马尔可夫决策过程(MDP)是在顺序决策中常用的正式模型。 MDP捕获了可能出现的随机性,例如,通过过渡函数中的概率从不精确的执行器中捕获。但是,在数据驱动的应用程序中,从(有限)数据中得出精确的概率引入了可能导致意外或不良结果的统计错误。不确定的MDP(UMDP)不需要精确的概率,而是在过渡中使用所谓的不确定性集,占此类有限的数据。正式验证社区中的工具有效地计算了强大的政策,这些政策在不确定性集中最坏的情况下,可以证明遵守正式规格,例如安全限制。我们不断地以强大的学习方法与将专用的贝叶斯推理方案与强大策略的计算结合在一起的任何时间学习方法中不断学习MDP的过渡概率。特别是,我们的方法(1)将概率近似为间隔,(2)适应可能与中间模型不一致的新数据,并且可以随时停止(3),以在UMDP上计算强大的策略,以忠实地捕获稳健的策略到目前为止的数据。我们展示了我们的方法的有效性,并将其与在几个基准的实验评估中对UMDP计算出的UMDP进行了比较。
translated by 谷歌翻译
大型语言模型已被证明可以使用少量学习来实现各种自然语言任务的出色表现,这大大减少了将模型调整到特定应用程序所需的特定任务培训示例的数量。为了进一步了解量表对少量学习的影响,我们培训了一个5400亿个参数,密集激活的变压器语言模型,我们称之为“途径”语言模型棕榈。我们使用Pathways在6144 TPU V4芯片上训练了Palm,这是一种新的ML系统,可在多个TPU POD上进行高效的训练。我们通过在数百种语言理解和产生基准的基准方面实现最先进的学习结果来证明扩展的持续好处。在这些任务中,Palm 540B实现了突破性的表现,在一系列多步推理任务上表现出色,超过了最新的最新表现,并且在最近发布的Big Benchmark上表现优于平均人类表现。大量的大型基础任务显示出与模型量表的不连续改进,这意味着当我们扩展到最大模型时,性能急剧增加。 Palm在多语言任务和源代码生成方面也具有很强的功能,我们在各种基准测试中证明了这一点。我们还提供了有关偏见和毒性的全面分析,并研究了训练数据记忆的程度,相对于模型量表。最后,我们讨论与大语言模型有关的道德考虑,并讨论潜在的缓解策略。
translated by 谷歌翻译
人工智能的神经符号方法将神经网络与经典的象征技术结合起来,正在逐渐突出,需要正式的方法来推理其正确性。我们提出了一种新型的建模形式主义,称为神经符号并发随机游戏(NS-CSGS),该游戏包括在共享的连续状态环境中相互作用的概率有限状态的概率有限状态,通过以神经网络实现的感知机制观察到。由于环境状态空间是连续的,因此我们专注于具有Borel状态空间的NS-CSG类。我们考虑了零和折扣累积奖励的问题,并证明了在Borel可测量性和对模型组件的分段限制下NS-CSG的价值的存在。从算法的角度来看,计算CSG的值和最佳策略的现有方法集中在有限状态空间上。我们首次介绍可实施的价值迭代和政策迭代算法,以求解一类无数状态空间CSG,即NS-CSG,并证明其收敛性。我们的方法通过利用基础游戏结构,然后制定NS-CSG的价值函数和策略的分段线性或恒定表示。我们通过将价值迭代的原型实施应用于动态的停车案例研究来说明我们的方法。
translated by 谷歌翻译
深度加强学习是一种越来越流行的技术,用于综合政策以控制代理商与其环境的互动。正式验证此类策略是否正确并安全执行,并且安全地执行兴趣。通过建立现有工作来验证深神经网络和连续状态动态系统的现有工作,已经在这方面取得了进展。在本文中,我们解决了验证深度加强学习的概率政策的问题,这些政策用于例如解决对抗性环境,破坏对称和管理权衡。我们提出了一种基于间隔马尔可夫决策过程的抽象方法,它会产生策略的执行上的概率保证,并使用抽象解释,混合整数线性编程,基于熵的细化和概率模型检查来构建和解决这些模型的概率保证。我们实施了我们的方法,并说明了它在选择加强学习基准的效力。
translated by 谷歌翻译
在安全关键设置中运行的自治系统的控制器必须考虑随机扰动。这种干扰通常被建模为过程噪声,并且常见的假设是底层分布是已知的和/或高斯的。然而,在实践中,这些假设可能是不现实的并且可以导致真正噪声分布的近似值。我们提出了一种新的规划方法,不依赖于噪声分布的任何明确表示。特别是,我们解决了计算控制器的控制器,该控制器提供了安全地到达目标的概率保证。首先,我们将连续系统摘要进入一个离散状态模型,通过状态之间的概率转换捕获噪声。作为关键贡献,我们根据噪声的有限数量的样本来调整这些过渡概率的方案方法中的工具。我们在所谓的间隔马尔可夫决策过程(IMDP)的转换概率间隔中捕获这些界限。该IMDP在过渡概率中的不确定性稳健,并且可以通过样本的数量来控制概率间隔的紧张性。我们使用最先进的验证技术在IMDP上提供保证,并计算这些保证对自主系统的控制器。即使IMDP有数百万个州或过渡,也表明了我们方法的实际适用性。
translated by 谷歌翻译
In this paper, we propose a novel technique, namely INVALIDATOR, to automatically assess the correctness of APR-generated patches via semantic and syntactic reasoning. INVALIDATOR reasons about program semantic via program invariants while it also captures program syntax via language semantic learned from large code corpus using the pre-trained language model. Given a buggy program and the developer-patched program, INVALIDATOR infers likely invariants on both programs. Then, INVALIDATOR determines that a APR-generated patch overfits if: (1) it violates correct specifications or (2) maintains errors behaviors of the original buggy program. In case our approach fails to determine an overfitting patch based on invariants, INVALIDATOR utilizes a trained model from labeled patches to assess patch correctness based on program syntax. The benefit of INVALIDATOR is three-fold. First, INVALIDATOR is able to leverage both semantic and syntactic reasoning to enhance its discriminant capability. Second, INVALIDATOR does not require new test cases to be generated but instead only relies on the current test suite and uses invariant inference to generalize the behaviors of a program. Third, INVALIDATOR is fully automated. We have conducted our experiments on a dataset of 885 patches generated on real-world programs in Defects4J. Experiment results show that INVALIDATOR correctly classified 79% overfitting patches, accounting for 23% more overfitting patches being detected by the best baseline. INVALIDATOR also substantially outperforms the best baselines by 14% and 19% in terms of Accuracy and F-Measure, respectively.
