This paper proposes a new algorithm for an automatic variable selection procedure in High Dimensional Graphical Models. The algorithm selects the relevant variables for the node of interest on the basis of mutual information. Several contributions in literature have investigated the use of mutual information in selecting the appropriate number of relevant features in a large data-set, but most of them have focused on binary outcomes or required high computational effort. The algorithm here proposed overcomes these drawbacks as it is an extension of Chow and Liu's algorithm. Once, the probabilistic structure of a High Dimensional Graphical Model is determined via the said algorithm, the best path-step, including variables with the most explanatory/predictive power for a variable of interest, is determined via the computation of the entropy coefficient of determination. The latter, being based on the notion of (symmetric) Kullback-Leibler divergence, turns out to be closely connected to the mutual information of the involved variables. The application of the algorithm to a wide range of real-word and publicly data-sets has highlighted its potential and greater effectiveness compared to alternative extant methods.
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Specular microscopy assessment of the human corneal endothelium (CE) in Fuchs' dystrophy is challenging due to the presence of dark image regions called guttae. This paper proposes a UNet-based segmentation approach that requires minimal post-processing and achieves reliable CE morphometric assessment and guttae identification across all degrees of Fuchs' dystrophy. We cast the segmentation problem as a regression task of the cell and gutta signed distance maps instead of a pixel-level classification task as typically done with UNets. Compared to the conventional UNet classification approach, the distance-map regression approach converges faster in clinically relevant parameters. It also produces morphometric parameters that agree with the manually-segmented ground-truth data, namely the average cell density difference of -41.9 cells/mm2 (95% confidence interval (CI) [-306.2, 222.5]) and the average difference of mean cell area of 14.8 um2 (95% CI [-41.9, 71.5]). These results suggest a promising alternative for CE assessment.
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NLP研究的最新突破,例如变压器模型的出现,无疑促进了多项任务的重大进步。但是,很少有作品研究其评估策略的鲁棒性和解释性问题。在这项工作中,我们研究了高性能预训练的语言模型的行为,重点是视觉词汇的语义相似性。首先,我们满足了对可解释的评估指标的需求,这是理解检索实例的概念质量所必需的。我们提出的指标在地方和全球层面提供了宝贵的见解,展示了广泛使用方法的无能。其次,对显着查询语义的对抗性干预措施暴露了不透明指标的漏洞,并在学习的语言表示中突出了模式。
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制定了具有机器学习模拟(骆驼)项目的宇宙学和天体物理学,通过数千名宇宙的流体动力模拟和机器学习将宇宙学与天体物理学结合起来。骆驼包含4,233个宇宙学仿真,2,049个n-body和2,184个最先进的流体动力模拟,在参数空间中采样巨大的体积。在本文中,我们介绍了骆驼公共数据发布,描述了骆驼模拟的特性和由它们产生的各种数据产品,包括光环,次麦,银河系和空隙目录,功率谱,Bispectra,Lyman - $ \ Alpha $光谱,概率分布函数,光环径向轮廓和X射线光子列表。我们还释放了超过骆驼 - 山姆的数十亿个星系的目录:与Santa Cruz半分析模型相结合的大量N身体模拟。我们释放包含350多个Terabytes的所有数据,并包含143,922个快照,数百万光环,星系和摘要统计数据。我们提供有关如何访问,下载,读取和处理数据AT \ URL {https://camels.readthedocs.io}的进一步技术详细信息。
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最近的一些研究描述了深层卷积神经网络,以诊断与人类专家相似甚至卓越表现的乳腺癌乳腺癌。最好的技术之一可以进行两种转移学习:第一个使用在自然图像上训练的模型来创建“补丁分类器”,该模型将小型子图表分类;第二个使用补丁分类器来扫描整个乳房X线照片并创建“单视图全图分类器”。我们建议进行第三次转移学习,以获取“两视图分类器”,以使用两种乳房X线摄影视图:双侧颅颅和中外侧倾斜。我们使用效率网络作为模型的基础。我们使用CBIS-DDSM数据集“端到端”训练整个系统。为了确保统计鲁棒性,我们使用以下方式两次测试系统,(a)5倍交叉验证; (b)数据集的原始培训/测试部门。我们的技术使用5倍的交叉验证达到0.9344的AUC(在ROC的误差率相等的误差率下,准确性,灵敏度和特异性为85.13%)。据我们所知,使用原始的数据集除法,我们的技术达到了0.8483,尽管我们知道的最高的AUC在此问题上,尽管每项工作的测试条件上的细微差异不允许进行准确的比较。推理代码和模型可在https://github.com/dpetrini/two-views-classifier上获得
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医疗AI通过支持基于证据的医学实践,个性化患者治疗,降低成本以及改善提供者和患者体验,推进医疗保健的巨大潜力。我们认为解锁此潜力需要一种系统的方法来衡量在大规模异构数据上的医疗AI模型的性能。为了满足这种需求,我们正在建立Medperf,这是一个开放的框架,用于在医疗领域的基准测试机器学习。 Medperf将使联合评估能够将模型安全地分配给不同的评估设施,从而赋予医疗组织在高效和人类监督过程中评估和验证AI模型的性能,同时优先考虑隐私。我们描述了当前的挑战医疗保健和AI社区面临,需要开放平台,Medperf的设计理念,其目前的实施状态和我们的路线图。我们呼吁研究人员和组织加入我们创建Medperf开放基准平台。
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While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.
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Attention mechanisms form a core component of several successful deep learning architectures, and are based on one key idea: ''The output depends only on a small (but unknown) segment of the input.'' In several practical applications like image captioning and language translation, this is mostly true. In trained models with an attention mechanism, the outputs of an intermediate module that encodes the segment of input responsible for the output is often used as a way to peek into the `reasoning` of the network. We make such a notion more precise for a variant of the classification problem that we term selective dependence classification (SDC) when used with attention model architectures. Under such a setting, we demonstrate various error modes where an attention model can be accurate but fail to be interpretable, and show that such models do occur as a result of training. We illustrate various situations that can accentuate and mitigate this behaviour. Finally, we use our objective definition of interpretability for SDC tasks to evaluate a few attention model learning algorithms designed to encourage sparsity and demonstrate that these algorithms help improve interpretability.
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Many challenging reinforcement learning (RL) problems require designing a distribution of tasks that can be applied to train effective policies. This distribution of tasks can be specified by the curriculum. A curriculum is meant to improve the results of learning and accelerate it. We introduce Success Induced Task Prioritization (SITP), a framework for automatic curriculum learning, where a task sequence is created based on the success rate of each task. In this setting, each task is an algorithmically created environment instance with a unique configuration. The algorithm selects the order of tasks that provide the fastest learning for agents. The probability of selecting any of the tasks for the next stage of learning is determined by evaluating its performance score in previous stages. Experiments were carried out in the Partially Observable Grid Environment for Multiple Agents (POGEMA) and Procgen benchmark. We demonstrate that SITP matches or surpasses the results of other curriculum design methods. Our method can be implemented with handful of minor modifications to any standard RL framework and provides useful prioritization with minimal computational overhead.
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This paper presents a solution to the GenChal 2022 shared task dedicated to feedback comment generation for writing learning. In terms of this task given a text with an error and a span of the error, a system generates an explanatory note that helps the writer (language learner) to improve their writing skills. Our solution is based on fine-tuning the T5 model on the initial dataset augmented according to syntactical dependencies of the words located within indicated error span. The solution of our team "nigula" obtained second place according to manual evaluation by the organizers.
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