Image Edge Detection Based on Anti-Symmetrical Biorthogonal Wavelet Filter Banks with the Same Even Length

Xiaoyan Wang,Baochen Jiang,Chengyou Wang,Zhiqiang Yang,Xiaoyan Wang 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5

With the development of the theory of wavelet transform, biorthogonal wavelet filter banks with linear phase and compact support characteristics are widely used in signal and image processing. We study the multiscale edge detection using anti-symmetrical biorthogonal wavelet filter banks with the same even length based on the analysis of the properties of this wavelet filter banks. The steps of multiscale edge detection based on anti-symmetrical biorthogonal wavelet are introduced in detail. Experimental results on test images show that compared with the anti-symmetrical biorthogonal wavelet, the proposed anti-symmetrical biorthogonal wavelet filter banks with the same even length have better performance in terms of image edge detection. Therefore, the anti-symmetrical biorthogonal wavelet filter banks with the same even length are more suitable for image edge detection.

Rail corrugation characteristics in small radius curve section of Cologne-egg fasteners

Zhiqiang Wang,Zhenyu Lei 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

The typical passing frequencies of corrugation were obtained by analysing the measured corrugation data in small radius curve track with Cologne-egg fasteners. The threedimensional solid element model of track structure was established with the software ABAQUS, and modal analysis was carried out to determine the relationship between natural frequencies of track structure and passing frequencies of corrugation. By using the material wear model based on friction work theory, the frequency characteristics of corrugation and the development law of wear under different speeds were studied, and the control measures of corrugation were analysed. The new point of this study is to implement the above dynamic analysis from the perspective of vehicle (with flexible wheelsets) track space coupling, which can consider the coupled relationship in three directions of space. The results show that the generation of corrugation is closely related to the mechanical characteristics of track structure. Passing frequencies do not change with speeds, reflecting the frequency-fixing characteristics of corrugation. The analysis of control measures of corrugation shows that the smaller the friction coefficient is, the less likely the rail is to produce corrugation. The existence of rail vibration absorber can eliminate the generation of some short wavelength corrugation and reduce the rail bending vibration, which has a significant effect on the control of corrugation.

RPFuzzer: A Framework for Discovering Router Protocols Vulnerabilities Based on Fuzzing

( Zhiqiang Wang ),( Yuqing Zhang ),( Qixu Liu ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.8

How to discover router vulnerabilities effectively and automatically is a critical problem to ensure network and information security. Previous research on router security is mostly about the technology of exploiting known flaws of routers. Fuzzing is a famous automated vulnerability finding technology; however, traditional Fuzzing tools are designed for testing network applications or other software. These tools are not or partly not suitable for testing routers. This paper designs a framework of discovering router protocol vulnerabilities, and proposes a mathematical model Two-stage Fuzzing Test Cases Generator(TFTCG) that improves previous methods to generate test cases. We have developed a tool called RPFuzzer based on TFTCG. RPFuzzer monitors routers by sending normal packets, keeping watch on CPU utilization and checking system logs, which can detect DoS, router reboot and so on. RPFuzzer` debugger based on modified Dynamips, which can record register values when an exception occurs. Finally, we experiment on the SNMP protocol, find 8 vulnerabilities, of which there are five unreleased vulnerabilities. The experiment has proved the effectiveness of RPFuzzer.

Blood lipids and all-cause mortality among old people: the Chinese Longitudinal Healthy Longevity Survey 2008-2018

Wang Rongxi,Yu Xiaoyue,Wang Zhiqiang,Liu Yujie,Chen Hui,Liu Shangbin,XU CHENG,Chen Yingjie,Xia Danni,Ge Xin,Chang Ruijie,Xu Gang,Xiang Mi,Wang Ying,Shen Tian,Hu Fan,Cai Yong 한국역학회 2022 Epidemiology and Health Vol.44 No.-

OBJECTIVES: Proper blood lipid levels are essential for survival in older adults, but inconsistent relationships have been reported between blood lipids and all-cause mortality in the elderly. METHODS: This retrospective longitudinal study analyzed data from 1,067 Chinese older adults enrolled in the Chinese Longitudinal Healthy Longevity Survey collected in 2008 and followed up until death or December 31, 2018. The outcome was allcause mortality. Multivariate Cox regression analyses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) with stratification by age (60-80, 80-100, or ≥ 100 years) for further analysis. The survival probability according to lipid profile quartiles was calculated using Kaplan-Meier curves and the log-rank test. RESULTS: The participants’ mean age was 84.84 years, and 57.0% were female. In total, 578 individuals died, and 277 were lost to follow-up. The mean total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were higher among those who died than among those who survived. Participants in the second HDL-C quartile and the highest LDL-C and triglyceride (TG) quartiles had 28% higher, 23% lower, and 49% lower risks of all-cause mortality, respectively. After further adjustment, the associations remained except for HDL-C, and additional associations were observed between all-cause mortality and the third TC and LDL-C quartiles and the second TG quartile (HR, 1.44; 95% CI, 1.01 to 2.06; HR, 0.68; 95% CI, 0.49 to 0.94; HR, 0.79; 95% CI, 0.62 to 0.99, respectively). CONCLUSIONS: Older adults should maintain an LDL-C level of 1.91-2.47 mmol/L and a TG level of no less than 1.66 mmol/L.

