Global ETD Search

211	Printing quality assessment by image processing and color prediction models / Évaluation de la qualité d'impression par traitement d'images et modèles de prédiction couleur Nébouy, David 16 December 2015 (has links) L'impression, bien qu'étant une technique ancienne pour la coloration de surfaces, a connu un progrès considérable ces dernières années essentiellement grâce à la révolution du numérique. Les professionnels souhaitant remplir les exigences en termes de qualité du rendu visuel de leurs clients veulent donc savoir dans quelle mesure des observateurs humains sont sensibles à la dégradation d'une image. De telles questions concernant la qualité perçue d'une image reproduite peuvent être séparées en deux sujets différents: La qualité de l'impression, comme la capacité d'un système d'impression à reproduire fidèlement l'image d'origine, et la qualité d'une image imprimée, résultant à la fois de la qualité de reproduction, mais aussi de la qualité même de l'image numérique d'origine. Ce premier concept repose sur une analyse physique de la façon dont l'image d'origine est dégradée lors de son transfert sur un support, et nous proposons de la coupler avec une analyse sensorielle, visant à évaluer des attributs perceptuels et leur donner une valeur sur une certaine échelle, déterminée par des échantillons de référence classés par un ensemble d'observateurs. Le second concept inclut cette dégradation due à l’impression mais aussi la qualité perçu de l’image d’origine, qui ne fait pas parti de notre étude. Notre approche consiste d'abord à définir les différents indices de qualité, basés sur des critères mesurables en utilisant des outils d'évaluation basés sur des algorithmes "objectifs" de traitement d'image et des modèles optiques, sur une image imprimée-scannée. Thèse réalisée au Laboratoire Hubert Curien / Printing, though an old technique for surface coloration, considerably progressed these last decades especially thanks to the digital revolution. Professionals who want to meet the demands in terms of quality regarding the visual rendering of their clients thus want to know to which extent human observers are sensitive to the degradation of an image. Such questions regarding the perceived quality of a reproduced image can be split into two different topics: the printing quality as capacity of a printing system of accurately reproduce an original digital image, and the printed image quality which results from both the reproduction quality and the quality of the original image itself. The first concept relies on physical analysis of the way the original image is deteriorated when transferred onto the support, and we propose to couple it with a sensorial analysis, which aims at assessing perceptual attributes by giving them a value on a certain scale, determined with respect to reference samples classified by a set of observers. The second concept includes the degradation due to the printing plus the perceived quality of the original image, not in the scope of this work. In this report, we focus on the printing quality concept. Our approach first consists in the definition of several printing quality indices, based on measurable criteria using assessment tools based on “objective” image processing algorithms and optical models on a printed-then-scanned image. PhD work made in Hubert Curien Laboratory Indice de qualité Attribut de qualité Uniformité Finesse des contours Système visuel humain Apparence Scanner Technologies d'impression couleur Réflexion Couleur Reproduction d'image Print quality assessment Quality index Quality attributes Uniformity Edge sharpness Human Visual System Appearance Scanner Color printing technologies Reflection Color Image reproduction
212	Innovative Tessellation Algorithm for Generating More Uniform Temperature Distribution in the Powder-bed Fusion Process Maleki Pour, Ehsan 12 1900 (has links) Purdue School of Engineering and Technology, Indianapolis / Powder Bed Fusion Additive Manufacturing enables the fabrication of metal parts with complex geometry and elaborates internal features, the simplification of the assembly process, and the reduction of development time. However, the lack of consistent quality hinders its tremendous potential for widespread application in industry. This limits its ability as a viable manufacturing process particularly in the aerospace and medical industries where high quality and repeatability are critical. A variety of defects, which may be initiated during the powder-bed fusion additive manufacturing process, compromise the repeatability, precision, and resulting mechanical properties of the final part. The literature review shows that a non-uniform temperature distribution throughout fabricated layers is a significant source of the majority of thermal defects. Therefore, the work introduces an online thermography methodology to study temperature distribution, thermal evolution, and thermal specifications of the fabricated layers in powder-bed fusion process or any other thermal inherent AM process. This methodology utilizes infrared technique and segmentation image processing to extract the required data about temperature distribution and HAZs of the layer under fabrication. We conducted