Evaluation of Unfilled Sheath in Concrete Structures Using Response Waveform in Time Domain

The impact elastic wave method (IEW) has been applied to evaluate the thickness and internal defects of the target structure based on the dominant frequency of the response wave that is formed by the repeated reflections in the thickness direction. However, it is difficult to evaluate the size and position of the defect by IEW if the size and depth are relatively small and deep, respectively, and further, it is known that the technique is inapplicable if the target is not a plate-like structures. Therefore, the authors propose a new technique that uses Difference value as a new evaluation index to overcome the limitations of the conventional methods. Difference value shows the change of the response waveform in the time domain; it is computed by using a response waveform of the structures in sound condition as a reference. In this paper, the practicality of the Difference value is investigated by performing experiments using concrete specimens. The results of the experiments demonstrate that Difference value changes by the influence of internal defects, and Difference value evaluates the location of the relatively small defect that is difficult to evaluate by the conventional technique.

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Selection of random vibration theory procedures for the NGA-East project and ground-motion modeling

Earthquake Spectra ◽

10.1177/87552930211019052 ◽

2021 ◽

Vol 37 (1_suppl) ◽

pp. 1420-1439

Author(s):

Albert R Kottke ◽

Norman A Abrahamson ◽

David M Boore ◽

Yousef Bozorgnia ◽

Christine A Goulet ◽

...

Keyword(s):

Ground Motion ◽

Time Domain ◽

Random Vibration ◽

Amplitude Spectrum ◽

Motion Modeling ◽

Peak Response ◽

Vibration Theory ◽

Random Vibration Theory ◽

The Time Domain ◽

The Impact

Traditional ground-motion models (GMMs) are used to compute pseudo-spectral acceleration (PSA) from future earthquakes and are generally developed by regression of PSA using a physics-based functional form. PSA is a relatively simple metric that correlates well with the response of several engineering systems and is a metric commonly used in engineering evaluations; however, characteristics of the PSA calculation make application of scaling factors dependent on the frequency content of the input motion, complicating the development and adaptability of GMMs. By comparison, Fourier amplitude spectrum (FAS) represents ground-motion amplitudes that are completely independent from the amplitudes at other frequencies, making them an attractive alternative for GMM development. Random vibration theory (RVT) predicts the peak response of motion in the time domain based on the FAS and a duration, and thus can be used to relate FAS to PSA. Using RVT to compute the expected peak response in the time domain for given FAS therefore presents a significant advantage that is gaining traction in the GMM field. This article provides recommended RVT procedures relevant to GMM development, which were developed for the Next Generation Attenuation (NGA)-East project. In addition, an orientation-independent FAS metric—called the effective amplitude spectrum (EAS)—is developed for use in conjunction with RVT to preserve the mean power of the corresponding two horizontal components considered in traditional PSA-based modeling (i.e., RotD50). The EAS uses a standardized smoothing approach to provide a practical representation of the FAS for ground-motion modeling, while minimizing the impact on the four RVT properties ( zeroth moment, [Formula: see text]; bandwidth parameter, [Formula: see text]; frequency of zero crossings, [Formula: see text]; and frequency of extrema, [Formula: see text]). Although the recommendations were originally developed for NGA-East, they and the methodology they are based on can be adapted to become portable to other GMM and engineering problems requiring the computation of PSA from FAS.

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Calibration of ultrasonic hardware for enhanced total focusing method imaging

Insight - Non-Destructive Testing and Condition Monitoring ◽

10.1784/insi.2020.62.7.408 ◽

2020 ◽

Vol 62 (7) ◽

pp. 408-415

Author(s):

M Ingram ◽

A Gachagan ◽

A Nordon ◽

A J Mulholland ◽

M Hegarty

Keyword(s):

