Research on Pixel Unmixing based on Support Vector Machine

Yunfeng Liu,Laijun Lu 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.7

Through the research of the application of support vector machine theory in the pixel unmixing, the advantages of the weighted posterior probability support vector machine theory in pixel unmixing is presented. Considering the difference of each support vector machine classifier, posterior probability pixel is used as weight coefficient of sub-pixel classification for pixels unmixing. This paper presents a weighted posterior probability support vector machine mixed pixel unmixing method. This method not only has the nonlinear model decomposition characteristics of high precision, but also reduces the standard support vector machine calculating the amount of multi classifier, and it has strong adaptability.

Experimental and Numerical Investigation on the Cyclic Behavior of SRC Columns considering Unsymmetrical Confinement Effect

Xianpan Liu,Lei Zeng,Yunfeng Xiao,Yanhua Liu,Heng Zhang,Yun Cao 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.4

Experimental and numerical studies were conducted on the cyclic behavior of steel reinforced concrete (SRC) columns with T-shaped and L-shaped steel section. A total of 8 SRC columns were tested under axial compression and lateral cyclic loading. The design details, loading procedure and main results, including the failure modes, hysteretic characteristics and ductility were reported. Four failure modes as flexural failure, shear bond failure, shear compression failure and shear compound failure were observed. By considering various unsymmetrical confinement and plastic hinge region, the experimental study was supplemented by numerical analysis to study the influence of axial compression ratio, shear-span ratio and concrete strength. The results revealed that the FEA is in good agreement with the experimental results. The ultimate loading of specimen with confinement effect has been improved by 21.4% − 33.8%. The failure modes is dominated by the shear-span ratio and type of cross section. The specimens with smaller shear-span ratio are prone to shear failure, while the unsymmetrical steel arrangement causes shear compound failure which is combined with shear bond failure and shear compression failure. Moreover, the specimens with larger shear-span ratio and stirrup ratio present greater deformation capacity and ductility. In practical engineering, the confinement degree of SRC columns with unsymmetrical steel section can be enhanced by increasing the stirrup ratio and arranging the cross ties.

Logical Connectivity Prediction Models for VANET based on Nonlinear Regression and ELM : An Example of the AODV Protocol

Haiqing Liu,Licai Yang,Sijing Ding,Yunfeng Shi 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.6

Differing from the physical connectivity of the topology structure, the logical connectivity of VANET considers both the interior network configuration and the external communication environment. Hence, the traditional mathematical analysis and modeling methods which are usually used in physical connectivity research are no longer suitable for the logical connectivity prediction. Taking the AODV protocol as an example, this paper simulates the effects of different road traffic parameters on logical connectivity probability and selects three main effect factors, roadway length, vehicle number and vehicle speed. Furthermore, the inner relation between the logical connectivity and the three road traffic parameters is studied based on data mining technique and then two logical connectivity prediction models are presented, the nonlinear regression-based model and the extreme learning machine-based model. Simulation results show that the two models are both with high accuracy in predicting the network logical connectivity under different road traffic environments.

Ginsenoside Rk1 inhibits HeLa cell proliferation through an endoplasmic reticulum signaling pathway

Qiuyang Li,Hang Sun,Shiwei Liu,Jinxin Tang,Shengnan Liu,Pei Yin,Qianwen Mi,Jingsheng Liu,Lei yu,Yunfeng Bi 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.5

Background: Changes to work-life balance has increased the incidence of cervical cancer among youngerpeople. A minor ginseng saponin known as ginsenoside Rk1 can inhibit the growth and survival ofhuman cancer cells; however, whether ginsenoside Rk1 inhibits HeLa cell proliferation is unknown. Methods and results: Ginsenoside Rk1 blocked HeLa cells in the G0/G1 phase in a dose-dependentmanner and inhibited cell division and proliferation. Ginsenoside Rk1 markedly also activated theapoptotic signaling pathway via caspase 3, PARP, and caspase 6. In addition, ginsenoside Rk1 increasedLC3B protein expression, indicating the promotion of the autophagy signaling pathway. Protein processingin the endoplasmic reticulum signaling pathway was downregulated in Gene Ontology (GO) andKyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, consistent with tealtimequantitative PCR and western blotting that showed YOD1, HSPA4L, DNAJC3, and HSP90AA1expression levels were dramatically decreased in HeLa cells treated with ginsenoside Rk1, with YOD1was the most significantly inhibited by ginsenoside Rk1 treatment. Conclusion: These findings indicate that the toxicity of ginsenoside Rk1 in HeLa cells can be explained bythe inhibition of protein synthesis in the endoplasmic reticulum and enhanced apoptosis, with YOD1acting as a potential target for cervical cancer treatment.

