Robustness

鲁棒性
  • 文章类型: Journal Article
    本文提出了一种基于模型的优化方法,用于挤压过程中汽车密封件的生产。高产量,再加上质量约束和过程固有的不确定性,鼓励搜索最小化不合格的操作条件。主要的不确定性来自工艺的可变性和原材料本身。所提出的方法,基于贝叶斯优化,考虑这些因素,并获得一组强大的过程参数。由于执行详细模拟的高计算成本和复杂性,使用降阶模型来解决优化问题。该提案已在虚拟环境中进行了评估,其中已被证实能够最小化过程不确定性的影响。特别是,它将显著提高产品的质量,而不会产生额外的成本,与通过确定性优化算法获得的解决方案相比,实现了50%的尺寸公差。
    This paper proposes a model-based optimization method for the production of automotive seals in an extrusion process. The high production throughput, coupled with quality constraints and the inherent uncertainty of the process, encourages the search for operating conditions that minimize nonconformities. The main uncertainties arise from the process variability and from the raw material itself. The proposed method, which is based on Bayesian optimization, takes these factors into account and obtains a robust set of process parameters. Due to the high computational cost and complexity of performing detailed simulations, a reduced order model is used to address the optimization. The proposal has been evaluated in a virtual environment, where it has been verified that it is able to minimize the impact of process uncertainties. In particular, it would significantly improve the quality of the product without incurring additional costs, achieving a 50% tighter dimensional tolerance compared to a solution obtained by a deterministic optimization algorithm.
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  • 文章类型: Journal Article
    即使已经确定hyetograph的形状会影响水文模拟的结果,常见的工程实践并不总是解释这一事实。相反,通常认为单个设计风暴足以设计城市排水系统。本研究考察了这种设计范式的影响,结合设计过程中主观选择引入的不确定性,具有设计系统的鲁棒性。要做到这一点,我们评估了一组由工程专业学生创建的个人设计,使用相同的芝加哥hyetograph作为设计风暴。然后,我们创建了降水量和持续时间与芝加哥降水量仪相同的降水量仪集合,并评估了设计的水文响应。结果表明,设计,在最初的设计风暴中表现同样出色,引发了对乐团风暴的不同反应,因此,表现出不同程度的鲁棒性,暗示需要适应当前的设计方法。
    Even though it has been established that a hyetograph\'s shape affects the results of hydrological simulations, common engineering practice does not always account for this fact. Instead, a single design storm is often considered sufficient for designing a urban drainage system. This study examines the impact that this design paradigm, combined with the uncertainty introduced by subjective choices made during the design process, has on the robustness of a designed system. To do so, we evaluated a set of individual designs created by engineering students using the same Chicago hyetograph as a design storm. We then created ensembles of hyetographs with the same precipitation volume and duration as the Chicago hyetograph and evaluated the designs\' hydrological responses. The results showed that designs, which performed equally well for the initial design storm, triggered varying responses for the storms in the ensembles and, consequently, showed different levels of robustness, hinting at a need to adapt the current design approach.
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  • 文章类型: Journal Article
    MR引导的放射治疗增加了磁共振成像(MRI)的精度,使线性加速器的治疗益处。在每次治疗之前,MRI可以生成大量的成像数据以供分析。影像组学站在医学成像和肿瘤学研究的最前沿,致力于挖掘定量成像属性以伪造预测模型。然而,这些模型的鲁棒性经常受到挑战。
    为了评估特征提取的鲁棒性,我们使用0.35TMR直线加速器系统进行了可重复性研究,同时使用专门的体模和患者衍生的图像,关注胰腺癌病例。我们提取了基于形状的,来自患者衍生图像的一阶和纹理特征,以及来自幻影衍生图像的仅一阶和纹理特征。还通过等效性测试评估了模拟和第一部分图像之间的延迟的影响。
    从评估的107个功能中,58(54%)被认为是不可再现的:18在体模和患者图像中一致不一致,9个特定于基于幻影的分析,和31到患者派生的数据。
    我们的发现表明,从该双重数据集中提取的显着比例的放射学特征是不可靠的。至关重要的是丢弃这些不可重复的元素,以完善和增强放射学模型的开发,特别是对于胰腺癌的MR引导放疗。
    UNASSIGNED: MR-guided radiotherapy adds the precision of magnetic resonance imaging (MRI) to the therapeutic benefits of a linear accelerator. Prior to each therapeutic session, an MRI generates a significant volume of imaging data ripe for analysis. Radiomics stands at the forefront of medical imaging and oncology research, dedicated to mining quantitative imaging attributes to forge predictive models. However, the robustness of these models is often challenged.
