calibration

校准
  • 文章类型: Journal Article
    用于估计作物模型参数的观测数据集的适当组合可以在确保准确性的同时降低计算成本。本研究旨在探讨观察到的物候阶段的不同组合对品种特异性参数(CPSs)估算的定量影响。我们使用CROPGRO-大豆物候模型(CSPM)作为案例研究,并结合了广义似然不确定性估计(GLUE)方法。四个观测物候阶段的不同组合,包括最初的开花,初始pod,初始颗粒,和来自Exp的五个大豆品种的初始成熟阶段。1和Exp。表2中描述的图3分别用于校准CSP。CSPM,由优化的CSP驱动,然后针对来自Exp的两个独立的物候数据集进行评估。2和Exp。4在表2中描述。均方根误差(RMSE)(平均绝对误差(MAE),决定系数(R2),纳什·萨特克利夫模型效率(NSE))为15.50(14.63、0.96、0.42),4.76(3.92,0.97,0.95),4.69(3.72,0.98,0.95),3.91(3.40、0.99、0.96)和12.54(11.67、0.95、0.60),5.07(4.61,0.98,0.93),4.97(4.28,0.97,0.94),4.58(4.02,0.98,0.95)使用一个,两个,三,在CSP估计中观察到四个物候阶段。评价结果表明,RMSE和MAE下降,R2和NSE随着用于参数校准的观测物候阶段数的增加而增加。然而,RMSE(MAE,NSE)使用两个,三,和四个观察阶段。通过使用至少两个观察到的物候阶段平衡校准效果和计算成本来获得用于CSMP的相对可靠的优化CSP。这些发现为作物模型的参数估计提供了新的见解。
    Suitable combinations of observed datasets for estimating crop model parameters can reduce the computational cost while ensuring accuracy. This study aims to explore the quantitative influence of different combinations of the observed phenological stages on estimation of cultivar-specific parameters (CPSs). We used the CROPGRO-Soybean phenological model (CSPM) as a case study in combination with the Generalized Likelihood Uncertainty Estimation (GLUE) method. Different combinations of four observed phenological stages, including initial flowering, initial pod, initial grain, and initial maturity stages for five soybean cultivars from Exp. 1 and Exp. 3 described in Table 2 are respectively used to calibrate the CSPs. The CSPM, driven by the optimized CSPs, is then evaluated against two independent phenological datasets from Exp. 2 and Exp. 4 described in Table 2. Root means square error (RMSE) (mean absolute error (MAE), coefficient of determination (R2), and Nash Sutcliffe model efficiency (NSE)) are 15.50 (14.63, 0.96, 0.42), 4.76 (3.92, 0.97, 0.95), 4.69 (3.72, 0.98, 0.95), 3.91 (3.40, 0.99, 0.96) and 12.54 (11.67, 0.95, 0.60), 5.07 (4.61, 0.98, 0.93), 4.97 (4.28, 0.97, 0.94), 4.58 (4.02, 0.98, 0.95) for using one, two, three, and four observed phenological stages in the CSPs estimation. The evaluation results suggest that RMSE and MAE decrease, and R2 and NSE increase with the increase in the number of observed phenological stages used for parameter calibration. However, there is no significant reduction in the RMSEs (MAEs, NSEs) using two, three, and four observed stages. Relatively reliable optimized CSPs for CSMP are obtained by using at least two observed phenological stages balancing calibration effect and computational cost. These findings provide new insight into parameter estimation of crop models.