A Double-channel Four-band True Color Night Vision System

Yunfeng Jiang,Dongsheng Wu,Jie Liu,Kuo Tian,Dan Wang 한국광학회 2022 Current Optics and Photonics Vol.6 No.6

By analyzing the signal-to-noise ratio (SNR) theory of the conventional true color night vision system, we found that the output image SNR is limited by the wavelength range of the system response λ 1and λ 2 . Therefore, we built a double-channel four-band true color night vision system to expand the system response to improve the output image SNR. In the meantime, we proposed an image fusion method based on principal component analysis (PCA) and nonsubsampled shearlet transform (NSST) to obtain the true color night vision images. Through experiments, a method based on edge extraction of the targets and spatial dimension decorrelation was proposed to calculate the SNR of the obtained images and we calculated the correlation coefficient (CC) between the edge graphs of obtained and reference images. The results showed that the SNR of the images of four scenes obtained by our system were 125.0%, 145.8%, 86.0% and 51.8% higher, respectively, than that of the conventional tri-band system and CC was also higher, which demonstrated that our system can get true color images with better quality.

Displacement-based design approach for highway bridges with SMA isolators

Liu, Jin-Long,Zhu, Songye,Xu, You-Lin,Zhang, Yunfeng Techno-Press 2011 Smart Structures and Systems, An International Jou Vol.8 No.2

As a practical and effective seismic resisting technology, the base isolation system has seen extensive applications in buildings and bridges. However, a few problems associated with conventional lead-rubber bearings have been identified after historical strong earthquakes, e.g., excessive permanent deformations of bearings and potential unseating of bridge decks. Recently the applications of shape memory alloys (SMA) have received growing interest in the area of seismic response mitigation. As a result, a variety of SMA-based base isolators have been developed. These novel isolators often lead to minimal permanent deformations due to the self-centering feature of SMA materials. However, a rational design approach is still missing because of the fact that conventional design method cannot be directly applied to these novel devices. In light of this limitation, a displacement-based design approach for highway bridges with SMA isolators is proposed in this paper. Nonlinear response spectra, derived from typical hysteretic models for SMA, are employed in the design procedure. SMA isolators and bridge piers are designed according to the prescribed performance objectives. A prototype reinforced concrete (RC) highway bridge is designed using the proposed design approach. Nonlinear dynamic analyses for different seismic intensity levels are carried out using a computer program called "OpenSees". The efficacy of the displacement-based design approach is validated by numerical simulations. Results indicate that a properly designed RC highway bridge with novel SMA isolators may achieve minor damage and minimal residual deformations under frequent and rare earthquakes. Nonlinear static analysis is also carried out to investigate the failure mechanism and the self-centering ability of the designed highway bridge.

Offshore Wind Converter Reliability Evaluation

Pengcheng Zhu,Yunfeng Liu,Roesner Robert,Xin Hao 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Offshore wind turbine is facing the challenges of harsh environment and low accessibility etc. To make offshore wind business success for long-term operation, high reliability is very important to make the system get the same availability as its onshore counterparts. According to existing statistics, about 40% system faults are related to wind converters. Some of the faults are caused by improper design, and others come from worst-case operation and improper control. All these related to the converter reliability issue. To get full understanding of wind converter reliability issue, this paper introduces a systematic method that includes the converter failure model evaluation and analysis (FMEA), reliability modeling & calculation, availability calculation, reliability test design and worst-case shock simulation/evaluation. Based on these methods, a typical wind converter system is analyzed. According results and improvement instructions are presented..

