Objective to explore dynamic characteristics of the HIV mother to child transmission （MTCT） epidemic in China.Methods A deterministic dynamic transmission model was used to determine the effect of key parameters on ...Objective to explore dynamic characteristics of the HIV mother to child transmission （MTCT） epidemic in China.Methods A deterministic dynamic transmission model was used to determine the effect of key parameters on the likely long-term trends of the HIV MTCT epidemic in China.Matlab 7.0 was used to develop the model.Results The number of the susceptibles （S）,the transmission rate （β）,and the screening proportion （α） of HIV positive pregnant women have the greatest impact on the HIV MTCT epidemic in China.The growth of the MTCT epidemic in China could not be controlled only by decreasing the MTCT transmission rate.The prevalence of HIV positive women should be reduced and more pregnant women should be tested for HIV.Conclusion Prevention of MTCT （PMTCT） should focus not only on the reduction of HIV transmission rates and incidences of HIV among women but also on the increase of HIV testing for pregnant women.The most cost-effective PMTCT means for China should be investigated in future studies.展开更多
The acquired hyperspectral images （HSIs） are inherently attected by noise wlm Dano-varylng level, which cannot be removed easily by current approaches. In this study, a new denoising method is proposed for removing ...The acquired hyperspectral images （HSIs） are inherently attected by noise wlm Dano-varylng level, which cannot be removed easily by current approaches. In this study, a new denoising method is proposed for removing such kind of noise by smoothing spectral signals in the transformed multi- scale domain. Specifically, the proposed method includes three procedures： 1 ） applying a discrete wavelet transform （DWT） to each band; 2） performing cubic spline smoothing on each noisy coeffi- cient vector along the spectral axis; 3 ） reconstructing each band by an inverse DWT. In order to adapt to the band-varying noise statistics of HSIs, the noise covariance is estimated to control the smoothing degree at different spectra｜ positions. Generalized cross validation （GCV） is employed to choose the smoothing parameter during the optimization. The experimental results on simulated and real HSIs demonstrate that the proposed method can be well adapted to band-varying noise statistics of noisy HSIs and also can well preserve the spectral and spatial features.展开更多
A runtime reconfigurable very-large-scale integration （VLSI） architecture for image and video scaling by arbitrary factors with good antialiasing performance is presented in this paper. Video scal- ing is used in a ...A runtime reconfigurable very-large-scale integration （VLSI） architecture for image and video scaling by arbitrary factors with good antialiasing performance is presented in this paper. Video scal- ing is used in a wide range of applications from broadcast, medical imaging and high-resolution video effects to video surveillance, and video conferencing. Many algorithms have been proposed for these applications, such as piecewise polynomial kernels and windowed sinc kernels. The sum of three shifted versions of a B-spline function, whose weights can be adjusted for different applications, is adopted as the main filter. The proposed algorithm is confirmed to be effective on image scaling ap- plications and also verified by many widely acknowledged image quality measures. The reconfigu- rable hardware architecture constitutes an arbitrary scaler with low resource consumption and high performance targeted for field programmable gate array （FPGA） devices. The scaling factor can be changed on-the-fly, and the filter can also be changed during runtime within a unifying framework.展开更多
In this paper, a high-performance and low-complexity luminance transient improvement （LTI） algorithm is proposed and efficiently implemented on field programmable gate army （FPGA） devices, which can be widely used...In this paper, a high-performance and low-complexity luminance transient improvement （LTI） algorithm is proposed and efficiently implemented on field programmable gate army （FPGA） devices, which can be widely used to enhance the sharpness of digital video. The proposed algorithm generates the cor- rection signal by using the difference of the outputs of two Gaussian filters with different variances, and then modulates the correction signal adaptively according to the local contrast information of video frames. A 2-D min/max nonlinear filter is employed to suppress overshoots around edges. The proposed algorithm is thoroughly confirmed by experiments and compared with other algorithms on irrkages, which produces steeper edges and better visual quality while suppressing noise and artifacts. And the hardware architecture suitable for FPGA implementation is optimized based on the property of the algorithm and proves to be effective and efficient in many respects, such as resource consumption, performance and reconfigura- bility. The specific implementation details on both Xilinx and Ahera FPGA devices are also described in this paper.展开更多
A k-shortest path based algorithm considering layout density and signal integrity for good buffer candidatelocations is proposed in this paper. Theoretical results for computing the maximal distance betweenbuffers are...A k-shortest path based algorithm considering layout density and signal integrity for good buffer candidatelocations is proposed in this paper. Theoretical results for computing the maximal distance betweenbuffers are derived under the timing, noise and slew rate constraints. By modifying the traditional uniformwire segmenting strategy and considering the impact of tile size on density penalty function, this work proposesk-shortest path algorithm to find the buffer insertion candidate locations. The experiments show thatthe buffers inserted can significantly optimize the design density, alleviate signal degradation, save thenumber of buffers inserted and the overall run time.展开更多
