normalization

归一化
  • 文章类型: Journal Article
    确定标准权重在多标准决策分析中起着至关重要的作用。熵是信息科学中的一个重要指标,几种多准则决策方法利用熵权法(EWM)。在文学中,可以找到两种确定熵权法的方法。一个涉及在计算熵值之前进行归一化,而第二个没有。本文研究了基于熵的权重和Hellwig方法的归一化效果。为了比较EWM和Hellwig方法中各种归一化方法的影响,分析了一项评估2021年欧盟国家在教育领域可持续发展的研究。该研究使用了欧盟统计局的数据,这些数据与欧洲国家实现可持续发展目标4有关。观察到向量归一化和和归一化没有改变基于熵的权重。在案例研究中,最大-最小归一化影响EWM权重。同时,这些权重对实现可持续发展目标4的国家最终排名影响很小,由Hellwig的方法确定。将结果与等权重的Hellwig方法获得的结果进行比较。模拟研究是通过修改欧盟统计局的数据来进行的,以调查标准之间发现的不同归一化关系如何影响基于熵的权重和Hellwig的方法结果。
    Determining criteria weights plays a crucial role in multi-criteria decision analyses. Entropy is a significant measure in information science, and several multi-criteria decision-making methods utilize the entropy weight method (EWM). In the literature, two approaches for determining the entropy weight method can be found. One involves normalization before calculating the entropy values, while the second does not. This paper investigates the normalization effect for entropy-based weights and Hellwig\'s method. To compare the influence of various normalization methods in both the EWM and Hellwig\'s method, a study evaluating the sustainable development of EU countries in the education area in the year 2021 was analyzed. The study used data from Eurostat related to European countries\' realization of the SDG 4 goal. It is observed that vector normalization and sum normalization did not change the entropy-based weights. In the case study, the max-min normalization influenced EWM weights. At the same time, these weights had only a very weak impact on the final rankings of countries with respect to achieving the SDG 4 goal, as determined by Hellwig\'s method. The results are compared with the outcome obtained by Hellwig\'s method with equal weights. The simulation study was conducted by modifying Eurostat data to investigate how the different normalization relationships discovered among the criteria affect entropy-based weights and Hellwig\'s method results.
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  • 文章类型: Journal Article
    在经典的半定量代谢组学中,代谢物强度受生物因素和其他不需要的变化的影响。对数据处理方法进行系统评估对于确定给定实验装置的适当处理程序至关重要。当前的比较研究主要集中在峰面积数据上,而不是绝对浓度上。在这项研究中,我们评估了数据处理方法,以产生与相应的绝对量化数据最相似的输出.我们检查了数据分布特征,两种代谢物之间的倍数差异模式,和样本方差。我们使用来自零售牛奶研究和狼疮性肾炎队列的2个代谢组学数据集作为测试案例。在研究数据规范化的影响时,改造,缩放,以及这些方法的组合,我们发现交叉贡献补偿多标准归一化(ccmn)方法,后跟平方根数据转换,最适合于良好控制的研究,如牛奶研究数据集。关于狼疮性肾炎队列研究,只有ccmn归一化可以稍微改善有噪声队列的数据质量。由于评估考虑了处理数据与相应的绝对量化数据之间的相似性,我们的结果为在相似背景下处理代谢组学数据集(食物和临床代谢组学)提供了有用的指南.最后,我们引入了Metabox2.0,它可以对代谢组学数据进行彻底的分析,包括数据处理,生物标志物分析,综合分析,和数据解释。它被成功地用于处理和分析本研究中的数据。在线网络版本可在http://metsysbio.com/metabox获得。
    In classic semiquantitative metabolomics, metabolite intensities are affected by biological factors and other unwanted variations. A systematic evaluation of the data processing methods is crucial to identify adequate processing procedures for a given experimental setup. Current comparative studies are mostly focused on peak area data but not on absolute concentrations. In this study, we evaluated data processing methods to produce outputs that were most similar to the corresponding absolute quantified data. We examined the data distribution characteristics, fold difference patterns between 2 metabolites, and sample variance. We used 2 metabolomic datasets from a retail milk study and a lupus nephritis cohort as test cases. When studying the impact of data normalization, transformation, scaling, and combinations of these methods, we found that the cross-contribution compensating multiple standard normalization (ccmn) method, followed by square root data transformation, was most appropriate for a well-controlled study such as the milk study dataset. Regarding the lupus nephritis cohort study, only ccmn normalization could slightly improve the data quality of the noisy cohort. Since the assessment accounted for the resemblance between processed data and the corresponding absolute quantified data, our results denote a helpful guideline for processing metabolomic datasets within a similar context (food and clinical metabolomics). Finally, we introduce Metabox 2.0, which enables thorough analysis of metabolomic data, including data processing, biomarker analysis, integrative analysis, and data interpretation. It was successfully used to process and analyze the data in this study. An online web version is available at http://metsysbio.com/metabox.