some primary experiments in the FDM process to leverage the thermography technique and achieve a certain insight to be able to propose a technique to generate a more uniform temperature distribution. These experiments lead to proposing an innovative chessboard scanning strategy called tessellation algorithm, which can generate more uniform temperature distribution and diminish the layer warpage consequently especially throughout the layers with either geometry that is more complex or poses relatively longer dimensions. In the next step, this work develops a new technique in ABAQUS to verify the proposed scanning strategy. This technique simulates temperature distribution throughout a layer printed by chessboard printing patterns in powder-bed fusion process in a fraction of the time taken by current methods in the literature. This technique compares the temperature distribution throughout a designed layer printed by three presented chessboard-scanning patterns, namely, rastering pattern, helical pattern, and tessellation pattern. The results confirm that the tessellation pattern generates more uniform temperature distribution compared with the other two patterns. Further research is in progress to leverage the thermography methodology to verify the simulation technique. It is also pursuing a hybrid closed-loop online monitoring and control methodology, which bases on the introduced tessellation algorithm and online thermography in this work and Artificial Neural Networking (ANN) to generate the most possible uniform temperature distribution within a safe temperature range layer-by-layer. Additive Manufacturing (AM) Metal Printing Selective Laser Sintering (SLS) Direct Metal Laser Sintering (DMLS) Powder-bed Fusion Process Online Morning (OM) Process Parameters Process Defects Contributing Parameters Process Signature Temperature Distribution Thermography Tessellation Algorithm Finite Element Simulation Temperature Uniformity Artificial Neural Networking (ANN) Hybrid Control
213	Evaluation of a Novel Reconstruction Framework for Gamma Knife Cone-Beam CT - The Impact of Scatter Correction and Noise Filtering on Image Quality and Co-registration Accuracy / Utvärdering av nytt rekonstruktionsramverk för Cone-Beam CT på Gammakniven - Effekten av spridningskorrigering och brusfiltrering på bildkvalitet och noggrannhet av co-registrering Hägnestrand, Ida January 2023 (has links) The Gamma Knife is a non-invasive stereotactic radiosurgery system used for treatments of deep targets in the brain. Accurate patient positioning is needed for precise radiation delivery to the target. The two latest versions of the Gamma Knife allow fractionated treatment by co-registering Cone-beam computed tomography (CBCT) images of the patient's position in the Gamma Knife with a diagnostic magnetic resonance (MR) image used for treatment planning. However, CBCT images often suffer from artifacts that degrade image quality, which may result in less accurate co-registration. This thesis project investigates the potential of a new reconstruction framework developed by Elekta, which incorporates scattering correction and noise filters, for the reconstruction of Gamma Knife CBCT images. The performance of the new reconstruction framework, along with its noise filter and scatter correction, is quantified using image quality metrics of phantoms, including contrast, uniformity, spatial resolution, and CT-number accuracy. Additionally, brain CBCT images of five patients are co-registered with their diagnostic MR images, and the mean target registration error is measured. The results indicate that the new reconstruction framework, without using scatter correction and noise filtering, performs equally well as the current framework in reconstructing Gamma Knife CBCT images, as it achieved similar image quality and co-registration accuracy. However, when the scatter correction was used, there were improvements in image uniformity and CT-number accuracy without compromising spatial resolution. Additionally, the introduction of a noise filter resulted in an improved contrast-to-noise ratio and low contrast visibility with minimal compromise of spatial resolution. Despite these image quality enhancements, there were no consistent improvements in co-registration accuracy, indicating that the co-registration is not sensitive to scatter or noise artefacts. / Gammakniven är en medicinteknisk apparat som används för icke-invasiv stereotaktisk strålkirurgi vid behandling av djupa mål i hjärnan. För att uppnå precision i strålbehandlingen krävs noggrann patientpositionering. De två senaste versionerna av Gammakniven tillåter fraktionerad behandling genom att co-registrera cone-beam computed tomography (CBCT)-bilder av patientens position i Gammakniven med en diagnostisk magnetresonans (MR)-bild som används för behandlingsplanering. Tyvärr lider CBCT-bilder ofta av artefakter som kan försämra bildkvaliteten och därmed minska precisionen i co-registreringen. Detta examensarbete undersöker ett nytt rekonstruktionsramverk som utvecklats av Elekta. Det nya rekonstruktionsramverket och dess tillhörande brusfilter och spridningskorrigering utvärderas för rekonstruktion av Gammaknivens CBCT bilder med hjälp av bildkvalitetsmått