The efficiency, precision, and denoising capabilities of reconstruction algorithms are critical to seismic data processing. Based on the Fourier-domain projection onto convex sets (POCS) algorithm, we propose an inv...The efficiency, precision, and denoising capabilities of reconstruction algorithms are critical to seismic data processing. Based on the Fourier-domain projection onto convex sets (POCS) algorithm, we propose an inversely proportional threshold model that defines the optimum threshold, in which the descent rate is larger than in the exponential threshold in the large-coefficient section and slower than in the exponential threshold in the small-coefficient section. Thus, the computation efficiency of the POCS seismic reconstruction greatly improves without affecting the reconstructed precision of weak reflections. To improve the flexibility of the inversely proportional threshold, we obtain the optimal threshold by using an adjustable dependent variable in the denominator of the inversely proportional threshold model. For random noise attenuation by completing the missing traces in seismic data reconstruction, we present a weighted reinsertion strategy based on the data-driven model that can be obtained by using the percentage of the data-driven threshold in each iteration in the threshold section. We apply the proposed POCS reconstruction method to 3D synthetic and field data. The results suggest that the inversely proportional threshold model improves the computational efficiency and precision compared with the traditional threshold models; furthermore, the proposed reinserting weight strategy increases the SNR of the reconstructed data.展开更多
A methodology for alignment of an X-ray image and a CT image, based on the Chamfer 3-4 distance transform and simulated annealing optimization algorithm is presented. Firstly, an initial transformation matrix is const...A methodology for alignment of an X-ray image and a CT image, based on the Chamfer 3-4 distance transform and simulated annealing optimization algorithm is presented. Firstly, an initial transformation matrix is constructed. For the convenience of computing, geometric models of the X-ray device to reconstruct the calibration matrix are used. Then, by defining the distance between the 3-D protective and the 2-D object image, we optimize this distance matching problem, using the simulated annealing algorithm. This method is also integrated into medical intra-operation, dealing with the data set acquired from 3-D image workstation and active navigation.展开更多
In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the un...In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square(RMS) error of distance was 0.000 7 mm.展开更多
A fast implementation of the convolution backprojection(CBP)algorithm in spotlight synthetic aperture radar(SAR)is presented based on the fast Fourier transform(FFT).Traditionally,the computation of the 'backpr...A fast implementation of the convolution backprojection(CBP)algorithm in spotlight synthetic aperture radar(SAR)is presented based on the fast Fourier transform(FFT).Traditionally,the computation of the 'backprojection' process is expensive,since resampling in the process is implemented by using the interpolation operation.By analyzing the relative location relationship among different pixels,the algorithm realizes the 'backprojection' using a series of FFTs instead of the interpolation operation.The point target simulation validates that the new algorithm accelerates the CBP algorithm,and the computational rate increases about 85%.展开更多
This work presents two different methods-nonlinear control method and adaptive control approach to achieve the modified projective synchronization of a new hyperchaotic system with known or unknown parameters.Based on...This work presents two different methods-nonlinear control method and adaptive control approach to achieve the modified projective synchronization of a new hyperchaotic system with known or unknown parameters.Based on Lyapunov stability theory,nonlinear control method is adopted when the parameters of driving and response systems are known beforehand;when the parameters are fully unknown,adaptive controllers and parameters update laws are proposed to synchronize two different hyperchaotic system and identify the unknown parameters.Moreover,the rate of synchronization can be regulated by adjusting the control gains designed in the controllers.The corresponding simulations are exploited to demonstrate the effectiveness of the proposed two methods.展开更多
First a general model for a three-step projection method is introduced, and second it has been applied to the approximation solvability of a system of nonlinear variational inequality problems in a Hilbert space setti...First a general model for a three-step projection method is introduced, and second it has been applied to the approximation solvability of a system of nonlinear variational inequality problems in a Hilbert space setting. Let H be a real Hilbert space and K be a nonempty closed convex subset of H. For arbitrarily chosen initial points x0, y0, z0 ∈ K, compute sequences xn, yn, zn such thatT : K→ H is a nonlinear mapping onto K. At last three-step models are applied to some variational inequality problems.展开更多
