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Bayesian model update for damage detection of a steel plate girder bridge

  • Xin Zhou;Feng-Liang Zhang;Yoshinao Goi;Chul-Woo Kim
    • Smart Structures and Systems
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    • v.31 no.1
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    • pp.29-43
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    • 2023
  • This study investigates the possibility of damage detection of a real bridge by means of a modal parameter-based finite element (FE) model update. Field moving vehicle experiments were conducted on an actual steel plate girder bridge. In the damage experiment, cracks were applied to the bridge to simulate damage states. A fast Bayesian FFT method was employed to identify and quantify uncertainties of the modal parameters then these modal parameters were used in the Bayesian model update. Material properties and boundary conditions are taken as uncertainties and updated in the model update process. Observations showed that although some differences existed in the results obtained from different model classes, the discrepancy between modal parameters of the FE model and those experimentally obtained was reduced after the model update process, and the updated parameters in the numerical model were indeed affected by the damage. The importance of boundary conditions in the model updating process is also observed. The capability of the MCMC model update method for application to the actual bridge structure is assessed, and the limitation of FE model update in damage detection of bridges using only modal parameters is observed.

Lateral strain-axial strain model for concrete columns confined by lateral reinforcement under axial compression

  • Hou, Chongchi;Zheng, Wenzhong
    • Structural Engineering and Mechanics
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    • v.84 no.2
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    • pp.239-251
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    • 2022
  • The use of lateral reinforcement in confined concrete columns can improve bearing capacity and deformability. The lateral responses of lateral reinforcement significantly influence the effective confining pressure on core concrete. However, lateral strain-axial strain model of concrete columns confined by lateral reinforcement has not received enough attention. In this paper, based on experimental results of 85 concrete columns confined by lateral reinforcement under axial compression, the effect of unconfined concrete compressive strength, volumetric ratio, lateral reinforcement yield strength, and confinement type on lateral strain-axial strain curves was investigated. Through parameter analysis, it indicated that with the same level of axial strain, the lateral strain slightly increased with the increase in the unconfined concrete compressive strength, but decreased with the increase in volumetric ratio significantly. The lateral reinforcement yield strength had slight influence on lateral strain-axial strain curves. At the same level of lateral strain, the axial strain of specimen with spiral was larger than that of specimen with stirrup. Furthermore, a lateral strain-axial strain model for concrete columns confined by lateral reinforcement under axial compression was proposed by introducing the effects of unconfined concrete compressive strength, volumetric ratio, confinement type and effective confining pressure, which showed good agreement with the experimental results.

A DQN-based Two-Stage Scheduling Method for Real-Time Large-Scale EVs Charging Service

  • Tianyang Li;Yingnan Han;Xiaolong Li
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.18 no.3
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    • pp.551-569
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    • 2024
  • With the rapid development of electric vehicles (EVs) industry, EV charging service becomes more and more important. Especially, in the case of suddenly drop of air temperature or open holidays that large-scale EVs seeking for charging devices (CDs) in a short time. In such scenario, inefficient EV charging scheduling algorithm might lead to a bad service quality, for example, long queueing times for EVs and unreasonable idling time for charging devices. To deal with this issue, this paper propose a Deep-Q-Network (DQN) based two-stage scheduling method for the large-scale EVs charging service. Fine-grained states with two delicate neural networks are proposed to optimize the sequencing of EVs and charging station (CS) arrangement. Two efficient algorithms are presented to obtain the optimal EVs charging scheduling scheme for large-scale EVs charging demand. Three case studies show the superiority of our proposal, in terms of a high service quality (minimized average queuing time of EVs and maximized charging performance at both EV and CS sides) and achieve greater scheduling efficiency. The code and data are available at THE CODE AND DATA.

Analyzing Gut Microbial Community in Varroa destructor-Infested Western Honeybee (Apis mellifera)

  • Minji Kim;Woo Jae Kim;Soo-Je Park
    • Journal of Microbiology and Biotechnology
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    • v.33 no.11
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    • pp.1495-1505
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    • 2023
  • The western honeybee Apis mellifera L., a vital crop pollinator and producer of honey and royal jelly, faces numerous threats including diseases, chemicals, and mite infestations, causing widespread concern. While extensive research has explored the link between gut microbiota and their hosts. However, the impact of Varroa destructor infestation remains understudied. In this study, we employed massive parallel amplicon sequencing assays to examine the diversity and structure of gut microbial communities in adult bee groups, comparing healthy (NG) and Varroa-infested (VG) samples. Additionally, we analyzed Varroa-infested hives to assess the whole body of larvae. Our results indicated a notable prevalence of the genus Bombella in larvae and the genera Gillamella, unidentified Lactobacillaceae, and Snodgrassella in adult bees. However, no statistically significant difference was observed between NG and VG. Furthermore, our PICRUSt analysis demonstrated distinct KEGG classification patterns between larval and adult bee groups, with larvae displaying a higher abundance of genes involved in cofactor and vitamin production. Notably, despite the complex nature of the honeybee bacterial community, methanogens were found to be present in low abundance in the honeybee microbiota.

