scholarly journals Inverse Filtering for Frequency Identification of Bridges Using Smartphones in Passing Vehicles: Fundamental Developments and Laboratory Verifications

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1190 ◽  
Author(s):  
Nima Shirzad-Ghaleroudkhani ◽  
Mustafa Gül
Keyword(s):  
Inverse Filtering ◽  
Inverse Filter ◽  
Vibration Data ◽  
Collection Device ◽  
Frequency Identification ◽  
Suspension Stiffness ◽  
Recorded Data ◽  
Filtering Technique ◽  
Data Source ◽  
Acceleration Signals

This paper puts forward a novel methodology of employing inverse filtering technique to extract bridge features from acceleration signals recorded on passing vehicles using smartphones. Since the vibration of a vehicle moving on a bridge will be affected by various features related to the vehicle, such as suspension and speed, this study focuses on filtering out these effects to extract bridge frequencies. Hence, an inverse filter is designed by employing the spectrum of vibration data of the vehicle when moving off the bridge to form a filter that will remove the car-related frequency content. Later, when the same car is moving on the bridge, this filter is applied to the spectrum of recorded data to suppress the car-related frequencies and amplify the bridge-related frequencies. The effectiveness of the proposed methodology is evaluated with experiments using a custom-built robot car as the vehicle moving over a lab-scale simply supported bridge. Nine combinations of speed and suspension stiffness of the car have been considered to investigate the robustness of the proposed methodology against car features. The results demonstrate that the inverse filtering method offers significant promise for identifying the fundamental frequency of the bridge. Since this approach considers each data source separately and designs a unique filter for each data collection device within each car, it is robust against device and car features.

scholarly journals Recovering Climate Data from Documentary Sources: A Study on the Climate in the South of Spain from 1792 to 1808

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 296 ◽  
Author(s):  
Fernando S. Rodrigo
Keyword(s):  
New Records ◽  
Weather Conditions ◽  
Southern Spain ◽  
Climate Data ◽  
The South ◽  
Documentary Sources ◽  
Recorded Data ◽  
Data Source

This work analyses new climate data on Southern Spain during the period 1792–1808. The data source is the periodical Correo Mercantil de España y sus Indias (Mercantile Mail of Spain and the Spanish Indies), which published weekly summaries of the weather conditions in Spain over this period. The study focuses on the southern provinces, providing 2788 new records, some of them corresponding to areas with no previously recorded data (Córdoba, Jaén). The analysis indicates the predominance of cold and dry winters, cold and wet springs, warm and dry summers, and variable autumn conditions, cold and humid in the western provinces while warm and dry in the eastern provinces. Some examples of these situations are discussed.

scholarly journals Fetal Death Certificates as a Source of Surveillance Data for Stillbirths with Birth Defects

2007 ◽  
Vol 122 (5) ◽  
pp. 664-669 ◽  
Author(s):  
C. Wes Duke ◽  
C.J. Alverson ◽  
Adolfo Correa
Keyword(s):  
Birth Defects ◽  
Fetal Death ◽  
Population Based ◽  
Congenital Defects ◽  
Death Certificates ◽  
Case Identification ◽  
Linkage Rate ◽  
Recorded Data ◽  
Data Source

Objective. We assessed fetal death certificates (FDCs) as a source of surveillance for stillbirths with birth defects by linkage with data from the Metropolitan Atlanta Congenital Defects Program (MACDP), a population-based birth defects surveillance system. Methods. Stillbirths with defects in MACDP were identified from 1994 through 2002 and linked to FDCs. Sensitivity of FDCs for capturing stillbirths with defects was estimated, and predictors for a case being reported were assessed. Concordance for selected variables from each data source was evaluated. Results. Two hundred twenty-four of 257 stillbirths with birth defects in MACDP were linked to an FDC (linkage rate 5 87.2%; 95% confidence interval [CI] 82.4, 91.0). Stillbirths of non-Hispanic black and Hispanic/other mothers were more likely to be issued an FDC (odds ratio [OR] 5 5.6 [95% CI 1.9, 17.0] and 14.0 [95% CI 1.7, 114.0], respectively). Cases undergoing autopsy were more likely to be issued an FDC (OR53.2; 95% CI 1.1, 8.7). Performance of an amniocentesis was poorly recorded on FDCs. The sensitivity and positive predictive value of FDCs for selected classes of defects ranged from 10% to 70% and 25% to 93%, respectively. Conclusions. Compared to FDCs, MACDP's active case identification improves the ascertainment of stillbirths with birth defects and the quality of certain recorded data.

