自适应实验可以增加当前学生从教学干预的现场实验中获得更好结果的机会。在此类实验中,在收集更多数据时将学生分配到条件变化的可能性,因此可以将学生分配给可能表现更好的干预措施。数字教育环境降低了进行此类适应性实验的障碍,但很少在教育中应用。原因之一可能是研究人员可以访问很少的现实案例研究,这些案例研究说明了在特定情况下这些实验的优势和缺点。我们通过使用Thompson采样算法进行自适应实验来评估学生在学生中提醒的效果,并将其与传统的统一随机实验进行比较。我们将其作为有关如何进行此类实验的案例研究,并提出了有关自适应随机实验可能或多或少有用的条件的一系列开放问题。
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在教育环境中进行随机实验提出了一个问题,即我们如何使用机器学习技术来改善教育干预措施。使用自适应实验中的汤普森采样(TS)(TS)等多臂匪徒(MAB)算法,即使在干预完成之前,也可以通过增加对最佳状态(ARM)的分配可能性来获得更好的结果的机会。这是比传统的A/B测试的优势,该测试可能会分配相等数量的学生为最佳和非最佳条件。问题是勘探探索权衡取舍。尽管自适应政策旨在收集足够的信息来分配更多的学生以可靠地提供更好的武器,但过去的工作表明,这可能还不够探索,无法就武器是否有所不同,得出可靠的结论。因此,在整个实验中提供额外的均匀随机(UR)探索是很有趣的。本文展示了一个真实的自适应实验,该实验是关于学生如何与教师每周的电子邮件提醒互动以建立时间管理习惯的。我们感兴趣的指标是打开电子邮件率,它跟踪由不同主题行的武器。这些是按照不同的分配算法传递的:ur,ts和我们确定为ts {\ dag} - 结合了TS和UR奖励以更新其先验者。我们强调了这些自适应算法的问题 - 在没有显着差异时可能会剥削手臂 - 并解决它们的原因和后果。未来的方向包括研究最佳臂的早期选择不是理想的情况以及自适应算法如何解决它们的情况。
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像汤普森采样等多武装强盗算法可用于进行自适应实验,其中最大化奖励意味着数据用于逐步为更多参与者分配更有效的武器。这些转让策略增加了统计假设试验的风险,鉴定武器之间的差异,当没有一个时,并且在真正是一个是一个时,武器的差异存在差异。我们为2臂实验仿真,探讨了两种算法,这些算法结合了统计分析的均匀随机化的益处,具有通过Thompson采样(TS)实现的奖励最大化的益处。首先,前两种汤普森采样增加了固定量的均匀随机分配(UR)随时间均匀传播。二,一种新的启发式算法,称为TS Postdiff(差异后概率)。 Ts Postdiff采用贝叶斯方法来混合TS和UR:使用UR分配分配参与者的概率是后部概率,即两个臂之间的差异是“小”(低于某个阈值),允许在存在时探索更多的探索很少或没有奖励获得。我们发现TS PostDiff方法跨多种效果大小进行良好,因此不需要根据真实效果大小的猜测进行调整。
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Novel topological spin textures, such as magnetic skyrmions, benefit from their inherent stability, acting as the ground state in several magnetic systems. In the current study of atomic monolayer magnetic materials, reasonable initial guesses are still needed to search for those magnetic patterns. This situation underlines the need to develop a more effective way to identify the ground states. To solve this problem, in this work, we propose a genetic-tunneling-driven variance-controlled optimization approach, which combines a local energy minimizer back-end and a metaheuristic global searching front-end. This algorithm is an effective optimization solution for searching for magnetic ground states at extremely low temperatures and is also robust for finding low-energy degenerated states at finite temperatures. We demonstrate here the success of this method in searching for magnetic ground states of 2D monolayer systems with both artificial and calculated interactions from density functional theory. It is also worth noting that the inherent concurrent property of this algorithm can significantly decrease the execution time. In conclusion, our proposed method builds a useful tool for low-dimensional magnetic system energy optimization.
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The release of ChatGPT, a language model capable of generating text that appears human-like and authentic, has gained significant attention beyond the research community. We expect that the convincing performance of ChatGPT incentivizes users to apply it to a variety of downstream tasks, including prompting the model to simplify their own medical reports. To investigate this phenomenon, we conducted an exploratory case study. In a questionnaire, we asked 15 radiologists to assess the quality of radiology reports simplified by ChatGPT. Most radiologists agreed that the simplified reports were factually correct, complete, and not potentially harmful to the patient. Nevertheless, instances of incorrect statements, missed key medical findings, and potentially harmful passages were reported. While further studies are needed, the initial insights of this study indicate a great potential in using large language models like ChatGPT to improve patient-centered care in radiology and other medical domains.
