For sustainable water resource management,it is important to determine the relationship between streamfl ow and other variables that infl uence availability of water resources.However,many catchments do not have suffi...For sustainable water resource management,it is important to determine the relationship between streamfl ow and other variables that infl uence availability of water resources.However,many catchments do not have suffi cient data to allow for a more detailed study of these relationships.We faced a similar challenge in the Chengcun Basin(limited historical data: from 1986–1999); and therefore we used a new approach to overcome this.We found that,using nonparametric trend methods in conjunction with the climate elasticity analyses and the 2D visualization of hydrologic data,it is possible to assess the relationships between streamfl ow and other hydro-climatic variables.In the past,streamfl ow trends in the basin were more correlated with precipitation than with potential evapotranspiration(PET).In addition,there is a gradual shift in the hydrological regime of the catchment,which may affect the occurrence of available water resources and activities that depend on them.In addition,based on our climate sensitivity analyses,the streamfl ow is dependent and more sensitive to variations in precipitation than to PET(δQ=0.79δP+0.42δE; precipitation elasticity,ε P=1.32; PET elasticity,ε E=-2.10).Therefore pending more detailed studies,the use of our approach will provide a rapid means to assess the variation of water resources(streamfl ow)in a watershed.In the future,we hope to carry out related research in other watersheds and also perform a more detailed studies to improve upon the results of this study.展开更多
While quality assessment is essential for testing, optimizing, benchmarking, monitoring, and inspecting related systems and services, it also plays an essential role in the design of virtually all visual signal proces...While quality assessment is essential for testing, optimizing, benchmarking, monitoring, and inspecting related systems and services, it also plays an essential role in the design of virtually all visual signal processing and communication algorithms, as well as various related decision-making processes. In this paper, we first provide an overview of recently derived quality assessment approaches for traditional visual signals (i.e., 2D images/videos), with highlights for new trends (such as machine learning approaches). On the other hand, with the ongoing development of devices and multimedia services, newly emerged visual signals (e.g., mobile/3D videos) are becoming more and more popular. This work focuses on recent progresses of quality metrics, which have been reviewed for the newly emerged forms of visual signals, which include scalable and mobile videos, High Dynamic Range (HDR) images, image segmentation results, 3D images/videos, and retargeted images.展开更多
The purpose of this experimental study is to evaluate the feasibility and oil recovery efficiency of continuous N_(2) injection in a multi-well fractured-cavity reservoir.In this study,the similar criterion of physica...The purpose of this experimental study is to evaluate the feasibility and oil recovery efficiency of continuous N_(2) injection in a multi-well fractured-cavity reservoir.In this study,the similar criterion of physical simulation was firstly discussed.In order to reveal the mechanism of remaining oil startup and production performance characteristic by continuous N_(2) injection,a visualized twodimensional fractured-cavity model and a three-dimensional pressure resistant model were designed and fabricated respectively based on the similar theory.And the 2D visualized physical experiments and 3D physical experiments were performed with the simulated oil and brine reservoir samples in Tahe oilfield.Four groups of experiments in 2D and 3D model were performed,each of which included bottom water depletion driving,water injection and N_(2) injection.The 2D visualized experiments indicated the main mechanism of N_(2) developing remaining oil was to occupy the high position and replace the attic oil due to gravitational differentiation.Furthermore,both the 2D and 3D experiments demonstrated that higher oil recovery factor could be achieved if N_(2) was injected through high positional wells.The 3D physical model is closer to the real reservoir condition,so the production performance can reflect the real field production process.This paper confirmed the efficiency of continuous N2 flooding in the light oil saturated fractured-cavity reservoir.展开更多
基金Supported by the Hohai University Scholarship Schemethe National Natural Science Foundation of China(Nos.41130639,51179045,41101017,412010208)the Innovation Program for Graduates in Jiangsu Province,China(No.CXZZ13_02)
文摘For sustainable water resource management,it is important to determine the relationship between streamfl ow and other variables that infl uence availability of water resources.However,many catchments do not have suffi cient data to allow for a more detailed study of these relationships.We faced a similar challenge in the Chengcun Basin(limited historical data: from 1986–1999); and therefore we used a new approach to overcome this.We found that,using nonparametric trend methods in conjunction with the climate elasticity analyses and the 2D visualization of hydrologic data,it is possible to assess the relationships between streamfl ow and other hydro-climatic variables.In the past,streamfl ow trends in the basin were more correlated with precipitation than with potential evapotranspiration(PET).In addition,there is a gradual shift in the hydrological regime of the catchment,which may affect the occurrence of available water resources and activities that depend on them.In addition,based on our climate sensitivity analyses,the streamfl ow is dependent and more sensitive to variations in precipitation than to PET(δQ=0.79δP+0.42δE; precipitation elasticity,ε P=1.32; PET elasticity,ε E=-2.10).Therefore pending more detailed studies,the use of our approach will provide a rapid means to assess the variation of water resources(streamfl ow)in a watershed.In the future,we hope to carry out related research in other watersheds and also perform a more detailed studies to improve upon the results of this study.
基金partially supported by the Research Grants Council of the Hong Kong SAR, China (Project CUHK 415712)the Ministry of Education Academic Research Fund (AcRF) Tier 2 in Singapore under Grant No. T208B1218
文摘While quality assessment is essential for testing, optimizing, benchmarking, monitoring, and inspecting related systems and services, it also plays an essential role in the design of virtually all visual signal processing and communication algorithms, as well as various related decision-making processes. In this paper, we first provide an overview of recently derived quality assessment approaches for traditional visual signals (i.e., 2D images/videos), with highlights for new trends (such as machine learning approaches). On the other hand, with the ongoing development of devices and multimedia services, newly emerged visual signals (e.g., mobile/3D videos) are becoming more and more popular. This work focuses on recent progresses of quality metrics, which have been reviewed for the newly emerged forms of visual signals, which include scalable and mobile videos, High Dynamic Range (HDR) images, image segmentation results, 3D images/videos, and retargeted images.
基金The authors wish to thank the National Natural Science Foundation of China(NO.51174216)State Key Science&Technology Project of China(NO.2011ZX05009-004 and NO.2011ZX05052)for their financial support to carry out this research.The insightful and constructive comments of the anonymous reviewers are also gratefully acknowledged.
文摘The purpose of this experimental study is to evaluate the feasibility and oil recovery efficiency of continuous N_(2) injection in a multi-well fractured-cavity reservoir.In this study,the similar criterion of physical simulation was firstly discussed.In order to reveal the mechanism of remaining oil startup and production performance characteristic by continuous N_(2) injection,a visualized twodimensional fractured-cavity model and a three-dimensional pressure resistant model were designed and fabricated respectively based on the similar theory.And the 2D visualized physical experiments and 3D physical experiments were performed with the simulated oil and brine reservoir samples in Tahe oilfield.Four groups of experiments in 2D and 3D model were performed,each of which included bottom water depletion driving,water injection and N_(2) injection.The 2D visualized experiments indicated the main mechanism of N_(2) developing remaining oil was to occupy the high position and replace the attic oil due to gravitational differentiation.Furthermore,both the 2D and 3D experiments demonstrated that higher oil recovery factor could be achieved if N_(2) was injected through high positional wells.The 3D physical model is closer to the real reservoir condition,so the production performance can reflect the real field production process.This paper confirmed the efficiency of continuous N2 flooding in the light oil saturated fractured-cavity reservoir.
