A contextual lightweight arithmetic coder is proposed for lossless compression of medical imagery. Context definition uses causal data from previous symbols coded, an inexpensive yet efficient approach. To further reduce the computational cost, a binary arithmetic coder with fixed-length codewords is adopted, thus avoiding the normalization procedure common in most implementations, and the probability of each context is estimated through bitwise operations. Experimental results are provided for several medical images and compared against state-of-the-art coding techniques, yielding on average improvements between nearly 0.1 and 0.2 bps.

Mobile wireless communication technology is a fast developing field and every day new mobile communication techniques and means are becoming available. In this thesis multi-view video (MVV) is also refers to as 3D video. Thus, the 3D video signals through wireless communication are shaping telecommunication industry and academia. However, wireless channels are prone to high level of bit and burst errors that largely deteriorate the quality of service (QoS). Noise along the wireless transmission path can introduce distortion or make a compressed bitstream lose vital information. The error caused by noise progressively spread to subsequent frames and among multiple views due to prediction. This error may compel the receiver to pause momentarily and wait for the subsequent INTRA picture to continue decoding. The pausing of video stream affects the user's Quality of Experience (QoE). Thus, an error resilience strategy is needed to protect the compressed bitstream against transmission errors. This thesis focuses on error resilience Adaptive Intra Refresh (AIR) technique. The AIR method is developed to make the compressed 3D video more robust to channel errors. The process involves periodic injection of Intra-coded macroblocks in a cyclic pattern using H.264/AVC standard. The algorithm takes into account individual features in each macroblock and the feedback information sent by the decoder about the channel condition in order to generate an MVV-AIR map. MVV-AIR map generation regulates the order of packets arrival and identifies the motion activities in each macroblock. Based on the level of motion activity contained in each macroblock, the MVV-AIR map classifies frames as high or low motion macroblocks. A proxy MVV-AIR transcoder is used to validate the efficiency of the generated MVV-AIR map. The MVV-AIR transcoding algorithm uses spatial and views downscaling scheme to convert from MVV to single view. Various experimental results indicate that the proposed error resilient MVV-AIR transcoder technique effectively improves the quality of reconstructed 3D video in wireless networks. A comparison of MVV-AIR transcoder algorithm with some traditional error resilience techniques demonstrates that MVV-AIR algorithm performs better in an error prone channel. Results of simulation revealed significant improvements in both objective and subjective qualities. No additional computational complexity emanates from the scheme while the QoS and QoE requirements are still fully met.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / compression of the right atrium and ventricle yet their LV function is within normal range. In the setting of normal LV function, symptomatic PE could potentially be the result of right heart compression causing right heart strain. Emphasis should therefore be placed on analyzing the presence and degree of right heart strain in patients with symptomatic pectus excavatum. When assessing for a correlation between the HI, CI, DI, or CCI together and independently with cardiopulmonary impairment, no significant relationships were identified. While it would be highly advantageous for a PE severity index to correlate with objective physiologic impairment, our data suggest that the currently defined indices fail to do so. Data confirming such a correlation would provide a means to measure both the severity of deformity and changes in functional disability in patients with PE. We aim to analyze the correlation between the HI and three new indices with cardiopulmonary impairment using the cardiopulmonary exercise test (CPET). In this study we evaluated the correlation of the Haller, correction, depression, and cardiac compression indices with functional cardiopulmonary impairment using preoperative cardiopulmonary exercise test (CPET) data. We hypothesize that the correction and cardiac compression indices will be strongly correlated with physiologic impairment in patients with PE, thus providing a novel means to measure functional disability as a function of disease severity. Study Design This is a retrospective study of 71 children between the ages of birth and 18 years of age who underwent evaluation for corrective surgery for pectus excavatum between 2010 and 2016 at Phoenix Children’s Hospital. Our final sample underwent preoperative computed tomography (CT) or MRI scan results as well as cardiopulmonary exercise testing. For each patient, the HI, CI, DI, and CCI were independently assessed using the PACS System by a single rater. Preoperative functional capacity was determined by measurement of peak oxygen consumption (VO2max reported as percent predicted) and stroke volume (a surrogate for cardiac output) which was assessed via the O2 pulse (VO2max/heart rate) reported as percent predicted. The possible values range from zero to 100% of the predicted value. Assessments Halller Index Correction Index Depression Index Cardiac Compression Index Correction, Depression, Cardiac Compression and Haller Indices Fail to Correlate with Cardiopulmonary Impairment in Pectus Excavatum Abstract Results Background: Pectus excavatum (PE) affects 1 in every 300 to 1,000 live births with a male to female ratio of 5:1, making it the most common congenital chest wall deformity in children. The standard for determining disease severity has become the Haller Index, which has been shown to poorly correlate with physiologic impairment. Recently, more novel indices have been introduced in an effort to more effectively represent disease burden. We aim to analyze the correlation between these indices and cardiopulmonary impairment in patients with PE using chest CT/ MRI as well as preoperative cardiopulmonary exercise testing data. Conclusions: We found that when assessing for a correlation between the HI, CI, DI, or CCI together and independently with cardiopulmonary impairment, both the linear and multiple regression models failed to identify a statistically significant relationship. While it would be highly advantageous for a PE severity index to correlate with objective physiologic impairment, our data suggest that the currently defined indices fail to do so.

