linear models

线性模型
  • 文章类型: Journal Article
    荟萃分析是综合多项研究结果的有力工具。正态-正态随机效应模型被广泛用于解释研究之间的异质性。然而,稀疏数据的荟萃分析,当二进制或计数结果的事件发生率较低时,可能会出现这种情况,由于研究内模型中的正态逼近可能不好,因此在推理的准确性和稳定性方面对正态-正态随机效应模型提出了挑战。为了减少数据稀疏性引起的偏差,广义线性混合模型可以通过用精确模型代替近似正常的研究内模型来使用。发表偏倚是荟萃分析中最严重的威胁之一。对于正常-正常随机效应模型,可以使用几种定量敏感性分析方法来评估选择性出版物的潜在影响。我们通过将基于似然的敏感性分析与Copas的$t$统计量选择函数扩展到几个广义线性混合效应模型,提出了一种敏感性分析方法。通过将我们提出的方法应用于几个现实世界的荟萃分析和仿真研究,该方法被证明优于基于正态-正态模型的基于似然的灵敏度分析。所提出的方法将为解决稀疏数据荟萃分析中的发表偏差提供有用的指导。
    Meta-analysis is a powerful tool to synthesize findings from multiple studies. The normal-normal random-effects model is widely used to account for between-study heterogeneity. However, meta-analyses of sparse data, which may arise when the event rate is low for binary or count outcomes, pose a challenge to the normal-normal random-effects model in the accuracy and stability in inference since the normal approximation in the within-study model may not be good. To reduce bias arising from data sparsity, the generalized linear mixed model can be used by replacing the approximate normal within-study model with an exact model. Publication bias is one of the most serious threats in meta-analysis. Several quantitative sensitivity analysis methods for evaluating the potential impacts of selective publication are available for the normal-normal random-effects model. We propose a sensitivity analysis method by extending the likelihood-based sensitivity analysis with the $t$-statistic selection function of Copas to several generalized linear mixed-effects models. Through applications of our proposed method to several real-world meta-analyses and simulation studies, the proposed method was proven to outperform the likelihood-based sensitivity analysis based on the normal-normal model. The proposed method would give useful guidance to address publication bias in the meta-analysis of sparse data.
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  • 文章类型: Journal Article
    氟化物(F)是人体必需的微量元素,在环境中自然存在。然而,环境中F的缺乏或过量可能导致人类健康问题。土壤中F的假总含量通常与植物中的F含量没有直接关系。相反,植物中的F含量往往与土壤中的生物可利用性F具有更大的相关性。在大规模的土壤调查中,通常只测量土壤的伪元素含量,这对于制定农业分区计划可能不太可靠。不同植物从土壤中积累F的能力存在显著差异。此外,由于不同植物物种之间土壤元素吸收机制的差异,当一个地区种植多种作物时,通常有必要研究每种作物的元素吸收机制。为了解决这些问题,在这项研究中,基于1:50,000土壤地球化学调查数据,我们研究了影响不同作物F生物累积系数的因素。使用随机森林算法,四个指标-生物可利用性P,生物可利用锌,可浸出Pb,从29个参数中选择Sr-来预测作物中的F含量,以替代土壤中的生物可利用性F。与多元线性回归(MLR)模型相比,随机森林(RF)模型提供了更准确和可靠的预测作物中的氟化物含量,射频模型的预测精度提高了约95.23%。此外,虽然偏最小二乘回归(PLSR)模型也比MLR提供了更高的精度,RF模型在预测准确性和鲁棒性方面仍优于PLSR。此外,它最大限度地利用了现有的地球化学调查数据,首次实现了跨物种研究,并避免了对同一地区不同类型农产品的重复评估。在这次调查中,我们选择了青海省的西宁-乐都地区,中国,以研究区域为研究区域,采用随机森林模型预测土壤中作物F含量,为作物生产提供新的方法框架,有效提高农业质量和效率。
    Fluoride (F) is a trace element that is essential to the human body and occurs naturally in the environment. However, a deficiency or excess of F in the environment can potentially lead to human health issues. The pseudototal amount of F in soil often does not correlate directly with the F content in plants. Instead, the F content within plants tends to have a greater correlation with the bioavailable F in soils. In large-scale soil surveys, only the pseudototal elemental content of soils is typically measured, which may not be highly reliable for developing agricultural zoning plans. There are significant variations in the ability of different plants to accumulate F from soil. Additionally, due to variations in soil elemental absorption mechanisms among different plant species, when multiple crops are grown in an area, it is typically necessary to study the elemental absorption mechanisms of each crop. To address these issues, in this study, we examined the factors influencing F bioaccumulation coefficients in different crops based on 1:50,000 soil geochemical survey data. Using the random forest algorithm, four indicators-bioavailable P, bioavailable Zn, leachable Pb, and Sr-were selected from among 29 parameters to predict the F content within crops to replace bioavailable F in the soil. Compared with the