The Practical Significance of Two-Dimensional Deconvolution in Echography

1987 ◽  
Vol 9 (2) ◽  
pp. 106-116 ◽  
Author(s):  
T.J.M. Jeurens ◽  
J.C. Somer ◽  
F.A.M. Smeets ◽  
A.P.G. Hoeks
Keyword(s):  
Dynamic Range ◽  
Power Level ◽  
Homogeneous Medium ◽  
Practical Significance ◽  
Noise Power ◽  
Two Dimensional ◽  
Inverse Filtering ◽  
Inverse Filter ◽  
Ultrasonic Beam ◽  
Rf Signals

This paper evaluates deconvolution (inverse filtering) as applied to ultrasonic imaging systems, and discusses the obstacles which are encountered employing the technique in practice. A minicomputer is used to generate artifical echo signals, simulating rf signals resulting from a set of point reflectors in a homogeneous medium, as recorded by an electronically focused group-steered linear array scanner. Two-dimensional deconvolution in combination with a Wiener noise reduction filter (i.e., a Wiener-Inverse filter) is applied to these simulated rf signals, which were contaminated with white noise. The efficacy of the Wiener-Inverse filter is defined in terms of its ability to resolve two point reflectors with a lateral spacing equal to the local −6 dB width of the ultrasonic beam. In favorable circumstances, the targets are resolved at signal-to-noise ratios (SNR) better than 20 dB, where SNR is defined as the maximum signal power divided by the average noise power level. Nonlinear effects due to quantization or signal clipping are investigated. In order to improve the resolution of an rf signal with a dynamic range of 40 dB, the input signal should be digitized at a minimum of 12 bits. The problem of signal clipping can be circumvented by oversampling. The two-dimensional Wiener-Inverse filter is defined in terms of both temporal and spatial properties of the insonification. Effects of wave diffraction give rise to a depth-dependent ultrasonic beam. As a result of a misfit of the Wiener-Inverse filter and the local properties of the ultrasonic beam, erroneous noisy texture arises in the image. Adaptation of the Wiener-Inverse filter with respect to the beam properties gives acceptable results, at the expense of a rather large computational effort.

Multichannel Structural Inverse Filtering

1984 ◽  
Vol 106 (1) ◽  
pp. 22-28 ◽  
Author(s):  
R. E. Powell ◽  
W. Seering
Keyword(s):  
Response Functions ◽  
Inverse Filtering ◽  
Inverse Filter ◽  
Vibration Measurements ◽  
Input Force ◽  
Multiple Input ◽  
Time Histories ◽  
Force Time ◽  
Value Decomposition ◽  
Pseudo Inverse

A technique has been implemented for predicting the multiple input force time histories acting on a machinery component through the use of multiple vibration measurements and a stored matrix of mechanical frequency response functions. A least squares pseudo-inverse of this transfer matrix is computed in the frequency domain using the singular value decomposition. This decomposition is used to condition the pseudo-inverse against potential singularities caused by uncertainties in the data. The constructed inverse filter is capable of separating multiple input force signals even when the vibration signals contain reverberated information from the inputs in overlapping frequency ranges. The technique has been successfully applied to a flat plate system with two inputs and up to four vibration measurements. Guidelines are suggested for reducing the effects of measurement inaccuracies on the force predictions.

