In the present article, the origin-destination (O-D) trip matrix estimation is formulated as a simultaneous optimization problem and is resolved by employing three different meta-heuristic optimization algorithms. The...
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In the present article, the origin-destination (O-D) trip matrix estimation is formulated as a simultaneous optimization problem and is resolved by employing three different meta-heuristic optimization algorithms. These include a genetic algorithm (GA), a simulated annealing (SA) algorithm, and a hybrid algorithm (GASA) based on the combination of GA and SA. The computational performance of the three algorithms is evaluated and compared by implementing them on a realistic urban road network. The results of the simulation tests demonstrate that SA and GASA produce a more accurate final solution than GA, whereas GASA shows a superior convergence rate, that is, faster improvement from the initial solution, in comparison to SA and GA. In addition, GASA produces a final solution that is more robust and less dependent on the initial demand pattern, in comparison to that obtained from a greedy search algorithm.
The authors propose a coordinate rotation digital computer (CORDIC) rotator algorithm that eliminates the problems of scale factor compensation and limited range of convergence associated with the classical CORDIC alg...
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The authors propose a coordinate rotation digital computer (CORDIC) rotator algorithm that eliminates the problems of scale factor compensation and limited range of convergence associated with the classical CORDIC algorithm. In the proposed scheme, depending on the target angle or the initial coordinate of the vector, a scaling by 1 or 1/root2 is needed that can be realised with minimal hardware. The proposed CORDIC rotator adaptively selects the appropriate iteration steps and converges to the final result by executing on average only 50% of the number of iterations required by the classical CORDIC. Unlike for the classical CORDIC, the value of the scale factor is completely independent of the number of executed iterations. Based on the proposed algorithm, a 16-bit pipelined CORDIC rotator was implemented. The silicon area of the fabricated pipelined CORDIC rotator core is 2.73 mm(2). This is equivalent to 38 000 inverter gates in the used 0.25 mum BiCMOS technology. The average dynamic power consumption of the fabricated CORDIC rotator is 17 mW at a 2.5 V supply voltage and a 20 Ms/s throughput. Currently, this CORDIC rotator is used as a part of the baseband processor for a project that aims to design a single-chip wireless modem compliant with the IEEE 802.11a standard.
When it comes to the minimax controller design, it would be extremely difficult to obtain such controllers in nonlinear situations. One of the reasons is that the minimax controller should be robust against any kind o...
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When it comes to the minimax controller design, it would be extremely difficult to obtain such controllers in nonlinear situations. One of the reasons is that the minimax controller should be robust against any kind of disturbances in the nonlinear situations. In this paper, we propose a new type of design method of minimax control problems. More precisely, based on the genetic programming and the collective unconscious of Jung, this paper presents a simple design technique to solve the minimax control problems, where the minimax controller may be constructed only paying attention to the minimization process. It would be surprising if the maximization process is not needed in the construction of minimax controllers. Some simulations are given to demonstrate the effectiveness of the proposed design technique with the identification problem and minimax control problems.
A control algorithm has been developed and experimentally validated for guiding swarms of robotic vehicles to acoustic targets. This novel algorithm uses pressure measurements from a set of sensors, each attached to a...
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A control algorithm has been developed and experimentally validated for guiding swarms of robotic vehicles to acoustic targets. This novel algorithm uses pressure measurements from a set of sensors, each attached to a vehicle of the swarm, to deduce energy flows from the environment, and to move in the direction of maximum reflected intensity while controlling constraints between vehicles. The algorithm was validated using a collective of eight hand-placed microphones in an open-space area with a 50-m separation between an emitter and scatterer.
Point-based object representations are a powerful alternative to traditional polygonal object representations. Capturing 3D geometry is a mission-critical content acquisition technique in application domains such as v...