Probabilistic bearing capacity assessment for cross-bracings with semi-rigid connections in transmission towers

  • Zhengqi Tang;Tao Wang;Zhengliang Li
    • Structural Engineering and Mechanics
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    • v.89 no.3
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    • pp.309-321
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    • 2024
  • In this paper, the effect of semi-rigid connections on the stability bearing capacity of cross-bracings in steel tubular transmission towers is investigated. Herein, a prediction method based on the hybrid model which is a combination of particle swarm optimization (PSO) and backpropagation neural network (BPNN) is proposed to accurately predict the stability bearing capacity of cross-bracings with semi-rigid connections and to efficiently conduct its probabilistic assessment. Firstly, the establishment of the finite element (FE) model of cross-bracings with semi-rigid connections is developed on the basis of the development of the mechanical model. Then, a dataset of 7425 samples generated by the FE model is used to train and test the PSO-BPNN model, and the accuracy of the proposed method is evaluated. Finally, the probabilistic assessment for the stability bearing capacity of cross-bracings with semi-rigid connections is conducted based on the proposed method and the Monte Carlo simulation, in which the geometric and material properties including the outer diameter and thickness of cross-sections and the yield strength of steel are considered as random variables. The results indicate that the proposed method based on the PSO-BPNN model has high accuracy in predicting the stability bearing capacity of cross-bracings with semi-rigid connections. Meanwhile, the semi-rigid connections could enhance the stability bearing capacity of cross-bracings and the reliability of cross-bracings would significantly increase after considering semi-rigid connections.

A Systematic Review of Commercial Building Greening with CiteSpace

  • Yimeng Wu;Zhendong Wang;Kai Li;Hao Wang
    • International Journal of High-Rise Buildings
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    • v.12 no.4
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    • pp.273-285
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    • 2023
  • The commercial buildings greening can generate multiple benefits to achieve a sustainable building and business environment. However, a comprehensive systematic review of commercial buildings greening across multiple disciplines has yet to be reported. This study conducted a systematic analysis of 39 literature on commercial building greening from Web of Science over the past 19 years and utilized CiteSpace to visualize the academic evolution and trends in this field. Key findings were: 1) The number of publications in the past five years has increased, indicating that commercial building greening research has received widespread attention. 2) The large number of publications means that the research field of commercial building greening is relatively broad. 3) The study of commercial building greening has become a global participation and cooperation research topic. The top cooperating countries mainly come from the United States and Europe, while the differences in cooperation between institutions in developing countries are less significant. 4) The greening of commercial buildings is more related to research on behavioral activities. 5) The research on commercial building greening has developed from architecture and plants to interdisciplinary fields, including psychology, economics, and management. 6) The cost of commercial buildings greening is generally an obstacle to installation. This study provides specific references for stakeholders and plays a crucial role in determining the evolution of commercial building greening research and predicting future research needs and opportunities.

Deriving vertical velocity in tornadic wind field from radar-measured data and improving tornado simulation by including vertical velocity at velocity inlet

  • Yi Zhao;Guirong Yan;Ruoqiang Feng;Zhongdong Duan;Houjun Kang
    • Wind and Structures
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    • v.38 no.4
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    • pp.245-259
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    • 2024
  • In a tornadic wind field, the vertical velocity component in certain regions of tornadoes can be significant, forming one of the major differences between tornadic wind fields and synoptic straight-line wind fields. To better understand the wind characteristics of tornadoes and properly estimate the action of tornadoes on civil structures, it is important to ensure that all the attributes of tornadoes are captured. Although Doppler radars have been used to measure tornadic wind fields, they can only directly provide information on quasi-horizontal velocity. Therefore, lots of numerical simulations and experimental tests in previous research ignored the vertical velocity at the boundary. However, the influence of vertical velocity in tornadic wind fields is not evaluated. To address this research gap, this study is to use an approach to derive the vertical velocity component based on the horizontal velocities extracted from the radar-measured data by mass continuity. This approach will be illustrated by using the radar-measured data of Spencer Tornado as an example. The vertical velocity component is included in the initial inflow condition in the CFD simulation to assess the influence of including vertical velocity in the initial inflow condition on the entire tornadic wind field.

