已经开发了各种方法来结合多组结果的推理,以在集合和共识聚类文献中进行无监督的聚类。从几个候选聚类模型中的一个“最佳”模型报告结果的方法通常忽略了由模型选择产生的不确定性,并且导致对所选择的特定模型和参数敏感的推论,以及制作的假设,尤其是在小样本中所做的假设。尺寸或小簇尺寸。贝叶斯模型平均(BMA)是一种在多种模型中结合结果的流行方法,这些模型在这种情况下提供了一些有吸引力的好处,包括对组合集群结构的概率解释和基于模型的不确定性的量化。在这项工作中,我们介绍了ClusterBMA,该方法可以通过多种无监督聚类算法进行加权模型平均。我们将聚类内部验证标准的组合用作后验模型概率的新近似值,以加权每个模型的结果。从代表跨模型的聚类溶液的加权平均值的组合后相似性矩阵,我们应用对称的单纯形矩阵分解来计算最终的概率群集分配。此方法在随附的R软件包中实现。我们通过案例研究探索这种方法的性能,该案例研究旨在根据脑电图(EEG)数据识别个体的概率簇。我们还使用仿真数据集探索所提出的技术识别稳健的集成簇具有不同级别的集成簇,并在子组之间的分离水平变化,并且模型之间的簇数量变化。
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With the rise in high resolution remote sensing technologies there has been an explosion in the amount of data available for forest monitoring, and an accompanying growth in artificial intelligence applications to automatically derive forest properties of interest from these datasets. Many studies use their own data at small spatio-temporal scales, and demonstrate an application of an existing or adapted data science method for a particular task. This approach often involves intensive and time-consuming data collection and processing, but generates results restricted to specific ecosystems and sensor types. There is a lack of widespread acknowledgement of how the types and structures of data used affects performance and accuracy of analysis algorithms. To accelerate progress in the field more efficiently, benchmarking datasets upon which methods can be tested and compared are sorely needed. Here, we discuss how lack of standardisation impacts confidence in estimation of key forest properties, and how considerations of data collection need to be accounted for in assessing method performance. We present pragmatic requirements and considerations for the creation of rigorous, useful benchmarking datasets for forest monitoring applications, and discuss how tools from modern data science can improve use of existing data. We list a set of example large-scale datasets that could contribute to benchmarking, and present a vision for how community-driven, representative benchmarking initiatives could benefit the field.
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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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Estimation algorithms, such as the sliding window filter, produce an estimate and uncertainty of desired states. This task becomes challenging when the problem involves unobservable states. In these situations, it is critical for the algorithm to ``know what it doesn't know'', meaning that it must maintain the unobservable states as unobservable during algorithm deployment. This letter presents general requirements for maintaining consistency in sliding window filters involving unobservable states. The value of these requirements when designing a navigation solution is experimentally shown within the context of visual-inertial SLAM making use of IMU preintegration.
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The proliferation of unmanned aircraft systems (UAS) has caused airspace regulation authorities to examine the interoperability of these aircraft with collision avoidance systems initially designed for large transport category aircraft. Limitations in the currently mandated TCAS led the Federal Aviation Administration to commission the development of a new solution, the Airborne Collision Avoidance System X (ACAS X), designed to enable a collision avoidance capability for multiple aircraft platforms, including UAS. While prior research explored using deep reinforcement learning algorithms (DRL) for collision avoidance, DRL did not perform as well as existing solutions. This work explores the benefits of using a DRL collision avoidance system whose parameters are tuned using a surrogate optimizer. We show the use of a surrogate optimizer leads to DRL approach that can increase safety and operational viability and support future capability development for UAS collision avoidance.
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Recent advances in operator learning theory have improved our knowledge about learning maps between infinite dimensional spaces. However, for large-scale engineering problems such as concurrent multiscale simulation for mechanical properties, the training cost for the current operator learning methods is very high. The article presents a thorough analysis on the mathematical underpinnings of the operator learning paradigm and proposes a kernel learning method that maps between function spaces. We first provide a survey of modern kernel and operator learning theory, as well as discuss recent results and open problems. From there, the article presents an algorithm to how we can analytically approximate the piecewise constant functions on R for operator learning. This implies the potential feasibility of success of neural operators on clustered functions. Finally, a k-means clustered domain on the basis of a mechanistic response is considered and the Lippmann-Schwinger equation for micro-mechanical homogenization is solved. The article briefly discusses the mathematics of previous kernel learning methods and some preliminary results with those methods. The proposed kernel operator learning method uses graph kernel networks to come up with a mechanistic reduced order method for multiscale homogenization.
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Deep Learning models are easily disturbed by variations in the input images that were not seen during training, resulting in unpredictable behaviours. Such Out-of-Distribution (OOD) images represent a significant challenge in the context of medical image analysis, where the range of possible abnormalities is extremely wide, including artifacts, unseen pathologies, or different imaging protocols. In this work, we evaluate various uncertainty frameworks to detect OOD inputs in the context of Multiple Sclerosis lesions segmentation. By implementing a comprehensive evaluation scheme including 14 sources of OOD of various nature and strength, we show that methods relying on the predictive uncertainty of binary segmentation models often fails in detecting outlying inputs. On the contrary, learning to segment anatomical labels alongside lesions highly improves the ability to detect OOD inputs.
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We propose KnowGL, a tool that allows converting text into structured relational data represented as a set of ABox assertions compliant with the TBox of a given Knowledge Graph (KG), such as Wikidata. We address this problem as a sequence generation task by leveraging pre-trained sequence-to-sequence language models, e.g. BART. Given a sentence, we fine-tune such models to detect pairs of entity mentions and jointly generate a set of facts consisting of the full set of semantic annotations for a KG, such as entity labels, entity types, and their relationships. To showcase the capabilities of our tool, we build a web application consisting of a set of UI widgets that help users to navigate through the semantic data extracted from a given input text. We make the KnowGL model available at https://huggingface.co/ibm/knowgl-large.
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最近的高精度亚次光学光学扫描仪的开发允许将3D键盘检测器和功能描述符在海底环境中的点云扫描上利用。但是,文献缺乏一项全面的调查,无法确定在这些挑战和新颖的环境中使用的检测器和描述符的最佳组合。本文旨在使用使用商业水下激光扫描仪收集的具有挑战性的现场数据集确定最佳的检测器/描述符对。此外,研究表明,合并纹理信息扩展几何特征为合成数据集的特征匹配增添了鲁棒性。本文还提出了一种与水下激光扫描融合图像以产生有色点云的新方法,该方法用于研究6D点云描述符的有效性。
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深度神经网络已成为3D医学图像自动分割的金标准方法。然而,由于缺乏对所提供的结果评估可理解的不确定性评估,他们被临床医生的全部接受仍然受到阻碍。量化其不确定性的大多数方法,例如流行的蒙特卡洛辍学物,仅限于在体素水平上预测的某种不确定性度量。除了与真正的医学不确定性无关紧要之外,这在临床上并不令人满意,因为大多数感兴趣的对象(例如,脑部病变)是由素食组成的,其整体相关性可能不会简单地减少其个人不确定性的总和或平均值。在这项工作中,我们建议使用创新的图形神经网络方法超越体素评估,并从蒙特卡洛辍学模型的输出中训练。该网络允许融合体素不确定性的三个估计量:熵,方差和模型的置信度;并且可以应用于任何病变,无论其形状或大小如何。我们证明了我们方法对多发性硬化病变的任务的不确定性估计的优势。
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