Analysis of decimation techniques to improve computational efficiency of a frequency-domain evaluation approach for real-time hybrid simulation

Guo, Tong,Xu, Weijie,Chen, Cheng Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.6

Accurate actuator tracking is critical to achieve reliable real-time hybrid simulation results for earthquake engineering research. The frequency-domain evaluation approach provides an innovative way for more quantitative post-simulation evaluation of actuator tracking errors compared with existing time domain based techniques. Utilizing the Fast Fourier Transform the approach analyzes the actuator error in terms of amplitude and phrase errors. Existing application of the approach requires using the complete length of the experimental data. To improve the computational efficiency, two techniques including data decimation and frequency decimation are analyzed to reduce the amount of data involved in the frequency-domain evaluation. The presented study aims to enhance the computational efficiency of the approach in order to utilize it for future on-line actuator tracking evaluation. Both computational simulation and laboratory experimental results are analyzed and recommendations on the two decimation factors are provided based on the findings from this study.

Detection of Cucumber Powdery Mildew Based on Spectral and Image Information

Xu Ji Tong,Zhang Zhe,Guo Yu Hang,Liu Yufeng,Ning Xiao Feng 한국농업기계학회 2023 바이오시스템공학 Vol.48 No.2

Purpose The aim of this study was to fi nd the optimal detection method for cucumber powdery mildew and improve the identifi cation effi ciency. Methods Image segmentation technology was used to extract spot images and grade classifi cation of powdery mildew. The relationship between powdery mildew spot and spectral refl ectance and intensity was studied. The powdery mildew detection model was established by using qualitative analysis and quantitative prediction methods combined with greenness ( a* ) indices of cucumber leaves. Results There were strong positive correlations between greenness and spectrum in some characteristic bands. Through the extraction of disease spot images and disease classifi cation, it was found that the higher the disease grade of leaves was, the higher the spectral refl ectivity and fl uorescence intensity. In the quantitative prediction model, the R 2 of the NIR spectrum was improved (0.8742) after MSC and SPA, and the eff ect of the fl uorescence spectrum model was not ideal. In the qualitative discriminant model, KNN and ensemble subspace discriminant were obtained for two kinds of spectra, and the identifi cation accuracy of the qualitative model was 97.5% after verifi cation. Conclusion An NIR spectral model can be used for the quantitative prediction of cucumber powdery mildew. The qualitative discriminant model had high accuracy for cucumber powdery mildew.

Analysis of decimation techniques to improve computational efficiency of a frequency-domain evaluation approach for real-time hybrid simulation

Tong Guo,Chengcheng,Weijie Xu 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.6

Accurate actuator tracking is critical to achieve reliable real-time hybrid simulation results for earthquake engineering research. The frequency-domain evaluation approach provides an innovative way for more quantitative post-simulation evaluation of actuator tracking errors compared with existing time domain based techniques. Utilizing the Fast Fourier Transform the approach analyzes the actuator error in terms of amplitude and phrase errors. Existing application of the approach requires using the complete length of the experimental data. To improve the computational efficiency, two techniques including data decimation and frequency decimation are analyzed to reduce the amount of data involved in the frequency-domain evaluation. The presented study aims to enhance the computational efficiency of the approach in order to utilize it for future on-line actuator tracking evaluation. Both computational simulation and laboratory experimental results are analyzed and recommendations on the two decimation factors are provided based on the findings from this study.

Quantitative Assessment of the Effects of MMP-2 Polymorphisms on Lung Carcinoma Risk

Guo, Xiao-Tong,Wang, Jun-Feng,Zhang, Lin-You,Xu, Guang-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6

Background: Previous studies assessing associations between matrix metalloproteinase 2 (MMP-2) polymorphisms and lung cancer risk reported conflicting results. A meta-analysis was therefore performed to derive a more precise estimation. Method: Case-control studies assessing associations between MMP-2 C735T and C1306T polymorphisms and lung cancer risk were included. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated. Results: 7 studies with a total of 3,189 lung cancer cases and 3,013 controls were finally included into this meta-analysis. Overall, the MMP-2 C735T polymorphism was associated with lung cancer risk under the homozygote model (CC versus TT: OR =1.44, 95% CI = 1.03-2.02, $I^2$ = 0%), while the MMP-2 C1306T polymorphism also associated demonstrated links with all four models (all P values less than 0.05). Subgroup analyses by race suggested obvious associations between MMP-2 C735T and C1306T polymorphisms and lung cancer risk in Asians but not in Caucasians. There was no evidence for publication bias. Conclusion: Currently available evidence supports teh conclusion that MMP-2 C735T and C1306T polymorphisms influence susceptibility to lung cancer in Asians.

