91 |
Evaluation of FPGA based Test SystemsStavström, Marcus January 2015 (has links)
This master thesis report covers an investigation of how FPGA based hardware can be used to create customizable measurement instruments, for test of electrical equipment in JAS 39 Gripen. The investigation is done at Saab Support and Services in Arboga. Electrical equipment are gradually replacing functions, which previously have been obtained by other systems, in safety critical environments. Since the functions are safety critical, they require regular testing in order to verify proper operation. The aircraft JAS 39 Gripen, which is manufactured and developed by Saab, is an example of such system. Proper operation of the avionics in it are essential in order to maintain flying safety. There already exist systems today that can verify the functionality of electronics in JAS 39 Gripen. However, there are a number of scenarios where those test systems are somewhat inflexible. More flexible test systems are often desired. This flexibility can be obtained by using congurable hardware, suggestively with FPGAs. This approach is investigated in this master thesis.
|
92 |
Photocrosslinkable nonlinear optical polymers and directly-patternable polyimide dielectricsBell, William Kenneth, III 15 September 2015 (has links)
The development of high-efficiency nonlinear optical (NLO) polymers has opened up many opportunities in the field of electro-optics. However, current NLO polymers do not meet stability requirements for semiconductor integration. In an effort to improve this, we examined the effects of crosslinking following electric field poling. A series of photocrosslinkable polymers bearing side chain chromophores was synthesized, poled and evaluated on the basis of the thermal stability of Second Harmonic Generation. Photoinitiation allowed for control of the onset of curing. Crosslinking was monitored by FTIR and optimal conversion was achieved by applying a slow temperature ramp during exposure. The ultimate stability of the poled polymers was directly related to the number of crosslinking substituents attached to the chromophore pendant group. With two reactive groups per chromophore significant SHG was retained at temperatures beyond the polymer Tg.
In integrated circuit packaging there is a need for directly-patternable polymers of low dielectric constant. Bridging the gap between the high-value silicon chip and circuit board is a substrate comprising alternating layers of metal conductor and polymer dielectric. PMDA-ODA, an aromatic polyimide, meets many of the requirements for integration and can be patterned using a photobase generator (PBG). Due to absorbance by the PMDA-ODA precursor, this PBG must have activity at visible wavelengths. Several oxime urethanes were synthesized and evaluated as candidate long wavelength PBG. These compounds exhibit clean photochemistry and high visible light sensitivity. Unfortunately, carbamate thermal stability is insufficient for patterning PMDA-ODA.
For improved material properties, PMDA-TFMB, a fluorinated polyimide, was also evaluated. Importantly, the polymer precursor is sufficiently transparent to employ thermally-stable near-UV photobases. With photobase, 2.5 micron features were resolved in PMDA-TFMB. An ancillary benefit of this methodology is reduced cure temperature (~200 °C), a traditional drawback of polyimides. This material demonstrates a dielectric constant near 3 and a thermal expansion coefficient (CTE) of approximately 6 ppm/°C in-plane. Through-plane thermal expansion is somewhat problematic, with a CTE of approximately 160 ppm/°C, and will likely require a nanoparticle composite strategy. However, this combination of material and lithographic properties make PMDA-TFMB a promising candidate for this application. / text
|
93 |
A system-level synthetic circuit generator for FPGA architectural analysisMark, Cindy 05 1900 (has links)
Architectural research for Field-Programmable Gate Arrays (FPGAs) tends to use an
experimental approach. The benchmark circuits are used not only to compare different
architectures, but also to ensure that the FPGA is sufficiently flexible to implement the desired variety of circuits.
The most common benchmark circuits used for architectural research are circuits
from the Microelectronics Center of North Carolina (MCNC). These circuits are small;
they occupy less than 3% [5] of the largest available commercial FPGA. Moreover, these
circuits are more representative of the glue logic circuits that were targets of early devices.
This contrasts with the trend towards implementing Systems on Chip (SoCs) on FPGAs
where several functional modules are integrated into a single circuit which is mapped onto one device.
In this thesis, we develop a synthetic system-level circuit generator that connects pre-existing circuits in a realistic manner to build large netlists that share the characteristics of real SoC circuits. This generator is based on a survey of contemporary circuit designs from industrial and academic sources. We demonstrate that these system-level circuits scale well and that their post-routing characteristics match the results of large pre-existing
benchmarks better than the results of circuits from previous synthetic generators.
|
94 |
Pseudoatsitiktinių skaičių generatorių statistinių savybių tyrimas / Analysis of pseudorandom number generator‘s statistical featuresGrigaravičienė, Milda 05 June 2006 (has links)
Pseudorandom number generator‘s statistical features were analyzed in this work. Pseudorandom numbers are applied in many fields, that‘s why it‘s important for them to satisfy following requirements: • to have uniform distribution, • to be uncorrelated. Hypothesis that random numbers are distributed uniformly is checked by Pearson test. Hypothesis that autocorrelation function is equal to zero is checked by Box Ljung test. During investigation it was noticed, that in all ways generated random numbers didn’t have uniform distribution, except linear congriuential generator. Applying different transformations was set, that for combinations v1-v8 when using parabola, transformed random numbers had uniform distribution. Arcsine was the best transformation for nonlinear congriuential generator. While testing hypothesis about autocorrelation function’s equality to zero was noticed, that zero hypothesis rejection or not depends on: • random numbers generation algorithm, • generated sample size, The best generator, which satisfied requirements, is linear congriuential generator, but it is not suitable, because it is too predictable. Nonlinear congruential generator is chosen as the best one, because its statistical features are closest to the linear generator.
