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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.
41

Hledání korelátů změn tepové frekvence v fMRI datech / Correlates finding of heart rate changes in fMRI data

Jurečková, Kateřina January 2017 (has links)
This master’s thesis deals with problematic of correlates finding of heart rate changes in fMRI data. The first part describes principle of fMRI, creation of BOLD signal, data acquisition, their pre-processing and analysis. The next part describes heart rate variability and its impact on fMRI data. The following section is dedicated to pre-processing of heart rate time series to the form, which can be used in correlates finding of heart rate variability and fMRI data with generalized linear model. The process of statistical testing and its result with discussion can be found in the last part of this thesis.
42

A comparative analysis of two land reform models, the Mashishimale farm management model and the Nkumbuleni strategic partnership model, South Africa

Sekgota, Mpolaeng Gilbert 24 May 2013 (has links)
The Sustainable Restitution Support – South Africa (SRS-SA) program aimed at the development of a post-settlement support model that could be used to support beneficiaries of land reform in South Africa, especially those who received the land through restitution. The two land restitution claims were identified namely Mashishimale in the Limpopo Province and Nkumbuleni in KwaZulu Natal Province in South Africa. The main objective of the study is to determine the essential elements of two post-settlement support models to successfully implement and manage land reform projects in a sustainable manner namely: Mashishimale Farm Management Model (FMM) and Nkumbuleni Strategic Partnership Model (SPM). The data was collected through meetings and interviews with different stakeholders or role players. “Farm management can be described as the rational decision-making to achieve the objectives of the particular farming enterprise” (Van Reenen and Marais, 1992: 2). The Community Property Association (CPA) with the support of the Mashishimale community and the Tribal Authority decided to manage the farm by themselves and appointed a knowledgeable and skillful CEO and managers to manage the farm. The Mashishimale Farm Management Model has a definite management structure that is responsible for various activities on the farm. The management structure consists of a CEO, six (6) managers and two (2) assistant managers. Three steering committees were established to help in the decision-making processes. The Oxford dictionary (1979) defines partner as “person associated with others in business of which he shares risks and profits.” Nkumbuleni Community Trust (CT) has appointed a Strategic Partner and form the Nkumbuleni Strategic Partnership Model. Nkumbileni CT together with the Strategic Partner formed a company consisting of five (5) Directors aimed to manage the farm as a business. The Mashishimale CPA and Nkumbuleni CT were assisted by specialists from the University of Pretoria to develop the Interim Business Plan for the farms. The specialists from the University of Pretoria together with the Strategic Partner, CT and Project facilitator/coordinator developed a Financial Plan for Nkumbuleni CT. The specialists, the CPA and Project facilitator/coordinator further developed a Financial Plan for Mashishimale CPA. No funds were available for the FMM to manage the farm. At the SPM, the Strategic Partner made funds available to manage the farm. Both farming enterprises applied for financial assistance from CASP but didn’t receive anything. FMM and SPM received training that was developed by the SRS-SA specialists and facilitated