16 research outputs found
Southern Thailand: from conflict to negotiations?
Get PDFSummary: In this Analysis, University of Leeds professor Duncan McCargo argues that the recent Malaysian-backed Southern Thai peace initiative has now run into some serious problems. He argues that despite its various shortcomings the initiative is still worthy of support, since it has gained far more traction that any previous attempts to address the decade-long insurgency. Thailand needs to maintain focus on the southern conflict despite its current preoccupation with a national-level political crisis that threatens to topple the government of Yingluck Shinawatra.
Key findings
The conflict in Southern Thailand is one of Asia’s most serious insurgencies, with over 6,000 dead over the last 10 years.
The Malaysian government sponsored negotiations represents the best hope for reaching a political settlement and bringing peace to the region.
However, both sides need to show greater commitment to the negotiations, introducing new structures and procedures
Parametric Study of Nonlinear Adaptive Cruise Control for a Road Vehicle Model by MPC
Get PDFMPC (Model Predictive Control) techniques, with constraints, are applied to a nonlinear vehicle model
for the development of an ACC (Adaptive Cruise Control) system for transitional manoeuvres. The
dynamic model of the vehicle is developed in the continuous-time domain and captures the real dynamics
of the sub-vehicle models for steady-state and transient operations. A parametric study for the MPC
method is conducted to analyse the response of the ACC vehicle for critical manoeuvres. The simulation
results show the significant sensitivity of the response of the vehicle model with ACC to controller
parameter and comparisons are made with a previous study. Furthermore, the approach adopted in
this work is believed to reflect the control actions taken by a real vehicle
Analysis of an ACC System for Sliding Mode and MPC under Transitional Manoeuvers
No full textTwo different control algorithms, sliding mode and MPC (Model Predictive Control) are employed to
analyse the performance of a linear vehicle model equipped with an ACC (Adaptive Cruise Control)
system. Both controllers are analysed under critical TM (Transitional Maneuvers) to investigate their
suitability for the ACC system. The simulation results, for the same scenario, from both controllers\'
approach have been compared. The results show that the MPC is more robust than the SMC (Sliding
Model Controller). The results show that the SMC algorithm is not suitable for the proposed vehicle
model. The shortcomings of the SMC have been highlighted and the comparisons are made with the
previous studies. The proposed approach can be useful for the selection of the appropriate controller for
the given application
Analysis of the Controllers for the Transitional Manoeuvres of Adaptive Cruise Control Systems
Get PDFAnalysis of the Controllers for the Transitional Manoeuvres of Adaptive Cruise Control Systems
No full textPID (Proportional-Integral-Derivative) and MPC (Model Predictive Control) algorithms are used to
synthesize the upper-level controller of a vehicle equipped with an ACC (Adaptive Cruise Control)
system. Both controllers are analysed, with and without constraints, using a simple vehicle model under
critical TM (Transitional Manoeuvres). A comparative analysis of both controllers’ results has been
conducted. The comparison gives the suitability of MPC for ACC application over PID controller. The
flaws of PID control approach for the given application are highlighted. This approach can be helpful for
selecting the suitable controller for the given applicatio
Neural Network Course Changing and Track Keeping Controller for a Submarine
No full textThis paper presents the performance of ANN (Artificial Neural Networks) technique for the development
of controller for heading motions of submarine. A MLP (Multi-Layer Preceptron) FFNN (Feed-Forward
Neural Network) is used for development of controller. Supervised type of learning is used for training
of network by using back-propagation Algorithm. The training is performed by providing a nonlinear
sliding mode controller as a supervisor. The development of controller is based on nonlinear decoupled
heading model of a submarine without consideration of external environmental disturbances. To
demonstrate the robustness of controller the performance of controller is tested in different operating
conditions: course changing, track keeping and under the influence of sea currents. Simulations results
show that in all cases, the heading error comes to zero, which indicates that the actual heading converges
to the desired heading in finite time.
The maximum error is observed 0.5o for 45o command angle, in presence of sea currents. The result
demonstrates that the performance neural network controller has been robust
Fuzzy Logic Trajectory Tracking Controller for a Tanker
No full textThis paper proposes a fuzzy logic controller for design of autopilot of a ship. Triangular membership
functions have been use for fuzzification and the centroid method for defuzzification. A nonlinear
mathematical model of an oil tanker has been considered whose parameters vary with the depth of
water.
The performance of proposed controller has been tested under both course changing and trajectory
keeping mode of operations. It has been demonstrated that the performance is robust in shallow as well
as deep waters
Numerical Prediction of Closed Contra-Rotating Disc Flows
No full textThis paper provides the finite-difference solutions for closed contra-rotating discs flows at different disc
speed ratios for a fixed value of rotational Reynolds number of order five. The flow structure reveals that
when two discs rotate in opposite directions, the fluid mass outside the boundary layers is divided between
two regions, which give rise to the formation of two-cell flow structure. In order to assess the different
level of closures, two turbulence models low Reynolds number k-? model and low Reynolds number
second moment closure have been employed to predict the essential features of the closed contra-rotating
disc system. The most significant differences between the predictions of the two turbulence models occur
at the peak of slower disc boundary layer, because flow is more complex and turbulent on this side. The
comparison of predicted velocity profiles of two turbulence models show that the low Reynolds number
second moment closure produce a better agreement with measurements, particularly along the boundary
layers and in the central core region