Time Domain ◽

Pressure Profile ◽

Side Lobe ◽

Destructive Testing ◽

Experimental Variation ◽

Focal Position ◽

Measured Time ◽

The Time Domain ◽

Ray Path ◽

The Impact

Experimental variation from ultrasonic hardware is one source of uncertainty in measured ultrasonic data. This uncertainty leads to a reduction in the accuracy of images generated from these data. In this paper, a quick, easy-to-use and robust methodology is proposed to reduce this uncertainty in images generated using the total focusing method (TFM). Using a 128-element linear phased array, multiple full matrix capture (FMC) datasets of a planar reflection are used to characterise the experimental variation associated with each element index in the aperture. Following this, a methodology to decouple the time-domain error associated with transmission and reception at each element index is presented. These time-domain errors are then introduced into a simulated array model used to generate the two-way pressure profile from the array. The side-lobe-to-main-lobe energy ratio (SMER) and beam offset are used to quantify the impact of these measured time-domain errors on the pressure profile. This analysis shows that the SMER is raised by more than 6 dB and the beam is offset by more than 1 mm from its programmed focal position. This calibration methodology is then demonstrated using a steel non-destructive testing (NDT) sample with three side-drilled holes (SDHs). The time delay errors from transmission and reception are introduced into the time-of-flight (TOF) calculation for each ray path in the TFM. This results in an enhancement in the accuracy of defect localisation in the TFM image.

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Design of Two Novel Dual Band-Notched UWB Antennas

International Journal of Antennas and Propagation ◽

10.1155/2012/303264 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 10

Author(s):

Bing Li ◽

Jing-song Hong

Keyword(s):

Time Domain ◽

Simple Structure ◽

The Other ◽

Ultra Wideband ◽

Dual Band ◽

Uwb Antennas ◽

Monopole Antennas ◽

Printed Monopole ◽

The Difference ◽

The Time Domain

Two novel dual band-notched ultra-wideband (UWB) printed monopole antennas with simple structure and small size are presented. The size of both antennas is25×25×0.8 mm3. The bandwidth of one of the proposed antenna can be from 2.7 GHz to 36.8 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 5.14–5.94 GHz for WLAN applications. The bandwidth of the other is ranging for 2.7 to 41.1 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 4.8–5.9 GHz for WLAN applications. Bandwidths of the antennas are about 512% and 455% wider than those of conventional band-notched UWB antennas, respectively. In addition, the time-domain characteristics of the two antennas are investigated to show the difference between both antennas.

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Application of Laplace Domain Waveform Inversion to Cross-Hole Radar Data

Remote Sensing ◽

10.3390/rs11161839 ◽

2019 ◽

Vol 11 (16) ◽

pp. 1839

Author(s):

Xu Meng ◽

Sixin Liu ◽

Yi Xu ◽

Lei Fu

Keyword(s):

Time Domain ◽

Waveform Inversion ◽

Radar Data ◽

Dominant Frequency ◽

Data Set ◽

Laplace Domain ◽

Full Waveform ◽

Highly Nonlinear ◽

The Time Domain ◽

Ground Penetrating

Full waveform inversion (FWI) can yield high resolution images and has been applied in Ground Penetrating Radar (GPR) for around 20 years. However, appropriate selection of the initial models is important in FWI because such an inversion is highly nonlinear. The conventional way to obtain the initial models for GPR FWI is ray-based tomogram inversion which suffers from several inherent shortcomings. In this paper, we develop a Laplace domain waveform inversion to obtain initial models for the time domain FWI. The gradient expression of the Laplace domain waveform inversion is deduced via the derivation of a logarithmic object function. Permittivity and conductivity are updated by using the conjugate gradient method. Using synthetic examples, we found that the value of the damping constant in the inversion cannot be too large or too small compared to the dominant frequency of the radar data. The synthetic examples demonstrate that the Laplace domain waveform inversion provide slightly better initial models for the time domain FWI than the ray-based inversion. Finally, we successfully applied the algorithm to one field data set, and the inverted results of the Laplace-based FWI show more details than that of the ray-based FWI.

