The ecological footprint （EF） model has received much attention as an assessment indicator for sustainable development in recent years. Firstly, the temporal changes of domestic timber production, imports and export...The ecological footprint （EF） model has received much attention as an assessment indicator for sustainable development in recent years. Firstly, the temporal changes of domestic timber production, imports and exports in China were analyzed from 1973 to 2003, the analysis results showed an apparent fluctuation in timber production during 1973-1995 but a decreasing trend during 1995-2002, an increasing trend in timber imports since 1995 especially after the implementation of the Natural Forest Protection Project （NFPP）, an decreasing trend year by year in timber exports since 1995. Secondly, this paper presented a time series analysis of actual forest area demand in the sustainable yield and production approach in China from 1973 to 2003, which includes both import and export forest area demand. The results showed the actual forest area demand simulated from the sustainable yield approach was slightly higher than that from the production approach during 1978-1988 and a little lower during 1989-2003; however, the actual forest area demands simulated by these two model approaches were larger than calculations that expressed in conventional forest EF. Meanwhile, the results indicated the forestry development in China during 1978-1988 was unsustainable due to overexploitation of forest stocking volumes, and China＇s forestry moved toward sustainable development since 1989 because forest resources are exploited at lower rates than they are regenerated. However, compared to forestry developed countries, the forestry development capacity in China is still lower. Finally, based on the model results we analyzed the relationships between forestry EF and the key policies, including trade policy, economic policy and forest conservation programs. In addition, several suggestions about reducing forestry EF and enhancing sustainable forestry development in China are given.展开更多
Sparsity constrained deconvolution can improve the resolution of band-limited seismic data compared to conventional deconvolution. However, such deconvolution methods result in nonunique solutions and suppress weak re...Sparsity constrained deconvolution can improve the resolution of band-limited seismic data compared to conventional deconvolution. However, such deconvolution methods result in nonunique solutions and suppress weak reflections. The Cauchy function, modified Cauchy function, and Huber function are commonly used constraint criteria in sparse deconvolution. We used numerical experiments to analyze the ability of sparsity constrained deconvolution to restore reflectivity sequences and protect weak reflections under different constraint criteria. The experimental results demonstrate that the performance of sparsity constrained deconvolution depends on the agreement between the constraint criteria and the probability distribution of the reflectivity sequences; furthermore, the modified Cauchy- constrained criterion protects the weak reflections better than the other criteria. Based on the model experiments, the probability distribution of the reflectivity sequences of carbonate and clastic formations is statistically analyzed by using well-logging data and then the modified Cauchy-constrained deconvolution is applied to real seismic data much improving the resolution.展开更多
基金This paper was supported by National Natural Science Foundation of China (70373044&30470302) and Rejuvenation Northeast Program of CAS
文摘The ecological footprint （EF） model has received much attention as an assessment indicator for sustainable development in recent years. Firstly, the temporal changes of domestic timber production, imports and exports in China were analyzed from 1973 to 2003, the analysis results showed an apparent fluctuation in timber production during 1973-1995 but a decreasing trend during 1995-2002, an increasing trend in timber imports since 1995 especially after the implementation of the Natural Forest Protection Project （NFPP）, an decreasing trend year by year in timber exports since 1995. Secondly, this paper presented a time series analysis of actual forest area demand in the sustainable yield and production approach in China from 1973 to 2003, which includes both import and export forest area demand. The results showed the actual forest area demand simulated from the sustainable yield approach was slightly higher than that from the production approach during 1978-1988 and a little lower during 1989-2003; however, the actual forest area demands simulated by these two model approaches were larger than calculations that expressed in conventional forest EF. Meanwhile, the results indicated the forestry development in China during 1978-1988 was unsustainable due to overexploitation of forest stocking volumes, and China＇s forestry moved toward sustainable development since 1989 because forest resources are exploited at lower rates than they are regenerated. However, compared to forestry developed countries, the forestry development capacity in China is still lower. Finally, based on the model results we analyzed the relationships between forestry EF and the key policies, including trade policy, economic policy and forest conservation programs. In addition, several suggestions about reducing forestry EF and enhancing sustainable forestry development in China are given.
基金supported by the Major Basic Research Development Program of China (973 Program)(No.2013CB228606)the National Science foundation of China (No.41174117)+1 种基金the National Major Science-Technology Project (No.2011ZX05031-001)Innovation Fund of PetroChina (No.2010D-5006-0301)
文摘Sparsity constrained deconvolution can improve the resolution of band-limited seismic data compared to conventional deconvolution. However, such deconvolution methods result in nonunique solutions and suppress weak reflections. The Cauchy function, modified Cauchy function, and Huber function are commonly used constraint criteria in sparse deconvolution. We used numerical experiments to analyze the ability of sparsity constrained deconvolution to restore reflectivity sequences and protect weak reflections under different constraint criteria. The experimental results demonstrate that the performance of sparsity constrained deconvolution depends on the agreement between the constraint criteria and the probability distribution of the reflectivity sequences; furthermore, the modified Cauchy- constrained criterion protects the weak reflections better than the other criteria. Based on the model experiments, the probability distribution of the reflectivity sequences of carbonate and clastic formations is statistically analyzed by using well-logging data and then the modified Cauchy-constrained deconvolution is applied to real seismic data much improving the resolution.
