自动驾驶(AD)相关功能代表了下一代移动机器人和专注于越来越智能,自主和互连系统的自动驾驶汽车的重要元素。根据定义,必须提供涉及使用这些功能的应用程序,并且此属性是避免灾难性事故的关键。此外,所有决策过程都必须需要低功耗,以增加电池驱动系统的寿命和自主权。这些挑战可以通过有效实施神经形态芯片上的尖峰神经网络(SNN)以及使用基于事件的摄像机而不是传统基于框架的摄像机来解决这些挑战。在本文中,我们提出了一种新的基于SNN的方法,称为Lanesnn,用于使用基于事件的相机输入来检测街道上标记的车道。我们开发了四种以低复杂性和快速响应为特征的小说SNN模型,并使用离线监督的学习规则训练它们。之后,我们将学习的SNNS模型实施并映射到Intel Loihi神经形态研究芯片上。对于损耗函数,我们基于加权二进制交叉熵(WCE)和均方误差(MSE)度量的线性组成而开发了一种新颖的方法。我们的实验结果表明,与联合(IOU)度量的最大交叉点约为0.62,功耗非常低约1W。最好的IOU是通过SNN实现实现的,该实现仅占据Loihi处理器上的36个神经可孔,同时提供低潜伏期少于8 ms识别图像,从而实现实时性能。我们网络提供的IOU措施与最先进的措施相当,但功率消耗为1W。
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在当今智能网络物理系统时代,由于它们在复杂的现实世界应用中的最新性能,深度神经网络(DNN)已无处不在。这些网络的高计算复杂性转化为增加的能源消耗,这是在资源受限系统中部署大型DNN的首要障碍。通过培训后量化实现的定点(FP)实现通常用于减少这些网络的能源消耗。但是,FP中的均匀量化间隔将数据结构的位宽度限制为大值,因为需要以足够的分辨率来表示大多数数字并避免较高的量化误差。在本文中,我们利用了关键见解,即(在大多数情况下)DNN的权重和激活主要集中在零接近零,只有少数几个具有较大的幅度。我们提出了Conlocnn,该框架是通过利用来实现节能低精度深度卷积神经网络推断的框架:(1)重量的不均匀量化,以简化复杂的乘法操作的简化; (2)激活值之间的相关性,可以在低成本的情况下以低成本进行部分补偿,而无需任何运行时开销。为了显着从不均匀的量化中受益,我们还提出了一种新颖的数据表示格式,编码低精度二进制签名数字,以压缩重量的位宽度,同时确保直接使用编码的权重来使用新颖的多重和处理 - 积累(MAC)单元设计。
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复杂的深层神经网络(例如胶囊网络(CAPSNET))以计算密集型操作为代价表现出较高的学习能力。为了使其在边缘设备上的部署,我们建议利用近似计算来设计诸如SoftMax和Squash等复杂操作的近似变体。在我们的实验中,与确切功能相比,我们评估了通过ASIC设计流实施的设计和量化capsnets的准确性的区域,功耗和关键路径延迟之间的权衡。
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Modelling and forecasting real-life human behaviour using online social media is an active endeavour of interest in politics, government, academia, and industry. Since its creation in 2006, Twitter has been proposed as a potential laboratory that could be used to gauge and predict social behaviour. During the last decade, the user base of Twitter has been growing and becoming more representative of the general population. Here we analyse this user base in the context of the 2021 Mexican Legislative Election. To do so, we use a dataset of 15 million election-related tweets in the six months preceding election day. We explore different election models that assign political preference to either the ruling parties or the opposition. We find that models using data with geographical attributes determine the results of the election with better precision and accuracy than conventional polling methods. These results demonstrate that analysis of public online data can outperform conventional polling methods, and that political analysis and general forecasting would likely benefit from incorporating such data in the immediate future. Moreover, the same Twitter dataset with geographical attributes is positively correlated with results from official census data on population and internet usage in Mexico. These findings suggest that we have reached a period in time when online activity, appropriately curated, can provide an accurate representation of offline behaviour.
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In the last years, the number of IoT devices deployed has suffered an undoubted explosion, reaching the scale of billions. However, some new cybersecurity issues have appeared together with this development. Some of these issues are the deployment of unauthorized devices, malicious code modification, malware deployment, or vulnerability exploitation. This fact has motivated the requirement for new device identification mechanisms based on behavior monitoring. Besides, these solutions have recently leveraged Machine and Deep Learning techniques due to the advances in this field and the increase in processing capabilities. In contrast, attackers do not stay stalled and have developed adversarial attacks focused on context modification and ML/DL evaluation evasion applied to IoT device identification solutions. This work explores the performance of hardware behavior-based individual device identification, how it is affected by possible context- and ML/DL-focused attacks, and how its resilience can be improved using defense techniques. In this sense, it proposes an LSTM-CNN architecture based on hardware performance behavior for individual device identification. Then, previous techniques have been compared with the proposed architecture using a hardware performance dataset collected from 45 Raspberry Pi devices running identical software. The LSTM-CNN improves previous solutions achieving a +0.96 average F1-Score and 0.8 minimum TPR for all devices. Afterward, context- and ML/DL-focused adversarial attacks were applied against the previous model to test its robustness. A temperature-based context attack was not able to disrupt the identification. However, some ML/DL state-of-the-art evasion attacks were successful. Finally, adversarial training and model distillation defense techniques are selected to improve the model resilience to evasion attacks, without degrading its performance.
