According to the measured data after impoundment and operation of the Three Gorges Reservoir,the reservoir sediment deposition and downstream river channel scouring are described briefly and compared with the research...According to the measured data after impoundment and operation of the Three Gorges Reservoir,the reservoir sediment deposition and downstream river channel scouring are described briefly and compared with the research results achieved in the demonstration stage.It is indicated through analysis that the reservoir sediment deposition and downstream river channel scouring during 8-year impoundment and operation are still within the original forecast,so the original forecasting results are feasible.The further observation and comparison should be conducted because the comparison between the observed data and the original forecast is not so sufficient in time and the prototype observation and related research work should be strengthened in the future.展开更多
This paper presents the possibilities of job optimization in waterway with multiple locks and canals, in order to increase the system productivity. Safe navigation in such complex waterway system is very demanding. So...This paper presents the possibilities of job optimization in waterway with multiple locks and canals, in order to increase the system productivity. Safe navigation in such complex waterway system is very demanding. Some of the problems that need to be solved are： How to control traffic in a way that vessels move in opposite directions; How to resolve possible conflicts in case that more vessels try to acquire particular lock at the same time; How to avoid possible deadlocks; How to ensure the vessel passage in the shortest possible time？ It is necessary to apply adequate control policy to avoid deadlocks and blocks the vessels＇ moving only in the case of dangerous situation. The motion of vessels can be described as the set of discrete events and states. Herein we propose deadlock avoidance algorithm for complex waterway system with multiple key resources and we use multiple re-entrant flowlines class of Petri net （MRF^PN）. The solution represents deadlock prevention supervisor in a sense that vessels are stopped only in a case of immediate dangerous situation in dense traffic. The goal of this paper is to find optimal, conflict and deadlock free job schedule in CWS. In this sense, the authors developed the algorithm which integrates MRF^PN with a genetic algorithm. The algorithm deals with multi-constrained scheduling problem with shared resources. The final goals are minimization the total travel time of vessels through the waterway system.展开更多
It is recognised that the blockage of culverts by woody debris can result in an increased risk of infrastructure damage and flooding.To date,debris transport analysis has focused on regional fluvial systems and large ...It is recognised that the blockage of culverts by woody debris can result in an increased risk of infrastructure damage and flooding.To date,debris transport analysis has focused on regional fluvial systems and large woody debris,both in flume and field experiments.Given the social and economic risk associated with urban flooding,and as urban drainage design shifts away from subsurface piped network reliance,there is an increasing need to understand debris movement in urban watercourses.The prediction of urban watercourse small woody debris(SWD)movement,both quantity and risk,has undergone only limited analysis predominantly due to lack of field data.This paper describes the development of a methodology to enable the collection of accurate and meaningful SWD residency and transportation data from watercourses.The presented research examines the limitations and effective function of PIT tag technology to collect SWD transport data in the field appropriate for risk and prediction analysis.Passive integrated transponder(PIT)technology provides a method to collect debris transport data within the urban environment.In this study,the tags are installed within small woody debris and released at known locations into a small urban natural watercourse enabling monitoring of movement and travel time.SWD velocity and detention are collated with solute time of travel,watercourse and point flow characteristics to identify the relationships between these key variables.The work presented tests three hypotheses:firstly,that the potential for unobstructed or un-detained SWD movement increases with flow velocity and water level.Secondly,that SWD travel distance,and the resistance forces along this travel path,influence SWD transport potential.Thirdly,the relationship between SWD and channel dimensions is examined with the aim of advancing representative debris transport prediction modelling.展开更多
基金support from the Technology Pillar Program during the"Eleventh Five-year Plan"Period (No.2006BAB05B02No.2006BAB05B03) are acknowledged
文摘According to the measured data after impoundment and operation of the Three Gorges Reservoir,the reservoir sediment deposition and downstream river channel scouring are described briefly and compared with the research results achieved in the demonstration stage.It is indicated through analysis that the reservoir sediment deposition and downstream river channel scouring during 8-year impoundment and operation are still within the original forecast,so the original forecasting results are feasible.The further observation and comparison should be conducted because the comparison between the observed data and the original forecast is not so sufficient in time and the prototype observation and related research work should be strengthened in the future.
文摘This paper presents the possibilities of job optimization in waterway with multiple locks and canals, in order to increase the system productivity. Safe navigation in such complex waterway system is very demanding. Some of the problems that need to be solved are： How to control traffic in a way that vessels move in opposite directions; How to resolve possible conflicts in case that more vessels try to acquire particular lock at the same time; How to avoid possible deadlocks; How to ensure the vessel passage in the shortest possible time？ It is necessary to apply adequate control policy to avoid deadlocks and blocks the vessels＇ moving only in the case of dangerous situation. The motion of vessels can be described as the set of discrete events and states. Herein we propose deadlock avoidance algorithm for complex waterway system with multiple key resources and we use multiple re-entrant flowlines class of Petri net （MRF^PN）. The solution represents deadlock prevention supervisor in a sense that vessels are stopped only in a case of immediate dangerous situation in dense traffic. The goal of this paper is to find optimal, conflict and deadlock free job schedule in CWS. In this sense, the authors developed the algorithm which integrates MRF^PN with a genetic algorithm. The algorithm deals with multi-constrained scheduling problem with shared resources. The final goals are minimization the total travel time of vessels through the waterway system.
基金supported by the Engineering and Physical Sciences Research Council(Grant Nos.EPSRC EP/J501335/1 and EP/K50337X/1)the Heriot-Watt University School of the Built Environment
文摘It is recognised that the blockage of culverts by woody debris can result in an increased risk of infrastructure damage and flooding.To date,debris transport analysis has focused on regional fluvial systems and large woody debris,both in flume and field experiments.Given the social and economic risk associated with urban flooding,and as urban drainage design shifts away from subsurface piped network reliance,there is an increasing need to understand debris movement in urban watercourses.The prediction of urban watercourse small woody debris(SWD)movement,both quantity and risk,has undergone only limited analysis predominantly due to lack of field data.This paper describes the development of a methodology to enable the collection of accurate and meaningful SWD residency and transportation data from watercourses.The presented research examines the limitations and effective function of PIT tag technology to collect SWD transport data in the field appropriate for risk and prediction analysis.Passive integrated transponder(PIT)technology provides a method to collect debris transport data within the urban environment.In this study,the tags are installed within small woody debris and released at known locations into a small urban natural watercourse enabling monitoring of movement and travel time.SWD velocity and detention are collated with solute time of travel,watercourse and point flow characteristics to identify the relationships between these key variables.The work presented tests three hypotheses:firstly,that the potential for unobstructed or un-detained SWD movement increases with flow velocity and water level.Secondly,that SWD travel distance,and the resistance forces along this travel path,influence SWD transport potential.Thirdly,the relationship between SWD and channel dimensions is examined with the aim of advancing representative debris transport prediction modelling.