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  • 文章类型: Journal Article
    背景:发展中国家促进可持续旅游业的重要问题之一,包括阿塞拜疆,是旅游地点的选择。应用传统方法作为此任务的解决方案,由于旅游业的当地具体情况,在这些国家的所有情况下都没有提供相关结果,统计数据的不完整,内部和外部环境的高度不确定性,以及可用信息的可疑可靠性。方法:由于统计数据有限,而用于不确定性描述的常规形式化工具没有考虑数据的可靠程度,建议基于模糊逻辑的Z扩展进行决策。与专家组进行了Delphi小组,以获取模型开发所需的信息。基于模糊Z信息的TOPSIS和PROMETHEE方法用于问题解决方案。在这些方法中,基于Z数的决策矩阵归一化过程,定义解和偏好函数之间的距离,并实现了摆动重量的确定。实现了具有Z数的直接计算。结果:通过应用基于Z数的多准则决策方法,阿塞拜疆的五个潜在地区已经根据六个标准进行了评估。这些标准反映了政府对地区发展的政策,经济,地理,环境因素,和地点的基础设施。派生解决方案在网站排名意义上具有可比性,使用这两种方法获得了相似的结果。直接计算允许基于专家的语言Z评估获得结果,而不会扭曲转换。结论:旅游部门的管理决策问题,由于上述障碍而提高,可以通过应用基于Z数的多准则方法成功解决。所获得的结果允许在高度不确定性下增加一系列决策任务,以解决可持续发展研究和其他领域的问题。
    Background: One of the vital issues in promoting the sustainable tourism industry in developing countries, including Azerbaijan, is the well-grounded selection of tourism sites. Applying traditional approaches as a solution to this task, does not provide a relevant result in all cases in these countries due to local specifics of the tourism, the incompleteness of statistical data, the high-level uncertainty of the internal and external environment, and the questionable reliability of the available information. Methods: Since the statistical data are limited, and conventional formalization tools used for uncertainty description do not consider the reliability degree of the data, it is suggested to make decisions based on the Z-extension of fuzzy logic. A Delphi panel with the expert group is conducted to obtain the information required for the model development. Fuzzy Z-information-based TOPSIS and PROMETHEE methods are applied for the problem solution. Within these approaches Z-number-based procedures of the decision matrix normalization, defining the distance between solutions and the preference function, and swing weights determination are realized. Direct computations with Z-numbers are implemented.  Results: By applying Z-number-based multi-criteria decision-making methods, five potential regions of Azerbaijan have been evaluated for six criteria. The criteria reflect government policy to the development of the regions, economical, geographical, environmental factors, and infrastructure of the locations. Derived solutions are comparable in sense of sites ranking, and similar results were obtained using both methods. Direct calculations allow obtaining results based on the linguistic Z-evaluations of experts without distorting transformations. Conclusion: The managerial decision-making problems in the tourism sector, raised due to the aforementioned barriers, can be successfully resolved by applying Z-number-based multi-criteria approaches. The obtained results allow increasing a range of the decision-making tasks under a high degree of uncertainty to be solved for sustainable development studies and other areas.