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  • 文章类型: Journal Article
    基于预测模型的风险分层在预防和管理慢性病中变得越来越重要。然而,由于成本和时间的限制,并非每个人都有资源来收集大量人群的足够详细的个人层面信息,以开发风险预测模型。一种更实用的方法是使用从现有研究中开发的预测模型,并用目标人群的相关摘要级信息对其进行校准。许多现有的研究是在基于人群的病例对照设计下进行的。Gail等人。(JNatlCancerInst81:1879-1886,1989)提出将从病例对照数据中获得的比值比估计和目标人群的疾病发病率相结合,以获得基线风险函数,从而导致疾病的纯粹风险。然而,该方法要求来自病例对照研究的病例的风险因素分布与目标人群相同,which,如果违反,可能会产生有偏差的风险估计。在这篇文章中,我们提出了两种新颖的加权估计方程方法,通过利用(一些)危险因素的汇总信息以及目标人群的无病概率来校准基线风险.我们建立了所提出的估计量的一致性和渐近正态。广泛的模拟研究和在结直肠癌研究中的应用表明,所提出的估计器在有限样本中的偏倚减少方面表现良好。
    Risk stratification based on prediction models has become increasingly important in preventing and managing chronic diseases. However, due to cost- and time-limitations, not every population can have resources for collecting enough detailed individual-level information on a large number of people to develop risk prediction models. A more practical approach is to use prediction models developed from existing studies and calibrate them with relevant summary-level information of the target population. Many existing studies were conducted under the population-based case-control design. Gail et al. (J Natl Cancer Inst 81:1879-1886, 1989) proposed to combine the odds ratio estimates obtained from case-control data and the disease incidence rates from the target population to obtain the baseline hazard function, and thereby the pure risk for developing diseases. However, the approach requires the risk factor distribution of cases from the case-control studies be same as the target population, which, if violated, may yield biased risk estimation. In this article, we propose two novel weighted estimating equation approaches to calibrate the baseline risk by leveraging the summary information of (some) risk factors in addition to disease-free probabilities from the targeted population. We establish the consistency and asymptotic normality of the proposed estimators. Extensive simulation studies and an application to colorectal cancer studies demonstrate the proposed estimators perform well for bias reduction in finite samples.
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  • 文章类型: Journal Article
    目的:本研究旨在研究机器人计算机辅助植入手术(r-CAIS)立即植入的准确性。
    方法:需要立即在上颌前部植入的患者被纳入r-CAIS。手术前,患者进行了带有定位标记的锥形束计算机断层扫描(CBCT)扫描.计划了虚拟植入物放置位置和钻孔顺序。在空间配准和校准之后,植入物与机器人系统一起放置在外科医生的监督下。进行术后CBCT以确定放置的植入物位置。虚拟计划和实际放置的植入物的DICOM数据通过机器人系统的准确性验证软件进行叠加和配准。精度是自动计算的。中远端的偏差,唇腭,并记录了冠状方向。
    结果:纳入15例患者,20个植入物。未报告不良手术事件或术后并发症。全球平台,顶点,角度偏差为0.75±0.20mm(95%CI:0.65至0.84mm),0.70±0.27mm(95%CI:0.57至0.82mm),和1.17±0.73°(95%CI:0.83至1.51°),分别。此外,垂直平台和顶点偏差为0.50±0.31mm,(95%CI:0.35至0.64毫米)和0.48±0.32毫米,(95%CI:0.33至0.63毫米),分别。所有放置的植入物位置都比计划的位置更靠唇和顶端,分别。
    结论:使用机器人系统可以实现立即植入的高精度。
    结论:我们的研究提供了重要的证据来支持机器人系统在植入物放置中的潜力,即使在技术上具有挑战性的眼前场景中。
    This study aimed to investigate the accuracy of a robotic computer-assisted implant surgery (r-CAIS) for immediate implant placement.
    Patients requiring immediate implant placement in the maxillary anterior region were enrolled for r-CAIS. Before surgery, the patients underwent a cone beam computed tomography (CBCT) scan with a positioning marker. Virtual implant placement position and drilling sequences were planned. Following spatial registration and calibration, the implants were placed with the robotic system under supervision. A postoperative CBCT was taken to control the actual implant positions. The DICOM data of the virtually planned and the actually placed implant were superimposed and registered through the accuracy verification software of the robotic system. The accuracy was calculated automatically. The deviation at the mesial-distal, labial-palatal, and apico-coronal directions were recorded.