by Project facilitator/coordinator. The Limpopo Department of Agriculture is not visible at Mashishimale and as such the roles of local municipality and extension officers are non-existence. There is no a single extension officer that the CPA knows at this juncture. The Nkumbuleni CT members are uncertain about the role of the division of Agricultural extension (Provincial Department of Agriculture and Conservation, KwaZulu Natal) can play to support them because they only attend meetings but there is nothing from them or from their Department. Both FMM (CPA) and SPM (CT) are getting advisory and other support from the private sector and other stakeholders. The Transvaal Suiker Beperk (TSB) entered into a partnership with the Trusts of Siphumelele Community and Ingwenyama Community (separately) through its Agricultural services company known as Shubombo Agricultural Services (Chiyoka, 2009). Strategic Partnership Model has a definite management structure. Extension services are rendered in a joint venture whereby the TSB extension officials and the Provincial Department of Agriculture, Rural Development and Land Administration extension officials work together to assist farmers. The South African Sugar Association is providing technical advices on production and other relevant aspects such as market trends, etc. TSB provides training on leadership, conflict resolution management and finance management, while extension managers and production managers provide mentorship to the trustees. The Business Plans, Financial Plans and Work Skills Plans were developed by TSB (TSB, 2009). Training is regarded as part of a developmental program that is aiming at building capacity on trustees and other beneficiaries. There is well developed communication policy which outlines the possible communication strategy. A comparison of the two models discloses several similarities namely according to FMM and SPM structures and their responsibilities to manage, control of farm assets on behalf of the communities; they use the same communication channel systems to communicate with the community and other stakeholders and the appointment of the project facilitator/coordinator to facilitate and coordinate the activities. The most important differences between the two models are: <ul> <li> A scientific company was formed by the SPM to manage the farm as a business while the CPA kept that responsibility to itself in the FMM.</li> <li> The Traditional Authority at the FMM attend all CPA meetings while at the SPM do not attend all the CT meetings.</li> </ul> The study reveals that the following actions are essential for the successful post-settlement to restitution farms: <ul> <li> The execution of baseline study (survey) to determine the socio-economic situation in a community (beneficiaries).</li> <li> The appointment of an independent Project facilitator/coordinator to ensure effective and efficient communication.</li> <li> A well defined management structure and the appointment of a knowledgeable, skilful and experienced farm manager(s) or Strategic Partner.</li> <li> The development of a business plan for the farm with the support of professional agriculturist.</li> <li> The identification of qualified professional extension advisor to provide advice and guidance to the manager(s) or Strategic Partner.</li> <li> Appointment of a mentor to guide, advice and train the manager(s) or Strategic Partner.</li> <li> Financial support to manage the farm (Grants; Comprehensive Agricultural Support Program; financial institutions and specifically the Land Bank)</li></ul>. / Dissertation (MSc (Agric))--University of Pretoria, 2012. / Agricultural Economics, Extension and Rural Development / unrestricted
43

