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Feature Selection Based on Dynamic Weight Boosting Algorithm
Cheng Zengping 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.12
Based on the problem that data simple weight is unchanged in current feature selection algorithms, we proposed a new boosting feature selection algorithm framework using data sampling technique to describe the change of data sample weight in the process of feature selection which can solve the problem that dynamic mutual information is sensitive to noise data. This method evaluates mutual information value among features by dynamic adjust data sample weights in the process of feature selection so that every selected feature can describe characteristics of data classification more precisely. Efficiency of this algorithm has been testified by experience results on UCI common test data sets.
Injectable PTHF-based thermogelling polyurethane implants for long-term intraocular application
Kaiwen Zhang,Zengping Liu,Qianyu Lin,Yi Jian Boo,Valerie Ow,Xinxin Zhao,Daniel Soo Lin Wong,Jason Y. C. Lim,Kun Xue,Xinyi Su,Decheng Wu,Xian Jun Loh 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4
Background: Hydrogels show great potential to be used for intraocular applications due to their high-water content and similarity to the native vitreous. Injectable thermosensitive hydrogels through a small-bore needle can be used as a delivery system for drugs or a tamponading substitute to treat posterior eye diseases with clear clinical potential. However, none of the currently available thermosensitive hydrogels can provide intraocular support for up to 3 months or more. Method: In this study, an injectable polytetrahydrofuran (PTHF)-based thermosensitive hydrogel was synthesized by polyurethane reaction. We examined the injectability, rheological properties, microstructure, cytotoxicity, and in vivo compatibility and stability of the hydrogels in rabbit eyes. Results: We found that the PTHF block type and PTHF component ratio could modulate thermogelation properties of the polyurethane polymers. The PTHF-based hydrogel implants retained normal retinal structure and function. Incorporating bioinert PTHF generated highly biocompatible and more stable thermogels in the vitreous cavity, with gel networks and the presence of polymer still observed after 3 months when other thermogels would have been completely cleared. Moreover, despite lacking hydrolytically cleavable linkages, the polymers could be most naturally removed from the native vitreous by bio-erosion without additional surgical interventions. Conclusion: Our findings suggest the potential of incorporating hydrophobic bioinert blocks to enhance the in vivo stability of supramolecularly associated hydrogels for long-term intraocular applications.
Application of Archimedean Copulas to the Analysis of Drought Decadal Variation in China
Dongdong Zuo,Guolin Feng,Zengping Zhang,Wei Hou 한국기상학회 2018 Asia-Pacific Journal of Atmospheric Sciences Vol.54 No.2
The joint probability and return period were calculated to analyze the drought characteristics and decadal variation. According to the fit analysis, the Gumbel-Hougaard copula provided the best fit to the observed data. Based on four drought duration classifications and four severity classifications, the drought events were divided into 16 drought types according to the different combinations of duration and severity classifications, and the probability and return period were analyzed for different drought types. The results showed that the occurring probability of six common drought types (0 < D ≤ 1 and 0.5 < S ≤ 1, 1 < D ≤ 3 and 0.5 < S ≤ 1, 1 < D ≤ 3 and 1 < S ≤ 1.5, 1 < D ≤ 3 and 1.5 < S ≤ 2, 1 < D ≤ 3 and 2 < S, and 3 < D ≤ 6 and 2 < S) accounted for 76% of the total probability of all types.