The paper studies the non-zero slacks in data envelopment analysis. A procedure is developed for the treatment of non-zero slacks. DEA projections can be done just in one step.
Slacking experiments were performed on the red beds weak rock from vicinity of Changsha. Grain size distribution of the slacking rock was tested periodically during the experiments, which can be used to describe the p...Slacking experiments were performed on the red beds weak rock from vicinity of Changsha. Grain size distribution of the slacking rock was tested periodically during the experiments, which can be used to describe the physical transition of red beds weak rock during slacking process. According to the similar characters of many attributions such as environmental moisture, mineralogical composition, grain size and other factors between big rocks before slacking and its slacked product, the self-similar property of big rock and the small one can be induced. Fractal concept was introduced to construct the slacking model of red beds weak rock. Combining the supposed relationship of time for slacking and grain size of weak rock, the mathematic simulation of slacking process of red beds weak rock was conducted. To simplify the parameters back calculation, the fractal model proposed by Tyler and Wheatcraft was introduced to describe the characters of grain size distribution variation. The results show that the fractal dimension calculated from simulation data meet experiments data closely, which proves that the mathematic simulation method is reasonable and the parameters determination method is effective.展开更多
为捋清沿黄九省(区)水资源利用效率(water resource utilization efficiency,WRUE)的现状,明晰水资源利用效率的影响因素,助力该地区水资源的高效利用,基于全局超效率模型(global super efficiency slack based model,SBM)、层次分析法(...为捋清沿黄九省(区)水资源利用效率(water resource utilization efficiency,WRUE)的现状,明晰水资源利用效率的影响因素,助力该地区水资源的高效利用,基于全局超效率模型(global super efficiency slack based model,SBM)、层次分析法(analytical hierarchy process,AHP)和Tobit模型,从农业、工业、生活、生态和综合5个方面对水资源利用效率的变化情况和影响因素进行分析,结果表明:沿黄九省(区)农业、工业、生活、生态和综合水资源利用效率在2003−2022年的均值分别为0.417、0.511、0.635、0.465和0.506,总体均呈上升趋势。黄河中下游省(区)的农业、工业、生活和综合水资源利用效率高于上游省(区),黄河上游省(区)的生态水资源利用效率略高于中下游省(区)。人均GDP、第三产业产值占比、R&D经费投入强度与综合水资源利用效率呈正相关,人均水资源量、人口城镇化率、农业工业用水占比与其呈负相关。对沿黄九省(区)提出如下发展建议:优化产业结构和用水结构;加强水资源禀赋较好地区和城镇化水平较高地区的节水管控;沿黄西部省(区)加强与节水相关的科技创新。展开更多
文摘The paper studies the non-zero slacks in data envelopment analysis. A procedure is developed for the treatment of non-zero slacks. DEA projections can be done just in one step.
基金Project (95-05-01-45) supported by the Ministry of Communications of China
文摘Slacking experiments were performed on the red beds weak rock from vicinity of Changsha. Grain size distribution of the slacking rock was tested periodically during the experiments, which can be used to describe the physical transition of red beds weak rock during slacking process. According to the similar characters of many attributions such as environmental moisture, mineralogical composition, grain size and other factors between big rocks before slacking and its slacked product, the self-similar property of big rock and the small one can be induced. Fractal concept was introduced to construct the slacking model of red beds weak rock. Combining the supposed relationship of time for slacking and grain size of weak rock, the mathematic simulation of slacking process of red beds weak rock was conducted. To simplify the parameters back calculation, the fractal model proposed by Tyler and Wheatcraft was introduced to describe the characters of grain size distribution variation. The results show that the fractal dimension calculated from simulation data meet experiments data closely, which proves that the mathematic simulation method is reasonable and the parameters determination method is effective.
