Although there are many measures of variability for qualitative variables, they are little used in social research, nor are they included in statistical software. The aim of this article is to present six measures of ...Although there are many measures of variability for qualitative variables, they are little used in social research, nor are they included in statistical software. The aim of this article is to present six measures of variation for qualitative variables of simple calculation, as well as to facilitate their use by means of the R software. The measures considered are, on the one hand, Freemans variation ratio, Morals universal variation ratio, Kvalseths standard deviation from the mode, and Wilcoxs variation ratio which are most affected by proximity to a constant random variable, where the measures of variability for qualitative variables reach their minimum value of 0. On the other hand, the Gibbs-Poston index of qualitative variation and Shannons relative entropy are included, which are more affected by the proximity to a uniform distribution, where the measures of variability for qualitative variables reach their maximum value of 1. Point and interval estimation are addressed. Bootstrap by the percentile and bias-corrected and accelerated percentile methods are used to obtain confidence intervals. Two calculation situations are presented: with a sample mode and with two or more modes. The standard deviation from the mode among the six considered measures, and the universal variation ratio among the three variation ratios, are particularly recommended for use.展开更多
The current study proposes a novel technique for feature selection by inculcating robustness in the conventional Signal to noise Ratio(SNR).The proposed method utilizes the robust measures of location i.e.,the“Median...The current study proposes a novel technique for feature selection by inculcating robustness in the conventional Signal to noise Ratio(SNR).The proposed method utilizes the robust measures of location i.e.,the“Median”as well as the measures of variation i.e.,“Median absolute deviation(MAD)and Interquartile range(IQR)”in the SNR.By this way,two independent robust signal-to-noise ratios have been proposed.The proposed method selects the most informative genes/features by combining the minimum subset of genes or features obtained via the greedy search approach with top-ranked genes selected through the robust signal-to-noise ratio(RSNR).The results obtained via the proposed method are compared with wellknown gene/feature selection methods on the basis of performance metric i.e.,classification error rate.A total of 5 gene expression datasets have been used in this study.Different subsets of informative genes are selected by the proposed and all the other methods included in the study,and their efficacy in terms of classification is investigated by using the classifier models such as support vector machine(SVM),Random forest(RF)and k-nearest neighbors(k-NN).The results of the analysis reveal that the proposed method(RSNR)produces minimum error rates than all the other competing feature selection methods in majority of the cases.For further assessment of the method,a detailed simulation study is also conducted.展开更多
The size distribution of the broken top coal blocks is an important factor,affecting the recovery ratio and the efficiency of drawing top coal in longwall top coal caving(LTCC)mining panel.The standard deviation of to...The size distribution of the broken top coal blocks is an important factor,affecting the recovery ratio and the efficiency of drawing top coal in longwall top coal caving(LTCC)mining panel.The standard deviation of top coal block size(dt)is one of the main parameters to reflect the size distribution of top coal.To find the effect of dt on the caving mechanism,this study simulates experiments with 9 different dt by using discrete element software PFC.The dt is divided into two stages:uniform distribution stage(UDS)whose dt is less than 0.1(Schemes 1–5),and nonuniform distribution stage(NDS)whose dt is more than 0.1(Schemes 6–9).This research mainly investigates the variation of recovery ratio,drawing body shape,boundary of top coal,and contact force between particles in the two stages,respectively.The results showed that with the increasing dt,the recovery ratio of the panel increases first and then decreases in UDS.It is the largest in Scheme 3,which mainly increases the drawing volume at the side of starting drawing end.However,the recovery ratio decreases first and then increases quickly in NDS,and it is the largest in Scheme 9,where the drawing volume at the side of finishing drawing end are relatively higher.In UDS,the major size of top coal is basically medium,while in NDS,the size varies from medium to small,and then to large,with a distinct difference in shape and volume of the drawing body.When the major size of top coal is medium and small,the cross-section width of the initial boundary of top coal at each height is relatively small.Conversely,when the top coal size is large,the initial boundary of top coal has a larger opening range,the rotating angle of lower boundary is relatively small in the normal drawing stage,which is conducive to the development of drawing body and reduces the residual top coal,and the maximum particle velocity and the particles movement angle are both larger.This study lays a foundation for the prediction of recovery ratio,and suggests that the uniform top coal is more mana展开更多
