Magnetic resonance (MR) and computer tomography (CT) images are two typical types of medical images that provide mutually-complementary information for accurate clinical diagnosis and treatment. However, obtaining both images may be limited due to some considerations such as cost, radiation dose and modality missing. Recently, medical image synthesis has aroused gaining research interest to cope with this limitation. In this paper, we propose a bidirectional learning model, denoted as dual contrast cycleGAN (DC-cycleGAN), to synthesize medical images from unpaired data. Specifically, a dual contrast loss is introduced into the discriminators to indirectly build constraints between real source and synthetic images by taking advantage of samples from the source domain as negative samples and enforce the synthetic images to fall far away from the source domain. In addition, cross-entropy and structural similarity index (SSIM) are integrated into the DC-cycleGAN in order to consider both the luminance and structure of samples when synthesizing images. The experimental results indicate that DC-cycleGAN is able to produce promising results as compared with other cycleGAN-based medical image synthesis methods such as cycleGAN, RegGAN, DualGAN, and NiceGAN. The code will be available at https://github.com/JiayuanWang-JW/DC-cycleGAN.
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异常检测是指识别偏离正常模式的观察,这是各个领域的活跃研究区域。最近,数据量表越来越多,复杂性和维度将传统的表示和基于统计的异常检测方法变得具有挑战性。在本文中,我们利用了高光谱图像异常检测的生成模型。 GIST是模拟正常数据的分布,而分布外样品可以被视为异常值。首先,研究了基于变分的基于异常的检测方法。理论上和经验地发现它们由于距离强烈的概念($ F $ -divergence)作为正则化而不稳定。其次,本文介绍了切片的Wasserstein距离,与F分歧相比,这是一种较弱的分布措施。然而,随机切片的数量难以估计真正的距离。最后,我们提出了一个投影的切片Wasserstein(PSW)基于AutoEncoder的异常筛选方法。特别是,我们利用计算友好的特征分解方法来找到切片高维数据的主成分。此外,我们所提出的距离可以用闭合形式计算,即使是先前的分布也不是高斯。在各种现实世界高光谱异常检测基准上进行的综合实验证明了我们提出的方法的卓越性能。
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广义零射击学习(GZSL)旨在培训一个模型,以在某些输出类别在监督学习过程中未知的情况下对数据样本进行分类。为了解决这一具有挑战性的任务,GZSL利用可见的(源)和看不见的(目标)类的语义信息来弥合所见类和看不见的类之间的差距。自引入以来,已经制定了许多GZSL模型。在这篇评论论文中,我们介绍了有关GZSL的全面评论。首先,我们提供了GZSL的概述,包括问题和挑战。然后,我们为GZSL方法介绍了分层分类,并讨论了每个类别中的代表性方法。此外,我们讨论了GZSL的可用基准数据集和应用程序,以及有关研究差距和未来研究方向的讨论。
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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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语言模型既展示了定量的改进,又展示了新的定性功能,随着规模的增加。尽管它们具有潜在的变革性影响,但这些新能力的特征却很差。为了为未来的研究提供信息,为破坏性的新模型能力做准备,并改善社会有害的效果,至关重要的是,我们必须了解目前和近乎未来的能力和语言模型的局限性。为了应对这一挑战,我们介绍了超越模仿游戏基准(Big Bench)。 Big Bench目前由204个任务组成,由132家机构的442位作者贡献。任务主题是多样的,从语言学,儿童发展,数学,常识性推理,生物学,物理学,社会偏见,软件开发等等。 Big-Bench专注于被认为超出当前语言模型的功能的任务。我们评估了OpenAI的GPT型号,Google内部密集变压器体系结构和大型基础上的开关稀疏变压器的行为,跨越了数百万到数十亿个参数。此外,一个人类专家评估者团队执行了所有任务,以提供强大的基准。研究结果包括:模型性能和校准都随规模改善,但绝对的术语(以及与评估者的性能相比);在模型类中的性能非常相似,尽管带有稀疏性。逐渐和预测的任务通常涉及大量知识或记忆成分,而在临界规模上表现出“突破性”行为的任务通常涉及多个步骤或组成部分或脆性指标;社交偏见通常会随着含糊不清的环境而随着规模而增加,但这可以通过提示来改善。
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域适应(DA)最近在医学影像社区提出了强烈的兴趣。虽然已经提出了大量DA技术进行了用于图像分割,但大多数这些技术已经在私有数据集或小公共可用数据集上验证。此外,这些数据集主要解决了单级问题。为了解决这些限制,与第24届医学图像计算和计算机辅助干预(Miccai 2021)结合第24届国际会议组织交叉模态域适应(Crossmoda)挑战。 Crossmoda是无监督跨型号DA的第一个大型和多级基准。挑战的目标是分割参与前庭施瓦新瘤(VS)的后续和治疗规划的两个关键脑结构:VS和Cochleas。目前,使用对比度增强的T1(CET1)MRI进行VS患者的诊断和监测。然而,使用诸如高分辨率T2(HRT2)MRI的非对比度序列越来越感兴趣。因此,我们创建了一个无人监督的跨模型分段基准。训练集提供注释CET1(n = 105)和未配对的非注释的HRT2(n = 105)。目的是在测试集中提供的HRT2上自动对HRT2进行单侧VS和双侧耳蜗分割(n = 137)。共有16支球队提交了评估阶段的算法。顶级履行团队达成的表现水平非常高(最佳中位数骰子 - vs:88.4%; Cochleas:85.7%)并接近完全监督(中位数骰子 - vs:92.5%;耳蜗:87.7%)。所有顶级执行方法都使用图像到图像转换方法将源域图像转换为伪目标域图像。然后使用这些生成的图像和为源图像提供的手动注释进行培训分割网络。