The response of porcine adipose and skeletal muscle tissues to shock compression has been investigated using the plate-impact technique in conjunction with manganin foil pressure gauge diagnostics. This approach has allowed for measurement of the levels of uniaxial stress imparted to both skeletal muscle and rendered adipose tissue by the shock. In addition, the lateral stress component generated within adipose tissue during shock loading has also been investigated. The techniques employed in this study have allowed for equation-of-state relationships to be established for the investigated materials, highlighting non-hydrodynamic behaviour in each type of tissue over the range of investigated impact conditions. While the adipose tissue selected in this work has been shown to strengthen with impact stress in a manner similar to that seen to occur in polymeric materials, the skeletal muscle tissues exhibited a ow strength, or resistance to compression, that was independent of impact stress. Both the response of the adipose material and tested skeletal muscle tissues lie in contrast with the shock response of ballistic gelatin, which has previously been shown to exhibit hydrodynamic behaviour under equivalent loading conditions. Plate-impact experiments have also been used to investigate the shock response of a homogenized variant of one of the investigated muscle tissues. In the homogenized samples, the natural structure of skeletal muscle tissue, i.e. a fibrous and anisotropic composite, was heavily disrupted and the resulting material was milled into a fine paste. Rather than matching the response of the unaltered tissues, the datapoints generated from this type of experiment were seen to collapse back on to the hydrodynamic response predicted for skeletal muscle by its linear equation-of-state (Us = 1.72 + 1.88up). This suggests that the resistance to compression apparent in the data obtained for the virgin tissues was a direct result of the interaction of the shock with the quasi-organized structure of skeletal muscle. A soft-capture system has been developed in order to facilitate post-shock analysis of skeletal muscle tissue and to ascertain the effects of shock loading upon the structure of the material. The system was designed to deliver a one-dimensional, at-topped shock pulse to the sample prior to release. The overall design of the system was aided by use of the non-linear and explicit hydrocode ANSYSR AUTODYN. Following shock compression, sections of tissue were imaged using a transmission electron microscope (TEM). Both an auxetic-like response and large-scale disruption to the I-band/Z-disk regions within the tissue's structure were observed. Notably, these mechanisms have been noted to occur as a result of hydrostatic compression of skeletal muscle within the literature.