multivariate linear regression (MLR) model, the random forest (RF) model provided more accurate and reliable predictions of the fluoride content in crops, with the RF model\'s prediction accuracy improving by approximately 95.23%. Additionally, while the partial least squares regression (PLSR) model also offered improved accuracy over MLR, the RF model still outperformed PLSR in terms of prediction accuracy and robustness. Additionally, it maximized the utilization of existing geochemical survey data, enabling cross-species studies for the first time and avoiding redundant evaluations of different types of agricultural products in the same region. In this investigation, we selected the Xining-Ledu region of Qinghai Province, China, as the study area and employed a random forest model to predict the crop F content in soils, providing a new methodological framework for crop production that effectively enhances agricultural quality and efficiency.
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  • 文章类型: Journal Article
    目前,世界各地越来越多的湖泊正在经历蓝藻水华的爆发,而高精度快速监测水体中藻类的空间分布是一项重要任务。遥感技术是监测水体藻类的有效手段之一。研究表明,浮藻指数(FAI)在监测蓝藻水华方面优于标准化差异植被指数(NDVI)和增强植被指数(EVI)等方法。然而,与NDVI方法相比,FAI方法难以确定阈值,如何选择分类准确率最高的阈值具有挑战性。在这项研究中,选择FAI线性拟合模型(FAI-L)来解决FAI阈值难以确定的问题。创新结合FAI指数和NDVI指数,并使用NDVI指数找到FAI指数的阈值。为了分析FAI-L提取蓝藻水华的适用性,本文选择了多时相Landsat8,HJ-1B,和Sentinel-2遥感图像作为数据源,并以中国的巢湖和太湖为研究区,提取蓝藻水华。结果表明:(1)FAI-L法提取蓝藻水华的准确度普遍高于NDVI和FAI法。在不同的数据来源和不同的研究领域下,FAI-L法提取蓝藻水华的平均准确率为95.13%,分别比NDVI和FAI高出6.98%和18.43%。(2)FAI-L法提取蓝藻水华的平均准确率在84.09~99.03%之间,标准偏差为4.04,具有高度的稳定性和适用性。(3)对于同步的多源图像数据,FAI-L法提取蓝藻水华的平均准确度最高,95.93%,比NDVI和FAI方法高6.77%和13.26%,分别。在本文中,发现FAI-L法提取蓝藻水华具有较高的准确性和稳定性,它可以很好地提取蓝藻水华的空间分布,为蓝藻水华监测提供了一种新的方法。
    Currently, more and more lakes around the world are experiencing outbreaks of cyanobacterial blooms, and high-precision and rapid monitoring of the spatial distribution of algae in water bodies is an important task. Remote sensing technology is one of the effective means for monitoring algae in water bodies. Studies have shown that the Floating Algae Index (FAI) is superior to methods such as the Standardized Differential Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) in monitoring cyanobacterial blooms. However, compared to the NDVI method, the FAI method has difficulty in determining the threshold, and how to choose the threshold with the highest classification accuracy is challenging. In this study, FAI linear fitting model (FAI-L) is selected to solve the problem that FAI threshold is difficult to determine. Innovatively combine FAI index and NDVI index, and use NDVI index to find the threshold of FAI index. In order to analyze the applicability of FAI-L to extract cyanobacterial blooms, this paper selected multi-temporal Landsat8, HJ-1B, and Sentinel-2 remote sensing images as data sources, and took Chaohu Lake and Taihu Lake in China as research areas to extract cyanobacterial blooms. The results show that (1) the accuracy of extracting cyanobacterial bloom by FAI-L method is generally higher than that by NDVI and FAI. Under different data sources and different research areas, the average accuracy of extracting cyanobacterial blooms by FAI-L method is 95.13%, which is 6.98% and 18.43% higher than that by NDVI and FAI respectively. (2) The average accuracy of FAI-L method for extracting cyanobacterial blooms varies from 84.09 to 99.03%, with a standard deviation of 4.04, which is highly stable and applicable. (3) For simultaneous multi-source image data, the FAI-L method has the highest average accuracy in extracting cyanobacterial blooms, at 95.93%, which is 6.77% and 13.26% higher than NDVI and FAI methods, respectively. In this paper, it is found that FAI-L method shows high accuracy and stability in extracting cyanobacterial blooms, and it can extract the spatial distribution of cyanobacterial blooms well, which can provide a new method for monitoring cyanobacterial blooms.
