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39 results on '"Wu, Chengying"'

1. GBG++: A Fast and Stable Granular Ball Generation Method for Classification

Author

Xie, Qin, Zhang, Qinghua, Xia, Shuyin, Zhao, Fan, Wu, Chengying, Wang, Guoyin, and Ding, Weiping

Subjects
Computer Science - Machine Learning
Abstract

Granular ball computing (GBC), as an efficient, robust, and scalable learning method, has become a popular research topic of granular computing. GBC includes two stages: granular ball generation (GBG) and multi-granularity learning based on the granular ball (GB). However, the stability and efficiency of existing GBG methods need to be further improved due to their strong dependence on $k$-means or $k$-division. In addition, GB-based classifiers only unilaterally consider the GB's geometric characteristics to construct classification rules, but the GB's quality is ignored. Therefore, in this paper, based on the attention mechanism, a fast and stable GBG (GBG++) method is proposed first. Specifically, the proposed GBG++ method only needs to calculate the distances from the data-driven center to the undivided samples when splitting each GB instead of randomly selecting the center and calculating the distances between it and all samples. Moreover, an outlier detection method is introduced to identify local outliers. Consequently, the GBG++ method can significantly improve effectiveness, robustness, and efficiency while being absolutely stable. Second, considering the influence of the sample size within the GB on the GB's quality, based on the GBG++ method, an improved GB-based $k$-nearest neighbors algorithm (GB$k$NN++) is presented, which can reduce misclassification at the class boundary. Finally, the experimental results indicate that the proposed method outperforms several existing GB-based classifiers and classical machine learning classifiers on $24$ public benchmark datasets.

Published
2023

16. Data-Driven Interval Granulation Approach Based on Uncertainty Principle for Efficient Classification

Author

Wu, Chengying, Zhang, Qinghua, Yin, Longjun, Xie, Qin, Luo, Nanfang, and Wang, Guoyin

Abstract

Granular computing (GrC) is an efficient way to reveal descriptions of data in line with human cognition and plays a critical role in knowledge discovery. Information granules (IGs), the basic computing unit of GrC, is the key component of knowledge representation and processing. Rough sets are one of the classical GrC models and generate IGs based on indiscernibility relations. The relations can effectively achieve the granulation of nominal attributes and generate desirable IGs, but they may cause information loss when achieving the granulation of numerical attributes. To overcome this issue, fuzzy rough sets (FRS) and neighborhood rough sets (NRS) were developed based on the rough sets. However, to generate high-performance IGs in practice, the FRS model requires prior knowledge to determine a fuzzy operation in advance, and NRS needs to calculate an optimal neighborhood radius. In addition, regardless of FRS or NRS, each object is taken as a computing unit to generate IGs that constitute a covering rather than a partition for the universe. This process is not only time-consuming but also prone to generate redundant IGs. Therefore, in this study, a data-driven interval granulation approach based on the uncertainty principle is proposed to generate justifiable interval neighborhood IGs with flexibility and tolerance. First, the interval granulation of attribute values and interval equivalence relation are defined. Next, with the interval equivalence relation, a novel interval rough sets model is developed to unify numerical and nominal attributes into one framework, and a membership function is developed without requiring prior knowledge in advance. Then, a highly effective classifier named CAR-ING integrating attribute reduction technique is developed from the perspective of interval neighborhood IGs. Finally, experiments and comparisons on 17 widely used UCI benchmark datasets and 3 real Biobank medical datasets from the U.K. demonstrated that CAR-ING performs significantly better than four state-of-the-art classifiers based on GrC and five classical classifiers in machine learning. Additionally, the efficiency of CAR-ING is demonstrated on 20 datasets.

Published
2024
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18. A Neighborhood Covering Classifier Based on Optimal Granularity of Fuzzy Quotient Space

Author

Zhao, Fan, Zhang, Qinghua, Wu, Chengying, Dai, Yongyang, Xie, Qin, Wang, Guoyin, and Xia, Shuyin

