scholarly journals Automated Modal Analysis for Tracking Structural Change during Construction and Operation Phases

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 927 ◽  
Author(s):  
Jun Teng ◽  
De-Hui Tang ◽  
Xiao Zhang ◽  
Wei-Hua Hu ◽  
Samir Said ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Structural Changes ◽  
Spatial Clustering ◽  
Dynamic Monitoring ◽  
Model Order ◽  
Operational Conditions ◽  
Stabilization Diagram ◽  
Scale Experiment ◽  
Artificial Neural Network Ann ◽  
Continuous Dynamic

The automated modal analysis (AMA) technique has attracted significant interest over the last few years, because it can track variations in modal parameters and has the potential to detect structural changes. In this paper, an improved density-based spatial clustering of applications with noise (DBSCAN) is introduced to clean the abnormal poles in a stabilization diagram. Moreover, the optimal system model order is also discussed to obtain more stable poles. A numerical simulation and a full-scale experiment of an arch bridge are carried out to validate the effectiveness of the proposed algorithm. Subsequently, the continuous dynamic monitoring system of the bridge and the proposed algorithm are implemented to track the structural changes during the construction phase. Finally, the artificial neural network (ANN) is used to remove the temperature effect on modal frequencies so that a health index can be constructed under operational conditions.

scholarly journals Operational Modal Analysis Based on Subspace Algorithm with an Improved Stabilization Diagram Method

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shiqiang Qin ◽  
Juntao Kang ◽  
Qiuping Wang
Keyword(s):  
Modal Analysis ◽  
Confidence Intervals ◽  
Singular Values ◽  
Operational Modal Analysis ◽  
Modal Parameter ◽  
Model Order Selection ◽  
Model Order ◽  
Diagram Method ◽  
Stochastic Subspace Identification ◽  
Stabilization Diagram

Subspace-based algorithms for operational modal analysis have been extensively studied in the past decades. In the postprocessing of subspace-based algorithms, the stabilization diagram is often used to determine modal parameters. In this paper, an improved stabilization diagram is proposed for stochastic subspace identification. Specifically, first, a model order selection method based on singular entropy theory is proposed. The singular entropy increment is calculated from nonzero singular values of the output covariance matrix. The corresponding model order can be selected when the variation of singular entropy increment approaches to zero. Then, the stabilization diagram with confidence intervals which is established using the uncertainty of modal parameter is presented. Finally, a simulation example of a four-story structure and a full-scale cable-stayed footbridge application is employed to illustrate the improved stabilization diagram method. The study demonstrates that the model order can be reasonably determined by the proposed method. The stabilization diagram with confidence intervals can effectively remove the spurious modes.

Going Beyond 3-D Imaging: Automated 3-D Montaged image Analysis of Cytological Specimens

1996 ◽  
Vol 54 ◽  
pp. 282-283
Author(s):  
Badrinath Roysam ◽  
Hakan Ancin ◽  
Douglas E. Becker ◽  
Robert W. Mackin ◽  
Matthew M. Chestnut ◽  
...  
Keyword(s):  
Image Analysis ◽  
Structural Changes ◽  
Sampling Methods ◽  
Spatial Clustering ◽  
Three Dimensional ◽  
Field Of View ◽  
Cell Counting ◽  
Depth Of Field ◽  
Tissue Cell ◽  
Tissue Organization

