由于可以自主使用的广泛应用,无人驾驶汽车(UAV)一直脱颖而出。但是,他们需要智能系统,能够提供对执行多个任务的看法的更多了解。在复杂的环境中,它们变得更具挑战性,因为有必要感知环境并在环境不确定性下采取行动以做出决定。在这种情况下,使用主动感知的系统可以通过在发生位移时通过识别目标来寻求最佳下一个观点来提高性能。这项工作旨在通过解决跟踪和识别水面结构以执行动态着陆的问题来为无人机的积极感知做出贡献。我们表明,使用经典图像处理技术和简单的深度强化学习(DEEP-RL)代理能够感知环境并处理不确定性的情况,而无需使用复杂的卷积神经网络(CNN)或对比度学习(CL),我们的系统能够感知环境并处理不确定性(CL),我们的系统能够感知环境并处理不确定性。 。
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先前的工作表明,深-RL可以应用于无地图导航,包括混合无人驾驶空中水下车辆(Huauvs)的中等过渡。本文介绍了基于最先进的演员批评算法的新方法,以解决Huauv的导航和中型过渡问题。我们表明,具有复发性神经网络的双重评论家Deep-RL可以使用仅范围数据和相对定位来改善Huauvs的导航性能。我们的深-RL方法通过通过不同的模拟场景对学习的扎实概括,实现了更好的导航和过渡能力,表现优于先前的方法。
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深钢筋学习中的确定性和随机技术已成为改善运动控制和各种机器人的决策任务的有前途的解决方案。先前的工作表明,这些深-RL算法通常可以应用于一般的移动机器人的无MAP导航。但是,他们倾向于使用简单的传感策略,因为已经证明它们在高维状态空间(例如基于图像的传感的空间)方面的性能不佳。本文在执行移动机器人无地图导航的任务时,对两种深-RL技术 - 深确定性政策梯度(DDPG)和软参与者(SAC)进行了比较分析。我们的目标是通过展示神经网络体系结构如何影响学习本身的贡献,并根据每种方法的航空移动机器人导航的时间和距离提出定量结果。总体而言,我们对六个不同体系结构的分析强调了随机方法(SAC)更好地使用更深的体系结构,而恰恰相反发生在确定性方法(DDPG)中。
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在水下活动期间获得的图像遭受了水的环境特性,例如浊度和衰减。这些现象会导致颜色失真,模糊和对比度减少。另外,不规则的环境光分布会导致色道不平衡和具有高强度像素的区域。最近的作品与水下图像增强有关,并基于深度学习方法,解决了缺乏生成合成基地真相的配对数据集。在本文中,我们提出了一种基于深度学习的水下图像增强的自我监督学习方法,不需要配对的数据集。提出的方法估计了水下图像中存在的降解。此外,自动编码器重建此图像,并使用估计的降解信息降解其输出图像。因此,该策略在训练阶段的损失函数中用降级版本代替了输出图像。此过程\ textIt {Misleads}学会补偿其他降解的神经网络。结果,重建的图像是输入图像的增强版本。此外,该算法还提出了一个注意模块,以减少通过颜色通道不平衡和异常区域在增强图像中产生的高强度区域。此外,提出的方法不需要基本真实。此外,仅使用真实的水下图像来训练神经网络,结果表明该方法在颜色保存,颜色铸造降低和对比度改进方面的有效性。
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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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The ability to convert reciprocating, i.e., alternating, actuation into rotary motion using linkages is hindered fundamentally by their poor torque transmission capability around kinematic singularity configurations. Here, we harness the elastic potential energy of a linear spring attached to the coupler link of four-bar mechanisms to manipulate force transmission around the kinematic singularities. We developed a theoretical model to explore the parameter space for proper force transmission in slider-crank and rocker-crank four-bar kinematics. Finally, we verified the proposed model and methodology by building and testing a macro-scale prototype of a slider-crank mechanism. We expect this approach to enable the development of small-scale rotary engines and robotic devices with closed kinematic chains dealing with serial kinematic singularities, such as linkages and parallel manipulators.
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Image classification with small datasets has been an active research area in the recent past. However, as research in this scope is still in its infancy, two key ingredients are missing for ensuring reliable and truthful progress: a systematic and extensive overview of the state of the art, and a common benchmark to allow for objective comparisons between published methods. This article addresses both issues. First, we systematically organize and connect past studies to consolidate a community that is currently fragmented and scattered. Second, we propose a common benchmark that allows for an objective comparison of approaches. It consists of five datasets spanning various domains (e.g., natural images, medical imagery, satellite data) and data types (RGB, grayscale, multispectral). We use this benchmark to re-evaluate the standard cross-entropy baseline and ten existing methods published between 2017 and 2021 at renowned venues. Surprisingly, we find that thorough hyper-parameter tuning on held-out validation data results in a highly competitive baseline and highlights a stunted growth of performance over the years. Indeed, only a single specialized method dating back to 2019 clearly wins our benchmark and outperforms the baseline classifier.
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The availability of frequent and cost-free satellite images is in growing demand in the research world. Such satellite constellations as Landsat 8 and Sentinel-2 provide a massive amount of valuable data daily. However, the discrepancy in the sensors' characteristics of these satellites makes it senseless to use a segmentation model trained on either dataset and applied to another, which is why domain adaptation techniques have recently become an active research area in remote sensing. In this paper, an experiment of domain adaptation through style-transferring is conducted using the HRSemI2I model to narrow the sensor discrepancy between Landsat 8 and Sentinel-2. This paper's main contribution is analyzing the expediency of that approach by comparing the results of segmentation using domain-adapted images with those without adaptation. The HRSemI2I model, adjusted to work with 6-band imagery, shows significant intersection-over-union performance improvement for both mean and per class metrics. A second contribution is providing different schemes of generalization between two label schemes - NALCMS 2015 and CORINE. The first scheme is standardization through higher-level land cover classes, and the second is through harmonization validation in the field.
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The intersection of ground reaction forces in a small, point-like area above the center of mass has been observed in computer simulation models and human walking experiments. This intersection point is often called a virtual pivot point (VPP). With the VPP observed so ubiquitously, it is commonly assumed to provide postural stability for bipedal walking. In this study, we challenge this assumption by questioning if walking without a VPP is possible. Deriving gaits with a neuromuscular reflex model through multi-stage optimization, we found stable walking patterns that show no signs of the VPP-typical intersection of ground reaction forces. We, therefore, conclude that a VPP is not necessary for upright, stable walking. The non-VPP gaits found are stable and successfully rejected step-down perturbations, which indicates that a VPP is not primarily responsible for locomotion robustness or postural stability. However, a collision-based analysis indicates that non-VPP gaits increased the potential for collisions between the vectors of the center of mass velocity and ground reaction forces during walking, suggesting an increased mechanical cost of transport. Although our computer simulation results have yet to be confirmed through experimental studies, they already strongly challenge the existing explanation of the VPP's function and provide an alternative explanation.
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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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