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Large language models (LLMs) have shown impressive results across a variety of tasks while requiring little or no direct supervision. Further, there is mounting evidence that LLMs may have potential in information-seeking scenarios. We believe the ability of an LLM to attribute the text that it generates is likely to be crucial for both system developers and users in this setting. We propose and study Attributed QA as a key first step in the development of attributed LLMs. We develop a reproducable evaluation framework for the task, using human annotations as a gold standard and a correlated automatic metric that we show is suitable for development settings. We describe and benchmark a broad set of architectures for the task. Our contributions give some concrete answers to two key questions (How to measure attribution?, and How well do current state-of-the-art methods perform on attribution?), and give some hints as to how to address a third key question (How to build LLMs with attribution?).
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We introduce a new benchmark dataset, Placenta, for node classification in an underexplored domain: predicting microanatomical tissue structures from cell graphs in placenta histology whole slide images. This problem is uniquely challenging for graph learning for a few reasons. Cell graphs are large (>1 million nodes per image), node features are varied (64-dimensions of 11 types of cells), class labels are imbalanced (9 classes ranging from 0.21% of the data to 40.0%), and cellular communities cluster into heterogeneously distributed tissues of widely varying sizes (from 11 nodes to 44,671 nodes for a single structure). Here, we release a dataset consisting of two cell graphs from two placenta histology images totalling 2,395,747 nodes, 799,745 of which have ground truth labels. We present inductive benchmark results for 7 scalable models and show how the unique qualities of cell graphs can help drive the development of novel graph neural network architectures.
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Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.
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This paper presents a methodology for combining programming and mathematics to optimize elevator wait times. Based on simulated user data generated according to the canonical three-peak model of elevator traffic, we first develop a naive model from an intuitive understanding of the logic behind elevators. We take into consideration a general array of features including capacity, acceleration, and maximum wait time thresholds to adequately model realistic circumstances. Using the same evaluation framework, we proceed to develop a Deep Q Learning model in an attempt to match the hard-coded naive approach for elevator control. Throughout the majority of the paper, we work under a Markov Decision Process (MDP) schema, but later explore how the assumption fails to characterize the highly stochastic overall Elevator Group Control System (EGCS).
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