With the progress of sensor technology in wearables, the collection and analysis of PPG signals are gaining more interest. Using Machine Learning, the cardiac rhythm corresponding to PPG signals can be used to predict different tasks such as activity recognition, sleep stage detection, or more general health status. However, supervised learning is often limited by the amount of available labeled data, which is typically expensive to obtain. To address this problem, we propose a Self-Supervised Learning (SSL) method with a pretext task of signal reconstruction to learn an informative generalized PPG representation. The performance of the proposed SSL framework is compared with two fully supervised baselines. The results show that in a very limited label data setting (10 samples per class or less), using SSL is beneficial, and a simple classifier trained on SSL-learned representations outperforms fully supervised deep neural networks. However, the results reveal that the SSL-learned representations are too focused on encoding the subjects. Unfortunately, there is high inter-subject variability in the SSL-learned representations, which makes working with this data more challenging when labeled data is scarce. The high inter-subject variability suggests that there is still room for improvements in learning representations. In general, the results suggest that SSL may pave the way for the broader use of machine learning models on PPG data in label-scarce regimes.

The cooperation of a human pilot with an autonomous agent during flight control realizes parallel autonomy. A parallel-autonomous system acts as a guardian that significantly enhances the robustness and safety of flight operations in challenging circumstances. Here, we propose an air-guardian concept that facilitates cooperation between an artificial pilot agent and a parallel end-to-end neural control system. Our vision-based air-guardian system combines a causal continuous-depth neural network model with a cooperation layer to enable parallel autonomy between a pilot agent and a control system based on perceived differences in their attention profile. The attention profiles are obtained by computing the networks' saliency maps (feature importance) through the VisualBackProp algorithm. The guardian agent is trained via reinforcement learning in a fixed-wing aircraft simulated environment. When the attention profile of the pilot and guardian agents align, the pilot makes control decisions. If the attention map of the pilot and the guardian do not align, the air-guardian makes interventions and takes over the control of the aircraft. We show that our attention-based air-guardian system can balance the trade-off between its level of involvement in the flight and the pilot's expertise and attention. We demonstrate the effectivness of our methods in simulated flight scenarios with a fixed-wing aircraft and on a real drone platform.

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.

The field of cybersecurity is evolving fast. Experts need to be informed about past, current and - in the best case - upcoming threats, because attacks are becoming more advanced, targets bigger and systems more complex. As this cannot be addressed manually, cybersecurity experts need to rely on machine learning techniques. In the texutual domain, pre-trained language models like BERT have shown to be helpful, by providing a good baseline for further fine-tuning. However, due to the domain-knowledge and many technical terms in cybersecurity general language models might miss the gist of textual information, hence doing more harm than good. For this reason, we create a high-quality dataset and present a language model specifically tailored to the cybersecurity domain, which can serve as a basic building block for cybersecurity systems that deal with natural language. The model is compared with other models based on 15 different domain-dependent extrinsic and intrinsic tasks as well as general tasks from the SuperGLUE benchmark. On the one hand, the results of the intrinsic tasks show that our model improves the internal representation space of words compared to the other models. On the other hand, the extrinsic, domain-dependent tasks, consisting of sequence tagging and classification, show that the model is best in specific application scenarios, in contrast to the others. Furthermore, we show that our approach against catastrophic forgetting works, as the model is able to retrieve the previously trained domain-independent knowledge. The used dataset and trained model are made publicly available

Bayesian optimization (BO) is increasingly employed in critical applications such as materials design and drug discovery. An increasingly popular strategy in BO is to forgo the sole reliance on high-fidelity data and instead use an ensemble of information sources which provide inexpensive low-fidelity data. The overall premise of this strategy is to reduce the overall sampling costs by querying inexpensive low-fidelity sources whose data are correlated with high-fidelity samples. Here, we propose a multi-fidelity cost-aware BO framework that dramatically outperforms the state-of-the-art technologies in terms of efficiency, consistency, and robustness. We demonstrate the advantages of our framework on analytic and engineering problems and argue that these benefits stem from our two main contributions: (1) we develop a novel acquisition function for multi-fidelity cost-aware BO that safeguards the convergence against the biases of low-fidelity data, and (2) we tailor a newly developed emulator for multi-fidelity BO which enables us to not only simultaneously learn from an ensemble of multi-fidelity datasets, but also identify the severely biased low-fidelity sources that should be excluded from BO.