translated by 谷歌翻译
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.
translated by 谷歌翻译
Variational autoencoders model high-dimensional data by positing low-dimensional latent variables that are mapped through a flexible distribution parametrized by a neural network. Unfortunately, variational autoencoders often suffer from posterior collapse: the posterior of the latent variables is equal to its prior, rendering the variational autoencoder useless as a means to produce meaningful representations. Existing approaches to posterior collapse often attribute it to the use of neural networks or optimization issues due to variational approximation. In this paper, we consider posterior collapse as a problem of latent variable non-identifiability. We prove that the posterior collapses if and only if the latent variables are non-identifiable in the generative model. This fact implies that posterior collapse is not a phenomenon specific to the use of flexible distributions or approximate inference. Rather, it can occur in classical probabilistic models even with exact inference, which we also demonstrate. Based on these results, we propose a class of latent-identifiable variational autoencoders, deep generative models which enforce identifiability without sacrificing flexibility. This model class resolves the problem of latent variable non-identifiability by leveraging bijective Brenier maps and parameterizing them with input convex neural networks, without special variational inference objectives or optimization tricks. Across synthetic and real datasets, latent-identifiable variational autoencoders outperform existing methods in mitigating posterior collapse and providing meaningful representations of the data.
translated by 谷歌翻译
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.
translated by 谷歌翻译
Coronary Computed Tomography Angiography (CCTA) provides information on the presence, extent, and severity of obstructive coronary artery disease. Large-scale clinical studies analyzing CCTA-derived metrics typically require ground-truth validation in the form of high-fidelity 3D intravascular imaging. However, manual rigid alignment of intravascular images to corresponding CCTA images is both time consuming and user-dependent. Moreover, intravascular modalities suffer from several non-rigid motion-induced distortions arising from distortions in the imaging catheter path. To address these issues, we here present a semi-automatic segmentation-based framework for both rigid and non-rigid matching of intravascular images to CCTA images. We formulate the problem in terms of finding the optimal \emph{virtual catheter path} that samples the CCTA data to recapitulate the coronary artery morphology found in the intravascular image. We validate our co-registration framework on a cohort of $n=40$ patients using bifurcation landmarks as ground truth for longitudinal and rotational registration. Our results indicate that our non-rigid registration significantly outperforms other co-registration approaches for luminal bifurcation alignment in both longitudinal (mean mismatch: 3.3 frames) and rotational directions (mean mismatch: 28.6 degrees). By providing a differentiable framework for automatic multi-modal intravascular data fusion, our developed co-registration modules significantly reduces the manual effort required to conduct large-scale multi-modal clinical studies while also providing a solid foundation for the development of machine learning-based co-registration approaches.
translated by 谷歌翻译