Stent implantation is the most common treatment of coronary heart disease, one of the major causes of death worldwide. During a stenting procedure, the clinician inserts interventional devices inside the patient's vasculature. The navigation of the devices inside the patient's anatomy is monitored in real-time, under X-ray fluoroscopy. Three specific interventional devices play a key role in this procedure: the guide-wire, the angioplasty balloon and the stent. The guide-wire appears in the images as a thin curvilinear structure. The angioplasty balloon, that has two characteristic markerballs at its extremities, is mounted on the guide-wire. The stent is a 3D metallic mesh, whose appearance is complex in the fluoroscopic images. Stents are barely visible, but the proper assessment of their deployment is key to the procedure. The objective of the work presented in this thesis is twofold. On the first hand, we aim at designing, studying and validating image processing techniques that improve the visualization of stents. On the second hand, we study the processing of curvilinear structures (like guide-wires) for which we propose a new image processing technique. We present algorithms dedicated to the 2D and 3D visualization of stents. Since the stent is hardly visible, we do not intend to directly locate it by image processing means in the images. The position and motion of the stent are inferred from the location of two landmarks: the angioplasty balloon and of the guide-wire, which have characteristic shapes. To this aim, we perform automated detection, tracking and registration of these landmarks. The cornerstone of our 2D stent visualization enhancement technique is the use of the landmarks to perform motion compensated noise reduction. We evaluated the performance of this technique for 2D stent visualization over a large database of clinical data (nearly 200 cases). The results demonstrate that our method outperforms previous state of the art techniques in terms of image quality. A comprehensive validation confirmed that we reached the level of performance required for the commercial introduction of our algorithm. It is currently deployed in a large number of clinical sites worldwide. The 3D stent visualization that we propose, uses the landmarks to achieve motion compensated tomographic reconstruction. We show preliminary results over 22 clinical cases. Our method seems to outperform previous state of the art techniques both in terms of automation and image quality. The previous stent visualization methods involve the segmentation of the part of the guide-wire extending through the stent. We propose a generic tool to process such curvilinear structures that we call the Polygonal Path Image (PPI). The PPI relies on the concept of locally optimal paths. One of its main advantages is that it unifies the concepts of several previous state of the art techniques in a single formalism. Moreover the PPI enables to control the smoothness and the length of the structures to segment. Its parametrization is simple and intuitive. In order to fully benefit from the PPI, we propose an efficient scheme to compute it. We demonstrate its applicability for the task of automated guide-wire segmentation, for which it outperforms previous state of the art techniques

This paper conducts an analysis of the short-term Firm Value Enhancement that companies experience during large-scale advertising campaigns, such as the Super Bowl. The findings suggest that these firms may experience a positive or negative return during the days after a large event, by signaling to investors and consumers the value of their firm through their advertisements. Some of the highlights include an approximately – 5% return for Super Bowl Advertisers on the Monday after the event, and underperformance during the two weeks surrounding the event.

The aim of the research was to design and assess the effectiveness of a hope enhancement programme for a group of adults and the resulting influence on their general psychological well-being. The purpose of the programme was to increase hope, as conceptualised by Snyder et al. (1991), by enhancing participants' abilities to set feasible goals, planning ways to reach those goals (pathways) and increasing determination and motivation (agency) towards goal achievement. The workshop-format programme, presented by the researcher, consisted of six two-hour sessions spread over five days. The programme was developed through incorporating suggestions from existing Hope literature together with health psychological and positive psychology principles. In order to determine the impact of the programme, four measurement instruments were used, namely the Hope Scale, the Hunter Opinions and Personal Expectations Scale (HOPES), the Satisfaction with Life Scale (SWLS) and the Sense of Coherence scale (SOC-29). A pre and post-test design included an experimental group (n = 8), control group (n = 8) and 'chat' group (n = 8). Prior to group compilation, screening interviews were conducted with interested participants to exclude those who had recently experienced trauma or displayed overt signs of psychological pathology. The control group received no intervention, while the 'chat' group, of which the researcher was also a member, was allowed to discuss topics of their choosing. The study groups comprised both men and women of different ages and socio-economic status. All participants were White and Afrikaans speaking. Descriptive statistics, psychometric analysis of the measuring instruments and significant differences between groups were calculated with the assistance of the STATISTICA (version 6) computer programme (Statsoft Inc., 2003). Reliability indices compared well with those recorded in the literature for the various scales. For the experimental group, the findings indicated an increase in the hope levels as reflected by significant improvement on the Hope Scale and the Hopefulness subscale of the HOPES. Subjective feedback from the group confirmed these findings. Psychological well-being improved, as shown by a significant increase in Sense of Coherence (SOC-29) along with a positive change in Satisfaction with Life (SWLS). Neither the control nor experimental groups revealed any significant changes. It was established that the hope enhancement programme is effective in increasing the levels of hope and general psychological well-being of a group of adults relatively free of psychological pathology. Considering the findings, it is recommended that future wellness intervention should not focus solely on individuals with established psychological pathology, but also consider a preventative approach within the average population. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2005.

