Mean squared error

均方误差
  • 文章类型: Journal Article
    测量误差的存在在实际中是无法避免的。一个突出的事实是,测量误差的存在会降低估计器的常规特性。提出了一种改进的相关测量误差模型。ShalabhandTsai(CommunStatSimulComput46(7):5566-5593。10.1080/03610918.2016.1165845,2017)相关测量误差模型是建议的修改模型的特定成员。在这篇文章中,我们在修正的相关测量误差模型下,利用辅助信息解决了总体均值的估计问题。我们已经开发了比率和乘积估计器,并研究了它们在简单随机抽样而无需替换(SRSWOR)直至一阶近似的情况下的性质。已经证明,建议的比率和乘积估计器比传统的无偏估计器以及Shalabh和Tsai(CommunStatSimulComput46(7):5566-5593。10.1080/03610918.2016.1165845,2017)在非常现实的情况下的比率和产品估计器。还进行了一项实证研究,以证明推荐的估计量优于其他估计量。
    The existence of measurement errors cannot be avoided in practice. It is a prominent fact that the existence of measurement errors diminishes conventional properties of the estimators. A modified correlated measurement errors model has been proposed. Shalabh and Tsai (Commun Stat Simul Comput 46(7):5566-5593. 10.1080/03610918.2016.1165845, 2017) correlated measurement errors model is a particular member of the suggested modified model. In this article, we have tackled the estimation of population mean utilizing auxiliary information under modified correlated measurement errors model. We have developed ratio and product estimators and studied their properties in case of simple random sampling without replacement (SRSWOR) up to first order of approximation. It has been illustrated that suggested ratio and product estimators are more efficient than the conventional unbiased estimator as well as Shalabh and Tsai (Commun Stat Simul Comput 46(7):5566-5593. 10.1080/03610918.2016.1165845, 2017) ratio and product estimators under very realistic situations. An empirical study has also been performed to demonstrate the merits of the recommended estimators over other estimators.
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  • 文章类型: Journal Article
    我们的研究探索了中性统计学,经典和模糊统计的扩展,解决数据不确定性的挑战。通过利用辅助变量的精确测量,我们可以得出未知人口中位数的精确估计。本研究中引入的估计器对于分析不清楚的,模糊的数据或在中性领域内。与产生单值结果的传统方法不同,我们的估计量产生范围,表明人口参数可能在哪里。我们在一阶近似框架内提出了建议的广义估计器的偏差和均方误差。通过实际数据应用程序和模拟数据集证明了这些拟议的中性估计器的实用性和效率。
    Our study explores neutrosophic statistics, an extension of classical and fuzzy statistics, to address the challenges of data uncertainty. By leveraging accurate measurements of an auxiliary variable, we can derive precise estimates for the unknown population median. The estimators introduced in this research are particularly useful for analysing unclear, vague data or within the neutrosophic realm. Unlike traditional methods that yield single-valued outcomes, our estimators produce ranges, suggesting where the population parameter is likely to be. We present the suggested generalised estimator\'s bias and mean square error within a first-order approximation framework. The practicality and efficiency of these proposed neutrosophic estimators are demonstrated through real-world data applications and the simulated data set.
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  • 文章类型: Journal Article
    估计未知人口的中位数,一些研究人员已经开发了有效的估计器,但是这些估计器无法在存在异常值的情况下提供有效的结果。从这个角度来看,目前的工作建议在异常值/极端观察的情况下,在简单随机抽样的情况下,使用增强的稳健估计器类来估计人口中位数。建议的估计量是一个双变量辅助信息和稳健度量的混合,具有十分位数均值的线性组合,三均值和霍奇斯·莱曼估计。根据偏差和均方误差评估与改进的稳健估计器类别相关的数学特性。此外,通过考虑两个具有离群值的真实数据集来检查我们建议的估计器与已经可用的估计器相比的潜力.此外,在这方面还增加了一项模拟研究。从理论和数值发现来看,据观察,与竞争对手相比,我们新建议的估计量表现优异。
    To estimate the unknown population median, several researchers have developed efficient estimators but these estimators are unable to provide efficient results in the existence of outliers. Keeping this point in view, the present work suggests enhanced class of robust estimators to estimate population median under simple random sampling in case of outliers/extreme observations. The suggested estimators are a mixture of bivariate auxiliary information and robust measures with the linear combination of deciles mean, tri-mean and Hodges Lehmann estimator. Mathematical properties associated with the improved class of robust estimators are evaluated in terms of bias and mean squared error. Moreover, the potentiality of our suggested estimators as compared to already available estimators is checked by considering two real-life data sets with outlier(s). In addition, a simulation study is also added in this regard. From theoretical and numerical findings, it is observed that our newly suggested estimators outperforms as compared to its competitors.
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  • 文章类型: Journal Article
    大多数科学领域可用的统计数据分析通常记录有测量误差。通过忽略测量误差对这些统计数据进行建模,导致分布参数的估计,其使用在拟合优度方面没有达到足够的准确性。在可靠性标准中,其中一个重要问题是危险率函数。它促使我们在存在正态分布或逻辑分布产生的测量误差的情况下研究危险率标准。现在,在使用局部时间多项式估计方法为密度函数提供估计器的同时,根据15%或30%的污染程度估算风险率函数。最后,我们给出了数值分析。
    Statistical data analysis available in most scientific fields is often recorded with measurement error. The modeling of these statistical data by ignoring the measurement errors, leads to estimators of the parameters of the distributions, whose use does not achieve sufficient accuracy in the goodness of fit. In reliability criteria, one of the important issues is hazard rate function. It prompted us to investigate the hazard rate criterion in the presence of measurement error generated from the normal or logistic distribution. Now, while providing the estimator for the density function using local time polynomial estimator methods, the risk rate function is estimated according to the contamination degree of 15 or 30%. Finally, we present the numerical analysis.
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  • 文章类型: Journal Article
    在这篇文章中,在基本概率抽样设计下,利用辅助信息,为敏感研究变量的总体均值估计提供了两个ln型估计。使用Taylor和log级数来推导出均方误差和偏差的表达式,直至一阶。通过使用与补充变量相关联的常规参数来获得所提出的估计器的改进类别,以获得精确的估计。使用均方误差的理论方程,已将估算器与通常的平均值和比率估算器进行了数学比较。使用通过R软件生成的四个人工总体,使用均值向量和方差-协方差矩阵的不同选择,对所提出的估计器的实现进行了模拟研究。提出的ln型估计器的演示是通过实际数据应用实现的。
    In this article, we offered two ln-type estimators for the population mean estimation of a sensitive study variable by using the auxiliary information under the design of basic probability sampling. The Taylor and log series were used to derive the expressions of mean square error and bias up to the first order. Improved classes of proposed estimators are obtained by using conventional parameters associated with the supplementary variable to obtained precise estimates. Mathematical comparisons of the estimators have been made with the usual mean and ratio estimators using theoretical equations of mean square error. A simulation study is conducted for the evaluation of proposed estimator\'s implementation using four artificial populations generated through R-software with different choices of mean vectors and variance-covariance matrices. The demonstration of proposed ln-type estimators was implemented through the real data application.
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  • 文章类型: Journal Article
    孟德尔随机化(MR)是一种统计方法,利用遗传变异作为工具变量(IVs)来研究风险因素与结果之间的因果关系。尽管近年来MR由于能够分析来自全基因组关联研究(GWAS)的汇总统计数据而受到欢迎,它需要大量的单核苷酸多态性(SNP)作为IVs,以确保检测因果效应的足够能力。不幸的是,许多性状的复杂遗传遗传性可导致使用无效的IVs,直接或通过未观察到的混淆因素影响危险因素和结果.这可能导致有偏差和不精确的估计,如较大的均方误差(MSE)所反映。在这项研究中,我们专注于广泛使用的两阶段最小二乘(2SLS)方法,并推导了使用无效IV估计因果效应时的偏差和MSE公式。使用这些公式,我们确定了2SLS估计无偏的条件,并揭示了独立或相关的多效性效应如何影响2SLS估计的准确性和准确性。我们通过广泛的模拟研究验证了这些公式,并证明了这些公式在MR研究中的应用,以评估腰臀比对各种睡眠方式的因果影响。我们的结果可以帮助设计未来的MR研究,并作为评估更复杂的MR方法的基准。
    Mendelian randomization (MR) is a statistical method that utilizes genetic variants as instrumental variables (IVs) to investigate causal relationships between risk factors and outcomes. Although MR has gained popularity in recent years due to its ability to analyze summary statistics from genome-wide association studies (GWAS), it requires a substantial number of single nucleotide polymorphisms (SNPs) as IVs to ensure sufficient power for detecting causal effects. Unfortunately, the complex genetic heritability of many traits can lead to the use of invalid IVs that affect both the risk factor and the outcome directly or through an unobserved confounder. This can result in biased and imprecise estimates, as reflected by a larger mean squared error (MSE). In this study, we focus on the widely used two-stage least squares (2SLS) method and derive formulas for its bias and MSE when estimating causal effects using invalid IVs. Using those formulas, we identify conditions under which the 2SLS estimate is unbiased and reveal how the independent or correlated pleiotropic effects influence the accuracy and precision of the 2SLS estimate. We validate these formulas through extensive simulation studies and demonstrate the application of those formulas in an MR study to evaluate the causal effect of the waist-to-hip ratio on various sleeping patterns. Our results can aid in designing future MR studies and serve as benchmarks for assessing more sophisticated MR methods.
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  • 文章类型: Journal Article
    联合循环发电厂(CCPP)是一种有效的发电方法,由于其热效率高,低油耗,和低温室气体排放。然而,在不了解发电能力的情况下,投资数百万美元建造发电厂似乎没有成效。在AI的帮助下,我们试图消除这个难题。本研究的重点是使用反向传播神经网络(BPNN)预测747MW联合循环发电厂(CCPP)产生的功率,并将其结果与CCPP的实际数据进行比较。BPNN是一种基于回归的预测技术,在本研究中用于开发预测模型并使用以下输入特征对其进行训练:环境温度,环境压力,燃气轮机1中的燃料质量流量和燃气轮机2中的燃料质量流量。发现在隐藏层中具有10个神经元的预测模型在均方误差(MSE)值的情况下最有效,对于验证数据集,0.0063237。CCPP还通过热力学模型进行了分析,使用EES开发。进行了详细的能量分析,并将结果与预测和实际数据进行了比较。研究发现,实际的热效率和总发电量,预测,模拟模型为27.541%和667.32MW,28.238%和683.48兆瓦和28.201%和683.16兆瓦,分别。进一步进行了参数研究,以研究运行参数对功率输出的重要性,并得出结论,整个燃气轮机的温度对CCPP的性能具有重大影响。最后,甲烷被3种不同的燃料取代,一个接一个,并对每种燃料的影响进行了热力学研究。发现燃料的低热值(LHV)是实现更高功率输出的重要参数。从这项研究工作中可以总结出,预测模型确实具有准确性,并且这种数据科学技术可以用作广泛的热力学计算的替代品。
    Combined Cycle Power Plants (CCPP) are an effective method for Power generation due to their high thermal efficiency, low fuel consumption, and low greenhouse emissions. However, investing millions into building a power plant without knowledge of the power generation capacity seems unproductive. With the help of AI, we have tried to eliminate this conundrum. The present study focuses on the prediction of power produced by a 747 MW Combined Cycle Power Plant (CCPP) using a Back Propagation Neural Network (BPNN) and compares its results with the actual data from CCPP. BPNN is a regression-based prediction technique that is utilized in this study to develop a predictive model and train it using the following input features: Ambient Temperature, Ambient Pressure, Mass Flow rate of fuel in Gas Turbine 1, and Mass Flow rate of fuel in Gas Turbine 2. The Predictive Model with 10 neurons in the hidden layer was found to be most effective with Mean Squared Error (MSE) value, for the validation dataset, of 0.0063237. CCPP is also analyzed through a thermodynamic model, developed using EES. A detailed energy analysis is carried out and the results were compared with predicted and actual data. It was found that the thermal efficiency and total power generation of actual, predicted, and simulated models were 27.541% & 667.32 MW, 28.238% & 683.48 MW and 28.201% & 683.16 MW, respectively. A parametric study was further carried out to investigate the significance of operating parameters on power output and it was concluded that the temperatures across the Gas turbines have a significant impact on the performance of CCPP. Finally, Methane was replaced by 3 different fuels, one by one, and the effect of each fuel was investigated thermodynamically. It was found that the Lower Heating Value (LHV) of fuel was an important parameter in achieving a higher power output. It can be summarized from this research work that predictive models do have accuracy and such data science techniques can be used as a substitute for extensive thermodynamic calculations.