scholarly journals EKSISTENSIALISME DAN ABSURDISME DALAM DRAMA KARYA PUTU WIJAYA

2017 ◽  
Vol 2 (1) ◽  
pp. 12
Author(s):  
Engkin Suwandana
Keyword(s):  
Qualitative Research ◽  
Data Collection ◽  
Data Use ◽  
Research Data ◽  
Text Data ◽  
Valid Data ◽  
Recorded Data ◽  
Data Source ◽  
Data Collection Technique ◽  
Descriptive Method

This study aims to (1) describe the existential drama Oh, Edan, and Dag Dig Dug works of Putu Wijaya which include: (a) freedom, (b) anxiety, (c) the failure, (d) the futility, (e) death, (2) describe absurdism in drama  Ah, Edan, and Dag Dig Dug by Putu Wijaya which includes: (a) suicide philosophical, (b) the nature of the symbolic,  and  (c) of tragedy and comedy. This study focuses on (1) existentialism in the drama Oh, Edan, and Dag Dig Dug  by  Putu Wijaya which include: (a) freedom, (b) anxiety, (c) the failure, (d) the futility, (e) death and (2) absurdism in drama Ah, Edan, and Dag Dig Dug. This study is qualitative research, using descriptive qualitative research data collection. Descriptive method is a method which seeks to describe a phenomenon, the events that occurred at that time. In this study, descriptive method is used  to describe the concept of existentialism and absurdism. This research data  use  existantialism theory  and absurdism in playwrights  by PutuWijaya. By using the technique with  the  data source in the form of three plays, the relevant data collection technique is a technique read. Reading the drama text data collection activities conducted by member’s attention totally focused on the object. Reading and listening is a set of techniques to obtain valid data followed by activities recorded data. This study concluded five concepts of existentialism and three concepts of absurdism. The results showed that existentialism in the drama Oh, Edan, Dag Dig Dug by Putu Wijaya, looked  in terms of freedom, anxiety, failure, futility, and  death.  Three absurdism concepts  in drama Ah, Edan, Dag Dig Dug  by  Putu Wijaya looked through suicide philosophical, symbolic nature, tragedy and comedy.

scholarly journals An Enhanced Inverse Filtering Methodology for Drive-By Frequency Identification of Bridges Using Smartphones in Real-Life Conditions

Smart Cities ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 499-513
Author(s):  
Nima Shirzad-Ghaleroudkhani ◽  
Mustafa Gül
Keyword(s):  
Surface Roughness ◽  
Smart Cities ◽  
Real Life ◽  
Cost Effective ◽  
Vehicle Speed ◽  
Inverse Filtering ◽  
Novel Approach ◽  
Life Scale ◽  
Frequency Identification ◽  
Speed Effect

This paper develops an enhanced inverse filtering-based methodology for drive-by frequency identification of bridges using smartphones for real-life applications. As the vibration recorded on a vehicle is dominated by vehicle features including suspension system and speed as well as road roughness, inverse filtering aims at suppressing these effects through filtering out vehicle- and road-related features, thus mitigating a few of the significant challenges for the indirect identification of the bridge frequency. In the context of inverse filtering, a novel approach of constructing a database of vehicle vibrations for different speeds is presented to account for the vehicle speed effect on the performance of the method. In addition, an energy-based surface roughness criterion is proposed to consider surface roughness influence on the identification process. The successful performance of the methodology is investigated for different vehicle speeds and surface roughness levels. While most indirect bridge monitoring studies are investigated in numerical and laboratory conditions, this study proves the capability of the proposed methodology for two bridges in a real-life scale. Promising results collected using only a smartphone as the data acquisition device corroborate the fact that the proposed inverse filtering methodology could be employed in a crowdsourced framework for monitoring bridges at a global level in smart cities through a more cost-effective and efficient process.

Sign in / Sign up

Export Citation Format

Share Document