The mixing degree upstream of the diverging area is one of the important factors influencing the pollutant allocation characteristics of braided rivers,but the effect remains unclear at present.In this paper,physical ...The mixing degree upstream of the diverging area is one of the important factors influencing the pollutant allocation characteristics of braided rivers,but the effect remains unclear at present.In this paper,physical model tests were designed to study the effect on the pollutant flux ratio with six branching forms and a series of longitudinal discharge distances.The results indicated that the mixing degree upstream of the diverging area,which is closely related to the longitudinal discharge distance,notably affected the pollutant flux ratio.The lower the mixing degree,the larger was the deviation of the pollutant flux ratio from the discharge ratio.Moreover,a linear relationship was attained between the dimensionless mixing degree and the dimensionless deviation of the pollutant flux ratio from the discharge ratio.Consideration of different branching angles or different water layers or different branches did not affect this trend.The experimental results further demonstrated that the intercept and slope of the aforementioned linear relationship depended on the branching angle and exhibited an opposite monotonicity with a symmetric branch angle as the dividing point.These results help towards a better understanding of the mechanism of the factors influencing pollutant transport in complicated braided rivers,and provide a new approach to predicting the pollutant flux ratio of braided rivers.展开更多
The role of Photovoltaic technologies integrated or attached to the building envelope is crucial in managing the building energy demand.In this paper,the performance of PV technologies with the mounting methods of Bui...The role of Photovoltaic technologies integrated or attached to the building envelope is crucial in managing the building energy demand.In this paper,the performance of PV technologies with the mounting methods of Build-ing integrated and Free-standing(Building attached)is discussed for six different climate zone of the country.A PVGIS program proposed with three PV cell technologies(Crystalline Silicon,Copper indium diselenide,Cad-mium Telluride)is used to evaluate monthly energy generation potential and losses of the 2 kW p grid-connected PV system at the latitude and 90°.A 2 kW p PV system is chosen for Economic Weaker Section(EWS)housing schemes depending upon the roof area.From the evaluation,the performance parameter has been estimated.A new parameter Energy Deviation(ED),is proposed to choose the best PV technology in terms of performance.The results of ED agree with the parameters Performance Ratio(PR)and Capacity Factor(CF)defined under the IEC Standard 61724.The potential generation of PV technologies at 90°varies from 41%(Warm and Humid)to 64%(Cold and Sunny)when compared with the latitude.In case of Cold and Sunny and Cold and Cloudy at 90°,the generation performance of Copper indium diselenide is found better in Building integrated and Free-standing mounting methods,respectively.For the remaining zones,Cadmium Telluride technology shows better results.The Percentage loss in the system is found to be minimum in the case of Cold and Sunny,varies between 17%and 25%,and maximum is found for Warm and Humid and varies between 23.2%and 33.4%for the proposed PV technologies.The grid feed-in energy from these EWS houses for all the technologies and climatic zones is found above 45%.It is seen that the combined energy generation from the envelopes(Roof,walls,and facades)makes the houses energy plus in nature.The study has important implications for the government to promote the building integrated Photovoltaic policies in the country.展开更多
文摘Although there are many measures of variability for qualitative variables, they are little used in social research, nor are they included in statistical software. The aim of this article is to present six measures of variation for qualitative variables of simple calculation, as well as to facilitate their use by means of the R software. The measures considered are, on the one hand, Freemans variation ratio, Morals universal variation ratio, Kvalseths standard deviation from the mode, and Wilcoxs variation ratio which are most affected by proximity to a constant random variable, where the measures of variability for qualitative variables reach their minimum value of 0. On the other hand, the Gibbs-Poston index of qualitative variation and Shannons relative entropy are included, which are more affected by the proximity to a uniform distribution, where the measures of variability for qualitative variables reach their maximum value of 1. Point and interval estimation are addressed. Bootstrap by the percentile and bias-corrected and accelerated percentile methods are used to obtain confidence intervals. Two calculation situations are presented: with a sample mode and with two or more modes. The standard deviation from the mode among the six considered measures, and the universal variation ratio among the three variation ratios, are particularly recommended for use.
基金King Saud University for funding this work through Researchers Supporting Project Number(RSP2022R426),King Saud University,Riyadh,Saudi Arabia.
文摘The current study proposes a novel technique for feature selection by inculcating robustness in the conventional Signal to noise Ratio(SNR).The proposed method utilizes the robust measures of location i.e.,the“Median”as well as the measures of variation i.e.,“Median absolute deviation(MAD)and Interquartile range(IQR)”in the SNR.By this way,two independent robust signal-to-noise ratios have been proposed.The proposed method selects the most informative genes/features by combining the minimum subset of genes or features obtained via the greedy search approach with top-ranked genes selected through the robust signal-to-noise ratio(RSNR).The results obtained via the proposed method are compared with wellknown gene/feature selection methods on the basis of performance metric i.e.,classification error rate.A total of 5 gene expression datasets have been used in this study.Different subsets of informative genes are selected by the proposed and all the other methods included in the study,and their efficacy in terms of classification is investigated by using the classifier models such as support vector machine(SVM),Random forest(RF)and k-nearest neighbors(k-NN).The results of the analysis reveal that the proposed method(RSNR)produces minimum error rates than all the other competing feature selection methods in majority of the cases.For further assessment of the method,a detailed simulation study is also conducted.
