per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 1 9 article A. Mohammadian Dehziri mohammadian@mut-es.ac.ir 1 M. Maesoumi mmaesoumi@yahoo.com 2 Islamic Azad Univ., Shiraz Branch Islamic Azad Univ., Jahrom Branch In this paper investigation of acoustic-communication synchronization method for shallow-water data communication is presented and a method is proposed and is evaluated for long-range applications. The proposed method is based on A) an empirical methodology and B) borrowing the concept of the television synchronization method. In proposed method, a mechanism is adopted in packet structure by which the receiver synchronizer extracts the beginnings of the transmitted packet through the communication task. Because of the acoustic nature of the channel (underwater communication channel) and non-applicability of EM propagation in water, the terrestrial synchronization methods (such as TV synchronization method) are not suitable for underwater applications, so the proposed method is effective for shallow-water acoustic communication. Main contribution of the paper is the proposal of a novel synchronization protocol for medium to long-range shallow-water (acoustic) data-communication systems. In order to evaluate the proposed method and protocol, a FSK acoustic modem (medium-range class) was developed which the results show the effectiveness of the proposed method and protocol for medium up to long-range acoustic data communication. http://joasi.ir/article-1-26-en.pdf Communication Acoustic Underwater Shallow water Synchronization per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 10 25 article M.R. Rahimi mr_rahimi@shirazu.ac.ir 1 H. Sadeghi h.sadeghi.2015@ieee.org 2 A. Ghasemi 3 M. Shamsi 4 Faculty of Electronic and Computer Engineering, Shiraz University Department of Electrical and Computer Engineering, Tarbiat Modares University Department of Electrical and Computer Engineering, Kashan University Department of Biomedical Engineering, Faculty of Electrical Engineering, Iran University of Science and Technology This paper proposes a hybrid acoustical source-location finding method using the hyperbolic localization and cross-bearing intersection techniques. The method employs the time delays estimations (TDE) observed from multiple sensors in order to find the location of the acoustic source in the near or far-filed. Since according to the existing literature, the conventional hyperbolic localization method does not provide enough accuracy for position-finding (PF), we propose that this method only be employed for obtaining TDEs. Then, using TDEs, the source position will be determined using the cross-bearing method. The simulation results show the significant improvement in source-position estimations as compared to traditional hyperbolic PF method. Furthermore, we also propose a method for accelerating the runtime of the optimization algorithm in the hybrid PF method.  http://joasi.ir/article-1-57-en.pdf Localization Acoustical sources Direction of arrival Cross bearing Time delay estimations per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 26 36 article A. Nouri ali_nori@iust.ac.ir 1 M. Badali eng.mina.badali@gmail.com 2 Aerospace Department, Shahid Sattry Air University Islamic Azad University Garmsar Branch In the present study, transmission loss of a bi-layered Functionally Gradient Materials (FGM) cylindrical shell with infinite length, subjected to a harmonic plane wave with a constant axial airflow in the external fluid medium, is studied analytically. In order to calculate the transmission loss at the whole range of frequency the vibration equations of bi-layered FGM shells in three directions are coupled with Helmholtz acoustic equations of the internal and external fluid of the shell and solved simultaneously. Modal interaction approach is used to solve the equations in this approach all variables such as displacement of shells and acoustic pressure are expressed as infinite series, therefore in this study, convergence of the series also is considered. To check the validity, accuracy and efficiency of the present model, results obtained are compared with the results of other researchers. The effect of power law exponent on shell stiffness, volume fraction, elasticity modulus and density of bi-layered FGM shell is shown. Also the effects of the volume fraction and different materials of layers are investigated on transmission loss. Also, the sound transmission loss of bi-layer FGM shell is compared with one layer FGM and aluminum shells. The result shows in the whole range of frequency the transmission loss of FGM bi-layered shell is better than the other shells. http://joasi.ir/article-1-67-en.pdf Functionally graded materials bi-Layered cylindrical shells Sound transmission Acoustic pressure per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 37 45 article A. Akhavan Bitaghsir amirakhavan.b@gmail.com 1 A. Mahloojifar Mahlooji@modares.ac.ir 2 Medical Engineering Department, Faculty of Electrical and Computer Engineering, Tarbiat Modares University Medical Engineering Department, Faculty of Electrical and Computer Engineering, Tarbiat Modares University Coded excitation is one of the important methods to increase medical ultrasound imaging depth. Commonly match filters are used to retain the axial resolution of ultrasound images in this type of excitation. Frequency dependent attenuation in the propagation medium of ultrasound wave, degrades the pulse compression performance of matched filter in coded excitation ultrasound imaging. In this paper fractional Fourier transform is proposed as an alternative method for pulse compression in high attenuating medium. Additionally a chirp signal detector is proposed in fractional domain in order to detect the echo signals and compare the performance of matched filter and fractional Fourier transform quantitatively. The comparison of this two methods shows that signal to noise ratio of fractional Fourier transform output is more than that of matched filter in deep parts in which ultrasound wave faces high level of attenuation. Simulation results show that pulse compression with fractional Fourier transform is less sensitive to frequency dependent attenuation. In other words, in the presence of frequency dependent attenuation, the detection probability of echo signal in fractional domain is more than that of match filter. The amount of improvement in the proposed method depends on the imaging depth and the value of attenuation in the medium. In other words, the more the imaging depth the more improvement is achieved by the propose method. Finally using Wigner-Ville time-frequency representation we consider the reason of better performance of fractional Fourier transform over matched filter. http://joasi.ir/article-1-54-en.pdf