A new automatic compression scheme that adapts to any image set is presented in this thesis. The proposed scheme requires no a priori knowledge on the properties of the image set. This scheme is obtained using a unified graph-theoretical framework that allows for compression strategies to be compared both theoretically and experimentally. This strategy achieves optimal lossless compression by computing a minimum spanning tree of a graph constructed from the image set. For lossy compression, this scheme is near-optimal and a performance guarantee relative to the optimal one is provided. Experimental results demonstrate that this compression strategy compares favorably to the previously proposed strategies, with improvements up to 7% in the case of lossless compression and 72% in the case of lossy compression. This thesis also shows that the choice of underlying compression algorithm is important for compressing image sets using the proposed scheme. / x, 77 leaves ; 29 cm.

Work conducted as part of this thesis evaluated the lifting techniques of paramedics using a novel link-segment model that was validated against a commercially available software package, 3D Static Strength Prediction Program (3DSSPP). Twenty-five paramedics visited the Biomechanics Lab at Queen’s University to participate in testing sessions mimicking the daily lifting and carrying tasks performed by paramedics on the job. Participants were outfitted with the Xsens Motion Tracking System and asked to lift and carry bags ranging from 5-20kg. Output from the Xsens system was used in a 3D-inverse dynamic model to estimate loading at the L5/S1 joint. The compressive and shear force estimates at this joint are of particular interest given their correlation with low back pain and injury. Across all conditions the greatest compressive forces were seen during bag pickup and bag release. Additionally, reaching forward 50 cm at pickup increased peak spinal compressive loads by nearly 300N and 500N for a 5kg and 10kg handbag respectively. Not surprisingly, at bag release greater trunk lean values were correlated with higher compressive force estimates. Single-shoulder backpack carries showed similar loading characteristics when compared to double-shoulder backpack carries. Shear force estimates remained well below acceptable levels across all conditions. Based on paramedic feedback, a supplementary testing session was performed with a single participant to evaluate multi-bag carries and stair climbing. The results of this testing session showed that loading was reduced at pickup and release when the load was distributed across two bags. This research led to the development of four recommendations that have been presented to the Association of Municipal Emergency Medical Services of Ontario. 1. Paramedics should not lift single bags or a combination of bags that exceed 20kg. 2. Prior to lifting, bags should be located as close to the paramedic as possible. 3. When placing bags on the ground and when picking bags up off of the ground, paramedics should use a squat lift technique to prevent forward and side bending. 4. When multiple bags are carried the load should be evenly distributed within bags and across sides of the body. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2011-09-30 19:26:18.28

The performance characteristics of a diesel fuel piloted syngas compression ignition engine are presented in this thesis. A stock Hatz 1D81 engine was converted to operate in dual fuel mode through the elimination of the governor system and addition of an in-cylinder pressure transducer and custom intake system to facilitate the mixing of the gaseous fuel and combustion air. The engine was run on a Superflow water brake dynamometer and benchmarked with diesel to compare against manufacturer specifications. This was followed by dual fuel operation on methane and syngas, with the results being compared through performance characteristics. When operated on methane, the engine attained higher peak in-cylinder pressures along with higher torque, power, and thermal efficiency values for equal equivalence ratios. It was necessary to use greater amounts of syngas to reach comparable results with methane due to the lower energy content of syngas. The ignition delay was greater for syngas, and the onset of knock occurred earlier with syngas in comparison to methane. The heat release, Q, was comparable for both fuels and the exhaust gas emissions were significantly lower for operation with syngas. With emphasis on clean engine operation, syngas operation proved to be viable due to its renewable nature, significantly lower exhaust gas emissions, equal heat release characteristics, and larger useable operating range when compared to methane. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-05-28 15:02:49.227

The need to compactly represent 3D data is motivated by the ever-increasing size of these data. Furthermore, for large data sets it is useful to randomly access and process a small part of the data. In this thesis we propose two methods of compactly representing 3D data while allowing random access. The first is the multiresolution sphere-packing tree (MSP-tree). The MSP-tree is a multiresolution 3D hierarchy on regular grids based on sphere-packing arrangements. The grids of the MSP-tree compactly represent underlying point-sampled data by using more efficient grids than existing methods while maintaining high granularity and a hierarchical structure that allows random access. The second is distance-ranked random-accessible mesh compression (DR-RAMC). DR-RAMC is a lossless simplicial mesh compressor that allows random access and decompression of the mesh data based on a spatial region-of-interest. DR-RAMC encodes connectivity based on relative proximity of vertices to each other and organizes both this proximity data and vertex coordinates using a k-d tree. DR-RAMC is insensitive to a variety of topological mesh problems (e.g. holes, handles, non-orientability) and can compress simplicial meshes of any dimension embedded in spaces of any dimension. Testing of DR-RAMC shows competitive compression rates for triangle meshes and first-ever random accessible compression rates for tetrahedral meshes. / Thesis (Ph.D, Computing) -- Queen's University, 2012-07-17 15:28:39.406