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  • 文章类型: Journal Article
    全身免疫炎症指数(SII)是一种新型的综合性炎症标志物。炎症与肺功能受损有关。我们旨在探讨SII与肺功能之间的可能关系,以检查SII在预测肺功能下降方面的潜力。
    使用2007年至2012年NHANES的数据进行了横断面调查。采用多元线性回归模型分析SII与肺功能的线性关系。敏感性分析,亚组分析,和相互作用测试被用来检查不同人群之间这种关系的稳健性。拟合平滑曲线和阈值效应分析用于描述非线性关系。
    本研究共纳入10,125例患者。在调整所有协变量后,多元线性回归模型分析表明,高Log2-SII水平与FVC降低显著相关(β,-23.4061;95%CI,-42.2805-4.5317),FEV1(β,-46.7730;95%CI,-63.3371--30.2089),FEV1%(β,-0.7923;95%CI,-1.1635--0.4211),FEV1/FVC(β,-0.6366;95%CI,-0.8328--0.4404)和PEF(β,-121.4468;95%CI,-164.1939--78.6998)。在趋势检验和分层分析中,Log2-SII与肺功能指标之间的负相关保持稳定。Log2-SII与FVC倒U型关系,FEV1,FEV1%,和PEF被观察到,FEV1/FVC与Log2-SII呈负相关。Log2-SII与FVC之间非线性关系的截止值,FEV1,FEV1%,PEF分别为8.3736、8.0688、8.3745和8.5255。当SII超过临界值时,肺功能明显下降。
    这项研究发现SII与肺功能指标之间存在密切的相关性。这项研究调查了总体人群中肺功能开始下降时的SII阈值。SII可能成为预测肺功能下降的有希望的血清学指标。然而,需要进一步的前瞻性研究来确定这两个因素之间的因果关系。
    UNASSIGNED: Systemic immune-inflammation index (SII) is a novel comprehensive inflammatory marker. Inflammation is associated with impaired lung function. We aimed to explore the possible relationship between SII and lung function to examine the potential of SII in predicting lung function decline.
    UNASSIGNED: A cross-sectional survey was conducted using the data of the NHANES from 2007 to 2012. Multiple linear regression models were used to analyze the linear relationship between SII and pulmonary functions. Sensitivity analyses, subgroup analyses, and interaction tests were used to examine the robustness of this relationship across populations. Fitted smooth curves and threshold effect analysis were used to describe the nonlinear relationships.
    UNASSIGNED: A total of 10,125 patients were included in this study. After adjusting for all covariates, multiple linear regression model analysis showed that high Log2-SII level was significantly associated with decreased FVC(β, -23.4061; 95% CI, -42.2805- -4.5317), FEV1(β, -46.7730; 95% CI, -63.3371- -30.2089), FEV1%(β, -0.7923; 95% CI, -1.1635- -0.4211), FEV1/FVC(β, -0.6366; 95% CI, -0.8328- -0.4404) and PEF(β, -121.4468; 95% CI,-164.1939- -78.6998). The negative correlation between Log2-SII and pulmonary function indexes remained stable in trend test and stratified analysis. Inverted U-shaped relationships between Log2-SII and FVC, FEV1, FEV1%, and PEF were observed, while a negative linear correlation existed between FEV1/FVC and Log2-SII. The cutoff values of the nonlinear relationship between Log2-SII and FVC, FEV1, FEV1%, PEF were 8.3736, 8.0688, 8.3745, and 8.5255, respectively. When SII exceeded the critical value, the lung function decreased significantly.
