Resorting to cubic spline function instead of parametric spline representation, an explicit fairness indicator and an efficient fairing algorithm for 2D curves are presented. The input point sequence is firstly partit...Resorting to cubic spline function instead of parametric spline representation, an explicit fairness indicator and an efficient fairing algorithm for 2D curves are presented. The input point sequence is firstly partitioned into several overlapped function segments. For each segment, a cubic spline function is used as the representation tool which entails a polyline approximation of curvature plot. Based on the extrinsic relationship between the polyline and the positions of data points, a coarse-to-fine faring method is proposed which efficiently identifies and eliminates the unnecessary inflection points. Our algorithm generates the best results to date, which is validated by numerous practical examples.展开更多
Decoupling theory and application are introduced firstly, and then the status and prospect of decoupling relation between environmental pollution and economic growth are analyzed. Finally, choice criteria and connotat...Decoupling theory and application are introduced firstly, and then the status and prospect of decoupling relation between environmental pollution and economic growth are analyzed. Finally, choice criteria and connotation of decoupling indicators are studied.展开更多
Efficient detection of coalbed methane(CBM) co-production interference is the key to timely adjusting the development plan and improving the co-production efficiency. Based on production data of six typical CBM co-pro...Efficient detection of coalbed methane(CBM) co-production interference is the key to timely adjusting the development plan and improving the co-production efficiency. Based on production data of six typical CBM co-production wells in the Zhijin block of western Guizhou Province, China, the production characteristic curves, including production indication curve, curve of daily water production per unit drawdown of producing fluid level with time, and curve of water production per unit differential pressure with time have been analyzed to explore the response characteristics of co-production interference on the production characteristic curves. Based on the unit water inflow data of pumping test in coal measures, the critical value of in-situ water production of the CBM wells is 2 m^(3)/(d·m). The form and the slope of the initial linear section of the production indication curves have clear responses to the interference, which can be used to discriminate internal water source from external water source based on the critical slope value of 200 m^(3)/MPa in the initial linear section of the production indication curve. The time variation curves of water production per unit differential pressure can be divided into two morphological types: up-concave curve and down-concave curve. The former is represented by producing internal water with average daily gas production greater than 800 m^(3)/d, and the latter produces external water with average daily gas production smaller than 400 m^(3)/d. The method and critical indexes for recognition of CBM co-production interference based on the production characteristic curve are constructed. A template for discriminating interference of CBM co-production was constructed combined with the gas production efficiency analysis, which can provide reference for optimizing co-production engineering design and exploring economic and efficient co-production mode.展开更多
Global warming has attracted much concern about the worldwide organization, civil society groups, researchers, and so forth because the worldwide surface temperature has been expanding. This investigation intends to a...Global warming has attracted much concern about the worldwide organization, civil society groups, researchers, and so forth because the worldwide surface temperature has been expanding. This investigation intends to assess and compare the ability of a combination of land cover indices to predict the future distribution of land surface temperatures in Freetown using the Polynomial model analysis. Landsat satellite images of 1988, 1998, 2000, 2010, and 2018 of the Freetown Metropolitan zone were utilized for analysis. The investigation had adopted two land covers indices, Modification of normalized difference water index and Urban Index (UI) (e.g., MNDWI and UI) and applied a multi regression equation for forecasting the future LST. The stimulation results propose that the development will be accompanied by surface temperature increases, especially in Freetown’s western urban area. The temperature prevailing in the west of the metropolitan area may increase in the city somewhere in the range </span></span><span><span><span>from</span></span></span><span><span><span> 1988 to 2018. Additionally, the results of the LST prediction show that the model is perfect. Our discoveries can be represented as a helpful device for policymakers and community awareness by giving a scientific basis for sustainable urban planning and management.展开更多
Rule curves dictating target water levels for management have been implemented in several water bodies in North America over the last 70 years or more. Anthropogenic alterations of water levels are known to affect sev...Rule curves dictating target water levels for management have been implemented in several water bodies in North America over the last 70 years or more. Anthropogenic alterations of water levels are known to affect several components of wetland ecosystems. Evaluating the influence of rule curves on biological components with simple performance indicators could help harmonize water level management with wetland integrity. We assessed the potential of using the probability of common loon nest viability as a performance indicator of long-term impacts of rule curves on nesting wetland birds. We analyzed the outcome of rule curves on the probability of loon nest viability in Rainy Lake and Namakan Reservoir, 2 regulated water bodies located along the Ontario-Minnesota border. The analysis was focused on 4 hydrological time series between 1950 and 2013: 2 sets of time series simulating rule curves used to manage the water bodies in the past decades (referred to as the 1970RC and 2000RC), one of the historical measured water levels, and one of computed natural water levels. The probability of loon nest viability under the 1970RC was 2× higher than under natural conditions in both water bodies. The probability was also 2× higher under the 2000RC than under the 1970RC in the Namakan Reservoir but not in Rainy Lake. The rule curves generally improved conditions for nesting loons in both water bodies. The presented performance indicator can be used to evaluate future rule curves before they are implemented in the Rainy-Namakan or other similar systems.展开更多