The absorption enhancing ability of chitosan, a linear polysaccharide, is mediated by protonated amino groups on the C-2 position of the molecules that induce interaction with the anionic sites on the cell membranes to subsequently alter tight junction integrity. In neutral and basic environments, such as those found in the small and large intestines, most chitosan molecules will lose their charge and precipitate from solution rendering it ineffective as an absorption enhancer. To increase the solubility of this polymer, methylation of the amino groups on the C- 2 position was proposed. A partially quaternised and water soluble derivative of chitosan, N-trimethyl chitosan chloride (TMC), which exhibits superior solubility in a basic environment compared with other chitosan salts was synthesised and included in a chitosan microbead solid drug delivery system. Two TMC derivatives were synthesised by reductive methylation from high and medium molecular weight Chitoclear™ chitosan respectively. The degree of quaternisation calculated from the 1H-NMR spectra for the medium molecular weight TMC (TMC-M) and the high molecular weight TMC (TMC-H) polymers were 74.7 % and 48.5 % respectively. The mean molecular weights of the synthesised TMC-M and TMC-H polymers were 64 100 g/mole and 233 700 g/mole respectively. The effect of different concentrations TMC-M and TMC-H on chitosan microbeads was studied with results obtained from scanning electron microscopy (SEM), TMC loading capacity and microbead swelling behaviour. After selection of the most suitable TMC concentration, the effect of varying concentration (0.1, 0.2 and 0.5 %) additives on TMC and ibuprofen release was studied. Commonly used modified cellulose gum (Ac-di-sol®(ADS)), sodium starch glycolate (Explotab®(EXP)) and ascorbic acid (AA) were added as disintegrants to different microbead formulations to promote release of both the ibuprofen as model drug and TMC from the beads. It was noticed that the loading (% drug loading capacity) of TMC-M was much lower than that obtained with TMC-H while the inclusion of different additives in varying concentrations did not seem to have a profound influence on the loading of either TMC-M or TMC-H. It was further noticed from the fit factors (f1 and f2) for dissolution profiles of eighteen chitosan microbead variations that the formulation containing TMC-H and 0.5% (w/v) ascorbic acid was the only formulation with a significantly higher ibuprofen and TMC-H release profile compared to all other formulations tested. The chitosan microbead formulation containing 2%(w/v) TMC-H and 0.5 % (w/v) ascorbic acid (H-AA-0.5) was used for in vitro absorption studies through rat intestine in Sweetana-Grass diffusion chambers. Chitosan containing TMC-H (no ascorbic acid) (CHIT-H) only and a plain chitosan microbead (CHIT) formulation was used as control formulations during the in vitro studies. Although the H-AA-0.5 formulation exhibited the highest transport rate for ibuprofen, the mean rate of transport (P app) obtained from the two formulations containing TMCH (CHIT-H and H-AA-0.5) showed no significant difference in the transport rate of ibuprofen. Compared to the CHlT formulation as control, both formulations containing TMC-H exhibited increased ibuprofen transport across in vitro rat jejunum. However, a statistical significant increase in transport was obtained only from the H-AA-0.5 formulation in comparison with the CHlT formulation. It can be concluded that the combination of high molecular weight TMC with a low degree of quaternisation and ascorbic acid (0.5% w/v) in a chitosan microbead lead to a statistical significant increase in the in vitro transport rate of ibuprofen through rat jejunum. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2006.

