Bayesian FEM Updating of a Long-Span Suspension Bridge Utilizing Hybrid Monte Carlo Simulation and Kriging Predictor

Jian-Xiao Mao,Hao Wang,Jian Li 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.2

Bayesian model updating technique has been widely investigated and utilized in the field of finite element model (FEM) updating for its advantages in system uncertainty quantification. Most existing studies focus on numerical and experimental models. More studies on large-scale civil infrastructures based on field monitoring are still required. A case study on Bayesian FEM updating of the Runyang Suspension Bridge (RSB), a long-span suspension bridge with a main span of 1,490 m, is carried out in this paper. The Bayesian updating method is utilized to update the initial FEM of RSB, aiming to make the numerical modal properties match the field monitoring results. Two stochastic sampling algorithms, i.e., the Metropolis-Hastings (MH) algorithm and the Hybrid Monte Carlo (HMC) algorithm, are respectively investigated to show their advantages and limitations in Bayesian updating. Subsequently, based on the experimentalsamples generated by the Latin hypercube sampling algorithm, a Kriging predictor is established as a surrogate model to reduce the computational burden of model updating. Results show that the HMC algorithm could guarantee much higher acceptance rate of the sampled chain than the MH algorithm especially when the updating step size is large. In addition, combined with the Kriging predictor, Bayesian model updating method could serve as an effective and efficient tool to calibrate the FEM of large-scale civil infrastructures.

A Noninvasive Online System for Biomass Monitoring in Shaker Flasks Using Backward Scattered Light

Jian Mao,Yingge Yan,Olaf Eichstädt,Xianshuai Chen,Zuowei Wang,Jinming Cui 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.2

This paper presents a noninvasive optical sensor system for monitoring cell growth in shaker flasks commonly used in biological laboratories. The system uses an open-source microprocessor board to monitor concentration of Escherichia coli host cells. To allow measurement for a range of filling degrees and shaker speeds, the backscattering angle is chosen to minimize interference from surface reflections and the measurement window is synchronized to the position of the shaker flask. A nonlinear calibration model of scattered light can predict offline optical density with a mean relative error of 5.2%, an accuracy which is comparable to the classical offline method and sufficient for biotechnology applications.

Gaussian mixture model for automated tracking of modal parameters of long-span bridge

Jian-Xiao Mao,Hao Wang,Billie F. Spencer Jr. 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.2

Determination of the most meaningful structural modes and gaining insight into how these modes evolve are important issues for long-term structural health monitoring of the long-span bridges. To address this issue, modal parameters identified throughout the life of the bridge need to be compared and linked with each other, which is the process of mode tracking. The modal frequencies for a long-span bridge are typically closely-spaced, sensitive to the environment (e.g., temperature, wind, traffic, etc.), which makes the automated tracking of modal parameters a difficult process, often requiring human intervention. Machine learning methods are well-suited for uncovering complex underlying relationships between processes and thus have the potential to realize accurate and automated modal tracking. In this study, Gaussian mixture model (GMM), a popular unsupervised machine learning method, is employed to automatically determine and update baseline modal properties from the identified unlabeled modal parameters. On this foundation, a new mode tracking method is proposed for automated mode tracking for long-span bridges. Firstly, a numerical example for a three-degree-of-freedom system is employed to validate the feasibility of using GMM to automatically determine the baseline modal properties. Subsequently, the field monitoring data of a long-span bridge are utilized to illustrate the practical usage of GMM for automated determination of the baseline list. Finally, the continuously monitoring bridge acceleration data during strong typhoon events are employed to validate the reliability of proposed method in tracking the changing modal parameters. Results show that the proposed method can automatically track the modal parameters in disastrous scenarios and provide valuable references for condition assessment of the bridge structure.

Variability analysis on modal parameters of Runyang Bridge during Typhoon Masta

Jian-Xiao Mao,Hao Wang,Zhi-Xiang Xun,Zhong-Qin Zou 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.19 No.6

The modal parameters of the deck of Runyang Suspension Bridge (RSB) as well as their relationships with wind and temperature are studied based on the data recorded by its Structural Health Monitoring System (SHMS). Firstly, frequency analysis on the vertical responses at the two sides of the deck is carried out to distinguish the vertical and torsional vibration modes. Then, the vertical, torsional and lateral modal parameters of the deck of RSB are identified using Hilbert-Huang Transform (HHT) and validated by the identified results before RSB was opened to traffic. On the basis of this, the modal frequencies and damping ratios of RSB during the whole process of Typhoon Masta are obtained. And the correlation analysis on the modal parameters and wind environmental factors is then conducted. Results show that the HHT can achieve an accurate modal identification of RSB and the damping ratios show an obvious decay trend as the frequencies increase. Besides, compared to frequencies, the damping ratios are more sensitive to the environmental factors, in particular, the wind speed. Further study on configuring the variation law of modal parameters related with environmental factors should be continued.