目的探讨各项人体测量学指标在基层地区成人糖尿病筛查中的应用价值。方法这项横断面研究以2017年10月—2018年10月在新疆吉木萨尔县泉子街镇卫生院常规体检的成人作为研究对象,测量并计算腰围、身体质量指数(body mass index,BMI)、腰...目的探讨各项人体测量学指标在基层地区成人糖尿病筛查中的应用价值。方法这项横断面研究以2017年10月—2018年10月在新疆吉木萨尔县泉子街镇卫生院常规体检的成人作为研究对象,测量并计算腰围、身体质量指数(body mass index,BMI)、腰高比(waist-to-height ratio,WHtR)、A型形态指数(A body shape index,ABSI)、身体圆度指数(body roundness index,BRI)、锥削度指数(conicity index,CI)、BMI√腰围和WHt.5R等一系列人体测量学指标。采用Logistic回归模型和受试者工作特征曲线(receiver operating characteristic,ROC)对比分析各项人体测量学指标对于糖尿病筛查的应用价值。结果总共纳入4215例(男性1653例,女性2562例)研究对象,其中糖尿病患者为452例(占比10.2%)。Logistic回归模型显示,糖尿病患病风险增加与WHtR和BRI水平升高的相关性最强,而与ABSI的相关性最弱。ROC曲线分析显示,WHtR和BRI的AUC最大;WHtR的诊断切点分别为0.48(男)和0.49(女),BRI的诊断切点分别为3.02(男)和3.05(女)。结论各项人体测量学指标对基层地区成人糖尿病患病均有一定的预测价值,其中以WHtR和BRI的效能最高。展开更多
基金Supported by the National Natural Science Foundation of China(61222206,11526212)
文摘Resorting to cubic spline function instead of parametric spline representation, an explicit fairness indicator and an efficient fairing algorithm for 2D curves are presented. The input point sequence is firstly partitioned into several overlapped function segments. For each segment, a cubic spline function is used as the representation tool which entails a polyline approximation of curvature plot. Based on the extrinsic relationship between the polyline and the positions of data points, a coarse-to-fine faring method is proposed which efficiently identifies and eliminates the unnecessary inflection points. Our algorithm generates the best results to date, which is validated by numerous practical examples.
文摘Decoupling theory and application are introduced firstly, and then the status and prospect of decoupling relation between environmental pollution and economic growth are analyzed. Finally, choice criteria and connotation of decoupling indicators are studied.
基金National Natural Science Foundation of China(42002195)National Science and Technology Major Project(2016ZX05044)National Natural Science Foundation of China(42130802)。
文摘Efficient detection of coalbed methane(CBM) co-production interference is the key to timely adjusting the development plan and improving the co-production efficiency. Based on production data of six typical CBM co-production wells in the Zhijin block of western Guizhou Province, China, the production characteristic curves, including production indication curve, curve of daily water production per unit drawdown of producing fluid level with time, and curve of water production per unit differential pressure with time have been analyzed to explore the response characteristics of co-production interference on the production characteristic curves. Based on the unit water inflow data of pumping test in coal measures, the critical value of in-situ water production of the CBM wells is 2 m^(3)/(d·m). The form and the slope of the initial linear section of the production indication curves have clear responses to the interference, which can be used to discriminate internal water source from external water source based on the critical slope value of 200 m^(3)/MPa in the initial linear section of the production indication curve. The time variation curves of water production per unit differential pressure can be divided into two morphological types: up-concave curve and down-concave curve. The former is represented by producing internal water with average daily gas production greater than 800 m^(3)/d, and the latter produces external water with average daily gas production smaller than 400 m^(3)/d. The method and critical indexes for recognition of CBM co-production interference based on the production characteristic curve are constructed. A template for discriminating interference of CBM co-production was constructed combined with the gas production efficiency analysis, which can provide reference for optimizing co-production engineering design and exploring economic and efficient co-production mode.
文摘Global warming has attracted much concern about the worldwide organization, civil society groups, researchers, and so forth because the worldwide surface temperature has been expanding. This investigation intends to assess and compare the ability of a combination of land cover indices to predict the future distribution of land surface temperatures in Freetown using the Polynomial model analysis. Landsat satellite images of 1988, 1998, 2000, 2010, and 2018 of the Freetown Metropolitan zone were utilized for analysis. The investigation had adopted two land covers indices, Modification of normalized difference water index and Urban Index (UI) (e.g., MNDWI and UI) and applied a multi regression equation for forecasting the future LST. The stimulation results propose that the development will be accompanied by surface temperature increases, especially in Freetown’s western urban area. The temperature prevailing in the west of the metropolitan area may increase in the city somewhere in the range </span></span><span><span><span>from</span></span></span><span><span><span> 1988 to 2018. Additionally, the results of the LST prediction show that the model is perfect. Our discoveries can be represented as a helpful device for policymakers and community awareness by giving a scientific basis for sustainable urban planning and management.
文摘Rule curves dictating target water levels for management have been implemented in several water bodies in North America over the last 70 years or more. Anthropogenic alterations of water levels are known to affect several components of wetland ecosystems. Evaluating the influence of rule curves on biological components with simple performance indicators could help harmonize water level management with wetland integrity. We assessed the potential of using the probability of common loon nest viability as a performance indicator of long-term impacts of rule curves on nesting wetland birds. We analyzed the outcome of rule curves on the probability of loon nest viability in Rainy Lake and Namakan Reservoir, 2 regulated water bodies located along the Ontario-Minnesota border. The analysis was focused on 4 hydrological time series between 1950 and 2013: 2 sets of time series simulating rule curves used to manage the water bodies in the past decades (referred to as the 1970RC and 2000RC), one of the historical measured water levels, and one of computed natural water levels. The probability of loon nest viability under the 1970RC was 2× higher than under natural conditions in both water bodies. The probability was also 2× higher under the 2000RC than under the 1970RC in the Namakan Reservoir but not in Rainy Lake. The rule curves generally improved conditions for nesting loons in both water bodies. The presented performance indicator can be used to evaluate future rule curves before they are implemented in the Rainy-Namakan or other similar systems.