Low beta superconducting cavity system design for HIAF iLinac

Mengxin Xu,Yuan He,Shengxue Zhang,Lubei Liu,Tiancai Jiang,Zehua Liang,Tong Liu,Yue Tao,Chunlong Li,Qitong Huang,Fengfeng Wang,Hao Guo,Feng Bai,Xianbo Xu,Shichun Huang,Xiaoli Li,Zhijun Wang,Shenghu Zha Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7

A superconducting ion-Linac (iLinac), which is supposed to work as the injector in the High Intensity heavy-ion Accelerator Facility project, is under development at the Institute of Modern Physics (IMP), Chinese Academy of Sciences. The iLinac is a superconducting heavy ion linear accelerator approximately 100 meters long and contains 96 superconducting cavities in two types of 17 cyromodules. Two types of superconducting resonators (quarter-wave resonators with a frequency of 81.25 MHz and an optimal beta β = v/c = 0.07 called QWR007 and half-wave resonators with a frequency of 162.5 MHz and an optimal beta β = 0.15 called HWR015) have been investigated. The cavity design included extensive multi-parameter electromagnetic simulations and mechanical analysis, and its results are described in details. The fundamental power coupler and cavity dynamic tuner designs are also presented in this article. The prototypes are under manufacturing and expected to be ready in 2023.

Fishbone Oscillations in the Experimental Advanced Superconductivity Tokamak

Liqing Xu,Liqun Hu,Yi Yuan,Yingying Li,Guo-Qiang Zhong,Hai-Qing Liu,Kaiyun Chen,Tong-Hui Shi,Yan-Min Duan 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.6

A fishbone oscillation was observed in the neutral beam injection plasma at Experimental Ad- vanced Superconductivity Tokamak (EAST). This m = 1/n = 1 (m, n: poloidal, toroidal mode numbers, respectively) typical internal kink mode travels in the ion-diamagnetism direction in the poloidal section with a rotation speed close to the ion diamagnetic drift frequency. A high thermal plasma beta and high amounts of energetic ions are necessary for the mode to develop. Fishbone oscillations can expel heavy impurities in the core, which favors sustaining a high-performance plasma. The born frequency of the fishbone oscillation is the ion diamagnetic drift frequency and the chirping down of the frequency during the initial growth phase is the result of a drop in ion- diamagnetic drift frequency. The excitation energy is thought to be due to the thermal plasma pressure gradient; however, the development of a fishbone oscillation is related to energetic ions. A fishbone oscillation was observed in the neutral beam injection plasma at Experimental Advanced Superconductivity Tokamak (EAST). This m = 1/n = 1 (m, n: poloidal, toroidal mode numbers, respectively) typical internal kink mode travels in the ion-diamagnetism direction in the poloidal section with a rotation speed close to the ion diamagnetic drift frequency. A high thermal plasma beta and high amounts of energetic ions are necessary for the mode to develop. Fishbone oscillations can expel heavy impurities in the core, which favors sustaining a high-performance plasma. The born frequency of the fishbone oscillation is the ion diamagnetic drift frequency and the chirping down of the frequency during the initial growth phase is the result of a drop in ion- diamagnetic drift frequency. The excitation energy is thought to be due to the thermal plasma pressure gradient; however, the development of a fishbone oscillation is related to energetic ions.

Serum Insulin-Like Growth Factor Binding Protein 7 as a Potential Biomarker in the Diagnosis and Prognosis of Esophagogastric Junction Adenocarcinoma

Can-Tong Liu,Yi-Wei Xu,Hong Guo,Chao-Qun Hong,Xin-Yi Huang,Yu-Hao Luo,Shi-Han Yang,Ling-Yu Chu,En- Min Li,Yu-Hui Peng 거트앤리버 소화기연관학회협의회 2020 Gut and Liver Vol.14 No.6

