Wind velocity simulation of spatial three-dimensional fields based on autoregressive model

Wei-cheng Gao,Yan-lei Yu 한국풍공학회 2008 Wind and Structures, An International Journal (WAS Vol.11 No.3

This paper adopts autoregressive (AR) model to simulate the wind velocity of spatial threedimensional fields in accordance with the time and space dependent characteristics of the 3-D fields. Based on the built MATLAB programming, this paper discusses in detail the issues of the AR model deduced by matrix form in the simulation and proposes the corresponding solving methods: the overrelaxation iteration to solve the large sparse matrix equations produced by large number of degrees of freedom of structures; the improved Gauss formula to calculate the numerical integral equations which integral functions contain oscillating functions; the mixed congruence and central limit theorem of Lindberg-Levy to generate random numbers. This paper also develops a method of ascertaining the rank of the AR model. The numerical examples show that all those methods are stable and reliable, which can be used to simulate the wind velocity of all large span structures in civil engineering.

Wind velocity simulation of spatial three-dimensional fields based on autoregressive model

Gao, Wei-Cheng,Yu, Yan-Lei Techno-Press 2008 Wind and Structures, An International Journal (WAS Vol.11 No.3

This paper adopts autoregressive (AR) model to simulate the wind velocity of spatial three-dimensional fields in accordance with the time and space dependent characteristics of the 3-D fields. Based on the built MATLAB programming, this paper discusses in detail the issues of the AR model deduced by matrix form in the simulation and proposes the corresponding solving methods: the over-relaxation iteration to solve the large sparse matrix equations produced by large number of degrees of freedom of structures; the improved Gauss formula to calculate the numerical integral equations which integral functions contain oscillating functions; the mixed congruence and central limit theorem of Lindberg-Levy to generate random numbers. This paper also develops a method of ascertaining the rank of the AR model. The numerical examples show that all those methods are stable and reliable, which can be used to simulate the wind velocity of all large span structures in civil engineering.

AR model-based crosstalk cancellation method for operational transfer path analysis

Wei Cheng,Yan Zhu,Xuefeng Chen,Chao Song,Le Zhang,Lin Gao,Yilong Liu,Zelin Nie,Hongrui Cao,Yang Yang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

To reduce the crosstalk effects between the signals at reference points in operational transfer path analysis (OTPA) and improve the reliability of solutions, a novel OTPA method based on auto-regressive (AR) model is proposed in this paper. The key to this method is to obtain the power spectrum by AR model for estimating the prior transmissibility function matrix. Firstly, in view of the lack of noise reduction process in conventional crosstalk cancellation method, singular value decomposition (SVD) is applied to reduce the noise of original signals. Secondly, Burg algorithm is used to calculate AR model parameters. Thirdly, auto-power spectrum and cross-power spectrum are obtained by AR model and the periodogram method respectively. Fourthly, the transmissibility function matrix is obtained by Landweber iterative method based on corrected signals at reference points. Finally, the proposed method can significantly reduce the crosstalk effects, resulting in more accurate evaluation of transfer path contributions. Generally, this study can provide accurate and reliable evidences for vibration & noise monitoring and reduction for mechanical systems, and thus benefit for the active control of vibration & noise.

Structural evaluation of an existing steel natatorium by FEM and dynamic measurement

Wei Liu,Wei-Cheng Gao,Yi Sun,Yan-Lei Yu 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.5

Based on numerical and experimental methods, a systematic structural evaluation of a steel natatorium in service was carried out in detail in this paper. Planning of inspection tasks was proposed firstly according to some national codes in China in order to obtain the economic and reliable results. The field visual inspections and static computation were conducted in turn under in-service environmental conditions. Further a three-dimensional finite element model was developed according to its factual geometry properties obtained from the field inspection. An analytical modal analysis was performed to provide the analytical modal properties. The field vibration tests on the natatorium were conducted and then two different system identification methods were used to obtain the dynamic characteristics of the natatorium. A good correlation was achieved in results obtained from the two system identification methods and the finite element method (FEM). The numerical and experimental results demonstrated that the main structure of the natatorium in its present status is safe and it still satisfies the demand of the national codes in China. But the roof system such as purlines and skeletons must be removed and rebuilt completely. Moreover the system identification results showed that field vibration test is sufficient to identify the reliable dynamic properties of the natatorium. The constructive suggestion on structural evaluation of the natatorium is that periodic assessment work must be maintained to ensure the natatorium’s safety in the future.

