scholarly journals Development of a Reference-Free Indirect Bridge Displacement Sensing System

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5647
Author(s):  
Jongbin Won ◽  
Jong-Woong Park ◽  
Junyoung Park ◽  
Junsik Shin ◽  
Minyong Park
Keyword(s):  
Estimation Method ◽  
Reference Points ◽  
Maximum Displacement ◽  
Moving Vehicle ◽  
Displacement Estimation ◽  
Sensing System ◽  
Girder Bridges ◽  
Sensor Platform ◽  
Load Carrying ◽  
Vehicle Loads

Bridge displacement measurements are important data for assessing the condition of a bridge. Measuring bridge displacement under moving vehicle loads is helpful for rating the load-carrying capacity and evaluating the structural health of a bridge. Displacements are conventionally measured using a linear variable differential transformer (LVDT), which needs stable reference points and thus prohibits the use of this method for measuring displacements for bridges crossing sea channels, large rivers, and highways. This paper proposes a reference-free indirect bridge displacement sensing system using a multichannel sensor board strain and accelerometer with a commercial wireless sensor platform (Xnode). The indirect displacement estimation method is then optimized for measuring the structural displacement. The performance of the developed system was experimentally evaluated on concrete- and steelbox girder bridges. In comparison with the reference LVDT data, the maximum displacement error for the proposed method was 2.17%. The proposed method was successfully applied to the displacement monitoring of a tall bridge (height = 20 m), which was very difficult to monitor using existing systems.

A Method of Reinforcement and Vibration Reduction of Girder Bridges Using Shape Memory Alloy Cables

2017 ◽  
Vol 17 (07) ◽  
pp. 1750076 ◽  
Author(s):  
Ai-Rong Liu ◽  
Chun-Hui Liu ◽  
Ji-Yang Fu ◽  
Yong-Lin Pi ◽  
Yong-Hui Huang ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Traffic Safety ◽  
Torsional Rigidity ◽  
Vibration Reduction ◽  
Torsional Vibrations ◽  
Moving Vehicle ◽  
Girder Bridges ◽  
Fe Simulations ◽  
Vehicle Loads

Bending and torsional vibrations caused by moving vehicle loads are likely to affect the traffic safety and comfort for girder bridges with limited torsional rigidity. This paper studies the use of cables made of shape memory alloy (SMA) as the devices of reinforcement and vibration reduction for girder bridges. The SMA cables are featured by their small volume, expedient installation. To investigate their effect on the vibration of girder bridges, theoretical analysis, numerical simulation and experimental study were conducted in this paper. For bending vibration, the governing equations of the girder with and without SMA cables subjected to moving vehicle loads were derived, while for torsional vibration, the finite element (FE) simulations were used instead. The results of bending and torsional vibrations obtained by the analytical approach and FE simulations, respectively, were compared with the experimental ones from model testing. It was confirmed that the SMA cables can restrain the vibration of the girder bridge effectively.

scholarly journals Video Analytic Based Health Monitoring for Driver in Moving Vehicle by Extracting Effective Heart Rate Inducing Features

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Kanghyu Lee ◽  
David K. Han ◽  
Hanseok Ko
Keyword(s):  
Heart Rate ◽  
Estimation Method ◽  
Region Of Interest ◽  
Ensemble Empirical Mode Decomposition ◽  
Superior Performance ◽  
Indoor Environments ◽  
Vehicle Interior ◽  
Moving Vehicle ◽  
Ambient Lighting ◽  
Driving Conditions

We propose a novel remote heart rate (HR) estimation method using facial images based on video analytics. Most of previous methods have been demonstrated in well-controlled indoor environments. In contrast, this paper proposes a practical video analytic framework under actual driving conditions by extracting key HR inducing features. In particular, when cars are driven, effective and stable HR estimation becomes challenging as there are many dynamic elements, such as rapid illumination changes, vibrations, and ambient lighting that can exist in the vehicle interior. To overcome those disturbances of HR estimation, the driver face region is first detected and cropped to the region of interest (RoI). Second, the components related to HR are extracted from mixed noisy components using ensemble empirical mode decomposition (EEMD). Finally, the extracted signal is analyzed in frequency domain and smoothed with temporal filtering. To verify our approach, the proposed method is compared with recent prominent methods employing a public HCI dataset. It has been demonstrated that the proposed approach delivers superior performance under driving conditions using Bland-Altman plots.

