The efficiency of yard operations is critical to the overall productivity of a container terminal because the yard serves as the interface between the landside and waterside operations.Most container terminals use yar...The efficiency of yard operations is critical to the overall productivity of a container terminal because the yard serves as the interface between the landside and waterside operations.Most container terminals use yard cranes to transfer containers between the yard and trucks(both external and internal).To facilitate vessel operations,an efficient work schedule for the yard cranes is necessary given varying work volumes among yard blocks with different planning periods.This paper investigated an agent-based approach to assign and relocate yard cranes among yard blocks based on the forecasted work volumes.The goal of our study is to reduce the work volume that remains incomplete at the end of a planning period.We offered several preference functions for yard cranes and blocks which are modeled as agents.These preference functions are designed to find effective schedules for yard cranes.In addition,we examined various rules for the initial assignment of yard cranes to blocks.Our analysis demonstrated that our model can effectively and efficiently reduce the percentage of incomplete work volume for any real-world sized problem.展开更多
A key strategy for successful access management is the adoption of driveway spacing guidelines that consider both safety and operations.The goal is to provide sufficient distance from one driveway to the next so that ...A key strategy for successful access management is the adoption of driveway spacing guidelines that consider both safety and operations.The goal is to provide sufficient distance from one driveway to the next so that drivers can perceive and react to the conditions at each potential conflict point in succession.State DOTs across the country have adopted different driveway spacing standards that vary according to the access class and characteristics of the adjacent roadway,such as type of roadway,posted speed limit,and traffic volume.Utilizing the VISSIM microscopic traffic simulation tool and FHWA’s Surrogate Safety Assessment Model(SSAM),this research examined safety implications of four different driveway spacing policies representing 13 states.The analysis involved calibrating the VISSIM model for an arterial roadway corridor in West Columbia,SC,and then using the calibrated model to simulate various operational changes to the corridor,including speed limits,traffic volumes,and the associated minimum driveway spacing criteria for the four different policies.SSAM was used to analyze vehicle trajectories derived from VISSIM to determine the number of conflict points.Experimental results indicate that posted speed limit and traffic volume are the primary impact factors for driveway safety,and thus,these parameters should be considered in establishing minimum driveway spacing.Findings from this study indicate that there are significant differences in safety impacts between the different driveway spacing policies adopted by various state DOTs.展开更多
文摘The efficiency of yard operations is critical to the overall productivity of a container terminal because the yard serves as the interface between the landside and waterside operations.Most container terminals use yard cranes to transfer containers between the yard and trucks(both external and internal).To facilitate vessel operations,an efficient work schedule for the yard cranes is necessary given varying work volumes among yard blocks with different planning periods.This paper investigated an agent-based approach to assign and relocate yard cranes among yard blocks based on the forecasted work volumes.The goal of our study is to reduce the work volume that remains incomplete at the end of a planning period.We offered several preference functions for yard cranes and blocks which are modeled as agents.These preference functions are designed to find effective schedules for yard cranes.In addition,we examined various rules for the initial assignment of yard cranes to blocks.Our analysis demonstrated that our model can effectively and efficiently reduce the percentage of incomplete work volume for any real-world sized problem.
文摘A key strategy for successful access management is the adoption of driveway spacing guidelines that consider both safety and operations.The goal is to provide sufficient distance from one driveway to the next so that drivers can perceive and react to the conditions at each potential conflict point in succession.State DOTs across the country have adopted different driveway spacing standards that vary according to the access class and characteristics of the adjacent roadway,such as type of roadway,posted speed limit,and traffic volume.Utilizing the VISSIM microscopic traffic simulation tool and FHWA’s Surrogate Safety Assessment Model(SSAM),this research examined safety implications of four different driveway spacing policies representing 13 states.The analysis involved calibrating the VISSIM model for an arterial roadway corridor in West Columbia,SC,and then using the calibrated model to simulate various operational changes to the corridor,including speed limits,traffic volumes,and the associated minimum driveway spacing criteria for the four different policies.SSAM was used to analyze vehicle trajectories derived from VISSIM to determine the number of conflict points.Experimental results indicate that posted speed limit and traffic volume are the primary impact factors for driveway safety,and thus,these parameters should be considered in establishing minimum driveway spacing.Findings from this study indicate that there are significant differences in safety impacts between the different driveway spacing policies adopted by various state DOTs.
