Data Transformation Technique to Improve the Outlier Detection Power of Grubbs’ Test for Data Expected to Follow Linear Relation

Adikaram, K. K. L. B.; Hussein, Mohamed A.; Effenberger, Mathias; Becker, Thomas

doi:10.1155/2015/708948

Cited by 31 publications

(13 citation statements)

References 20 publications

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“…The logtransformation plays a crucial role here, enabling low concentrations with values of tenths and hundredths of mg/l or µg/l to be separated from each other. This gives the method added value over outlier detection methods that do not use log-transformation (Adikaram et al, 2015;Wang et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Combining statistical methods for detecting potential outliers in groundwater quality time series

Berendrecht¹,

Vliet²,

Griffioen

2022

Environ Monit Assess

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Quality control of large-scale monitoring networks requires the use of automatic procedures to detect potential outliers in an unambiguous and reproducible manner. This paper describes a methodology that combines existing statistical methods to accommodate for the specific characteristics of measurement data obtained from groundwater quality monitoring networks: the measurement series show a large variety of dynamics and often comprise few (< 25) measurements, the measurement data are not normally distributed, measurement series may contain several outliers, there may be trends in the series, and/or some measurements may be below detection limits. Furthermore, the detection limits may vary in time. The methodology for outlier detection described in this paper uses robust regression on order statistics (ROS) to deal with measured values below the detection limit. In addition, a biweight location estimator is applied to filter out any temporal trends from the series. The subsequent outlier detection is done in z-score space. Tuning parameters are used to attune the robustness and accuracy to the given dataset and the user requirements. The method has been applied to data from the Dutch national groundwater quality monitoring network, which consists of approximately 350 monitoring wells. It proved to work well in general, detecting outliers at the top and bottom of the regular measurement range and around the detection limit. Given the diversity exhibited by measurement series, it is to be expected that the method does not give 100% satisfactory results. Measured values identified by the method as potential outliers will therefore always need to be further assessed on the basis of expert knowledge, consistency with other measurement data and/or additional research.

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Section: Discussionmentioning

confidence: 99%

Combining statistical methods for detecting potential outliers in groundwater quality time series

Berendrecht¹,

Vliet²,

Griffioen

2022

Environ Monit Assess

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“…normality can be assumed). We did not perform this test on groups with less than seven data points [49]. We used the 'grubbs.test' function royalsocietypublishing.org/journal/rspb Proc.…”

Section: (D) Statistical Analysesmentioning

confidence: 99%

Do mutualistic interactions last longer than antagonistic interactions?

Zeng

Wiens

2021

Proc. R. Soc. B.

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Species interactions are crucial and ubiquitous across organisms. However, it remains unclear how long these interactions last over macroevolutionary timescales, and whether the nature of these interactions (mutualistic versus antagonistic) helps predict how long they persist. Here, we estimated the ages of diverse species interactions, based on phylogenies from 60 studies spanning the Tree of Life. We then tested if mutualistic interactions persist longer than antagonistic interactions. We found that the oldest mutualisms were significantly older than the oldest antagonisms across all organisms, and within plants, fungi, bacteria and protists. Surprisingly, this pattern was reversed in animals, with the oldest mutualisms significantly younger than the oldest antagonisms. We also found that many mutualisms were maintained for hundreds of millions of years (some greater than 1 billion years), providing strong evidence for the long-term stability of mutualisms and for niche conservatism in species interactions.

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“…In the statistical calculation method of eliminating outliers, the Grubbs test is not only applicable to the abandonment of one or more suspicious values in a group of data, but also applicable to the limited number of determinations. It is the most reliable test method for the determination of suspicious values (Adikaram et al, 2015).…”

Section: The Influence Of Laboratory Mixing Technology On Voids and Smentioning

confidence: 99%

Study on the Laboratory Mixing and Compaction Methodology of Emulsified Asphalt Cold Recycled Mixture

Liu

Han

Wu³

et al. 2020

Front. Mater.

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Emulsified asphalt cold recycled mixture is commonly used in the upper base course of expressway reconstruction asphalt pavement. When the following layer is paved with hot-mix asphalt (HMA) mixture, the aging asphalt in the recycled material is activated due to the temperature conduction effect of the HMA mixture, so that the cold recycled layer produces "secondary thermal compaction" under the action of a roller. Based on this phenomenon, the present study aimed to discuss the influence of different molding methods and mixing processes on the volume parameters and mechanical properties of cold recycled emulsified asphalt mixture. The influences of Marshall compaction times, gyratory compaction times, curing time, and specimen-forming temperature on the voids and splitting strength of cold recycled mixture were studied. The field core sample was compared with the laboratory-forming method, which accords with the field compaction condition of the cold recycled upper base. first-time compaction number of large Marshall is 150 times and secondary compaction number is 75 times (Shorthand for 150 + 75), the compaction times of the gyratory specimen is "30 + 15." The curing time of the cold recycled mixture should not exceed 3 h and should not be constructed in low-temperature weather to ensure the quality of pavement construction. The use of a new stage and step laboratory mixing process simulating the plant mixing, compared with the traditional mixing process, increases the splitting strength by at least 13%.

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Data Transformation Technique to Improve the Outlier Detection Power of Grubbs’ Test for Data Expected to Follow Linear Relation

Cited by 31 publications

References 20 publications

Combining statistical methods for detecting potential outliers in groundwater quality time series

Combining statistical methods for detecting potential outliers in groundwater quality time series

Do mutualistic interactions last longer than antagonistic interactions?

Study on the Laboratory Mixing and Compaction Methodology of Emulsified Asphalt Cold Recycled Mixture

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