Relationship Between PTEN and Livin Expression and Malignancy of Renal Cell Carcinomas

Cheng, Tao,Zhang, Jian-Guo,Cheng, Yuan-He,Gao, Zhong-Wei,Ren, Xiao-Qiang Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6

Objectives: This study focused on PTEN and Livin expression and associations with malignancy in human renal clear cell carcinomas (RCCC). Methods: PTEN and Livin expression was assessed in 100 RCCC tissue samples, 50 paracarcinoma cases, and 20 normal renal tissue samples using the immunohistochemical Streptavidin proxidase (SP) method. The relationships between binding and corresponding biological characteristics, such as histological grade, lymph node metastases, and clinical stages were analyzed. Results: Positive PTEN expression in RCCC was significantly lower than in renal tissue adjacent to carcinoma tissue and normal renal tissue (P<0.01). Livin expression in the renal tissue adjacent to the carcinoma and normal renal tissues exhibited only low levels, whereas overall Livin expression in RCCC was statistically significant (P<0.01). In RCCC, PTEN expression rate gradually decreased with an increase in clinical stage, whereas that of Livin increased to statistically significant levels (P<0.01), PTEN and Livin levels being negatively correlated (r=-0.395, P<0.01). Conclusions: PTEN and Livin are important in RCCC development. The two factors combined are expected to provide indices for estimating RCCC malignancy and progression levels, as well as references for RCCC diagnosis and treatment.

Structure and bioactivity of triterpenoids from the stems of Schisandra sphenanthera

Cheng-Qin Liang,Rong-Hua Luo,Ju-Ming Yan,Yan Li,Xiao-Nian Li,Yi-Ming Shi,Shan-Zhai Shang,Zhong-Hua Gao,Liu-Meng Yang,Yong-Tang Zheng,Wei-Lie Xiao,Hong-Bin Zhang,Han Dong Sun 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.2

Two new triterpenoids, schisphendilactoneA and B (1 and 2), together with three known triterpenoids,were isolated from the stems of Schisandra sphenanthera. Their structures were elucidated by spectroscopic methods,and the absolute configuration of 1 was determined bysingle-crystal X-ray diffraction. Compound 2 showedmoderate inhibitory activity against SW480 cancer cellline, and compound 5 exhibited promising anti-HIV-1activity with EC50 value of 0.52 lg ml-1 and therapeuticindex value of 117.12.

Statistical Optimization of Medium Components for Milk-Clotting Enzyme Production by Bacillus amyloliquefaciens D4 Using Wheat Bran-an Agro-Industry Waste

( Wei Bing Zhang ),( Xiao Ling He ),( Hong Na Liu ),( Hui Yuan Guo ),( Fa Zheng Ren ),( Wei Dong Gao ),( Peng Cheng Wen ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.8

In this paper, two statistical methods were applied to optimize medium components to improve the production of the milk-clotting enzyme by Bacillus amyloliquefaciens D4. First, wheat bran juice, skim milk powder, and Na2HPO4 were shown to have significant effects on D4 enzyme production using the Plackett?Burman experimental design. Subsequently, an optimal medium was obtained using the Box?Behnken method, which consisted of 3.31 g/l of skim milk powder, 5.0 g/l of sucrose, 0.1 g/l of FeSO4?7H2O, 0.1 g/l of MgSO4?7H2O, 0.1 g/l of MnSO4?2H2O, 0.1 g/l of ZnSO4?7H2O, 1.52 g/l of Na2HPO4, and 172.45 g/l of wheat bran juice. With this optimal medium, the milk-clotting enzyme production was remarkably enhanced. The milk-clotting enzyme activity reached 3,326.7 SU/ml after incubation of 48 h, which was 1.76-fold higher than that of the basic medium, showing that the Plackett?Burman design and Box?Behnken response surface method are effective to optimize medium components, and B. amyloliquefaciens D4 possessed a high rennet-producing capacity in the optimal medium.