    Fifteen patients with 20 implants were included. No adverse surgical events or postoperative complications were reported. The global platform, apex, and angular deviation were 0.75 ± 0.20 mm (95 % CI: 0.65 to 0.84 mm), 0.70 ± 0.27 mm (95 % CI: 0.57 to 0.82 mm), and 1.17 ± 0.73° (95 % CI: 0.83 to 1.51°), respectively. Moreover, the vertical platform and apex deviation were 0.50 ± 0.31 mm, (95 % CI: 0.35 to 0.64 mm) and 0.48 ± 0.32 mm, (95 % CI: 0.33 to 0.63 mm), respectively. All the placed implant positions were further labial and apical than the planned ones, respectively.
    High accuracy of immediate implant placement was achieved with the robotic system.
    Our study provided evidence to support the potential of the robotic system in implant placement, even in challenging scenarios.
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  • 文章类型: Journal Article
    病例队列设计仅在病例和整个队列的随机样本(子队列)上获得完整的协变量数据。随后的出版物描述了使用分层和重量校准来提高Cox模型对数相对危害估计的效率,并且已经有一些估计纯风险的工作。然而,在医学文献中很少有这些选择的例子,我们目前找不到在线程序来分析这些不同的选项。因此,我们提出了一种统一的方法和R软件来促进这种分析。我们使用了适用于各种设计和分析选项的影响函数,以及考虑了两阶段采样的方差计算。这项工作阐明了广泛使用的Barlow(Biometrics50:1064-1072,1994)的“鲁棒”方差估计何时是合适的。相应的R软件,CaseCohortCoxSurvival,便于进行和不进行分层和/或重量校准的分析,对于有或没有替换的子队列抽样。对于分层设计,我们还允许随机丢失第二阶段数据。我们不仅提供Cox模型中对数相对危险的推断,而且对于累积基线风险和协变量特异性纯风险也是如此。我们希望这些计算和软件将促进更有效,更有原则的设计和分析选项的更广泛使用案例队列研究。
    The case-cohort design obtains complete covariate data only on cases and on a random sample (the subcohort) of the entire cohort. Subsequent publications described the use of stratification and weight calibration to increase efficiency of estimates of Cox model log-relative hazards, and there has been some work estimating pure risk. Yet there are few examples of these options in the medical literature, and we could not find programs currently online to analyze these various options. We therefore present a unified approach and R software to facilitate such analyses. We used influence functions adapted to the various design and analysis options together with variance calculations that take the two-phase sampling into account. This work clarifies when the widely used \"robust\" variance estimate of Barlow (Biometrics 50:1064-1072, 1994) is appropriate. The corresponding R software, CaseCohortCoxSurvival, facilitates analysis with and without stratification and/or weight calibration, for subcohort sampling with or without replacement. We also allow for phase-two data to be missing at random for stratified designs. We provide inference not only for log-relative hazards in the Cox model, but also for cumulative baseline hazards and covariate-specific pure risks. We hope these calculations and software will promote wider use of more efficient and principled design and analysis options for case-cohort studies.
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  • 文章类型: Journal Article
    基于LC-MS的方法已成为定量食物过敏原的优选方法。然而,传统校准曲线(MSCC)的制备是劳动密集型且容易出错的。这里,开发并验证了一种灵敏而可靠的LC-MS/MS方法,用于定量10种主要食物过敏原,其中使用单样品多点外部校准曲线(OSCC)代替MSCC。通过采用多重同位素反应监测(MIRM)技术,空白中只有一个加标水平,可以有效地建立OSCC。结果表明,所提出的方法在选择性方面表现出优异的性能,灵敏度,准确度,和精度,与传统MSCC相媲美。此外,该策略允许通过监测不太丰富的MIRM通道来稀释同位素样品。此外,该方法已成功应用于商业食品中10种食品过敏原的污染调查。凭借其高吞吐量和鲁棒性,MIRM-OSCC-LC-MS/MS方法具有许多潜在的应用,特别是在基于MS的蛋白质定量分析中。
    The LC-MS-based method has emerged as the preferred approach for quantifying food allergens. However, the preparation of a traditional calibration curve (MSCC) is labor-intensive and error-prone. Here, a sensitive and robust LC-MS/MS method for quantifying 10 major food allergens was developed and validated, where the one-sample multipoint external calibration curve (OSCC) was employed instead of MSCC. By employing the multiple isotopologue reaction monitoring (MIRM) technique with only one spiked level in the blank, OSCC can be effectively established. Results demonstrate that the proposed method exhibits excellent performance in selectivity, sensitivity, accuracy, and precision, comparable to that of the traditional MSCC. Additionally, this strategy allows for isotope sample dilution by monitoring the less abundant MIRM channel. Moreover, the developed method was successfully applied to investigate the contamination of 10 food allergens in commercial food products. With its high throughput and robustness, the MIRM-OSCC-LC-MS/MS methodology has many potential applications, especially in the MS-based protein quantification analysis.
