Fault diagnosis method of rolling bearing using principal component analysis and support vector machine

Ying-Kui Gu,Xiao-Qing Zhou,Dong-Ping Yu,Yan-Jun Shen 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.11

To effectively extract the fault feature information of rolling bearings and improve the performance of fault diagnosis, a fault diagnosis method based on principal component analysis and support vector machine was presented, and the rolling bearings signals with different fault states were collected. To address the limitation on effectively dealing with the raw vibration signals by the traditional signal processing technology based on Fourier transform, wavelet packet decomposition was employed to extract the features of bearing faults such as outer ring flaking, inner ring flaking, roller flaking and normal condition. Compared with the previous literature on fault diagnosis using principal component analysis (PCA) and support vector machine (SVM), one-to-one and one-to-many algorithms were taken into account. Additionally, the effect of four kernel functions, such as liner kernel function, polynomial kernel function, radial basis function and hyperbolic tangent kernel function, on the performance of SVM classifier was investigated, and the optimal hype-parameters of SVM classifier model were determined by genetic algorithm optimization. PCA was employed for dimension reduction, so as to reduce the computational complexity. The principal components that reached more than 95 % cumulative contribution rate were extracted by PCA and were input into SVM and BP neural network classifiers for identification. Results show that the fault feature dimensionality of the rolling bearing is reduced from 8-dimensions to 5-dimensions, which can still characterize the bearing status effectively, and the computational complexity is reduced as well. Compared with the raw feature set, PCA has a higher fault diagnosis accuracy (more than 97 %), and a shorter diagnosis time relatively. To better verify the superiority of the proposed method, SVM classification results were compared with the results of BP neural network. It is concluded that SVM classifier achieved a better performance than BP neural network classifier in terms of the classification accuracy and time-cost.

Passive-based Bilateral Control with Varying Time Delay

Ying Gu(고염),Kil To Chong(정길도) 제어로봇시스템학회 2008 제어로봇시스템학회 국내학술대회 논문집 Vol.2008 No.10

A control scheme for teleoperation systems with varying time delay is proposed based on a passivity concept is proposed in this paper. One approach making use of the characteristic impedances is proposed to achieve a passive control. Since passive control does not mean that the system performance will be acceptable, another transmission scheme which focus on both the passive feature and the acceptable performance is configured for varying time delay in this paper. The tracking performance has been proved through the computer simulation for varying time delay bilateral teleoperation system.

Numerical Simulation and Measurement of Welding Residual Stresses in Orthotropic Steel Decks Stiffened with U-Shaped Ribs

Ying Gu,Yadong Li,Zihao Zhou,Songbo Ren,Chao Kong 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.3

This study aims to investigate the magnitude and distribution of welding residual stresses in orthotropic steel decks stiff ened with U-shaped ribs. Numerical simulation of the welding residual stresses is performed using the thermal elastic–plastic fi nite element method. The residual stresses are subsequently measured using the hole-drilling strain-gage method. Based on the results of this study, it can be determined that: (1) The longitudinal welding residual stresses ( σ z ) in the weld zones are tensile stresses, where the peak value exceeds the minimum yield strength ( f yl ); however, relatively low compressive stresses exist in the areas located far away from the welds; (2) The stress gradient in the weld zone is steep, and the widths of the areas experiencing tensile stress are narrow; (3) In the case of the upper surface of the deck, the weld that is fi rst deposited has the highest peak stress, while similar stresses are determined for the remaining welds. In the case of the lower surface of the deck, the peak stress in the weld zones is greater than that on the upper surface; (4) In the case of the weld zone of the U-shaped ribs, the tensile stresses reach up to 1.15 f yl ; however, at locations a short distance away from the welds, the σ z varies from tensile to compressive, and fi nally transforms into a small tensile stress at the base of the U-shaped ribs. In addition, the simulated and measured σ z are compared, and the deviation between them is analyzed.