Abstract

As one of the rapidly developing methodologies for dealing with complex problems in line with human cognition, granular computing has made significant achievements in knowledge discovery. Neighborhood classifier, as a typical description of granular computing, is an effective method for the classification of continuous data. However, in the phase of constructing neighborhood rules, the existing neighborhood classifiers are divided into the following two modes and both have defects: 1) the strategy driven by center: there are a lot of overlap and inclusion among neighborhood rules, that is, it needs to spend much time to reduce redundancy rules; and 2) the strategy driven by rule: there are many rules containing only one object, which cannot form an effective covering and would affect knowledge acquisition in the incremental environment. Therefore, in this article, fuzzy quotient space theory is introduced to construct neighborhood rules. Based on the optimal granularity of fuzzy quotient space, first, a neighborhood covering classifier, which has no redundant rules and could form the effective covering, is proposed without any artificial parameter. Second, comprehensively considering the knowledge purity and complexity, the quality measure of granularity is proposed, which guides the optimal granularity selection of hierarchical quotient space structure. Third, neighborhood rules are constructed in optimal granularity. Then, the offset of center is introduced to describe the membership degree of the test object to different neighborhood rules, and the neighborhood allocation strategy is proposed accordingly. Next, an algorithm for the neighborhood covering classifier based on these theories is proposed. Finally, experiments on 13 UCI datasets and three real datasets are carried out to verify the performance of the proposed classifier from four common classification indexes.

Published
2023
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20. A Series of Deoxyfluorination Reagents Featuring OCF2 Functional Groups

Author

Qing-Yun Chen, Cao Wei, Yong Guo, Wu Chengying, Shiyu Zhao, and Zhaoben Su

Subjects
chemistry.chemical_compound, 010405 organic chemistry, Chemistry, Reagent, Organic Chemistry, Organic chemistry, Ether, Physical and Theoretical Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, 0104 chemical sciences
Abstract

Research on perfluoroalkyl ether carboxylic acids (PFECAs) as alternatives for perfluoroalkyl substances continues with the goal of protecting the environment. However, very little is known about t...

Published
2020

26. The surface properties of amine oxides with a fluoroether chain

Author

Qing-Yun Chen, Longhao Dai, Qing Shen, Zhi-Gang Zhao, Zhaoben Su, Qin Su, Yong Guo, Wu Chengying, and Meiwei Huang

Subjects
chemistry.chemical_classification, 010405 organic chemistry, Chemistry, Organic Chemistry, Limiting, 010402 general chemistry, 01 natural sciences, Biochemistry, Medicinal chemistry, 0104 chemical sciences, Inorganic Chemistry, Hydrocarbon, Critical micelle concentration, Environmental Chemistry, Molecule, Free energies, Amine gas treating, Physical and Theoretical Chemistry
Abstract

Persistent organic pollutants (POPs) includes long-chained fluorosurfactants, for instance, perfluorooctanonate (PFOA) and perfluorooctanesulfonate (PFOS). In order to find out alternative fluorosurfactants, we synthesized eight amine oxides with a fluoroether chain. Their surface properties were evaluated and compared with perfluoroalkyl and hydrocarbon analogues. The surface tensions at critical micelle concentration (γcmc) for the eight amine oxides with a fluoroether chain were at a range from 15.5 to 23.0 mN/m, and γcmc of four fluoroether amine oxides were below 17 mN/m comparable to perfluorooctyl analogues (16.4 mN/m) and much lower than perfluorohexyl (20.5 mN/m) and hydrocarbon analogues (24.2 and 24.7 mN/m). The critical micelle concentration (cmc) for the eight amine oxides with a fluoroether chain were 3 to 535 × 10−4 mol/L. The cmc of four fluoroether amine oxides were 3 to 21 × 10−4 mol/L (0.2 to 1.0 g/L) comparable to perfluorooctyl (0.4 g/L) and hydrocarbon analogues (4 and 10 × 10−4 mol/L) and much lower than perfluorohexyl analogue (36.9 g/L). The surface excesses, the limiting molecule areas and the free energies of micellization of amine oxides were calculated. Fluoroether surfactants are promising alternatives for PFOA and PFOS.