DFT simulace interakce organických molekul s orientovanými povrchy / DFT simulations of interaction of organic molecules with oriented surfaces

Krejčí, Ondřej January 2017 (has links)
This thesis concerns my theoretical calculations and simulations in comparison with experimental measurements acquired by means of surface science techniques on bare surfaces and molecules adsorbed on surfaces. In the beginning of the thesis I briefly describe the density functional theory (DFT) method, which is used for calculations of geometric and electronic structure of surfaces and absorbed molecules. It is followed by a quick overview of the scanning probe microscopy (SPM) and X-ray spectroscopy techniques that provided experimental context for my calculations. In the later part of my thesis I introduce publications on which I participated. In these works, direct results of my DFT calculations or simulations based on DFT outputs helped to reveal geometric and electronic structure of acetophenone adsorbed on Si(111) surface, on-surface oligomerized organic molecules and boron atoms used for substitational doping of graphene. The simulations also enable us to probe a laser initiated CO hydrogenation in real time. A big part of my work was the development of some simulation methods for SPM imaging of molecules on surfaces with flexible tip apexes. These simulation methods helped to create a comprehensive overview of SPM techniques performed with flexible tip apexes. 1
44

Image Degradation Due To Surface Scattering In The Presence Of Aberrations

Choi, Narak 01 January 2012 (has links)
This dissertation focuses on the scattering phenomena by well-polished optical mirror surfaces. Specifically, predicting image degradation by surface scatter from rough mirror surfaces for a two-mirror telescope operating at extremely short wavelengths (9nm~30nm) is performed. To evaluate image quality, surface scatter is predicted from the surface metrology data and the point spread function in the presence of both surface scatter and aberrations is calculated. For predicting the scattering intensity distribution, both numerical and analytic methods are considered. Among the numerous analytic methods, the small perturbation method (classical Rayleigh-Rice surface scatter theory), the Kirchhoff approximation method (classical BeckmanKirchhoff surface scatter theory), and the generalized Harvey-Shack surface scatter theory are adopted. As a numerical method, the integral equation method (method of moments) known as a rigorous solution is discussed. Since the numerical method is computationally too intensive to obtain the scattering prediction directly for the two mirror telescope, it is used for validating the three analytic approximate methods in special cases. In our numerical comparison work, among the three approximate methods, the generalized Harvey-Shack model shows excellent agreement to the rigorous solution and it is used to predict surface scattering from the mirror surfaces. Regarding image degradation due to surface scatter in the presence of aberrations, it is shown that the composite point spread function is obtained in explicit form in terms of convolutions of the geometrical point spread function and scaled bidirectional scattering distribution functions of the individual surfaces of the imaging system. The approximations and assumptions in this iv formulation are discussed. The result is compared to the irradiance distribution obtained using commercial non-sequential ray tracing software for the case of a two-mirror telescope operating at the extreme ultra-violet wavelengths and the two results are virtually identical. Finally, the image degradation due to the surface scatter from the mirror surfaces and the aberration of the telescope is evaluated in terms of the fractional ensquared energy (for different wavelengths and field angles) which is commonly used as an image quality requirement on many NASA astronomy programs.
45

The dynamics of suspended particles in a seasonally stratified coastal sea

Cross, Jaimie January 2013 (has links)
A comprehensive investigation into the relationship between physical forcing and sus- pended particles in the shallow shelf region of the Western English Channel has been conducted, in order to evaluate the temporal dynamics of suspended particle populations. Measurements were taken across tidal cycles and seasons at station L4, part of the Western Channel Observatory (WCO), using the combination of a free-fall microstructure profiler and holographic imaging. Confirmation that L4 is weakly stratified is given, and that the formation of the seasonal thermocline is substantially altered by the spring-neap cy- cle. Stratification is variable and prone to periodic and partial erosion from atmospheric forcing during any point in any season. L4 undergoes moderate turbulent dissipation, principally as a result of tidal forcing. Typically, values of ε do not exceed 10−4 W kg−1 . L4 also exhibits tidal asymmetry, chiefly in response to stratification which, albeit weak, is frequently able to suppress turbulence when generated from the sea bed. The potential energy anomaly is small at L4, as expected for a weakly-stratified environment. Maxi- mum values in summer were shown to not exceed 50 J m−3 . Values of bed stress, τ0 , are rarely greater than around 0.18 N m−2 . Nonetheless, the critical erosion threshold falls below this, and is therefore smaller than that observed in similar locations around the UK. Seasonality in the amount of material resuspended from the seabed is important at L4. The presence of certain biological particles strongly influence particle size and may also determine if a given particle is lifted from the bed. Particles ≥ 200 μm are relatively rare, the site is dominated by particles smaller than this value in line with many other UK sites. Under certain conditions the theoretical maximum limit of particle size, the Kolmogorov length scale, does not hold and many examples of occasions when this threshold is exceeded are shown. This may generate important consequences in subsequent work undertaken at this site and other temperate shelf locations globally, particularly as these results indicate that maximum particle size appears to be governed less by the size of the local turbulent eddies and more by the presence of biological particles. This is another key seasonal component to particle dynamics in the Western English Channel. Phytoplankton populations are readily advected into and out of the L4 site, calling into question the current sampling strategy of the WCO to rely exclusively upon point measurements. Small increases in atmospheric forcing have the ability to rapidly disperse patches of phytoplankton, possibly to the point of cell mortality. Traditional sampling techniques for assessing zooplankton density have been shown to radically underestimate the number of animals present at L4, which will increase error estimates on current ecosystem models.
46

Quantification des anomalies neurologiques métaboliques et imagerie de sources électriques

