• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1694
  • 530
  • 312
  • 259
  • 181
  • 132
  • 116
  • 95
  • 43
  • 20
  • 16
  • 13
  • 12
  • 10
  • 8
  • Tagged with
  • 3998
  • 1139
  • 654
  • 347
  • 346
  • 345
  • 306
  • 303
  • 294
  • 290
  • 286
  • 264
  • 257
  • 244
  • 241
  • 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.
141

Monocular Visual SLAMbased on Inverse DepthParametrizationMonocular Visual SLAMbased on Inverse DepthParametrization

Rivero Pindado, Victor January 2010 (has links)
<p>The first objective of this research has always been carry out a study of visual techniques SLAM (Simultaneous localization and mapping), specifically the type monovisual, less studied than the stereo. These techniques have been well studied in the world of robotics. These techniques are focused on reconstruct a map of the robot enviroment while maintaining its position information in that map. We chose to investigate a method to encode the points by the inverse of its depth, from the first time that the feature was observed. This method permits efficient and accurate representation of uncertainty during undelayed initialization and beyond, all within the standard extended Kalman filter (EKF).At first, the study mentioned it should be consolidated developing an application that implements this method. After suffering various difficulties, it was decided to make use of a platform developed by the same author of Slam method mentioned in MATLAB. Until then it had developed the tasks of calibration, feature extraction and matching. From that point, that application was adapted to the characteristics of our camera and our video to work. We recorded a video with our camera following a known trajectory to check the calculated path shown in the application. Corroborating works and studying the limitations and advantages of this method.</p>
142

Integrated polymeric components for wavelength division multiplexing

Cowin, Michael January 2001 (has links)
No description available.
143

Genetic synthesis of video coding algorithms and architectures

Sriranganathan, Sivakolundu January 1998 (has links)
No description available.
144

Use of function optimization as an adaptive strategy in the state estimation of a mathematical model of a ship

Liew, M. T. January 1988 (has links)
No description available.
145

The design and implementation of multiplierless fir image filters

Landy, A. January 1986 (has links)
No description available.
146

Flexible sampling and adaptive techniques for communication and instrumentation applications

Yardim, Anush January 1997 (has links)
No description available.
147

Methods for the optimisation of filtration systems for pollution control in deep mine environments

Aitken, Robert John January 1994 (has links)
No description available.
148

Laboratory and field investigations into the feeding performance of the Lake Malawi oreochromis

Hartnell, Robert Massey January 1996 (has links)
No description available.
149

Ceramic-carbon nanotube composites and their potential applications

Parham, Hamed January 2012 (has links)
Carbon nanotubes (CNTs) have been the subject of intensive research for nearly two decades, and this is due to their exceptional lightness, large aspect ratio, extraordinary mechanical, electrical, thermal properties and additional multi-functional characteristics. Ceramics have high stiffness and good thermal stability with a relatively low density, and they are an important constituent in the fabrication of advanced composites where high thermal and chemical stability are important. However, brittleness has limited their application in many structural applications. The combination of ceramic (alumina in particular) and CNTs, endeavouring to develop functional composites, offers a very attractive system for research and development. The fabrication of such alumina-CNT composites at bulk scale is therefore highly desirable for industrial applications. However, the synthesis of such composites possesses many technical challenges which need to be addressed. Poor synergy between the matrix and CNTs, potential damage to CNTs, obtaining a uniform and agglomeration-free distribution of CNTs within the matrix, and high cost of CNTs and processes involved in their composite fabrication have proved to be the significant challenges. In this thesis, the focuses are laid on addressing these issues and on the fabrication of specially engineered composites for particular applications such as filter and composites with improved mechanical properties. In this regard, it has been tried to directly fabricate CNTs in different ceramic matrices based on the application requirements. After that, the critical issues and challenges in the fabrication of these functional materials have been clearly investigated and by introducing novel methods and approaches, it has been tried to solve these problems. Also, a new polymer-ceramic-CNT composite has been fabricated by using two different thermoset (epoxy resin) and thermoplastic (polyamide 12) matrices. In this regard, good interfacial bonding between the composite elements along with good wettability of ceramic and CNTs with polymer had to be addressed as critical issues and challenges in the fabrication process. If the adherence at the interface is not strong enough, the material will tear and fail easier. In contrary, a tailored functionalization of CNTs can lead to an improved wettability and as the results, strong interfacial adhesion and bonding between the composite elements. These dominating factors will improve the degree of filling which results in existence of fewer voids inside the composite. These voids will act later as stress points and reduce the composite strength. At the end, the mechanical properties of the fabricated samples have been assessed. The CNT filters have been tested in the removal of bioorganic (yeast cells) and inorganic (heavy metal ions) contaminants from water, and of particulates from air, and they all showed very promising results. More than 99.6% of the air particles (size ranges from 0.3 to 10 µm) were filtered using 300 mm long CNT filter. A complete removal of heavy metal ions from water was reported particularly for single ion. 98% of the yeast cells were filtered. Different factors involved in the filtration efficiency such as ceramic pore size, length of filters, CNT loading and injection rates have also been discussed. Furthermore, the mechanical properties (compression test, hardness and impact test) of the composite materials (including ceramic-CNT, epoxy resin-ceramic-CNT and polyamide-ceramic-CNT composites) have been assessed. During impact test, the epoxy resin-ceramic-CNT composite absorbed 117.2% and 32.7% more energy compared to the pure epoxy resin and epoxy resin-ceramic composite, respectively. The epoxy resin-ceramic-CNT composite sustained 40% more elastic deformation before breakage compared to the epoxy resin-ceramic composite as a result of the CNT reinforcement. The addition of CNTs to the polyamide12-ceramic composite increased its yield stress by 41%. All of these results represent a big leap towards practical applications for the composite reported in the thesis, which may open up new opportunities for CNT engineering at industrial scales, due to the easy fabrication methods introduced and the promising performance they have exhibited.
150

Automatic tuning for linearly tunable filter

Huang, Sung-Ling 30 September 2004 (has links)
A new tuning scheme for linearly tunable high-Q filters is proposed. The tuning method is based on using the phase information for both frequency and Q factor tuning. There is no need to find out the relationship between a filter's passband magnitude and Q. A gm-C biquadratic filter is designed to demonstrate the proposed tuning circuitry. The project includes a phase locked loop (PLL) based frequency tuning loop, reference clock generator, and differential difference amplifier (DDA) for dealing with frequency and Q factor tuning loop and linearly tunable second order gm-C bandpass filter. Simulation results for a 10 MHz prototype filter using AMI 0.5μm process is presented. The chip testing results show that the automatic frequency tuning error is 2.5% for the 10 MHz case.

Page generated in 0.0474 seconds