A semi-fragile content authentication algorithm is proposed for low bit-rate H.264/AVC video in VLC domain. Utilizing the intra prediction mode and coded block pattern in VLC domain, the proposed algorithm chooses tho...A semi-fragile content authentication algorithm is proposed for low bit-rate H.264/AVC video in VLC domain. Utilizing the intra prediction mode and coded block pattern in VLC domain, the proposed algorithm chooses those macro-blocks from which the signature is extracted and constructs content signature at macro-block level according to the relationship among the energies of quantized low-frequency coefficients of sub-macroblocks. The signature is embedded by modifying the trailing coefficients. The experimental results show that the proposed algorithm performs well in visual quality impact and keep the bit-rate basically unchanged. In addition, the algorithm can embed signatures into I, P, B slices simultaneously and remarkably enhances the watermark capacity. By verifying the extracted signature, the algorithm can detect and locate video tampering efficiently.展开更多
A novel multiple watermarks cooperative authentication algorithm was presented for image contents authentication.This algorithm is able to extract multiple features from the image wavelet domain,which is based on that...A novel multiple watermarks cooperative authentication algorithm was presented for image contents authentication.This algorithm is able to extract multiple features from the image wavelet domain,which is based on that the t watermarks are generated.Moreover,a new watermark embedding method,using the space geometric model,was proposed,in order to effectively tackle with the mutual influences problem among t watermarks.Specifically,the incidental tampering location,the classification of intentional content tampering and the incidental modification can be achieved via mutual cooperation of the t watermarks.Both the theoretical analysis and simulations results validate the feasibility and efficacy of the proposed algorithm.展开更多
In the past few years, the notion of task complexity has been receiving substantial attention in the field of second language acquisition. This paper explores task complexity from the cognitive perspective by analyzin...In the past few years, the notion of task complexity has been receiving substantial attention in the field of second language acquisition. This paper explores task complexity from the cognitive perspective by analyzing two studies with Skehan＇s limited capacity hypothesis and Robinson＇s cognition hypothesis. The two studies, namely You-Jin Kim＇s （2012） and Mirdamadi and Jong （2015）, explore on how linguistic complexity affects language performance. Two hypotheses, Skehan＇s limited capacity hypothesis and Robinson＇s cognition hypothesis, explain the two studies from the cognitive perspective by predicting either that increasing task complexity reduces a pool of attentional capacity during task performance or that increasing complex tasks promotes greater accuracy and complexity of speech and writing. It is suggested that language teaching, syllabus designing in particular, should be based on the basis of task complexity.展开更多
A novel semi-fragile watermarking scheme for the content authentication of images using wavelet transform(WT) is presented in this paper.It is tolerant to the embedded wavelet image compression methods based on WT suc...A novel semi-fragile watermarking scheme for the content authentication of images using wavelet transform(WT) is presented in this paper.It is tolerant to the embedded wavelet image compression methods based on WT such as embedded zerotree wavelet(EZW) ,set partitioning in hierarchical trees(SPIHT) and embedded block coding with optimized truncation(EBCOT) in JPEG2000 to a pre-determined bit-plane,but is sensitive to all other malicious attacks.The image features are generated from the lowest-frequency(LF) subband of the original image as the embedded watermark.The watermark is embedded into the pre-determined bit-plane by adjusting the corresponding values in the given subband.In the process of watermarking authentication,we compare the image features generated from the LF subband of the received image with the embedded watermarking information(the image features of the original image) extracted from the pre-determined bit-plane in the given subband of the received image to decide whether the image is attacked maliciously or processed acceptably(the embedded wavelet compression) .The most important advantage of our watermarking scheme is that the watermark information can be extracted from the watermarked image when detecting watermark,so the received image authentication needs no information about the original image or watermark.Experimental results prove the effectiveness of our proposed watermarking scheme.展开更多
For effective second language learning, the compatibility between the learners' learning preferences and teachers' instructional approaches in classroom learning activities is of crucial importance. However, t...For effective second language learning, the compatibility between the learners' learning preferences and teachers' instructional approaches in classroom learning activities is of crucial importance. However, there is some incongruity in between in the college EFL classroom in China, which has very much hindered students' language learning progress. Based on statistical survey and classroom observations, the paper examines the general differences in college students' learning preferences, presents some findings on the various conflicting situations, and discusses its implications for second language learning and teaching.展开更多
基金This paper is sponsored by the National Natural Science Foundation of China （No. 60802057, 61071153）, National 863 Plan of China （ 2009AA01Z407 ）, Shanghai Rising-Star Program （10QA1403700）, and Shanghai Educational Development Foundation.
