A novel approach for the time-domain fluorescence imaging of a semi-infinite turbid medium: Monte Carlo evaluation

2017 ◽  
Author(s):  
Kernel Prieto ◽  
Goro Nishimura
Keyword(s):  
Monte Carlo ◽  
Fluorescence Imaging ◽  
Time Domain ◽  
Turbid Medium ◽  
Novel Approach ◽  
Monte Carlo Evaluation ◽  
The Time Domain

scholarly journals Temporal design for additive manufacturing

2020 ◽  
Vol 106 (9-10) ◽  
pp. 3849-3857
Author(s):  
S. Saliba ◽  
J. C. Kirkman-Brown ◽  
L. E. J. Thomas-Seale
Keyword(s):  
Additive Manufacturing ◽  
Time Domain ◽  
Processing Parameters ◽  
Software Pipeline ◽  
Novel Approach ◽  
Knowledge Propagation ◽  
End Use ◽  
The Time Domain ◽  
And Control ◽  
Design For Am

AbstractAdditive manufacturing (AM) is expected to generate huge economic revenue by 2025; however, this will only be realised by overcoming the barriers that are preventing its increased adoption to end-use parts. Design for AM (DfAM) is recognised as a multi-faceted problem, exasperated by constraints to creativity, knowledge propagation, insufficiencies in education and a fragmented software pipeline. This study proposes a novel approach to increase the creativity in DfAM. Through comparison between DfAM and in utero human development, the unutilised potential of design through the time domain was identified. Therefore, the aim of the research is to develop a computer-aided manufacturing (CAM) programme to demonstrate design through the time domain, known as Temporal DfAM (TDfAM). This was achieved through a bespoke MATLAB code which applies a linear function to a process parameter, discretised across the additive build. TDfAM was demonstrated through the variation of extrusion speed combined with the infill angle, through the axial and in-plane directions. It is widely accepted in the literature that AM processing parameters change the properties of AM materials. Thus, the application of the TDfAM approach offers the engineer increased creative scope and control, whilst inherently upskilling knowledge, in the design of AM materials.

scholarly journals Time- and Quantile-Varying Causality between Investor Attention and Bitcoin Returns: A Rolling-Window Causality-in-Quantiles Approach

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jianqin Hang ◽  
Xu Zhang
Keyword(s):  
Time Domain ◽  
Time Varying ◽  
Investor Attention ◽  
Causality Test ◽  
Novel Approach ◽  
Rolling Window ◽  
Causality Tests ◽  
High Volatility ◽  
The Time Domain ◽  
Quantile Causality

This study proposes a novel approach that incorporates rolling-window estimation and a quantile causality test. Using this approach, Google Trends and Bitcoin price data are used to empirically investigate the time-varying quantile causality between investor attention and Bitcoin returns. The results show that the parameters of the causality tests are unstable during the sample period. The results also show strong evidence of quantile- and time-varying causality between investor attention and Bitcoin returns. Specifically, our results show that causality appears only in high volatility periods within the time domain, and causality presents various patterns across quantiles within the quantile domain.

Simulation of Jack-Up Overturning Using the Monte Carlo Method With Artificially Increased Significant Wave Height

2010 ◽  
Author(s):  
Jo̸rgen Juncher Jensen
Keyword(s):  
Monte Carlo ◽  
Wave Height ◽  
Time Domain ◽  
Significant Wave Height ◽  
Reliability Index ◽  
Form Analysis ◽  
Significant Wave ◽  
The Mean ◽  
The Time Domain ◽  
Jack Up

It is well known from linear analyses in stochastic seaway that the mean out-crossing rate of a level r is given through the reliability index, defined as r divided by the standard deviation. Hence, the reliability index becomes inversely proportional to the significant wave height. For non-linear processes the mean out-crossing rate depends non-linearly on the response level r and a good estimate can be found using the First Order Reliability Method (FORM), see e.g. Jensen and Capul (2006). The FORM analysis also shows that the reliability index is strictly inversely proportional to the significant wave height irrespectively of the non-linearity in the system. However, the FORM analysis only gives an approximation to the mean out-crossing rate. A more exact result can be obtained by Monte Carlo simulations, but the necessary length of the time domain simulations for very low out-crossing rates might be prohibitive long. In such cases the property mentioned above for the FORM reliability index can be assumed valid in the Monte Carlo simulations making it possible to increase the out-crossing rates and thus reduced the necessary length of the time domain simulations by applying a larger significant wave height than relevant from a design point-of-view. The mean out-crossing rate thus obtained can then afterwards be scaled down to the actual significant wave height. Some previous results using this property have been presented by Tonguc and So¨ding (1986), albeit in a more empirical way. In the present paper the usefulness of this property to estimate extreme wave loads will be evaluated considering the overturning of a jack-up rig.