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A Method for the Analysis of Interference from DME to ATCRBS in the Time Domain

Electronics ◽

10.3390/electronics8040393 ◽

2019 ◽

Vol 8 (4) ◽

pp. 393 ◽

Cited By ~ 1

Author(s):

Guofeng Jiang ◽

Yangyu Fan ◽

Hongbo Yuan ◽

Pengliang Yuan

Keyword(s):

Time Domain ◽

Traffic Control ◽

Initial Time ◽

Analysis Method ◽

Operating Modes ◽

The Monte Carlo Method ◽

The Difference ◽

The Time Domain ◽

Overlap Method ◽

Recurrence Frequency

Analysis of the coexistence of two or more types of equipment is increasingly important. However, at present studies on the analysis method in the time domain are scant. Therefore, the aim of this paper is to explore the characteristics of signals and relations between interfering and desired signals in the time domain. Based on the periodicity of a signal, this paper presents a Periodic Pulse Overlap Method (PPOM). Using PPOM to analyze the interference from Distance Measuring Equipment (DME) to Air Traffic Control Radar Beacon System (ATCRBS) in the time domain, we obtain almost the same result as that based on the Monte Carlo Method (MCM). Furthermore, we discover the measures to reduce or even avoid interference, such as changing the Pulse Recurrence Frequency (PRF), adjusting the difference of initial time, and switching the operating modes of the equipment.

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Analysis of Vehicle Longitudinal Dynamics for Longitudinal Ride Comfort

Dynamic Systems and Control, Parts A and B ◽

10.1115/imece2006-15161 ◽

2006 ◽

Cited By ~ 3

Author(s):

Shiang-Lung Koo ◽

Han-Shue Tan ◽

Masayoshi Tomizuka

Keyword(s):

Time Domain ◽

Ride Comfort ◽

Vehicle Control ◽

Switching Behavior ◽

Mode Switching ◽

Longitudinal Motion ◽

Analytical Prediction ◽

Longitudinal Model ◽

The Time Domain ◽

The Impact

Longitudinal ride comfort is one of the most crucial features to most advanced vehicle control systems. Literature review shows that the ride comfort analysis in vehicle longitudinal motion can be divided into two categories: time domain and frequency domain. Most vehicle longitudinal control designs incorporate jerk and acceleration constraints from the time-domain comfort criterion. However, the vehicle longitudinal characteristics in the frequency range important to passenger ride comfort are rarely discussed in the vehicle control literature. This paper proposes an improved vehicle longitudinal model that captures tire and suspension modes accurately and investigates the impact of these often-ignored vehicle resonant modes to ride comfort. This study shows that the "tire-mode switching behavior" affects longitudinal ride comfort of a stopping vehicle rather than the suspension. A passenger car was tested as an example, and the collected data verified the analytical prediction from the improved vehicle longitudinal model.

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Spillover effects from news to travel and leisure stocks during the COVID-19 pandemic: Evidence from the time and frequency domains

Tourism Economics ◽

10.1177/13548166211058497 ◽

2021 ◽

pp. 135481662110584

Author(s):

Ying Wang ◽

Hongwei Zhang ◽

Wang Gao ◽

Cai Yang

Keyword(s):

Frequency Domain ◽

Time Domain ◽

Spillover Effects ◽

Short Term ◽

Time Frequency ◽

Frequency Domains ◽

Media Hype ◽

The Time Domain ◽

The Impact

The impact of the COVID-19 pandemic on tourism has received general attention in the literature, while the role of news during the pandemic has been ignored. Using a time-frequency connectedness approach, this paper focuses on the spillover effects of COVID-19-related news on the return and volatility of four regional travel and leisure (T&L) stocks. The results in the time domain reveal significant spillovers from news to T&L stocks. Specifically, in the return system, T&L stocks are mainly affected by media hype, while in the volatility system, they are mainly affected by panic sentiment. This paper also finds two risk contagion paths. The contagion index and Global T&L stock are the sources of these paths. The results in the frequency domain indicate that the shocks in the T&L industry are mainly driven by short-term fluctuations. The spillovers from news to T&L stocks and among these T&L stocks are stronger within 1 month.