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  • 文章类型: Journal Article
    心理测量学在历史上是建立在个体差异的研究。因此,定量效度和可靠性等常见指标要求心理变量中的人与人之间的差异有意义。实验心理学,相比之下,处理处理之间的差异,和实验往往努力使组内的人的差异最小化。在这篇文章中,我问是否以及如何在实验心理学中进行心理测量评估。一种常用的策略是在治疗效果中利用人与人之间的差异。使用模拟数据,我表明,当人与人之间的方差较低时,这种方法可能会产生误导,面对方法的差异。我认为这种情况在实验心理学中很常见,因为较低的人与人之间的差异是可取的,并且因为方法差异在实验设置中并不比人与人之间差异的任何其他来源更有问题。通过将效度和信度与心理学之外的测量科学中的相应概念相关联,我展示了基于实验的校准如何用于比较实验心理学中不同测量方法的心理测量质量。
    Psychometrics is historically grounded in the study of individual differences. Consequently, common metrics such as quantitative validity and reliability require between-person variance in a psychological variable to be meaningful. Experimental psychology, in contrast, deals with variance between treatments, and experiments often strive to minimise within-group person variance. In this article, I ask whether and how psychometric evaluation can be performed in experimental psychology. A commonly used strategy is to harness between-person variance in the treatment effect. Using simulated data, I show that this approach can be misleading when between-person variance is low, and in the face of methods variance. I argue that this situation is common in experimental psychology, because low between-person variance is desirable, and because methods variance is no more problematic in experimental settings than any other source of between-person variance. By relating validity and reliability with the corresponding concepts in measurement science outside psychology, I show how experiment-based calibration can serve to compare the psychometric quality of different measurement methods in experimental psychology.
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  • 文章类型: Journal Article
    对于美国食品和药物管理局(FDA)的霉菌毒素计划,认证参考材料(CRM)的理想应用主要是用于验证食品中霉菌毒素的测定方法,并建立由此类验证方法产生的测量结果的计量可追溯性。ThelatterhasbeenanimportantbutinsuitlyaddressedchallengeduetothelackofappropriateprotocolandCRMs.TakingadvantageoftworecentavailablemycotoxinCRMs,OTAN-1和标准参考材料(SRM)1565,开发了一种协议,用于通过使用两种CRM进行一系列校准操作来系统地检查玉米中曲霉毒素A(OTA)的测量结果的不确定性并建立计量可追溯性。使用OTAN-1和SRM1565进行仪器和方法校准。从校准数据估计OTA值及其标准和扩展(k=2,大约95%置信度)的不确定度并记录。这些结果表明,不确定性的主要来源是样本矩阵,强调认证矩阵参考材料在方法校准中的重要作用。产生的样品中的OTA值(38.5±7.2µg/g;95%置信区间)在计量上可以通过两个CRM使用多实验室验证的液相色谱-质谱FDA药典方法追溯到国际单位制。此外,使用单点校准进行了另一种不确定度估计,导致可比的不确定性。
    For the US Food and Drug Administration\'s (FDA) mycotoxin program, the desired application of certified reference materials (CRMs) is primarily for validating methods for the determination of mycotoxins in foods and establishing metrological traceability of measurement results generated by such validated methods. The latter has been an important but insufficiently addressed challenge due to the lack of appropriate protocols and CRMs. Taking advantage of two recently available mycotoxin CRMs, OTAN-1 and Standard Reference Material (SRM) 1565, a protocol was developed for systematically examining uncertainty and establishing metrological traceability of measurement results of ochratoxin A (OTA) in corn through a series of calibration operations using the two CRMs. Instrument and method calibrations were performed using OTAN-1 and SRM 1565. The OTA value and its standard and expanded (k = 2, approximately 95% confidence) uncertainties were estimated from the calibration data and documented. These results demonstrate that the major contributing source of uncertainty is the sample matrix, highlighting the important role of the certified matrix reference material in method calibration. The value of OTA (38.5 ± 7.2 µg/g; 95% confidence interval) in the incurred sample was metrologically traceable to the International System of Units through two CRMs using the multi-laboratory validated liquid chromatography-mass spectrometry FDA compendial method. In addition, an alternative estimation of uncertainty was conducted using a one-point calibration, resulting in comparable uncertainty.