Soil and ribbed concrete slab interface modeling using large shear box and 3D FEM

Qian, Jian-Gu,Gao, Qian,Xue, Jian-feng,Chen, Hong-Wei,Huang, Mao-Song Techno-Press 2017 Geomechanics & engineering Vol.12 No.2

Cast in situ and grouted concrete helical piles with 150-200 mm diameter half cylindrical ribs have become an economical and effective choice in Shanghai, China for uplift piles in deep soft soils. Though this type of pile has been successful used in practice, the reinforcing mechanism and the contribution of the ribs to the total resistance is not clear, and there is no clear guideline for the design of such piles. To study the inclusion of ribs to the contribution of shear resistance, the shear behaviour between silty sand and concrete slabs with parallel ribs at different spacing and angles were tested in a large direct shear box ($600mm{\times}400mm{\times}200mm$). The front panels of the shear box are detachable to observe the soil deformation after the test. The tests were modelled with three-dimensional finite element method in ABAQUS. It was found that, passive zones can be developed ahead of the ribs to form undulated failure surfaces. The shear resistance and failure mode are affected by the ratio of rib spacing to rib diameter. Based on the shape and continuity of the failure zones at the interface, the failure modes at the interface can be classified as "punching", "local" or "general" shear failure respectively. With the inclusion of the ribs, the pull out resistance can increase up to 17%. The optimum rib spacing to rib diameter ratio was found to be around 7 based on the observed experimental results and the numerical modelling.

Prostate Cancer Risk in Relation to a Single Nucleotide Polymorphism in the Insulin-like Growth Factor-binding Protein-3 (IGFBP3) Gene: a Meta-analysis

Mao, Ye-Qing,Xu, Xin,Lin, Yi-Wei,Chen, Hong,Hu, Zheng-Hui,Xu, Xiang-Lai,Zhu, Yi,Wu, Jian,Zheng, Xiang-Yi,Qin, Jie,Xie, Li-Ping Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.12

Insulin-like growth factor-binding protein-3 (IGFBP3) has been identified as a putative tumor suppressor with multifunctional roles in the IGF axis. Recently, there have been a growing body of studies investigating the relation between the IGFBP3 A-202C polymorphism, circulating IGFBP3 and prostate cancer risk, but their outcomes varied leading to controversy. Hence, it is necessary to perform a meta-analysis covering all eligible studies to shed a light on the association of IGFBP3 A-202C and cancer risk. Finally, we included a total of 11 relevant articles between 2003 and 2010 covering 14 case-control studies including 9,238 cases and 8,741 controls for our analysis. Our results showed that A-202C was a marginal risk factor of prostate cancer (allele contrast: OR=1.08, 95% CI :1.01-1.16; dominant model: OR=1.11, 95% CI :1.01-1.22; heterozygote codominant model: OR=1.11, 95% CI :1.03-1.18; homozygote contrast: OR=1.19, 95% CI :1.03-1.37). Stratification analysis revealed that sample size and control source were two major heterogeneous meta-factors especially in the recessive model (source: Population-based control group :p=0.30,I2=16.7%, Hospital-based control group: p=0.20, I2=30.3%; sample size: Small: p=0.22,I2= 32.8%, Medium: p=0.09,I2=48%, Large p=0.60,I2=0.0%); However, contrary to previous findings, no significance was found in racial subgroups. No significant publication bias was found in our analysis. Considering the robustness of the results and the discrepancy among some studies, there might be some unsolved confounding factors, and further more critical large studies are needed for confirmation.

Association between the XRCC3 Thr241Met Polymorphism and Breast Cancer Risk: an Updated Meta-analysis of 36 Case-control Studies

Mao, Chang-Fei,Qian, Wen-Yi,Wu, Jian-Zhong,Sun, Da-Wei,Tang, Jin-Hai Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16

Background: The X-ray repair cross-complementing group 3 (XRCC3) is a highly suspected candidate gene for cancer susceptibility. Attention has been drawn upon associations of the XRCC3 Thr241Met polymorphism with breast cancer risk. However, the previous published findings remain controversial. Hence, we performed a meta-analysis to accurately evaluate any association between breast cancer and XRCC3 T241M (23, 812 cases and 25, 349 controls) in different inheritance models. Materials and Methods: PubMed and Web of Science databases were searched systematically until December 31, 2013 to obtain all the records evaluating the association between the XRCC3 Thr241Met polymorphism and breast cancer risk. Crude odds ratios (ORs) together with 95% confidence intervals (CIs) were used to assess the strength of associations. Results: When all eligible studies were pooled into the meta analysis of XRCC3 T241M polymorphism, a significantly increased breast cancer risk was observed in heterozygote comparison (OR=1.06, 95%CI=1.01-1.12). No significant associations were found in other models. In subgroup analysis, this polymorphism seemed to be associated with elevated breast risk in Asians. No publication bias was detected. Conclusions: This meta-analysis suggests that the T241M polymorphism confers a weakly increased breast cancer risk. A study with the larger sample size is needed to further evaluate gene-gene and gene-environment interactions of the XRCC3 T241M polymorphism with breast cancer risk.

