViGen: A Reinforcement Learning Benchmark for Visual Generalization
Visual Reinforcement Learning (Visual RL), coupled with high-dimensional
observations, has consistently confronted the long-standing challenge of
generalization. Despite the focus on algorithms aimed at resolving visual
generalization problems, we argue that the devil is in the existing benchmarks
as they are restricted to isolated tasks and generalization categories,
undermining a comprehensive evaluation of agents' visual generalization
capabilities. To bridge this gap, we introduce RL-ViGen: a novel Reinforcement
Learning Benchmark for Visual Generalization, which contains diverse tasks and
a wide spectrum of generalization types, thereby facilitating the derivation of
more reliable conclusions. Furthermore, RL-ViGen incorporates the latest
generalization visual RL algorithms into a unified framework, under which the
experiment results indicate that no single existing algorithm has prevailed
universally across tasks. Our aspiration is that RL-ViGen will serve as a
catalyst in this area, and lay a foundation for the future creation of
universal visual generalization RL agents suitable for real-world scenarios.
Access to our code and implemented algorithms is provided at
https://gemcollector.github.io/RL-ViGen/
H-InDex: Visual Reinforcement Learning with Hand-Informed Representations for Dexterous Manipulation
Human hands possess remarkable dexterity and have long served as a source of
inspiration for robotic manipulation. In this work, we propose a human
andformed visual representation learning framework to
solve difficult terous manipulation tasks ()
with reinforcement learning. Our framework consists of three stages: (i)
pre-training representations with 3D human hand pose estimation, (ii) offline
adapting representations with self-supervised keypoint detection, and (iii)
reinforcement learning with exponential moving average BatchNorm. The last two
stages only modify parameters of the pre-trained representation in
total, ensuring the knowledge from pre-training is maintained to the full
extent. We empirically study 12 challenging dexterous manipulation tasks and
find that H-InDex largely surpasses strong baseline methods and the recent
visual foundation models for motor control. Code is available at
https://yanjieze.com/H-InDex .Comment: NeurIPS 2023. Code and videos: https://yanjieze.com/H-InDe
DrM: Mastering Visual Reinforcement Learning through Dormant Ratio Minimization
Visual reinforcement learning (RL) has shown promise in continuous control
tasks. Despite its progress, current algorithms are still unsatisfactory in
virtually every aspect of the performance such as sample efficiency, asymptotic
performance, and their robustness to the choice of random seeds. In this paper,
we identify a major shortcoming in existing visual RL methods that is the
agents often exhibit sustained inactivity during early training, thereby
limiting their ability to explore effectively. Expanding upon this crucial
observation, we additionally unveil a significant correlation between the
agents' inclination towards motorically inactive exploration and the absence of
neuronal activity within their policy networks. To quantify this inactivity, we
adopt dormant ratio as a metric to measure inactivity in the RL agent's
network. Empirically, we also recognize that the dormant ratio can act as a
standalone indicator of an agent's activity level, regardless of the received
reward signals. Leveraging the aforementioned insights, we introduce DrM, a
method that uses three core mechanisms to guide agents'
exploration-exploitation trade-offs by actively minimizing the dormant ratio.
Experiments demonstrate that DrM achieves significant improvements in sample
efficiency and asymptotic performance with no broken seeds (76 seeds in total)
across three continuous control benchmark environments, including DeepMind
Control Suite, MetaWorld, and Adroit. Most importantly, DrM is the first
model-free algorithm that consistently solves tasks in both the Dog and
Manipulator domains from the DeepMind Control Suite as well as three dexterous
hand manipulation tasks without demonstrations in Adroit, all based on pixel
observations
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
miR-150-5p Inhibits Hepatoma Cell Migration and Invasion by Targeting MMP14
<div><p>Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality worldwide. Despite progress in diagnostics and treatment of HCC, its prognosis remains poor because the molecular mechanisms underlying hepatocarcinogenesis are not well understood. In the study, we focused on identifying the role of miRNAs in HCC progression. miRNA microarray was used to analyze the differentially expressed miRNAs, and the results were validated by qPCR. We found that the miR-150-5p expression is down-regulated in HCC tissues compared with pair non-tumor tissues. miR-150-5p expression is also decreased in metastatic cancer tissues compared with pair primary tissues, indicating that miR-150-5p may be involved in HCC metastasis. Functionally, miR-150-5p inhibition significantly promotes hepatoma cell migration and invasion, whereas miR-150-5p overexpression suppresses cancer cell migration and invasion <i>in</i><i>vitro</i>. The matrix metalloproteinase 14 (MMP14) is identified as a new target gene of miR-150-5p. miR-150-5p markedly inhibits MMP14 expression in hepatoma cells, and miR-150-5p expression is negative correlation with MMP14 expression <i>in</i><i>vivo</i>. More important, re-expression of MMP14 in hepatoma cells partially reverses the effect of miR-150-5p in inhibiting cell invasion.</p></div
The characteristics of patients with HCC.
<p>Cell invasion assay of Huh7 cells (A) or HepG2 cells (B) after miR-150-5p overexpression or miR-150-5p plus MMP14 overexpression. Data are shown as the mean ± SD based on at least three independent experiments (C). *<i>p</i><0.05.</p><p>The characteristics of patients with HCC.</p
The characteristics of patients with HCC.
<p>Cell invasion assay of Huh7 cells (A) or HepG2 cells (B) after miR-150-5p overexpression or miR-150-5p plus MMP14 overexpression. Data are shown as the mean ± SD based on at least three independent experiments (C). *<i>p</i><0.05.</p><p>The characteristics of patients with HCC.</p