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  • 文章类型: Journal Article
    分析复杂基质中的低水平有机污染物对于监测全球食品安全至关重要。然而,平衡样品通量与复杂的实验设计和/或样品清理以最好地减少基体效应是一个持续的挑战。存在多种策略来减轻这些影响,基于内标的方法,如同位素稀释质谱(IDMS)是最有利的。这里,通过液相色谱-质谱(LC-MS)研究了多种内部校准策略,以定量小麦样品中的曲霉毒素A(OTA)。基于内标的定量方法,如单一(ID1MS),double(ID2MS),和五重(ID5MS)同位素稀释质谱,以及外部标准校准,进行了探索和比较。面粉中OTA的认证参考材料(CRM),MYCO-1用于评估每种方法的准确性。外部校准产生的结果比MYCO-1的认证值低18-38%,这主要是由于基质抑制作用。同时,与ID1MS相比,通过外部校准定量时,小麦样品获得的OTA质量分数始终较低,ID2MS,ID5MS所有同位素稀释方法产生的结果均在MYCO-1的预期范围内(3.17-4.93µg/kg),验证其准确性。然而,与ID2MS和ID5MS相比,从ID1MS获得的结果观察到OTA质量分数平均降低6%。经过审查,这些差异归因于同位素标记的内标[13C6]-OTA用于ID1MS的同位素富集偏差,OTAL-1CRM。说明了每种同位素方法的优点和局限性。
    Analysis of low-level organic contaminants in complex matrices is essential for monitoring global food safety. However, balancing sample throughput with complex experimental designs and/or sample clean-up to best reduce matrix effects is a constant challenge. Multiple strategies exist to mitigate these effects, with internal standard-based methods such as isotope dilution mass spectrometry (IDMS) being the most advantageous. Here, multiple internal calibration strategies were investigated for the quantification of ochratoxin A (OTA) in wheat samples by liquid chromatography-mass spectrometry (LC-MS). Internal standard-based quantitation methods such as single (ID1MS), double (ID2MS), and quintuple (ID5MS) isotope dilution mass spectrometry, as well as external standard calibration, were explored and compared. A certified reference material (CRM) of OTA in flour, MYCO-1, was used to evaluate the accuracy of each method. External calibration generated results 18-38% lower than the certified value for MYCO-1, largely due to matrix suppression effects. Concurrently, consistently lower OTA mass fractions were obtained for the wheat samples upon quantitation by external calibration as opposed to ID1MS, ID2MS, and ID5MS. All isotope dilution methods produced results that fell within the expected range for MYCO-1 (3.17-4.93 µg/kg), validating their accuracy. However, an average 6% decrease in the OTA mass fraction was observed from results obtained by ID1MS compared to those by ID2MS and ID5MS. Upon scrutiny, these differences were attributed to an isotopic enrichment bias in the isotopically labelled internal standard [13C6]-OTA that was used for ID1MS, the OTAL-1 CRM. The advantages and limitations of each isotopic method are illustrated.