Analytical study on repair method for steel I-girder bridges with corrosion damage considering its structural system behavior

2021 ◽  
Author(s):  
Ryoga Oura ◽  
Takashi Yamaguchi ◽  
Kentaro Arimura
Keyword(s):  
Carrying Capacity ◽  
Corrosion Damage ◽  
Load Carrying Capacity ◽  
Structural Members ◽  
Structural System ◽  
System Behavior ◽  
Girder Bridges ◽  
Load Carrying ◽  
Girder Bridge ◽  
The Individual

<p>Bridges are composed by many structural members which interact with each other to resist against various load combinations. Considering damage repair of one of its structural members, the relationship between the recovery of the individual load-carrying capacity due to the repair of a single member and the improvement of the load-carrying capacity of the structural system is not clear. In the present study, a full-scale FE analysis has been conducted for a steel I-girder bridge system with corrosion damages which have been repaired. The analysis considered, the structural system behavior, varying the repaired areas and the type of patch members. From the analytical results, it was found that, compared to the method in which the damaged portion is completely repaired, the amount of repair can be reduced by taking into account the structural system behavior and partially repair both the damaged and the adjacent intact girders.</p>

scholarly journals A Mobile Sensing System for UrbanPM2.5Monitoring with Adaptive Resolution

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Hongjie Guo ◽  
Guojun Dai ◽  
Jin Fan ◽  
Yifan Wu ◽  
Fangyao Shen ◽  
...  
Keyword(s):  
Air Quality ◽  
Meteorological Data ◽  
Computational Cost ◽  
Estimation Method ◽  
Mobile Sensing ◽  
Prototype System ◽  
Adaptive Grids ◽  
Sensing System ◽  
Adaptive Resolution ◽  
Wide Range

This paper develops a mobile sensing system, the first system used in adaptive resolution urban air quality monitoring. In this system, we employ several taxis as sensor carries to collect originalPM2.5data and collect a variety of datasets, including meteorological data, traffic status data, and geographical data in the city. This paper also presents a novel method AG-PCEM (Adaptive Grid-Probabilistic Concentration Estimation Method) to infer thePM2.5concentration for undetected grids using dynamic adaptive grids. We gradually collect the measurements throughout a year using a prototype system in Xiasha District of Hangzhou City, China. Experimental data has verified that the proposed system can achieve good performance in terms of computational cost and accuracy. The computational cost of AG-PCEM is reduced by about 40.2% compared with a static grid method PCEM under the condition of reaching the close accuracy, and the accuracy of AG-PCEM is far superior as widely used artificial neural network (ANN) and Gaussian process (GP), enhanced by 38.8% and 14.6%, respectively. The system can be expanded to wide-range air quality monitor by adjusting the initial grid resolution, and our findings can tell citizens actual air quality and help official management find pollution sources.

Recent Developments in Japanese Flaw Assessment Methods of WES 2805

2008 ◽  
Author(s):  
Yukito Hagihara ◽  
Masayoshi Kurihara ◽  
Hitoshi Yoshinari ◽  
Takashi Miyata
Keyword(s):  
Welded Joints ◽  
Large Scale ◽  
Welded Joint ◽  
Estimation Method ◽  
Assessment Methods ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Design Curve ◽  
Load Carrying ◽  
Recent Developments

The standard for the method of assessment for flaws in the welded joints of WES 2805 was first published in 1976 and was revised in 1980 and 1997. A further revision has been carried out by the technical committee of FTS in the Japan Welding Engineering Society and the revision was completed in 2007. The standard of WES 2805 is based on a CTOD (crack tip opening displacement) design curve approach for brittle fracture, and is used for the assessment of the significance of flaws in a stress concentrated region, where large scale yielding takes place. Main topics for the recent developments for flaw assessment methods are described in this paper. These are the interaction criterion of multiple flaws, fatigue crack growth laws, determination of equivalent crack length and strain due to stress concentration, estimation method of the critical CTOD from Charpy energy and proposal of partial safety factors. In order to examine the effectiveness of the standard, extensive 2-D and 3-D FE analyses are performed for various welded joints such as a load-carrying fillet welded joint, a non-load-carrying fillet welded joint and a box welded joint. Some of them are introduced in this paper. Their analytical results indicate that the present CTOD design curve method gives a reasonable evaluation.

scholarly journals Biomass limit reference points are sensitive to estimation method, time‐series length and stock development

2020 ◽  
Vol 22 (1) ◽  
pp. 18-30
Author(s):  
Mikael Deurs ◽  
Mollie E. Brooks ◽  
Martin Lindegren ◽  
Ole Henriksen ◽  
Anna Rindorf
Keyword(s):  
Time Series ◽  
Estimation Method ◽  
Reference Points ◽  
Series Length
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