Complete post-separation of overlapping ultrasonic signals by combining hard and soft modeling

Martinsson, Jesper; Hägglund, Fredrik; Carlson, Johan E.

doi:10.1016/j.ultras.2008.03.003

Cited by 21 publications

(9 citation statements)

References 16 publications

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“…On the basis of the introduced chemical composition, internal thermodynamic solverThermo-Calc, built in the NovaFlow&Solid 4.7 system, determines characteristic temperatures (liquidus -Tliq and solidus -Tsol, beginning and end of solidification) [14]. For the AC-42000 material assumed in the studies and introduced concentrations of elements (see Tab. Table 3 Table 3.…”

Section: Thermo-physical Properties Of the Ac-42000 Alloymentioning

confidence: 99%

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Synergy of modeling processes in the area of soft and hard modeling

Sika

Hajkowski

2017

MATEC Web Conf.

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Abstract. High complexity of production processes results in more frequent use of computer systems for their modeling and simulation. Process modeling helps to find optimal solution, verify some assumptions before implementation and eliminate errors. In practice, modeling of production processes concerns two areas: hard modeling (based on differential equations of mathematical physics) and soft (based on existing data). In the paper the possibility of synergistic connection of these two approaches was indicated: it means hard modeling support based on the tools used in soft modeling. It aims at significant reducing the time in order to obtain final results with the use of hard modeling. Some test were carried out in the Calibrate module of NovaFlow&Solid (NF&S) simulation system in the frame of thermal analysis (ATAS-cup). The authors tested output values forecasting in NF&S system (solidification time) on the basis of variable parameters of the thermal model (heat conduction, specific heat, density). Collected data was used as an input to prepare soft model with the use of MLP (Multi-Layer Perceptron) neural network regression model. The approach described above enable to reduce the time of production process modeling with use of hard modeling and should encourage production companies to use it.

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Section: Thermo-physical Properties Of the Ac-42000 Alloymentioning

confidence: 99%

“…It was aimed at significant acceleration of obtaining end results from a hard model in some specific cases, not related to 3D modeling. Other cases of application of both soft and hard modeling in studies are presented in [13][14].…”

Section: Introductionmentioning

confidence: 99%

Synergy of modeling processes in the area of soft and hard modeling

Sika

Hajkowski

2017

MATEC Web Conf.

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“…Therefore, it is important to find an approach for overlapping echoes separation encountered in a wide range of applications such as military and biomedical applications, [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…Time overlapping signals are encountered when time delay between echoes is shorter than the emitted signal's duration. Overlapping is due to a combination of layer thickness or distance between reflectors [1,5].…”

Section: Introductionmentioning

confidence: 99%

Overlapping Signal Separation Method Using Superresolution Technique Based on Experimental Echo Shape

Al-Oudatallah

Abboud

Khoury

et al. 2017

Advances in Acoustics and Vibration

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Overlapping signals separation is a difficult problem, where time windowing is unable to separate signals overlapping in time and frequency domain filtering is unable to separate signals with overlapping spectra. In this work, a simulation under MATLAB is implemented to illustrate the concept of overlapping signals. We propose an approach for resolving overlapping signals based on Fourier transform and inverse Fourier transform. The proposed approach is tested under MATLAB, and the simulation results validate the effectiveness and the accuracy of the proposed approach. The approach is developed using Gerchberg superresolution technique to cope with signals with low signal-to-noise ratio. For practical work, an echo shape determination is required to apply the proposed technique. The experimental results show accurate localization of multiple targets.

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“…Methods for the separation of overlapping broadband ultrasonic signals have been suggested by various authors [2]- [4]. These analysis methods attempt to model the physical systems that would generate the received signal.…”

Section: Introductionmentioning

confidence: 99%

Separation of overlapping linear frequency modulated (LFM) signals using the fractional fourier transform

Cowell

Freear

2010

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

122

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Abstract-Linear frequency modulated (LFM) excitation combined with pulse compression provides an increase in signal to noise ratio (SNR) at the receiver. LFM signals are of longer duration than pulsed signals of the same bandwidth. Consequently, in many practical situations, maintaining temporal separation between echoes is not possible. Where analysis is performed on individual LFM signals, a separation technique is required. Time windowing is unable to separate signals overlapping in time. Frequency domain filtering is unable to separate signals with overlapping spectra. This paper describes a method to separate time overlapping LFM signals through the application of the fractional Fourier transform (FrFT), a transform operating in both time and frequency domains. A short introduction to the FrFT, its operation and calculation are presented. The proposed signal separation method is illustrated by application to a simulated ultrasound signal, created by the summation of multiple time overlapping LFM signals and the component signals recovered with ±0.6% spectral error. The results of an experimental investigation are presented where the proposed separation method is applied to time overlapping LFM signals, created by the transmission of a LFM signal through a stainless steel plate and water-filled pipe.

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Complete post-separation of overlapping ultrasonic signals by combining hard and soft modeling

Cited by 21 publications

References 16 publications

Synergy of modeling processes in the area of soft and hard modeling

Synergy of modeling processes in the area of soft and hard modeling

Overlapping Signal Separation Method Using Superresolution Technique Based on Experimental Echo Shape

Separation of overlapping linear frequency modulated (LFM) signals using the fractional fourier transform

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