An explicit lighting estimation from a single image of Lambertian objects is influenced by two factors： data incompletion and noise contamination. Measurement of lighting consistency purely using the orthogonal spher...An explicit lighting estimation from a single image of Lambertian objects is influenced by two factors： data incompletion and noise contamination. Measurement of lighting consistency purely using the orthogonal spherical harmonic basis cannot achieve an accurate estimation. We present a novel signal-processing framework to represent the lighting field. We construct a redundant spherical harmonic frame with geometric symmetry on the sphere S2. Spherical harmonic frames are defined over the generating rotation matrices about symmetry axes of finite symmetry subgroups of SO（3）, and the generating functions are spherical harmonic basis functions. Compared with the orthogonal spherical harmonic basis, the redundant spherical harmonic frames not only describe the multidirectional lighting distribution intuitively, but also resist the noise theoretically. Subsequently, we analyze the relationship of the irradiance to the incoming radiance in terms of spherical harmonic frames, and reconstruct the lighting function filtered by the Lambertian BRDF （bidirectional reflectance distribution function）. The experiments show that the frame coefficients of spherical harmonic frames can better characterize the complex lighting environments finely and robustly.展开更多
By introducing a novel spatial-spectral domain mixing prior, this paper establishes a Maximum a posteriori （MAP） framework for hyperspectral images （HSIs） denoising. The proposed mixing prior takes advantage of di...By introducing a novel spatial-spectral domain mixing prior, this paper establishes a Maximum a posteriori （MAP） framework for hyperspectral images （HSIs） denoising. The proposed mixing prior takes advantage of different properties of HSI in the spatial and spectral domain. Furthermore, we propose a spatially adaptive weighted prior combining smoothing prior and discontinuity-preserving prior in the spectral domain. The weights can be defined as a function of the spectral discontinuity measure （DM）. For minimizing the objective function, a half-quadratic optimization algorithm is used. The experimental results illustrate that our proposed model can get a higher signal-to-noise ratio （SNR） than using only smoothing prior or discontinuity-preserving prior.展开更多
基金supported by the mega-projects of national science research for the 11th Five-Year Plan (2008ZX10001-003)the Fogarty International Center, National Institutes of Health Office of the Director, Office of AIDS Research, National Cancer Institute,National Eye Institute,National Heart,Blood,and Lung Institute,National Institute of Dental & Craniofacial Research,National Institute On Drug Abuse,National Institute of Mental Health,National Institute of Allergy and Infectious Diseases Health,Office of Women’s Health Research, National Institute of Child Health and Human Development,through the International Clinical Research Fellows Program at Vanderbilt (R24 TW007988)
文摘Objective to explore dynamic characteristics of the HIV mother to child transmission （MTCT） epidemic in China.Methods A deterministic dynamic transmission model was used to determine the effect of key parameters on the likely long-term trends of the HIV MTCT epidemic in China.Matlab 7.0 was used to develop the model.Results The number of the susceptibles （S）,the transmission rate （β）,and the screening proportion （α） of HIV positive pregnant women have the greatest impact on the HIV MTCT epidemic in China.The growth of the MTCT epidemic in China could not be controlled only by decreasing the MTCT transmission rate.The prevalence of HIV positive women should be reduced and more pregnant women should be tested for HIV.Conclusion Prevention of MTCT （PMTCT） should focus not only on the reduction of HIV transmission rates and incidences of HIV among women but also on the increase of HIV testing for pregnant women.The most cost-effective PMTCT means for China should be investigated in future studies.
基金Supported by the National Natural Science Foundation of China(No.60972126,60921061)the State Key Program of National Natural Science of China(No.61032007)
文摘The acquired hyperspectral images （HSIs） are inherently attected by noise wlm Dano-varylng level, which cannot be removed easily by current approaches. In this study, a new denoising method is proposed for removing such kind of noise by smoothing spectral signals in the transformed multi- scale domain. Specifically, the proposed method includes three procedures： 1 ） applying a discrete wavelet transform （DWT） to each band; 2） performing cubic spline smoothing on each noisy coeffi- cient vector along the spectral axis; 3 ） reconstructing each band by an inverse DWT. In order to adapt to the band-varying noise statistics of HSIs, the noise covariance is estimated to control the smoothing degree at different spectra｜ positions. Generalized cross validation （GCV） is employed to choose the smoothing parameter during the optimization. The experimental results on simulated and real HSIs demonstrate that the proposed method can be well adapted to band-varying noise statistics of noisy HSIs and also can well preserve the spectral and spatial features.