Background/Aims: Esophagogastric junction adenocarcinoma (EJA) is a malignant tumor associated with high morbidity and has attracted increasing attention due to a rising incidence and low survival rate. Pathological biopsy is the gold standard for diagnosis, but noninvasive and effective tests are lacking, resulting in diagnoses at advanced stages. This study explored the diagnostic value of insulin-like growth factor binding protein 7 (IGFBP7) in EJA. Methods: A total of 120 EJA patients and 88 normal controls were recruited, and their serum levels of IGFBP7 were measured by enzymelinked immunosorbent assay. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic value, and Pearson chi-square analysis was used to evaluate the correlation between IGFBP7 and clinical parameters. Kaplan- Meier survival analysis was carried out to assess the effect of IGFBP7 on overall survival (OS). Results: The levels of IGFBP7 were higher in both early- and late-stage EJA patients than in normal controls (p<0.001). The area under the ROC curve for EJA patients was 0.794 (95% confidence interval [CI], 0.733 to 0.854), with a cutoff value of 2.716 ng/mL, a sensitivity of 63.3% (95% CI, 54.0% to 71.8%) and a specificity of 90.9% (95% CI, 82.4% to 95.7%). For the diagnosis of early-stage EJA, the same cutoff value and specificity were obtained, but the sensitivity of IGFBP7 was 54.3% (95% CI, 36.9% to 70.8%). Patients with low IGFBP7 protein expression had lower OS than those with high expression (p=0.034). The multivariate analysis showed that IGFBP7 is an independent prognostic factor for EJA (p=0.011). Conclusions: Serum IGFBP7 acts as a potential diagnostic and prognostic marker for EJA.

Localized evaluation of actuator tracking for real-time hybrid simulation using frequency-domain indices

Weijie Xu,Tong Guo,Cheng Chen 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.5

Accurate actuator tracking plays an important role in real-time hybrid simulation (RTHS) to ensure accurate and reliable experimental results. Frequency-domain evaluation index (FEI) interprets actuator tracking into amplitude and phase errors thus providing a promising tool for quantitative assessment of real-time hybrid simulation results. Previous applications of FEI successfully evaluated actuator tracking over the entire duration of the tests. In this study, FEI with moving window technique is explored to provide post-experiment localized actuator tracking assessment. Both moving window with and without overlap are investigated through computational simulations. The challenge is discussed for Fourier Transform to satisfy both time domain and frequency resolution for selected length of moving window. The required data window length for accuracy is shown to depend on the natural frequency and structural nonlinearity as well as the ground motion input for both moving windows with and without overlap. Moving window without overlap shows better computational efficiency and has potential for future online evaluation. Moving window with overlap however requires much more computational efforts and is more suitable for post-experiment evaluation. Existing RTHS data from Network Earthquake Engineering Simulation (NEES) is utilized to further demonstrate the effectiveness of the proposed approaches. It is demonstrated that with proper window size, FEI with moving window techniques enable accurate localized evaluation of actuator tracking for real-time hybrid simulation.

Expression of PGDH Correlates with Cell Growth in Both Esophageal Squamous Cell Carcinoma and Adenocarcinoma

Yang, Guo-Tao,Wang, Juan,Xu, Tong-Zhen,Sun, Xue-Fei,Luan, Zi-Ying Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.3

Esophageal cancer represents the fourth most common gastrointestinal cancer and generally confers a poor prognosis. Prostaglandin-producing cyclo-oxygenase has been implicated in the pathogenesis of esophageal cancer growth. Here we report that prostaglandin dehydrogenase, the major enzyme responsible for prostaglandin degradation, is significantly reduced in expression in esophageal cancer in comparison to normal esophageal tissue. Reconstitution of PGDH expression in esophageal cancer cells suppresses cancer cell growth, at least in part through preventing cell proliferation and promoting cell apoptosis. The tumor suppressive role of PGDH applies equally to both squamous cell carcinoma and adenocarcinoma, which enriches our understanding of the pathogenesis of esophageal cancer and may provide an important therapeutic target.

Experimental Study on the Mechanism of Intermittent Water and Mud Inrush Caused by Dredging and Rainfall considering Sedimentary Characteristics in Karst Tunnels

Xin Huang,Tong Wang,Zhenhao Xu,Zhengguo Zhu,Jiaqi Guo,Peng Lin,Yongchao Tian 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

The mechanism of intermittent water and mud inrush is a difficult problem faced by disaster prevention and safe construction in karst tunnels. Aiming at revealing the mechanism of intermittent water and mud inrush, we developed an integrated testing system for filling medium deposition in karst caves and intermittent water and mud inrush. By conducting a serial of laboratory experiments, we analyzed the sedimentary characteristics of the filling medium in karst caves and the catastrophic process of intermittent water and mud inrush induced by dredging and rainfall under realistic sedimentary conditions. The results show that the filling medium exhibits layered deposition characteristics, which are affected by the water circulation time, the amount of sediments carried by water and the water flow rate. The first inrush incubation time reduces with the water head increases. The critical water head and the disaster incubation time increase with the deposition height increases. Under the same conditions, the first inrush incubation time of gravel type, silt type, and clay type filling medium decrease sequentially. The results can provide a theoretical basis for preventing intermittent water and mud inrush disasters in karst tunnels.