This research explores the relationship between sense of coherence, work engagement and organisational commitment in an automotive development institution in South Africa. The study was conducted through quantitative research. The study used the Orientation to Life Questionnaire (OLQ) to measure sense of coherence, the Utrecht Work Engagement Scale (UWES) to measure work engagement and the Organisational Commitment Scale (OCS) to measure organisational commitment. A biographical questionnaire was also used. The questionnaires were administered to a sample of 46 employees, 37 of whom were based in the company’s Pretoria office and nine at their Eastern Cape office. In view of the fact that the sample was small, 100 % of the population was included in the study. A theoretical relationship between the constructs was determined and an empirical study provided evidence of the degree of relationship that existed between them. The results reveal significant relationships to exist between some sub-scales, however, statistical significance could not be reached for some correlations. / Psychology / M. Admin. (Industrial and Organisational Psychology)

Die studie foku.s op die verwantskap tussen sin vir koherensie as 'n intrinsieke hanteringsbron aan die een kant, en elk van streshantering, algemene gesondheid en sielkundige uitbranding aan die antler kant. Vraelyste wat hierdie veranderlikes meet is aan 200 bestuurders gegee om te voltooi. Die bevindinge van hierdie studie toon aan dat bestuurders met 'n hoi! sin vir koherensie goeie algemene gesondheid geniet. Die bestuurder met 'n hoi! sin vir koherensie behoon dus meer e.ffektief te junksioneer in die werksiruasie as die bestuurder met 'n lae sin vir koherensie. Voons is ook bevind dar 'n hoi! sin vir koherensie nie noodwendig aanleiding gee tot lae vlakke van stres of van sielkundige uitbranding nie. Aanbevelings word gedoen oor hoe om die negatiewe gevolge van stres en sielkundige uitbranding te venninder en algemene gesondheid te bevorder, ten einde die bestuurder se potensiaal optimaal benut. / This study focuses on the relationship between sense of coherence as an intrinsic coping mechanism. and work stress, general health and psychological burnout. To measure these variables, questionnaires were completed by 200 managers. The findings of this study indicate that managers with a high sense of coherence experience good general health. The manager with a high sense of coherence should therefore junction more efficiently in a work situation·than the manager with a low sense of coherence. It was also found that a high sense of coherence does not necessarily lead to low levels of stress nor of psychological burnout. Recommentfations are made on how to reduce the negative effects of stress and psychological burnout and how to improve general health in order to make optimal use of the manager's potential. / Industrial and Organisational Psychology / MCom (Bedryfsielkunde)

Burnout can occur in any occupation and is a risk in the modern world of work. The objective of the study was to investigate how burnout, coping and sense of coherence are related and influence each other in an engineering environment. A Cross-sectional survey design was used in this descriptive study. The convenience sample consisted of 118 engineers and scientists at various levels in a global engineering organisation that is based in South Africa. The Maslach Burnout Inventory (MBI), Coping Orientations to the Problems Experienced (COPE) and Sense of Coherence (SOC) questionnaires were administered for this quantitative study. A theoretical relationship was proved by means of a literature study and an empirical relationship proved that there is indeed a relationship between the constructs and that focus and venting of emotions as well as SOC are predictors of emotional exhaustion and cynicism. SOC also proved to be a predictor of professional efficacy. / Industrial and Organisational Psychology / M.A. (Industrial and Organisational Psychology)

The key objective of this study was to determine the relationship between burnout (measured by the Maslach Burnout Inventory – Human Services Survey (MBI-HSS)), work engagement (measured by the Utrecht Work Engagement Scale), and sense of coherence (measured by the Orientation of Life Questionnaire developed by Antonovsky (1987)). A quantitative study using a cross-sectional survey research design was conducted on a randomly selected sample (N = 178) of nurses at a central hospital in Kwa-Zulu Natal. A theoretical relationship was established between the variables. The empirical relationship revealed statistically significant negative relationship between burnout and work engagement. A statistically significant negative relationship was also established between burnout and SOC. The findings add valuable knowledge to industrial and organisational psychology and can be applied to promote employee and organisational wellness. / Industrial and Organisational Psychology / M. Com. (Industrial and Organisational Psychology)