The ongoing transition from a linear (produce-use-dispose) to a circular economy poses significant challenges to current state-of-the-art information and communication technologies. In particular, the derivation of integrated, high-level views on material, process, and product streams from (real-time) data produced along value chains is challenging for several reasons. Most importantly, sufficiently rich data is often available yet not shared across company borders because of privacy concerns which make it impossible to build integrated process models that capture the interrelations between input materials, process parameters, and key performance indicators along value chains. In the current contribution, we propose a privacy-preserving, federated multivariate statistical process control (FedMSPC) framework based on Federated Principal Component Analysis (PCA) and Secure Multiparty Computation to foster the incentive for closer collaboration of stakeholders along value chains. We tested our approach on two industrial benchmark data sets - SECOM and ST-AWFD. Our empirical results demonstrate the superior fault detection capability of the proposed approach compared to standard, single-party (multiway) PCA. Furthermore, we showcase the possibility of our framework to provide privacy-preserving fault diagnosis to each data holder in the value chain to underpin the benefits of secure data sharing and federated process modeling.

线性状态空间模型（SSM）的状态过渡矩阵的适当参数化，然后是标准非线性，使他们能够从顺序数据中有效地学习表示形式，从。在本文中，我们表明，当线性液体时恒定（LTC）状态空间模型给出诸如S4之类的结构SSM时，我们可以进一步改善。 LTC神经网络是带有输入依赖性状态过渡模块的因果连续神经网络，这使他们学会在推理时适应传入的输入。我们表明，通过使用对角和S4中引入的状态过渡矩阵的对角线加低级分解以及一些简化的基于LTC的结构状态空间模型（称为Liquid-S4）实现了新的最新最先进的最先进跨序列建模任务具有长期依赖性（例如图像，文本，音频和医疗时间序列）的艺术概括，在远程竞技场基准中的平均性能为87.32％。在完整的原始语音命令识别中，数据集Liquid-S4的精度达到96.78％，与S4相比，参数计数降低了30％。性能的额外增益是液体-S4的核结构的直接结果，该结构考虑了训练和推理过程中输入序列样本的相似性。

最近的研究提出了一系列针对深度任务模型的专业优化算法。通常声称这些多任务优化（MTO）方法产生的解决方案优于仅通过优化任务损失的加权平均值而获得的解决方案。在本文中，我们对各种语言和视觉任务进行大规模实验，以检查这些主张的经验有效性。我们表明，尽管这些算法的设计和计算复杂性增加了，但MTO方法并未产生超出传统优化方法可实现的性能的任何改进。我们强调了替代策略，这些策略始终如一地提高性能概况，并指出可能导致次优效果的常见训练陷阱。最后，我们概述了可靠地评估MTO算法的性能并讨论潜在解决方案的挑战。

我们提出了Zeroeggs，这是一个神经网络框架，用于语音驱动的手势生成，以零拍出样式控制。这意味着即使在训练过程中看不见的运动样式，也只能通过一个简短的运动剪辑来控制样式。我们的模型使用一个变性框架来学习样式嵌入，从而可以通过潜在的空间操纵或样式嵌入方式的混合和缩放来修改样式。我们框架的概率性质进一步使给定输入相同的各种输出的产生，以解决手势运动的随机性质。在一系列实验中，我们首先证明了模型对新的扬声器和样式的灵活性和概括性。然后，在一项用户研究中，我们表明我们的模型在运动，语音适当性和风格刻画方面的自然性，适当性和刻画的表现优于先前的最先进技术。最后，我们释放了包括手指在内的全身手势运动的高质量数据集，语音跨越了19种不同的样式。

本文着重于基于雷达的同时定位和映射（SLAM）中的有效地标管理。必须进行地标管理，以保持相对于平台姿势估计的估计地标的一致地图。当面对从相同地标和/或动态环境的多个检测到地标可以更改的地标和/或动态环境时，此任务尤其重要。雷达数据的另一个挑战是存在错误检测。因此，我们为Radar Slam Landmark Management提出了一个简单而有效的规则解决方案。假设我们的解决方案中有几个步骤：需要检测并包括新的地标，需要识别和删除虚假地标，并且需要维护地图中注册的地标的一致性。为了说明我们的解决方案，我们在包含固定和固定地标的环境中运行扩展的Kalman Filter Slam算法。我们的仿真结果表明，即使面对虚假检测和来自同一地标的多次检测，提出的解决方案也能够可靠地管理地标。