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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Seismic Imaging of the Global Asthenosphere using SS Precursors

Sun, Shuyang 21 September 2023 (has links)
The asthenosphere, a weak layer beneath the rigid lithosphere, plays a fundamental role in the operation of plate tectonics and mantle convection. While this layer is often characterized by low seismic velocity and high seismic attenuation, the global structure of the asthenosphere remains poorly understood. In this dissertation, twelve years of SS precursors reflected off the top and bottom of the asthenosphere, namely, the LAB and the 220-km discontinuity, are processed to investigate the boundaries of the asthenosphere at a global scale. Finite-frequency sensitivities are used in tomography to account for wave diffraction effects that cannot be modeled in global ray-theoretical tomography. Strong SS precursors reflected off the LAB and the 220-km discontinuity are observed across the global oceans and continents. In oceanic regions, the LAB is characterized by a large velocity drop of about 12.5%, which can be explained by 1.5%-2% partial melt in the oceanic asthenosphere. The depth of the Lithosphere Asthenosphere Boundary is about 120 km, and its average depth is independent of seafloor age. This observation supports the existence of a constant-thickness plate in the global oceans. The base of the asthenosphere is imaged at a depth of about 250 km in both oceanic and continental areas, with a velocity jump of about ∼ 7% across the interface. This finding suggests that the asthenosphere in oceanic and continental regions share the same defining mechanism. The depth perturbations of the oceanic 220-km discontinuity roughly follow the seafloor age contours. The 220-km topography is smoother beneath slower-spreading seafloors while it becomes rougher beneath faster-spreading seafloors. In addition, the roughness of the 220-km discontinuity increases rapidly with spreading rate at slow spreading seafloors, whereas the increase in roughness is much slower at fast spreading seafloors. This observation indicates that the thermal and compositional structures of seafloors formed at spreading centers may have a long-lasting impact on asthenospheric convections. In continental regions, a broad correlation is observed between the 220-km discontinuity depth structure and surface tectonics. For example, the 220-km discontinuity depth is shallower along the southern border of the Eurasian plate as well as the Pacific subduction zones. However, there is no apparent correlation between 3-D seismic wavespeed in the upper mantle and the depths of the 220-km discontinuity, indicating that secular cooling has minimum impact on the base of the asthenosphere. / Doctor of Philosophy / In classic plate tectonic theory, the outermost shell of the Earth consists of a small number of rigid plates (lithosphere) moving horizontally on the mechanically weak asthenosphere. In the classic half space cooling (HSC) model, the lithosphere is formed by gradual cooling of the hot mantle. Therefore, the thickness of the plate depends on the age of the seafloor. The problem with the HSC model is that bathymetry and heat flow measurements at old seafloors do not follow its predicted age dependence. A modified theory, called plate cooling model, can better explain those geophysical observations by assuming additional heat at the base of an oceanic plate with a constant thickness of about 125 km. However, such a constant-thickness plate has not been observed in seismology. In this thesis, the asthenosphere boundaries are imaged using a global dataset of seismic waves reflected off the Earth's internal boundaries. Strong reflections from the top of the asthenosphere are observed across all major oceans. The amplitudes of the SS precursors can be explained by 1.5%-2% of partial melt in the asthenosphere. The average boundary depths are independent of seafloor age, and this observation supports the existence of a constant-thickness plate in the global oceans with a complex origin. The 220-km discontinuity, also called the Lehmann Discontinuity, was incorporated in the Preliminary Reference Earth Model in the 1980's to represent the base of the asthenosphere. However, the presence and nature of this boundary have remained controversial, particularly in the oceanic regions. In contrast to many studies which suggest the 220-km discontinuity does not exist in the global oceans, SS precursors reflected from this interface are observed across the oceanic regions in this thesis. Furthermore, there is a positive correlation between the topography of the 220-km discontinuity and seafloor spreading rate. Specifically, the 220-km discontinuity is smoother beneath slower-spreading seafloors and much rougher beneath faster-spreading seafloors. In addition, the roughness increases faster at slowerspreading seafloors while much more gradual at faster-spreading seafloors. This indicates a close connection between seafloor spreading and mantle convections in the asthenosphere, and seafloors have permanent memories of their birth places. Different melting processes at slow and fast spreading centers produce seafloors with different physical and chemical properties, modulating convections in the asthenosphere and ultimately shaping the topography of the 220-km discontinuity. Reflections from the 220-km discontinuity are also observed across the global continental regions. In addition, the 220-km discontinuity beneath the continents is comparable to that under oceanic regions in terms of their average depth (∼ 250 km) and velocity contrast across the discontinuity (∼ 7%). In continental regions, there is a general connection between the 220-km depth structure and plate tectonics. For example, the boundary is shallower along the southern border of the Eurasian plate from the Mediterranean region to East Asia where mountain belts were formed as a result of collision between the Eurasian plate and the Nubian, Arabian and Indian plates. Depth perturbations of the 220-km discontinuity are also observed along the Pacific subduction zones including the Cascadia Subduction Zone, Peru-Chile Trench and Japan-Kuril Kamchatka Trench. In addition, depth anomalies are mapped in the interior of continents, for example, along the foothills of high topography in the interior of the Eurasian plate, which may be controlled by far-field convection associated with the convergent processes at the plate boundaries.
72