Die studie foku.s op die verwantskap tussen sin vir koherensie as 'n intrinsieke hanteringsbron aan die een kant, en elk van streshantering, algemene gesondheid en sielkundige uitbranding aan die antler kant. Vraelyste wat hierdie veranderlikes meet is aan 200 bestuurders gegee om te voltooi. Die bevindinge van hierdie studie toon aan dat bestuurders met 'n hoi! sin vir koherensie goeie algemene gesondheid geniet. Die bestuurder met 'n hoi! sin vir koherensie behoon dus meer e.ffektief te junksioneer in die werksiruasie as die bestuurder met 'n lae sin vir koherensie. Voons is ook bevind dar 'n hoi! sin vir koherensie nie noodwendig aanleiding gee tot lae vlakke van stres of van sielkundige uitbranding nie. Aanbevelings word gedoen oor hoe om die negatiewe gevolge van stres en sielkundige uitbranding te venninder en algemene gesondheid te bevorder, ten einde die bestuurder se potensiaal optimaal benut. / This study focuses on the relationship between sense of coherence as an intrinsic coping mechanism. and work stress, general health and psychological burnout. To measure these variables, questionnaires were completed by 200 managers. The findings of this study indicate that managers with a high sense of coherence experience good general health. The manager with a high sense of coherence should therefore junction more efficiently in a work situation·than the manager with a low sense of coherence. It was also found that a high sense of coherence does not necessarily lead to low levels of stress nor of psychological burnout. Recommentfations are made on how to reduce the negative effects of stress and psychological burnout and how to improve general health in order to make optimal use of the manager's potential. / Industrial and Organisational Psychology / MCom (Bedryfsielkunde)

Background. The development of non-invasive imaging techniques has been stimulated by the shortcomings of histopathology. Currently the only valid diagnostic technique in dermatology is skin biopsy which remains a painful, invasive intervention for the patient. Moreover, this approach is not always convenient for monitoring and follow-up of a skin disease. Optical imaging technologies could solve these shortcomings as they are fast, precise, repeatable and painless. There are four established non-invasive skin imaging techniques used in daily practice: dermoscopy, high-frequency ultrasound, reflectance confocal microscopy (RCM) and conventional optical coherence tomography (C-OCT). In imaging there is a trade-off between resolution and penetration depth. The former permits the visualization of cells, if the resolution is at least 3 µm. The latter enables the recognition of patterns and structures in deeper layers of the skin if the penetration depth is deeper than 150 µm. New non-invasive techniques using infrared light sources have been developed recently. The technique used in this work is a high-definition optical coherence tomography (HD-OCT).Objectives. The overall aims of this thesis were the feasibility of HD-OCT to visualize in/ex vivo, in real time and in 3-D the cellular and structural morphology of the skin, secondly the assessment of the capability of this technology to measure in vivo and real time the cutaneous optical properties, and finally the determination of the contribution of this technique to the non-invasive near-infrared imaging technologies. Five specific objectives have been established: i) could cells be observed in their 3-D microenvironment in normal and diseased skin, ii) could we describe morphologic features of cells and structures in normal and diseased skin (m_HD-OCT), iii) could these morphologic features be quantified by optical property analysis (o_HD-OCT), iv) was it possible to perform accurate thickness measurements in normal and diseased skin, and finally v) what was the diagnostic potential of this technique?Methodology. HD-OCT uses a combination of parallel time-domain interferometry, high power tungsten lamp (with Gaussian filter, very low lateral coherence and ultra-high bandwidth (1300 nm +/- 100 nm)), and last but not least, full field illumination with real time focus tracking. A constant homogeneous resolution of 3 µm resolution in all three dimensions is obtained up to a depth of 570 µm. Hence, the system is capable of capturing real time full 3-D images. Moreover, the in vivo assessment of optical properties of the skin is only applicable to OCT when operating in focus-tracking mode, which is the case for HD-OCT. The means to obtain answers to the five specific questions were the comparison of en face HD-OCT images with RCM and HD-OCT cross-sectional images with histopathology and C-OCT. Results. At least 160 line pares were observed by imaging a high resolution phantom with HD-OCT. This suggested a 3 µm lateral resolution. The presence of cells such as keratinocytes, melanocytes, inflammatory cells, fibroblasts and melanophages in their 3-D cutaneous microenvironment in vivo as well as ex vivo has been demonstrated .A qualitative description of structures and patterns in normal and diseased skin could be performed by HD-OCT. Clear structural changes of the epidermis, dermo-epidermal junction, papillary dermis and reticular dermis related to intrinsic skin ageing could be observed. Lobulated structures, surrounded by stretched stromal fibers and arborizing vessels, could be demonstrated in nodular basal cell carcinoma (BCC). The o_HD-OCT of normal and diseased skin could be assessed in vivo. This approach permitted the quantitative assessment of the OCT signal attenuation profiles of normal healthy skin, actinic keratosis (AK) and squamous cell carcinoma (SCC). Differences in signal attenuation profiles could be demonstrated between these three groups. These differences were also observed between BCC subtypes. The slope of the exponential attenuation of the signal in the upper part of the epidermis was very high in benign nevi. The more malignant the lesion the lower the slope. Thickness measurements of epidermis and papillary dermis could be performed by m_HD-OCT, based on a cross-sectional images and their corresponding en face image. More accurate measurements of epidermal and papillary dermal thickness could be performed based on the optical analysis of a skin volume by o_HD-OCT. The diagnostic potential of HD-OCT in comparison with dermoscopy, RCM and C-OCT could be assessed regarding i) melanoma, ii) BCC differentiation from BCC imitators and BCC sub-differentiation and iii) SCC differentiation from AK. A much higher diagnostic potential could be demonstrated for o_HD-OCT in comparison with m_HD-OCT concerning melanoma detection. The diagnostic potential of HD-OCT to discriminate BCC from clinical BCC imitators was moderate. However, HD-OCT seemed to have high potential in sub-differentiation of BCC subtypes: i) it seemed to be the best technique to include and exclude a superficial BCC, ii) the technique appeared to be the best approach to exclude nodular BCC, and iii) HD-OCT looked to be the best technique to include an infiltrative BCC. Finally, HD-OCT has proven to be a powerful method to discriminate AK from SCC.Conclusions. HD-OCT is able to capture real time 3-D imaging with a sufficiently high optical resolution and penetration depth to allow the visualization of cells in and ex vivo in their micro-architectural context. At the same time, HD-OCT permits the recognition of patterns and structures in a sufficiently large volume of skin (1.5 mm³). HD-OCT closes therefore the gap between RCM with a high resolution but low penetration depth and C-OCT with a low resolution but high penetration depth. Moreover, HD-OCT permits, in contrast to RCM and C-OCT, the real time in vivo analysis of optical properties of the skin. HD-OCT seems to be a promising tool for early diagnosis of melanoma, BCC sub-differentiation and differentiation between SCC and AK.Future perspectives. Multicenter validation studies are needed to determine the diagnostic performance of this promising new technology, especially in other clinical settings combining both morphological and optical property analysis. This combined analysis could be a valuable method not only for diagnosis, monitoring and therapeutic guidance of dermatologic diseases but it could also be helpful in the management of non-dermatologic conditions such as diabetic micro-angiopathy, infantile cystinosis or even osteoporosis. / Doctorat en Sciences médicales (Santé Publique) / info:eu-repo/semantics/nonPublished