Pistafolin B is the major aldose reductase inhibitor of the pods of tara [<i>Caesalpinia spinose</i> (Molina) Kuntze]

Wang, Zhiqiang,Guillen Quispe, Yanymee N.,Hwang, Seung Hwan,Zuo, Guanglei,Lim, Soon Sung Elsevier 2018 Industrial crops and products Vol.122 No.-

<P><B>Abstract</B></P> <P>Aldose reductase, the pivotal enzyme in the polyol pathway, has been widely investigated as an enzyme critically involved in the onset and progression of various pathologies associated with diabetes mellitus. Investigation of the inhibitory effect of tara [<I>Caesalpinia spinosa</I> (Molina) Kuntze] pods extract on aldose reductase revealed that its <I>n</I>-butanol fraction exhibits excellent aldose reductase inhibitory activity <I>in vitro</I> and <I>ex vivo</I>. Methyl gallate and pistafolin B were isolated from the <I>n</I>-butanol fraction of the tara pod methanolic extract as the main contributors for its aldose reductase inhibition, guided by affinity-based ultrafiltration-high performance liquid chromatography, with pistafolin B being the more potent inhibitor of the two. <I>In vitro</I> and <I>in silico</I> results demonstrated that pistafolin B is a mixed-type inhibitor that can bind to the aldose reductase active site rapidly, preventing substrate access and product formation (IC<SUB>50</SUB>, 0.198 mM; <I>K</I> <SUB>i</SUB>, 0.34 mM). <I>Ex vivo</I> experiments indicated that pistafolin B can penetrate the eye lens and successfully inhibit aldose reductase under hyperglycaemic conditions, thus preventing the accumulation of sorbitol and the subsequent osmotic stress.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The inhibitory effects of tara pods on aldose reductase activity were investigated. </LI> <LI> <I>n</I>-Butanol fraction of tara pods extract showed best aldose reductase inhibition. </LI> <LI> Aldose reductase ultrafiltration-high pressure liquid chromatography was developed. </LI> <LI> Pistafolin B was identified as a novel aldose reductase inhibitor in tara pods. </LI> </UL> </P>

Layer speciation and electronic structure investigation of freestanding hexagonal boron nitride nanosheets.

Wang, Jian,Wang, Zhiqiang,Cho, Hyunjin,Kim, Myung Jong,Sham, T K,Sun, Xuhui RSC Pub 2015 Nanoscale Vol.7 No.5

<P>Chemical imaging, thickness mapping, layer speciation and polarization dependence have been performed on single and multilayered (up to three layers and trilayered nanosheets overlapping to form 6 and 9 layers) hexagonal boron nitride (hBN) nanosheets by scanning transmission X-ray microscopy. Spatially-resolved XANES directly from freestanding regions of different layers has been extracted and compared with sample normal and 30 tilted configurations. Notably a double feature σ* excitonic state and a stable high energy σ* state were observed at the boron site in addition to the intense π* excitonic state. The boron projected σ* DOS, especially the first σ* exciton, is sensitive to surface modification, particularly in the single layered hBN nanosheet which shows more significant detectable contaminants and defects such as tri-coordinated boron/nitrogen oxide. The nitrogen site has shown very weak or no excitonic character. The distinct excitonic effect on boron and nitrogen was interpreted to the partly ionic state of hBN. Bulk XANES of hBN nanosheets was also measured to confirm the spectro-microscopic STXM result. Finally, the unoccupied electronic structures of hBN and graphene were compared.</P>

A New Three-Phase Current Modulation Method to Suppress the Commutation Torque Ripple of Brushless DC Motor

Zhiqiang Wang,Shuai Yin,Tiehua Ma 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

The brushless DC motor’s commutation torque ripple is caused by inconsistency in the rate of phase current change. Thus, a method that considers armature resistance is proposed to modulate phase current. The three-phase control strategy, which involves the “open-phase conduction, off-phase pulse width modulation, and maintained non-commutation phase” technique, is applied during commutation at full-speed segments of the motor. Changes in each phase current are analyzed theoretically by establishing mathematical model based on phase current to determine the relative difference among shutdown phase, duty, and motor operating parameters. The turn-on and turn-off phase current change rates are made to be consistent to ensure less non-commutation phase current ripple, then the torque ripple is inhibited. The simulation results show that the phase commutation current and torque ripple coefficient of the proposed method are reduced from 56.9% and 55.5% to 6.8% and 6.1%, respectively. In the experiment system, the pulsation coefficient of the motor phase current is reduced from 40.0% to 16.7% at low speed and 50.0% to 18.8% at high speed. The simulation and experimental results show that the proposed control method significantly inhibits commutation current and torque in the full section.

