A common assumption in causal inference from observational data is that there is no hidden confounding. Yet it is, in general, impossible to verify the presence of hidden confounding factors from a single dataset. Under the assumption of independent causal mechanisms underlying the data generating process, we demonstrate a way to detect unobserved confounders when having multiple observational datasets coming from different environments. We present a theory for testable conditional independencies that are only absent during hidden confounding and examine cases where we violate its assumptions: degenerate & dependent mechanisms, and faithfulness violations. Additionally, we propose a procedure to test these independencies and study its empirical finite-sample behavior using simulation studies and semi-synthetic data based on a real-world dataset. In most cases, our theory correctly predicts the presence of hidden confounding, particularly when the confounding bias is~large.
translated by 谷歌翻译
Surrogate algorithms such as Bayesian optimisation are especially designed for black-box optimisation problems with expensive objectives, such as hyperparameter tuning or simulation-based optimisation. In the literature, these algorithms are usually evaluated with synthetic benchmarks which are well established but have no expensive objective, and only on one or two real-life applications which vary wildly between papers. There is a clear lack of standardisation when it comes to benchmarking surrogate algorithms on real-life, expensive, black-box objective functions. This makes it very difficult to draw conclusions on the effect of algorithmic contributions and to give substantial advice on which method to use when. A new benchmark library, EXPObench, provides first steps towards such a standardisation. The library is used to provide an extensive comparison of six different surrogate algorithms on four expensive optimisation problems from different real-life applications. This has led to new insights regarding the relative importance of exploration, the evaluation time of the objective, and the used model. We also provide rules of thumb for which surrogate algorithm to use in which situation. A further contribution is that we make the algorithms and benchmark problem instances publicly available, contributing to more uniform analysis of surrogate algorithms. Most importantly, we include the performance of the six algorithms on all evaluated problem instances. This results in a unique new dataset that lowers the bar for researching new methods as the number of expensive evaluations required for comparison is significantly reduced.
translated by 谷歌翻译
In this paper we take the first steps in studying a new approach to synthesis of efficient communication schemes in multi-agent systems, trained via reinforcement learning. We combine symbolic methods with machine learning, in what is referred to as a neuro-symbolic system. The agents are not restricted to only use initial primitives: reinforcement learning is interleaved with steps to extend the current language with novel higher-level concepts, allowing generalisation and more informative communication via shorter messages. We demonstrate that this approach allow agents to converge more quickly on a small collaborative construction task.
translated by 谷歌翻译
Previous work has shown the potential of deep learning to predict renal obstruction using kidney ultrasound images. However, these image-based classifiers have been trained with the goal of single-visit inference in mind. We compare methods from video action recognition (i.e. convolutional pooling, LSTM, TSM) to adapt single-visit convolutional models to handle multiple visit inference. We demonstrate that incorporating images from a patient's past hospital visits provides only a small benefit for the prediction of obstructive hydronephrosis. Therefore, inclusion of prior ultrasounds is beneficial, but prediction based on the latest ultrasound is sufficient for patient risk stratification.
translated by 谷歌翻译
Workplace injuries are common in today's society due to a lack of adequately worn safety equipment. A system that only admits appropriately equipped personnel can be created to improve working conditions. The goal is thus to develop a system that will improve workers' safety using a camera that will detect the usage of Personal Protective Equipment (PPE). To this end, we collected and labeled appropriate data from several public sources, which have been used to train and evaluate several models based on the popular YOLOv4 object detector. Our focus, driven by a collaborating industrial partner, is to implement our system into an entry control point where workers must present themselves to obtain access to a restricted area. Combined with facial identity recognition, the system would ensure that only authorized people wearing appropriate equipment are granted access. A novelty of this work is that we increase the number of classes to five objects (hardhat, safety vest, safety gloves, safety glasses, and hearing protection), whereas most existing works only focus on one or two classes, usually hardhats or vests. The AI model developed provides good detection accuracy at a distance of 3 and 5 meters in the collaborative environment where we aim at operating (mAP of 99/89%, respectively). The small size of some objects or the potential occlusion by body parts have been identified as potential factors that are detrimental to accuracy, which we have counteracted via data augmentation and cropping of the body before applying PPE detection.