Person, Christophe 19 June 2012 (has links) (PDF)
Un traitement possible de l'épilepsie partielle pharmaco-résistante consiste en l'exérèse de la région cérébrale responsable des crises. La difficulté est de localiser cette zone et d'en définir l'étendue. L'objectif de cette thèse est d'apporter des données permettant de préciser la localisation et le volume des régions pathologiques, en exploitant deux modalités : l'imagerie TEP (Tomographie par Emission de Positons) et l'EEGHR (EEG Haute Résolution : signaux cérébraux recueillis sur le scalp avec un nombre important d'électrodes et une fréquence d'échantillonnage élevée). En imagerie TEP, il s'agit de segmenter les zones d'hypométabolisme qui sont liées aux régions responsables des crises. Des méthodes de comparaisons statistiques à l'aide d'outils de type SPM (Statistical ParametricMapping) entre les images TEP de sujets pathologiques et de sujets sains ont été appliquées, en effectuant des tests d'hypothèse voxel à voxel entre les différentes images. Pour pouvoir être comparées à une population de référence, les différentes images ont subi des transformations non linéaires afin que chaque voxel corresponde à la même région anatomique chez tous les sujets. Deux algorithmes ont été appliqués : une méthode SPM classique et une méthode Block-Matching. Les résultats sont comparés par analyse subjective clinique et également sur des données simulées. En ce qui concerne l'EEG-HR, la localisation spatiale et temporelle de sources d'événements intercritiques (pointes et ondes lentes) a été réalisée par résolution du problème inverse. Ceci a permis de localiser les sources électriques intracérébrales d'intérêt qui sont à l'origine des signaux acquis sur le scalp. Enfin, une représentation des données multimodales (images TEP et signaux EEG-HR) dans un même référentiel a permis d'accroître les connaissances sur les relations existant entre les activités électriques et métaboliques et ainsi de mieux définir les régions épileptogènes.
47

Underhållskoncept : tillståndsbaserat underhåll på smörj- och hydrauloljesystem / Maintenance concept : condition based maintenance for lube and control oil system

Öhrn, Viktor, Sjöblom, Mikael January 2008 (has links)
Abstract This report describes our ten week long thesis work which is the last task in our education in mechanical engineering at Linköpings University. The project has been performed at Siemens Industrial Turbomachinery AB’s service department. The company which is located in Finspång produces, sells and provides service for steam and gas turbines around the world. The purpose of this project is to help Siemens develop their maintenance programs for two of the auxiliary systems which are a part of the complete steam turbine system. These are lube and control oil systems. The project is restricted to two of Siemens maintenance products, No Stop Check (NSC) and the annual Safety Inspection (SI). Some parts of the major and limited overhauls have also been investigated. During the work different maintenance concepts have been investigated and evaluated. Focus has been centered on finding possible solutions that allow maintenance work while the steam turbine system is running. The economical consequences are enormous if the turbine has to be shut down. This due to today’s expanded capacity of the plants. Many discussions and interviews have taken place during the project. Information has also been obtained from documents, literature and the Internet. A Failure Mode and Effect Criticality Analysis (FMECA) has also been input for the task, especially while maintenance measures and concepts were discussed. The present maintenance that Siemens supplies are mostly based on time and experience. We have tried to implement a more condition based maintenance. A lot of time has therefore been spent finding methods for reliable measuring of the machinery condition. The work has generated a lot of different recommendations for the future maintenance. These are more or less condition based and tailor-made for Siemens steam turbine systems. We hope that these propositions will be used in the future maintenance work and also to give some new ideas on how to develop the condition based maintenance at Siemens. / Sammanfattning Denna rapport beskriver vårt tio veckor långa examensarbete som är den avslutande delen i vår maskiningenjörsutbildning. Arbetet har utförts vid serviceavdelning på Siemens Industrial Turbomachinery AB (Siemens). Siemens som ligger i Finspång tillverkar, säljer och servar ång - och gasturbinanläggningar över hela världen. Syftet med arbetet är att hjälpa Siemens att utveckla sina serviceprogram för två av de kringsystem som ingår i en ångturbinanläggning, dessa är smörj- och hydrauloljesystem. Arbetet är avgränsat till två av Siemens serviceprodukter, No Stop Check (NSC) och Säkerhetsinspektion (SI). Även vissa delar av de större revisionerna har undersökts. I arbetet har olika underhållsfilosofier undersökts och utvärderats. Fokus har riktats mot att undersöka möjligheter att utföra underhållsåtgärder med turbinanläggningen i drift. I och med den höga kapacitet dagens ångturbinanläggningar har blir de ekonomiska förlusterna enormt stora vid ett eventuellt produktionsbortfall. Under arbetets gång har många diskussioner och intervjuer ägt rum. Information har också inhämtats genom dokument, böcker och Internet. En så kallad Failure Mode and Effect Criticality Analysis (FMECA) har också legat till grund för arbetet när metoder och åtgärder för underhållet diskuterats. Siemens nuvarande underhåll är till stor del erfarenhets- och tidsbaserat. Vi har försökt att applicera ett mer tillståndsbaserat underhåll och därför har mycket tid ägnats åt att hitta metoder att tillståndskontrollera utrustningen med. Arbetet har genererat ett flertal olika rekommendationer på underhållsaktiviteter som är tillståndsbaserade och anpassade för Siemens turbinanläggningar. Tanken är att dessa förslag ska användas i det fortsatta underhållsarbetet och dessutom väcka idéer till fortsatt utveckling av tillståndsbaserat underhåll.
48