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  • 文章类型: Journal Article
    Despite the recent advances in the standardization of untargeted metabolomics workflows, there is still a lack of attention to specific data treatment strategies that require deep knowledge of the biological problem and need to be applied after a well-thought out process to understand the effect of the practice. One of those strategies is data normalization. Data-driven assumptions are critical especially addressing unwanted variation present in the biological model as it can be the case in heterogeneous tissues, cells with different sizes or biofluids with different concentrations. Chronic kidney disease (CKD) is a widespread disorder affecting kidney structure and function. Animal models are being developed to be able to get valuable insights into the etiopathogenesis of the condition and effect of the treatments. Moreover, diagnosis and disease staging still require defining appropriate biomarkers. Untargeted metabolomics has the potential to deal with those challenges. Renal fibrosis is one of the consequences of kidney injury which greatly affects the concentration of metabolites in the same quantity of sample. To overcome this challenge, several data normalization strategies have been applied, following a multilevel normalization method with the overall aim of focussing on the relevant biological information and reducing the influence of disturbing factors. A comprehensive evaluation of the performance of the normalization strategies, both on methods assessing the intragroup variation and on the impact on differential analysis, is provided. Finally, we present evidence of the importance of biological-model-driven guided normalization methods and discuss multiple criteria that need to be taken into consideration to obtain robust and reliable data. Special concern is transmitted on the misleading conclusions that might be the consequence of inappropriate data pre-treatment solutions applied for untargeted methods. Graphical abstract.
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  • 文章类型: Editorial
    Rediscoveries are not uncommon. However, sometimes they can be more significant than confirmatory or extensions of existing findings, although many authors today refer to them as discoveries in their own right. This has led to papers repeatedly rehearsing the expression \"we show here for the first time…\". When a finding has opened up a whole new field of research, this is more in line with a true discovery. When particular attention is drawn to such an event by editorials in widely read journals, such as Nature, its importance is bolstered. But if it turns out to be a rediscovery, the implications are considerable and the problem has to be brought to the attention not only of those in the same field of research, but to a wider audience to put the record straight. Consequently, acknowledgment of those who made the original discovery needs to be equally well publicised. A short discussion is presented of ways we might reduce the many claims of \"new\" discoveries that seem to be of considerable significance but are in fact rediscoveries.
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  • 文章类型: Journal Article
    尽管几种蚂蚁物种是发展分子控制策略的重要目标,只有少数研究专注于识别和验证定量逆转录聚合酶链反应(RT-qPCR)数据标准化的参考基因。我们在这里提供了一项广泛的研究,以鉴定和验证用于蚂蚁Attasexdens基因表达分析的合适参考基因,南美的一种威胁性农业害虫。参考基因的最佳数量根据每个样品而变化,并且由RefFinder产生的结果关于哪个是最合适的参考基因而不同。结果表明,根据稳定性值,RPS16,NADH和SDHB基因是样品池中最佳的参考基因。SNF7基因表达模式在所有评估的样品组中是稳定的。相比之下,当使用不太稳定的参考基因进行归一化时,记录到SNF7基因表达的大的变异性。没有适合所有分析条件的通用参考基因,因为这些基因也可以参与不同的细胞功能,因此需要对每种特定条件可能的参考基因进行系统验证。参考基因在SNF7基因标准化上的选择证实了不稳定的参考基因可能会极大地改变靶候选基因的表达谱分析。
    Although several ant species are important targets for the development of molecular control strategies, only a few studies focus on identifying and validating reference genes for quantitative reverse transcription polymerase chain reaction (RT-qPCR) data normalization. We provide here an extensive study to identify and validate suitable reference genes for gene expression analysis in the ant Atta sexdens, a threatening agricultural pest in South America. The optimal number of reference genes varies according to each sample and the result generated by RefFinder differed about which is the most suitable reference gene. Results suggest that the RPS16, NADH and SDHB genes were the best reference genes in the sample pool according to stability values. The SNF7 gene expression pattern was stable in all evaluated sample set. In contrast, when using less stable reference genes for normalization a large variability in SNF7 gene expression was recorded. There is no universal reference gene suitable for all conditions under analysis, since these genes can also participate in different cellular functions, thus requiring a systematic validation of possible reference genes for each specific condition. The choice of reference genes on SNF7 gene normalization confirmed that unstable reference genes might drastically change the expression profile analysis of target candidate genes.