Passive-based Bilateral Controller Design under Varying Time Delay

고영(Ying Gu),정길도(Kil To Chong) 대한전기학회 2009 정보 및 제어 심포지엄 논문집 Vol.2009 No.5

Bilateral teleoperation systems, connected to computer networks such as Internet have to deal with the time delay varying depending on factors such as congestion, bandwidth or distance. And the entire system is easy to become unstable due to irregular time delay. Passivity concept has been using as a framework to solve the stability problem in bilateral control of teleoperation. Acontrol scheme for teleoperation systems with varying time delay is proposed based on a passivity concept is proposed in this paper. One approach makinguse of the characteristic impedagces is proposed to achieve a passive control. Since passive control does not mean that the system performance will be acceptable, another transmission scheme which focuses on both the passive feature and the acceptable performance is configured for varying time delay in this paper. The tracking performance has been proved through the computer simulation for varying time delay bilateral teleoperation system using Matlab Simulink.

시변시간지연 시스템을 위한 수동성 양방향 원격 제어기

고영(Gu Ying),유성구(Sung Goo Yoo),정길도(Kil To Chong) 대한전자공학회 2009 電子工學會論文誌-SC (System and control) Vol.46 No.1

인터넷과 같은 네트워크 시스템에서 네트워크 혼잡, 대역폭, 거리에 따라 발생하는 시변 시간지연을 해결하는 것은 양방향 원격제어 시스템을 설계할 때 해결해야할 문제이다. 불규칙적인 시간 지연은 전체 시스템의 성능을 저하시키거나 불안정하게 만들 수 있기 때문이다. 이러한 안정성 문제를 해결하기 위해 양방향 원격 제어 시스템에서 수동성 이론이 사용되어져 왔다. 본 논문에서는 시간 지연의 변화율에 따라 전송 제어기에 시변 이득을 적용하여 수동성을 확보할 수 있는 알고리즘을 제안하였다. 그리고 시뮬레이션을 통해 제안한 시스템의 성능 결과를 보였다. Bilateral teleoperation systems, connected to computer networks such as Internet have to deal with the time delay depending on factors such as congestion, bandwidth or distance. And the entire system is easy to become unstable due to irregular time delay. Passivity concept has been using as a framework to solve the stability problem in bilateral control of teleoperation. In this paper, we present a suitable time varying gain inserted in the transmission path that can recover passivity provided a bound on the rate of change of the known delay. Simulation results are presented showing the performance of the resulting control architecture.

Machining mechanism research of glass by discrete element method

Ying Qiu,Meilin Gu,Zhi Wei 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.3

The discrete element method (DEM) is applied to glass micromachining in this study. The indentating, cutting, micro milling processare simulated by the established DEM matching the main mechanical properties of glass in three sets of standard tests. Results show thatthe vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkablefactor influencing the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thicknessper edge. Different cutting thickness, cutter shape and spindle speed largely affect the mechanism of glass.

Inhibitory effects of osteoprotegerin on osteoclast formation and function under serum-free conditions

Ying-Xiao Fu,Jian-Hong Gu,Yi-Ran Zhang,Xi-Shuai Tong,Hong-Yan Zhao,Yan Yuan,Xue-Zhong Liu,Jian-Chun Bian,Zong-Ping Liu 대한수의학회 2013 Journal of Veterinary Science Vol.14 No.4

The purpose of this study was to determine whether osteoprotegerin (OPG) could affect osteoclat differentiation and activation under serum-free conditions. Both duck embryo bone marrow cells and RAW264.7 cells were incubated with macrophage colony stimulatory factor (M-CSF) and receptor activator for nuclear factor κB ligand (RANKL) in serum-free medium to promote osteoclastogenesis. During cultivation, 0,10, 20, 50, and 100 ng/mL OPG were added to various groups of cells. Osteoclast differentiation and activation were monitored via tartrate-resistant acid phosphatase (TRAP) staining,filamentous-actin rings analysis, and a bone resorption assay. Furthermore, the expression osteoclast-related genes, such as TRAP and receptor activator for nuclear factor κB (RANK),that was influenced by OPG in RAW264.7 cells was examined using real-time polymerase chain reaction. In summary,findings from the present study suggested that M-CSF with RANKL can promote osteoclast differentiation and activation,and enhance the expression of TRAP and RANK mRNA in osteoclasts. In contrast, OPG inhibited these activities under serum-free conditions.

