The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Wan Kyun Chung - One of the best experts on this subject based on the ideXlab platform.
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3D underwater localization scheme using em Wave Attenuation with a depth sensor
Proceedings - IEEE International Conference on Robotics and Automation, 2016Co-Authors: Daegil Park, KYUNG MIN KWAK, Jinhyun Kim, Wan Kyun ChungAbstract:Previously, we proposed a scheme that determines the position of a remotely operated underwater vehicle (ROV) from the signal strengths of commercial radio-frequency sensors and antennas. This scheme provides accurate position information in a structured environment but is limited to two-dimensional (2D) environments because the radiation power of the antenna depends on the elevation angle between the sending and receiving antennas. To overcome this problem, we propose a 3D localization scheme that considers the electromagnetic (EM) Wave Attenuation over the range of reliable elevation angles. In order to determine the reliable elevation scope, we analyzed the radiation patterns of dipole antennas. The feasibility of our approach is demonstrated in distance estimation and 3D localization experiments by varying the distance and elevation angle. Encouraged by these results, we constructed an underwater wireless sensor network in the experimental basin, and performed ROV position tracking with the depth sensor. The scheme achieved reliable localization accuracy at a fast sampling rate, demonstrating the feasibility of exploiting EM Wave Attenuation in localization.
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Development of Underwater Short-Range Sensor Using Electromagnetic Wave Attenuation
IEEE Journal of Oceanic Engineering, 2016Co-Authors: Daegil Park, KYUNG MIN KWAK, Wan Kyun ChungAbstract:In this paper, we discuss a novel underwater short-range sensor using electromagnetic (EM) Wave Attenuation. We use the revised Friis-Shelkunoff formula to calculate the EM Wave Attenuation underwater as a function of distance. This requires knowledge of the antenna gain underwater, which is very different from the gain in air, and also the Attenuation constant which depends on the water conductivity. We calibrated the gain and Attenuation in a ranging experiment and also in a 2-D localization experiment. Both methods agreed, confirming that in situ calibration of a 2-D localization experiment is feasible. The localization results show good accuracy, validating the sensor model and showing that multipath effects can be made negligible in such an experiment.
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Preliminary results of 3D underwater localization using electromagnetic Wave Attenuation
2016 13th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI), 2016Co-Authors: KYUNG MIN KWAK, Daegil Park, Wan Kyun ChungAbstract:In this paper, we discuss a novel underwater localization method using 3D Electromagnetic (EM) Wave Attenuation pattern. To calculate the EM Wave Attenuation in underwater, according to distance, we use the Friis-Shelkunoff (FRIIS) formula, which mainly depends on antenna properties and medium variables. The research on these variables was executed in previous works [3, 4]. In this work, 3D underwater localization method is proposed using the 3D Attenuation model and depth data from the additional pressure sensor, which is realized with the several anchor nodes located in fixed positions and mobile node for receiving EM Waves with an attached pressure sensor. We measured mobile node Attenuation data in the underwater with position change in the x-z vertical plane. And it was compared with the theoretical 3D spatial Attenuation model. The preliminary results about 3D underwater localization show good agreement with theoretical estimation.
Chao-cheng Ku - One of the best experts on this subject based on the ideXlab platform.
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MicroWave and millimeter-Wave Attenuation in sand and dust storms
2012 19th International Conference on Microwaves Radar & Wireless Communications, 2012Co-Authors: Hsing-yi Chen, Chao-cheng KuAbstract:The finite-difference time-domain (FDTD) method and the turning bands method are used to calculate the Wave Attenuation in sand and dust storms at microWave and millimeter-Wave. The proposed formula shows that Wave Attenuation in sand and dust storms depends on the visibility, frequency, sand and dust particle radius, and on complex relative permittivity. Obtained results of the Wave Attenuation are also compared with those obtained by four other methods: the effective material property technique, the Rayleigh scattering approximation, the measured probability density function and Mie scattering theory, and the volumetric integration of Mie scattering results by individual particles. It is found that our formula produces a mean value of Wave Attenuation among these five formulas.
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Calculation of Wave Attenuation in Sand and Dust Storms by the FDTD and Turning Bands Methods at 10–100 GHz
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Hsing-yi Chen, Chao-cheng KuAbstract:The finite-difference time-domain method and the turning bands method are used to calculate the Wave Attenuation in sand and dust storms at the frequencies of 10-100 GHz. The digitized models, with a random process using the turning bands method, are simulated for sand and dust particles. The proposed formula shows that Wave Attenuation in sand and dust storms depends on the visibility, frequency, sand and dust particle radius, and on complex relative permittivity. Obtained results of the Wave Attenuation are also compared with those obtained by four other methods: the effective material property technique, the Rayleigh scattering approximation, the measured probability density function and Mie scattering theory, and the volumetric integration of Mie scattering results by individual particles. It is found that our formula produces a mean value of Wave Attenuation among these five formulas. It is confirmed that the Wave Attenuation is negligible except for frequencies above 30 GHz and for very severe storms with visibility less than 0.02 km. It is also found that the particle size distribution function and equivalent particle radius are two major factors which will affect the Wave Attenuation in sand and dust storms.
