In order to understand how the uncertainties in the output can be apportioned to different sources of uncertainties in its inputs, it is critical to investigate the sensitivity of MOVES model. The MOVES model sensitiv...In order to understand how the uncertainties in the output can be apportioned to different sources of uncertainties in its inputs, it is critical to investigate the sensitivity of MOVES model. The MOVES model sensitivity for regional level has been well studied. However, the uncertainty analysis for project level running emissions has not been well understood. In this research, the MOVES model project level sensitivity tests on running emissions were conducted thru the analysis of vehicle specific power （VSP）, scaled tractive power （STP）, and MOVES emission rates versus speed curves. This study tested the speed, acceleration, and grade-three most critical variables for vehicle specific power for light duty vehicles and scaled tractive power for heavy duty vehicles. For the testing of STP, four regulatory classes of heavy duty vehicles including light heavy duty （LHD）, medium heavy duty （MHD）, heavy heavy duty （HHD） and bus were selected. MOVES project running emission rates were also tested for CO, PM2.5, NOx, and VOC versus the operating speeds. A Latin Hypercube （LH） sampling based on method for estimation of the ＂Sobal＂ sensitivity indices shows that the speed is the most critical variable among the three inputs for both VSP and STP. Acceleration and grades show lower response to the main effects and sensitivity indices. MOVES emission rates versus speeds curves for light duty vehicles show that highest emission occurs at lower speed range. No significant differences on emission rates among the regulatory classes of heavy duty vehicles are identified.展开更多
Grand infrastructure projects,such as dam,power plant,petroleum,and gas industry projects,have several contractors working on them in several independent sub-projects.The concern of reducing the duration of these proj...Grand infrastructure projects,such as dam,power plant,petroleum,and gas industry projects,have several contractors working on them in several independent sub-projects.The concern of reducing the duration of these projects is one of the important issues among various aspects;thus,our aim is to fulfill the requirements by using the game theory approach.In this study,a mixed-integer programming model consisting of game theory and project scheduling is developed to reduce the duration of projects with a minimum increase in costs.In this model,two contractors in successive periods are entered into a step-by-step competition by the employer during dynamic games,considering an exchange in their limited resources.The optimum solution of the game in each stage are selected as the strategy,and the resources during the game are considered to be renewable and limited.The strategy of each contractor can be described as follows:1)share their resources with the other contractor and 2)not share the resources with the other contractor.This model can act dynamically in all circumstances during project implementation.If a player chooses a non-optimum strategy,then this strategy can immediately update itself at the succeeding time period.The proposed model is solved using the exact Benders decomposition method,which is coded in GAMS software.The results suggest the implementation of four step-by-step games between the contractors.Then,the results of our model are compared with those of the conventional models.The projects’duration in our model is reduced by 22.2%.The nominal revenue of both contractors has also reached a significant value of 46078 units compared with the relative value of zero units in the original model.Moreover,we observed in both projects the decreases of 19.5%,20.9%,and 19.7%in the total stagnation of resources of types 1,2,and 3,respectively.展开更多
基金support by U.S.Environmental Protection AgencyOhio Department of Transportation
文摘In order to understand how the uncertainties in the output can be apportioned to different sources of uncertainties in its inputs, it is critical to investigate the sensitivity of MOVES model. The MOVES model sensitivity for regional level has been well studied. However, the uncertainty analysis for project level running emissions has not been well understood. In this research, the MOVES model project level sensitivity tests on running emissions were conducted thru the analysis of vehicle specific power （VSP）, scaled tractive power （STP）, and MOVES emission rates versus speed curves. This study tested the speed, acceleration, and grade-three most critical variables for vehicle specific power for light duty vehicles and scaled tractive power for heavy duty vehicles. For the testing of STP, four regulatory classes of heavy duty vehicles including light heavy duty （LHD）, medium heavy duty （MHD）, heavy heavy duty （HHD） and bus were selected. MOVES project running emission rates were also tested for CO, PM2.5, NOx, and VOC versus the operating speeds. A Latin Hypercube （LH） sampling based on method for estimation of the ＂Sobal＂ sensitivity indices shows that the speed is the most critical variable among the three inputs for both VSP and STP. Acceleration and grades show lower response to the main effects and sensitivity indices. MOVES emission rates versus speeds curves for light duty vehicles show that highest emission occurs at lower speed range. No significant differences on emission rates among the regulatory classes of heavy duty vehicles are identified.
文摘Grand infrastructure projects,such as dam,power plant,petroleum,and gas industry projects,have several contractors working on them in several independent sub-projects.The concern of reducing the duration of these projects is one of the important issues among various aspects;thus,our aim is to fulfill the requirements by using the game theory approach.In this study,a mixed-integer programming model consisting of game theory and project scheduling is developed to reduce the duration of projects with a minimum increase in costs.In this model,two contractors in successive periods are entered into a step-by-step competition by the employer during dynamic games,considering an exchange in their limited resources.The optimum solution of the game in each stage are selected as the strategy,and the resources during the game are considered to be renewable and limited.The strategy of each contractor can be described as follows:1)share their resources with the other contractor and 2)not share the resources with the other contractor.This model can act dynamically in all circumstances during project implementation.If a player chooses a non-optimum strategy,then this strategy can immediately update itself at the succeeding time period.The proposed model is solved using the exact Benders decomposition method,which is coded in GAMS software.The results suggest the implementation of four step-by-step games between the contractors.Then,the results of our model are compared with those of the conventional models.The projects’duration in our model is reduced by 22.2%.The nominal revenue of both contractors has also reached a significant value of 46078 units compared with the relative value of zero units in the original model.Moreover,we observed in both projects the decreases of 19.5%,20.9%,and 19.7%in the total stagnation of resources of types 1,2,and 3,respectively.
