Comparative Study of Acoustic Parameter Reconstruction by using Optimal Control Method and Inverse Scattering Approach

Reconstruction of acoustic parameter such as acoustic velocity considers as part of inverse problems for mathematical physics and reasonable reconstruction of this parameter will assist solving interrelated problem such as inversion and imaging which are popular in the field of seismic imaging. In this work, we studied and conducted a comparative study between two methods; the optimal control method and inverse scattering approach. In optimal control method we are using conjugate gradient method for reconstructing the desired acoustic parameter while for inverse scattering approach, we are introducing the application of Marchenko integral equation. Furthermore, the numerical results for both approaches are presented for one dimensional problem along with the analysis from this comparative study.

Contact calls in woodpeckers are individually distinctive, show significant sex differences and enable mate recognition

Vocal communication of woodpeckers has been relatively little studied so far, mostly because majority of species use drumming to communicate. Our recent study on the Middle Spotted Woodpecker revealed that a call which is specific for floaters is individually distinctive and functions as a vocal signature of unpaired individuals. The aim of the current study is to investigate whether a contact call of paired territory owners of the same species enables discrimination of individuals and their sex. Acoustic analyses revealed that the call is individually distinctive and experimental approach confirmed that woodpeckers are able to distinguish between a contact call of their partner and a stranger. We also found that the contact call shows significant sex differences. Interestingly, the acoustic parameter enabling sex identification is different than the parameters coding individual variability of the call. The design of a call so that its first part would code the identity of an individual and the second part would code its sex presents an effective and fine-tuned communication system. The results of our study also suggest that the contact call of paired Middle Spotted Woodpeckers may be useful for conservation biologists as a tool supporting other census methods.

Classification of Parkinson Disease Based on Analysis and Synthesis of Voice Signal

The most important application of voice profiling is pathological voice detection. Parkinson's disease is a chronic neurological degenerative disease affecting the central nervous system responsible for essentially progressive evolution movement disorders. 70% to 90% of Parkinson’s disease (PD) patients show an affected voice. This paper proposes a methodology for PD based on acoustic, glottal, physical, and electrical parameters. The results show that the acoustic parameter is more important in the case of Parkinson’s disease as compared to glottal and physical parameters. The authors achieved 97.2% accuracy to differentiate Parkinson and healthy voice using jitter to pitch ratio proposed algorithm. The Authors also proposed an algorithm of poles calculation of the vocal tract to find formants of the vocal tract. Further, formants are used for finding the transfer function of vocal tract filter. In the end, the authors suggested parameters of the electrical vocal tract model are also changed in the case of PD voices.

An Investigational Approach for Vowels of the Salar Language Based on a Database of Speech Acoustic Parameters

According to relevant specifications, this article divides, marks, and extracts the acquired speech signals of the Salar language, and establishes the speech acoustic parameter database of the Salar language. Then, the vowels of the Salar language are analyzed and studied by using the parameter database. The vowel bitmap (average value at the beginning of words), the vowel bitmap (average value at the abdomen of words), the vowel bitmap (average value at the ending of words), and the vowel bitmap (average value) are obtained. Through the vowel bitmaps, we can observe the vowel in different positions of the word, the overall appearance of an obtuse triangle. The high vowel [i], [o], and low vowel [a] occupy three vertices, respectively. Among the three lines, [i] to [o] are the longest, [i] to [a] are the second longest, and [a] to [o] are the shortest. The lines between [a] to [o] and [a] and [i] are asymmetric. Combining with the vowel bitmap, the vowels were discretized, and the second formant (F2) frequency parameter was used as the coordinate of the X axis, and the first formant (F1) frequency was used as the coordinate of the Y axis to draw the region where the vowel was located, and then the vowel pattern was formed. These studies provide basic data and parameters for the future development of modern phonetics such as the database of Sarah language speech, speech recognition, and speech synthesis. It also provides the basic parameters of speech acoustics for the rare minority acoustic research work of the national language project.

Green Shipping—Multifunctional Marine Scrubbers for Emission Control: Silencing Effect

Scrubber systems abate the sulphur oxide emissions of engines when cheap fuel oils that are high in sulphur content are employed as combustibles. However, the ships with these voluminous devices installed on board is space demanding. This work analyses the feasibility of incorporating the acoustic abatement of the exhaust gas noise functionality into the scrubber design to provide a combined scrubber–silencer system. For this purpose, a finite element analysis is performed on a simple expansion chamber, which is assessed using both analytical and experimental data. The transmission loss is the acoustic parameter chosen in this work. The numerical model depicts a good correlation with the transmission loss measured on a model scale scrubber. Finally, scrubber geometry modifications alter the transmission loss, changing and/or enhancing its featuring. These abilities indicate the feasibility to confer to scrubber silencing effects.

Indirect determination of airflow resistance of textiles with reference samples

Airflow resistance is a non-acoustic parameter of great relevance in the acoustic characterization of porous materials. It is used in several sound absorbing material prediction models and it is also a control parameter for acoustic conditioning and insulation in different building solutions. The ISO 9053 standard defines several methods to obtain it, using both direct measurements and indirect techniques. However, both procedures may involve problems related to the placement of the textile samples in the tube or to the stability of the samples during testing. In this work, the use of reference materials to stabilize the measurement of thin materials is proposed. Airflow resistance results obtained for different materials in an impedance tube are presented. The tests have been carried out by following the Ingard & Dear method, as an indirect technique accepted by the standard. Several material compositions with a wide range of airflow resistance values have been analyzed with different reference materials.

Assessment of inter-IC sound microelectromechanical systems microphones for soundscape reporting

Acoustic parameters obtained from calibrated acoustic equipment are part of the minimum soundscape reporting requirements as stated in Annex A of ISO 12913-2. To dynamically monitor the acoustic environment of a large area, a large network of acoustic sensors could be deployed, albeit at significant cost. Micro-Electro-Mechanical Systems (MEMS) microphones offer compact, low-cost and high-performance alternatives to traditional analog microphones. In particular, the use of Inter-IC Sound (IS) communication allows MEMS microphones to be conveniently used in concert with I2S output interfaces for sound actuation. The performance of several IS MEMS Microphones was compared to that of an IEC 61094-4:1996 WS2F microphone in an anechoic chamber and a series of digital filters was designed to compensate for the differences in frequency response. The noise floor, compensated frequency response, acoustic parameter accuracy of IS MEMS were evaluated and recommendations regarding the suitability of the IS MEMS were provided.

The duration of word-final s in English: A comparison of regular-plural and pluralia-tantum nouns

The alveolar fricative occurs in word-final position in English in different grammatical functions. Nominal suffixes may indicate plurality (e.g. cars), genitive case (e.g. car’s) or plurality and genitive case in cumulation (e.g. cars’). Further, there are the third person singular verbal suffix (e.g. she fears) and the cliticized forms of the third person singular forms of have and be (e.g. she’s been lucky; she’s friendly). There is also non-affixal s (e.g. freeze (noun)). Against the standard view that all these types are homophonous, several empirical studies have shown that at least some of the fricatives listed can actually be differentiated in their duration. The present article expands this line of research and considers a further case, which has not been included in previous analyses: pluralia-tantum nouns (e.g. goggles). We report on a carefully controlled reading study in which native speakers of British English produced pluralia-tantum and comparable regular-plural nouns (e.g. toggles). The duration of the word-final fricative was measured, and it was found that the two do not systematically differ in this acoustic parameter. The new data are interpreted in comparison to relevant previous studies, and against the background of the similarities of pluralia-tantum and regular-plural nouns.