基于图神经网络(GNN)方法已饱和推荐系统的领域。这些系统的收益很大,显示了通过网络结构解释数据的优势。但是,尽管在建议任务中使用图形结构有明显的好处,但这种表示形式也带来了新的挑战,这些挑战加剧了缓解算法偏见的复杂性。当将GNN集成到下游任务中时,例如建议,缓解偏差可能会变得更加困难。此外,将现有的公平促进方法应用于大型现实世界数据集的棘手性对缓解尝试更加严重的限制。我们的工作着手通过采用现有方法来促进图形上的个人公平性并将其扩展以支持Mini批次或基于子样本的培训,从而填补了这一空白下游建议任务。我们评估了两种流行的GNN方法:图形卷积网络(GCN),该方法在整个图上进行训练,以及使用概率随机步行的图形,以创建用于迷你批次训练的子图,并评估子采样对个人公平性的影响。我们实施了一个由Dong等人提出的称为\ textit {redress}的个人公平概念,该概念使用等级优化来学习单个公平节点或项目,嵌入。我们在两个现实世界数据集上进行了经验证明,图形不仅能够达到可比的精度,而且与GCN模型相比,还可以提高公平性。这些发现对个人的公平促进,GNN和下游形式产生了影响,推荐系统,表明小批量培训通过允许当地的细微努力指导代表性学习中的公平促进过程来促进个人公平促进。
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Machine learning methods have seen increased application to geospatial environmental problems, such as precipitation nowcasting, haze forecasting, and crop yield prediction. However, many of the machine learning methods applied to mosquito population and disease forecasting do not inherently take into account the underlying spatial structure of the given data. In our work, we apply a spatially aware graph neural network model consisting of GraphSAGE layers to forecast the presence of West Nile virus in Illinois, to aid mosquito surveillance and abatement efforts within the state. More generally, we show that graph neural networks applied to irregularly sampled geospatial data can exceed the performance of a range of baseline methods including logistic regression, XGBoost, and fully-connected neural networks.
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Electronic Health Records (EHRs) hold detailed longitudinal information about each patient's health status and general clinical history, a large portion of which is stored within the unstructured text. Temporal modelling of this medical history, which considers the sequence of events, can be used to forecast and simulate future events, estimate risk, suggest alternative diagnoses or forecast complications. While most prediction approaches use mainly structured data or a subset of single-domain forecasts and outcomes, we processed the entire free-text portion of EHRs for longitudinal modelling. We present Foresight, a novel GPT3-based pipeline that uses NER+L tools (i.e. MedCAT) to convert document text into structured, coded concepts, followed by providing probabilistic forecasts for future medical events such as disorders, medications, symptoms and interventions. Since large portions of EHR data are in text form, such an approach benefits from a granular and detailed view of a patient while introducing modest additional noise. On tests in two large UK hospitals (King's College Hospital, South London and Maudsley) and the US MIMIC-III dataset precision@10 of 0.80, 0.81 and 0.91 was achieved for forecasting the next biomedical concept. Foresight was also validated on 34 synthetic patient timelines by 5 clinicians and achieved relevancy of 97% for the top forecasted candidate disorder. Foresight can be easily trained and deployed locally as it only requires free-text data (as a minimum). As a generative model, it can simulate follow-on disorders, medications and interventions for as many steps as required. Foresight is a general-purpose model for biomedical concept modelling that can be used for real-world risk estimation, virtual trials and clinical research to study the progression of diseases, simulate interventions and counterfactuals, and for educational purposes.
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Because of their close relationship with humans, non-human apes (chimpanzees, bonobos, gorillas, orangutans, and gibbons, including siamangs) are of great scientific interest. The goal of understanding their complex behavior would be greatly advanced by the ability to perform video-based pose tracking. Tracking, however, requires high-quality annotated datasets of ape photographs. Here we present OpenApePose, a new public dataset of 71,868 photographs, annotated with 16 body landmarks, of six ape species in naturalistic contexts. We show that a standard deep net (HRNet-W48) trained on ape photos can reliably track out-of-sample ape photos better than networks trained on monkeys (specifically, the OpenMonkeyPose dataset) and on humans (COCO) can. This trained network can track apes almost as well as the other networks can track their respective taxa, and models trained without one of the six ape species can track the held out species better than the monkey and human models can. Ultimately, the results of our analyses highlight the importance of large specialized databases for animal tracking systems and confirm the utility of our new ape database.