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  • 文章类型: Journal Article
    过程分析技术(PAT)在后期药物产品开发中通常用于实时过程监控,过程控制,和实时发布测试。在早期研发(R&D)中,PAT的使用是有限的,因为制造规模相对较小,并且经常变化,并且每年仅生产少量批次。然而,过程理解在早期研发中至关重要,以确定过程和配方边界,因此,PAT应用在早期研发中特别有用。对于口服固体剂型,传统的基于HPLC的含量均匀性(CU)方法,在早期的研发中每个分层采样位置采样3片,通常不足以识别这些制造过程边界和时间分布。这里,我们报告了一种基于多变量模型的筛选CU方法,该方法使用透射拉曼光谱(TRS)数据,对仅16片的相位合适的校准集进行分析.该初始模型用于多个预GMP开发批次,以提供关于共混物均匀性和含量均匀性(CU)的关键信息。在这项工作中,评估了TRS方法的精度;比较了多种光谱预处理方法对测量精度的影响以及在精密实验中减轻光漂白效应的能力。总的来说,基于TRS的CU方法比传统的基于HPLC的方法快得多,从而可以筛选更多的片剂.这种较大数量的分析片剂使得能够识别CU中的过程边界和时间变化,同时提供关于产品质量的适当统计保证。
    Process analytical technology (PAT) in late-stage drug product development is typically used for real-time process monitoring, in-process control, and real-time release testing. In early research and development (R&D), PAT usage is limited as the manufacturing scale is relatively small with frequent changes and only a few batches are produced on an annual basis. However, process understanding is critical at early R&D in order to identify process and formulation boundaries, so PAT applications could be particularly useful in early-stage R&D. For oral solid dosage form, conventional HPLC-based content uniformity (CU) methods with sampling of 3 tablets per stratified sampling location in early R&D are typically not sufficient to identify these manufacturing process boundaries and temporal profile. Here, we report a screening CU method based on a multivariate model using transmission Raman spectroscopy (TRS) data on a phase-appropriate calibration set of only 16 tablets. This initial model was used for multiple pre-GMP development batches to provide critical information about blend uniformity and content uniformity (CU). In this work, the precision of the TRS method was evaluated; multiple spectral preprocessing approaches were compared regarding their effects on measurement precision as well as their ability to mitigate the photo bleaching effects during precision experiments. Overall, the TRS-based CU method was much faster than a traditional HPLC-based method allowing a much larger number of tablets to be screened. This larger number of analyzed tablets enabled the processes boundaries and temporal changes in CU to be identified while providing proper statistical assurance on product quality.
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  • 文章类型: Journal Article
    基于拉曼的分布式温度传感(DTS)是在钻孔换热器(BHE)和地源热泵(GSHP)应用中现场测试和验证传热模型的宝贵工具。然而,温度不确定性在文献中很少报道。在本文中,针对单端DTS配置提出了一种新的校准方法,以及一种消除由于环境空气变化引起的虚拟温度漂移的方法。这些方法是在800m深的同轴BHE中进行分布式热响应测试(DTRT)案例研究的。结果表明,该校准方法和温度漂移校正具有鲁棒性,并给出了足够的结果。温度不确定性从地表附近的约0.4K非线性增加到800m处的约1.7K。温度不确定性由大于200m的深度的校准参数的不确定性主导。本文还提供了在DTRT期间观察到的热特征的见解,包括沿井眼深度的热通量反演和循环下的缓慢温度均质化。
    Raman-based distributed temperature sensing (DTS) is a valuable tool for field testing and validating heat transfer models in borehole heat exchanger (BHE) and ground source heat pump (GSHP) applications. However, temperature uncertainty is rarely reported in the literature. In this paper, a new calibration method was proposed for single-ended DTS configurations, along with a method to remove fictitious temperature drifts due to ambient air variations. The methods were implemented for a distributed thermal response test (DTRT) case study in an 800 m deep coaxial BHE. The results show that the calibration method and temperature drift correction are robust and give adequate results, with a temperature uncertainty increasing non-linearly from about 0.4 K near the surface to about 1.7 K at 800 m. The temperature uncertainty is dominated by the uncertainty in the calibrated parameters for depths larger than 200 m. The paper also offers insights into thermal features observed during the DTRT, including a heat flux inversion along the borehole depth and the slow temperature homogenization under circulation.
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