    UNASSIGNED: This study found a close correlation between SII and pulmonary function indicators. This study investigated the SII threshold when lung functions began to decline in the overall population. SII may become a promising serological indicator for predicting lung function decline. However, prospective studies were needed further to establish the causal relationship between these two factors.
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  • 文章类型: Journal Article
    在米拉贝隆(MIR)合成中,在MIR的合成过程中获得了N-亚硝基米拉贝隆(NNM);在酸性条件下使用水进行反应。亚硝酸盐来源来自水,并且仲胺源来自MIR,因为它具有仲胺;NNM在MIR的合成过程中作为杂质产生。NNM在MIR中的存在可能会影响其有效性。本研究的目的是建立超高效液相色谱-质谱/质谱(UPLC-MS/MS)方法来鉴定MIR样品中的NNM。NNM分析方法是在AcquityHSST3(100*2.1)mm1.8μm色谱柱上开发的,使用流动相由0.1%甲酸的水溶液(流动相A)和0.1%甲酸的甲醇(流动相B)组成的梯度洗脱。在NNM(m/z426.20→170.00)的分析中使用以MRM模式操作的具有电喷雾电离的质谱仪。提出的UPLC-MS/MS方法显示出良好的线性(0.02至0.72ppm),良好的系统精度(RSD=0.57%),方法精密度好(RSD=0.87%),可接受的精度(94.5-116.5%),NNM的低检测限(0.006ppm)和低定量限(0.02ppm)。所提出的UPLC-MS/MS方法可用于评估NNM杂质存在的MIR样品的质量。
    In the mirabegron (MIR) synthesis, the N-nitroso mirabegron (NNM) is obtained during synthetic process of MIR; water is being used in reaction under acidic condition. Nitrite source is from water, and secondary amine source is from MIR as it has secondary amine; NNM is generated as an impurity during the synthesis of MIR. The presence of NNM in MIR could potentially affect its effectiveness. The purpose of this study was to establish a Ultra-performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS) methodology to identify NNM in MIR samples. The method for NNM analysis was developed on Acquity HSS T3 (100*2.1) mm 1.8 μm column with gradient elution using mobile phase consisted of 0.1% formic acid in water (mobile phase A) and 0.1% formic acid in methanol (mobile phase B). Mass spectrometer with electrospray ionization operated in the MRM mode was used in the analysis of NNM (m/ z 426.20 → 170.00). The UPLC-MS/MS methodology proposed showed a good linearity (0.02 to 0.72 ppm), good system precision (RSD = 0.57%), good method precision (RSD = 0.87%), acceptable accuracy (94.5-116.5%), low detection limit (0.006 ppm) and low quantification limit (0.02 ppm) for NNM. The UPLC-MS/MS methodology proposed can be utilized to assess the quality of MIR sample for the presence of NNM impurity.
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  • 文章类型: Journal Article
    目的:评估人工智能(AI)模型在预测正畸治疗后的软组织和牙槽骨变化中的应用,并将AI模型与常规预测模型的预测性能进行比较。
    方法:收集887例接受正畸治疗的成年患者的1774例侧头颅图。接受正颌手术的患者被排除在外。在每张头影上,使用基于PIPNet的AI检测到78个地标。预测模型由132个预测变量和88个结果变量组成。预测变量是人口统计学(年龄,sex),临床(治疗时间,前磨牙提取),和64个解剖标志的笛卡尔坐标。结果变量是正畸治疗后22个软组织和22个硬组织标志的笛卡尔坐标。AI预测模型基于TabNet深度神经网络。两种常规的统计方法,多元多元线性回归(MMLR)和偏最小二乘回归(PLSR),每个都是为了比较而实施的。比较了两种方法的预测精度。
    结果:总体而言,MMLR显示了最准确的结果,而AI最不准确。人工智能在44个解剖标志中只有5个显示出更好的预测,所有这些都是位于颈部终点下方的软组织标志。
    结论:在预测正畸治疗后的变化时,AI不如常规统计方法有效。然而,AI在预测具有实质性变异性的软组织标志方面具有突出优势。总的来说,结果可能表明需要一种结合传统方法和人工智能方法的混合预测模型。
    OBJECTIVE: To evaluate an artificial intelligence (AI) model in predicting soft tissue and alveolar bone changes following orthodontic treatment and compare the predictive performance of the AI model with conventional prediction models.