Color Image Coding Based on Shape-Adaptive All Phase Biorthogonal Transform

Wang, Xiaoyan,Wang, Chengyou,Zhou, Xiao,Yang, Zhiqiang Korea Information Processing Society 2017 Journal of information processing systems Vol.13 No.1

This paper proposes a color image coding algorithm based on shape-adaptive all phase biorthogonal transform (SA-APBT). This algorithm is implemented through four procedures: color space conversion, image segmentation, shape coding, and texture coding. Region-of-interest (ROI) and background area are obtained by image segmentation. Shape coding uses chain code. The texture coding of the ROI is prior to the background area. SA-APBT and uniform quantization are adopted in texture coding. Compared with the color image coding algorithm based on shape-adaptive discrete cosine transform (SA-DCT) at the same bit rates, experimental results on test color images reveal that the objective quality and subjective effects of the reconstructed images using the proposed algorithm are better, especially at low bit rates. Moreover, the complexity of the proposed algorithm is reduced because of uniform quantization.

A New Three-Phase Current Modulation Method to Suppress the Commutation Torque Ripple of Brushless DC Motor

Wang, Zhiqiang,Yin, Shuai,Ma, Tiehua The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

The brushless DC motor's commutation torque ripple is caused by inconsistency in the rate of phase current change. Thus, a method that considers armature resistance is proposed to modulate phase current. The three-phase control strategy, which involves the "open-phase conduction, off-phase pulse width modulation, and maintained non-commutation phase" technique, is applied during commutation at full-speed segments of the motor. Changes in each phase current are analyzed theoretically by establishing mathematical model based on phase current to determine the relative difference among shutdown phase, duty, and motor operating parameters. The turn-on and turn-off phase current change rates are made to be consistent to ensure less non-commutation phase current ripple, then the torque ripple is inhibited. The simulation results show that the phase commutation current and torque ripple coefficient of the proposed method are reduced from 56.9% and 55.5% to 6.8% and 6.1%, respectively. In the experiment system, the pulsation coefficient of the motor phase current is reduced from 40.0% to 16.7% at low speed and 50.0% to 18.8% at high speed. The simulation and experimental results show that the proposed control method significantly inhibits commutation current and torque in the full section.

Advances in CRISPR-Cas systems for RNA targeting, tracking and editing

Wang, Fei,Wang, Lianrong,Zou, Xuan,Duan, Suling,Li, Zhiqiang,Deng, Zixin,Luo, Jie,Lee, Sang Yup,Chen, Shi Elsevier 2019 BIOTECHNOLOGY ADVANCES Vol.37 No.5

<P><B>Abstract</B></P> <P>Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) systems, especially type II (Cas9) systems, have been widely used in gene/genome targeting. Modifications of Cas9 enable these systems to become platforms for precise DNA manipulations. However, the utilization of CRISPR-Cas systems in RNA targeting remains preliminary. The discovery of type VI CRISPR-Cas systems (Cas13) shed light on RNA-guided RNA targeting. Cas13d, the smallest Cas13 protein, with a length of only ~930 amino acids, is a promising platform for RNA targeting compatible with viral delivery systems. Much effort has also been made to develop Cas9, Cas13a and Cas13b applications for RNA-guided RNA targeting. The discovery of new RNA-targeting CRISPR-Cas systems as well as the development of RNA-targeting platforms with Cas9 and Cas13 will promote RNA-targeting technology substantially. Here, we review new advances in RNA-targeting CRISPR-Cas systems as well as advances in applications of these systems in RNA targeting, tracking and editing. We also compare these Cas protein-based technologies with traditional technologies for RNA targeting, tracking and editing. Finally, we discuss remaining questions and prospects for the future.</P> <P><B>Highlights</B></P> <P> <UL> <LI> RNA targeting and editing are becoming increasingly important </LI> <LI> CRISPR-Cas systems are advancing for RNA targeting, tracking and editing </LI> <LI> The type VI CRISPR-Cas systems are useful for RNA-guided RNA targeting </LI> <LI> Use of Cas9 and Cas13 will advance RNA-targeting technologies </LI> </UL> </P>