Aiming at the problem of soft sensing modeling for chemical process with strong nonlinearity and complexity,a soft sensing modeling method based on kernel-based orthogonal projections to latent structures(K-OPLS)is pr...Aiming at the problem of soft sensing modeling for chemical process with strong nonlinearity and complexity,a soft sensing modeling method based on kernel-based orthogonal projections to latent structures(K-OPLS)is proposed.Orthogonal projections to latent structures(O-PLS)is a general linear multi-variable data modeling method.It can eliminate systematic variations from descriptive variables(input)that are orthogonal to response variables(output).In the framework of O-PLS model,K-OPLS method maps descriptive variables to high-dimensional feature space by using“kernel technique”to calculate predictive components and response-orthogonal components in the model.Therefore,the K-OPLS method gives the non-linear relationship between the descriptor and the response variables,which improves the performance of the model and enhances the interpretability of the model to a certain extent.To verify the validity of K-OPLS method,it was applied to soft sensing modeling of component content of debutane tower base butane(C4),the quality index of the key product output for industrial fluidized catalytic cracking unit(FCCU)and H 2S and SO 2 concentration in sulfur recovery unit(SRU).Compared with support vector machines(SVM),least-squares support-vector machine(LS-SVM),support vector machine with principal component analysis(PCA-SVM),extreme learning machine(ELM),kernel based extreme learning machine(KELM)and kernel based extreme learning machine with principal component analysis(PCA-KELM)methods under the same conditions,the experimental results show that the K-OPLS method has superior modeling accuracy and good model generalization ability.展开更多
The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean ...The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean square(NLMS) algorithm in EC applications where the input signal is highly correlated. Since the APA with a constant step-size has to make compromise between the performance criteria 1) and 2), a variable step-size APA(VSS-APA) provides a more reliable solution. A nonparametric VSS-APA(NPVSS-APA) is proposed by recovering the background noise within the error signal instead of cancelling the a posteriori errors. The most problematic term of its variable step-size formula is the value of background noise power(BNP). The power difference between the desired signal and output signal, which equals the power of error signal statistically, has been considered the BNP estimate in a rough manner. Considering that the error signal consists of background noise and misalignment noise, a precise BNP estimate is achieved by multiplying the rough estimate with a corrective factor. After the analysis on the power ratio of misalignment noise to background noise of APA, the corrective factor is formulated depending on the projection order and the latest value of variable step-size. The new algorithm which does not require any a priori knowledge of EC environment has the advantage of easier controllability in practical application. The simulation results in the EC context indicate the accuracy of the proposed BNP estimate and the more effective behavior of the proposed algorithm compared with other versions of APA class.展开更多
Based on a high-resolution regional climate model (RegCM3) simulation over East Asia, future climate changes over the Miyun Reservoir in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) Spec...Based on a high-resolution regional climate model (RegCM3) simulation over East Asia, future climate changes over the Miyun Reservoir in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario are analyzed. The model simulation extends from 1951 to 2100 at a grid spacing of 25 km and is one-way nested within a global model of MIROC3.2_ hires (the Model for Interdisciplinary Research on Climate). The focus of the analysis is on the Watershed of Miyun Reservoir, the main water supply for Beijing in northern China. The results show that RegCM3 reproduces the observed temperature well but it overestimates precipitation over the region. Significant warming in the 21st century is simulated in the annual mean, December-January-February (DJF) and June-July-August (JJA), although with differences concerning the spatial distribution and magnitude. Changes in precipitation for the annual mean, DJF, and JJA also show differences. A prevailing increase of precipitation in DJF and a decrease of it in JJA is projected over the region, while little change in the annual mean is projected. Changes of the difference between precipitation and evapotranspiration to measure the potential water availability are also presented in the paper.展开更多