    METHODS: A total of 1774 lateral cephalograms of 887 adult patients who had undergone orthodontic treatment were collected. Patients who had orthognathic surgery were excluded. On each cephalogram, 78 landmarks were detected using PIPNet-based AI. Prediction models consisted of 132 predictor variables and 88 outcome variables. Predictor variables were demographics (age, sex), clinical (treatment time, premolar extraction), and Cartesian coordinates of the 64 anatomic landmarks. Outcome variables were Cartesian coordinates of the 22 soft tissue and 22 hard tissue landmarks after orthodontic treatment. The AI prediction model was based on the TabNet deep neural network. Two conventional statistical methods, multivariate multiple linear regression (MMLR) and partial least squares regression (PLSR), were each implemented for comparison. Prediction accuracy among the methods was compared.
    RESULTS: Overall, MMLR demonstrated the most accurate results, while AI was least accurate. AI showed superior predictions in only 5 of the 44 anatomic landmarks, all of which were soft tissue landmarks inferior to menton to the terminal point of the neck.
    CONCLUSIONS: When predicting changes following orthodontic treatment, AI was not as effective as conventional statistical methods. However, AI had an outstanding advantage in predicting soft tissue landmarks with substantial variability. Overall, results may indicate the need for a hybrid prediction model that combines conventional and AI methods.
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  • 文章类型: Journal Article
    目的:与常规预测方法相比,评估人工智能(AI)模型在预测正颌手术结果方面的性能。
    方法:收集705例接受手术-正畸联合治疗的患者的术前和治疗后侧位头颅图。预测器包括254个输入变量,包括术前骨骼和软组织特征,以及正颌手术重新定位的程度。结果是手术后32个软组织标志的64个笛卡尔坐标变量。采用多元多元线性回归(MLR)和多元偏最小二乘算法(PLS)两种线性回归方法建立常规预测模型。基于AI的预测模型基于TabNet深度神经网络。比较了预测精度,并对影响因素进行了分析。
    结果:一般来说,MLR表现出最差的预测性能。在32个软组织地标中,PLS在上唇上方的16个软组织标志中显示出更准确的预测结果,而AI在位于下颌骨和颈部区域下边界的六个地标中表现出色。其余10个地标在AI和PLS预测模型之间没有显着差异。
    结论:AI预测并不总是优于常规方法。两种方法的组合可能更有效地预测正颌手术结果。
    OBJECTIVE: To evaluate the performance of an artificial intelligence (AI) model in predicting orthognathic surgical outcomes compared to conventional prediction methods.
    METHODS: Preoperative and posttreatment lateral cephalograms from 705 patients who underwent combined surgical-orthodontic treatment were collected. Predictors included 254 input variables, including preoperative skeletal and soft-tissue characteristics, as well as the extent of orthognathic surgical repositioning. Outcomes were 64 Cartesian coordinate variables of 32 soft-tissue landmarks after surgery. Conventional prediction models were built applying two linear regression methods: multivariate multiple linear regression (MLR) and multivariate partial least squares algorithm (PLS). The AI-based prediction model was based on the TabNet deep neural network. The prediction accuracy was compared, and the influencing factors were analyzed.
    RESULTS: In general, MLR demonstrated the poorest predictive performance. Among 32 soft-tissue landmarks, PLS showed more accurate prediction results in 16 soft-tissue landmarks above the upper lip, whereas AI outperformed in six landmarks located in the lower border of the mandible and neck area. The remaining 10 landmarks presented no significant difference between AI and PLS prediction models.
    CONCLUSIONS: AI predictions did not always outperform conventional methods. A combination of both methods may be more effective in predicting orthognathic surgical outcomes.