Designing a knowledge management tool to support knowledge sharing networks

Barber, Kevin D., Perez-Aros, A., Munive-Hernandez, J. Eduardo, Eldrige, S. January 2007 (has links)
No / The purpose of this paper is to present a knowledge management (KM) tool which has been designed to support the creation of virtual knowledge sharing networks (KSNs). It is a software-based application that enables the sharing of knowledge related to the implementation of manufacturing excellence (ME) best practices and improvement tools. A survey of SMEs was carried out to investigate the implementation of ME best practices. The results indicated that that the main barrier to the implementation of best practices, quality models and improvement tools is a lack of knowledge about these initiatives due to the resource constraints experienced by SMEs. This led to the development of a KM tool to support the creation of virtual networks to enable SMEs to manage improvement projects and share effectively the generated knowledge. The KM tool is currently at the stage of validation and its future implementation is also under consideration. The KM tool supports the creation of KSNs through an explicit KM approach to share ideas, experiences and knowledge about implementation of best practices and improvement tools; helping SMEs to become more competitive. This research has demonstrated that is possible to provide a KM tool that is suitable for use by a KSN of SMEs. This approach allows transferring some of the tacit and explicit knowledge generated during the implementation of improvement initiatives into electronic documents for future consultation by KSN members.
73

Recherche d'haplotypes enzymatiques associés à des phénotypes métaboliques chez la tomate

Menard, Guillaume 29 November 2012 (has links)
La recherche de variations d’activités enzymatiques associées à des phénotypes chez la tomate (Solanum Lycopersicum) a permis d’apporter de nouveaux éléments pour l’étude desrelations existantes entre le métabolisme central et la qualité du fruit. Ce projet qui engageaitune nouvelle thématique au sein de l’unité Biologie et Pathologie de Fruit (UMR 1332, INRABORDEAUX) a permis dans un premier temps de développer une plateforme d’enzymologieà haut débit. Cette structure permet d’une part de réaliser plus de 10 000 déterminationsd’activités enzymatiques par jour avec une très grande reproductibilité et d’autre part dedéterminer les constantes de Michaelis (Km) apparentes pour jusqu’à une dizaine d’enzymespar jour.Dans un deuxième temps ce projet s’est attaché à étudier les relations existantes entre lesenzymes de la voie de la glycolyse chez le cultivar de tomate MicroTom. Nous y avonsrelevé l’existence de corrélations fortes entre les activités de ces enzymes. Nous avonségalement mis à jour l’existence de corrélations pour les enzymes mesurées à partir de deuxétages foliaires distincts ce qui suggère que les réseaux enzymatiques sont conservés ausein d’une plante.Dans un troisième temps, le criblage d’une collection de mutants de tomate MicroTom a étéentrepris. Ce criblage de plus de 150 familles (soit environ 1800 plantes) sur la base desactivités enzymatique de onze enzymes du métabolisme central à deux concentrations desubstrats différentes (saturante et non saturante) a abouti à l’identification de deux familles.Ces deux familles porteraient chacune une mutation affectant les caractéristiques cinétiquesde la Triose-Phosphate Isomérase. Ces mutations étaient toujours en cours d’étude à la finde ce projet. Ces résultats ouvrent de nouvelles perspectives pour la compréhension desrelations entre les enzymes du métabolisme central. Ils permettent aussi d’apporter desméthodes d’identification rapide de mutants enzymatiques au sein d’une large population. / Research on enzymatic variations associate with phenotypes in tomato (SolanumLycopersicun) provided new and original input regarding links between central metabolismand fruit quality. This project took part in a new topic of the Fruit Biology and Pathology Unit(UMR 1332, INRA BORDEAUX). First, during this project, a new high-throughputenzymology platform was created. This unique lab offers possibility to determine both morethan 10 000 enzyme activities per day with a very good reliability and apparent Michealisconstant (Km) for up to ten enzymes per day.Second, this project investigated existent relationship between glycolytic enzymes inMicroTom tomato cultivar. We highlighted strong correlations between enzymes in leaves.We also uncovered correlations between enzymes activities measured in two distinct foliarlevels. These elements suggest inheritability of the enzymes network within the plant.Third, the screen of an Ethylmethyl Sulfonate (EMS) MicroTom mutant’s collection wasinitiated. 150 families (around 1800 plants) were screened for eleven enzymes with twodifferent substrate concentrations. At the end of the process, two families were identified;both could have mutation(s) that affect(s) the kinetic characteristic of Triose-Phosphateisomerase. These mutations were style investigated at the end of this project. These originalresults provide new perspectives for knowledge of relationship between central metabolism’senzymes. Finally, This project proposes new and rapid enzymatic mutant identification withina large population as an EMS mutant’s collection.
74