The estimation of power spectral densities is a critical step in many speech enhancement algorithms. The demand for multi-channel speech enhancement systems is high with applications in teleconferencing, cellular phones, and hearing aids. The first objective of the thesis is to develop a general multi-channel framework to solve for the diffuse noise power spectral densities whenever the spatial correlation or coherence matrix is pre-estimated and the number of speakers is less than the number of microphones. The second objective is to develop closed-form analytical solutions. The performance of the developed algorithms is evaluated with pre-existing algorithms using prescribed performance measures.

The performance, reliability, and ubiquity of automatic speech recognition systems has flourished in recent years due to steadily increasing computational power and technological innovations such as hidden Markov models, weighted finite-state transducers, and deep learning methods. One problem which plagues speech recognition systems, especially those that operate offline and have been trained on specific in-domain data, is the deleterious effect of noise on the accuracy of speech recognition. Historically, robust speech recognition research has focused on traditional noise types such as additive noise, linear filtering, and reverberation. This thesis describes the effects of nonlinear dynamic range compression on automatic speech recognition and develops a number of novel techniques for characterizing and counteracting it. Dynamic range compression is any function which reduces the dynamic range of an input signal. Dynamic range compression is a widely-used tool in audio engineering and is almost always a component of a practical telecommunications system. Despite its ubiquity, this thesis is the first work to comprehensively study and address the effect of dynamic range compression on speech recognition. More specifically, this thesis treats the problem of dynamic range compression in three ways: (1) blind amplitude normalization methods, which counteract dynamic range compression when its parameter values allow the function to be mathematically inverted, (2) blind amplitude reconstruction techniques, i.e., declipping, which attempt to reconstruct clipped segments of the speech signal that are lost through non-invertible dynamic range compression, and (3) matched-training techniques, which attempt to select the pre-trained acoustic model with the closest set of compression parameters. All three of these methods rely on robust estimation of the dynamic range compression distortion parameters. Novel algorithms for the blind prediction of these parameters are also introduced. The algorithms' quality is evaluated in terms of the degree to which they decrease speech recognition word error rate, as well as in terms of the degree to which they increase a given speech signal's signal-to-noise ratio. In all evaluations, the possibility of independent additive noise following the application of dynamic range compression is assumed.

Syftet med föreliggande studie var att empiriskt undersöka en teoretisk modell för korrelationer mellan dispositionell mindfulness, påverkansmekanismer och idrottspsykologiska färdigheter (Birrer, Röthlin & Morgan, 2012). Modellen testas genom att (1) undersöka korrelationer mellan dispositionell mindfulness och påverkansmekanismer (Emotionsreglering, Klarsynthet och Ältande). (2) Undersöka korrelationer mellan påverkansmekanismer och idrottspsykologiska färdigheter (Motoriska färdigheter, Anspänningsreglering, Motivation och Copingförmåga). (3) Dessutom undersöktes även korrelationer mellan idrottspsykologiska färdigheter och självskattad idrottsprestation (Tävlings- respektive träningsprestation). I studien deltog 242 elitidrottare från idrottsföreningar i sydvästra Sverige. Den aktuella studien stöder Birrer med kollegors (2012) modell då resultatet (1) visade signifikanta korrelationer mellan dispositionell mindfulness och samtliga tre påverkansmekanismer. (2) Vidare visade resultatet i aktuell studie att Emotionsreglering är relaterat till bättre Copingförmåga, Inre motivation och Anspänningsreglering. Resultatet visade att bättre Klarsynthet om sitt inre känsloliv är relaterat till bättre Copingförmåga, Inre motivation och Anspänningsreglering. Resultatet visade även att mindre Ältande är relaterat till bättre Copingförmåga och Anspänningsreglering. (3) Bättre Copingförmåga och högre grad av Yttre motivation visades vara relaterat till högre självskattad tävlingsprestation. Till sist visade resultatet att bättre Copingförmåga och högre grad av Inre motivation är relaterat till högre självskattad träningsprestation. Resultatet diskuterades i relation till forskning och teoretiska referensramar. / The purpose of present study was to empirically examine a theoretical model for correlations between dispositional mindfulness, impact mechanisms and sport psychological skills (Birrer, Röthlin & Morgan, 2012). The model is tested by (1) to examine the correlations between dispositional mindfulness and impact mechanisms (Self-regulation, Clarity and Rumination). (2) To examine correlations between impact mechanisms and sport psychological skills (Motor Control Skills, Arousal Regulation Skill, Motivation and Coping Skills). (3) In addition was also correlations between skills and self-rated sport performance (competitive and training performance) examined. The study involved 242 competitive athletes from sports clubs in southwestern Sweden. The current study supports Birrer with colleagues' (2012) model when the results (1) showed significant correlations between dispositional mindfulness and all three impact mechanisms. (2) Furthermore, the results showed that Self-Regulation is related to better Coping Skills, Intrinsic Motivation and Arousal Regulation Skill. The results showed that better Clarity about its inner emotional life is related to better Coping Skills, Intrinsic Motivation and Arousal Regulation Skill. The results also showed that less Rumination is related to better Coping Skills and Arousal Regulation Skill. (3) Better Coping Skills and higher levels of External Motivation appeared to be related to higher self-rated competitive performance. Finally, the results showed that better Coping Skills and higher levels of Intrinsic Motivation are related to higher self-rated exercise performance. The results were discussed in relation to research and theoretical frameworks.