A putative pathogen-resistant regulatory pathway between MicroRNAs and candidate target genes in maize

Jian Gao,Mao Luo,Chun Zhang,Hua Peng,Haijian Lin,Yaou shen,Maojun Zhao,Guangtang Pan,Zhiming Zhang 한국식물학회 2015 Journal of Plant Biology Vol.58 No.4

MicroRNAs (miRNAs) are a family of small non-coding RNAs that, in most cases, negatively regulate gene expression at the post-transcriptional level. Plant miRNAs have been implicated in developmental processes and adaptation to environmental stress including biotic and abiotic stresses. Here, we report a comprehensive analysis of miRNAs and associated target genes under banded leaf and sheath blight (BLSB) stress caused by R. solani in maize. Eight differentially expressed miRNAs were randomly selected from deep sequencing results and validated by qRT-PCR together with their putative target genes, most of which are transcription factors as well as metabolic genes involved in auxin signaling. The results revealed that majorities of the analyzed miRNAs show an inverse correlation with their corresponding predicted target genes. In addition, a putative regulatory network of miRNAs-mRNAs responsive to R. solani was constructed. This study provides insight into the regulatory functions of miRNAs, thereby expanding our knowledge of the molecular mechanisms of pathogen resistance.

Temperature-dependent development of Lista haraldusalis (Walker) (Lepidoptera: Pyralidae) on Platycarya strobilacea

Jian-Feng Liu,Man Liu,Mao-Fa Yang,Dimitris C. Kontodimas,Xiao-Fei Yu,Qi-Xian Lian 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.4

The effect of constant temperatures on development and survival of Lista haraldusalis (Walker) (Lepidoptera:Pyralidae), a newly reported insect species used to produce insect tea in Guizhou province (China), was studiedin laboratory conditions at seven temperatures (19 °C, 22 °C, 25 °C, 28 °C, 31 °C, 34 °C, and 37 °C) on Platycaryastrobilacea. Increasing the temperature from 19 °C to 31 °C led to a significant decrease in the developmentaltime from egg to adult emergence, and then the total developmental time increased at 34 °C. Egg incubationwas the stage where L. haraldusalis experienced the highest mortality at all temperatures. The survival ofL. haraldusalis was significantly higher at 25 °C and 28 °C, whereas none of the eggs hatched at 37 °C. Commonand Ikemoto linear models were used to describe the relationship between the temperature and the developmentalrate for each immature stage of L. haraldusalis. The estimated values of the lower temperature thresholdand thermal constant of the total immature stages using Common and Ikemoto linear models were 11.34 °C and11.20 °C, and 939.85 and 950.41 degree-days, respectively. Seven nonlinear models were used to fit the experimentaldata to estimate the developmental rate of L. haraldusalis. Based on the biological significance for modelevaluation, Ikemoto linear, Logan-6, and SSI were the best models that fitted each immature stage ofL. haraldusalis and they were used to estimate the temperature thresholds. These thermal requirements and temperaturethresholds are crucial for facilitating the development of factory-based mass rearing of L. haraldusalis.

Structure-based functional site recognition for p21-activated kinase 4

Jian Wang,Gang Wang,Yu Sha,Dong-Mei Zhao,Feng Li,Mao-Sheng Cheng 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.12

Recently, many molecular modeling methodsare being developed to better understand the principlesunderlying protein folding. In the present study, fullyflexible dinucleotides d(pApA), d(pApC), d(pApG),d(pApT), d(pCpA), d(pCpC), d(pCpG), d(pCpT), d(pGpA),d(pGpC), d(pGpG), d(pGpT), d(pTpA), d(pTpC), d(pTpG)and d(pTpT) were docked onto the surface of p21-activatedkinase 4 (PAK4) kinase domain. The results showedthat automated docking was a useful tool to identify thefunctional sites of PAK4 and it may provide a theoreticalbasis for the interaction data obtained from previousexperiments. Therefore, structure-based docking with fullyflexible dinucleotide probes might be a good tool to predictand annotate the functional sites of enzymes.