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Knowledge of the symmetries of reinforcement learning (RL) systems can be used to create compressed and semantically meaningful representations of a low-level state space. We present a method of automatically detecting RL symmetries directly from raw trajectory data without requiring active control of the system. Our method generates candidate symmetries and trains a recurrent neural network (RNN) to discriminate between the original trajectories and the transformed trajectories for each candidate symmetry. The RNN discriminator's accuracy for each candidate reveals how symmetric the system is under that transformation. This information can be used to create high-level representations that are invariant to all symmetries on a dataset level and to communicate properties of the RL behavior to users. We show in experiments on two simulated RL use cases (a pusher robot and a UAV flying in wind) that our method can determine the symmetries underlying both the environment physics and the trained RL policy.
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Hidden parameters are latent variables in reinforcement learning (RL) environments that are constant over the course of a trajectory. Understanding what, if any, hidden parameters affect a particular environment can aid both the development and appropriate usage of RL systems. We present an unsupervised method to map RL trajectories into a feature space where distance represents the relative difference in system behavior due to hidden parameters. Our approach disentangles the effects of hidden parameters by leveraging a recurrent neural network (RNN) world model as used in model-based RL. First, we alter the standard world model training algorithm to isolate the hidden parameter information in the world model memory. Then, we use a metric learning approach to map the RNN memory into a space with a distance metric approximating a bisimulation metric with respect to the hidden parameters. The resulting disentangled feature space can be used to meaningfully relate trajectories to each other and analyze the hidden parameter. We demonstrate our approach on four hidden parameters across three RL environments. Finally we present two methods to help identify and understand the effects of hidden parameters on systems.
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Producing high-quality forecasts of key climate variables such as temperature and precipitation on subseasonal time scales has long been a gap in operational forecasting. Recent studies have shown promising results using machine learning (ML) models to advance subseasonal forecasting (SSF), but several open questions remain. First, several past approaches use the average of an ensemble of physics-based forecasts as an input feature of these models. However, ensemble forecasts contain information that can aid prediction beyond only the ensemble mean. Second, past methods have focused on average performance, whereas forecasts of extreme events are far more important for planning and mitigation purposes. Third, climate forecasts correspond to a spatially-varying collection of forecasts, and different methods account for spatial variability in the response differently. Trade-offs between different approaches may be mitigated with model stacking. This paper describes the application of a variety of ML methods used to predict monthly average precipitation and two meter temperature using physics-based predictions (ensemble forecasts) and observational data such as relative humidity, pressure at sea level, or geopotential height, two weeks in advance for the whole continental United States. Regression, quantile regression, and tercile classification tasks using linear models, random forests, convolutional neural networks, and stacked models are considered. The proposed models outperform common baselines such as historical averages (or quantiles) and ensemble averages (or quantiles). This paper further includes an investigation of feature importance, trade-offs between using the full ensemble or only the ensemble average, and different modes of accounting for spatial variability.
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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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紧张的机器人由刚性杆和柔性电缆组成,表现出高强度对重的比率和极端变形,使它们能够驾驭非结构化的地形,甚至可以在严酷的冲击力上生存。但是,由于其高维,复杂的动态和耦合体系结构,它们很难控制。基于物理学的仿真是制定运动策略的途径,然后可以将其转移到真实的机器人中,但是建模时态机器人是一项复杂的任务,因此模拟会经历大量的SIM2REAL间隙。为了解决这个问题,本文介绍了台词机器人的真实2SIM2REAL策略。该策略是基于差异物理引擎的,可以在真正的机器人(即离线测量和一个随机轨迹)中进行有限的数据进行训练,并达到足够高的精度以发现可转移的运动策略。除了整体管道之外,这项工作的主要贡献包括在接触点处计算非零梯度,损失函数和轨迹分割技术,该技术避免了训练期间梯度评估的冲突。在实际的3杆张力机器人上证明并评估了所提出的管道。
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在本文中,我们介绍Bayesldm,这是一个用于贝叶斯纵向数据建模的系统,该系统由高级建模语言组成,具有针对复杂的多变量时间序列数据建模的特定功能,并与编译器相结合,可以生成优化的概率程序代码,以在指定模型中执行指定的推理。 Bayesldm支持贝叶斯网络模型的建模,其特定关注动态贝叶斯网络(DBN)的高效,声明性规范。 Bayesldm编译器将模型规范与可用数据和输出代码相结合,用于执行贝叶斯推断,以同时处理丢失的数据,同时处理未知模型参数。这些功能有可能通过抽象产生计算有效的概率推断代码的过程来显着加速域中的迭代建模工作流,这些迭代建模工作流程涉及复杂纵向数据的分析。我们描述了Bayesldm系统组件,评估表示和推理优化的效率,并提供了该系统在分析异质和部分观察到的移动健康数据的应用示例。
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