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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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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在可能被GPS贬低的环境中准确估计机器人相对于彼此相对的位置的能力对于执行协作任务至关重要。由于超宽带无线电等技术,因此以低成本的价格获得了代理范围测量值。但是,使用多代理系统中的范围测量的三维相对位置估计的任务遭受了未观察到的。该字母为相对位置的可观察性提供了足够的条件,并使用仅具有范围测量的简单框架,加速度计,速率陀螺仪和磁力计满足条件。该框架已在模拟和实验中进行了测试,其中使用便宜的现成硬件实现了40-50 cm的定位精度。
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在解决现实世界机器人状态估计问题时,测量异常值是不可避免的。存在大量强大的损失功能(RLF),以减轻异常值的影响,包括新开发的自适应方法,这些方法不需要参数调整。所有这些方法都假设残差遵循零均值的高斯样分布。但是,在多元问题中,残差通常被定义为标准,规范遵循具有非零模式值的卡式分布。这会产生“模式差距”,从而影响现有RLF的收敛速率和准确性。提出的方法“自适应MB”通过首先使用自适应卡式分布估算残差的模式来解释这一差距。将现有的自适应加权方案应用于大于模式的残留物,从而在两个基本状态估计问题,点云对齐和平均姿势中导致更强的性能和更快的收敛时间。
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当考虑了许多提升功能时,从数据近似数据在数值上具有挑战性。即使是低维系统也可以在高维升空的空间中产生不稳定或不良条件的结果。在本文中,具有控制的扩展动态模式分解(DMD)和DMD,两种用于近似Koopman运算符的方法,被重新列为线性矩阵不等式约束的凸优化问题。然后将渐近稳定性约束和系统规范正规化器作为改善Koopman操作员的数值条件的方法合并。具体而言,H-Infinity Narm用于惩罚Koopman系统的投入输出增益。然后将加权功能应用于特定频率下的系统增益。这些约束和正规化器将双线性矩阵不等式的约束引入回归问题,这些问题是通过求解凸优化问题的序列来处理的。实验结果使用来自飞机疲劳结构测试钻机和软机器人臂的数据突出了所提出的回归方法的优势。
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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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We present AI-SDC, an integrated suite of open source Python tools to facilitate Statistical Disclosure Control (SDC) of Machine Learning (ML) models trained on confidential data prior to public release. AI-SDC combines (i) a SafeModel package that extends commonly used ML models to provide ante-hoc SDC by assessing the vulnerability of disclosure posed by the training regime; and (ii) an Attacks package that provides post-hoc SDC by rigorously assessing the empirical disclosure risk of a model through a variety of simulated attacks after training. The AI-SDC code and documentation are available under an MIT license at https://github.com/AI-SDC/AI-SDC.
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Artificial intelligence methods including deep neural networks (DNN) can provide rapid molecular classification of tumors from routine histology with accuracy that matches or exceeds human pathologists. Discerning how neural networks make their predictions remains a significant challenge, but explainability tools help provide insights into what models have learned when corresponding histologic features are poorly defined. Here, we present a method for improving explainability of DNN models using synthetic histology generated by a conditional generative adversarial network (cGAN). We show that cGANs generate high-quality synthetic histology images that can be leveraged for explaining DNN models trained to classify molecularly-subtyped tumors, exposing histologic features associated with molecular state. Fine-tuning synthetic histology through class and layer blending illustrates nuanced morphologic differences between tumor subtypes. Finally, we demonstrate the use of synthetic histology for augmenting pathologist-in-training education, showing that these intuitive visualizations can reinforce and improve understanding of histologic manifestations of tumor biology.
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通用数据模型解决了标准化电子健康记录(EHR)数据的许多挑战,但无法将其集成深度表型所需的资源。开放的生物学和生物医学本体论(OBO)铸造本体论提供了可用于生物学知识的语义计算表示,并能够整合多种生物医学数据。但是,将EHR数据映射到OBO Foundry本体论需要大量的手动策展和域专业知识。我们介绍了一个框架,用于将观察性医学成果合作伙伴关系(OMOP)标准词汇介绍给OBO铸造本体。使用此框架,我们制作了92,367条条件,8,615种药物成分和10,673个测量结果的映射。域专家验证了映射准确性,并且在24家医院进行检查时,映射覆盖了99%的条件和药物成分和68%的测量结果。最后,我们证明OMOP2OBO映射可以帮助系统地识别可能受益于基因检测的未诊断罕见病患者。
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目的:本研究评估了市售可解释的AI算法在增强临床医生在胸部X射线(CXR)上鉴定肺癌的能力的影响。设计:这项回顾性研究评估了11位临床医生在胸部X光片中检测肺癌的表现,并在有和没有市售的AI算法的帮助下(红点,观察到),预测CXRS可疑的肺癌。根据临床确定的诊断评估了临床医生的表现。设置:该研究分析了NHS医院的匿名患者数据;该数据集由成年患者(18岁及以上)的400张胸部X光片组成,他们在2020年进行了CXR,并提供相应的临床文本报告。参与者:由11位临床医生(放射科医生,放射科医生受训者和报告射线照相师)组成的读者小组参加。主要结果指标:临床医生在CXR上检测肺癌的总体准确性,敏感性,特异性和精度,有或没有AI输入。还评估了有或没有AI输入的临床医生与绩效标准偏差之间的协议率。结果:临床医生对AI算法的使用导致肺部肿瘤检测的总体性能提高,从而达到了在CXR上鉴定出的肺癌的总体增长17.4% ,分别增加了13%和13%的阶段1和2期肺癌的检测,以及临床医生表现的标准化。结论:这项研究在AI算法的临床实用性方面表现出了巨大的希望,可以通过整体改善读者表现来改善早期肺癌诊断和促进健康平等,而不会影响下游成像资源。
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