目的:大大缩短定量3D化学交换饱和转移(CEST)和半固体磁化转移(MT)成像所需的采集时间,并允许快速化学交换参数图重建。方法:三维CEST和MT磁共振指纹(MRF)数据集的L-精氨酸幻象,全脑,全脑和小腿肌肉的健康志愿者,癌症患者和心脏病患者是使用3T临床扫描仪在3T不同的位点使用3T临床扫描仪获得的3种不同的扫描仪模型和线圈。然后,设计和训练了一个生成的对抗网络监督框架(GAN-CEST),以学习从减少的输入数据空间到定量交换参数空间的映射,同时保留感知和定量内容。结果:GAN-CEST 3D采集时间为42-52秒,比CEST-MRF短70%。整个大脑的定量重建需要0.8秒。在地面真相和基于GAN的L-精氨酸浓度和pH值之间观察到了极好的一致性(Pearson的R> 0.97,NRMSE <1.5%)。来自脑肿瘤受试者的gan-cest图像产生的半固体量分数和汇率NRMSE为3.8 $ \ pm $ 1.3%和4.6 $ \ pm $ 1.3%,SSIM和96.3 $ \ pm $ \ pm $ 1.6%和95.0 $ \ pm $ 2.4%。半固体交换参数的NRMSE <7%和SSIM> 94%的小腿肌肉交换参数的映射。与MRF相比,在具有较大敏感性伪像的区域中,Gan-Cest表现出改善的性能和噪声降低。结论:Gan-Cest可以大大减少定量半固体MT/CEST映射的获取时间,同时即使在训练过程中无法使用的病理和扫描仪模型时,也可以保持性能。
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深度学习(DL)模型为各种医学成像基准挑战提供了最先进的性能,包括脑肿瘤细分(BRATS)挑战。然而,局灶性病理多隔室分割(例如,肿瘤和病变子区)的任务特别具有挑战性,并且潜在的错误阻碍DL模型转化为临床工作流程。量化不确定形式的DL模型预测的可靠性,可以实现最不确定的地区的临床审查,从而建立信任并铺平临床翻译。最近,已经引入了许多不确定性估计方法,用于DL医学图像分割任务。开发指标评估和比较不确定性措施的表现将有助于最终用户制定更明智的决策。在本研究中,我们探索并评估在Brats 2019-2020任务期间开发的公制,以对不确定量化量化(Qu-Brats),并旨在评估和排列脑肿瘤多隔室分割的不确定性估计。该公制(1)奖励不确定性估计,对正确断言产生高置信度,以及在不正确的断言处分配低置信水平的估计数,(2)惩罚导致更高百分比的无关正确断言百分比的不确定性措施。我们进一步基准测试由14个独立参与的Qu-Brats 2020的分割不确定性,所有这些都参与了主要的Brats细分任务。总体而言,我们的研究结果证实了不确定性估计提供了分割算法的重要性和互补价值,因此突出了医学图像分析中不确定性量化的需求。我们的评估代码在HTTPS://github.com/ragmeh11/qu-brats公开提供。
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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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因果和归因研究对于地球科学发现至关重要,对于为气候,生态和水政策提供信息至关重要。但是,当前的方法需要与科学和利益相关者挑战的复杂性以及数据可用性以及数据驱动方法的充分性相结合。除非通过物理学进行仔细的通知,否则它们会冒着将相关性与因果关系相关或因估计不准确而淹没的风险。鉴于自然实验,对照试验,干预措施和反事实检查通常是不切实际的,因此已经开发了信息理论方法,并在地球科学中不断完善。在这里,我们表明,基于转移熵的因果图最近在具有备受瞩目的发现的地球科学中变得流行,即使增强具有统计学意义,也可能是虚假的。我们开发了一种基于子样本的合奏方法,用于鲁棒性因果分析。模拟数据以及气候和生态水文中的观察表明,这种方法的鲁棒性和一致性。
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策略培训是一种多学科的康复方法,它教导技能减少中风后认知障碍者的残疾。与传统的康复方法相比,在随机,对照临床试验中已显示策略培训是促进独立性的更可行和有效的干预措施。标准化的保真度评估用于通过检查康复视频记录中的指导和定向口头提示来衡量治疗原则的依从性。尽管用于检测指导和定向的口头提示的忠诚度评估对于单一站点研究是有效的,但在大型多站点务实的务实试验中,它可能会变成劳动力密集,耗时且昂贵。为了应对广泛的战略培训实施的这一挑战,我们利用自然语言处理(NLP)技术来自动化策略培训保真度评估,即自动从康复会议的视频记录中自动识别有指导和指导的口头提示。我们开发了一种基于规则的NLP算法,一个长期术语存储器(LSTM)模型以及该任务的变压器(BERT)模型的双向编码器表示。 BERT模型以0.8075的F1得分实现了最佳性能。这项研究的发现在心理学和康复干预研究和实践方面具有广泛的希望。
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在结构健康监测中使用机器学习的情况变得越来越普遍,因为许多固有的任务(例如回归和分类)在开发基于条件的评估中自然而然地属于其职责。本章介绍了物理知识的机器学习概念,其中人们适应ML算法来说明工程师通常会试图建模或评估的结构。本章将演示将基于物理学的模型与数据驱动的模型相结合的灰色盒模型如何在SHM设置中提高预测能力。此处证明的方法的特殊优势是模型的推广能力,并具有在不同制度中增强的预测能力。这是一项需要评估的关键问题,或者监视数据不涵盖结构将经历的操作条件。本章将概述物理知识的ML,并在贝叶斯环境中引入了许多用于灰色盒子建模的方法。讨论的主要ML工具将是高斯过程回归,我们将证明如何通过约束,平均功能和内核设计以及最终在状态空间设置中通过约束来合并物理假设/模型。将展示一系列SHM应用程序,从负载监视离岸和航空航天结构的负载任务到长跨度桥梁的性能监控。