Fractional Fourier transform Matched filter Pulse compression Coded excitation Medical ultrasound imaging per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 46 55 article M.E. Ravari 1 M. Mokhtari-Dizaji mokhtarm@modares.ac.ir 2 S.H. Momeni-Masuleh 3 S. Motiee 4 Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University Department of Mathematics, Faculty of Basic Sciences, Shahed University Department of Mathematics, Faculty of Basic Sciences, Shahed University One of cancer;#39s therapeutic methods is applying ultrasound induced hyperthermia independently or in combination with other therapeutic methods like radiotherapy and chemotherapy. Because of improper distribution of sonication in tissue under treatment and not achieving to a suitable treatment planning during sonication, tissue temperature do not regulate correctly. So in this study to achieve ultrasonic treatment planning protocol, Rayleigh integral has been used for modeling propagation of sound. In this study, Rayleigh integral for two 1 MHz ultrasonic transducers have been solved in cylindrical coordinates for the purpose of estimating effects of 0.8 and 5.0 cm2 effective radiation area and different intensities. Ultrasonic pressure distribution in axial, radial and angular directions were extracted. For validation of modeling results, acoustic pressure value in aqueous medium and at specific distances from transducer face has been measured using piston hydrophone. The results show that there are good agreement between modeling results and experimental measurements with 0.82 correlation of coefficient (p-value<0.05). The mean relative error is 7.34 percent for 5.0 cm2 effective radiation area with 1.5 to 14.2 percent interval. It is concluded that this model is capable of modeling sound propagation in tissue and performing first step in hyperthermia treatment planning with acceptable accuracy. http://joasi.ir/article-1-58-en.pdf Ultrasound waves Modeling Rayleigh Integral Effective radiation area Hyperthermia per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 56 65 article A. Akhavan Bitaghsir 1 M. H. moradi 2 Processing of infant cry sound provides useful information about his/her condition. This information can be used to establish a diagnostic method to determine the infant;#39s needs. This paper addresses the analysis of newborn babies cry sound in order to discriminate crying associated with hunger from that originating from pain. Sparse representation models are one of the state of the art processing tools in pattern recognition and machine learning. In this work a novel framework is proposed in order to deal with sparsity-based approach in a classification task. The dictionary atoms of the sparse model are designed using Mel Frequency Cepstrum Coefficient in kernel space. Performance assessment of kernel sparse representation model shows the discriminative power of this model in classifying different types of infant cry sound. In order to compare, the results of conventional sparse representation model and some other well-known classifiers (Hidden Markov Model and Support Vector Machine) are also presented. The results show that the proposed model has better performance in comparison with the other presented classifiers. Using 6-fold cross validation the kernel sparse model can distinguish two types of infant cry with more than 93% accuracy. The pain and hunger databases are recorded from 51 (19 male and 32 female) 2-3 day old healthy infants. http://joasi.ir/article-1-61-en.pdf Sparse Representation Model Sparse Representation Classifier Kernel-based model Mel Frequency Cepstrum Coefficient Infant cry sound per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 66 72 article M. B. Abdollahi abdollahimb@gmail.com 1 A. Khavanin khavanin@modares.ac.ir 2 S. Vosoughi sh_vosoughi@yahoo.com 3 S. Amanpour saeidamanpour@yahoo.com 4 M. Kaidani kaydanym@yahoo.com 5 S. Noorloei s.noori1366@yahoo.com 6 MD1-MAPNA tarbiat modares uni shahid beheshti uni tehran uni Noise as one of the most important physical agents in workplace, which is known to have adverse effects on living organisms and biological systems, has been studied repeatedly. Noise negative effects on count, motility and viability of sperm can be considered as important  factor in reproduction system. In this study, 16 male mice were used in two groups: case and control. Combined noise with 8000-500 Hz bandwidth and with sound pressure level 100±2 dBA for 10 days in two consecutive weeks was created using the software cool edit tools. Then, 35 days after the end of exposure animals were killed and their testes were separated for sperm analysis. The results of this study showed that in the case group progressive sperm (31.4 ± 1.9), immotile sperm (35.9 ± 3.4) and sperm viability (64.8±4.3) are significantly decreased compared to controls group (P0.05). Noise exposure may have negative effects on sperm quality. http://joasi.ir/article-1-56-en.pdf Noise Sperm parameters Mice per Acoustical Society of Iran Journal of Acoustical Society of Iran 2345-5748 2345-5748 2015-09 3 1 73 79 article A. Lashkarbolouk ahmad.lashkar@yahoo.com 1 G.R. Etaati r_etaati@aut.ac.ir 2 M. Eftekhariyazdi eftekhariyazdi@yahoo.com 3 Department of Engineering, Islamic Azad University Central Tehran Branch Department of Energy Engineering and Physics, Amirkabir University of Technology Department of Engineering, Islamic Azad University Central Tehran Branch Thermoacoustics is a science dealing with conversion of thermal energy into sound energy and vice versa. Thermoacoustic systems use thermoacoustics rules for heat transfer by sound. These devices include a loudspeaker, a standing wave tube with a length of a fraction of a wavelength and a stack which its temperature gradient is the cause of heat transfer. In this study, design and construction of a low power thermoacoustic system for air conditioning applications, were considered. This paper consist of two parts: design of a thermoacoustic system based on numerical analyses, and its construction plus its performance analysis. Numerical analyses reveals that the length and position of the stack in the resonator, the working frequency and the input acoustic power, have major contributions to the total performance of the system. In this system, helium at the standard pressure and temperature was used as working fluid. The acoustic driver was a 25 watts loudspeaker that works in 378Hz. Based on numerical analyses and a 20 °C temperature gradient quota, the length of the stack and the position of its center were found to be 38 mm and 85 mm, respectively. Our experimental results indicated a 14 C temperature gradient across the stack. http://joasi.ir/article-1-22-en.pdf Thermoacoustic Stack Resonator Working fluid Temperature gradient