فهرست مطالب aliasghar abniki

Here, it is investigated the results of implementation of interferometric optical fiber acoustic sensor based on fiber Bragg grating (FBG). It is investigated the importance of different types of interferometers configurations as Michelson or Mach-Zehnder interferometers on the signal to noise ratio. It is also considered the role of polymer coating on the increasing of signal to noise ratio. The results show, the Michelson interferometer setup using polymer packaging causes increasing signal to noise ratio. This latter configuration is used in a field setup in shallow water for acoustic signal detection in range of 0.5-5 kHz. The goal of this paper is extracting acoustical signal using optical signal via optical sensors and demodulation methods.Here, it is investigated the results of implementation of interferometric optical fiber acoustic sensor based on fiber Bragg grating (FBG). It is investigated the importance of different types of interferometers configurations as Michelson or Mach-Zehnder interferometers on the signal to noise ratio. It is also considered the role of polymer coating on the increasing of signal to noise ratio. The results show, the Michelson interferometer setup using polymer packaging causes increasing signal to noise ratio. This latter configuration is used in a field setup in shallow water for acoustic signal detection in range of 0.5-5 kHz. The goal of this paper is extracting acoustical signal using optical signal via optical sensors and demodulation methods.

Direction of Arrival (DOA) estimation of sound sources using phased array-based methods has a lot of importance in various fields, including sonar, robot vision and mechanical defect detection. Adaptive beamforming methods, such as the MVDR (Minimum Variance Distortionless Response) algorithm, have high resolution compared to non-adaptive methods; but this advantage is achieved in return for the computational complexity of these algorithms. This makes it hard to use these algorithms in applications that require real-time sound source DOA estimation. On the other hand, an important feature of the adaptive beamforming methods including MVDR is the high potential of these algorithms for parallelization. The purpose of this paper is the parallel implementation of the MVDR algorithm by employing GPU instead of CPU to increase the execution speed and achieve real-time mode. To achieve this purpose, the CUDA programming model has been used to implement the algorithm on the GPU. In order to investigate the performance of parallel implementation of the MVDR algorithm, two different GPUs, as well as CPUs, have been used. The performance validity of various implementations in this paper was confirmed by real sonar data as well as simulation data. The results show that using an array of 64 sensors, it is possible to estimate the DOA of underwater sound sources in real-time and with high resolution using the MVDR algorithm.

The aim of this study was determination of the Relationships of personality treaties and change management with mediator’s role of strategic thinking on sport facility managers in Tehran. Statistical population was whole of sport facility managers. Based on Cochran’s formula sample comprise 384 sport facility managers. In order to collection data Short - scale questionnaire BIG-five dimensions of personality, Change management questionnaire, and strategic thinking questionnaire were use. Descriptive statistics, multiple regression and SEM for data analysis were use. Data analysis revealed that there are a significant relationship between personality treaties with strategic thinking and change management in s sport facility managers (p < 0.05). Also there is a significant relationship between strategic thinking and change management (p < 0.05). Results of SEM showed that personality treaties has direct effect on strategic thinking (pc=0.50) and change management (pc=0.62). Also strategic think has direct effect on change management (pc=0.51). According to result, can be concluded that personality treaties of sport managers with strategic thinking can cause favorable changes in sport Facilities. Therefore it is recommended that sport managers focus on systems thinking and Agreeableness as the most important factors affecting the change management.

In this paper, we present experimental results of one optical fiber acoustic sensor in shallow water. Output trend of sensor is investigated primarily comparing with the change of acoustic amplitude of transmitter and then the frequency response of sensor is determined. The results show that, the optical fiber sensor has linear trend comparing with a standard hydrophone and its frequency response is similar to that of hydrophone. The results show that the optical fiber sensor output has equal trend comparing to a standard hydrophone. The results also show that, the frequency response trend of optical fiber sensor at 0.7- 5 kHz range is similar to that of a standard hydrophone.

In this paper, an underwater targets classification system is presented using the noise released from them. This system is proposed for shallow water environments such as Persian Gulf. Acoustic noise is non-Gaussian and due to the near-surface and properties of the environment acoustic noise is nonlinear and nonstationary. This fact affects the quality of the classification system. To classify acoustic noise, a target identification system is developed using a feature extraction section based on Hilbert Huang's Transform (HHT) and Support Vector Machine (SVM). Then the performance of the proposed method is illustrated using simulation results. Simulations take on two groups of signals. The first group of noise was related to three different type of vessels, and the second group of noise was related to a number of heavy and a number of light vessels, which were used in the Persian Gulf. Classification results show that the proposed method has a better performance than the wavelet transform method.