|
95 |
An Approach to Quantifying Uncertainty in Estimates of Intensity Duration Frequency (IDF) CurvesAlzahrani, Fahad 13 August 2013 (has links)
Generally urban drainage systems are built to protect urban property and control runoff. Moreover, these systems collect the runoff for storage purposes to serve society through sufficient water supply to meet the needs of demand, irrigation, and drainage. Urban environments are exposed to risks of extreme hydrological events. Therefore, urban water systems and their management are critical. Precipitation data are crucial, but may be prone to errors due to the lack of information e.g., short length of records. In this thesis, a Monte Carlo simulation and regional frequency analysis based on L-moments approach were utilized during the research in order to estimate the uncertainty in the Intensity Duration Frequency (IDF) curves by using historical precipitation data from Environment Canada (EC) weather stations and simulating a new series of data through a weather generator (WG) model. The simulations were then disaggregated from daily into hourly data for extraction of the annual maximum precipitation for different durations in hours (1, 2, 6, 10, 12, and 24). Regional frequency analysis was used to form the sites into groups based on homogeneity test results, and the quantile values were computed for various sites and durations with the return periods (T) in years (2, 10, 20, and 100). As a result, the regional frequency analysis was used to estimate the regional quantile values based on L-moment approach. Moreover, the box and whisker plots were utilized to display the results. When the return periods and durations increased, the uncertainty slightly increased. The historical IDF curves of London site falls within the regional simulated IDF curves. Furthermore, 1000 runs have been generated by using the weather generator.
|
96 |
Improved generation operation of an induction machine based automotive integrated starter alternatorMudannayake, Chathura Prasanna, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2009 (has links)
This thesis proposes improved techniques for controlling of induction machine based integrated starter alternator in order to achieve the challenging requirements of future automotive on-board power system. The proposed techniques are focused on improving DC voltage regulation, maximum power extraction and efficiency improvements. A new sophisticated DC voltage controller that provides tight voltage regulation is proposed. The proposed controller is based on a linearized model for the combined inverter and induction machine. The proposed DC controller is included with speed and flux decoupling and an antiwindup technique. Extensive simulation and experimental results demonstrate the excellent DC voltage control performance of the proposed DC controller over a wide speed range and under various operating conditions. This thesis proposes an improved field weakening implementation which is based on stator voltage control for maximum power extraction in generation mode. The controllers in proposed implementation included use a non-linear dynamic compensator (NDC), stator frequency decoupling and an anti-windup technique. This thesis investigates and eliminates the oscillation in high speed field weakening region caused when large loads are applied. The proposed implementation also provides better regulation for the stator voltage and stable operation over a wide speed range in the generation mode of the ISA. The proposed implementation allows extracting significant amount of additional power compared to conventional field weakening technique. The simulation and experimental results clearly demonstrate the performance of the proposed implementation for ISA. A new loss minimised control method for the integrated starter alternator based on a loss model of the system was developed. The loss model operates in dq − axes and takes into account the inverter and the machine losses. The experimental results demonstrates that proposed loss minimised control provides significant efficiency improvements under light load condition of the ISA. This thesis also presents complete modeling of ISA, an extensive study on induction machine parameter variations and overall control design of the ISA system. The extensive simulation and experimental studies presented in this thesis clearly demonstrates the development of a new ISA which is low-cost, optimised for high efficiency and maximised power over a wide speed range and excellent DC bus voltage regulation under all conditions of generation.
|
97 |
Development and modelling of a thermophotovoltaic system /Mattarolo, Giovanni. January 1900 (has links)
Zugl.: Kassel, University, Diss., 2007.
|
98 |
Fault ride through capabilities of inverter based distributed generation connected to low and medium voltage distribution networksNotholt Vergara, José Antonio January 2008 (has links)
Zugl.: Kassel, Univ., Diss., 2008
|
99 |
A preliminary investigation on 3 Mev. Van de Graaff photoneutron spectra thesis : for the partial fulfillment of the degree of Master of Science in the Institute of Nuclear Science, Tsing Hua University ... /Ma, Pu-Yuan. Pai, Hsiang-Lin. Wang, Shin-Chen. Lee, Wellington S. Chien, Ji-Peng. January 1960 (has links)
Thesis (M.S.)--Tsing Hua University, 1960. / Research done at the University of Michigan.
|
100 |
A methodology to assess the interactions of renewable energy systems dynamics with fluctuating loads /Bouzguenda, Mounir, January 1992 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 247-258). Also available via the Internet.
|
Page generated in 0.0802 seconds