    UNASSIGNED: To assess the robustness of feature extraction, we conducted reproducibility studies using a 0.35 T MR-linac system, employing both a specialized phantom and patient-derived images, focusing on cases of pancreatic cancer. We extracted shape-based, first-order and textural features from patient-derived images and only first-order and textural features from phantom-derived images. The impact of the delay between simulation and first fraction images was also assessed with an equivalence test.
    UNASSIGNED: From 107 features evaluated, 58 (54 %) were considered as non-reproducible: 18 were uniformly inconsistent across both phantom and patient images, 9 were specific to phantom-based analysis, and 31 to patient-derived data.
    UNASSIGNED: Our findings show that a significant proportion of radiomic features extracted from this dual dataset were unreliable. It is essential to discard these non-reproducible elements to refine and enhance radiomic model development, particularly for MR-guided radiotherapy in pancreatic cancer.
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  • 文章类型: Journal Article
    研究U-Net模型在医学图像合成中对对抗扰动的鲁棒性,这项研究介绍了RobMedNAS,一种用于识别弹性U-Net配置的神经架构搜索策略。通过对MRI合成CT数据的回顾性分析,在关键解剖区域采用骰子系数和平均绝对误差度量,该研究评估了传统的U-Net模型和对抗攻击下的RobMedNAS优化模型。研究结果表明,RobMedNAS在不影响准确性的情况下增强U-Net弹性的功效,提出了一种鲁棒医学图像处理的新途径。 .
    Investigating U-Net model robustness in medical image synthesis against adversarial perturbations, this study introduces RobMedNAS, a neural architecture search strategy for identifying resilient U-Net configurations. Through retrospective analysis of synthesized CT from MRI data, employing Dice coefficient and mean absolute error metrics across critical anatomical areas, the study evaluates traditional U-Net models and RobMedNAS-optimized models under adversarial attacks. Findings demonstrate RobMedNAS\'s efficacy in enhancing U-Net resilience without compromising on accuracy, proposing a novel pathway for robust medical image processing. .
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  • 文章类型: Journal Article
    基于非刚性表面的软组织配准对于手术导航系统至关重要,但是由于大量的自由度以及术中数据中存在的连续变化和复杂的表面结构,因此其采用仍然面临着一些挑战。通过采用非严格的注册,外科医生可以将术前图像整合到术中指导环境中,在共同的坐标系中提供患者复杂的术前和术中解剖结构的实时可视化,以提高导航精度。然而,许多现有的注册方法,包括肝脏应用,更广泛的社区无法进入。为了解决这个限制,我们对几种开源软件进行了比较分析,基于非刚性表面的肝脏配准算法,总体目标是对比他们的优势和劣势,并确定最佳解决方案。我们比较了三种基于优化和一种数据驱动的非刚性配准算法的鲁棒性,以响应降低的可见性比率(减少的表面部分视图)和增加的变形水平(平均位移),报告为术前和术中肝表面之间的均方根误差(RMSE)。我们的结果表明,高斯混合模型-有限元模型(GMM-FEM)方法在可见性比率降低和术中表面位移增加的情况下,始终比其他三种测试方法产生更低的配准后误差。因此为术前非刚性肝脏表面配准提供了一个潜在的有希望的解决方案。
    Non-rigid surface-based soft tissue registration is crucial for surgical navigation systems, but its adoption still faces several challenges due to the large number of degrees of freedom and the continuously varying and complex surface structures present in the intra-operative data. By employing non-rigid registration, surgeons can integrate the pre-operative images into the intra-operative guidance environment, providing real-time visualization of the patient\'s complex pre- and intra-operative anatomy in a common coordinate system to improve navigation accuracy. However, many of the existing registration methods, including those for liver applications, are inaccessible to the broader community. To address this limitation, we present a comparative analysis of several open-source, non-rigid surface-based liver registration algorithms, with the overall goal of contrasting their strength and weaknesses and identifying an optimal solution. We compared the robustness of three optimization-based and one data-driven nonrigid registration algorithms in response to a reduced visibility ratio (reduced partial views of the surface) and to an increasing deformation level (mean displacement), reported as the root mean square error (RMSE) between the pre-and intra-operative liver surface meshed following registration. Our results indicate that the Gaussian Mixture Model - Finite Element Model (GMM-FEM) method consistently yields a lower post-registration error than the other three tested methods in the presence of both reduced visibility ratio and increased intra-operative surface displacement, therefore offering a potentially promising solution for pre- to intra-operative nonrigid liver surface registration.
