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841 |
Genetic Approach with Elitist and Extinction Apply to the Design of Active Vibration ControllerChen, Chih-Kang 04 July 2000 (has links)
We use the elitist and extinction policies to improve the simple genetic algorithm in this study. We expect that the search technique can avoid falling into the local maximum due to the premature convergence, and the chance of finding the near-optimal parameter in the larger searching space could be obviously increased. The accelerometer is then taken as the sensor for output measurement, and the designed controller is implemented to actively suppress the vibration of the plain that is due to the excitation effect of the high-speed and precision positioning of the linear motor.
From the computer simulations and the experimented results, it is obvious that the near-optimal controller designed by using genetic approach with elitist and extinction can improve the effect of vibration suppression; the settling time is also decrease. For the vibration suppressions of high-speed precision positioning problems, the results are satisfactory in the cases of short, middle and long distance.
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842 |
An Active Camera Calibration Method with XYZ 3D TableTseng, Ching-I 12 July 2000 (has links)
The technology of machine vision is board applied in many aspects such as industrial inspection, medical image processing, remote sensing and nanotechnology. It recovers useful information about a scene from its two-dimension projections. This recovery requires the inversion of a many-to-one mapping. But we usually lose some important data for not exactly correct mapping. It might occur from lens distortion, rotation and perspective distortion, and non-ideal vision systems. Camera calibration can compensate for these ill-conditions. In this thesis I present an active calibration technique derived from Song¡¦s research (1996) for calibrating the camera intrinsic parameters. It requires no reference object and directly uses the images of the environment. We only have to control the camera acting a series translational motion by the XYZ 3-D table.
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843 |
Study on Catalytic Wet Air Oxidation of Ferrocyanide or 2,4-Dichlorophenol SolutionsLee, Bing-Nan 18 July 2001 (has links)
The objectives of this research were to obtain the optimum operating conditions for a catalytic wet air process and to investigate their reaction kinetics. Either the ferrouscyanide (Fe(CN)64¡Ð) or the 2,4-dichlorophenol (2,4-DCP) solution was treated by the catalytic wet air oxidation (CWAO) process using three metal ions (Cu2+, Ce3+, and Mn2+) as catalysts or with the Mn/Ce composite oxide catalysts, respectively. In addition, the biodegradability of the effluent derived from the CWAO (2,4-DCP) process was studied.
Results show that the effect of addition of the Cu2+ ion on the wet air oxidation (WAO) of Fe(CN)64¡Ð solution is significant because the Cu2+ ion plays in a role of catalyst, which may lower the activation energy (Ea) during the first-stage of the CWAO process. However, either the Ce3+ or Mn2+ ion did an adverse effect on the Fe(CN)64¡Ð removal, even they had a worse removal than that did by the WAO run without any catalyst addition. The Ea value of the first-stage in the WAO of the Fe(CN)64¡Ð solution process was calculated to be 40.5 KJ mol¡Ð1. On the other hand, the Ea values of the CWAO process with an addition of the Cu2+, Ce3+, or Mn2+ ion, were reduced to 14.1, 16.0, and 20.4 KJ mol¡Ð1, respectively. Obviously, the values of Ea can be reduced to promote the pollutants removal by an addition of suitable catalysts into the WAO process.
It was observed that 2,4-DCP is difficult to be decomposed in the thermal pyrolysis process, but the conversion of 2,4-DCP is significant in the WAO process. With an application of the Mn/Ce composite oxide catalyst in the CWAO process to treat the 2,4-DCP solutions resulted in a better removal than that did by the WAO process. The higher the reaction temperature was applied, the higher 2,4-DCP removal was obtained. Also, the catalyst in a higher Mn/Ce molar ratio would increase the removal of 2,4-DCP during the CWAO runs, while the catalyst in a Mn/Ce molar of 7:3 showed the best 2,4-DCP removal of 96.5%. It is suggested that the reaction temperature of the CWAO process could be controlled 40 K lower than that required in the WAO run to reach an equivalent 2,4-DCP removal efficiency.
