离线增强学习(RL)旨在使用先前收集的静态数据集学习最佳策略,是RL的重要范式。由于函数近似错误在分布外动作上的功能近似错误,因此在此任务上的标准RL方法通常会表现较差。尽管已经提出了各种正规化方法来减轻此问题,但它们通常受到表达有限的策略类别的限制,有时会导致次优的解决方案。在本文中,我们提出了利用条件扩散模型作为行为克隆和策略正则化的高度表达政策类别的扩散-QL。在我们的方法中,我们学习了一个动作值函数,并在有条件扩散模型的训练损失中添加了最大化动作值的术语,这导致损失寻求接近行为政策的最佳动作。我们展示了基于扩散模型的策略的表现力以及在扩散模型下的行为克隆和策略改进的耦合都有助于扩散-QL的出色性能。我们在具有多模式行为策略的简单2D强盗示例中说明了我们的方法和先前的工作。然后,我们证明我们的方法可以在离线RL的大多数D4RL基准任务上实现最先进的性能。
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We adapt the ideas underlying the success of Deep Q-Learning to the continuous action domain. We present an actor-critic, model-free algorithm based on the deterministic policy gradient that can operate over continuous action spaces. Using the same learning algorithm, network architecture and hyper-parameters, our algorithm robustly solves more than 20 simulated physics tasks, including classic problems such as cartpole swing-up, dexterous manipulation, legged locomotion and car driving. Our algorithm is able to find policies whose performance is competitive with those found by a planning algorithm with full access to the dynamics of the domain and its derivatives. We further demonstrate that for many of the tasks the algorithm can learn policies "end-to-end": directly from raw pixel inputs.
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The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.
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Mitotic activity is key for the assessment of malignancy in many tumors. Moreover, it has been demonstrated that the proportion of abnormal mitosis to normal mitosis is of prognostic significance. Atypical mitotic figures (MF) can be identified morphologically as having segregation abnormalities of the chromatids. In this work, we perform, for the first time, automatic subtyping of mitotic figures into normal and atypical categories according to characteristic morphological appearances of the different phases of mitosis. Using the publicly available MIDOG21 and TUPAC16 breast cancer mitosis datasets, two experts blindly subtyped mitotic figures into five morphological categories. Further, we set up a state-of-the-art object detection pipeline extending the anchor-free FCOS approach with a gated hierarchical subclassification branch. Our labeling experiment indicated that subtyping of mitotic figures is a challenging task and prone to inter-rater disagreement, which we found in 24.89% of MF. Using the more diverse MIDOG21 dataset for training and TUPAC16 for testing, we reached a mean overall average precision score of 0.552, a ROC AUC score of 0.833 for atypical/normal MF and a mean class-averaged ROC-AUC score of 0.977 for discriminating the different phases of cells undergoing mitosis.