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Ternary coded melody as blind audio watermark

Telfor Journal ◽

10.5937/telfor2001028l ◽

2020 ◽

Vol 12 (1) ◽

pp. 28-33

Author(s):

Rustam Latypov ◽

Evgeni Stolov

Keyword(s):

Time Domain ◽

Amplitude Modulation ◽

Strong Correlation ◽

Extended Version ◽

Conference Paper ◽

Audio File ◽

B Splines ◽

A New Technique ◽

Audio Files ◽

The Time Domain

In this paper, we developed a new technique for blind embedding of ternary coded watermarks into audio files. Usage of ternary coding increases payload of the method that can be considered as an advantage against binary-coded watermarks. A well-known melody is presented as a sequence of ternary digits (trits) and is used as a watermark. This sequence is embedded into the time domain of a host audio file through amplitude modulation and B-splines. There is a version of that procedure where the clean copy of the container is necessary for extraction watermark [1]. In our approach, we exclude that container and convert the method into a blind one. The strong correlation between neighbor samples in the container is used to this end. A procedure based on neuron net is suggested for enhancement perception of ternary coded music. In this case, we exploit the correlation between samples in the watermark melody. It is supposed that a person checks the mark's existence, and he/she can recognize the melody even after significant distortions. The resistance of the technique to the most successful attacks is investigated. The paper is an extended version of the conference paper [1].

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Compensation Scheme of a 50 Ω Bond Wire Interconnect Using Time Domain Reflectometry

Journal of Microelectronics and Electronic Packaging ◽

10.4071/imaps.301 ◽

2011 ◽

Vol 8 (3) ◽

pp. 114-120

Author(s):

K. Webb ◽

H. Song

Keyword(s):

Time Domain ◽

Integrated Circuit ◽

Negative Impact ◽

Time Domain Reflectometry ◽

Physical Models ◽

High Signal ◽

Compensation Scheme ◽

Bond Wires ◽

The Time Domain ◽

The Impact

A compensation scheme that reduces the impact of the excess reactance of bond wires is introduced. From the 3D finite element code and the time domain reflectometry (TDR), physical models were evaluated and the excess reactance of the signal path was determined to optimize the compensation structure. The presented method can be employed to reduce the negative impact caused by the excess reactances in bond wires for high signal integrity integrated circuit (IC) packaging applications.

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Capsizing Performance of Dead Ship Stability for Damaged Ships

Marine Technology Society Journal ◽

10.4031/mtsj.55.1.10 ◽

2021 ◽

Vol 55 (1) ◽

pp. 115-126

Author(s):

Lifen Hu ◽

Chen Yao ◽

Wubin Li ◽

Xiangyang Wang ◽

Zhongyu Sun

Keyword(s):

Time Domain ◽

Probability Model ◽

Ship Stability ◽

Significant Development ◽

Capsizing Probability ◽

Time Calculation ◽

The Difference ◽

The Time Domain ◽

Visual Basic 6.0 ◽

Curve Solution

AbstractThis study proposes a method for combining capsizing probability and flooding process to investigate the time-domain dead ship stability of a damaged ship. It focuses on a nonlinear righting lever GZ curve solution in the following aspects: one aspect subjects the influence of damaged tanks on a hull shape to the wind and wave, and the other aspect is based on a real-time calculation of the GZ curve. According to 1‐degree-of-freedom rolling equation, the damaged capsizing probability model is established through fourth-order Runge-Kutta algorithm and Monte Carlo simulation. Also, the model solution is applied on the basis of Visual Basic 6.0 language, and the results are compared with the NAPA platform. The most significant development in this study is combining time-domain flooding process and capsizing probability calculation. To verify the proposed methods, two damaged fishery bureau vessels are used as the sample ships. Results of time-domain capsizing probability under different loading conditions are compared, and the difference and its possible reasons are analyzed.

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