Pre-treatment Elevated Platelet Count Associates with HER2 Overexpression and Prognosis in Patients with Breast Cancer

Gu, Mei-Ling,Yuan, Cai-Jun,Liu, Xiao-Mei,Zhou, Yi-Chao,Di, Shu-Huan,Sun, Fei-Fei,Qu, Quan-Ying Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.13

Purpose: To research the association between pre-treatment elevated platelet count and clinicopathologic characteristics in breast cancer (BC), as well as explore the relationship between pre-treatment elevated platelet count and HER2 status and prognosis of BC patients. Materials and Methods: A retrospective cohort of BC patients who were newly diagnosed or treated by surgery only and had pathological detection results and platelet values in the Department of Oncology, the First Affiliated Hospital of Liaoning Medical College were enrolled from 1/1/2008 until 31/12/2009, and followed up until 31/12/2014. Age, thrombocyte parameters before chemotherapy and/or radiotherapy, immunohistochemical (IHM) indexes, and regional lymph node (LN) involvement and progression-free survival (PFS) were recorded. Results: A total of 447 eligible subjects were included in this research. As we analyzed, for HER2, positive and negative, the incidence rates of elevated platelet count were 25.8% and 14.7% (P<0.05). In the Cox proportional hazards model both variables were independent risk factors for BC (for HER2, OR, 0.592, 95% confidence interval, CI, 0.355 to 0.985, P=0.044;f or PLT, OR, 0.998, 95% CI, 0.996 to 1.000, P=0.042). For ER, PR, Ki67 and LN involvement, the differences were not statistically significant (P>0.05). Conclusions: In this research, pre-treatment elevated level of platelet count demostrated a significantrelationship with HER2 amplification/overexpression, and both variables significantly influenced the prognosis of BC. However, elevated platelet count did not exhibit any association with ER, PR, Ki67 and LN involvement.

Involvement of the Ca2+ signaling pathway in osteoprotegerin inhibition of osteoclast differentiation and maturation

Ying-Xiao Fu,Jian-Hong Gu,Yi Wang,Yan Yuan,Xue-Zhong Liu,Jian-Chun Bian,Zong-Ping Liu 대한수의학회 2015 Journal of Veterinary Science Vol.16 No.2

The purpose of this study was to determine whether the Ca2+ signaling pathway is involved in the ability of osteoprotegerin (OPG) to inhibit osteoclast differentiation and maturation. RAW264.7 cells were incubated with macrophage colony-stimulating factor (M-CSF) + receptor activator of nuclear factor-κB ligand (RANKL) to stimulate osteoclastogenesis and then treated with different concentrations of OPG, an inhibitor of osteoclast differentiation. The intracellular Ca2+ concentration [Ca2+]i and phosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the different treatment groups were measured by flow cytometry and Western blotting, respectively. The results confirmed that M-CSF + RANKL significantly increased [Ca2+]i and CaMKII phosphorylation in osteoclasts (p < 0.01), and that these effects were subsequently decreased by OPG treatment. Exposure to specific inhibitors of the Ca2+ signaling pathway revealed that these changes varied between the different OPG treatment groups. Findings from the present study indicated that the Ca2+ signaling pathway is involved in both the regulation of osteoclastogenesis as well as inhibition of osteoclast differentiation and activation by OPG.

Suppression of Rice Stripe Virus Replication in Laodelphax striatellus Using Vector Insect-Derived Double-Stranded RNAs

Ying Fang,Jae Young Choi,Dong Hwan Park,Min Gu Park,Jun Young Kim,Minghui Wang,Hyun Ji Kim,Woo Jin Kim,Yeon Ho Je 한국식물병리학회 2020 Plant Pathology Journal Vol.36 No.3

RNA interference (RNAi) has attracted attention as a promising approach to control plant viruses in their insect vectors. In the present study, to suppress replication of the rice stripe virus (RSV) in its vector, Laodelphax striatellus, using RNAi, dsRNAs against L. striatellus genes that are strongly upregulated upon RSV infection were delivered through a rice leaf-medi- ated method. RNAi-based silencing of peroxiredoxin, cathepsin B, and cytochrome P450 resulted in significant down regulation of the NS3 gene of RSV, achieving a transcriptional reduction greater than 73.6% at a concentration of 100 ng/μl and, possibly compromising viral replication. L. striatellus genes might play crucial roles in the transmission of RSV; transcriptional silencing of these genes could suppress viral replication in L. striatellus. These results suggest effective RNAi-based approaches for controlling RSV and provide insight into RSV-L. striatellus interactions.