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Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.
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安全至关重要的应用中神经网络(NNS)的患病率的增加,要求采用证明安全行为的方法。本文提出了一种向后的可及性方法,以安全验证神经反馈循环(NFLS),即具有NN控制策略的闭环系统。尽管最近的作品集中在远程达到NFL的安全认证策略上,但落后性能比远期策略具有优势,尤其是在避免障碍的情况下。先前的工作已经开发了用于无NNS系统的向后可及性分析的技术,但是由于其激活功能的非线性,反馈回路中的NNS存在唯一的问题,并且由于NN模型通常不可逆转。为了克服这些挑战,我们使用现有的NN分析工具有效地找到了对反射(BP)集的过度评估,即NN控制策略将将系统驱动到给定目标集的状态集。我们介绍了用于计算以馈电NN表示的控制策略的线性和非线性系统的BP过度评估的框架,并提出了计算有效的策略。我们使用各种模型的数值结果来展示所提出的算法,包括6D系统的安全认证。
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在同时定位和映射(SLAM)中,环路闭合检测(LCD)对于在识别先前访问的地方时最小化漂移至关重要。视觉袋(VBOW)一直是许多最先进的大满贯系统的LCD算法。它使用一组视觉功能来提供健壮的位置识别,但无法感知特征点之间的语义或空间关系。先前的工作主要集中在解决这些问题上,通过将VBOW与现场对象的语义和空间信息相结合。但是,他们无法利用局部视觉特征的空间信息,并且缺乏统一语义对象和视觉特征的结构,因此限制了两个组件之间的共生。本文提出了SymbiolCD2,该symbiolcd2创建了一个统一的图形结构,以在共生的方式集成语义对象和视觉特征。我们的新型基于图的LCD系统通过应用具有时间限制的Weisfeiler-Lehman图内核来利用统一的图结构,以稳健地预测循环闭合候选者。对所提出的系统的评估表明,具有结合语义对象和视觉特征的统一图结构提高了LCD预测精度,这说明了所提出的图形结构在这两个互补组件之间提供了强烈的共生。它还优于其他机器学习算法 - 例如SVM,决策树,随机森林,神经网络和基于GNN的图形匹配网络。此外,它在比最先进的SLAM系统的早期检测循环闭合候选方面表现出良好的性能,这表明统一图结构的扩展语义和空间意识会显着影响LCD的性能。
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通过将从地面视图摄像头拍摄到从卫星或飞机上拍摄的架空图像的图像,通过将代理定位在搜索区域内,将代理定位在搜索区域内,将代理定位在搜索区域中。尽管地面图像和架空图像之间的观点差异使得跨视图地理定位具有挑战性,但假设地面代理可以使用全景相机,则取得了重大进展。例如,我们先前的工作(WAG)引入了搜索区域离散化,训练损失和粒子过滤器加权的变化,从而实现了城市规模的全景跨视图地理定位。但是,由于其复杂性和成本,全景相机并未在现有机器人平台中广泛使用。非Panoramic跨视图地理定位更适用于机器人技术,但也更具挑战性。本文介绍了受限的FOV广泛地理定位(Rewag),这是一种跨视图地理定位方法,通过创建姿势吸引的嵌入并提供将粒子姿势纳入暹罗网络,将其概括为与标准的非填充地面摄像机一起使用,以供与标准的非卧型地面摄像机一起使用。 Rewag是一种神经网络和粒子滤波器系统,能够在GPS下的环境中全球定位移动代理,仅具有探测仪和90度FOV摄像机,其本地化精度与使用全景相机实现并提高本地化精度相似的定位精度与基线视觉变压器(VIT)方法相比,100倍。一个视频亮点,该视频亮点在https://youtu.be/u_obqrt8qce上展示了几十公里的测试路径上的收敛。
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子格式微型航空车(MAV)中的准确而敏捷的轨迹跟踪是具有挑战性的,因为机器人的小规模会引起大型模型不确定性,要求强大的反馈控制器,而快速的动力学和计算约束则阻止了计算上昂贵的策略的部署。在这项工作中,我们提出了一种在MIT SoftFly(一个子)MAV(0.7克)上进行敏捷和计算有效轨迹跟踪的方法。我们的策略采用了级联的控制方案,在该方案中,自适应态度控制器与受过训练的神经网络政策相结合,以模仿轨迹跟踪可靠的管模型模型预测控制器(RTMPC)。神经网络政策是使用我们最近的工作获得的,这使该政策能够保留RTMPC的稳健性,但以其计算成本的一小部分。我们通过实验评估我们的方法,即使在更具挑战性的操作中,达到均方根误差也低于1.8 cm,与我们先前的工作相比,最大位置误差减少了60%,并证明了对大型外部干扰的稳健性
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大型语言模型开发的最新进展导致公众访问最先进的预训练的语言模型(PLM),包括生成培训的预训练的变压器3(GPT-3)(GPT-3)和Transformers(来自Transformers)的双向编码器(伯特)。但是,实际上,对PLM的评估表明,在培训和开发的微调阶段,它们对对抗性攻击的敏感性。这种攻击可能导致错误的输出,模型生成的仇恨言论以及用户敏感信息的暴露。尽管现有的研究集中在PLM的培训或微调期间的对抗攻击上,但有关这两个发展阶段之间攻击的信息不足。在这项工作中,我们重点介绍了GPT-3公开发行的主要安全漏洞,并进一步研究了其他最先进的PLM中的这种漏洞。我们将工作限制在没有经过微调的预培训模型中。此外,我们强调了令牌距离最小化的扰动作为一种有效的对抗方法,绕过受监督和无监督的质量措施。遵循这种方法,在评估语义相似性时,我们观察到文本分类质量的显着降低。
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