Displacement-based design approach for highway bridges with SMA isolators

Jin-long Liu,Songye Zhu,You-lin Xu,Yunfeng Zhang 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.8 No.2

As a practical and effective seismic resisting technology, the base isolation system has seen extensive applications in buildings and bridges. However, a few problems associated with conventional leadrubber bearings have been identified after historical strong earthquakes, e.g., excessive permanent deformations of bearings and potential unseating of bridge decks. Recently the applications of shape memory alloys (SMA) have received growing interest in the area of seismic response mitigation. As a result, a variety of SMA-based base isolators have been developed. These novel isolators often lead to minimal permanent deformations due to the self-centering feature of SMA materials. However, a rational design approach is still missing because of the fact that conventional design method cannot be directly applied to these novel devices. In light of this limitation, a displacement-based design approach for highway bridges with SMA isolators is proposed in this paper. Nonlinear response spectra, derived from typical hysteretic models for SMA, are employed in the design procedure. SMA isolators and bridge piers are designed according to the prescribed performance objectives. A prototype reinforced concrete (RC) highway bridge is designed using the proposed design approach. Nonlinear dynamic analyses for different seismic intensity levels are carried out using a computer program called “OpenSees”. The efficacy of the displacement-based design approach is validated by numerical simulations. Results indicate that a properly designed RC highway bridge with novel SMA isolators may achieve minor damage and minimal residual deformations under frequent and rare earthquakes. Nonlinear static analysis is also carried out to investigate the failure mechanism and the self-centering ability of the designed highway bridge.

Chemical Bonds-Conjugated Ag2SO3/NaNbO3 Hybrids as Efficient Photocatalysts: In-situ Fabrication, Characterization and Degradation of Rhodamine B and Methyl Orange

Yanmei Feng,Zhiqiang Wang,Yunfeng Yang,Xiang-Feng Wu,Xiaodong Gong,Yajian Liu,Yufei Li,Zuo-Lin Cao,Chao Wang,Xin Tong 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.7

The Ag2SO3/NaNbO3 hybrids have been fabricated via a facile method at room temperature. Several methods such as X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy were used to characterize the samples. Moreover, the photocatalytic activity of the samples was assessed by degradation of rhodamine B and methyl orange under the visible light illumination. Experimental results indicated the photocatalytic degradation efficiency of the as-fabricated hybrids was first increased and then decreased with increasing the dosage of NaNbO3. When the molar ratio of Ag2SO3 to NaNbO3 was 1:0.7, the as-fabricated composites had the best photodegradation efficiency of 96.4% in 30 min for rhodamine B and 97.1% in 60 min for methyl orange, respectively. These were obviously higher than that of pure samples. Furthermore, Ag2SO3 was conjugated with NaNbO3 via chemical-bonds rather than physical contact. In addition, the possible photocatalytic degradation mechanism was also provided and the main roles during the process of photocatalytic degradation were played by holes.

Voltage Gain Neutral-Point Shifter Converter With Step-Up/Down Capability for Wide Voltage Range Application

Chen Zhangyong,Shen Lanxiao,Liu YuLang,Wu Yunfeng 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

In order to solve the problem of poor performance of traditional step-up/down converter, a novel converter with voltage gain neutral-point shifter is proposed in this paper. Compare to traditional buck-boost converter, only one series-capacitor is externally added. The coupling capacitor in proposed converter is series connected in charging power path, and therefore, the voltage stress of switches is reduced. Furthermore, when appropriately adjusting the duty cycle, half voltage stress of conventional buck-boost converter can be obtained. By using interleaved control strategy, the proposed converter has lower inductor current ripple and also has the character of higher step-down conversion ratio without any other auxiliary circuit. Moreover, the inherent current sharing character could be achieved when the duty cycle of main switch is less than 0.5. Based on these merits, the efficiency of the proposed converter can be improved. In this paper, the operational principle, the related analysis including inductor current ripple and voltage stress analysis, loss comparison analysis of the proposed converter are given. Finally, experimental prototype with 72 W is established to verify the character of the proposed converter.