Ideal point method is one of the methods to solve multi-objective problem. It is applied to forest harvest regu-lation, and showed very good results by analyzing changes of quantitative indexes of forest resource stru...Ideal point method is one of the methods to solve multi-objective problem. It is applied to forest harvest regu-lation, and showed very good results by analyzing changes of quantitative indexes of forest resource structure before andafter the regulation. This method can be applied as one of the mathematical tools in forest harvest regulation.展开更多
Floods are essential for the regeneration and growth of floodplain forests in arid and semiarid regions. However, river flows, and especially flood flows, have decreased greatly with the increase of water diversion fr...Floods are essential for the regeneration and growth of floodplain forests in arid and semiarid regions. However, river flows, and especially flood flows, have decreased greatly with the increase of water diversion from rivers and/or reservoir regulation, resulting in severe deterioration of floodplain ecosystems. Estimation of the flood stage that will inundate the floodplain forest is necessary for the forest＇s restoration or protection. To balance water use for economic purposes and floodplain forest protection, the inundated forest width method is proposed for estimating the minimum flood stage for floodplain forests from the inundated forest width-stage curve. The minimum flood stage is defined as the breakpoint of the inundated forest width-stage curve, and is determined directly or analytically from the curve. For the analytical approach, the problem under consideration is described by a multi-objective optimization model, which can be solved by the ideal point method. Then, the flood flow at the minimum flood stage （minimum flood flow）, which is useful for flow regulation, can be calculated from the stage-discharge curve. In order to protect the forest in a river floodplain in a semiarid area in Xinjiang subject to reservoir regulation upstream, the proposed method was used to determine the minimum flood stage and flow for the forest. Field survey of hydrology, topography, and forest distribution was carried out at typical cross sections in the floodplain. Based on the survey results, minimum flood flows for six typical cross sections were estimated to be between 306 m3/s and 393 m3/s. Their maximum, 393 m3/s, was considered the minimum flood flow for the study river reach. This provides an appropriate flood flow for the protection of floodplain forest and can be used in the regulation of the upstream reservoir.展开更多
为测度环渤海港口高质量发展水平,选取2016—2020年12个港口相关数据,提出从创新、协调、绿色、开放、共享五个维度构建世界一流港口建设背景下环渤海港口高质量发展水平评价指标体系。运用CRITIC法确定各指标权重,通过逼近理想解排序法...为测度环渤海港口高质量发展水平,选取2016—2020年12个港口相关数据,提出从创新、协调、绿色、开放、共享五个维度构建世界一流港口建设背景下环渤海港口高质量发展水平评价指标体系。运用CRITIC法确定各指标权重,通过逼近理想解排序法(technique for order preference by similarity to ideal solution,TOPSIS)对其高质量发展水平进行测度;构建随机森林模型对其影响因素进行分析;使用修正的引力模型剖析环渤海港口高质量发展空间关联程度。结果表明:环渤海港口高质量发展水平整体呈上升趋势;按其发展水平可分为四个梯队,天津港和青岛港高质量发展综合指数明显高于其他港口;各个港口优势不同,存在明显差异;吞吐量、资源利用、进出口贸易等指标表现突出;环渤海港口空间关联强度不断提升,天津港、青岛港、大连港作为港口群的中心节点表现突出。展开更多
文摘Ideal point method is one of the methods to solve multi-objective problem. It is applied to forest harvest regu-lation, and showed very good results by analyzing changes of quantitative indexes of forest resource structure before andafter the regulation. This method can be applied as one of the mathematical tools in forest harvest regulation.
基金supported by the National Natural Science Foundation of China (Grant No.50879041)the New Century Excellent Talents in University (NCET) Program of the Ministry of Education of China (Grants No. 06-0059 and 07-0814)
文摘Floods are essential for the regeneration and growth of floodplain forests in arid and semiarid regions. However, river flows, and especially flood flows, have decreased greatly with the increase of water diversion from rivers and/or reservoir regulation, resulting in severe deterioration of floodplain ecosystems. Estimation of the flood stage that will inundate the floodplain forest is necessary for the forest＇s restoration or protection. To balance water use for economic purposes and floodplain forest protection, the inundated forest width method is proposed for estimating the minimum flood stage for floodplain forests from the inundated forest width-stage curve. The minimum flood stage is defined as the breakpoint of the inundated forest width-stage curve, and is determined directly or analytically from the curve. For the analytical approach, the problem under consideration is described by a multi-objective optimization model, which can be solved by the ideal point method. Then, the flood flow at the minimum flood stage （minimum flood flow）, which is useful for flow regulation, can be calculated from the stage-discharge curve. In order to protect the forest in a river floodplain in a semiarid area in Xinjiang subject to reservoir regulation upstream, the proposed method was used to determine the minimum flood stage and flow for the forest. Field survey of hydrology, topography, and forest distribution was carried out at typical cross sections in the floodplain. Based on the survey results, minimum flood flows for six typical cross sections were estimated to be between 306 m3/s and 393 m3/s. Their maximum, 393 m3/s, was considered the minimum flood flow for the study river reach. This provides an appropriate flood flow for the protection of floodplain forest and can be used in the regulation of the upstream reservoir.
文摘为测度环渤海港口高质量发展水平,选取2016—2020年12个港口相关数据,提出从创新、协调、绿色、开放、共享五个维度构建世界一流港口建设背景下环渤海港口高质量发展水平评价指标体系。运用CRITIC法确定各指标权重,通过逼近理想解排序法(technique for order preference by similarity to ideal solution,TOPSIS)对其高质量发展水平进行测度;构建随机森林模型对其影响因素进行分析;使用修正的引力模型剖析环渤海港口高质量发展空间关联程度。结果表明:环渤海港口高质量发展水平整体呈上升趋势;按其发展水平可分为四个梯队,天津港和青岛港高质量发展综合指数明显高于其他港口;各个港口优势不同,存在明显差异;吞吐量、资源利用、进出口贸易等指标表现突出;环渤海港口空间关联强度不断提升,天津港、青岛港、大连港作为港口群的中心节点表现突出。