translated by 谷歌翻译
Storytelling and narrative are fundamental to human experience, intertwined with our social and cultural engagement. As such, researchers have long attempted to create systems that can generate stories automatically. In recent years, powered by deep learning and massive data resources, automatic story generation has shown significant advances. However, considerable challenges, like the need for global coherence in generated stories, still hamper generative models from reaching the same storytelling ability as human narrators. To tackle these challenges, many studies seek to inject structured knowledge into the generation process, which is referred to as structure knowledge-enhanced story generation. Incorporating external knowledge can enhance the logical coherence among story events, achieve better knowledge grounding, and alleviate over-generalization and repetition problems in stories. This survey provides the latest and comprehensive review of this research field: (i) we present a systematical taxonomy regarding how existing methods integrate structured knowledge into story generation; (ii) we summarize involved story corpora, structured knowledge datasets, and evaluation metrics; (iii) we give multidimensional insights into the challenges of knowledge-enhanced story generation and cast light on promising directions for future study.
translated by 谷歌翻译
Automated synthesis of provably correct controllers for cyber-physical systems is crucial for deploying these systems in safety-critical scenarios. However, their hybrid features and stochastic or unknown behaviours make this synthesis problem challenging. In this paper, we propose a method for synthesizing controllers for Markov jump linear systems (MJLSs), a particular class of cyber-physical systems, that certifiably satisfy a requirement expressed as a specification in probabilistic computation tree logic (PCTL). An MJLS consists of a finite set of linear dynamics with unknown additive disturbances, where jumps between these modes are governed by a Markov decision process (MDP). We consider both the case where the transition function of this MDP is given by probability intervals or where it is completely unknown. Our approach is based on generating a finite-state abstraction which captures both the discrete and the continuous behaviour of the original system. We formalise such abstraction as an interval Markov decision process (iMDP): intervals of transition probabilities are computed using sampling techniques from the so-called "scenario approach", resulting in a probabilistically sound approximation of the MJLS. This iMDP abstracts both the jump dynamics between modes, as well as the continuous dynamics within the modes. To demonstrate the efficacy of our technique, we apply our method to multiple realistic benchmark problems, in particular, temperature control, and aerial vehicle delivery problems.
translated by 谷歌翻译
在本文中,我们提出了一种自适应方法,用于通过正交过程进行聚类和可视化数据。从使用扩散地图框架代表的数据点开始,该方法通过应用受Gromov-Wasserstein距离启发的反馈机制自适应地增加了群集的正交性。这种机制迭代地增加了光谱差距,并完善了数据的正交性,以实现具有高特异性的聚类。通过使用扩散地图框架并使用过渡概率表示数据点之间的关系,该方法相对于基础距离,数据中的噪声和随机初始化都是可靠的。我们证明该方法将全球收敛到某些参数值的唯一固定点。我们还提出了一种相关方法,其中要求马尔可夫进程中的过渡概率是双重随机的,在这种情况下,该方法对非convex优化问题产生了最小化器。我们将该方法应用于来自生物药物制造的冷冻电子显微镜图像数据,在那里我们可以确认与治疗功效有关的生物学相关见解。我们考虑了一个具有基因包装形态变化的示例,并确认该方法会产生与人类专家分类一致的生物学意义的聚类结果。
translated by 谷歌翻译
联合学习(FL)是数据是私人且敏感时的有前途的分布式学习框架。但是,当数据是异质且非独立且相同分布的(非IID)时,此框架中最新的解决方案并不是最佳的。我们提出了一种实用且强大的佛罗里达州个性化方法,该方法通过平衡探索和利用几种全球模型来适应异质和非IID数据。为了实现我们的个性化目标,我们使用了专家(MOE)的混合,这些专家(MOE)学会了分组彼此相似的客户,同时更有效地使用全球模型。我们表明,与病理非IID环境中的本地模型相比,我们的方法的准确性高达29.78%,高达4.38%,即使我们在IID环境中调整了方法。
translated by 谷歌翻译
本文建立了一种新颖的通用和平台 - 无话会风险感知路径规划框架,其基于经典$ D ^ * $ Lite规划仪,路径设计专注于安全性和效率。该计划者生成一个网格图,其中占用/自由/未知空间用不同的遍历成本表示。在这种情况下,在这种情况下呈现,将遍历成本添加到接近占用的未知体素。算法实现也通过动态网格图来增强,具有在机器人操作期间更新和扩展的新颖能力,从而增加了使命的整体安全性,并且适用于勘探和搜索和救援任务。在生成的网格图中,$ d ^ * $ lite能够规划一个更安全的路径,具有最小的遍历成本。所提出的路径规划框架适用于分别生成2D和3D路径,以及在3D情况下,在3D情况下,用一个体素高度产生网格以计划2D路径,这是区分之间的主要因素2D和3D路径规划。在Quadcopter平台和波士顿动力学点腿机器人的多种仿真和实际场实验中广泛评估所提出的新型路径规划方案的功效。
translated by 谷歌翻译