# Special Issue on Modelling, Simulation and Data Analysis in Acoustical Problems
## 2 Modelling, Simulation and Data Analysis in Acoustical Problems  
As stated in the introduction, the need of models in acoustical problems is very large and can interest many subareas of acoustics. Withstanding this variety of possible applications and considering the interdisciplinary features of the Special Issue, several topics were studied in the papers submitted to the issue.  
The noise control topic is studied by [PERSON] et al. [1] and [PERSON] et al. [2], regarding respectively noise barrier insertion loss and car silencers.  
Medical applications are presented in [3; 4; 5; 6]. Hearing issues are studied by [PERSON] et al., comparing normal-hearing subjects and cochlear implant users, and [PERSON] et al., regarding the effects of surgical instruments in ear surgery. High-intensity focused ultrasound (HIFU) non-invasive therapy is studied by [PERSON] et al., [PERSON] et al. and [PERSON] et al., concerning respectively the prediction of HIFU propagation in a dispersive medium, the influence of dynamic tissue properties on HIFU hyperthermia and acoustic field of focused ultrasound transducers.  
In addition to HIFU, ultrasound waves are presented in several and various applications [7; 8; 9; 10]. In particular, [PERSON] et al. proposes a method to estimate the soil depth based on elastic wave velocity. Some underwater applications are presented by [PERSON] et al. and [PERSON] et al., considering respectively underwater acoustic communication and channel modelling and estimation, and underwater acoustic sources estimation. [PERSON] et al. [11] presents an application of hydro-elastic analysis of a submerged floating tunnel under extreme wave and seismic excitations.  
The topic of the acoustic ultrasound emissions study for monitoring of fatigue crack growth in mooring chains [12] and for rail defect detection [13] is faced respectively by [PERSON] et al. and [PERSON] et al., with very interesting results. [PERSON] et al. applies the acoustic emissions technique to epoxy resin electrical freeing study [14]. Also, [PERSON] et al. [15] proposes the evaluation of cracks in metallic material.  
Vibration and vibroacoustic studies are presented in [16; 17; 18; 19], by [PERSON] et al., [PERSON] et al. and [PERSON] et al., with applications to parabolic tapered annular circular plate ([PERSON] et al. 2018 and 2019) and sensorized prodder for landmine detection ([PERSON] et al.). Also, [PERSON] et al. studies the vibrations, but referred to piano keys and their influence on piano players' perception and performance [20].  
[PERSON] et al. [21] and [PERSON] et al. [22] present their results on transducers, respectively on a 3D model of electromagnetic acoustic transducers and balanced armature receiver optimal design.  
Target speech with nonlinear soft masking is presented by [PERSON] et al. [23] while [PERSON] et al. [24] reports a study about spatial information on voice generation.  
Propagation in a fluid-filled polyethylene pipeline is studied from an experimental point of view by [PERSON] et al. in [25].  
[PERSON] et al. [26] presents a study on the acoustics of the Syracuse open-air theatre, with experiments and simulations. A room acoustic experiment is proposed by [PERSON] et al. in [27] to investigate fingerprinting acoustic localization indoors.  
Noncontact audio recording and a multi-frame Principal Component Analysis (PCA) based stereo audio coding method are proposed respectively by [PERSON] et al. [28] and [PERSON] et al. [29].  
[PERSON] et al. [30] proposes a material for acoustic lenses compatible with magnetic resonance imaging.  
An acoustic detection method for localization is proposed by [PERSON] et al. in [31].  
[PERSON] [32] proposes a survey of the boundary element method in acoustics.  
Sparse impulse response estimation is treated in [33] by [PERSON] et al.