Data envelopment analysis （DEA） is an effective non-parametric method for measuring the relative efficiencies of decision making units （DMUs） with multiple inputs and outputs. In many real situations, the internal...Data envelopment analysis （DEA） is an effective non-parametric method for measuring the relative efficiencies of decision making units （DMUs） with multiple inputs and outputs. In many real situations, the internal structure of DMUs is a two-stage network process with shared inputs used in both stages and common outputs produced by the both stages. For example, hospitals have a two-stage network structure. Stage 1 consumes resources such as information technology system, plant, equipment and admin personnel to generate outputs such as medical records, laundry and housekeeping. Stage 2 consumes the same set of resources used by stage 1 （named shared inputs） and the outputs generated by stage 1 （named intermediate measures） to provide patient services. Besides, some of outputs, for instance, patient satisfaction degrees, are generated by the two individual stages together （named shared outputs）. Since some of shared inputs and outputs are hard split up and allocated to each individual stage, it needs to develop two-stage DEA methods for evaluating the performance of two-stage network processes in such problems. This paper extends the centralized model to measure the DEA efficiency of the two-stage process with non split-table shared inputs and outputs. A weighted additive approach is used to combine the two individual stages. Moreover, additive efficiency decomposition models are developed to simultaneously evaluate the maximal and the minimal achievable efficiencies for the individual stages. Finally, an example of 17 city branches of China Construction Bank in Anhui Province is employed to illustrate the proposed approach.展开更多
输入串联输出并联型(input-series output-parallel,ISOP)直流变换器广泛应用于能源互联网中的直流电网场景,其关键问题在于解决系统模块间输入电压不均衡。为此,结合谐振型和移相型双有源桥(dual active bridge,DAB)变换器,提出一种具...输入串联输出并联型(input-series output-parallel,ISOP)直流变换器广泛应用于能源互联网中的直流电网场景,其关键问题在于解决系统模块间输入电压不均衡。为此,结合谐振型和移相型双有源桥(dual active bridge,DAB)变换器,提出一种具备自适应均压能力的混合型模块化ISOP型直流变换器,系统同时具备谐振型DAB的高效率和移相型DAB的灵活控制能力。通过在DAB源端的滞后桥臂中点增设无源的LC谐振支路,该谐振支路与相邻子模块的2个半桥模块共同构成非隔离型双有源半桥,以此来实现系统输入电压的自适应均衡。此外,提出一种低电压穿越(low voltage ride-through,LVRT)方法,在DAB前端连接电压调整模块,模块内部的高频变压器的副边串联电感,当系统输入输出侧发生电压跌落时具备故障穿越的能力,提高系统的暂态可控性。最后,在MATLAB/SIMULINK环境下搭建模型进行验证,可以证明系统的自适应均压性能及故障穿越方法的有效性。展开更多
基金Acknowledgments The authors thank the editors and two anonymous referees for their helpful comments and suggestions that substantially improved the quality of this work. This research has been supported by grants from National Natural Science Foundation of China （71224001） and China Postdoctoral Science Foundation funded project （2015M571135）.
文摘Data envelopment analysis （DEA） is an effective non-parametric method for measuring the relative efficiencies of decision making units （DMUs） with multiple inputs and outputs. In many real situations, the internal structure of DMUs is a two-stage network process with shared inputs used in both stages and common outputs produced by the both stages. For example, hospitals have a two-stage network structure. Stage 1 consumes resources such as information technology system, plant, equipment and admin personnel to generate outputs such as medical records, laundry and housekeeping. Stage 2 consumes the same set of resources used by stage 1 （named shared inputs） and the outputs generated by stage 1 （named intermediate measures） to provide patient services. Besides, some of outputs, for instance, patient satisfaction degrees, are generated by the two individual stages together （named shared outputs）. Since some of shared inputs and outputs are hard split up and allocated to each individual stage, it needs to develop two-stage DEA methods for evaluating the performance of two-stage network processes in such problems. This paper extends the centralized model to measure the DEA efficiency of the two-stage process with non split-table shared inputs and outputs. A weighted additive approach is used to combine the two individual stages. Moreover, additive efficiency decomposition models are developed to simultaneously evaluate the maximal and the minimal achievable efficiencies for the individual stages. Finally, an example of 17 city branches of China Construction Bank in Anhui Province is employed to illustrate the proposed approach.
文摘输入串联输出并联型(input-series output-parallel,ISOP)直流变换器广泛应用于能源互联网中的直流电网场景,其关键问题在于解决系统模块间输入电压不均衡。为此,结合谐振型和移相型双有源桥(dual active bridge,DAB)变换器,提出一种具备自适应均压能力的混合型模块化ISOP型直流变换器,系统同时具备谐振型DAB的高效率和移相型DAB的灵活控制能力。通过在DAB源端的滞后桥臂中点增设无源的LC谐振支路,该谐振支路与相邻子模块的2个半桥模块共同构成非隔离型双有源半桥,以此来实现系统输入电压的自适应均衡。此外,提出一种低电压穿越(low voltage ride-through,LVRT)方法,在DAB前端连接电压调整模块,模块内部的高频变压器的副边串联电感,当系统输入输出侧发生电压跌落时具备故障穿越的能力,提高系统的暂态可控性。最后,在MATLAB/SIMULINK环境下搭建模型进行验证,可以证明系统的自适应均压性能及故障穿越方法的有效性。