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Point-based object representations are a powerful alternative to traditional polygonal object representations. Capturing 3D geometry is a mission-critical content acquisition technique in application domains such as virtual reality, CAD/CAM, and physical asset management. An important step in capturing models of real objects from a set of still images or video sequences is scene calibration, which consists of obtaining the configuration of the camera's intrinsic parameters--focal length, principal point, and optical aberrations, for example--as well as extrinsic parameters-3D position and orientation relative to the object. A major problem is calibrating long image sequences with many feature occlusions, which is the case for objects on rotating platforms. Furthermore, in continuous sequences, consecutive frames tend to reflect few scene changes. A good feature-tracking algorithm provides a solid base for a robust camera calibration phase. The calibration phase is one of the most important components of a passive 3D capturing system.
The design and implementation of a reconfigurable data acquisition system for a digital relay for power system protection applications are described. A 33% power saving and 31% area reduction are recorded when a modif...
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The design and implementation of a reconfigurable data acquisition system for a digital relay for power system protection applications are described. A 33% power saving and 31% area reduction are recorded when a modified flash analogue-to-digital converter is employed. A further 98% data rate reduction is achieved when the reconfigurable algorithm is applied, enabling an improvement in system efficiency.
Behavioural synthesis is the process whereby the description of a system behaviour is automatically translated into a physical implementation of that system. An essential prerequisite of this process is a language in ...
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Behavioural synthesis is the process whereby the description of a system behaviour is automatically translated into a physical implementation of that system. An essential prerequisite of this process is a language in which to express the design. Traditionally, hardware description languages (HDLs) are used for this, but there is currently much interest in the idea of coercing conventional software languages to do the same job (SystemC is the most prominent example of this). The goal of the research described is to increase the synthesisable description space to support the description of systems utilising dynamic allocation. VHDL supports the concepts of dynamic allocation, and is used as the entry language for the system, although without loss of validity SystemC could have been used. How the structures conventionally associated with dynamic description are implemented and supported is described together with a heap management subsystem that is both space and speed-efficient and which communicates with the user's design via an automatically generated interface.
In this paper a design procedure and experimental implementation of a PID controller is presented. The PID controller is tuned according to damping optimum in order to achieve precise position control of a pneumatic s...
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In this paper a design procedure and experimental implementation of a PID controller is presented. The PID controller is tuned according to damping optimum in order to achieve precise position control of a pneumatic servo drive. It is extended by a friction compensation and stabilization algorithm in order to deal with friction effects. In a case of supply pressure variations, more robust control system is needed. It is implemented by extending the proposed PID controller with friction compensator with the gain scheduling algorithm, which is provided by means of fuzzy logic. The effectiveness of proposed control algorithms is experimentally verified on an industrial cylindrical rodless actuator controlled by a proportional valve.
Giant magnetostrictive actuators are designed and fabricated with home-made TbDyFe magnetostrictive rods. The corresponding static and dynamic characteristics are tested. The total output displacement can be obtained ...
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Giant magnetostrictive actuators are designed and fabricated with home-made TbDyFe magnetostrictive rods. The corresponding static and dynamic characteristics are tested. The total output displacement can be obtained up to 100 mu in and the output force up to 1500 N. The dynamic responses of input and output are accordant and have a small hysteresis. Experiments on active vibration control are implemented in single-degree-of-freedom (DOF) and six-DOF platforms in a flexible space structure. The excellent damping effect, up to 30 dB, proves the good performance of the actuators, the feasibility of the control algorithms, and the reasonable design of the six-DOF platform.
A new and highly efficient algorithm developed under MATLAB for calculating the optical spectra generated by non-resonant optical parametric fluorescence is presented. This algorithm, which allows quick simulation of ...
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A new and highly efficient algorithm developed under MATLAB for calculating the optical spectra generated by non-resonant optical parametric fluorescence is presented. This algorithm, which allows quick simulation of the spectra, is shown to be much more rapid than standard ones. The ways to modify the algorithm for other environments are discussed.
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