Swath bathymetry sidescan (SBS) sonar and the angle-of-arrival processing that underlies these systems has the capability to produce much higher resolution three dimensional imagery and bathymetry than traditional beamformed approaches. However, the performance of these high resolution systems is limited by signal-to-noise ratio (SNR) and they are also susceptible to multipath interference. This thesis explores two methods for increasing SNR and mitigating multipath interference for SBS systems. The first, binary coded pulse transmission and pulse compression is shown to increase the SNR and in turn provide reduced angle variance in SBS systems. The second, transmit beamforming, and more specifically steering and shading, is shown to increase both acoustic power in the water and directivity of the transmitted acoustic radiation. The transmit beamforming benefits are achieved by making use of the 8-element linear angle-of-arrival array typical in SBS sonars, but previously not utilized for transmit. Both simulations and real world SBS experiments are devised and conducted and it is shown that in practice pulse compression increases the SNR, and that transmit beamforming increases backscatter intensity and reduces the intensity of interfering multipaths. The improvement in achievable SNR and the reduction in multipath interference provided by the contributions in this thesis further strengthens the importance of SBS systems and angle-of-arrival based processing, as an alternative to beamforming, in underwater three dimensional imaging and mapping. / Graduate / 0544 / 0547 / mark.butowski@gmail.com

Previous research regarding the utility of non-linear frequency compression in hearing aids has revealed conflicting results for speech recognition, marked by high individual variability. The aims of the study were to determine the effect of non-linear frequency compression on aided speech recognition in noise and listening effort using a dual-task test paradigm and to determine if listener variables of hearing loss slope, working memory capacity, and age predicted performance with non-linear frequency compression. 17 older adults with symmetrical sensorineural hearing loss were tested in the sound field using hearing aids. Speech recognition in noise and listening effort were measured by adapting the Revised Speech in Noise Test into recognition/recall dual-task paradigm. On average, speech recognition in noise performance significantly improved with the use of non-linear frequency compression. Individuals with steeply sloping hearing loss received more recognition benefit. Recall performance also significantly improved at the group level with non-linear frequency compression revealing reduced listening effort. Older participants within the study cohort received less recall benefit than the younger participants. Evidence supports individualized selection of non-linear frequency compression, with results suggesting benefits in speech recognition for individuals with steeply sloping hearing losses and in listening effort for younger individuals.

[pt] É realizado um estudo teórico experimental sobre motores a combustão interna operando com taxa de compressão variável. É feita uma análise teórica sobre determinado mecanismo que permite variar a taxa de compressão. Para tal foi utilizado um programa de simulação para motores com ignição por centelha. No presente trabalho o modelo de simulação foi aprimorado, com a inclusão de previsão de detonação, de emissão de hidrocarbonetos, do cálculo da potencia de atrito, assim como a inclusão do dispositivo do mecanismo de taxa de compressão variável, entre outras alterações. Uma parte experimental foi também realizada, como o objetivo de validar os resultados do modelo teórico e de quantificar os benefícios proporcionados pelo mecanismo em questão. Para tal um motor de pesquisa de combustível – motor CFR – foi utilizado. Uma comparação dos resultados teóricos e experimentais obtidos no presente trabalho com os de outros pesquisadores é também apresentada. / [en] The present work is concerned with a theoretical and expererimental study of variable compression ratio spark ignition internal combustion engines. A theoretical analysis of the engine, operating with a mechanism allows for variable compression ratio, is carried out. For that a simulation program is utilized. In the present work the simulation model was updated with the inclusion of friction, knocking and hidrocarbon emission models, among other things. An experimental work was also carried out, with a CFR engine. The objective was a wo-fold to validade the results of the theoretical model and to assens the benefits of running an engine with variable compression ratio. A comparison is also made between the rrsults of the present work and those from other authors.

We are surrounded by an increasing number of devices and applications that produce a huge quantity of machine generated data. Almost all the machine data contains some element of security information that can be used to discover, monitor and investigate security events.The work proposes a pseudo-random access compressed storage method for log data to be used with an information retrieval system that in turn provides the ability to search and correlate log data and the corresponding events. We explain the method for converting log files into distinct events and storing the events in a compressed file. This yields an entry identifier for each log entry that provides a pointer that can be used by indexing methods. The research also evaluates the compression performance penalties encountered by using this storage system, including decreased compression ratio, as well as increased compression and decompression times.

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. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate