由于它们对运动模糊和在弱光和高动态范围条件下的高度鲁棒性的韧性,事件摄像机有望成为对未来火星直升机任务的基于视觉探索的传感器。但是,现有的基于事件的视觉惯性进程(VIO)算法要么患有高跟踪误差,要么是脆弱的,因为它们无法应对由于无法预料的跟踪损失或其他效果而导致的显着深度不确定性。在这项工作中,我们介绍了EKLT-VIO,该工作通过将基于事件的最新前端与基于过滤器的后端相结合来解决这两种限制。这使得不确定性的准确和强大,超过了基于事件和基于框架的VIO算法在挑战性基准上的算法32%。此外,我们在悬停的条件(胜过现有事件的方法)以及新近收集的类似火星和高动态范围的新序列中表现出准确的性能,而现有的基于框架的方法失败了。在此过程中,我们表明基于事件的VIO是基于视觉的火星探索的前进道路。
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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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Understanding customer feedback is becoming a necessity for companies to identify problems and improve their products and services. Text classification and sentiment analysis can play a major role in analyzing this data by using a variety of machine and deep learning approaches. In this work, different transformer-based models are utilized to explore how efficient these models are when working with a German customer feedback dataset. In addition, these pre-trained models are further analyzed to determine if adapting them to a specific domain using unlabeled data can yield better results than off-the-shelf pre-trained models. To evaluate the models, two downstream tasks from the GermEval 2017 are considered. The experimental results show that transformer-based models can reach significant improvements compared to a fastText baseline and outperform the published scores and previous models. For the subtask Relevance Classification, the best models achieve a micro-averaged $F1$-Score of 96.1 % on the first test set and 95.9 % on the second one, and a score of 85.1 % and 85.3 % for the subtask Polarity Classification.
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Purpose: Hard-to-interpret Black-box Machine Learning (ML) were often used for early Alzheimer's Disease (AD) detection. Methods: To interpret eXtreme Gradient Boosting (XGBoost), Random Forest (RF), and Support Vector Machine (SVM) black-box models a workflow based on Shapley values was developed. All models were trained on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset and evaluated for an independent ADNI test set, as well as the external Australian Imaging and Lifestyle flagship study of Ageing (AIBL), and Open Access Series of Imaging Studies (OASIS) datasets. Shapley values were compared to intuitively interpretable Decision Trees (DTs), and Logistic Regression (LR), as well as natural and permutation feature importances. To avoid the reduction of the explanation validity caused by correlated features, forward selection and aspect consolidation were implemented. Results: Some black-box models outperformed DTs and LR. The forward-selected features correspond to brain areas previously associated with AD. Shapley values identified biologically plausible associations with moderate to strong correlations with feature importances. The most important RF features to predict AD conversion were the volume of the amygdalae, and a cognitive test score. Good cognitive test performances and large brain volumes decreased the AD risk. The models trained using cognitive test scores significantly outperformed brain volumetric models ($p<0.05$). Cognitive Normal (CN) vs. AD models were successfully transferred to external datasets. Conclusion: In comparison to previous work, improved performances for ADNI and AIBL were achieved for CN vs. Mild Cognitive Impairment (MCI) classification using brain volumes. The Shapley values and the feature importances showed moderate to strong correlations.
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糖尿病足溃疡是糖尿病脚对病变的常见表现,是一种作为糖尿病糖尿病的长期并发症的综合征。伴随着神经病变和血管损伤促进因缺血而收购压力损伤和组织死亡。受影响的区域易于感染,阻碍治疗进展。手头的研究调查了作为糖尿病足溃疡攻击(DFUC)2021的一部分进行的感染和缺血性的方法。有效的家庭的不同模型用于合奏。应用培训数据的扩展策略,涉及未标记的图像伪标记,并通过PIX2PIXHD广泛地产生合成图像,以应对严重的类别不平衡。由此产生的扩展训练数据集具有3.68美元的基线大小,并显示了1:3 $ 1:3 $的合成图像比率。比较了在基线和扩展训练数据集上培训的模型和合奏的性能。合成图像具有广泛的品质品种。结果表明,型号在扩展训练数据集上培训以及它们的集合受益于大型扩展。罕见课程的F1分数得到了出色的提升,而常见类别的人则不受伤害或适度促进。批判性讨论具体化益处并确定限制,建议改进。该工作得出结论,各个模型的分类性能以及集合的分类性能可以利用合成图像提升。特别是对罕见课程的表现尤其效益。
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电机控制中的一个主要问题是了解大脑计划的计划,并在面对延迟和嘈杂的刺激面前执行适当的运动。解决这种控制问题的突出框架是最佳反馈控制(OFC)。 OFC通过将嘈杂的感官刺激和使用卡尔曼滤波器或其扩展集成内部模型的预测来生成优化行为相关标准的控制操作。然而,缺乏Kalman滤波和控制的令人满意的神经模型,因为现有的提案具有以下限制:不考虑感官反馈的延迟,交替阶段的训练,以及需要了解噪声协方差矩阵,以及系统动态。此外,这些研究中的大多数考虑了卡尔曼滤波的隔离,而不是与控制联合。为了解决这些缺点,我们介绍了一种新的在线算法,它将自适应卡尔曼滤波与模型自由控制方法相结合(即,策略梯度算法)。我们在具有局部突触塑性规则的生物合理的神经网络中实现该算法。该网络执行系统识别和卡尔曼滤波,而无需多个阶段,具有不同的更新规则或噪声协方差的知识。在内部模型的帮助下,它可以使用延迟感官反馈执行状态估计。它在不需要任何信息知识的情况下了解控制政策,从而避免需要重量运输。通过这种方式,我们的OFC实施解决了在存在刺激延迟存在下生产适当的感官电动机控制所需的信用分配问题。
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The recent increase in public and academic interest in preserving biodiversity has led to the growth of the field of conservation technology. This field involves designing and constructing tools that utilize technology to aid in the conservation of wildlife. In this article, we will use case studies to demonstrate the importance of designing conservation tools with human-wildlife interaction in mind and provide a framework for creating successful tools. These case studies include a range of complexities, from simple cat collars to machine learning and game theory methodologies. Our goal is to introduce and inform current and future researchers in the field of conservation technology and provide references for educating the next generation of conservation technologists. Conservation technology not only has the potential to benefit biodiversity but also has broader impacts on fields such as sustainability and environmental protection. By using innovative technologies to address conservation challenges, we can find more effective and efficient solutions to protect and preserve our planet's resources.
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We present the interpretable meta neural ordinary differential equation (iMODE) method to rapidly learn generalizable (i.e., not parameter-specific) dynamics from trajectories of multiple dynamical systems that vary in their physical parameters. The iMODE method learns meta-knowledge, the functional variations of the force field of dynamical system instances without knowing the physical parameters, by adopting a bi-level optimization framework: an outer level capturing the common force field form among studied dynamical system instances and an inner level adapting to individual system instances. A priori physical knowledge can be conveniently embedded in the neural network architecture as inductive bias, such as conservative force field and Euclidean symmetry. With the learned meta-knowledge, iMODE can model an unseen system within seconds, and inversely reveal knowledge on the physical parameters of a system, or as a Neural Gauge to "measure" the physical parameters of an unseen system with observed trajectories. We test the validity of the iMODE method on bistable, double pendulum, Van der Pol, Slinky, and reaction-diffusion systems.
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While the brain connectivity network can inform the understanding and diagnosis of developmental dyslexia, its cause-effect relationships have not yet enough been examined. Employing electroencephalography signals and band-limited white noise stimulus at 4.8 Hz (prosodic-syllabic frequency), we measure the phase Granger causalities among channels to identify differences between dyslexic learners and controls, thereby proposing a method to calculate directional connectivity. As causal relationships run in both directions, we explore three scenarios, namely channels' activity as sources, as sinks, and in total. Our proposed method can be used for both classification and exploratory analysis. In all scenarios, we find confirmation of the established right-lateralized Theta sampling network anomaly, in line with the temporal sampling framework's assumption of oscillatory differences in the Theta and Gamma bands. Further, we show that this anomaly primarily occurs in the causal relationships of channels acting as sinks, where it is significantly more pronounced than when only total activity is observed. In the sink scenario, our classifier obtains 0.84 and 0.88 accuracy and 0.87 and 0.93 AUC for the Theta and Gamma bands, respectively.
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Variational autoencoders model high-dimensional data by positing low-dimensional latent variables that are mapped through a flexible distribution parametrized by a neural network. Unfortunately, variational autoencoders often suffer from posterior collapse: the posterior of the latent variables is equal to its prior, rendering the variational autoencoder useless as a means to produce meaningful representations. Existing approaches to posterior collapse often attribute it to the use of neural networks or optimization issues due to variational approximation. In this paper, we consider posterior collapse as a problem of latent variable non-identifiability. We prove that the posterior collapses if and only if the latent variables are non-identifiable in the generative model. This fact implies that posterior collapse is not a phenomenon specific to the use of flexible distributions or approximate inference. Rather, it can occur in classical probabilistic models even with exact inference, which we also demonstrate. Based on these results, we propose a class of latent-identifiable variational autoencoders, deep generative models which enforce identifiability without sacrificing flexibility. This model class resolves the problem of latent variable non-identifiability by leveraging bijective Brenier maps and parameterizing them with input convex neural networks, without special variational inference objectives or optimization tricks. Across synthetic and real datasets, latent-identifiable variational autoencoders outperform existing methods in mitigating posterior collapse and providing meaningful representations of the data.
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