基金supported by the National Key R&D Plan of China,China(Grant No.2018YFC0604501)the Natural Science Foundation of China,China(Grant Nos.51934008,51674264,51904305)the Research Fund of the State Key Laboratory of Coal Resources and Safe Mining,CUMT,China(Grant No.SKLCRSM19KF023).
文摘The size distribution of the broken top coal blocks is an important factor,affecting the recovery ratio and the efficiency of drawing top coal in longwall top coal caving(LTCC)mining panel.The standard deviation of top coal block size(dt)is one of the main parameters to reflect the size distribution of top coal.To find the effect of dt on the caving mechanism,this study simulates experiments with 9 different dt by using discrete element software PFC.The dt is divided into two stages:uniform distribution stage(UDS)whose dt is less than 0.1(Schemes 1–5),and nonuniform distribution stage(NDS)whose dt is more than 0.1(Schemes 6–9).This research mainly investigates the variation of recovery ratio,drawing body shape,boundary of top coal,and contact force between particles in the two stages,respectively.The results showed that with the increasing dt,the recovery ratio of the panel increases first and then decreases in UDS.It is the largest in Scheme 3,which mainly increases the drawing volume at the side of starting drawing end.However,the recovery ratio decreases first and then increases quickly in NDS,and it is the largest in Scheme 9,where the drawing volume at the side of finishing drawing end are relatively higher.In UDS,the major size of top coal is basically medium,while in NDS,the size varies from medium to small,and then to large,with a distinct difference in shape and volume of the drawing body.When the major size of top coal is medium and small,the cross-section width of the initial boundary of top coal at each height is relatively small.Conversely,when the top coal size is large,the initial boundary of top coal has a larger opening range,the rotating angle of lower boundary is relatively small in the normal drawing stage,which is conducive to the development of drawing body and reduces the residual top coal,and the maximum particle velocity and the particles movement angle are both larger.This study lays a foundation for the prediction of recovery ratio,and suggests that the uniform top coal is more mana
基金supported by the National Natural Science Foundation of China(No.51879176)the Jiangxi Provincial Water Conservancy Science and Technology Project(No.202022YBKT09),China。
文摘The mixing degree upstream of the diverging area is one of the important factors influencing the pollutant allocation characteristics of braided rivers,but the effect remains unclear at present.In this paper,physical model tests were designed to study the effect on the pollutant flux ratio with six branching forms and a series of longitudinal discharge distances.The results indicated that the mixing degree upstream of the diverging area,which is closely related to the longitudinal discharge distance,notably affected the pollutant flux ratio.The lower the mixing degree,the larger was the deviation of the pollutant flux ratio from the discharge ratio.Moreover,a linear relationship was attained between the dimensionless mixing degree and the dimensionless deviation of the pollutant flux ratio from the discharge ratio.Consideration of different branching angles or different water layers or different branches did not affect this trend.The experimental results further demonstrated that the intercept and slope of the aforementioned linear relationship depended on the branching angle and exhibited an opposite monotonicity with a symmetric branch angle as the dividing point.These results help towards a better understanding of the mechanism of the factors influencing pollutant transport in complicated braided rivers,and provide a new approach to predicting the pollutant flux ratio of braided rivers.
文摘The role of Photovoltaic technologies integrated or attached to the building envelope is crucial in managing the building energy demand.In this paper,the performance of PV technologies with the mounting methods of Build-ing integrated and Free-standing(Building attached)is discussed for six different climate zone of the country.A PVGIS program proposed with three PV cell technologies(Crystalline Silicon,Copper indium diselenide,Cad-mium Telluride)is used to evaluate monthly energy generation potential and losses of the 2 kW p grid-connected PV system at the latitude and 90°.A 2 kW p PV system is chosen for Economic Weaker Section(EWS)housing schemes depending upon the roof area.From the evaluation,the performance parameter has been estimated.A new parameter Energy Deviation(ED),is proposed to choose the best PV technology in terms of performance.The results of ED agree with the parameters Performance Ratio(PR)and Capacity Factor(CF)defined under the IEC Standard 61724.The potential generation of PV technologies at 90°varies from 41%(Warm and Humid)to 64%(Cold and Sunny)when compared with the latitude.In case of Cold and Sunny and Cold and Cloudy at 90°,the generation performance of Copper indium diselenide is found better in Building integrated and Free-standing mounting methods,respectively.For the remaining zones,Cadmium Telluride technology shows better results.The Percentage loss in the system is found to be minimum in the case of Cold and Sunny,varies between 17%and 25%,and maximum is found for Warm and Humid and varies between 23.2%and 33.4%for the proposed PV technologies.The grid feed-in energy from these EWS houses for all the technologies and climatic zones is found above 45%.It is seen that the combined energy generation from the envelopes(Roof,walls,and facades)makes the houses energy plus in nature.The study has important implications for the government to promote the building integrated Photovoltaic policies in the country.