The ability to communicate over a low bit-rate transmission channel has become the order of the day. In the past, transmitted data over a low bit-rate transmission channel, such as a wireless link, has typically been reserved for speech and data. However, there is currently a great deal of interest being shown in the ability to transmit streaming video over such a link. These transmission channels are generally bandwidth limited hence bit-rates need to be low. Video on the other hand requires large amounts of bandwidth for real-time streaming applications. Existing Video Compression standards such as MPEG-l/2 have succeeded in reducing the bandwidth required for transmission by exploiting redundant video information in both the spatial and temporal domains. However such compression systems are geared towards general applications hence they tend not to be suitable for low bit-rate applications. The objective of this work is to implement such a system. Following an investigation in the field of video compression, existing techniques have been adapted and integrated into an application specific low bit-rate video compression system. The implemented system is application specific as it has been designed to track vehicles of reasonable size within an otherwise static scene. Low bit-rate video is achieved by separating a video scene into two areas of interest, namely the background scene and objects that move with reference to this background. Once the background has been compressed and transmitted to the decoder, the only data that is subsequently transmitted is that that has resulted from the segmentation and tracking of vehicles within the scene. This data is normally small in comparison with that of the background scene and therefore by only updating the background periodically, the resulting average output bit-rate is low. The implemented system is divided into two parts, namely a still image encoder and decoder based on a Variable Block-Size Discrete Cosine Transform, and a context-specific encoder and decoder that tracks vehicles in motion within a video scene. The encoder system has been implemented on the Philips TriMedia TM-1300 digital signal processor (DSP). The encoder is able to capture streaming video, compress individual video frames as well as track objects in motion within a video scene. The decoder on the other hand has been implemented on the host PC in which the TriMedia DSP is plugged. A graphic user interface allows a system operator to control the compression system by configuring various compression variables. For demonstration purposes, the host PC displays the decoded video stream as well as calculated rate metrics such as peak signal to noise ratio and resultant bit-rate. The implementation of the compression system is described whilst incorporating application examples and results. Conclusions are drawn and suggestions for further improvement are offered. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.

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This thesis compares the speech quality of Code Excited Linear Predictor (CELP, Federal Standard 1016) speech coder with a new wavelet method to compress speech. The performances of both are compared by performing subjective listening tests. The test signals used are clean signals (i.e. with no background noise), speech signals with room noise and speech signals with artificial noise added. Results indicate that for clean signals and signals with predominantly voiced components the CELP standard performs better than the wavelet method but for signals with room noise the wavelet method performs much better than the CELP. For signals with artificial noise added, the results are mixed depending on the level of artificial noise added with CELP performing better for low level noise added signals and the wavelet method performing better for higher noise levels.

Time-frequency analysis is a powerful tool for signal analysis and processing. The Fourier transform and wavelet transforms are used extensively as is the Short-Time Fourier Transform (or Gabor transform). In 1996 the Stockwell transform was introduced to maintain the phase of the Fourier transform, while also providing the progressive resolution of the wavelet transform. The discrete orthonormal Stockwell transform is a more efficient, less redundant transform with the same properties. There has been little work on mathematical properties of the Stockwell transform, particularly how it behaves under operations such as translation and modulation. Previous results do discuss a resolution of the identity, as well as some of the function spaces that may be associated with it [2]. We extend the resolution of the identity results, and behaviour under translation, modulation, convolution and differentiation. boundedness and continuity properties are also developed, but the function spaces associated with the transform are unrelated to the focus of this thesis. There has been some work on image processing using the Stockwell transform and discrete orthonormal Stockwell transform. The tests were quite preliminary. In this thesis, we explore some of the mathematics of the Stockwell transform, examining properties, and applying it to various continuous examples. The discrete orthonormal Stockwell transform is compared directly with Newland’s harmonic wavelet transform, and we extend the definition to include varitions, as well as develop the discrete cosine based Stockwell transform. All of these discrete transforms are tested against current methods for image compression.