A learner in an informal learning environment, such as a museum, encounters various challenges. After initial assessment, a set of methods were proposed that may enhance a learner’s experience in a museum using computer aided technologies. The most important insight was the need to support the museum visitor in three phases of activity: prior to the visit, during the visit, and after the visit. We hypothesized that software tools that could help connect these three phases would be helpful and valuable supports for the visitor. To test and evaluate our hypothesis, a system called “The Museum Explorer” was built and instantiated using the collection in the Museum of Antiquities located at the University of Saskatchewan. An evaluation of the Museum Explorer was conducted. Results show that the Museum Explorer was largely successful in achieving our goals. The Museum Explorer is an integrated solution for visitors in museums across the pre-visit, visit, and post-visit phases. The Museum Explorer was designed to provide a means to connect and transfer user experience across the major phases of a museum visit. For each phase of a visitor’s experience, a set of tools was built that provides intelligent and interactive communication features. To assist visitors selecting artefacts to visit, a recommender system allows users to select a set of constraints. To better manage interactivity, features and functions were offered based on context. A study was conducted with volunteer museum visitors. Results from the study show that the Museum Explorer is a useful support. Analysis of the usage data captured by the Museum Explorer has revealed some interesting facts about users’ preferences in the domain that can be used by future researchers.

The resolution of the image is one of the main measures of image quality. Higher resolution is desired and often required in most of the applications, because higher resolution means more details in the image. The use of better image sensors and optics is an expensive and also limiting way of increasing pixel density within the image. The use of image processing methods, to obtain a high resolution image from low resolution images is a cheap and effective solution. This kind of image enhancement is called super resolution image reconstruction. This thesis focuses on the definition, implementation and analysis on well-known techniques of super resolution. The comparison and analysis are the main concerns to understand the improvements of the super resolution methods over single frame interpolation techniques. In addition, the comparison also gives us an insight to the practical uses of super resolution methods. As a result of the analysis, the critical examination of the techniques and their performance evaluation are achieved.

Virtual machines are gaining a growing importance in modern business IT infrastructure. They facilitate multiple operating system instances on one physical host, which provides more efficient use of the computing power of the physical host but increases the amount of network traffic as well. To avoid potential network congestion and prioritize link resource usage in a virtual machine system, we propose a bandwidth regulation scheme. Extensive evaluation demonstrates that this bandwidth regulation scheme is accurate and effective. In addition, we resolved a drastic performance degradation of the Open-iSCSI initiator. We thoroughly tested the performance of the Open-iSCSI initiator and three modified versions under two methods of setting the TCP send buffer size - statically and dynamically. Based on these results, we propose a performance tuning scheme, which can enable users of Open-iSCSI, especially those using Open-iSCSI over a long fat network, to achieve significant throughput gains.