The multi-axial strength performance of composited structural B-C-W members subjected to shear forces

  • Zhu, Limeng;Zhang, Chunwei;Guan, Xiaoming;Uy, Brian;Sun, Li;Wang, Baolin
    • Steel and Composite Structures
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    • v.27 no.1
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    • pp.75-87
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    • 2018
  • This paper presents a new method to compute the shear strength of composited structural B-C-W members. These B-C-W members, defined as concrete-filled steel box beams, columns and shear walls, consist of a slender rectangular steel plate box filled with concrete and inserted steel plates connecting the two long-side steel plates. These structural elements are intended to be used in structural members of super-tall buildings and nuclear safety-related structures. The concrete confined by the steel plate acts to be in a multi-axial stressed state: therefore, its shear strength was calculated on the basis of a concrete's failure criterion model. The shear strength of the steel plates on the long sides of the structural element was computed using the von Mises plastic strength theory without taking into account the buckling of the steel plate. The spacing and strength of the inserted plates to induce plate yielding before buckling was determined using elastic plate theory. Therefore, a predictive method to compute the shear strength of composited structural B-C-W members without considering the shear span ratio was obtained. A coefficient considering the influence of the shear span ratio was introduced into the formula to compute the anti-lateral bearing capacity of composited structural B-C-W members. Comparisons were made between the numerical results and the test results along with this method to predict the anti-lateral bearing capacity of concrete-filled steel box walls. Nonlinear static analysis of concrete-filled steel box walls was also conducted by using ABAQUS and the results agreed well with the experimental data.

Cloning, Expression, and Characterization of a Highly Active Alkaline Pectate Lyase from Alkaliphilic Bacillus sp. N16-5

  • Li, Gang;Rao, Lang;Xue, Yanfen;Zhou, Cheng;Zhang, Yun;Ma, Yanhe
    • Journal of Microbiology and Biotechnology
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    • v.20 no.4
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    • pp.670-677
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    • 2010
  • An alkaline pectate lyase, Bsp165PelA, was purified to homogeneity from the culture broth of alkaliphilic Bacillus sp. N16-5. The enzyme showed a specific activity as high as 1,000 U/mg and had optimum activity at pH 11.5 and $50^{\circ}C$. It was composed of a single polypeptide chain with a molecular mass of 42 kDa deduced from SDS-PAGE, and its isoelectric point was around pH 6.0. It could efficiently depolymerize polygalacturonate and pectin. Characterization of product formation revealed unsaturated digalacturonate and trigalacturonate as the main products. The pectate lyase gene (pelA) contained an open reading frame (ORF) of 1,089 bp, encoding a 36-amino acids signal peptide and a mature protein of 326 amino acids with a calculated molecular mass of 35.943 Da. The deduced amino acid sequence from the pelA ORF exhibited significant homology to those of known pectate lyases in polysaccharide lyase family 1. Some conserved active-site amino acids were found in the deduced amino acid sequence of Bsp165PelA. $Ca^{2+}$ was not required for activity on pectic substrates.

A Study on the Suits Purchasing Conditions of the Chinese Men

  • Im, Soon;Sohn, Hee-Soon;Kim, Jee-Yeon
    • Journal of Fashion Business
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    • v.5 no.5
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    • pp.87-96
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    • 2001
  • The purposes of this study is to supply information on the most common and generalized purchasing conditions of suits in China by surveying male customers from Beijing, Shanghai, Dalian, Tianjin, Harbin and Guangzhou with ages from 20's to 40's. Statistic data from the questionnaire was analyzed by SPSS 10.0 for windows and the analyzing method was processed by descriptive statistics, cross analysis and dispersed analysis and for verifying similarities, t-test and $\chi^2$-test were used. The results could be summarized as follows; First, Purchasing places for suits were stores specializing in men's wear, department stores and reasons for purchasing suits were 'For business' and 'Change of season'. Two, for purchasing information provider, television worked as the key source of providing purchasing information and outdoor advertisement, for main influence of purchasing, the consumers answered that they are the key decision makers and replied their wife or girlfriend's opinion as the answer. Three, for number of suits in possession, answered three suits followed by more than five suits and for the purchasing period, the consumers chose one suit per year or every 6month. Four, according to the questionnaire on prices, colors, fabrics and styles of suits they buy, the consumers pay between 1,000 and 1,999RMB per suit and for the colors, black, dark gray and deep blue. For the choice of fabrics, said pure wool. For the styles of the suits, answered single three buttons. Five, the result from a question on the level of satisfaction shows 'satisfied', 'average' and 'very satisfied' with the purchase.

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