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  • 文章类型: Journal Article
    UNASSIGNED:本文提出了一种基于深度学习(DL)的方法,称为TextureWGAN。它旨在保留图像纹理,同时保持计算机断层扫描(CT)反问题的高像素保真度。后处理算法的过度平滑图像已经是医学成像行业中众所周知的问题。因此,我们的方法试图在不影响像素保真度的情况下解决过度平滑问题。
    未授权:TextureWGAN从WassersteinGAN(WGAN)延伸而来。WGAN可以创建看起来像真实图像的图像。WGAN的这一方面有助于保持图像纹理。然而,来自WGAN的输出图像与对应的地面实况图像不相关。为了解决这个问题,我们将多任务正则化(MTR)引入WGAN框架,使生成的图像与相应的地面实况图像高度相关,以便TextureWGAN可以实现高水平的像素保真度。MTR能够使用多个目标函数。在这项研究中,我们采用均方误差(MSE)损失来保持像素保真度。我们还使用感知损失来改善结果图像的外观和感觉。此外,MTR中的正则化参数与生成器网络权重一起进行训练,以最大化TextureWGAN生成器的性能。
    UNASSIGNED:除了超分辨率和图像去噪应用外,还在CT图像重建应用中评估了所提出的方法。我们进行了广泛的定性和定量评估。我们使用PSNR和SSIM进行像素保真度分析,并对图像纹理进行一阶和二阶统计纹理分析。结果表明,与传统CNN和非局部均值滤波器(NLM)等其他众所周知的方法相比,TextureWGAN在保持图像纹理方面更有效。此外,我们证明,与CNN和NLM相比,TextureWGAN可以实现具有竞争力的像素保真度性能。具有MSE损失的CNN可以达到高水平的像素保真度,但它经常损害图像纹理。
    UNASSIGNED:TextureWGAN可以在保持像素保真度的同时保留图像纹理。MTR不仅有助于稳定TextureWGAN的发电机训练,而且还可以最大程度地提高发电机的性能。
    UNASSIGNED: This paper presents a deep learning (DL) based method called TextureWGAN. It is designed to preserve image texture while maintaining high pixel fidelity for computed tomography (CT) inverse problems. Over-smoothed images by postprocessing algorithms have been a well-known problem in the medical imaging industry. Therefore, our method tries to solve the over-smoothing problem without compromising pixel fidelity.
    UNASSIGNED: The TextureWGAN extends from Wasserstein GAN (WGAN). The WGAN can create an image that looks like a genuine image. This aspect of the WGAN helps preserve image texture. However, an output image from the WGAN is not correlated to the corresponding ground truth image. To solve this problem, we introduce the multitask regularizer (MTR) to the WGAN framework to make a generated image highly correlated to the corresponding ground truth image so that the TextureWGAN can achieve high-level pixel fidelity. The MTR is capable of using multiple objective functions. In this research, we adopt a mean squared error (MSE) loss to maintain pixel fidelity. We also use a perception loss to improve the look and feel of result images. Furthermore, the regularization parameters in the MTR are trained along with generator network weights to maximize the performance of the TextureWGAN generator.
    UNASSIGNED: The proposed method was evaluated in CT image reconstruction applications in addition to super-resolution and image-denoising applications. We conducted extensive qualitative and quantitative evaluations. We used PSNR and SSIM for pixel fidelity analysis and the first-order and the second-order statistical texture analysis for image texture. The results show that the TextureWGAN is more effective in preserving image texture compared with other well-known methods such as the conventional CNN and nonlocal mean filter (NLM). In addition, we demonstrate that TextureWGAN can achieve competitive pixel fidelity performance compared with CNN and NLM. The CNN with MSE loss can attain high-level pixel fidelity, but it often damages image texture.