Les travaux développés dans ce manuscrit de thèse concernent la proposition et la mise au point d’une nouvelle architecture optique basée sur la modulation de cohérence (MC) d’une source à spectre large dédiée aux calculs arithmétiques et au traitement des signaux. La modulation de cohérence de lumière est une technique particulière de codage optique qui autorise, entre autres, le multiplexage des signaux à travers une seule porteuse. Les signaux à traiter sont codés en MC par le biais de paires modulateur de lumière/lame de phase placées en série et éclairées par un seul faisceau de lumière polarisée. Cette technique est basée sur l’introduction d’un retard optique supérieur à la longueur de cohérence de la source utilisée. La validation expérimentale de l’approche proposée pour la réalisation d’opérations arithmétiques, telles que la somme et la soustraction, a été effectuée par le biais de signaux temporels. Différentes formes et fréquences des signaux ont été testées et ont parfaitement validé l’approche. L’impact du cross-talk des signaux et de la divergence du faisceau gaussien sur la qualité des opérations effectuées a été étudié. Ces effets se traduisent par un bruit de modulation d’intensité affectant le résultat des opérations effectuées. Dans ce travail, nous avons proposé des solutions permettant de minimiser son impact. L’originalité de la technique proposée est qu’elle permet la réalisation d’opérations multiples entre plusieurs signaux. Des tests ont été réalisés sur des images à deux et plusieurs niveaux de gris. Les résultats obtenus ont été évalués par les figures de mérite incluant le rapport signal sur bruit (SNR, signal to noise ratio), le rapport signal/bruit crête à crête (PSNR, peak signal to noise ratio) et l’erreur quadratique moyenne (MSE, mean squared error). Enfin, nous avons appliqué la technique à la cryptographie par contenu. Nous avons démontré la performance et la robustesse de la technique. Comme perspectives de ce travail, nous envisageons exploiter d’avantage la technique dans le domaine de la cryptographie (ie: utilisation d’une phase aléatoire pour le codage des images). De plus, une extension de l’étude à la compression des images sera utile. Une autre perspective de ce travail de recherche est l’étude de l’impact de l’incohérence spatiale sur le codage et le décodage des signaux / In this thesis, we study and developed the use of coherence multiplexing (also called path-difference, by analogy with WDM optical communications) to achieve simultaneous coding and decoding of analogue signals. The coherence modulation of light consists in encoding a signal on a light beam as an optical path-difference larger than its coherence length. This opens the way to the use of broadband sources in systems that thought to be restricted to quasi-monochromatic light. The different signals to be processed are encoded by using an Electro-optic Modulator and a birefringent plate placed between two polarizers. First, we have shown how the coherence multiplexing process can be exploited to achieve parallel real-time all optical signal addition and subtraction. Then, we have studied the impact of the crosstalk, due to the imperfection of the opto-geometrical parameters of the elements in the architecture, in the quality of the obtained results. The second part of the work consists of the validation of the technique to image signals. Thus, we have tested both image with binary and several gray levels. Also, we have confirmed that the method can be used for simple and multiplex encoding module. After that, we have evaluated the performance of the processor as a function of the continuous optical path-difference ratio in terms of Signal to Noise Ratio (SNR), Mean Square Error (MSE) and Peak to peak Signal to Noise Ratio (PSNR). Finally, we have tested the coherence multiplexing method to the encryption method based on merging together multiple-images. Therefore, we have evaluated the performance and the robustness of the method

