published_or_final_version / Electrical Engineering / Master / Master of Philosophy

published_or_final_version / Computer Science and Information Systems / Master / Master of Philosophy

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

The objective of this research project is to investigate novel concepts of determining fibre assembly mechanical properties at woven fabric at meso-scale, viz. yarns and unit-cell. In order to carry out this investigation three instruments were developed and these are presented in subsequent chapters of this thesis. Initially, an instrument was built in order to explore the buckling technique on yarns and fabrics. The data obtained was converted into pure bending output through a proposed non-linear planar elastica model. It was found that the data obtained were in agreement with data obtained from other measuring technique already available in the industry, viz. Pure Bending tester (KES FB2) from the Kawabata Evaluation System. This investigation also found that the buckling technique offers some advantages when compared with the bending tester. Furthermore, the yarn compression method was also explored. A Yarn Compression tester (YCT) was developed in order to carry out this study. This instrument induces transverse compression upon the yarn by means of a probe, which results in a compression versus thickness curve. An, additional feature was introduce on the YCT, such as the use of a digital camera that allows the yarn lateral spreading to be determined as the yarn is compressed. This feature may be used to calculate the Poisson’s ratio, which can be used as an input value for future compression models. Good agreement was found between the proposed yarn compression technique and data obtained from the Kawabata compression tester.Finally, yarn torsional technique was explored by means of developing a Yarn Torsion tester (YTT). It was found that data obtained for this instrumentation were in agreement with a linear model proposed by Postle et al. This investigation may allow future research to continue by means of proposing a torsion mathematical model.

No description available.

Problems at the intersection of compression and statistical inference recur frequently due to the concurrent use of signal and image compression and classification algorithms in many applications. This dissertation addresses two such problems: statistical inference on compressed data, and rate-allocation for joint compression and classification.Features of the JPEG2000 standard make possible the development of computationally efficient algorithms to achieve such a goal for imagery compressed using this standard. We propose the use of the information content (IC) of wavelet subbands, defined as the number of bytes that the JPEG2000 encoder spends to compress the subbands, for content analysis. Applying statistical learning frameworks for detection and classification, we present experimental results for compressed-domain texture image classification and cut detection in video. Our results indicate that reasonable performance can be achieved, while saving computational and bandwidth resources. IC features can also be used for preliminary analysis in the compressed domain to identify candidates for further analysis in the decompressed domain.In many applications of image compression, the compressed image is to be presented to human observers and statistical decision-making systems. In such applications, the fidelity criterion with respect to which the image is compressed must be selected to strike an appropriate compromise between the (possibly conflicting) image quality criteria for the human and machine observers. We present tractable distortion measures based on the Bhattacharyya distance (BD) and a new upper bound on the quantized probability of error that make possible closed form expressions for rate allocation to image subbands and show their efficacy in maintaining the aforementioned balance between compression and classification. The new bound offers two advantages over the BD in that it yields closed-form solutions for rate-allocation in problems involving correlated sources and more than two classes.

L'??tude fine des fluctuations de courant dans les petites composantes ??lectroniques est un excellent moyen de tester notre compr??hension du transport ??lectronique quantique. Lorsque la fr??quence est suffisamment ??lev??e, ce qui est mesur?? en laboratoire n???est plus un courant d?????lectrons mais un champ ??lectromagn??tique caus?? par l???agitation des ??lectrons. Faire un pont entre l???optique en terme de photons et l?????lectronique quantique est l???objectif dans le laboratoire de Bertrand Reulet. Ce m??moire de ma??trise traite des fluctuations de courant d???une jonction tunnel polaris??e en courant et excit??e avec une tension alternative dans les micro-ondes. La nouveaut?? dans ce projet provient du fait que les fluctuations de courant g??n??r??es par la jonction tunnel ont ??t?? mesur??es en phase et en quadrature avec l???excitation micro-onde envoy??e sur l?????chantillon. Il a ??t?? d??montr?? qu???il est possible de faire un parall??le entre les fluctuations du courant ??lectrique et l???optique quantique pour arriver ?? pr??dire le comportement de ces fluctuations en phase et en quadrature. De plus, la pr??sence d?????tat comprim?? ou ??squeez???? sur l???une des quadratures du courant a ??t?? mesur??e exp??rimentalement. Les r??sultats obtenus sont en parfait accord avec la th??orie d??velopp??e.