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通常通过过去的选择来告知机器学习中的评估,例如要使用哪些数据集或指标。该标准化可以使用排行榜对平等基础进行比较,但是随着出现更好的替代方案,评估选择变得不佳。这个问题在自然语言生成中尤其相关,该语言需要不断改善的数据集,指标和人类评估以提出确定性的主张。为了使遵循最佳模型评估实践更加容易,我们介绍了GEMV2。新版本的一代,评估和指标基准为数据集,模型和指标开发人员提供了模块化基础架构,以使彼此受益。GEMV2支持40种记录的数据集中51种语言。所有数据集的模型都可以在线评估,我们的交互式数据卡创建和渲染工具使得在Living Benchmark中添加新数据集变得更加容易。
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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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There is an increasing interest in developing artificial intelligence (AI) systems to process and interpret electronic health records (EHRs). Natural language processing (NLP) powered by pretrained language models is the key technology for medical AI systems utilizing clinical narratives. However, there are few clinical language models, the largest of which trained in the clinical domain is comparatively small at 110 million parameters (compared with billions of parameters in the general domain). It is not clear how large clinical language models with billions of parameters can help medical AI systems utilize unstructured EHRs. In this study, we develop from scratch a large clinical language model - GatorTron - using >90 billion words of text (including >82 billion words of de-identified clinical text) and systematically evaluate it on 5 clinical NLP tasks including clinical concept extraction, medical relation extraction, semantic textual similarity, natural language inference (NLI), and medical question answering (MQA). We examine how (1) scaling up the number of parameters and (2) scaling up the size of the training data could benefit these NLP tasks. GatorTron models scale up the clinical language model from 110 million to 8.9 billion parameters and improve 5 clinical NLP tasks (e.g., 9.6% and 9.5% improvement in accuracy for NLI and MQA), which can be applied to medical AI systems to improve healthcare delivery. The GatorTron models are publicly available at: https://catalog.ngc.nvidia.com/orgs/nvidia/teams/clara/models/gatortron_og.
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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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