Published
2021

27. Gemini cationic surfactants with flexible perfluorinated-ether chains

Author

Hu Yang, Wu Chengying, Du Fangqiong, Cao Wei, Yong Guo, Wang Mengying, Meiwei Huang, Xie Weidong, and Qing-Yun Chen

Subjects
Perfluorooctanesulfonic acid, 010405 organic chemistry, Organic Chemistry, Cationic polymerization, Ether, 010402 general chemistry, 01 natural sciences, Biochemistry, Surface energy, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Critical micelle concentration, Polymer chemistry, Environmental Chemistry, Perfluorooctanoic acid, Ammonium, Physical and Theoretical Chemistry, Methylene
Abstract

This research aims at providing alternatives for long-chain fluorosurfactants, such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and their derivatives. Gemini quaternary ammonium fluorosurfactants with perfluorinated-ether chains were synthesized and their surface tensions were measured. The surface tensions at critical micelle concentration (γcmc) are at the range of 14.7–23.3 mN/m and among them γcmc of four perfluorinated-chain surfactants are below 16 mN/m.We found that the flexibility of perfluorinated-ether chains, such as CF3(OCF2)n-, contributed significantly to enhance the surface activities. We also synthesized gemini cationic surfactants with C6F13CH2CH2- groups and their γcmc are between 15.5 to 20.1 mN/m. Good linkage design, such as -(CH2)n- (where n is odd), -CH2CH2OCH2CH2- and 1,2-phenylenebis(methylene), helps for lowering surface energy. The current research provides an approach for discovering non-bioaccumulative surfactants.

Published
2020

28. Deoxyfluorination of Carboxylic, Sulfonic, Phosphinic Acids and Phosphine Oxides by Perfluoroalkyl Ether Carboxylic Acids Featuring CF2O Units.

Author

Zhao, Shiyu Please verify that the linked ORCID identifiers are correct for each author., Guo, Yong, Su, Zhaoben, Wu, Chengying, Chen, Wei, and Chen, Qing‐Yun

Subjects
PHOSPHINIC acid, PHOSPHINE oxides, CARBOXYLIC acids, PERFLUOROOCTANOIC acid, ETHERS, POTASSIUM salts, FLUORIDES, SULFONYL compounds
Abstract

Main observation and conclusion: The deoxyfluorination of carboxylic, sulfonic, phosphinic acids and phosphine oxides is a fundamentally important approach to access acyl fluorides, sulfonyl fluorides and phosphoric fluorides, thus the development of inexpensive, stable, easy‐to‐handle, versatile, and efficient deoxyfluorination reagents is highly desired. Herein, we report the use of potassium salts of perfluoroalkyl ether carboxylic acids (PFECA) featuring CF2O units as deoxyfluorination reagents, which are generated mainly as by‐products in the manufacture of hexafluoropropene oxide (HFPO). The synthesis of acyl fluorides, sulfonyl fluorides and phosphoric fluorides can be realized via carbonic difluoride (COF2) generated in situ from thermal degradation of the PFECA salt. [ABSTRACT FROM AUTHOR]

Published
2021
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31. A Series of Deoxyfluorination Reagents Featuring OCF2Functional Groups

Author

Zhao, Shiyu, Guo, Yong, Su, Zhaoben, Cao, Wei, Wu, Chengying, and Chen, Qing-Yun

Abstract

Research on perfluoroalkyl ether carboxylic acids (PFECAs) as alternatives for perfluoroalkyl substances continues with the goal of protecting the environment. However, very little is known about the utilization of decomposition products of PFECAs. We report herein a new series of deoxyfluorination reagents featuring OCF2functional groups derived from certain PFECAs. Alkyl fluorides were generated from various alcohols in ≤97% yield by these novel reagents. The mechanistic experiment verified in situgeneration of carbonic difluoride (COF2).

Published
2020
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32. Trace Elements Characteristic Based on ICP-AES and the Correlation of Flavonoids from <italic>Sparganii rhizoma</italic>.

Author

Wang, Xinsheng, Wu, Yanfang, Wu, Chengying, Wu, Qinan, and Niu, Qingshan

Abstract

The aim of the present work was to investigate the trace elements and the correlation with flavonoids from Sparganii rhizoma. The ICP-AES and ultraviolet-visible spectroscopy were employed to analyze trace elements and flavonoids. The concentrations of trace elements and flavonoids were calculated using standard curve. The content of flavonoids was expressed as rutin equivalents. The cluster analysis was applied to evaluate geographical features of S. rhizoma from different geographical regions. The correlation analysis was used to obtain the relationship between the trace elements and flavonoids. The results indicated that the 15 trace elements were measured and the K, Ca, Mg, Na, Mn, Al, Cu, and Zn are rich in Sparganii rhizome. The different producing regions samples were classified into four groups. There was a weak relationship between trace elements and flavonoids. [ABSTRACT FROM AUTHOR]

Published
2018
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37. Determination of Seven Phenolic Compounds in Rhizoma Sparganii by RP-HPLC.

