8,688 research outputs found
Back-pressure traffic signal control with unknown routing rates
The control of a network of signalized intersections is considered. Previous
works proposed a feedback control belonging to the family of the so-called
back-pressure controls that ensures provably maximum stability given
pre-specified routing probabilities. However, this optimal back-pressure
controller (BP*) requires routing rates and a measure of the number of vehicles
queuing at a node for each possible routing decision. It is an idealistic
assumption for our application since vehicles (going straight, turning
left/right) are all gathered in the same lane apart from the proximity of the
intersection and cameras can only give estimations of the aggregated queue
length. In this paper, we present a back-pressure traffic signal controller
(BP) that does not require routing rates, it requires only aggregated queue
lengths estimation (without direction information) and loop detectors at the
stop line for each possible direction. A theoretical result on the Lyapunov
drift in heavy load conditions under BP control is provided and tends to
indicate that BP should have good stability properties. Simulations confirm
this and show that BP stabilizes the queuing network in a significant part of
the capacity region.Comment: accepted for presentation at IFAC 2014, 6 pages. arXiv admin note:
text overlap with arXiv:1309.648
The use of simulation in the design of a road transport incident detection algorithm
Automatic incident detection is becoming one of the core tools of urban traffic management, enabling more rapid identification and response to traffic incidents and congestion. Existing traffic detection infrastructure within urban areas (often installed for traffic signal optimization) provides urban traffic control systems with a near continuous stream of data on the state of traffic within the network. The creation of a simulation to replicate such a data stream therefore provides a facility for the development of accurate congestion detection and warning algorithms. This paper describes firstly the augmentation of a commercial traffic model to provide an urban traffic control simulation platform and secondly the development of a new incident detection system (RAID-Remote Automatic Incident Detection), with the facility to use the simulation platform as an integral part of the design and calibration process. A brief description of a practical implementation of RAID is included along with summary evaluation results
Handover Management in Highly Dense Femtocellular Networks
For dense femtocells, intelligent integrated femtocell/macrocell network
architecture, a neighbor cell list with a minimum number of femtocells,
effective call admission control (CAC), and handover processes with proper
signaling are the open research issues. An appropriate traffic model for the
integrated femtocell/macrocell network is also not yet developed. In this
paper, we present the major issue of mobility management for the integrated
femtocell/macrocell network. We propose a novel algorithm to create a neighbor
cell list with a minimum, but appropriate, number of cells for handover. We
also propose detailed handover procedures and a novel traffic model for the
integrated femtocell/macrocell network. The proposed CAC effectively handles
various calls. The numerical and simulation results show the importance of the
integrated femtocell/macrocell network and the performance improvement of the
proposed schemes. Our proposed schemes for dense femtocells will be very
effective for those in research and industry to implement
Networked PID control design : a pseudo-probabilistic robust approach
Networked Control Systems (NCS) are feedback/feed-forward control systems where control components (sensors, actuators and controllers) are distributed across a common communication network. In NCS, there exist network-induced random delays in each channel. This paper proposes a method to compensate the effects of these delays for the design and tuning of PID controllers. The control design is formulated as a constrained optimization problem and the controller stability and robustness criteria are incorporated as design constraints. The design is based on a polytopic description of the system using a Poisson pdf distribution of the delay. Simulation results are presented to demonstrate the performance of the proposed method
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