This paper summarizes recent advances made by this group in the automated three-dimensional (3-D) image analysis of cytological specimens that are much thicker than the depth of field, and much wider than the field of view of the microscope. The imaging of thick samples is motivated by the need to sample large volumes of tissue rapidly, make more accurate measurements than possible with 2-D sampling, and also to perform analysis in a manner that preserves the relative locations and 3-D structures of the cells. The motivation to study specimens much wider than the field of view arises when measurements and insights at the tissue, rather than the cell level are needed.The term “analysis” indicates a activities ranging from cell counting, neuron tracing, cell morphometry, measurement of tracers, through characterization of large populations of cells with regard to higher-level tissue organization by detecting patterns such as 3-D spatial clustering, the presence of subpopulations, and their relationships to each other. Of even more interest are changes in these parameters as a function of development, and as a reaction to external stimuli. There is a widespread need to measure structural changes in tissue caused by toxins, physiologic states, biochemicals, aging, development, and electrochemical or physical stimuli. These agents could affect the number of cells per unit volume of tissue, cell volume and shape, and cause structural changes in individual cells, inter-connections, or subtle changes in higher-level tissue architecture. It is important to process large intact volumes of tissue to achieve adequate sampling and sensitivity to subtle changes. It is desirable to perform such studies rapidly, with utmost automation, and at minimal cost. Automated 3-D image analysis methods offer unique advantages and opportunities, without making simplifying assumptions of tissue uniformity, unlike random sampling methods such as stereology.12 Although stereological methods are known to be statistically unbiased, they may not be statistically efficient. Another disadvantage of sampling methods is the lack of full visual confirmation - an attractive feature of image analysis based methods.

scholarly journals A new automated procedure of modal identification in operational conditions

2018 ◽  
Vol 211 ◽  
pp. 21003 ◽  
Author(s):  
Gabriele Marrongelli ◽  
Carmelo Gentile
Keyword(s):  
Parametric Identification ◽  
Modal Identification ◽  
Mode Shapes ◽  
Parameter Estimates ◽  
Reference List ◽  
Modal Parameter ◽  
Operational Conditions ◽  
Historic Masonry ◽  
Stabilization Diagram ◽  
Using Data

Structural Health Monitoring (SHM) strategies are aimed at the assessment of structural performance, using data acquired by sensing systems. Among the different available approaches, vibration-based methods - involving the automation of the modal parameter estimation (MPE) and modal tracking (MT) procedures - are receiving increasing attention. In the context of vibration-based monitoring, this paper presents an automated procedure of modal identification in operational conditions. The presented algorithms can be used to effectively manage the results obtained by any parametric identification method that involves the construction and the interpretation of stabilization diagrams. The implemented approach introduces improvements related to both the MPE and the MT tasks. The MPE procedure consists of three key steps aimed at: (1) filtering a high number of spurious poles in the stabilization diagram; (2) clustering the remaining poles that share same characteristics in term of modal parameters; (3) improving the accuracy of the modal parameter estimates. In the MT procedure the use of a simple statistical approach to define adaptive thresholds together with continuously updated dynamic reference list guarantee an efficient tracking of the most representative structural modes. The advantages obtained through the proposed procedures are exemplified using data continuously collected on the historic masonry tower of San Gottardo in Corte, located in the centre of Milan, Italy. In addition, the ability of the automated algorithms to identify contributions inherent to different vibration modes, even if they are characterized by closely-spaced frequencies and a low discriminant between mode shapes, will be described in details.

Recent advances in fecal gene detection for colorectal cancer diagnosis

2021 ◽  
Vol 15 (14) ◽  
pp. 1299-1308
Author(s):  
Siyu He ◽  
Chenglin Zhou ◽  
Hailin Peng ◽  
Mei Lin
Keyword(s):  
Colorectal Cancer ◽  
Cancer Diagnosis ◽  
Gradual Increase ◽  
Dynamic Monitoring ◽  
Gene Detection ◽  
Crc Screening ◽  
Prognostic Assessment ◽  
Advanced Stages ◽  
Continuous Dynamic Monitoring ◽  
Continuous Dynamic

There has been a gradual increase in the incidence of colorectal cancer (CRC) in recent years. Most patients lack obvious early symptoms, but are commonly in mid and advanced stages when the symptoms become evident, with rather high mortalities. Early diagnosis, treatment and recurrence monitoring are crucial to improving the recovery rate of CRC. Studies have shown that tumor-related genes can be detected in the feces of CRC patients. Owing to non-invasiveness, convenient sampling and continuous dynamic monitoring, fecal gene detection may be applicable to CRC screening, diagnosis, prognostic assessment and recurrence monitoring. Herein, we review the research advances in fecal gene detection for CRC diagnosis.