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Cybercriminals are moving towards zero-day attacks affecting resource-constrained devices such as single-board computers (SBC). Assuming that perfect security is unrealistic, Moving Target Defense (MTD) is a promising approach to mitigate attacks by dynamically altering target attack surfaces. Still, selecting suitable MTD techniques for zero-day attacks is an open challenge. Reinforcement Learning (RL) could be an effective approach to optimize the MTD selection through trial and error, but the literature fails when i) evaluating the performance of RL and MTD solutions in real-world scenarios, ii) studying whether behavioral fingerprinting is suitable for representing SBC's states, and iii) calculating the consumption of resources in SBC. To improve these limitations, the work at hand proposes an online RL-based framework to learn the correct MTD mechanisms mitigating heterogeneous zero-day attacks in SBC. The framework considers behavioral fingerprinting to represent SBCs' states and RL to learn MTD techniques that mitigate each malicious state. It has been deployed on a real IoT crowdsensing scenario with a Raspberry Pi acting as a spectrum sensor. More in detail, the Raspberry Pi has been infected with different samples of command and control malware, rootkits, and ransomware to later select between four existing MTD techniques. A set of experiments demonstrated the suitability of the framework to learn proper MTD techniques mitigating all attacks (except a harmfulness rootkit) while consuming <1 MB of storage and utilizing <55% CPU and <80% RAM.
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We present a Machine Learning (ML) study case to illustrate the challenges of clinical translation for a real-time AI-empowered echocardiography system with data of ICU patients in LMICs. Such ML case study includes data preparation, curation and labelling from 2D Ultrasound videos of 31 ICU patients in LMICs and model selection, validation and deployment of three thinner neural networks to classify apical four-chamber view. Results of the ML heuristics showed the promising implementation, validation and application of thinner networks to classify 4CV with limited datasets. We conclude this work mentioning the need for (a) datasets to improve diversity of demographics, diseases, and (b) the need of further investigations of thinner models to be run and implemented in low-cost hardware to be clinically translated in the ICU in LMICs. The code and other resources to reproduce this work are available at https://github.com/vital-ultrasound/ai-assisted-echocardiography-for-low-resource-countries.
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Explainability is a vibrant research topic in the artificial intelligence community, with growing interest across methods and domains. Much has been written about the topic, yet explainability still lacks shared terminology and a framework capable of providing structural soundness to explanations. In our work, we address these issues by proposing a novel definition of explanation that is a synthesis of what can be found in the literature. We recognize that explanations are not atomic but the product of evidence stemming from the model and its input-output and the human interpretation of this evidence. Furthermore, we fit explanations into the properties of faithfulness (i.e., the explanation being a true description of the model's decision-making) and plausibility (i.e., how much the explanation looks convincing to the user). Using our proposed theoretical framework simplifies how these properties are ope rationalized and provide new insight into common explanation methods that we analyze as case studies.
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We propose a learning-based methodology to reconstruct private information held by a population of interacting agents in order to predict an exact outcome of the underlying multi-agent interaction process, here identified as a stationary action profile. We envision a scenario where an external observer, endowed with a learning procedure, is allowed to make queries and observe the agents' reactions through private action-reaction mappings, whose collective fixed point corresponds to a stationary profile. By adopting a smart query process to iteratively collect sensible data and update parametric estimates, we establish sufficient conditions to assess the asymptotic properties of the proposed learning-based methodology so that, if convergence happens, it can only be towards a stationary action profile. This fact yields two main consequences: i) learning locally-exact surrogates of the action-reaction mappings allows the external observer to succeed in its prediction task, and ii) working with assumptions so general that a stationary profile is not even guaranteed to exist, the established sufficient conditions hence act also as certificates for the existence of such a desirable profile. Extensive numerical simulations involving typical competitive multi-agent control and decision making problems illustrate the practical effectiveness of the proposed learning-based approach.
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Nature-inspired optimization Algorithms (NIOAs) are nowadays a popular choice for community detection in social networks. Community detection problem in social network is treated as optimization problem, where the objective is to either maximize the connection within the community or minimize connections between the communities. To apply NIOAs, either of the two, or both objectives are explored. Since NIOAs mostly exploit randomness in their strategies, it is necessary to analyze their performance for specific applications. In this paper, NIOAs are analyzed on the community detection problem. A direct comparison approach is followed to perform pairwise comparison of NIOAs. The performance is measured in terms of five scores designed based on prasatul matrix and also with average isolability. Three widely used real-world social networks and four NIOAs are considered for analyzing the quality of communities generated by NIOAs.
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