Křesťanské centrum Eliáš / Christian Center Elijah

Koloničný, Libor January 2015 (has links)
The aim of this master thesis is to prepare the project documentation for a building of a Christian centre. The building is designed for liturgical purposes, but also leisure activities and consists of two floors and a partial basement. The main parts of the building: Main hall for worship services, group of rooms for activities, small hall, tea room and a dwelling unit for the pastor. The floor plan of the building is shaped like the letter „V“, and the architectural design of the building does not interfere with the landscape. The building is set in slightly sloping terrain which forms a contrast with the opposite rising flat roof over the main hall.
75

Knowledge technologies process and cultures : improving information and knowledge sharing at the Amateur Swimming Association (ASA)

Onojeharho, Ejovwoke January 2015 (has links)
Over the last few years the ASA determined KM as a priority to assist with reducing knowledge loss, realising information assets and reducing work duplication by attempting to implement IKM tools and strategies. This research employed a pragmatic viewpoint, using a mix of both quantitative and qualitative methods to check reliability, to ensure validity while undertaking the task of implementing the IKM tools. Using a case study strategy and action research was justified, as to be pragmatic the researcher needed to understand the extent of the problem within a specified context. The research discussed in this thesis, provides a new framework for implementing KM tools; focusing on the NSO category, which the case study organisation falls into. The literature agrees enlisting influential members onto the project is vital for success; however, the findings suggested that success was not only tied to this buy-in alone, but also to the organisation s ability to retain these members for the duration of the project. The research proposed the use of a newly developed tool within the new framework, as an approach to reduce the time it takes to undertake traditional social network analysis of the organisation, as it became clear that there was a need for a method of producing updated results of the SNA, which would span the length of long projects within organisations with significantly high staff turn-over rates. Privacy was given as a factor to consider the in literature; however, the findings from this study indicated that a majority of the participants were comfortable with the system. Email knowledge extraction, and email social network systems are not new concepts, however this research presents EKESNA; a novel tool that combines both concepts in a way that allows for the continuous discovery, visualisation, and analysis of knowledge networks around specified topics of interest within an organisation; linking conversations to specific expert knowledge. EKESNA s continuous discovery of the organisation s knowledge network affords members up-to-date data to inform business process reengineering. This is a potentially ground breaking new tool that has the possibility of transforming the KM landscape in NSOs as well as a whole range of other kinds of enterprises.
76

Création de nouvelles connaissances décisionnelles pour une organisation via ses ressources sociales et documentaires / Creation of new decisional knowledge for an organization by analysing its social and documentary resources

Deparis, Etienne 19 December 2013 (has links)
L'aide à la décision se fonde sur l'observation d'un environnement évolutif dont on scrute les évènements. Ces évènements peuvent être de différentes natures, dont les connexions qui peuvent se créer au sein d'un réseau d'acteurs. L'observation des bases documentaires ne semble plus suffisante pour nourrir l'aide à la décision. En effet, les nouveaux outils de communication et de collaboration, dont l'usage se répand rapidement au sein des organisations, sont sources de nouvelles formes d'informations peu ou mal utilisées par les systèmes actuels d'aide à la décision des organisations. L'objectif de la thèse est de concevoir une plate-forme (modélisation et développement) pour les organisations permettant à leurs membres de bénéficier de médias sociaux et à leurs décideurs de bénéficier d'outils d'aide à la décision prenant en compte tous les types de ressources circulant sur cette plate-forme. / Decision support is partly based on the observation of a dynamic and mutating environment (Situation Awareness). The events of such environments can be of different types, including new relations created within a network of actors. We think classical documentary databases are no longer sufficient to serve situation awarness. The quick spread and adoption of new communication and collaboration tools in organizations, bring new kind of information, like the social network of the organization, which are currently not or badly taken in account by organizational decision support systems. The aim of this thesis is to design a platform, which provides to organizations both the social media to help their members to collaborate and the decision tools, which take into account all types of information exchanged in the platform.
77

