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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Closed-loop Real-time Control of a Novel Linear Magnetostrictive Actuator

Chen, Chien-Fan 2010 August 1900 (has links)
This thesis presents the design of various closed-loop real-time control of a novel linear magnetostrictive actuator. The novel linear magnetostrictive actuator which uses Terfenol-D as the magnetostrictive material was developed by Sadighi. It solves the problem of power consumption in a conventional magnetostrictive actuator. However, the control system of this magnetostrictive actuator cannot control the current in the coils, which limits the performances of the real-time position control. In the closed-loop real-time control system proposed in this thesis, the controller is designed depending on the change of current. The closed-loop real-time control design focused on the position control of the active element in the novel linear magnetostrictive actuator. The closed-loop position-control system of the linear magnetostrictive actuator was successfully designed by implementing a closed-loop current-control system as an inner loop of the entire control system. This design offers the flexibility to design various position controllers in the closed-loop position-control system. The closed-loop current-control design uses pulse-width modulation (PWM) signal to change the current in the coils of the novel linear magnetostrictive actuator. By changing the duty ratio of the PWM signal, the current in the coils can be changed from zero to its maximum value. With a current controller using an integrator with a gain of 10, the current can be controlled with high response time and an error of /- 0.01 A. The position-controller design was successfully conducted by using four different approaches. First, a proportional-integral-derivative (PID) controller which was designed by relay-auto tuning method with experiments exhibited a position error of ±1 μm with a 5 μm peak-to-peak position noise. Second, a PID controller which was designed by root-locus can control the position with a position error of /- 3-4 μm with a 5 μm peak-to-peak position noise. Third, a linear variable velocity controller exhibited a position error of /-5 μm with a 5 mu m peak-to-peak position noise. Then, the sliding mode control (SMC) exhibited a position error of /-5 μm with a 5 μm peak-to-peak position noise.
32

Low Power, Fast Locking, and Wide-Range Delay-locked Loop for Clock Generator.

Hsu, Yi-hsi 16 July 2008 (has links)
This thesis presents a delay-locked loop of multi-band selector with wide-locking range and low power dissipation is presented. The architecture of the proposed delay-locked loop consists of phase frequency detector, charge pump, band selector, multi-controlled delay line, and start-up circuit. The multi-band selector is used to extend operation frequency of delay-locked loop by switching the multi-controlled delay line. By using multi-band technology the proposed DLL can provide wider range and lower jitter compared to those of other methods. Frequency can be ranged from 250MHz to 900MHz is using TSMC 0.18um process with 1.8V supply voltage. The other implement is using UMC 90nm 1P9M CMOS process with 1V supply voltage. The frequency can be ranged from 33MHz to 300MHz.
33

A calculus of loop invariants for dense linear algebra optimization

Low, Tze Meng 29 January 2014 (has links)
Loop invariants have traditionally been used in proofs of correctness (e.g. program verification) and program derivation. Given that a loop invariant is all that is required to derive a provably correct program, the loop invariant can be thought of as being the essence of a loop. Being the essence of a loop, we ask the question “What other information is embedded within a loop invariant?” This dissertation provides evidence that in the domain of dense linear algebra, loop invariants can be used to determine the behavior of the loops. This dissertation demonstrates that by understanding how the loop invariant describes the behavior of the loop, a goal-oriented approach can be used to derive loops that are not only provably correct, but also have the desired performance behavior. / text
34

Modellbasierte Software in the Loop Simulation von Werkzeugmaschinen /

Herfs, Werner Josef. January 2010 (has links)
Zugl.: Aachen, Techn. Hochsch., Diss., 2010.
35

The Physical and Mechanical Aspects of Orthodontic Appliances

Bibby, R.E January 1978 (has links)
Magister Scientiae Dentium - MSc(Dent) / These laws were first published in Latin,in 1687.The first law may be literally translated thus, Every body continues in its state of reat or of uniform motion in a straight line ,unless it is compelled to change that state by impressed force. This meano that if a body is at rest it will remain so unless some force acts on it,if in motion ,the velocity of motion must continue uniform unless some force acts to increase it or diminish it. Also the direction of motioA mast continue unchanged and therefom rectilinear unless some force causes it to be diverted. This law therefore supplies us with a definition of force; Force is that which produces or tends to produce, motion 0.' change of motion. Newton's second law of motion may be translated as follows:- Newton's second law of motion may be translated as follows:- The change of motion (produced)is proportional to the impressed force producing it,and pursues the direction in which that force is impressed. This law leads to a method of measuring forces. If we change the velocity with which a mass is moving,we also change its momentum. Change in momentum will serve to measure force.lt seems obvious that whatever change in momentum is produced by a force, twice the force will produce twice the change ,etc.i.e. the change is directly proportional to the force. For a given mass,m,change of momentum ,mv,means change of velocity;the change of velocity per unit time is aceeleration,a;the change in momentum per unit time is therefore malf we employ absolute units (poundals or dynes)this can be shown as; Newton's third law of motion states that 'to every action there is an equaI and opposite reaction'.This law recognises the dual aspect of forces It a tooth is pushed by a finger spring ,the spring is also pushed by the tooth,and an eqpal counter force acts towards the spring unti1 the biology of the system intervenes. This dual stress is called pressure. Retracting incisors against posterior segments it is apparent that the reaction of the posterior segments must be equal and opposite to the incisors.In this case the two forces act away trom each other,and tG this dual stress we give the name tension.
36

Optimal Loop Unrolling for GPGPU Programs

Sreenivasa Murthy, Giridhar 30 September 2009 (has links)
No description available.
37

Self-tuning control with pole-zero placement

Sattar, T. P. January 1986 (has links)
No description available.
38

Digital control of power semiconductor converters

Luo, F. L. January 1986 (has links)
No description available.
39

Neural network techniques for the control and identification of acceleration sensors

Gaura, Elena Ioana January 2000 (has links)
No description available.
40

An algebraic model for the homology of pointed mapping spaces out of a closed surface

Boyle, Méadhbh January 2008 (has links)
No description available.

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