安全关键系统通常在调试之前进行危害分析,以识别和分析操作过程中可能出现的潜在危险系统状态。当前,危害分析主要基于人类的推理,过去的经验以及清单和电子表格等简单工具。增加系统复杂性使这种方法非常合适。此外,由于高成本或身体缺陷的危险,基于测试的危害分析通常不适合。对此进行的补救措施是基于模型的危害分析方法,这些方法依赖于正式模型或模拟模型,每个模型都具有自己的好处和缺点。本文提出了一种两层方法,该方法使用正式方法与使用模拟的详细分析结合了详尽分析的好处。首先使用监督控制理论从系统的形式模型中合成了导致不安全状态的不安全行为。结果是输入到模拟的输入,在该模拟中,使用域特异性风险指标进行了详细的分析。尽管提出的方法通常适用,但本文证明了该方法对工业人类机器人协作系统的好处。
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我们提出了一种在线和数据驱动的不确定性量化方法,以实现安全的人类机器人协作应用程序的开发。安全性和系统的风险评估与测量的准确性密切相关:通常无法通过已知模型直接访问独特的参数,因此必须测量。但是,由于传感器的性能有限,甚至未知的环境干扰或人类,测量值通常会遭受不确定性的影响。在这项工作中,我们通过利用具有定量的,系统特定属性的保护措施来量化这些测量不确定性,这些措施会随时间,空间或其他状态空间维度恒定。我们方法的关键思想在于在运行时间参考保护方程式期间对传入数据的直接数据评估。特别是,我们估计违反已知的域名特定域保护特性的行为,并将其视为测量不确定性的结果。我们在人类机器人协作的背景下验证了用例验证我们的方法,从而强调了我们在现实环境下(例如在工业环境中)成功开发安全机器人系统的贡献的重要性。此外,我们还展示了如何将获得的不确定性值直接映射到任意安全限制(例如ISO 13849),该限制允许在运行时监视符合安全标准的符合性。
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我们介绍了一种新的基于模拟的方法,以识别人类机器人协作中意外的工人行为导致的危害。基于仿真的安全测试必须考虑到人类行为是变量的事实,并且可能发生人为错误。当仅模拟预期的工人行为时,严重的危险可以保持未被发现。另一方面,模拟所有可能的工人行为是计算不可行的。这提出了如何找到有趣数量的模拟运行的有趣(即潜在危险的)工作行为的问题。我们将其框架作为可能的工人行为的空间中的搜索问题。因为这个搜索空间可以得到非常复杂的,我们介绍以下措施:(1)基于工作流约束的搜索空间限制,(2)行为的优先级,基于它们偏离标称行为,(3)使用风险指标指导寻求高风险行为,这更有可能暴露危险。我们在协作工作流程中展示了涉及人工工人,机器人臂和移动机器人的协作工作流程方案的方法。
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Deep-learning of artificial neural networks (ANNs) is creating highly functional tools that are, unfortunately, as hard to interpret as their natural counterparts. While it is possible to identify functional modules in natural brains using technologies such as fMRI, we do not have at our disposal similarly robust methods for artificial neural networks. Ideally, understanding which parts of an artificial neural network perform what function might help us to address a number of vexing problems in ANN research, such as catastrophic forgetting and overfitting. Furthermore, revealing a network's modularity could improve our trust in them by making these black boxes more transparent. Here we introduce a new information-theoretic concept that proves useful in understanding and analyzing a network's functional modularity: the relay information $I_R$. The relay information measures how much information groups of neurons that participate in a particular function (modules) relay from inputs to outputs. Combined with a greedy search algorithm, relay information can be used to {\em identify} computational modules in neural networks. We also show that the functionality of modules correlates with the amount of relay information they carry.
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Cashews are grown by over 3 million smallholders in more than 40 countries worldwide as a principal source of income. As the third largest cashew producer in Africa, Benin has nearly 200,000 smallholder cashew growers contributing 15% of the country's national export earnings. However, a lack of information on where and how cashew trees grow across the country hinders decision-making that could support increased cashew production and poverty alleviation. By leveraging 2.4-m Planet Basemaps and 0.5-m aerial imagery, newly developed deep learning algorithms, and large-scale ground truth datasets, we successfully produced the first national map of cashew in Benin and characterized the expansion of cashew plantations between 2015 and 2021. In particular, we developed a SpatioTemporal Classification with Attention (STCA) model to map the distribution of cashew plantations, which can fully capture texture information from discriminative time steps during a growing season. We further developed a Clustering Augmented Self-supervised Temporal Classification (CASTC) model to distinguish high-density versus low-density cashew plantations by automatic feature extraction and optimized clustering. Results show that the STCA model has an overall accuracy of 80% and the CASTC model achieved an overall accuracy of 77.9%. We found that the cashew area in Benin has doubled from 2015 to 2021 with 60% of new plantation development coming from cropland or fallow land, while encroachment of cashew plantations into protected areas has increased by 70%. Only half of cashew plantations were high-density in 2021, suggesting high potential for intensification. Our study illustrates the power of combining high-resolution remote sensing imagery and state-of-the-art deep learning algorithms to better understand tree crops in the heterogeneous smallholder landscape.