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  • 文章类型: Journal Article
    健康事件的空间聚类分析有助于实现有针对性的干预措施。空间扫描统计是这种分析的最新方法,空间扫描统计的泊松广义线性模型(GLM)方法可用于计数数据,以进行协变量调整。然而,由于数据过度分散,其用于建模的用途有限。最近提出了一种广义线性混合模型(GLMM),用于通过将随机效应结合到模型中其他协变量无法解释的特定于区域的内在变化中来对这种过度分散进行建模。然而,这些随机效应可能表现出地理相关性,这可能导致潜在的空间集群未被发现。要处理计数数据中的过度分散,这项研究旨在评估在开伯尔-普赫图赫瓦省低出生体重的现实世界数据的空间扫描统计中,负二项式-GLM的表现,巴基斯坦,2019.将结果与泊松-GLM和GLMM进行了比较,表明负二项式GLM是存在过度分散数据的空间扫描统计量的理想选择。通过协变量(孕产妇贫血)调整,基于负二项GLM的空间扫描统计量检测到一个覆盖Dir较低区域的重要聚类。没有协变量调整,它检测到两个集群,每个覆盖一个地区。白沙瓦地区被视为最有可能的集群,而Battram被视为次要集群。然而,GLMM空间扫描统计没有检测到任何聚类,这可能是由于GLMM中随机效应的空间相关性。
    Spatial cluster analyses of health events are useful for enabling targeted interventions. Spatial scan statistic is the stateof- the-art method for this kind of analysis and the Poisson Generalized Linear Model (GLM) approach to the spatial scan statistic can be used for count data for spatial cluster detection with covariate adjustment. However, its use for modelling is limited due to data over-dispersion. A Generalized Linear Mixed Model (GLMM) has recently been proposed for modelling this kind of over-dispersion by incorporating random effects to model area-specific intrinsic variation not explained by other covariates in the model. However, these random effects may exhibit a geographical correlation, which may lead to a potential spatial cluster being undetected. To handle the over-dispersion in the count data, this study aimed to evaluate the performance of a negative binomial- GLM in spatial scan statistic on real-world data of low birth weights in Khyber-Pakhtunkhwa Province, Pakistan, 2019. The results were compared with the Poisson-GLM and GLMM, showing that the negative binomial-GLM is an ideal choice for spatial scan statistic in the presence of over-dispersed data. With a covariate (maternal anaemia) adjustment, the negative binomial-GLMbased spatial scan statistic detected one significant cluster covering Dir lower district. Without the covariate adjustment, it detected two clusters, each covering one district. The district of Peshawar was seen as the most likely cluster and Battagram as the secondary cluster. However, none of the clusters were detected by GLMM spatial scan statistic, which might be due to the spatial correlation of the random effects in GLMM.
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  • 文章类型: Journal Article
    本研究旨在使用多元线性回归和机器学习算法来预测在不同农场饲养的Akkaraman羔羊的断奶后体重。大坝年龄因素的影响,性别,羔羊的类型,企业,羊群的类型,出生体重,并对断奶体重进行了分析。该数据是从尼德省奇iftlik区多个农场饲养的总共25,316只Akkaraman羔羊中收集的。采用多元线性回归进行比较分析,随机森林,支持向量机(和支持向量回归),极端梯度提升(XGBoost)(和梯度提升),贝叶斯正则化神经网络,径向基函数神经网络,分类和回归树,穷举卡方自动交互检测(和卡方自动交互检测),和多元自适应回归样条算法。在这项研究中,使用K折交叉验证方法将测试数据集分为5层.使用诸如调整后的R平方(Adj-[公式:见正文])等性能标准比较了模型的性能均方根误差(RMSE),平均绝对偏差(MAD),和平均绝对百分比误差(MAPE),通过利用预测模型中的测试群体。此外,这些标准的低标准差的存在表明不存在过拟合问题。[公式:见文本]比较结果表明,与使用Adj-[公式:见文本]的其他算法相比,随机森林算法具有最佳的预测性能,RMSE,MAD,和MAPE值分别为0.75、3.683、2.876和10.112。总之,通过对Akkaraman羔羊的活重进行多元线性回归获得的结果不如通过人工神经网络分析获得的结果准确。
    This study was designed to predict the post-weaning weights of Akkaraman lambs reared on different farms using multiple linear regression and machine learning algorithms. The effect of factors the age of the dam, gender, type of lambing, enterprise, type of flock, birth weight, and weaning weight was analyzed. The data was collected from a total of 25,316 Akkaraman lambs raised at multiple farms in the Çiftlik District of Niğde province. Comparative analysis was conducted by using multiple linear regression, Random Forest, Support Vector Machines (and Support Vector Regression), Extreme Gradient Boosting (XGBoost) (and Gradient Boosting), Bayesian Regularized Neural Network, Radial Basis Function Neural Network, Classification and Regression Trees, Exhaustive Chi-squared Automatic Interaction Detection (and Chi-squared Automatic Interaction Detection), and Multivariate Adaptive Regression Splines algorithms. In this study, the test dataset was divided into five layers using the K-fold cross-validation method. The performance of models was compared using performance criteria such as Adjusted R-squared (Adj-[Formula: see text]), Root Mean Square Error (RMSE), Mean Absolute Deviation (MAD), and Mean Absolute Percentage Error (MAPE) by utilizing test populations in the predicted models. Additionally, the presence of low standard deviations for these criteria indicates the absence of an overfitting problem. [Formula: see text]The comparison results showed the Random Forest algorithm had the best predictive performance compared to other algorithms with Adj-[Formula: see text], RMSE, MAD, and MAPE values of 0.75, 3.683, 2.876, and 10.112, respectively. In conclusion, the results obtained through Multiple Linear Regression for the live weights of Akkaraman lambs were less accurate than the results obtained through artificial neural network analysis.