för fantomer, såsom kontrast, uniformitet, spatial upplösning och noggrannhet i CT-nummer. Dessutom co-registreras CBCT-bilder från fem patienter med deras diagnostiska MR-bilder, och det genomsnittliga registreringsfelet mäts. Resultaten visar att det nya rekonstruktionsramverket, utan användning av spridningskorrigering och brusfiltrering, presterar lika bra som det nuvarande ramverket för rekonstruktion av CBCT-bilder från Gammakniven. Båda ramverken ger liknande bildkvalitet och noggrannhet i co-registreringen av bilderna. Vid användning av spridningskorrigering observerades förbättringar i uniformiteten och noggrannheten i CT-nummer utan att den spatiala upplösningen försämrades. Införandet av brusfilter resulterade i ett förbättrat kontrast-brus-förhållande och synlighet av svaga kontrastskillnader med endast lite avkall på den spatiala upplösningen. Trots dessa förbättringar i bildkvaliteten observerades ingen konsekvent förbättring av noggrannheten i co-registreringen av bilderna, vilket tyder på att co-registreringen inte påverkas av spridnings- eller brusartefakter i stor utsträckning. Gamma Knife Cone-beam computed tomography Image quality Image reconstruction Co-registration Contrast Uniformity Spatial resolution Scatter correction Wiener filter Noise filter Patient positioning Stereotactic radiosurgery Gammakniv Strålkniv Cone-Beam Computed Tomography Bildkvalitet Bildrekonstruktion Co-registrering Kontrast Uniformitet Spatial upplösning Spridningskorrigering Wienerfilter Brusfilter Stereotaktisk strålkirurgi Physical Sciences Fysik
214	The feasibility of the statement of generally accepted accounting practice for small and medium enterprises / Daniël Petrus Schutte Schutte, Daniël Petrus January 2011 (has links) Governments are becoming increasingly aware of SMEs as economical role players. As a result many initiatives were introduced to address the unique challenges of the SME sector. One of these initiatives was the introduction of a global accounting framework for SMEs by the International Accounting Standards Board entitled the IFRS for SMEs. South Africa became the first country to formally adopt the contents thereof as the Statement of GAAP for SMEs. The adoption of a formal accounting framework by SMEs is however challenged by, amongst other factors, the informal nature of SMEs, limited global focus, the involvement of owner–managers and different classifications of SMEs worldwide. Owing to these unique attributes it is possible that SMEs have alternative informational needs and as a result the impact of environmental factors on the adoption of the Statement of GAAP for SMEs was considered. Culture is considered the most important environmental factor affecting the accounting environment. The Value Survey Model of Hofstede was utilised to determine cultural dimensions of accounting students (n = 301) in South Africa and the United Kingdom (UK). The cultural dimensions were extended to the accounting values of Gray after which a distinct set of accounting values was identified for i) the adoption of formal, global and prescriptive accounting standards, ii) based on principles iii) by an informal SME sector. The results also revealed distinct cultural differences within South Africa as well as between South Africa and the UK. Thereafter the contents of the Statement of GAAP for SMEs/IFRS for SMEs were evaluated against reporting practices of the SME sector in South Africa. Firstly, an assessment of the contents was conducted amongst SME accountants (n = 157) using a five–point Likert–type scale. Secondly, financial statements compiled by the SME sector in South Africa were analysed to determine the relevance of the contents of the illustrative financial statements contained in the Statement of GAAP for SMEs. The analysis entailed a consolidation of a sample of SME financial statements from South Africa (n = 100). The study revealed that the accounting environment of the SME sector is affected by a wide range of environmental and related factors. These factors were summarised and discussed and recommendations for future research were made. / Thesis (Ph.D. (Accounting))--North-West University, Potchefstroom Campus, 2011. Accounting values Accounting practices Collectivism Conservatism Cultural dimensions Environmental factors Feminity Flexibility Illustrative financial statements Individualism International Accounting Standards Board Masculinity Optimism Power distance Professionalism Secrecy Small and medium entities Statutory control Transparency Uncertainty avoidance Uniformity Rekeningkundige waardes Rekeningkundige praktyke Kollektivisme Konservatisme Kultuurdimensies Omgewingsfaktore Vroulikheid Fleksibiliteit Illustrerende finansiële state Individualisme Manlikheid Optimisme Magsafstand Professionalisme Geheimhouding Klein en medium entiteite Statutêre beheer Deursigtigheid Onsekerheidsvermyding Eenvormigheid