In the beginning, this template describes the actual situation on the market. As a second point, there is a description and a classification of the different kinds of innovation. The object of this template is a scien...In the beginning, this template describes the actual situation on the market. As a second point, there is a description and a classification of the different kinds of innovation. The object of this template is a scientific examination of the interrelation between innovation and the companies' future development. Today's markets are changing rapidly. The environment alters faster and faster. Business companies are forced to adapt to these changing conditions. They have to develop new and adjusted products to be successful on these markets. Companies are offering their products on markets. The more customers' requirements those products fulfil, the more likely they will be bought. Innovation can be described as a process of transforming a concept into a product, good, or service. Real innovation is seldom, though. More often, innovation is a result of a known solution being transferred into a new context. There are different forms of innovation. In general innovation can be classified in: basic innovation, product improving innovation, product adjusting innovation, imitation and pretended innovation. These different kinds of innovation can occur within a company as a process, or in a market as a newly developed product. The future of a company depends in many ways on the newly developed products, which in turn are depending on the needs of the customers. Those needs are not always known and needs could also be generated by inventing new technologies. Companies have to consider the development of new products and manufacturing processes in order to stay successful.展开更多
In this paper, using the variable coefficient generalized projected Rieatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. The...In this paper, using the variable coefficient generalized projected Rieatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. These solutions include Weierstrass function solution, solitary wave solutions, soliton-like solutions and trigonometric function solutions. Among these solutions, some are found for the first time. Because of the three or four arbitrary functions, rich localized excitations can be found.展开更多
Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, fiv...Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results showed the mean annual rainstorm days over the basin by the near-term, mid-term and long-term would increase from 3.9 days to 4.7, 4.9 and 5.1 days, and the mean annual maximum 3-day precipitation from 122 mm to 143, 146 and 149 mm, respectively. The flood hazard of the basin would become more severe, especially in the middle and lower reaches. Flood hazard grade 5 by the nearterm, mid-term and long-term would extend from 10.99% to 25.46, 28.14 and 29.75%, respectively.展开更多
The study reflects on previous World Bank and FAO reports that made the general recommendation to set both research and extension investment targets in developing countries at 1% of agricultural gross domestic product...The study reflects on previous World Bank and FAO reports that made the general recommendation to set both research and extension investment targets in developing countries at 1% of agricultural gross domestic product (AgGDP). In order to define proxies for country-specific extension investment targets, authors developed an extension investment model (EIM) based on socio-economic macro-indicators (poverty, undernourishment, access to information and population density) and a method to define estimates for cost increases related to climate change. These parameters helped estimating the demand for agricultural extension and investments required for it. Results showed that about half of the 94 developing and emerging countries should spend more than 1% of their respective share of GDP derived from agriculture and about a quarter of the countries, mostly in Africa and South East Asia, need to spend more than 2% of their AgGDP. The paper reveals significant differences in average investment requirements in different regions and shows the additional extension costs related to climate change and other areas that currently lack investment.展开更多
For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circ...For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circulation Model to the region of Peninsular Malaysia at fine grid resolution. This paper presents a desktop review of the state of climate change parameters, namely rainfall and river flow over the Peninsular Malaysia for the 2041-2050 projection period. Analysis of the results from the models shows there will be a substantial increase in mean monthly precipitation over the North East Coastal region from historical 259.5 mm to 281.5 mm, from 289.0 mm to 299.0 mm and 221.8 mm to 239.5 mm over Terengganu and Kelantan, respectively. Meanwhile, for river flow projection, it will be an expected increase in interannual and intraseasonal variability with increased hydrologic extremes (higher high flows, and lower low flows) at Kelantan, Pahang, Terengganu, and Kedah watersheds in the future.展开更多
A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the ...A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.展开更多