Author

Wang, Xinsheng, Wu, Qi-nan, Wu, Yanfang, Wu, Chengying, Yue, Wei, and Liang, Qiaoli

Subjects
PHENOLS, SPARGANIACEAE, HIGH performance liquid chromatography, ACETIC acid, TEMPERATURE effect, PHARMACEUTICAL research, REGRESSION analysis
Abstract

A reversed-phase high-performance liquid chromatographic method was developed for the simultaneous quantification of seven phenolic compounds from Rhizoma Sparganii. The samples were separated on a Waters SunFire C18 column with a temperature of 30°C. Gradient elution was applied, using 0.8% acetic acid (solvent A) and methanol (solvent B) with a flow rate of 1.0 mL/min, and detection wavelength was 280 nm. The validation of the method included linearity, precision, repeatability, stability and recovery. The calibration curves showed good linear regression (R2 > 0.9996) within the test range. The developed method indicated good precision and accuracy, with the overall intra-day and inter-day variation at less than 3%. The range of recoveries for the seven analytes was 95.34–100.06% with relative standard deviation < 3.08 %. The established method was successfully applied for the determination of seven phenolic compounds in 12 batches of Rhizoma Sparganii. The study may be useful in the quality evaluation of Rhizoma Sparganii, and can provide technical support for pharmacological and clinical research of related drugs. [ABSTRACT FROM PUBLISHER]

Published
2013
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38. A Series of Deoxyfluorination Reagents Featuring OCF 2 Functional Groups.

Author

Zhao S, Guo Y, Su Z, Cao W, Wu C, and Chen QY

Abstract

Research on perfluoroalkyl ether carboxylic acids (PFECAs) as alternatives for perfluoroalkyl substances continues with the goal of protecting the environment. However, very little is known about the utilization of decomposition products of PFECAs. We report herein a new series of deoxyfluorination reagents featuring OCF 2 functional groups derived from certain PFECAs. Alkyl fluorides were generated from various alcohols in ≤97% yield by these novel reagents. The mechanistic experiment verified in situ generation of carbonic difluoride (COF 2 ).

Published
2020
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39. Simultaneous Determination of 16 Nucleosides and Nucleobases in Euryale ferox Salisb. by Liquid Chromatography Coupled with Electro Spray Ionization Tandem Triple Quadrupole Mass Spectrometry (HPLC-ESI-TQ-MS/MS) in Multiple Reaction Monitoring (MRM) Mode.

Author

Wang H, Wu Q, Wu C, and Jiang Z

Subjects
Limit of Detection, Linear Models, Nucleosides chemistry, Nucleosides isolation & purification, Principal Component Analysis, Reproducibility of Results, Tandem Mass Spectrometry methods, Chromatography, High Pressure Liquid methods, Nucleosides analysis, Nymphaeaceae chemistry, Plant Extracts chemistry, Spectrometry, Mass, Electrospray Ionization methods
Abstract

In this study, a simple, rapid, efficient analytical method was established for the qualification and quantification of 16 nucleosides and nucleobases in Euryale ferox Salisb. by using liquid chromatography coupled with electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-TQ-MS/MS) in multiple-reaction monitoring (MRM) mode. Ideal separation of 16 target compounds was achieved on Xbridge Amide HILIC column (4.6 × 150 mm, 3.5 μm) with gradient elution in 11 min by optimized conditions. Variations of nucleosides and nucleobase in samples from different cultivation regions ranging from 190.50 to 1594.30 μg/g were obvious. The total nucleoside contents were higher than total nucleobases, especially in the compositions of guanosine, cytidine and 2'-deoxyguanosine. Samples 1-18 with dense thorns were better characters than samples 19-26 without thorns in terms of nucleosides and nucleobases concentrations in general. The limits of detection (LODs) and quantification (LOQs) for 16 analytical substances were investigated to be 0.11-6.33 ng/mL and 0.35-21.1 ng/mL, respectively. And the method was first applied to large aquatic plants with good linearity, precision, repeatability and accuracy. All present information provided a scientific and rational reference for quality assessment and control of Euryale ferox Salisb., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Published
2015
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