scholarly journals Power System Stabilizer Tuning Algorithm in a Multimachine System Based on S-Domain and Time Domain System Performance Measures

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5644
Author(s):  
Predrag Marić ◽  
Ružica Kljajić ◽  
Harold R. Chamorro ◽  
Hrvoje Glavaš
Keyword(s):  
Power Systems ◽  
Power System ◽  
Time Domain ◽  
Synchronous Generator ◽  
Pole Placement ◽  
Power System Stabilizer ◽  
Weight Functions ◽  
Novel Approach ◽  
The Time Domain ◽  
System Stabilizer

One of the main characteristics of power systems is keeping voltages within given limits, done by implementing fast automatic voltage regulators (AVR), which can raise generator voltage (i.e., excitation voltage) in a short time to ceiling voltage limits while simultaneously affecting the damping component of the synchronous generator electromagnetic torque. The efficient way to increase damping in the power system is to implement a power system stabilizer (PSS) in the excitation circuit of the synchronous generator. This paper proposes an enhanced algorithm for PSS tuning in the multimachine system. The algorithm is based on the analysis of system participation factors and the pole placement method while respecting the time domain behavior of the system after being subdued with a small disturbance. The observed time-domain outputs, namely active power, speed, and rotor angle of the synchronous generator, have been classified and validated with proposed weight functions based on the minimal square deviation between the initial values in a steady-state and all sampled values during the transitional process. The system weight function proposed in this algorithm comprises s-domain and time-domain indices and represents a novel approach for PSS tuning. The proposed algorithm performance is validated on IEEE 14-bus system with a detailed presentation of the results in a graphical and table form.

scholarly journals Time-Frequency Signal Synthesis and Its Application in Multimedia Watermark Detection

2021 ◽  
Author(s):  
Lam Le
Keyword(s):  
Time Domain ◽  
Chirp Signal ◽  
Time Frequency ◽  
Synthesis Technique ◽  
Polynomial Phase ◽  
Novel Approach ◽  
Signal Synthesis ◽  
Time Frequency Localization ◽  
The Time Domain ◽  
The Individual

A novel approach is proposed in this thesis to synthesize the time domain chirp signal from the joint time-frequency distribution (TFD). The objective is to reconstruct the original signal from its corrupted version. The new signal synthesis technique is based on the Discrete Polynomial Phase Transform (DPPT) and the TFD of the signal to be synthesized. The TFD is used to separate the mono-component signals from a multi-component signal. The DPPT is then applied on the estimated mono-components to have a final synthesized version of the individual time domain signals. The candidate TFD to be used in the synthesis technique is chosen from a group of common TFDs based on their performance with different types of signals. The criteria for the comparison are joint time-frequency localization, low susceptibility to noise, cross-term suppression and the precision of the instantaneous frequency estimated from these distributions. Smoothed Psuedo Wigner-Ville Distribution is chosen as the processing TDFD in the proposed signal synthesis technique. The proposed chirp synthesis technique is applied to detect the presence of the chirp signal embedded as a watermark message in multimedia security applications. The technique can detect the presence of chirp signals from a corrupted chirp with a bit error rate up to signal synthesis is proved to be less than that of the detection method based on the Hough Radon Transform and the proposed signal synthesis technique may also be used as an error correction tool in other applications.

scholarly journals Time-Frequency Signal Synthesis and Its Application in Multimedia Watermark Detection

2021 ◽  
Author(s):  
Lam Le
Keyword(s):  
Time Domain ◽  
Chirp Signal ◽  
Time Frequency ◽  
Synthesis Technique ◽  
Polynomial Phase ◽  
Novel Approach ◽  
Signal Synthesis ◽  
Time Frequency Localization ◽  
The Time Domain ◽  
The Individual

A novel approach is proposed in this thesis to synthesize the time domain chirp signal from the joint time-frequency distribution (TFD). The objective is to reconstruct the original signal from its corrupted version. The new signal synthesis technique is based on the Discrete Polynomial Phase Transform (DPPT) and the TFD of the signal to be synthesized. The TFD is used to separate the mono-component signals from a multi-component signal. The DPPT is then applied on the estimated mono-components to have a final synthesized version of the individual time domain signals. The candidate TFD to be used in the synthesis technique is chosen from a group of common TFDs based on their performance with different types of signals. The criteria for the comparison are joint time-frequency localization, low susceptibility to noise, cross-term suppression and the precision of the instantaneous frequency estimated from these distributions. Smoothed Psuedo Wigner-Ville Distribution is chosen as the processing TDFD in the proposed signal synthesis technique. The proposed chirp synthesis technique is applied to detect the presence of the chirp signal embedded as a watermark message in multimedia security applications. The technique can detect the presence of chirp signals from a corrupted chirp with a bit error rate up to signal synthesis is proved to be less than that of the detection method based on the Hough Radon Transform and the proposed signal synthesis technique may also be used as an error correction tool in other applications.

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