An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to...An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to coating on its surface and deposition at dead zone area by fine magnetite particles.Hence, the effective density of coal particle increases and the position of coal particle changes accordingly. In this work, an attempt was made to predict the position of coal particle in non-bubbling condition dense medium fluidized bed system. Coal particles of different shape such as cubical, rectangular prism,spherical and triangular prism with different projected area and density were used. The results show that the position of coal particle in air dense medium fluidized bed follows descending order with respect to the increase of density, projected area of coal particle and different shapes(i.e., triangular prism, cubical,rectangular prism and spherical). Empirical mathematical correlations were developed to predict the position of coal particle.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U1262207 and 41204101)the National Science and Technology Major Project of China(No.2011ZX05019-006)
文摘The efficiency, precision, and denoising capabilities of reconstruction algorithms are critical to seismic data processing. Based on the Fourier-domain projection onto convex sets (POCS) algorithm, we propose an inversely proportional threshold model that defines the optimum threshold, in which the descent rate is larger than in the exponential threshold in the large-coefficient section and slower than in the exponential threshold in the small-coefficient section. Thus, the computation efficiency of the POCS seismic reconstruction greatly improves without affecting the reconstructed precision of weak reflections. To improve the flexibility of the inversely proportional threshold, we obtain the optimal threshold by using an adjustable dependent variable in the denominator of the inversely proportional threshold model. For random noise attenuation by completing the missing traces in seismic data reconstruction, we present a weighted reinsertion strategy based on the data-driven model that can be obtained by using the percentage of the data-driven threshold in each iteration in the threshold section. We apply the proposed POCS reconstruction method to 3D synthetic and field data. The results suggest that the inversely proportional threshold model improves the computational efficiency and precision compared with the traditional threshold models; furthermore, the proposed reinserting weight strategy increases the SNR of the reconstructed data.
基金The National Natural Science Foundation of China (60272045) the Key Project of Ministry of Education of China.
文摘A methodology for alignment of an X-ray image and a CT image, based on the Chamfer 3-4 distance transform and simulated annealing optimization algorithm is presented. Firstly, an initial transformation matrix is constructed. For the convenience of computing, geometric models of the X-ray device to reconstruct the calibration matrix are used. Then, by defining the distance between the 3-D protective and the 2-D object image, we optimize this distance matching problem, using the simulated annealing algorithm. This method is also integrated into medical intra-operation, dealing with the data set acquired from 3-D image workstation and active navigation.
基金Supported by the National Natural Science Foundation of China(No.51105273)
文摘In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square(RMS) error of distance was 0.000 7 mm.
基金Supported by the National Natural Science Foundation of China(61071165)the Aeronautical Science Foundation of China(20080152004)+1 种基金the Ph.D.Programs Foundation of Ministry of Education of China(20070280531)the Program for New Century Excellent Talents in University(NCET-09-0069)~~
文摘A fast implementation of the convolution backprojection(CBP)algorithm in spotlight synthetic aperture radar(SAR)is presented based on the fast Fourier transform(FFT).Traditionally,the computation of the 'backprojection' process is expensive,since resampling in the process is implemented by using the interpolation operation.By analyzing the relative location relationship among different pixels,the algorithm realizes the 'backprojection' using a series of FFTs instead of the interpolation operation.The point target simulation validates that the new algorithm accelerates the CBP algorithm,and the computational rate increases about 85%.
基金National Natural Science Foundation of China(No.60874113)
文摘This work presents two different methods-nonlinear control method and adaptive control approach to achieve the modified projective synchronization of a new hyperchaotic system with known or unknown parameters.Based on Lyapunov stability theory,nonlinear control method is adopted when the parameters of driving and response systems are known beforehand;when the parameters are fully unknown,adaptive controllers and parameters update laws are proposed to synchronize two different hyperchaotic system and identify the unknown parameters.Moreover,the rate of synchronization can be regulated by adjusting the control gains designed in the controllers.The corresponding simulations are exploited to demonstrate the effectiveness of the proposed two methods.
文摘First a general model for a three-step projection method is introduced, and second it has been applied to the approximation solvability of a system of nonlinear variational inequality problems in a Hilbert space setting. Let H be a real Hilbert space and K be a nonempty closed convex subset of H. For arbitrarily chosen initial points x0, y0, z0 ∈ K, compute sequences xn, yn, zn such thatT : K→ H is a nonlinear mapping onto K. At last three-step models are applied to some variational inequality problems.