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Efficient surrogate modelling is a key requirement for uncertainty quantification in data-driven scenarios. In this work, a novel approach of using Sparse Random Features for surrogate modelling in combination with self-supervised dimensionality reduction is described. The method is compared to other methods on synthetic and real data obtained from crashworthiness analyses. The results show a superiority of the here described approach over state of the art surrogate modelling techniques, Polynomial Chaos Expansions and Neural Networks.
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Purpose: Tracking the 3D motion of the surgical tool and the patient anatomy is a fundamental requirement for computer-assisted skull-base surgery. The estimated motion can be used both for intra-operative guidance and for downstream skill analysis. Recovering such motion solely from surgical videos is desirable, as it is compliant with current clinical workflows and instrumentation. Methods: We present Tracker of Anatomy and Tool (TAToo). TAToo jointly tracks the rigid 3D motion of patient skull and surgical drill from stereo microscopic videos. TAToo estimates motion via an iterative optimization process in an end-to-end differentiable form. For robust tracking performance, TAToo adopts a probabilistic formulation and enforces geometric constraints on the object level. Results: We validate TAToo on both simulation data, where ground truth motion is available, as well as on anthropomorphic phantom data, where optical tracking provides a strong baseline. We report sub-millimeter and millimeter inter-frame tracking accuracy for skull and drill, respectively, with rotation errors below 1{\deg}. We further illustrate how TAToo may be used in a surgical navigation setting. Conclusion: We present TAToo, which simultaneously tracks the surgical tool and the patient anatomy in skull-base surgery. TAToo directly predicts the motion from surgical videos, without the need of any markers. Our results show that the performance of TAToo compares favorably to competing approaches. Future work will include fine-tuning of our depth network to reach a 1 mm clinical accuracy goal desired for surgical applications in the skull base.
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Selecting the number of topics in LDA models is considered to be a difficult task, for which alternative approaches have been proposed. The performance of the recently developed singular Bayesian information criterion (sBIC) is evaluated and compared to the performance of alternative model selection criteria. The sBIC is a generalization of the standard BIC that can be implemented to singular statistical models. The comparison is based on Monte Carlo simulations and carried out for several alternative settings, varying with respect to the number of topics, the number of documents and the size of documents in the corpora. Performance is measured using different criteria which take into account the correct number of topics, but also whether the relevant topics from the DGPs are identified. Practical recommendations for LDA model selection in applications are derived.
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Previous work has shown the potential of deep learning to predict renal obstruction using kidney ultrasound images. However, these image-based classifiers have been trained with the goal of single-visit inference in mind. We compare methods from video action recognition (i.e. convolutional pooling, LSTM, TSM) to adapt single-visit convolutional models to handle multiple visit inference. We demonstrate that incorporating images from a patient's past hospital visits provides only a small benefit for the prediction of obstructive hydronephrosis. Therefore, inclusion of prior ultrasounds is beneficial, but prediction based on the latest ultrasound is sufficient for patient risk stratification.
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Prostate cancer is the most common cancer in men worldwide and the second leading cause of cancer death in the United States. One of the prognostic features in prostate cancer is the Gleason grading of histopathology images. The Gleason grade is assigned based on tumor architecture on Hematoxylin and Eosin (H&E) stained whole slide images (WSI) by the pathologists. This process is time-consuming and has known interobserver variability. In the past few years, deep learning algorithms have been used to analyze histopathology images, delivering promising results for grading prostate cancer. However, most of the algorithms rely on the fully annotated datasets which are expensive to generate. In this work, we proposed a novel weakly-supervised algorithm to classify prostate cancer grades. The proposed algorithm consists of three steps: (1) extracting discriminative areas in a histopathology image by employing the Multiple Instance Learning (MIL) algorithm based on Transformers, (2) representing the image by constructing a graph using the discriminative patches, and (3) classifying the image into its Gleason grades by developing a Graph Convolutional Neural Network (GCN) based on the gated attention mechanism. We evaluated our algorithm using publicly available datasets, including TCGAPRAD, PANDA, and Gleason 2019 challenge datasets. We also cross validated the algorithm on an independent dataset. Results show that the proposed model achieved state-of-the-art performance in the Gleason grading task in terms of accuracy, F1 score, and cohen-kappa. The code is available at https://github.com/NabaviLab/Prostate-Cancer.
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