Cette thèse traite de l’étude et du développement d’un système d’optique adaptative pour la tomographie par cohérence optique plein champ (AO-FFOCT en anglais) appliquée à l’imagerie haute résolution de la rétine. L’analyse de l’effet des aberrations géométriques sur les performances en FFOCT a montré que pour une illumination spatialement incohérente, la résolution transverse est insensible aux aberrations et ne fait que diminuer le niveau du signal. Comme ce sont des aberrations de bas ordres comme la myopie et l’astigmatisme qui prédominent pour l’œil humain, une méthode d’optique adaptative avec une configuration sans conjugaison qui utilise une correction de front d’onde en transmission est suggérée, puis appliquée à la correction de ces ordres afin de simplifier le système d’AO-FFOCT. Des corrections de front d’onde sont effectuées sans analyseur de surface d’onde, en utilisant le niveau du signal de FFOCT comme métrique. Des expériences avec des échantillons diffusants et un œil artificiel sont menées pour démontrer la faisabilité d’un système d’AO-FFOCT conçu pour la correction d’aberration. Afin de résoudre les problèmes posés par les mouvements oculaires et de compenser en temps réel la différence de chemin optique entre les deux bras de l’interféromètre, l’instrument de FFOCT est couplé à un système d’OCT spectral. Avec cette combinaison de systèmes, l’imagerie FFOCT in vivo cellulaire de la rétine à haute résolution a été réalisée pour la première fois sur l’œil humain. / This thesis follows the study and development of an adaptive optics full-field optical coherence tomography (AO-FFOCT) system, aiming for high resolution en face human retinal imaging. During the quantification of the effects of geometrical aberrations on the FFOCT system performance, it is shown that, with spatially incoherent illumination, the lateral resolution of FFOCT is insensitive to aberrations, which only cause the FFOCT signal reduction. Since low order aberrations like myopia and astigmatism dominate in human eye, a non-conjugate AO configuration by using transmissive wavefront corrector is suggested and applied for low order aberrations correction to simplify the AO-FFOCT system. Wavefront corrections are done with a wavefront sensorless method by using FFOCT signal level as the metric. Experiments with scattering samples and artificial eye model are conducted to demonstrate the feasibility of the customized AO-FFOCT system for aberration correction. In order to resolve the eye motion effects and employ real-time matching of the optical path lengths of the two interferometric arms in FFOCT, a system combination of traditional spectral-domain OCT (SDOCT) with FFOCT is adopted. With this combined system, high resolution FFOCT cellular retinal imaging is achieved in human eye in vivo for the first time.

<p>Plentiful research has addressed low-complexity software-based shared-memory systems since the idea was first introduced more than two decades ago. However, software-coherent systems have not been very successful in the commercial marketplace. We believe there are two main reasons for this: lack of performance and/or lack of binary compatibility.</p><p>This thesis studies multiple aspects of how to design future binary-compatible high-performance scalable shared-memory servers while keeping the hardware complexity at a minimum. It starts with a software-based distributed shared-memory system relying on no specific hardware support and gradually moves towards architectures with simple hardware support.</p><p>The evaluation is made in a modern chip-multiprocessor environment with both high-performance compute workloads and commercial applications. It shows that implementing the coherence-violation detection in hardware while solving the interchip coherence in software allows for high-performing binary-compatible systems with very low hardware complexity. Our second-generation hardware-software hybrid performs on par with, and often better than, traditional hardware-only designs.</p><p>Based on our results, we conclude that it is not only possible to design simple systems while maintaining performance and the binary-compatibility envelope, it is often possible to get better performance than in traditional and more complex designs.</p><p>We also explore two new techniques for evaluating a new shared-memory design throughout this work: adjustable simulation fidelity and statistical multiprocessor cache modeling.</p>

Thesis (Ph.D. (Industrial Psychology))--North-West University, Vaal Triangle Campus, 2007.