Underhållskoncept : tillståndsbaserat underhåll på smörj- och hydrauloljesystem / Maintenance concept : condition based maintenance for lube and control oil system

Öhrn, Viktor, Sjöblom, Mikael January 2008 (has links)
<p>Abstract</p><p>This report describes our ten week long thesis work which is the last task in our education in mechanical engineering at Linköpings University. The project has been performed at Siemens Industrial Turbomachinery AB’s service department. The company which is located in Finspång produces, sells and provides service for steam and gas turbines around the world.</p><p>The purpose of this project is to help Siemens develop their maintenance programs for two of the auxiliary systems which are a part of the complete steam turbine system. These are lube and control oil systems.</p><p>The project is restricted to two of Siemens maintenance products, No Stop Check (NSC) and the annual Safety Inspection (SI). Some parts of the major and limited overhauls have also been investigated.</p><p>During the work different maintenance concepts have been investigated and evaluated. Focus has been centered on finding possible solutions that allow maintenance work while the steam turbine system is running. The economical consequences are enormous if the turbine has to be shut down. This due to today’s expanded capacity of the plants.</p><p>Many discussions and interviews have taken place during the project. Information has also been obtained from documents, literature and the Internet. A Failure Mode and Effect Criticality Analysis (FMECA) has also been input for the task, especially while maintenance measures and concepts were discussed.</p><p>The present maintenance that Siemens supplies are mostly based on time and experience. We have tried to implement a more condition based maintenance. A lot of time has therefore been spent finding methods for reliable measuring of the machinery condition.</p><p>The work has generated a lot of different recommendations for the future maintenance. These are more or less condition based and tailor-made for Siemens steam turbine systems. We hope that these propositions will be used in the future maintenance work and also to give some new ideas on how to develop the condition based maintenance at Siemens.</p> / <p>Sammanfattning</p><p>Denna rapport beskriver vårt tio veckor långa examensarbete som är den avslutande delen i vår maskiningenjörsutbildning. Arbetet har utförts vid serviceavdelning på Siemens Industrial Turbomachinery AB (Siemens). Siemens som ligger i Finspång tillverkar, säljer och servar ång - och gasturbinanläggningar över hela världen.</p><p>Syftet med arbetet är att hjälpa Siemens att utveckla sina serviceprogram för två av de kringsystem som ingår i en ångturbinanläggning, dessa är smörj- och hydrauloljesystem.</p><p>Arbetet är avgränsat till två av Siemens serviceprodukter, No Stop Check (NSC) och Säkerhetsinspektion (SI). Även vissa delar av de större revisionerna har undersökts.</p><p>I arbetet har olika underhållsfilosofier undersökts och utvärderats. Fokus har riktats mot att undersöka möjligheter att utföra underhållsåtgärder med turbinanläggningen i drift. I och med den höga kapacitet dagens ångturbinanläggningar har blir de ekonomiska förlusterna enormt stora vid ett eventuellt produktionsbortfall.</p><p>Under arbetets gång har många diskussioner och intervjuer ägt rum. Information har också inhämtats genom dokument, böcker och Internet. En så kallad Failure Mode and Effect Criticality Analysis (FMECA) har också legat till grund för arbetet när metoder och åtgärder för underhållet diskuterats.</p><p>Siemens nuvarande underhåll är till stor del erfarenhets- och tidsbaserat. Vi har försökt att applicera ett mer tillståndsbaserat underhåll och därför har mycket tid ägnats åt att hitta metoder att tillståndskontrollera utrustningen med.</p><p>Arbetet har genererat ett flertal olika rekommendationer på underhållsaktiviteter som är tillståndsbaserade och anpassade för Siemens turbinanläggningar. Tanken är att dessa förslag ska användas i det fortsatta underhållsarbetet och dessutom väcka idéer till fortsatt utveckling av tillståndsbaserat underhåll.</p>
49