基金National Natural Science Foundation of China(No.51467008)。
文摘Aiming at the problem of soft sensing modeling for chemical process with strong nonlinearity and complexity,a soft sensing modeling method based on kernel-based orthogonal projections to latent structures(K-OPLS)is proposed.Orthogonal projections to latent structures(O-PLS)is a general linear multi-variable data modeling method.It can eliminate systematic variations from descriptive variables(input)that are orthogonal to response variables(output).In the framework of O-PLS model,K-OPLS method maps descriptive variables to high-dimensional feature space by using“kernel technique”to calculate predictive components and response-orthogonal components in the model.Therefore,the K-OPLS method gives the non-linear relationship between the descriptor and the response variables,which improves the performance of the model and enhances the interpretability of the model to a certain extent.To verify the validity of K-OPLS method,it was applied to soft sensing modeling of component content of debutane tower base butane(C4),the quality index of the key product output for industrial fluidized catalytic cracking unit(FCCU)and H 2S and SO 2 concentration in sulfur recovery unit(SRU).Compared with support vector machines(SVM),least-squares support-vector machine(LS-SVM),support vector machine with principal component analysis(PCA-SVM),extreme learning machine(ELM),kernel based extreme learning machine(KELM)and kernel based extreme learning machine with principal component analysis(PCA-KELM)methods under the same conditions,the experimental results show that the K-OPLS method has superior modeling accuracy and good model generalization ability.
文摘The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean square(NLMS) algorithm in EC applications where the input signal is highly correlated. Since the APA with a constant step-size has to make compromise between the performance criteria 1) and 2), a variable step-size APA(VSS-APA) provides a more reliable solution. A nonparametric VSS-APA(NPVSS-APA) is proposed by recovering the background noise within the error signal instead of cancelling the a posteriori errors. The most problematic term of its variable step-size formula is the value of background noise power(BNP). The power difference between the desired signal and output signal, which equals the power of error signal statistically, has been considered the BNP estimate in a rough manner. Considering that the error signal consists of background noise and misalignment noise, a precise BNP estimate is achieved by multiplying the rough estimate with a corrective factor. After the analysis on the power ratio of misalignment noise to background noise of APA, the corrective factor is formulated depending on the projection order and the latest value of variable step-size. The new algorithm which does not require any a priori knowledge of EC environment has the advantage of easier controllability in practical application. The simulation results in the EC context indicate the accuracy of the proposed BNP estimate and the more effective behavior of the proposed algorithm compared with other versions of APA class.
基金supported by the National Natural Science Foundation of China under Grant 40975041the National Basic Research Program of China under Grant 2009CB421407
文摘Based on a high-resolution regional climate model (RegCM3) simulation over East Asia, future climate changes over the Miyun Reservoir in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario are analyzed. The model simulation extends from 1951 to 2100 at a grid spacing of 25 km and is one-way nested within a global model of MIROC3.2_ hires (the Model for Interdisciplinary Research on Climate). The focus of the analysis is on the Watershed of Miyun Reservoir, the main water supply for Beijing in northern China. The results show that RegCM3 reproduces the observed temperature well but it overestimates precipitation over the region. Significant warming in the 21st century is simulated in the annual mean, December-January-February (DJF) and June-July-August (JJA), although with differences concerning the spatial distribution and magnitude. Changes in precipitation for the annual mean, DJF, and JJA also show differences. A prevailing increase of precipitation in DJF and a decrease of it in JJA is projected over the region, while little change in the annual mean is projected. Changes of the difference between precipitation and evapotranspiration to measure the potential water availability are also presented in the paper.