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  • 文章类型: Journal Article
    Mundeswari河,印度东部一条生态受损的河流,水质恶化主要是由于其附近的人为活动。这项研究旨在全面评估河流的污染现状,并评估河水灌溉的适宜性,鉴于其广泛用于农业目的。在为期两年(2020-2022年)的四个不同采样点(SP1-SP4)进行了每月水质监测,考虑十七个水质参数。本研究采用主成分分析/因子分析(PCA/FA)和绝对主成分得分-多元线性回归(APCS-MLR)受体模型。这些方法用于辨别和量化影响Mundeswari河水质的潜在污染源。研究表明,在季风前季节,Mundeswari河的水质退化最严重。在四个采样点中,SP3表现出最高的污染水平,平均生化需氧量(BOD)和化学需氧量(COD)分别为5.36mg/L和44.72mg/L。分别。根据单向方差分析(ANOVA),大多数水质参数存在较大的空间和季节差异(P<0.05)。PCA/FA提取了四种潜在污染源,占总方差的81.5%。影响河水水质的主要因素是自然风化过程,生活污水和废物的排放,和农业径流。APCS-MLR受体模型进一步揭示了农业排水因素以及生活污水和废物的排放对Mundeswari河的影响更大。调查得出的结论是,所有灌溉适宜性指标的平均值均低于定义的阈值限值,表明所研究河流的水似乎适合灌溉。这项研究的结果可能会为制定Mundeswari河生态复兴的可持续战略做出重大贡献。
    The Mundeswari River, an ecologically distressed river in eastern India, has been subjected to water quality deterioration largely due to anthropogenic activities in its vicinity. This study aimed to comprehensively evaluate the current state of pollution in the river and assess the appropriateness of river water for irrigation, given its extensive use for agricultural purposes. Monthly water quality monitoring was undertaken at four distinct sampling sites (SP1-SP4) over a two-year period (2020-2022), considering seventeen water quality parameters. This research employed principal component analysis/factor analysis (PCA/FA) and absolute principal component score-multiple linear regression (APCS-MLR) receptor modelling. These methodologies were used to discern and quantify potential sources of pollution influencing the water quality of the Mundeswari River. The study revealed that the water quality of the Mundeswari River was most degraded during the pre-monsoon season. Among the four sampling sites, SP3 exhibited the highest level of pollution with mean biochemical oxygen demand (BOD) and chemical oxygen demand (COD) values of 5.36 mg/L and 44.72 mg/L, respectively. According to the one-way analysis of variance (ANOVA), there was considerable spatial and seasonal disparities (P < 0.05) in most water quality parameters. The PCA/FA extracted four latent pollution sources, accounting for 81.5% of the total variance. The primary factors influencing the quality of river water are natural weathering processes, discharge of domestic effluent and waste, and agricultural runoff. The APCS-MLR receptor model further revealed that agricultural drainage factors and the discharge of domestic effluent and waste had a greater impact on the Mundeswari River. The investigation concluded that the mean values of all indicators for irrigation suitability were below the defined threshold limits, indicating that the water of the studied river appears suitable for irrigation. The outcomes of this study may significantly contribute to the formulation of sustainable strategies for the ecological rejuvenation of the Mundeswari River.
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