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  • 文章类型: Journal Article
    现代神经网络对随机噪声和蓄意攻击的脆弱性引起了人们对其鲁棒性的担忧,特别是它们越来越多地用于安全和安全关键应用。尽管最近的研究努力通过对抗性示例的重新训练或采用数据增强技术来增强鲁棒性,对训练数据扰动对模型鲁棒性的影响的全面研究仍然缺乏。本文提出了第一个广泛的实证研究,调查了模型再训练过程中数据扰动的影响。实验分析侧重于随机和对抗鲁棒性,遵循稳健性分析领域的既定做法。探索了数据集不同方面的各种类型的扰动,包括输入,标签,和抽样分布。进行单因素和多因素实验来评估个体扰动及其组合。这些发现为构建高质量的训练数据集提供了见解,以优化鲁棒性,并推荐适当程度的训练集扰动,以平衡鲁棒性和正确性,并有助于理解深度学习中的模型鲁棒性,并为通过扰动再训练增强模型性能提供实践指导,促进为安全关键型应用开发更可靠、更值得信赖的深度学习系统。
    The vulnerability of modern neural networks to random noise and deliberate attacks has raised concerns about their robustness, particularly as they are increasingly utilized in safety- and security-critical applications. Although recent research efforts were made to enhance robustness through retraining with adversarial examples or employing data augmentation techniques, a comprehensive investigation into the effects of training data perturbations on model robustness remains lacking. This paper presents the first extensive empirical study investigating the influence of data perturbations during model retraining. The experimental analysis focuses on both random and adversarial robustness, following established practices in the field of robustness analysis. Various types of perturbations in different aspects of the dataset are explored, including input, label, and sampling distribution. Single-factor and multi-factor experiments are conducted to assess individual perturbations and their combinations. The findings provide insights into constructing high-quality training datasets for optimizing robustness and recommend the appropriate degree of training set perturbations that balance robustness and correctness, and contribute to understanding model robustness in deep learning and offer practical guidance for enhancing model performance through perturbed retraining, promoting the development of more reliable and trustworthy deep learning systems for safety-critical applications.
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  • 文章类型: Journal Article
    研究人员使用的大量不同的分析选择部分原因是神经影像学研究中复制的挑战。对于详尽的稳健性分析,了解分析选项的全部空间是至关重要的。我们进行了系统的文献综述,以确定认知网络神经科学新兴领域功能神经影像学数据预处理和分析中的分析决策。我们发现了61个不同的步骤,其中17个有争议的参数选择。擦洗,全局信号回归,和空间平滑是有争议的步骤之一。没有应用不同步骤的标准化顺序,并且几个步骤中的参数设置在不同的研究中差异很大。通过汇总研究中的管道,我们提出了三个分类层次来对分析选择进行分类:1)包括或排除具体步骤,2)在步骤内进行参数调整,和3)步骤的不同顺序。我们开发了一种具有很高教育价值的决策支持应用程序,称为METEOR,以促进对数据的访问,以设计消息灵通的鲁棒性(多重)分析。
    The large number of different analytical choices used by researchers is partly responsible for the challenge of replication in neuroimaging studies. For an exhaustive robustness analysis, knowledge of the full space of analytical options is essential. We conducted a systematic literature review to identify the analytical decisions in functional neuroimaging data preprocessing and analysis in the emerging field of cognitive network neuroscience. We found 61 different steps, with 17 of them having debatable parameter choices. Scrubbing, global signal regression, and spatial smoothing are among the controversial steps. There is no standardized order in which different steps are applied, and the parameter settings within several steps vary widely across studies. By aggregating the pipelines across studies, we propose three taxonomic levels to categorize analytical choices: 1) inclusion or exclusion of specific steps, 2) parameter tuning within steps, and 3) distinct sequencing of steps. We have developed a decision support application with high educational value called METEOR to facilitate access to the data in order to design well-informed robustness (multiverse) analysis.
