我们介绍了一种新的算法,基于回归的监督学习(RSL),用于每个实例神经网络(NN)为经典计划问题定义的启发式功能。RSL使用回归来选择与目标不同距离的相关状态集。然后,RSL制定了一个监督的学习问题,以获取定义NN启发式的参数,并使用标记为目标状态的精确或估计距离的选定状态。我们的实验研究表明,RSL在覆盖范围内优于先前的经典计划NN启发式功能,同时需要减少两个数量级的训练时间。
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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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基于脑部的事件的神经形态处理系统已成为一种有前途的技术,尤其是生物医学电路和系统。但是,神经网络的神经形态和生物学实现都具有关键的能量和记忆约束。为了最大程度地减少在多核神经形态处理器中的内存资源的使用,我们提出了一种受生物神经网络启发的网络设计方法。我们使用这种方法来设计针对小世界网络优化的新路由方案,同时介绍了一种硬件感知的放置算法,该算法优化了针对小型世界网络模型的资源分配。我们使用规范的小世界网络验证算法,并为其他网络提供初步结果
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在无人车的领域,自主机器人群体承诺将提高效率和集体自主权。这些群体将来将如何运作,以及尚未充分定义这些沟通要求和运营界限。与11位专业的无人车运营商和设计师进行了研讨会,目的是确定用于开发和测试机器人群的用例。专家定义了三个方案,然后编译以生产一个用例,概述与高度自主群合作时的情况,目标,代理,通信要求和操作阶段。我们的编译用例均适用于研究人员,设计师和制造商,以测试和量身定制其设计管道,以适应人类互动的一些关键问题。应用程序的示例包括告知模拟开发,构成进一步设计研讨会的基础,并确定人类运营商与群体之间可能出现的信任问题。
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基于深度学习的技术实现最新的技术会导致广泛的图像重建任务,例如压缩传感。这些方法几乎总是具有超参数,例如在优化损耗函数中平衡不同项的权重系数。典型的方法是训练模型,以通过某些经验或理论理由确定的超参数设置。因此,在推理时,模型只能计算与预定的超参数值相对应的重建。在这项工作中,我们提出了一种基于超网络的方法,称为HyperRecon,以训练不可知论到超参数设置的重建模型。在推理时,HyperRecon可以有效地产生不同的重建,每个重建都对应于不同的高参数值。在此框架中,用户有权根据自己的判断选择最有用的输出。我们使用两个大规模和公共可用的MRI数据集演示了压缩感测,超分辨率和去索任务的方法。我们的代码可在https://github.com/alanqrwang/hyhyperrecon上找到。
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人工智能(AI)为简化Covid-19诊断提供了有前景的替代。然而,涉及周围的安全和可信度的担忧阻碍了大规模代表性的医学数据,对临床实践中训练广泛的模型造成了相当大的挑战。为了解决这个问题,我们启动了统一的CT-Covid AI诊断计划(UCADI),其中AI模型可以在没有数据共享的联合学习框架(FL)下在每个主机机构下分发和独立地在没有数据共享的情况下在每个主机机构上执行。在这里,我们认为我们的FL模型通过大的产量(中国测试敏感性/特异性:0.973 / 0.951,英国:0.730 / 0.942),与专业放射科医师的面板实现可比性表现。我们进一步评估了持有的模型(从另外两家医院收集,留出FL)和异构(用造影材料获取)数据,提供了模型所做的决策的视觉解释,并分析了模型之间的权衡联邦培训过程中的性能和沟通成本。我们的研究基于来自位于中国和英国的23家医院的3,336名患者的9,573次胸部计算断层扫描扫描(CTS)。统称,我们的工作提出了利用联邦学习的潜在保留了数字健康的前景。
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We present VoxelMorph, a fast learning-based framework for deformable, pairwise medical image registration. Traditional registration methods optimize an objective function for each pair of images, which can be time-consuming for large datasets or rich deformation models. In contrast to this approach, and building on recent learning-based methods, we formulate registration as a function that maps an input image pair to a deformation field that aligns these images. We parameterize the function via a convolutional neural network (CNN), and optimize the parameters of the neural network on a set of images. Given a new pair of scans, VoxelMorph rapidly computes a deformation field by directly evaluating the function. In this work, we explore two different training strategies. In the first (unsupervised) setting, we train the model to maximize standard image matching objective functions that are based on the image intensities. In the second setting, we leverage auxiliary segmentations available in the training data. We demonstrate that the unsupervised model's accuracy is comparable to state-of-the-art methods, while operating orders of magnitude faster. We also show that VoxelMorph trained with auxiliary data improves registration accuracy at test time, and evaluate the effect of training set size on registration. Our method promises to speed up medical image analysis and processing pipelines, while facilitating novel directions in learning-based registration and its applications. Our code is freely available at http://voxelmorph.csail.mit.edu.
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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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A Digital Twin (DT) is a simulation of a physical system that provides information to make decisions that add economic, social or commercial value. The behaviour of a physical system changes over time, a DT must therefore be continually updated with data from the physical systems to reflect its changing behaviour. For resource-constrained systems, updating a DT is non-trivial because of challenges such as on-board learning and the off-board data transfer. This paper presents a framework for updating data-driven DTs of resource-constrained systems geared towards system health monitoring. The proposed solution consists of: (1) an on-board system running a light-weight DT allowing the prioritisation and parsimonious transfer of data generated by the physical system; and (2) off-board robust updating of the DT and detection of anomalous behaviours. Two case studies are considered using a production gas turbine engine system to demonstrate the digital representation accuracy for real-world, time-varying physical systems.
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We consider infinite horizon Markov decision processes (MDPs) with fast-slow structure, meaning that certain parts of the state space move "fast" (and in a sense, are more influential) while other parts transition more "slowly." Such structure is common in real-world problems where sequential decisions need to be made at high frequencies, yet information that varies at a slower timescale also influences the optimal policy. Examples include: (1) service allocation for a multi-class queue with (slowly varying) stochastic costs, (2) a restless multi-armed bandit with an environmental state, and (3) energy demand response, where both day-ahead and real-time prices play a role in the firm's revenue. Models that fully capture these problems often result in MDPs with large state spaces and large effective time horizons (due to frequent decisions), rendering them computationally intractable. We propose an approximate dynamic programming algorithmic framework based on the idea of "freezing" the slow states, solving a set of simpler finite-horizon MDPs (the lower-level MDPs), and applying value iteration (VI) to an auxiliary MDP that transitions on a slower timescale (the upper-level MDP). We also extend the technique to a function approximation setting, where a feature-based linear architecture is used. On the theoretical side, we analyze the regret incurred by each variant of our frozen-state approach. Finally, we give empirical evidence that the frozen-state approach generates effective policies using just a fraction of the computational cost, while illustrating that simply omitting slow states from the decision modeling is often not a viable heuristic.
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