The Ea value of the WAO of 2,4-DCP process performed in a semi-batch type reactor were 13.6 and 23.7 KJ mol¡Ð1, respectively, for the first-stage and the second-stage reactions. However, the Ea values of the both reaction stages in the CWAO of 2,4-DCP run were reduced to 9.1 and 5.7 KJ mol¡Ð1, respectively. If the CWAO of 2,4-DCP was performed in an up-flowing fixed -bed reactor, a second-order formula was found. Also, the activation energy and the frequency constant of the CWAO of 2,4-DCP run were calculated to be 11.9 KJ mol¡Ð1 and 0.96 sec¡Ð1.
In the Microtox® toxicity tests, the TUa,15 values of the effluent from the CWAO run were below 8.26, when the CWAO process was operated at 433 K and at a space velocity of less than 11.0 hr¡Ð1, and the Mn/Ce (7:3) composite oxide as a catalyst. On the other hand, the toxicity of the 2,4-DCP could be reduced greatly by being treated in the CWAO process over the Mn/Ce (7:3) composite oxide catalyst. It is possible to treat the 2,4-DCP solution in a concentration less than 500 mg L¡Ð1 to meet the discharging regulation standards using a CWAO run, and followed by an activated sludge unit in which the retention time of the wastewater could be sorter than twelve hours.
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844 |
Using Finite-Difference Time-Domain Method to Simulate Microwave CircuitsSu, Hurng-Weei 19 July 2001 (has links)
FDTD is a numerical method that uses the second-order central-difference method to discrete the Maxwell¡¦s equations in differential form, and positioning electromagnetic field in space grids and time grids. It is applied to analyze many electromagnetic problems in time domain. In this report the FDTD method is extended to include lumped-elements (as resistor, inductor, capacity),and nonlinear elements(as diode, transistor) to combine the circuit elements and electromagnetic fields, it¡¦s so called LE-FDTD algorithm. The first, we will introduce the theory derivations and simulate some circuit structures in 2D, and then in order to simulate the real circuits, we will extend this algorithm in 3D to make full-wave analysis.
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845 |
Hybrid Fuzzy PID Controller for an Active Vibration Control System via Genetic AlgorithmsCheng, Chung-Yi 21 June 2002 (has links)
Abstract
We use the non-binary coding ,elitist strategy, increasing mutation rate, extinction, and immigration strategy to improve the simple genetic algorithms in this study. We expect that the search technique can avoid falling into the local optimum due to the premature convergence, and purse the chance that finding the near-optimal parameters in the larger searching space could be obviously increased.
The accelerometer is then taken as the feedback sensor for output measurement, and the designed actuator and the PID fuzzy logic controller (PIDFLC) is implemented to actively suppress the vibration of the supporting mechanism that is due to the excitation effect of the high-speed and precision positioning action of the linear motor. From the computer simulations and the experimental results, it is obvious that the near-optimal PIDFLC controller designed by modified genetic algorithms can improve the effect of the vibration suppression; the settling time is also decrease. For the vibration suppressions of high-speed precision positioning problems, the vibrating supporting mechanism can quickly be stabilized.
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846 |
Effect of Active Elements on Surface Ripple during Electron-Beam WeldChen, Yu-Hung 03 July 2002 (has links)
Abstract
The occurrence of ripples on the workpiece surface after solidification in electron-beam weld or melting is experimentally and analytically investigated. The maximum accelerating voltage and welding current of electron-beam welder are 60kV and 50mA, respectively, while the workpieces are four different materials containing different quantities of sulfur. Using a scale analysis to account for heat transfer and fluid flow induced by different quantities of surface active element in the molten pool. The result predicted results show good agreement with experimental data.
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847 |
Analysis and Application of the FDTD Method combined with the Equivalent Source MethodChang, Yi-Yuan 24 July 2002 (has links)
FDTD is an electromagnetic field computation method with the ability of considering circuit elements. Traditional lump element method is insufficient for simulating circuit. In this thesis, we use equivalent source method to combine non-linear circuit elements like active devices into the FDTD simulation. The advantages of this is powerful and time-saving. The accuracy of this method is checked of transmission line driving by CMOS circuits. By employing this method, we find that it will increase EMI phenomenon by strengthening current of driving load, and the load of coupling line will affect noise due to impedance mismatch.
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848 |
Implementation of Microwave Active/Passive Elements Using the FDTD MethodsWu, Bo-Zhang 03 July 2003 (has links)
The FDTD method is a numerical method that uses the second-order central-difference method to discrete the Maxwell¡¦s equations in differential form, and positioning electromagnetic field in space grids and time grids. It is applied to analyze many electromagnetic problems in time domain. In the thesis, we applied FDTD methods to solve EMC/EMI problems like the interference to a mixer from an antenna, and the packaging effects to a small signal microwave amplifier and so on.