Information Technology Management Strategies to Implement Knowledge Management Systems

McGee, Mary Jane 01 January 2017 (has links)
More than 38% of the U.S. public workforce will likely retire by 2030, which may result in a labor shortage. Business leaders may adopt strategies to mitigate knowledge loss within their organizations by capturing knowledge in a knowledge management system (KMS). The purpose of this single case study was to explore strategies that information technology (IT) managers use to develop and implement a KMS. The target population consisted of IT managers in a small-sized organization located in northwestern Florida who had implemented a KMS successfully. The conceptual framework for this study was organizational knowledge creation theory. The collection of public documents, execution of semistructured interviews with 5 qualified participants, literature on the topic, and member checking formed the determination of the findings of the study. Using triangulation and coding the data for emergent themes, 6 themes emerged from the data analysis: (a) training, (b) customer focus, (c) policy and governance, (d) leadership and management support, (e) communication and marketing, and (f) business process management. The application of the findings may contribute to social change by identifying strategies that leaders and IT managers from communities and government agencies use in implementing a KMS that may facilitate transparency and open flow of information to citizens, and allow access to timely, civic, and potentially life-enhancing information.
78

Content Management System i intranät : Open Source CMS som intranät / Content Management Systems in intranet : Usage of Open Source CMS as intranet

Björnstad Pedersen, Rune January 2008 (has links)
<p>Idag har de flesta företag och organisationer någon form för intranät-lösning. Dessa lösningar kan vara både mer och mindre sofistikerade, men har oftast det samma syfte; att distribuera organisationens information till dess medlemmar.</p><p>Denna uppsats ägnar sig åt intranät och fördjupar sig i ett begrepp som vuxit starkt de senaste åren, nämligen Content Management System (CMS). Jag fokuserar särskilt på val av Open Source CMS, för implementation i mindre organisationers intranät.</p><p>Uppsatsen är ett resultat av omfattande litteraturstudier inom sitt område och bygger främst på vetenskapliga artiklar av ledande experter. Ytterligare en källa är resultatet av en enkätundersökning, som också redovisas i uppsatsen. Denna enkät hade som ändamål, att kartlägga användares attityder till deras CMS-intranät.</p><p>Uppsatsens kanske viktigaste resultat är en redogörelse för hur ett moduliserad CMS-intranät skulle kunna utformas, baserad på bl.a. Knowledge Management-teori, där tyngdpunkten ligger på de personliga referensernas betydelse för en människas tolkning av sin omgivning, och logisk kategorisering av information.</p> / <p>Today, most companies and organizations have some kind of intranet solution. These system solutions vary and tend to be either more or less sophisticated, but the overall purpose remains the same; distributing the organizations information to its members.</p><p>This essay is about intranet-development, and mainly devoted to explore a concept which has grown rapidly in recent years; Content Management System (CMS). I’m particular focusing on how to choose a suitable Open Source CMS, for implementation in a small organizations intranet.</p><p>The essay is the result of vast literature studies, mainly based on scientific articles from leading experts within their field. In addition I have also carried out a survey in a company intranet, in order to investigate the users’ attitude towards their CMS-intranet.</p><p>One of the most important results of the essay is my model of a modularized CMS-intranet, partially based on Knowledge Management-theory and the importance of appropriate references in order to interpret our surroundings, and logical categorization of information.</p>
79

The Relationship among Organizational Characteristics, Knowledge Management, Strategy of Knowledge Management, and Organizational Innovation

