Coordinating on-ramp queue control with adjacent local signal controller: an algorithm to assist ramp metering application
This paper describes a queue control algorithm which is able to coordinate its operation with that of an adjacent local signal control so that its efficiency is improved. A microscopic simulation model (AIMSUN) was used to test the operation of the new queue control algorithm and compare its performance with that of the standard queue control. The assessment has shown the new algorithm to be a significant improvement in reducing the variation of the release rate and the frequency of exceeding the storage capacity whilst the efficiency of utilising ramp space increased. Also, the new algorithm was found to be less sensitive to changes in ramp demand and some parameter settings originally found critical to the operation of standard queue control. For the covering abstract see ITRD E134653.
SERIES OF NEW LOCAL RAMP METERING STRATEGIES
The local ramp metering strategy ALINEA is the only available feedback strategy that is based on powerful and robust automatic control methods. A number of modifications and extensions were proposed to address specific issues and needs not covered by ALINEA. More specifically, the following new local ramp metering strategies are presented: FL-ALINEA is a flow-based strategy, UP-ALINEA is an upstream-occupancy-based version, and UF-ALINEA is an upstream-flow-based strategy. X-ALINEA/Q is a combination of any of the preceding strategies with efficient ramp-queue control to avoid interference with surface street traffic. The new local ramp metering strategies are discussed with respect to their features, their limitations, and their relation to available strategies. Macroscopic simulation investigations demonstrate the capabilities and limitations of the new strategies.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.