This thesis describes the successful development and initial evaluation of a proof-of-concept wireless monitoring system for improving the effectiveness and safety of pneumatic compression therapy to help prevent deep vein thrombosis (DVT). In the development, an important objective was to make feasible the practical and commercial deployment of such improved therapy systems in future, by focusing on a cost-effective design and implementation. Over the years, pneumatic compression has been shown to be an effective solution for the prevention of DVT. However, different problems and complications related to the use of commercial pneumatic compression de-vices that typically include automatic pressure controllers and pneumatic compression sleeves have been reported. For example, one study reported a high percentage of improperly applied or nonfunctional pneumatic compression devices in routine usage. Technical problems, non-compliance, and human error were identified as the causes behind the failed therapies. Also, it was reported that dedicated in-service instruction did not improve the proper use of the pneumatic compression controllers and sleeves. In another study, significant unanticipated variations between expected and delivered pneumatic compression therapy were reported: expected therapy delivered only an average of 77.8% of the time during the therapy, and much of the time key values related to the outcome of the therapy were found to have variations great than 10%. Specific hazards have also been reported. For example, one patient developed acute compartment syndrome after wearing a pair of pneumatic compression sleeves with faulty pressure release valves. In another case, epidural analgesia masked a malfunction resulting from a reversed connection between four-way plastic tubing of the sleeves and the controller, exposing a patient to a hazardous pressure of around 300mmHg,blocking all blood flow for a prolonged period of time. Newer models of pneumatic compression sleeves and controllers from various manufacturers claim to improve therapy by, for example, increasing the peak blood flow velocity. However, there is no evidence in the published literature to support such claims. A published review of the literature from1970-2002 reached the conclusion that the most important factors in im-proving therapy with pneumatic compression devices, particularly during and after surgery, were the degree of conformance of delivered therapy to the prescribed therapy, patient compliance, and the appropriateness of the site of compression. The inability to monitor delivered therapy and patient compliance remains a problem in efforts to improve pneumatic compression therapy. The above-described problems were addressed in the successful development of the innovative prototype described in this thesis. This wireless monitoring system should improve the effectiveness and safety of pneumatic compression therapy. Also, innovative aspects of the system design allow for cost-effective integration into existing commercial controllers and sleeves. For example, an innovative and potentially patentable usage and reprocess indicator was developed for pneumatic compression sleeves to significantly improve their safety and to reduce their cost of use per patient.

For digital media, the risk of piracy is aggravated by the ease to copy and distribute the content. Watermarking has become the technology of choice for discouraging people from creating illegal copies of digital content. Watermarking is the practice of imperceptibly altering the media content by embedding a message, which can be used to identify the owner of that content. A watermark message can also be a set of instructions for the display equipment, providing information about the content’s usage restrictions. Several applications are considered and three watermarking solutions are provided. First, applications such as owner identification, proof of ownership, and digital fingerprinting are considered and a fast content-dependent image watermarking method is proposed. The scheme offers a high degree of robustness against distortions, mainly additive noise, scaling, low-pass filtering, and lossy compression. This method also requires a small amount of computations. The method generates a set of evenly distributed codewords that are constructed via an iterative algorithm. Every message bit is represented by one of these codewords and is then embedded in one of the image’s 8 × 8 pixel blocks. The information in that particular block is used in the embedding so as to ensure robustness and image fidelity. Two watermarking schemes designed to prevent theatre camcorder piracy are also presented. In these methods, the video is watermarked so that its display is not permitted if a compliant video player detects the watermark. A watermark that is robust to geometric distortions (rotation, scaling, cropping) and lossy compression is required in order to block access to media content that has been recorded with a camera inside a movie theatre. The proposed algorithms take advantage of the properties of the dual-tree complex wavelet transform (DT CWT). This transform offers the advantages of both the regular and the complex wavelets (perfect reconstruction, approximate shift invariance and good directional selectivity). Our methods use these characteristics to create watermarks that are robust to geometric distortions and lossy compression. The proposed schemes are simple to implement and outperform comparable methods when tested against geometric distortions.

No description available.