Weiho Chung - One of the best experts on this subject based on the ideXlab platform.
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calculation of Wave Attenuation in sand and dust storms by the fdtd and turning bands methods at 10 100 ghz
IEEE Transactions on Communications, 2012Co-Authors: Ronald Y Chang, Weiho ChungAbstract:The finite-difference time-domain method and the turning bands method are used to calculate the Wave Attenuation in sand and dust storms at the frequencies of 10-100 GHz. The digitized models, with a random process using the turning bands method, are simulated for sand and dust particles. The proposed formula shows that Wave Attenuation in sand and dust storms depends on the visibility, frequency, sand and dust particle radius, and on complex relative permittivity. Obtained results of the Wave Attenuation are also compared with those obtained by four other methods: the effective material property technique, the Rayleigh scattering approximation, the measured probability density function and Mie scattering theory, and the volumetric integration of Mie scattering results by individual particles. It is found that our formula produces a mean value of Wave Attenuation among these five formulas. It is confirmed that the Wave Attenuation is negligible except for frequencies above 30 GHz and for very severe storms with visibility less than 0.02 km. It is also found that the particle size distribution function and equivalent particle radius are two major factors which will affect the Wave Attenuation in sand and dust storms.
Daegil Park - One of the best experts on this subject based on the ideXlab platform.
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3D underwater localization scheme using em Wave Attenuation with a depth sensor
Proceedings - IEEE International Conference on Robotics and Automation, 2016Co-Authors: Daegil Park, KYUNG MIN KWAK, Jinhyun Kim, Wan Kyun ChungAbstract:Previously, we proposed a scheme that determines the position of a remotely operated underwater vehicle (ROV) from the signal strengths of commercial radio-frequency sensors and antennas. This scheme provides accurate position information in a structured environment but is limited to two-dimensional (2D) environments because the radiation power of the antenna depends on the elevation angle between the sending and receiving antennas. To overcome this problem, we propose a 3D localization scheme that considers the electromagnetic (EM) Wave Attenuation over the range of reliable elevation angles. In order to determine the reliable elevation scope, we analyzed the radiation patterns of dipole antennas. The feasibility of our approach is demonstrated in distance estimation and 3D localization experiments by varying the distance and elevation angle. Encouraged by these results, we constructed an underwater wireless sensor network in the experimental basin, and performed ROV position tracking with the depth sensor. The scheme achieved reliable localization accuracy at a fast sampling rate, demonstrating the feasibility of exploiting EM Wave Attenuation in localization.
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Development of Underwater Short-Range Sensor Using Electromagnetic Wave Attenuation
IEEE Journal of Oceanic Engineering, 2016Co-Authors: Daegil Park, KYUNG MIN KWAK, Wan Kyun ChungAbstract:In this paper, we discuss a novel underwater short-range sensor using electromagnetic (EM) Wave Attenuation. We use the revised Friis-Shelkunoff formula to calculate the EM Wave Attenuation underwater as a function of distance. This requires knowledge of the antenna gain underwater, which is very different from the gain in air, and also the Attenuation constant which depends on the water conductivity. We calibrated the gain and Attenuation in a ranging experiment and also in a 2-D localization experiment. Both methods agreed, confirming that in situ calibration of a 2-D localization experiment is feasible. The localization results show good accuracy, validating the sensor model and showing that multipath effects can be made negligible in such an experiment.
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Preliminary results of 3D underwater localization using electromagnetic Wave Attenuation
2016 13th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI), 2016Co-Authors: KYUNG MIN KWAK, Daegil Park, Wan Kyun ChungAbstract:In this paper, we discuss a novel underwater localization method using 3D Electromagnetic (EM) Wave Attenuation pattern. To calculate the EM Wave Attenuation in underwater, according to distance, we use the Friis-Shelkunoff (FRIIS) formula, which mainly depends on antenna properties and medium variables. The research on these variables was executed in previous works [3, 4]. In this work, 3D underwater localization method is proposed using the 3D Attenuation model and depth data from the additional pressure sensor, which is realized with the several anchor nodes located in fixed positions and mobile node for receiving EM Waves with an attached pressure sensor. We measured mobile node Attenuation data in the underwater with position change in the x-z vertical plane. And it was compared with the theoretical 3D spatial Attenuation model. The preliminary results about 3D underwater localization show good agreement with theoretical estimation.
Rusty A Feagin - One of the best experts on this subject based on the ideXlab platform.
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short communication engineering properties of wetland plants with application to Wave Attenuation
Coastal Engineering, 2011Co-Authors: Rusty A Feagin, Jennifer L Irish, Iris Moller, Amy M Williams, Ricardo J Colonrivera, Mir Emad MousaviAbstract:Abstract This technical note presents empirically-derived values for biophysical attributes of several commonly occurring wetland plant species, including plant stem diameter and tapering, plant clump and stem spacing statistics, biomass, Young's modulus of elasticity, and bending strength. These parameters can be used to more realistically configure plant canopies in numerical and laboratory studies to further our understanding of Wave Attenuation by wetlands.