215	The feasibility of the statement of generally accepted accounting practice for small and medium enterprises / Daniël Petrus Schutte Schutte, Daniël Petrus January 2011 (has links) Governments are becoming increasingly aware of SMEs as economical role players. As a result many initiatives were introduced to address the unique challenges of the SME sector. One of these initiatives was the introduction of a global accounting framework for SMEs by the International Accounting Standards Board entitled the IFRS for SMEs. South Africa became the first country to formally adopt the contents thereof as the Statement of GAAP for SMEs. The adoption of a formal accounting framework by SMEs is however challenged by, amongst other factors, the informal nature of SMEs, limited global focus, the involvement of owner–managers and different classifications of SMEs worldwide. Owing to these unique attributes it is possible that SMEs have alternative informational needs and as a result the impact of environmental factors on the adoption of the Statement of GAAP for SMEs was considered. Culture is considered the most important environmental factor affecting the accounting environment. The Value Survey Model of Hofstede was utilised to determine cultural dimensions of accounting students (n = 301) in South Africa and the United Kingdom (UK). The cultural dimensions were extended to the accounting values of Gray after which a distinct set of accounting values was identified for i) the adoption of formal, global and prescriptive accounting standards, ii) based on principles iii) by an informal SME sector. The results also revealed distinct cultural differences within South Africa as well as between South Africa and the UK. Thereafter the contents of the Statement of GAAP for SMEs/IFRS for SMEs were evaluated against reporting practices of the SME sector in South Africa. Firstly, an assessment of the contents was conducted amongst SME accountants (n = 157) using a five–point Likert–type scale. Secondly, financial statements compiled by the SME sector in South Africa were analysed to determine the relevance of the contents of the illustrative financial statements contained in the Statement of GAAP for SMEs. The analysis entailed a consolidation of a sample of SME financial statements from South Africa (n = 100). The study revealed that the accounting environment of the SME sector is affected by a wide range of environmental and related factors. These factors were summarised and discussed and recommendations for future research were made. / Thesis (Ph.D. (Accounting))--North-West University, Potchefstroom Campus, 2011. Accounting values Accounting practices Collectivism Conservatism Cultural dimensions Environmental factors Feminity Flexibility Illustrative financial statements Individualism International Accounting Standards Board Masculinity Optimism Power distance Professionalism Secrecy Small and medium entities Statutory control Transparency Uncertainty avoidance Uniformity Rekeningkundige waardes Rekeningkundige praktyke Kollektivisme Konservatisme Kultuurdimensies Omgewingsfaktore Vroulikheid Fleksibiliteit Illustrerende finansiële state Individualisme Manlikheid Optimisme Magsafstand Professionalisme Geheimhouding Klein en medium entiteite Statutêre beheer Deursigtigheid Onsekerheidsvermyding Eenvormigheid
216	Návrh zavedení štíhlé výroby v průmyslovém podniku / The proposal of lean production implementation in a industrial enterprise Nachtmann, Pavel January 2009 (has links) This master´s thesis describes the production process in Japanese enterprise Daikin Device Czech Republic s.r.o. with emphasis on the production schedule, equipment and manufacturing system with elements of lean production. According to the production process analysis at the given production line a new solution of the production process has been suggested to increase production efficiency. This conception has been implemented and compared to the production process before, as well as to the assumed production process after increasing the efficiency.
217	Recepce «germánského chorálního dialektu» v první polovině 20. století / The reception of the german dialect of the gregorian chant between 1900 an aprox. 1950 Zimmer, Markus January 2021 (has links) The reception of the german dialect of the gregorian chant between 1900 an aprox. 1950 (Abstract) In today's musicology, the germanic chant dialect («germanischer Choraldialekt») ist nearly unimportant. Especially in the first half of the 20th century, it was very different. In particular, the invention of the term by Peter Wagner of Fribourg in 1925 promoted the perception of a melodic phenomenon, which can be found equally in many sources of plain chant in central europe. The oldest witnesses of the phenomenon are adiastematic sources, the youngest ones were restored, restituted or newly composed in the first half of the 20th century. So this tradition is existing for more than 1000 years. The present work examines how this tradition has been scientifically, historically and practically elaborated in the last century. The chapter on the history of research shows that the phenomenon of the germanic chant dialect was still considered a local tradition of individual dioceses or monasteries in the 19th century. Michael Hermesdorff from Trier was the first to recognize striking similarities between these fragmented traditions; his pupil Peter Wagner founded the basics of the scientific research. Not all musicologists agreed with Wagner's findings and explanations, but his term and his theory prevailed. In the...