Detection of Powdery Mildew of Bitter Gourd Based on NIR/Fluorescence Spectra

Gao Jia Yu,Wei Dong Zheng,Wang Xiang,Tang Jin Cheng,Xu Ji Tong,Zhao Ping,Ning Xiao Feng 한국농업기계학회 2023 바이오시스템공학 Vol.48 No.3

Purpose Powdery mildew as one of the common vegetable diseases has very rapid infection. Its outbreak will bring about disastrous consequences to vegetable output; thus, it is of key importance to do rapid identifi cation and prevention of powdery mildew. Methods In this test, 100 bitter gourd leaves were collected as research samples, and the data of near-infrared spectra, fl uorescence spectra, and chromatic values L*a*b* , and the classic K-S algorithm was adopted to divide the sample sets; then, the quantitative forecasting and qualitative discrimination models were established. First, Pearson’s correlation analysis was carried out to fi nd the feasibility of taking a * as the modeling parameter, through cross-validation; the quantitative forecasting model was optimized by the PLSR (partial least squares regression) method. The model is also optimized by extracting the spectral feature bands using the continuous projection SPA method. Results The optimization results showed that the MSC + SPA + PLSR quantitative forecasting model of near-infrared spectra could eff ectively improve model precision, which was signifi cantly higher than that of fl uorescence spectra. Classifi cation Leaner was used to establish the quantitative forecasting model. Compared with the model of near-infrared spectra, the SPA + SVM qualitative discrimination model of fl uorescence spectra could improve the identifi cation precision of powdery mildew of bitter gourd as high as 98% through training. Conclusion This study proposed diff erent combination methods based on quantitative forecasting and qualitative discrimination and could provide a method and reference to the identifi cation of powdery mildew of bitter gourd.

A Rational Approximate Method to Fractional Order Systems

Yiheng Wei,Qing Gao,Cheng Peng,Yong Wang 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.6

This paper presents an approximate method for general fractional order dynamic systems. Firstly, a novel piecewise approximate method is proposed for fractional order integrator based on its frequency distributed mode. Based on the above method, an integer order approximation system is constructed to approximate a fractional order system. Theoretical analysis results show that the proposed method can achieve much better performance than the existing schemes for a given order in an interested frequency range. The advantage of the proposed method lies in that the resulting system are standard integer order system, which facilitates systematic stability analysis and controller synthesis in view of the well-developed linear or nonlinear system theory. Numerical simulations are presented to illustrate the effectiveness of the proposed approach in the end.

Common Genetic Variations in the MUC5AC Gene are Not Related to Helicobacter pylori Serologic Status

Zhou, Cheng-Jiang,Zhang, Liu-Wei,Gao, Fang,Zhang, Bin,Wang, Ying,Chen, Da-Fang,Jia, Yan-Bin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.24

Several lines of evidence suggest that MUC5AC genetic polymorphisms might confer susceptibility to H. pylori infection and therefore gastric cancer risk. We here assessed the association of common polymorphisms in the MUC5AC gene with H. pylori seroprevalence using an LD-based tagSNP approach in a north-western Chinese Han population. A total of 12 tagSNPs were successfully genotyped among 281 unrelated ethnic Han Chinese who had no cancer history, and no identifiable gastric disease or genetic disease. No significant association between any alleles, genotypes or haplotypes and H. pylori seroprevalence was observed. Our results suggest that common genetic variations in MUC5AC gene might not make a major contribution to the risk of H. pylori infection.