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排序方式: 共有963条查询结果,搜索用时 15 毫秒
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陈军飞 《数学的实践与认识》2004,34(7):56-60
调水工程为解决区域间水资源分布不均衡问题提供了一种有效途径 .调水工程线路方案的优选问题涉及社会、经济、环境、技术等多方面的因素 ,是一个复杂的多目标决策问题 .本文建立了其评价指标体系 ,应用 AHP法和信息熵方法相结合确定评价指标权重 ,建立了调水工程线路方案优选的灰色系统评价模型 .算例显示方法的有效性 . 相似文献
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大学、企业研发与区域创新的空间统计与计量分析 总被引:18,自引:0,他引:18
利用空间统计的Moran指数和空间计量经济学的空间误差模型和空间滞后模型,对2000年中国大陆31个省域的创新产出与大学与企业的关系进行了空间计量经济分析。结果发现:31个省域创新能力贡献主要是由企业研究与开发投入实现,大学研发对区域创新能力没有明显的作用,大学与企业研发的结合也没有对区域创新产生明显贡献。 相似文献
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区域科技创新能力的灰色关联综合评价研究 总被引:9,自引:0,他引:9
采用灰色关联度确定权重的多目标决策方法,根据科技创新能力相关的数据指标集,对我国八大经济区科技创新能力给予了综合评价和排序.这种定量确定权重的方法,为综合评价区域的创新能力提供了一种更为实用、简洁、可操作性的新方法. 相似文献
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Effective routing of vehicles remains a focal goal of all modern enterprises, thriving for excellence in project management with minimal investment and operational costs. This paper proposes a metaheuristic methodology for solving a practical variant of the well-known Vehicle Routing Problem, called Heterogeneous Fixed Fleet VRP (HFFVRP). Using a two-phase construction heuristic, called GEneralized ROute Construction Algorithm (GEROCA), the proposed metaheuristic approach enhances its flexibility to easily adopt various operational constraints. Via this approach, two real-life distribution problems faced by a dairy and a construction company were tackled and formulated as HFFVRP. Computational results on the aforementioned case studies show that the proposed metaheuristic approach (a) consistently outperforms previous published metaheuristic approaches we have developed to solve the HFFVRP, and (b) substantially improves upon the current practice of the company. The key result that impressed both companies’ management was the improvement over the bi-objective character of their problems: the minimization of the total distribution cost as well as the minimization of the number of the given heterogeneous number of vehicles used. 相似文献
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Benjamin Bederson 《Physics in Perspective (PIP)》2005,7(4):453-472
I discuss the family background and early life of the German theoretical physicist Fritz Reiche (1883–1969) in Berlin; his
higher education at the University of Berlin under Max Planck (1858–1947); his subsequent work at the University of Breslau
with Otto Lummer (1860–1925); his return to Berlin in 1911, where he completed his Habilitation thesis in 1913, married Bertha
Ochs the following year, became a friend of Albert Einstein (1879–1955), and worked during and immediately after the Great
War. In 1921 he was appointed as ordentlicher Professor of Theoretical Physics at the University of Breslau and worked there until he was dismissed in 1933. He spent the academic
year 1934–1935 as a visiting professor at the German University in Prague and then returned to Berlin, where he remained until,
with the crucial help of his friend Rudolf Ladenburg (1882–1952) and vital assistance of the Emergency Committee in Aid of
Displaced Foreign Scholars, he, his wife Bertha, and their daughter Eve were able to emigrate to the United States in 1941
(their son Hans had already emigrated to England in 1939).From 1941–1946 he held appointments at the New School for Social
Research in New York, the City College of New York, and Union College in Schenectady, New York, and then was appointed as
an Adjunct Professor of Physics at New York University, where his contract was renewed year-by-year until his retirement in
1958. 相似文献