Therefore, we applied equivalent current source approach to simulate each microwave elements at first. And, we extend the approach to field of EMC/EMI. researching the advantages of FDTD methods in Full-Wave analysis.
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849 |
An eighth grade curriculum incorporating logical thinking and active learningKobiela, Marta Anna 30 October 2006 (has links)
With the increasing stress on teachers and students to meet and raise mathematics
standards in schools, especially in the secondary level, the need for strong curricula and
supporting materials for teachers has grown. A good curriculum, however, must do
more than align with state standards and teach to the state exams; it must encourage
students to enjoy mathematics. In an effort to help ease the plague of math anxiety, this
thesis presents an eighth grade curriculum, called MathTAKStic, not only directly
aligning with the Texas state standards, the Texas Essential Knowledge Skills (TEKS),
but also encouraging students to pursue higher level thinking through active learning and
logical thinking. To test the curriculum and find out its usefulness, several lessons were
taught at a middle school. Although the scores of those learning with the curriculum
were not always better than others, MathTAKStic led to a greater increase in studentsâÂÂ
performance compared to those who were not exposed to the lessons, an increased
interest in math and a plethora of ideas for the future. These results were concluded
based on a comparison of studentsâ scores from the previous year to the current year on
the Texas standardized test. Overall, the increase in passing scores of MathTAKStic
students preceded other classes in the same school.
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850 |
Reactivity studies of antitumor active dirhodium compounds with DNA oligonucleotidesKang, Mijeong 25 April 2007 (has links)
The study of the mechanism of action of an antitumor active drug is essential for
improving the efficacy and reducing the side effects of the drug as well as for developing
better alternatives. In this vein, reactions of dirhodium compounds with DNA
oligonucleotides were investigated by the techniques of mass spectrometry, HPLC, and
NMR spectroscopic analytical methods.
The relative reactivities of three dirhodium compounds, namely Rh2(O2CCH3)4,
Rh2(O2CCF3)4, and [Rh2(O2CCH3)2(CH3CN)6](BF4)2, with DNA oligonucleotides were
studied and compared to the clinically used anticancer drugs cisplatin and carboplatin
using both MALDI and ESI mass spectrometric methods. The compound Rh2(O2CCF3)4
exhibits the highest reactivity among the dirhodium compounds, which is comparable to
cisplatin, followed by [Rh2(O2CCH3)2(CH3CN)6](BF4)2, and finally Rh2(O2CCH3)4
which is the least reactive.
Various dirhodium-oligonucleotide adducts were detected with both MALDI and
ESI methods, which involve substitution of different numbers of the original ligands of the given dirhodium compound. ESI MS was found to be a sufficiently soft ionization
method for detecting intact metal adducts, and CID MS-MS was useful for detecting
weakly bound species such as axial adducts [M+Rh2(O2CCH3)4] and for comparing the
relative bond strength between ligands in the metal adduct.
A combination of anion exchange HPLC purification and enzymatic digestion
studies of the adducts of Rh2(O2CCH3)4 with the 5'-CCTTCAACTCTC oligonucleotide
revealed that Rh2(O2CCH3)4 binds to the center or to the ends of the oligonucleotide
sequence by displacement of one or two acetate groups.
Kinetic products of the type [M+Rh2(O2CCH3)3] obtained from the reaction of
Rh2(O2CCH3)4 with 5'-CTCTCAACTTCC were separated by employing both reverse
phase and anion exchange HPLC methods. The adduct that involves binding of the
dirhodium unit to the exocyclic N4 atom of C5 and the N7 of A6 was found to be most
stable whereas other adducts involving binding of C3 or C12 residues are clearly less
stable.
Reaction of cis-[Rh2(DAP)(O2CCH3)3(CH3OH)](O2CCH3) (DAP = 1,12-
diazaperylene) with 5'-CTCTCAACTTCC produced a major adduct in which DAP
group intercalates between 6A and 7A in the double stranded adduct with the rhodium
atom that is not coordinated to the DAP group forming a covalent bond to the N7 atom
of 6A which lends stability to the adduct.
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