文摘A semi-fragile content authentication algorithm is proposed for low bit-rate H.264/AVC video in VLC domain. Utilizing the intra prediction mode and coded block pattern in VLC domain, the proposed algorithm chooses those macro-blocks from which the signature is extracted and constructs content signature at macro-block level according to the relationship among the energies of quantized low-frequency coefficients of sub-macroblocks. The signature is embedded by modifying the trailing coefficients. The experimental results show that the proposed algorithm performs well in visual quality impact and keep the bit-rate basically unchanged. In addition, the algorithm can embed signatures into I, P, B slices simultaneously and remarkably enhances the watermark capacity. By verifying the extracted signature, the algorithm can detect and locate video tampering efficiently.
基金Project(2012BAH09B02) supported by the National Science and Technology Support Program,ChinaProjects(12JJ3068,12JJ2041) supported by the Natural Science Fundation of Hunan Province,China
文摘A novel multiple watermarks cooperative authentication algorithm was presented for image contents authentication.This algorithm is able to extract multiple features from the image wavelet domain,which is based on that the t watermarks are generated.Moreover,a new watermark embedding method,using the space geometric model,was proposed,in order to effectively tackle with the mutual influences problem among t watermarks.Specifically,the incidental tampering location,the classification of intentional content tampering and the incidental modification can be achieved via mutual cooperation of the t watermarks.Both the theoretical analysis and simulations results validate the feasibility and efficacy of the proposed algorithm.
文摘In the past few years, the notion of task complexity has been receiving substantial attention in the field of second language acquisition. This paper explores task complexity from the cognitive perspective by analyzing two studies with Skehan＇s limited capacity hypothesis and Robinson＇s cognition hypothesis. The two studies, namely You-Jin Kim＇s （2012） and Mirdamadi and Jong （2015）, explore on how linguistic complexity affects language performance. Two hypotheses, Skehan＇s limited capacity hypothesis and Robinson＇s cognition hypothesis, explain the two studies from the cognitive perspective by predicting either that increasing task complexity reduces a pool of attentional capacity during task performance or that increasing complex tasks promotes greater accuracy and complexity of speech and writing. It is suggested that language teaching, syllabus designing in particular, should be based on the basis of task complexity.
文摘A novel semi-fragile watermarking scheme for the content authentication of images using wavelet transform(WT) is presented in this paper.It is tolerant to the embedded wavelet image compression methods based on WT such as embedded zerotree wavelet(EZW) ,set partitioning in hierarchical trees(SPIHT) and embedded block coding with optimized truncation(EBCOT) in JPEG2000 to a pre-determined bit-plane,but is sensitive to all other malicious attacks.The image features are generated from the lowest-frequency(LF) subband of the original image as the embedded watermark.The watermark is embedded into the pre-determined bit-plane by adjusting the corresponding values in the given subband.In the process of watermarking authentication,we compare the image features generated from the LF subband of the received image with the embedded watermarking information(the image features of the original image) extracted from the pre-determined bit-plane in the given subband of the received image to decide whether the image is attacked maliciously or processed acceptably(the embedded wavelet compression) .The most important advantage of our watermarking scheme is that the watermark information can be extracted from the watermarked image when detecting watermark,so the received image authentication needs no information about the original image or watermark.Experimental results prove the effectiveness of our proposed watermarking scheme.
基金Research on the Refor med Teaching and Learning in the 21st Century Project issued by the Education Commitee of Heilongjiang Province 2006
文摘For effective second language learning, the compatibility between the learners' learning preferences and teachers' instructional approaches in classroom learning activities is of crucial importance. However, there is some incongruity in between in the college EFL classroom in China, which has very much hindered students' language learning progress. Based on statistical survey and classroom observations, the paper examines the general differences in college students' learning preferences, presents some findings on the various conflicting situations, and discusses its implications for second language learning and teaching.
