A new fractal image compression algorithm based on high frequency energy (HFE) partitioning andmatched domain block searching is presented to code synthetic aperture radar (SAR) imagery. In the hybridcoding algorithm,...A new fractal image compression algorithm based on high frequency energy (HFE) partitioning andmatched domain block searching is presented to code synthetic aperture radar (SAR) imagery. In the hybridcoding algorithm, the original SAR image is decomposed to low frequency components and high frequencycomponents by wavelet transform (WT). Then the coder uses HFE of block to partition and searchthe matched domain block for each range block to code the low frequency components. For the high frequencycomponents, a modified embedded zero-tree wavelet coding algorithm is applied. Experiment resultsshow that the proposed coder obtains about 0. 3dB gain when compared to the traditional fractal coderbased on the quadtree partition. Moreover, the subjective visual quality of the reconstructed SAR imageof the proposed coder outperforms that of the traditional fractal coders in the same compression ratio(CR).展开更多
The present paper addresses the subject of truss damage identification using measured frequency response functions (FRF). Damage identification matrix is formed using measured FRFs obtained from truss dynamic test. Th...The present paper addresses the subject of truss damage identification using measured frequency response functions (FRF). Damage identification matrix is formed using measured FRFs obtained from truss dynamic test. Then using principal component analysis (PCA),the variable space dimensions of damage identification matrix can be reduced,and original data characters of FRFs can be analyzed and extracted from lower dimension variable space. Thus truss damages can be identified using the multivariate control chart of first several order principal components which contain almost all of original data information. Without the need for modal parameters,the method avoids the errors of modal fitting. In order to validate the reliability of the method,a whole size truss was tested with six types of damage case concerning single or two element damages. The experimental result shows that the proposed method is straightforward and reliable for truss damage identification. Especially,the method has good applicability for the truss under noisy environment and non-linear cases.展开更多
Visual and pictorial materials are extensively used in teaching listening comprehension textbooks. Although the use of still image is currently implemented in some distinguished testing systems, video test is not a po...Visual and pictorial materials are extensively used in teaching listening comprehension textbooks. Although the use of still image is currently implemented in some distinguished testing systems, video test is not a popular modality due to the fact that this kind of test may result in test-takers＇ confusion during the test. In the present study, a sample of 80 Iranian EFL （English as a Foreign Language） students was selected to compare their performance on three different modalities of listening test： audio-only test, pictorial （listening with still image test）, and visual （video） listening test. The analysis of one-way repeated measure ANOVA （Analysis of Variance） was used to compare the students＇ scores. The results of Bonferroni Post Hoc Test confirm that there were significant differences in scores among audio-only, pictorial, and visual tests. The results of this study highlight the greater performance of students in pictorial listening test which is statistically significant.展开更多
基金Supported by the National Natural Science Foundation of China (No. 90304003)the President Fund of GUCAS (No. O85101HM03).
文摘A new fractal image compression algorithm based on high frequency energy (HFE) partitioning andmatched domain block searching is presented to code synthetic aperture radar (SAR) imagery. In the hybridcoding algorithm, the original SAR image is decomposed to low frequency components and high frequencycomponents by wavelet transform (WT). Then the coder uses HFE of block to partition and searchthe matched domain block for each range block to code the low frequency components. For the high frequencycomponents, a modified embedded zero-tree wavelet coding algorithm is applied. Experiment resultsshow that the proposed coder obtains about 0. 3dB gain when compared to the traditional fractal coderbased on the quadtree partition. Moreover, the subjective visual quality of the reconstructed SAR imageof the proposed coder outperforms that of the traditional fractal coders in the same compression ratio(CR).
基金the Foundation of Henan Province Key Technology R and D Program(Grant No.0423033700).
文摘The present paper addresses the subject of truss damage identification using measured frequency response functions (FRF). Damage identification matrix is formed using measured FRFs obtained from truss dynamic test. Then using principal component analysis (PCA),the variable space dimensions of damage identification matrix can be reduced,and original data characters of FRFs can be analyzed and extracted from lower dimension variable space. Thus truss damages can be identified using the multivariate control chart of first several order principal components which contain almost all of original data information. Without the need for modal parameters,the method avoids the errors of modal fitting. In order to validate the reliability of the method,a whole size truss was tested with six types of damage case concerning single or two element damages. The experimental result shows that the proposed method is straightforward and reliable for truss damage identification. Especially,the method has good applicability for the truss under noisy environment and non-linear cases.
文摘Visual and pictorial materials are extensively used in teaching listening comprehension textbooks. Although the use of still image is currently implemented in some distinguished testing systems, video test is not a popular modality due to the fact that this kind of test may result in test-takers＇ confusion during the test. In the present study, a sample of 80 Iranian EFL （English as a Foreign Language） students was selected to compare their performance on three different modalities of listening test： audio-only test, pictorial （listening with still image test）, and visual （video） listening test. The analysis of one-way repeated measure ANOVA （Analysis of Variance） was used to compare the students＇ scores. The results of Bonferroni Post Hoc Test confirm that there were significant differences in scores among audio-only, pictorial, and visual tests. The results of this study highlight the greater performance of students in pictorial listening test which is statistically significant.