基金Supported by the National Natural Science Foundation of China(No.60972126)the Joint Funds of the National Natural Science Foundation of China(No.U0935002/L05)+1 种基金the Beijing Municipal Natural Science Foundation(No.4102060)the State Key Program of the National Natural Science of China(No.61032007)
文摘A runtime reconfigurable very-large-scale integration （VLSI） architecture for image and video scaling by arbitrary factors with good antialiasing performance is presented in this paper. Video scal- ing is used in a wide range of applications from broadcast, medical imaging and high-resolution video effects to video surveillance, and video conferencing. Many algorithms have been proposed for these applications, such as piecewise polynomial kernels and windowed sinc kernels. The sum of three shifted versions of a B-spline function, whose weights can be adjusted for different applications, is adopted as the main filter. The proposed algorithm is confirmed to be effective on image scaling ap- plications and also verified by many widely acknowledged image quality measures. The reconfigu- rable hardware architecture constitutes an arbitrary scaler with low resource consumption and high performance targeted for field programmable gate array （FPGA） devices. The scaling factor can be changed on-the-fly, and the filter can also be changed during runtime within a unifying framework.
基金Supported by the National Science and Technology Support Projects Funded by Ministry of Science & Technology of China (No. 2006BAK07B04)
文摘In this paper, a high-performance and low-complexity luminance transient improvement （LTI） algorithm is proposed and efficiently implemented on field programmable gate army （FPGA） devices, which can be widely used to enhance the sharpness of digital video. The proposed algorithm generates the cor- rection signal by using the difference of the outputs of two Gaussian filters with different variances, and then modulates the correction signal adaptively according to the local contrast information of video frames. A 2-D min/max nonlinear filter is employed to suppress overshoots around edges. The proposed algorithm is thoroughly confirmed by experiments and compared with other algorithms on irrkages, which produces steeper edges and better visual quality while suppressing noise and artifacts. And the hardware architecture suitable for FPGA implementation is optimized based on the property of the algorithm and proves to be effective and efficient in many respects, such as resource consumption, performance and reconfigura- bility. The specific implementation details on both Xilinx and Ahera FPGA devices are also described in this paper.
基金Supported by the National Key Project of Scientific and Technical Supporting Programs (No. 2006BAK07B04).
文摘A k-shortest path based algorithm considering layout density and signal integrity for good buffer candidatelocations is proposed in this paper. Theoretical results for computing the maximal distance betweenbuffers are derived under the timing, noise and slew rate constraints. By modifying the traditional uniformwire segmenting strategy and considering the impact of tile size on density penalty function, this work proposesk-shortest path algorithm to find the buffer insertion candidate locations. The experiments show thatthe buffers inserted can significantly optimize the design density, alleviate signal degradation, save thenumber of buffers inserted and the overall run time.
基金supported by the National Natural Science Foundation of China under Grant No. 60972126the Joint Funds of the National Natural Science Foundation of China under Grant No. U0935002/L05+1 种基金the Beijing Municipal Natural Science Foundation of China under Grant No. 4102060the Key Program of National Natural Science Foundation of China under Grant No. 61032007
文摘An explicit lighting estimation from a single image of Lambertian objects is influenced by two factors： data incompletion and noise contamination. Measurement of lighting consistency purely using the orthogonal spherical harmonic basis cannot achieve an accurate estimation. We present a novel signal-processing framework to represent the lighting field. We construct a redundant spherical harmonic frame with geometric symmetry on the sphere S2. Spherical harmonic frames are defined over the generating rotation matrices about symmetry axes of finite symmetry subgroups of SO（3）, and the generating functions are spherical harmonic basis functions. Compared with the orthogonal spherical harmonic basis, the redundant spherical harmonic frames not only describe the multidirectional lighting distribution intuitively, but also resist the noise theoretically. Subsequently, we analyze the relationship of the irradiance to the incoming radiance in terms of spherical harmonic frames, and reconstruct the lighting function filtered by the Lambertian BRDF （bidirectional reflectance distribution function）. The experiments show that the frame coefficients of spherical harmonic frames can better characterize the complex lighting environments finely and robustly.
基金supported in part by the National Natural Science Foundation of China under Grant Nos. 60972126, 60921061the State Key Program of National Natural Science of China under Grant No. 61032007
文摘By introducing a novel spatial-spectral domain mixing prior, this paper establishes a Maximum a posteriori （MAP） framework for hyperspectral images （HSIs） denoising. The proposed mixing prior takes advantage of different properties of HSI in the spatial and spectral domain. Furthermore, we propose a spatially adaptive weighted prior combining smoothing prior and discontinuity-preserving prior in the spectral domain. The weights can be defined as a function of the spectral discontinuity measure （DM）. For minimizing the objective function, a half-quadratic optimization algorithm is used. The experimental results illustrate that our proposed model can get a higher signal-to-noise ratio （SNR） than using only smoothing prior or discontinuity-preserving prior.