Dynamic Testing and Continuous Dynamic Monitoring of Transportation, Stadia and Energy Infrastructures

2021 ◽  
pp. 15-55
Author(s):  
Álvaro Cunha ◽  
Elsa Caetano ◽  
Filipe Magalhães ◽  
Carlos Moutinho ◽  
Sérgio Pereira
Keyword(s):  
Dynamic Testing ◽  
Dynamic Monitoring ◽  
Continuous Dynamic Monitoring ◽  
Continuous Dynamic ◽  
Energy Infrastructures

scholarly journals Dynamic monitoring and analysis of alien invasive land plants in autumn and winter in Qionghai Lake

2019 ◽  
Vol 118 ◽  
pp. 04016
Author(s):  
Lin Bai ◽  
Kun Yao ◽  
Yiying Yang ◽  
Jiaying Li ◽  
Qun Zhao
Keyword(s):  
Invasive Plants ◽  
Structural Changes ◽  
Ornamental Plants ◽  
Alien Plants ◽  
Dynamic Monitoring ◽  
Alternanthera Philoxeroides ◽  
Invasive Alien Plants ◽  
Eupatorium Adenophorum ◽  
Wide Range ◽  
Autumn And Winter

Qionghai Lake is the second largest freshwater lake in Sichuan Province. Invasive plants have damaged the ecological balance of Qionghai Lake. Regular investigation and monitoring of invasive alien plants in Qionghai Lake in autumn and winter. Study structural changes and trend changes. Mapping dynamic monitoring of the distribution of invasive plants. Upon investigation, a wide range of invasive plants with a large rits are Eupatorium Adenophorum, Lantana camara, Bidens alba(L.) DC, Alternanthera philoxeroides, Pharbitis purpurea(L.) Voisgt and Oxalis corniculata L. The introduction of the Tagetes erecta L as Ornamental plants, the proliferation occurred because of mismanagement. The number of Mirabilis jalapa L. is very small. Analysis of the way of invasive alien plants into the Qionghai Sea and the measures of prevention and control.

Comparative Thermodynamic Analysis of the Behavior of C60 and C28 Fullerenes when Heated in an Inert Medium

2020 ◽  
Vol 854 ◽  
pp. 151-157 ◽  
Author(s):  
Nikolay M. Barbin ◽  
Vasiliy P. Dan ◽  
Dmitriy I. Terentyev ◽  
Sergey G. Alexeev
Keyword(s):  
Gas Phase ◽  
Structural Changes ◽  
Molar Mass ◽  
Total Enthalpy ◽  
Thermophysical Parameters ◽  
Temperature Ranges ◽  
Volume Entropy ◽  
Energy Equilibrium ◽  
Scale Experiment ◽  
Increasing Temperature

The structural changes of condensed fullerenes C60 and C28 at a temperature increase from 200 K to 2000 K have been studied by computational methods using the TERRA software for carbon-argon systems. The processes of destruction of fullerenes C60 and C28 molecules are presented, and the temperature ranges of their thermal stability are determined: up to 1000 K and up to 400 K, respectively. The following thermophysical parameters of the C60-Ar and C28-Ar systems are considered: specific volume, entropy, total enthalpy, total internal energy, equilibrium specific heat, molar mass of the gas phase, gas constant, and mass fraction of the condensed phase. A comparative analysis of their changes with increasing temperature is carried out. The results obtained in the course of thermodynamic modeling are similar to the results of a full-scale experiment conducted under similar conditions. In the future, the obtained data can be used to determine the explosive and fire-hazardous properties of fullerenes as a dispersed solid.

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