Browsing by Author "Wang, Qunwei"

Now showing 1 - 4 of 4

An alternative metafrontier framework for measuring the heterogeneity of technology
(2018-08-01)
Wang, Qunwei
;
Hang, Ye
;
Hu, Jin-Li
;
Chiu, Ching-Ren
;
經營管理研究所
The metafrontier framework proposed by O'Donnell et al. enables the evaluation of relative efficiencies for decision-making units (DMUs) operating under heterogeneous technologies. The metatechnology ratio (MTR) constructed under the metafrontier framework helps estimate the gap between group frontiers and the metafrontier, with its score between 0 and 1. However, an unreasonable MTR value (ie, greater than 1) may appear when the traditional metafrontier framework is applied in the nonradial data envelopment analysis (DEA) models. This article proposes an alternative metafrontier framework for addressing this issue. The newly constructed technology gap measurement (TGM) can avoid unreasonable technology gap ratio values in nonradial DEA models and substitute for MTR in radial DEA models. To demonstrate how this alternative metafrontier approach works, this article applies it to the efficiency evaluation of regional transportation sectors in China.
Integrated airline productivity performance evaluation with CO2 emissions and flight delays
(2020-05-01)
Huang, Fei
;
Zhou, Dequn
;
Hu, Jin-Li
;
Wang, Qunwei
;
經營管理研究所
This paper evaluates the airline productivity change by applying a modified global Malmquist productivity index (GMPI) model, incorporating both CO2 emissions and flight delays. Statistical inference is also performed on the GMPI results using the bootstrapping method. Empirical research was conducted on 15 international airlines during 2011-2017. The obtained results showed that the productivity of all airlines had been fluctuating and experienced a slight increase over 2011-2017. Most of these 15 airlines made more progress in managing punctuality than CO2 emissions. High punctuality policy may not be the best choice for all airlines when considering financial constraints, while airlines in more liberalized aviation markets are more likely to improve productivity by reducing flight delays. Efficiency change and technological change were the major driving factors for the growth of airline productivity. European and US airlines benefitted more from superior technology, while most Asian and Oceanian airlines still benefitted from the advantage of efficiency. Based on the findings, specific management advice was given.
Minimizing the Carbon Footprint for the Time-Dependent Heterogeneous-Fleet Vehicle Routing Problem with Alternative Paths
(2014-07-01)
Liu, Wan-Yu
;
Lin, Chun-Cheng
;
Chiu, Ching-Ren
;
Tsao, You-Song
;
Wang, Qunwei
Torespondto the reduction of greenhouse gas emissions and global warming, this paper investigates the minimal-carbon-footprint time-dependent heterogeneous-fleet vehicle routing problem with alternative paths (MTHVRPP). This finds a route with the smallestcarbon footprint, instead of the shortestroute distance, which is the conventional approach, to serve a number of customers with a heterogeneous fleet of vehicles in cases wherethere may not be only one path between each pair of customers, and the vehicle speed differs at different times of the day. Inheriting from the NP-hardness of the vehicle routing problem, the MTHVRPP is also NP-hard. This paper further proposes a genetic algorithm (GA) to solve this problem. The solution representedbyour GA determines the customer serving ordering of each vehicle type. Then, the capacity check is used to classify multiple routes of each vehicle type, and the path selection determines the detailed paths of each route. Additionally, this paper improves the energy consumption model used for calculating the carbon footprint amount more precisely. Compared with the results without alternative paths, our experimental results show that the alternative path in this experimenthas a significant impact on the experimental results in terms of carbon footprint.
Minimizing the Carbon Footprint for the Time-Dependent Heterogeneous-Fleet Vehicle Routing Problem with Alternative Paths
(2014-07-01)
Liu, Wan-Yu
;
Lin, Chun-Cheng
;
Chiu, Ching-Ren
;
Tsao, You-Song
;
Wang, Qunwei
Torespondto the reduction of greenhouse gas emissions and global warming, this paper investigates the minimal-carbon-footprint time-dependent heterogeneous-fleet vehicle routing problem with alternative paths (MTHVRPP). This finds a route with the smallestcarbon footprint, instead of the shortestroute distance, which is the conventional approach, to serve a number of customers with a heterogeneous fleet of vehicles in cases wherethere may not be only one path between each pair of customers, and the vehicle speed differs at different times of the day. Inheriting from the NP-hardness of the vehicle routing problem, the MTHVRPP is also NP-hard. This paper further proposes a genetic algorithm (GA) to solve this problem. The solution representedbyour GA determines the customer serving ordering of each vehicle type. Then, the capacity check is used to classify multiple routes of each vehicle type, and the path selection determines the detailed paths of each route. Additionally, this paper improves the energy consumption model used for calculating the carbon footprint amount more precisely. Compared with the results without alternative paths, our experimental results show that the alternative path in this experimenthas a significant impact on the experimental results in terms of carbon footprint.