218	The "Equalizer" Administration: Managerial Strategies in the Public Sector Cavalcanti, Bianor Scelza 08 April 2005 (has links) The purpose of this dissertation is to understand the managerial "action" of public administrators in the management of their organizations within the Brazilian context. The research seeks to understand the relationships between managers and formal management mechanisms by exploring the complementary nature of the effective managerial action in the face of structural deficiencies and flaws, considering the possibility of overcoming the structuralism-subjectivism dichotomy present in the construction of the Theory of Organizations. Initially, the study provides a review of the literature on organizational design. It highlights the "goodness of fit" proposition on strategic choice issues concerning the main organizational variables design and organizational goal attainment. It also calls special attention to the emerging interest of designing theorists on interpretivist approaches to the matter, such that of Karl Weick. A review of the the administrative reforms in Brazil is made from the perspective of the main stream organizational design conceptual framework. It highlights the complex dynamics of a constant search for differentiation and flexibilization subject to patterns of advances and reversals, due to the centrality, strength and pervasiveness of the bureaucratic model. It is concluded that in no single given moment, a public manager and his team, may count on a formal organizational design which attends the"congruency" criteria, devised by organizational design conceptual frameworks, to explain organizational results in different environmental sets. Although this conclusion may explain failure at the public sector, it can not provide understanding on the many instances of significative success attained by government operations in spite of inadequate formal administrative structures. This point calls for a better understanding from the interpretivist approach, on how public administrators, strongly associated with good organizational results, engage into transformative action, in order to superate administrative structures flaws and dysfunctional cultural patterns of conduct, structurally present and constantly reproduced, in vigorous developing countries, such as Brazil. The dissertation transcribes the testimony of four outstanding public administrators, doing a deep incursion in the managerial real world of public administration, as subjectively defined by them and transformed by their engagement into action.Through the thematic version of the Oral History methodology, full segments of the complete interviews are categorized into the thirty two managerial strategies captured which are presented on a recategorized manner under eight main strategies: (1) Interchanging Frames of Reference; (2) Exploring the Formal Limits; (3) Playing the Bureaucracy Game; (4) Inducing the Inclusion of Others (5)Promoting Internal Cohesion; (6) Creating Shields against Transgressions; (7) Overcoming Internal Restrictions; (8) Letting the Structures Blossom. Each one of these eight blocks of strategies presented, deserves further reflexive interpretation by the author, on the light of the interpretivist approach to organizational design. A final effort is made, now on theory building, for improving understanding on the matter. In order to find a significant meaning underlining all the strategies extracted from the "practical consciousness" of the interviewers as revealed in their report, the author resort to a metaphor. This metaphor helps to: (1) better describe and understand a not adequately treated phenomenon, namely, good results under inadequate structural social and organizational conditions; (2) reveal the logic and the meaning underlining all the strategies adopted to generate results under these unfaithful conditions; (3) name, accordingly to the nature of the managerial transformative social action involved, an open ended class of managerial interventions of a pragmatic sort driven by an ethics of results much common to good managers, that is, the concept of "managerial equalization"; and (4) give back to public administrators, represented by the interviewees, to be incorporated in their "discursive consciousness", something the most effective and experienced public managers already have as tacit knowledge built in their "practical consciousness", and so, help the education and development of new talents. / Ph. D. equalizer manager equalizing management unfaithfull structural conditions metaphor discursive cousciousness discourse practical cosciousness tacit knowledge agency intentionality ethics empirical bases improvising equalizing theory building meaning agent desining patrimonialism reflexive interpretation organizing inclusion cohesion transgression corruption clientelism nepotism cognitive maps deponents frames of reference transformative action explanation understanding oral history flexbilization decentralization uniformity conceptual frameworks organizational change goodness of fit organizational results organizational performance differentiation uncertainty Brazil develloping countries administrative reform bureaucratic model centralization organizational design organizational theory interpretivist approach subjectivism funcionalism paradigms cultural patterns reproduction structural flaws public manager public administrator formal management mechanisms Action managerial action public administration and management public sector public policy public programs

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