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Local patterns play an important role in statistical physics as well as in image processing. Two-dimensional ordinal patterns were studied by Ribeiro et al. who determined permutation entropy and complexity in order to classify paintings and images of liquid crystals. Here we find that the 2 by 2 patterns of neighboring pixels come in three types. The statistics of these types, expressed by two parameters, contains the relevant information to describe and distinguish textures. The parameters are most stable and informative for isotropic structures.
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It is well known that conservative mechanical systems exhibit local oscillatory behaviours due to their elastic and gravitational potentials, which completely characterise these periodic motions together with the inertial properties of the system. The classification of these periodic behaviours and their geometric characterisation are in an on-going secular debate, which recently led to the so-called eigenmanifold theory. The eigenmanifold characterises nonlinear oscillations as a generalisation of linear eigenspaces. With the motivation of performing periodic tasks efficiently, we use tools coming from this theory to construct an optimization problem aimed at inducing desired closed-loop oscillations through a state feedback law. We solve the constructed optimization problem via gradient-descent methods involving neural networks. Extensive simulations show the validity of the approach.
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Artificial intelligence(AI) systems based on deep neural networks (DNNs) and machine learning (ML) algorithms are increasingly used to solve critical problems in bioinformatics, biomedical informatics, and precision medicine. However, complex DNN or ML models that are unavoidably opaque and perceived as black-box methods, may not be able to explain why and how they make certain decisions. Such black-box models are difficult to comprehend not only for targeted users and decision-makers but also for AI developers. Besides, in sensitive areas like healthcare, explainability and accountability are not only desirable properties of AI but also legal requirements -- especially when AI may have significant impacts on human lives. Explainable artificial intelligence (XAI) is an emerging field that aims to mitigate the opaqueness of black-box models and make it possible to interpret how AI systems make their decisions with transparency. An interpretable ML model can explain how it makes predictions and which factors affect the model's outcomes. The majority of state-of-the-art interpretable ML methods have been developed in a domain-agnostic way and originate from computer vision, automated reasoning, or even statistics. Many of these methods cannot be directly applied to bioinformatics problems, without prior customization, extension, and domain adoption. In this paper, we discuss the importance of explainability with a focus on bioinformatics. We analyse and comprehensively overview of model-specific and model-agnostic interpretable ML methods and tools. Via several case studies covering bioimaging, cancer genomics, and biomedical text mining, we show how bioinformatics research could benefit from XAI methods and how they could help improve decision fairness.
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Generic Object Tracking (GOT) is the problem of tracking target objects, specified by bounding boxes in the first frame of a video. While the task has received much attention in the last decades, researchers have almost exclusively focused on the single object setting. Multi-object GOT benefits from a wider applicability, rendering it more attractive in real-world applications. We attribute the lack of research interest into this problem to the absence of suitable benchmarks. In this work, we introduce a new large-scale GOT benchmark, LaGOT, containing multiple annotated target objects per sequence. Our benchmark allows researchers to tackle key remaining challenges in GOT, aiming to increase robustness and reduce computation through joint tracking of multiple objects simultaneously. Furthermore, we propose a Transformer-based GOT tracker TaMOS capable of joint processing of multiple objects through shared computation. TaMOs achieves a 4x faster run-time in case of 10 concurrent objects compared to tracking each object independently and outperforms existing single object trackers on our new benchmark. Finally, TaMOs achieves highly competitive results on single-object GOT datasets, setting a new state-of-the-art on TrackingNet with a success rate AUC of 84.4%. Our benchmark, code, and trained models will be made publicly available.
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In recent years the applications of machine learning models have increased rapidly, due to the large amount of available data and technological progress.While some domains like web analysis can benefit from this with only minor restrictions, other fields like in medicine with patient data are strongerregulated. In particular \emph{data privacy} plays an important role as recently highlighted by the trustworthy AI initiative of the EU or general privacy regulations in legislation. Another major challenge is, that the required training \emph{data is} often \emph{distributed} in terms of features or samples and unavailable for classicalbatch learning approaches. In 2016 Google came up with a framework, called \emph{Federated Learning} to solve both of these problems. We provide a brief overview on existing Methods and Applications in the field of vertical and horizontal \emph{Federated Learning}, as well as \emph{Fderated Transfer Learning}.
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