To compress hyperspectral images, a low complexity discrete cosine transform （DCT）-based distributed source coding （DSC） scheme with Gray code is proposed. Unlike most of the existing DSC schemes, which utilize tr...To compress hyperspectral images, a low complexity discrete cosine transform （DCT）-based distributed source coding （DSC） scheme with Gray code is proposed. Unlike most of the existing DSC schemes, which utilize transform in spatial domain, the proposed algorithm applies transform in spectral domain. Set-partitioning-based approach is applied to reorganize DCT coefficients into waveletlike tree structure and extract the sign, refinement, and significance bitplanes. The extracted refinement bits are Gray encoded. Because of the dependency along the line dimension of hyperspectral images, low density paritycheck-（LDPC）-based Slepian-Wolf coder is adopted to implement the DSC strategy. Experimental results on airborne visible/infrared imaging spectrometer （AVIRIS） dataset show that the proposed paradigm achieves up to 6 dB improvement over DSC-based coders which apply transform in spatial domain, with significantly reduced computational complexity and memory storage.展开更多
In the present communication, we have obtained the optimum probability distribution with which the messages should be delivered so that the average redundancy of the source is minimized. Here, we have taken the case o...In the present communication, we have obtained the optimum probability distribution with which the messages should be delivered so that the average redundancy of the source is minimized. Here, we have taken the case of various generalized mean codeword lengths. Moreover, the upper bound to these codeword lengths has been found for the case of Huffman encoding.展开更多
Popular video coding standards like H.264 and MPEG working on the principle of motion-compensated pre-dictive coding demand much of the computational resources at the encoder increasing its complexity. Such bulky enco...Popular video coding standards like H.264 and MPEG working on the principle of motion-compensated pre-dictive coding demand much of the computational resources at the encoder increasing its complexity. Such bulky encoders are not suitable for applications like wireless low power surveillance, multimedia sensor networks, wireless PC cameras, mobile camera phones etc. New video coding scheme based on the principle of distributed source coding is looked upon in this paper. This scheme supports a low complexity encoder, at the same time trying to achieve the rate distortion performance of conventional video codecs. Current im-plementation uses LDPC codes for syndrome coding.展开更多
One way to speed up the execution of sequential programs is to divide them into concurrent segments and execute such segments in a parallel manner over a distributed computing environment.We argue that the execution s...One way to speed up the execution of sequential programs is to divide them into concurrent segments and execute such segments in a parallel manner over a distributed computing environment.We argue that the execution speedup primarily depends on the concurrency degree between the identified segments as well as communication overhead between the segments.To guarantee the best speedup,we have to obtain the maximum possible concurrency degree between the identified segments,taking communication overhead into consideration.Existing code distributor and multi-threading approaches do not fulfill such requirements;hence,they cannot provide expected distributability gains in advance.To overcome such limitations,we propose a novel approach for verifying the distributability of sequential object-oriented programs.The proposed approach enables users to see the maximum speedup gains before the actual distributability implementations,as it computes an objective function which is used to measure different distribution values from the same program,taking into consideration both remote and sequential calls.Experimental results showed that the proposed approach successfully determines the distributability of different real-life software applications compared with their real-life sequential and distributed implementations.展开更多
基金supported by the National Natural Science Foundationof China (60702012)the Scientific Research Foundation for the Re-turned Overseas Chinese Scholars, State Education Ministry
文摘To compress hyperspectral images, a low complexity discrete cosine transform （DCT）-based distributed source coding （DSC） scheme with Gray code is proposed. Unlike most of the existing DSC schemes, which utilize transform in spatial domain, the proposed algorithm applies transform in spectral domain. Set-partitioning-based approach is applied to reorganize DCT coefficients into waveletlike tree structure and extract the sign, refinement, and significance bitplanes. The extracted refinement bits are Gray encoded. Because of the dependency along the line dimension of hyperspectral images, low density paritycheck-（LDPC）-based Slepian-Wolf coder is adopted to implement the DSC strategy. Experimental results on airborne visible/infrared imaging spectrometer （AVIRIS） dataset show that the proposed paradigm achieves up to 6 dB improvement over DSC-based coders which apply transform in spatial domain, with significantly reduced computational complexity and memory storage.
基金Supported by the National Natural Science Foundation of China （No. 60532060 60672117）, the Program for Changjiang Scholars and Innovative Research Team in University （PCS1TR）.
文摘In the present communication, we have obtained the optimum probability distribution with which the messages should be delivered so that the average redundancy of the source is minimized. Here, we have taken the case of various generalized mean codeword lengths. Moreover, the upper bound to these codeword lengths has been found for the case of Huffman encoding.
文摘Popular video coding standards like H.264 and MPEG working on the principle of motion-compensated pre-dictive coding demand much of the computational resources at the encoder increasing its complexity. Such bulky encoders are not suitable for applications like wireless low power surveillance, multimedia sensor networks, wireless PC cameras, mobile camera phones etc. New video coding scheme based on the principle of distributed source coding is looked upon in this paper. This scheme supports a low complexity encoder, at the same time trying to achieve the rate distortion performance of conventional video codecs. Current im-plementation uses LDPC codes for syndrome coding.
文摘One way to speed up the execution of sequential programs is to divide them into concurrent segments and execute such segments in a parallel manner over a distributed computing environment.We argue that the execution speedup primarily depends on the concurrency degree between the identified segments as well as communication overhead between the segments.To guarantee the best speedup,we have to obtain the maximum possible concurrency degree between the identified segments,taking communication overhead into consideration.Existing code distributor and multi-threading approaches do not fulfill such requirements;hence,they cannot provide expected distributability gains in advance.To overcome such limitations,we propose a novel approach for verifying the distributability of sequential object-oriented programs.The proposed approach enables users to see the maximum speedup gains before the actual distributability implementations,as it computes an objective function which is used to measure different distribution values from the same program,taking into consideration both remote and sequential calls.Experimental results showed that the proposed approach successfully determines the distributability of different real-life software applications compared with their real-life sequential and distributed implementations.