文摘In the beginning, this template describes the actual situation on the market. As a second point, there is a description and a classification of the different kinds of innovation. The object of this template is a scientific examination of the interrelation between innovation and the companies' future development. Today's markets are changing rapidly. The environment alters faster and faster. Business companies are forced to adapt to these changing conditions. They have to develop new and adjusted products to be successful on these markets. Companies are offering their products on markets. The more customers' requirements those products fulfil, the more likely they will be bought. Innovation can be described as a process of transforming a concept into a product, good, or service. Real innovation is seldom, though. More often, innovation is a result of a known solution being transferred into a new context. There are different forms of innovation. In general innovation can be classified in: basic innovation, product improving innovation, product adjusting innovation, imitation and pretended innovation. These different kinds of innovation can occur within a company as a process, or in a market as a newly developed product. The future of a company depends in many ways on the newly developed products, which in turn are depending on the needs of the customers. Those needs are not always known and needs could also be generated by inventing new technologies. Companies have to consider the development of new products and manufacturing processes in order to stay successful.
基金The project supported by National Natural Science Foundation of China undcr Grant No. 10172056 .
文摘In this paper, using the variable coefficient generalized projected Rieatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. These solutions include Weierstrass function solution, solitary wave solutions, soliton-like solutions and trigonometric function solutions. Among these solutions, some are found for the first time. Because of the three or four arbitrary functions, rich localized excitations can be found.
基金supported by the National Technology R&D Program (Grant nos. 2006BAD20B05 and 2008BAK50B06)
文摘Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results showed the mean annual rainstorm days over the basin by the near-term, mid-term and long-term would increase from 3.9 days to 4.7, 4.9 and 5.1 days, and the mean annual maximum 3-day precipitation from 122 mm to 143, 146 and 149 mm, respectively. The flood hazard of the basin would become more severe, especially in the middle and lower reaches. Flood hazard grade 5 by the nearterm, mid-term and long-term would extend from 10.99% to 25.46, 28.14 and 29.75%, respectively.
文摘The study reflects on previous World Bank and FAO reports that made the general recommendation to set both research and extension investment targets in developing countries at 1% of agricultural gross domestic product (AgGDP). In order to define proxies for country-specific extension investment targets, authors developed an extension investment model (EIM) based on socio-economic macro-indicators (poverty, undernourishment, access to information and population density) and a method to define estimates for cost increases related to climate change. These parameters helped estimating the demand for agricultural extension and investments required for it. Results showed that about half of the 94 developing and emerging countries should spend more than 1% of their respective share of GDP derived from agriculture and about a quarter of the countries, mostly in Africa and South East Asia, need to spend more than 2% of their AgGDP. The paper reveals significant differences in average investment requirements in different regions and shows the additional extension costs related to climate change and other areas that currently lack investment.
文摘For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circulation Model to the region of Peninsular Malaysia at fine grid resolution. This paper presents a desktop review of the state of climate change parameters, namely rainfall and river flow over the Peninsular Malaysia for the 2041-2050 projection period. Analysis of the results from the models shows there will be a substantial increase in mean monthly precipitation over the North East Coastal region from historical 259.5 mm to 281.5 mm, from 289.0 mm to 299.0 mm and 221.8 mm to 239.5 mm over Terengganu and Kelantan, respectively. Meanwhile, for river flow projection, it will be an expected increase in interannual and intraseasonal variability with increased hydrologic extremes (higher high flows, and lower low flows) at Kelantan, Pahang, Terengganu, and Kedah watersheds in the future.
基金Project(2010-0020163)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education
文摘A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.
文摘An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to coating on its surface and deposition at dead zone area by fine magnetite particles.Hence, the effective density of coal particle increases and the position of coal particle changes accordingly. In this work, an attempt was made to predict the position of coal particle in non-bubbling condition dense medium fluidized bed system. Coal particles of different shape such as cubical, rectangular prism,spherical and triangular prism with different projected area and density were used. The results show that the position of coal particle in air dense medium fluidized bed follows descending order with respect to the increase of density, projected area of coal particle and different shapes(i.e., triangular prism, cubical,rectangular prism and spherical). Empirical mathematical correlations were developed to predict the position of coal particle.