Graphical user interface for evaluation of knee proprioception and how it is affected by an anterior cruciate ligament (ACL) injury- a functional brain imaging study : Ett grafiskt användargränssnitt för utvärdering av knäproprioception och hur det påverkas av en korsbandsskada - en funktionell magnetresonanstomografisk studie

Johan, Wallgren January 2018 (has links)
There is a big risk that neuroreceptors located in the knee, responsible for our proprioceptive ability, are damaged after an anterior cruciate ligament (ACL) injury occurs. This may cause miscommunication between the neuroreceptors and motoric function in the brain. Due to the brains plasticity, it has been shown that brain activity patterns, presented as blood oxygen dependent level-signal (BOLD-signal), achieved from functional magnetic resonance imaging (fMRI) differs between healthy and injured individuals when performing certain tasks involving knee movement. As there is little consensus on how a proprioceptive test should be performed, a unique test were participants uses blindfold during a knee bending exercise was created at U Motion Lab, Umeå University. A Matlab based general user interface (GUI) was created for evaluation of the proprioceptive test. This GUI is communicating with the third party toolbox SPM12 and performs necessary preprocessing fMRI-image steps for statistical analysis and statistical parametric mapping of the BOLD-signal for both a healthy control- and ACL-injured group. The fMRIimages preprocessed by the GUI were generated by a 3 T GE scanner and the motion data was collected using an eight-camera 3D-motion analysis system. Time events for three different tasks was investigated. These were passive resting, memorizing and proprioceptive events. For both the control (5 participants)- and ACL (2 participants) group the main area of brain activation during the proprioceptive tests occurred in the frontal lobe. For the control group, brain activation was found in the cerebellum anterior lobe which is a possible origin for unconscious proprioception. For the ACL group activation was found in the inferior parietal lobule which involves visuomotor integration. Activation was also found in the inferior frontal gyrus which according to previous studies, may indicate risk-taking/”out of character” decisions. The results of this study indicates that the proprioceptive test seems to be a promising tool for evaluation of proprioceptive ability. However, more subjects need to be included to validate the result of this study.
50

Lokální charakterizace elektronických součástek / Local characterization of electronic devices

Müller, Pavel January 2010 (has links)
The development of micro and nanoelectronics and nanophotonics needs novel characterization techniques to ensure higher quality of designed devices. The thesis describes a use of Scanning Near-field Optical Microscopy (SNOM) in dimensional control and in local investigation of diverse physical parameters. As example of its potential, the correlation between object topography and reflection measurement of capacitors is shown.

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