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  • 文章类型: Journal Article
    超疏水表面在水下减阻方面具有巨大潜力。然而,随着雷诺数的增加,减阻率降低,甚至可能导致阻力增加。原因在于空气床垫的崩溃。为了解决这个问题,本文开发了具有楔形微槽的金字塔形鲁棒超疏水表面,其在浸没在水下时表现出高气体分数,并且在充气床垫塌陷的情况下通过空气补充实现充气床垫的完全铺展和恢复的良好能力。在水隧道中进行的压降测试证实,在连续注气的情况下,在层流条件下减阻达到64.8%,在没有空气注入的情况下,基本上大于38.4%,在湍流中可以实现50.8%的减阻。这一结果突出了超疏水表面与气垫恢复减阻的潜在应用。
    Superhydrophobic surfaces hold immense potential in underwater drag reduction. However, as the Reynolds number increases, the drag reduction rate decreases, and it may even lead to a drag increase. The reason lies in the collapse of the air mattress. To address this issue, this paper develops a pyramid-shaped robust superhydrophobic surface with wedged microgrooves, which exhibits a high gas fraction when immersed underwater and good ability to achieve complete spreading and recovery of the air mattress through air replenishment in the case of collapse of the air mattress. Pressure drop tests in a water tunnel confirm that with continuous air injection, the drag reduction reaches 64.8% in laminar flow conditions, substantially greater than 38.4% in the case without air injection, and can achieve 50.8% drag reduction in turbulent flow. This result highlights the potential applications of superhydrophobic surfaces with air mattress recovery for drag reduction.
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  • 文章类型: Journal Article
    反向着色为探索管道化的分子机制提供了机会。在这项研究中,在乳草虫的配相着色中探索了表观遗传调控潜在稳健性的作用,筋膜盘。Polycomb(Pc)和zeste增强剂(E(z)),分别编码Polycomb抑制复合物1(PRC1)和PRC2的成分,而京,它编码PRC2.2亚复合物的一个组成部分,被击倒在O.fasciatus的第四龄。这些基因的敲除导致小脑形态和黑化的改变。特别是,当PC被撞倒时,成年人的腹部高度黑化,头部和前爪在所有温度检查。相比之下,在不同温度下,E(z)和jing击倒导致背前黑化的可塑性增加。此外,精敲成虫在头部和胸部的背侧黑化表现出增加的可塑性。这些观察结果表明,组蛋白修饰剂可能在管道化过程中起关键作用,以赋予配相着色的鲁棒性。
    Aposematic coloration offers an opportunity to explore the molecular mechanisms underlying canalization. In this study, the role of epigenetic regulation underlying robustness was explored in the aposematic coloration of the milkweed bug, Oncopeltus fasciatus. Polycomb (Pc) and Enhancer of zeste (E(z)), which encode components of the Polycomb repressive complex 1 (PRC1) and PRC2, respectively, and jing, which encodes a component of the PRC2.2 subcomplex, were knocked down in the fourth instar of O. fasciatus. Knockdown of these genes led to alterations in scutellar morphology and melanization. In particular, when Pc was knocked down, the adults developed a highly melanized abdomen, head and forewings at all temperatures examined. In contrast, the E(z) and jing knockdown led to increased plasticity of the dorsal forewing melanization across different temperatures. Moreover, jing knockdown adults exhibited increased plasticity in the dorsal melanization of the head and the thorax. These observations demonstrate that histone modifiers may play a key role during the process of canalization to confer robustness in the aposematic coloration.
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  • 文章类型: Journal Article
    分析,准确,精确,具体,已开发并验证了高效,简单的超高效液相色谱法用于批量测定帕唑帕尼,并已用于市售药物剂型。用于色谱运行的流动相由0.1%OPA缓冲液和乙腈组成,比例为30:70%v/v。使用等度模式在BHELUPLC柱上实现分离。帕唑帕尼药物峰被很好地分离并且通过PDA检测器在256nm处检测。所开发的方法在6-14μg/ml的浓度范围内呈线性关系。该方法已根据ICH关于系统适用性的指南进行了验证。特异性,精度,准确性和鲁棒性。帕唑帕尼的LOD和LOQ分别为0.5853µg/ml和1.7738µg/ml。所开发的方法简单,精确,具体,准确快速,使其适合于估计散装和上市的药物剂型剂型中的帕唑帕尼。
    An analytical, accurate, precise, specific, efficient and simple Ultra-Performance Liquid Chromatography method has been developed and validated for the determination of Pazopanib in bulk and was applied on marketed Pharmaceutical Dosage form. The mobile phase used for the chromatographic runs consisted of 0.1% OPA Buffer and Acetonitrile in the ratio of 30:70% v/v. The separation was achieved on a BHEL UPLC column using isocratic mode. Pazopanib Drug peak were well separated and were detected by a PDA detector at 256 nm. The developed method was linear at the concentration range 6-14 μg/ml for Pazopanib. The method has been validated according to ICH guidelines with respect to system suitability, specificity, precision, accuracy and robustness. The LOD and LOQ for the Pazopanib were found to be 0.5853 µg/ml and 1.7738µg/ml respectively. The developed method is simple, precise, specific, accurate and rapid, making it suitable for estimation of Pazopanib in bulk and marketed pharmaceutical dosage form dosage form.
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