    UNASSIGNED: TextureWGAN can preserve image texture while maintaining pixel fidelity. The MTR is not only helpful to stabilize the TextureWGAN\'s generator training but also maximizes the generator performance.
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  • 文章类型: Journal Article
    临床研究中面临的一个常见问题是估计k(≥2)种可用治疗中最有效(例如具有最大平均)治疗的效果。根据与k种处理相对应的一些统计量的数值来判断最有效的处理。针对此类问题的适当设计是所谓的“丢弃失败者设计(DLD)”。我们考虑两种治疗方法,其效果由具有不同未知均值和共同已知方差的独立高斯分布描述。为了选择更有效的治疗方法,将两种治疗各自独立地给予n1个受试者,并且选择对应于较大样本平均值的治疗。为了研究判定的更有效治疗的效果(即估计其平均值),我们考虑两阶段DLD,其中n2受试者在设计的第二阶段被认为是更有效的治疗.我们获得了一些可容许性和最小性结果,以估计所判定的更有效治疗的平均效果。最大似然估计器显示为minimax且可允许。我们证明了所选治疗均值的均匀最小方差条件无偏估计器(UMVCUE)是不可接受的,并获得了改进的估计器。在这个过程中,我们还得出了任意位置和置换等变估计器不可接受性的充分条件,并在某些情况下提供了主导估计器,在满足这个充分条件的情况下。通过仿真研究比较了各种竞争估计器的均方误差和偏差性能。为了说明的目的,还提供了真实的数据示例。
    A common problem faced in clinical studies is that of estimating the effect of the most effective (e.g. the one having the largest mean) treatment among k(≥2) available treatments. The most effective treatment is adjudged based on numerical values of some statistic corresponding to the k treatments. A proper design for such problems is the so-called \"Drop-the-Losers Design (DLD)\". We consider two treatments whose effects are described by independent Gaussian distributions having different unknown means and a common known variance. To select the more effective treatment, the two treatments are independently administered to n1 subjects each and the treatment corresponding to the larger sample mean is selected. To study the effect of the adjudged more effective treatment (i.e. estimating its mean), we consider the two-stage DLD in which n2 subjects are further administered the adjudged more effective treatment in the second stage of the design. We obtain some admissibility and minimaxity results for estimating the mean effect of the adjudged more effective treatment. The maximum likelihood estimator is shown to be minimax and admissible. We show that the uniformly minimum variance conditionally unbiased estimator (UMVCUE) of the selected treatment mean is inadmissible and obtain an improved estimator. In this process, we also derive a sufficient condition for inadmissibility of an arbitrary location and permutation equivariant estimator and provide dominating estimators in cases, where this sufficient condition is satisfied. The mean squared error and the bias performances of various competing estimators are compared via a simulation study. A real data example is also provided for illustration purpose.
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  • 文章类型: Journal Article
    野火在最近几十年发生了变化。灾难性的野火使得有必要在国家范围内建立准确的预测模型来组织消防资源。在地中海国家,野火的数量相当多,但主要集中在夏季。由于季节性,有些地区的火灾数量在某些月份为零,而在其他地区则过度分散。零膨胀负二项混合模型适用于这种类型的数据,因为它们可以描述解释火灾数量及其不发生的模式,并且还提供有用的预测工具。除了基于模型的预测,参数自举方法用于估计均方误差和构造预测区间。统计方法和开发的软件用于建模和预测2002年至2015年间西班牙各省和月份的野火数量。
    Wildfires have changed in recent decades. The catastrophic wildfires make it necessary to have accurate predictive models on a country scale to organize firefighting resources. In Mediterranean countries, the number of wildfires is quite high but they are mainly concentrated around summer months. Because of seasonality, there are territories where the number of fires is zero in some months and is overdispersed in others. Zero-inflated negative binomial mixed models are adapted to this type of data because they can describe patterns that explain both number of fires and their non-occurrence and also provide useful prediction tools. In addition to model-based predictions, a parametric bootstrap method is applied for estimating mean squared errors and constructing prediction intervals. The statistical methodology and developed software are applied to model and to predict number of wildfires in Spain between 2002 and 2015 by provinces and months.
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