The Experts below are selected from a list of 108093 Experts worldwide ranked by ideXlab platform
Fubin Chen - One of the best experts on this subject based on the ideXlab platform.
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force Frequency characteristics of multi electrode quartz crystal resonator cluster
Sensors and Actuators A-physical, 2018Co-Authors: Fubin Chen, Wenjie TianAbstract:Abstract The quartz resonator has a significant force-sensitive effect under the action of force. It is most commonly used in the field of modern digital measurement and control. To reduce temperature and other interference factors as well as improve force-sensitivity, a stress distribution is derived and calculated in the quartz wafer by radial force under the elastic mechanics method. A multi-electrode force-sensitive resonator cluster is designed based on the stress distribution results. The experimental results show that the sensitivity of the quartz resonator cluster is better than the traditional single electrode resonator and that the overall force-Frequency Coefficient of the force-Frequency reaches 10,167 Hz/N. The quartz resonator cluster is a viable sensitive element for high-precision digital inertial sensors and related detection systems.
Robert M. Hierons - One of the best experts on this subject based on the ideXlab platform.
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AINA - JPEG Steganography: A Performance Evaluation of Quantization Tables
2009 International Conference on Advanced Information Networking and Applications, 2009Co-Authors: Adel Almohammad, Gheorghita Ghinea, Robert M. HieronsAbstract:The two most important aspects of any image based steganographic system are the imperceptibility and the capacity of the stego image. This paper evaluates the performance and efficiency of using optimized quantization tables instead of default JPEG tables within JPEG steganography. We found that using optimized tables significantly improves the quality of stego-images. Moreover, we used this optimization strategy to generate a 16x16 quantization table to be used instead of that suggested. The quality of stego-images was greatly improved when these optimized tables were used. This led us to suggest a new hybrid steganographic method in order to increase the embedding capacity. This new method is based on both and Jpeg-Jsteg methods. In this method, for each 16x16 quantized DCT block, the least two significant bits (2-LSBs) of each middle Frequency Coefficient are modified to embed two secret bits. Additionally, the Jpeg-Jsteg embedding technique is used for the low Frequency DCT Coefficients without modifying the DC Coefficient. Our experimental results show that the proposed approach can provide a higher information-hiding capacity than the other methods tested. Furthermore, the quality of the produced stego-images is better than that of other methods which use the default tables.
Wenjie Tian - One of the best experts on this subject based on the ideXlab platform.
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force Frequency characteristics of multi electrode quartz crystal resonator cluster
Sensors and Actuators A-physical, 2018Co-Authors: Fubin Chen, Wenjie TianAbstract:Abstract The quartz resonator has a significant force-sensitive effect under the action of force. It is most commonly used in the field of modern digital measurement and control. To reduce temperature and other interference factors as well as improve force-sensitivity, a stress distribution is derived and calculated in the quartz wafer by radial force under the elastic mechanics method. A multi-electrode force-sensitive resonator cluster is designed based on the stress distribution results. The experimental results show that the sensitivity of the quartz resonator cluster is better than the traditional single electrode resonator and that the overall force-Frequency Coefficient of the force-Frequency reaches 10,167 Hz/N. The quartz resonator cluster is a viable sensitive element for high-precision digital inertial sensors and related detection systems.
Jack Y.k. Lou - One of the best experts on this subject based on the ideXlab platform.
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Alternating Frequency/Coefficient (AFC) technique in the harmonic balance method
International Journal of Non-linear Mechanics, 1996Co-Authors: Geng Xie, Jack Y.k. LouAbstract:A solution procedure for a system of non-linear equations containing a convolution term is developed by using the harmonic balance method in conjunction with a new alternating Frequency/Coefficient (AFC) technique. Numerical results show that, unlike the conventional harmonic balance method, the new technique is very effective in searching for solutions for multi-valued non-linear problems, especially in the vicinity of a jump phenomenon.
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Alternating Frequency/Coefficient (AFC) technique in the trigonometric collocation method
International Journal of Non-Linear Mechanics, 1996Co-Authors: Geng Xie, Jack Y.k. LouAbstract:The trigonometric collocation method is extended to non-linear systems containing convolution terms. A complete solution procedure is developed by reformulating the Alternating Frequency/Coefficient technique in conjunction with the trigonometric collocation method. Numerical results show that the procedure is computationally more efficient for large non-linear systems as compared to the harmonic balance method. In addition, compared with the conventional trigonometric collocation method, the new procedure is more effective in dealing with complex non-linear phenomena, especially in the vicinity of a bifurcation point.
Adel Almohammad - One of the best experts on this subject based on the ideXlab platform.
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AINA - JPEG Steganography: A Performance Evaluation of Quantization Tables
2009 International Conference on Advanced Information Networking and Applications, 2009Co-Authors: Adel Almohammad, Gheorghita Ghinea, Robert M. HieronsAbstract:The two most important aspects of any image based steganographic system are the imperceptibility and the capacity of the stego image. This paper evaluates the performance and efficiency of using optimized quantization tables instead of default JPEG tables within JPEG steganography. We found that using optimized tables significantly improves the quality of stego-images. Moreover, we used this optimization strategy to generate a 16x16 quantization table to be used instead of that suggested. The quality of stego-images was greatly improved when these optimized tables were used. This led us to suggest a new hybrid steganographic method in order to increase the embedding capacity. This new method is based on both and Jpeg-Jsteg methods. In this method, for each 16x16 quantized DCT block, the least two significant bits (2-LSBs) of each middle Frequency Coefficient are modified to embed two secret bits. Additionally, the Jpeg-Jsteg embedding technique is used for the low Frequency DCT Coefficients without modifying the DC Coefficient. Our experimental results show that the proposed approach can provide a higher information-hiding capacity than the other methods tested. Furthermore, the quality of the produced stego-images is better than that of other methods which use the default tables.