Tseng, Chih-Hsien 26 June 2001 (has links)
Two of the most important issues in knowledge age are knowledge management and innovation. Companies that is able to control knowledge, able to develop the ability of innovation. Therefore, understand how to acquire, encode, diffuse, storage knowledge, and how to match knowledge and management system, is very important for organizations. Knowledge workers are the most important carrier of knowledge. They are the one who actually learn, share, use, and create knowledge. Thus, understand and pay attention to knowledge worker and the management of knowledge worker should be considered one part of knowledge management. Moreover, knowledge management should match corporation¡¦s competitive strategy. The purpose of this thesis is to examine the relationship among organizational characteristics, knowledge management, strategy of knowledge management, organizational innovation, and consider the influence of the strategy of knowledge management and organizational characters to knowledge management and organizational innovation. The results of the research indicate that: The lifecycle of a company has significant difference on organizational innovation. The scale of a company has also significant difference on organizational innovation. In addition to difference analysis, relation analysis indicates that ¡§connect performance and reward¡¨, ¡¨improve knowledge which is already there¡¨, ¡§leadership of knowledge¡¨, ¡§institutionalize the measurement of knowledge¡¨, ¡§organic organization structure¡¨, and ¡§culture of learning¡¨ has significant influence on organizational innovation. As the result, the suggestions are: companies should develop their manager¡¦s ability of leadership of knowledge; connect performance and reward; improve knowledge which is already there; institutionalize the measurement of knowledge; establish organic organization structure; and create the culture of learning.
80

Study of Professional Medical Personnel's Awareness & Attitude of Knowledge Management

Huang, Yih-Sheng 19 July 2001 (has links)
In an information era of new knowledge-based economy, how should the traditional medical industry respond? Do medical professionals have any awareness of knowledge management? If yes, what is their attitude towards knowledge? What are the features? Based on the infusion methodology of knowledge management, if a hospital seeks to adopt an information system for knowledge management (KM), the hospital will have to go through the process of integrating the strategy, the process, the information technology and the awareness of the people and the organization. Subjects of this study were medical professionals, and Arthur Andersen¡¦s knowledge management model was taken as reference. The structure of the study is divided into two sections, i.e. ¡§employees¡¦ awareness of knowledge management¡¨ and ¡§employees¡¦ awareness of the hospital¡¦s knowledge management¡¨. In the former section, factor analysis reveals that medical professionals tend to view knowledge management as the planning and integration of personal knowledge management. Medical professionals recognize that knowledge is an important personal asset, and some inexpressible tacit knowledge still exists in one¡¦s knowledge that needs to be valued. Furthermore, they also believe that in order to increase the value of knowledge assets, it is necessary to share knowledge. In the latter section, factor analysis reveals that medical professionals recognize that a hospital should have a properly planned process to gain knowledge and should create an innovative and practical environment to accumulate knowledge-based assets for the hospital. As for personal property, in the section of ¡§employees¡¦ awareness of knowledge management¡¨, the study manifests obvious difference on the variables of personal property which includes scale of hospital, age, gender, working years, educational background, type of work and management post. On the other hand, the study shows that in the section of ¡§employees¡¦ awareness of the hospitals¡¦ knowledge management¡¨, there is obvious difference on the variables of personal property including scale of hospital, age, working year, educational background while the property of the gender, type of work and management post remain relatively the same. Moreover, the study also shows that if employees are more satisfied with the self-awareness of knowledge management, they are more likely to agree with every dimensions of the knowledge management of the hospital they work in. On the other hand, if all dimensions of the hospital¡¦s knowledge management are recognized by the employees, the variable of the self-awareness of knowledge management reflected on the employees will also be positive. This demonstrates that the demand of employee¡¦s personal awareness will be influenced by the working environment, and vice versa. Outstanding employees will affect the operation performance of the hospital. Similarly, a properly managed hospital will enhance the performance of the employees. It is apparent that the two are related to each other from the feature analysis of the study. Thus, if the hospital can invest in improving the structure of the knowledge assets of the hospital and enhance education and propagation, any improvement of the ability of knowledge management of either employers or employees will definitely benefit the other party. In regards to the four elements including the promotion of knowledge management, high-level leadership enterprise culture, information technology and measurement indicators, the canonical correlation analysis and the regression analysis show that the four elements have been highly approved by the medical professionals. In terms of high-level leadership, the establishment of the Chief Knowledge Office (CKO) has been applauded by the employees. At the meantime, the employees¡¦ ability of using computers and the willingness of sharing information have been greatly influenced by the culture of the enterprise. As for information technology, the information reveals the close relationship between the employees¡¦ ability of using computer and the result of the hospital performance of using the information technology. For measurement indicators, in order to make medical professionals recognize the introduction of knowledge management, performance evaluation of all phases of the introduction of knowledge management should be properly conducted. It is recommended by the study to adopt the theory of the balanced scorecard to be the measurement indicators for evaluation the practical performance of the three components of knowledge assets because the framework of both theories are quite similar. Furthermore, the study reveals that employees who have worked longer and who are older will be more likely to recogize the management of knowledge self-supervision and are more willing to share their knowledge. Apparently, when a hospital tries to introduce knowledge management to the employees, it will be more efficient and more effective if the hospital can make full use of the participation of senior employees.

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