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  • 文章类型: Journal Article
    Studies have pointed to a trend in Western societies toward the normalization of homosexuality and emerging \"post-gayness\" among young people, who no longer consider their sexual identity meaningful in defining themselves. This article takes a closer look at the Dutch case where tolerance is regarded as a national virtue, while society remains heteronormative. In 38 interviews with Dutch same-sex-attracted young people, we investigated the labels they used to describe their sexual orientation to reveal what they can tell us about normalization, tolerance, and heteronormativity. In their labeling strategies, participants de-emphasized their sexual identity, othered, and reinforced the hetero/homo binary. They preferred labels without connotations to gender expression. While post-gay rhetoric was ideologically appealing, its use was not an outcome of their sexual orientation having become insignificant; it rather enabled them to produce normality. We discuss the findings against the backdrop of \"Dutch tolerance,\" which rests on an ideology of normality.
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  • 文章类型: Journal Article
    BACKGROUND: Measuring how gene expression changes in the course of an experiment assesses how an organism responds on a molecular level. Sequencing of RNA molecules, and their subsequent quantification, aims to assess global gene expression changes on the RNA level (transcriptome). While advances in high-throughput RNA-sequencing (RNA-seq) technologies allow for inexpensive data generation, accurate post-processing and normalization across samples is required to eliminate any systematic noise introduced by the biochemical and/or technical processes. Existing methods thus either normalize on selected known reference genes that are invariant in expression across the experiment, assume that the majority of genes are invariant, or that the effects of up- and down-regulated genes cancel each other out during the normalization.
    RESULTS: Here, we present a novel method, moose2 , which predicts invariant genes in silico through a dynamic programming (DP) scheme and applies a quadratic normalization based on this subset. The method allows for specifying a set of known or experimentally validated invariant genes, which guides the DP. We experimentally verified the predictions of this method in the bacterium Escherichia coli, and show how moose2 is able to (i) estimate the expression value distances between RNA-seq samples, (ii) reduce the variation of expression values across all samples, and (iii) to subsequently reveal new functional groups of genes during the late stages of DNA damage. We further applied the method to three eukaryotic data sets, on which its performance compares favourably to other methods. The software is implemented in C++ and is publicly available from http://grabherr.github.io/moose2/.
    CONCLUSIONS: The proposed RNA-seq normalization method, moose2 , is a valuable alternative to existing methods, with two major advantages: (i) in silico prediction of invariant genes provides a list of potential reference genes for downstream analyses, and (ii) non-linear artefacts in RNA-seq data are handled adequately to minimize variations between replicates.
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  • 文章类型: Journal Article
    In case-control studies of the human microbiome, the goal is to evaluate whether cases differ from controls in the microbiome composition of a particular body habitat and which taxa are responsible for the differences. These studies leverage sequencing technology and spectroscopy that provide new measurements of the microbiome.
    Three challenges in conducting reproducible microbiome research using a case-control design are compensating for differences in observed and actual microbial community composition, detecting \"rare\" taxa in microbial communities, and choosing properly powered analysis methods. The significance of each challenge, evaluation of commonly held views, analysis of unanswered questions, and suggestions of strategies for solutions are discussed.
    Understanding the effects of these choices on case-control analyses has been underappreciated, with an implicit assumption that further advances in technology will address all the current shortcomings.
    It is recommended that research on the human microbiome include positive and negative control experiments to provide insight into bias, contamination, and technical variation. Research protocols such as these may afford a better opportunity to make quantitative and qualitative adjustments to data, thereby reducing the risk of falsely positive results, increasing power to discover true disease determinants, and enhancing interpretation across studies.
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  • 文章类型: Journal Article
    The combination of food quality standard and soil-plant transfer models can be used to derive critical limits of heavy metals for agricultural soils. In this paper, a robust methodology is presented, taking the variations of plant species and cultivars and soil properties into account to derive soil thresholds for lead (Pb) applying species sensitivity distribution (SSD). Three species of root vegetables (four cultivars each for radish, carrot, and potato) were selected to investigate their sensitivity differences for accumulating Pb through greenhouse experiment. Empirical soil-plant transfer model was developed from carrot New Kuroda grown in twenty-one soils covering a wide variation in physicochemical properties and was used to normalize the bioaccumulation data of non-model cultivars. The relationship was then validated to be reliable and would not cause over-protection using data from field experimental sites and published independent studies. The added hazardous concentration for protecting 95% of the cultivars not exceeding the food quality standard (HC5add) were then calculated from the Burr Type III function fitted SSD curves. The derived soil Pb thresholds based on the added risk approach (total soil concentration subtracting the natural background part) were presented as continuous or scenario criteria depending on the combination of soil pH and CEC.
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