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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.
591

Designing and implementing a small scale Internet Service Provider

Brown, Johan, Gustafsson Brokås, Alexander, Hurtig, Niklas, Johansson, Tobias January 2009 (has links)
The objective of this thesis is to design and implement a small scaleInternet Service Provider (ISP) for the NetCenter sub department atMälardalen University. The ISP is intended to give NetCenter a networkseparate from the University’s network, providing them with a moreflexible environment for lab purposes. This will give their students anopportunity to experience a larger backbone with Internet accessibility,which has not been previously available. At the same time it will place theteachers in control of the network in the NetCenter lab premises.The network is designed with a layered approach including an Internetaccess layer, a larger core segment and a distribution layer with aseparated lab network. It also incorporates both a public and a privateserver network, housing servers running e.g. Windows Active Directory,external DNS services, monitoring tools and logging applications. TheInternet access is achieved by peering with SUNET providing a full BGPfeed.This thesis report presents methods, implementations and results involvedin successfully creating the NetCenter ISP as both a lab network and anInternet provider with a few inevitable shortcomings; the most prominentbeing an incomplete Windows Domain setup.
592

A process assessment framework for rural ICT projects in developing countries: an exploration of the Siyakhula Living Lab, South Africa

Osah, Umeoniso Joshua January 2013 (has links)
Rural development can be supported by information and knowledge which are key strategic resources for socio economic development. ICTs enable the facilitation and communication of information between remotely dispersed individuals or groups and more developed regions. While it has become common place that ICTs possess capabilities to potentially support rural development, the concept of ICT for development (ICT4D) is still fraught with challenges and barriers, which impede the success and sustainability of ICT4D projects. It is therefore essential to evaluate rural ICT projects, as such an analysis may aid in revealing information related to the need, effectiveness, impact, and sustainability of these projects. This research seeks to further the implementation and exploration of the Rural ICT Comprehensive Evaluation Framework (RICT-CEF), through the application of the Process Assessment domain in a real life rural ICT project environment. The RICT-CEF framework consisting of 7 evaluation domains has the primary objective of evaluating rural ICT projects from their inception stages to post implementation. A process assessment seeks to determine whether or not a rural ICT project is operating to implement its intended functions in the intended way specified in the projects plan. Such an assessment is invaluable to a comprehensive evaluation. Evaluation questions for a process assessment are centred around critical themes of project performance. Critical themes are aspects of a programme or projects implementation which must be enacted in order to achieve desired project outcomes. This research study is aimed at identifying critical themes of process assessment relevant to rural ICT4D projects. To identify critical themes, assessment approaches on social programme process assessments, evaluation of information systems in use, and rural ICT4D project evaluation case studies are comparatively analysed. Fourteen assessment approaches from these three categories are selected based on criteria. To analyse selected assessment approaches, a template is created based on the research questions, foundational literature on process assessment and identified challenges applicable to process assessments of rural ICT4D projects. Comparing and contrasting critical themes from these assessment approaches highlight critical themes essential to assess in the iterative implementation phase of rural ICT projects. Accentuated critical themes include, service utilization, organizational function and external project factors. These themes, along with suggested guiding principles from literature for conducting process assessments enable the creation of a framework for conducting process assessments of rural ICT projects. The framework is labelled "the Rural ICT Project Process Assessment Framework (RICTP-PAF)". The application of the RICTP-PAF in a real life rural ICT project through a design science case study provides lessons learned (suitability and shortcomings) from applying the framework. This essentially demonstrates the sensitivity of the RICTP-PAF to rural contexts in which it is implemented in. For instance, the implemented prototype of the RICTP-PAF reveals that the framework places a great deal of emphasis on rural beneficiary perspectives. A practice which has been lacking in such evaluation exercises. Furthermore, the guiding principles elucidated, bring to mind best practices to deal with issues such as stakeholder conflict, unreliable data elicitation and unethical assessment practices. The RICTP-PAF represents a fundamental tool for process assessments of rural ICT projects, and may be adopted and customized to various rural ICT project contexts in developing countries.
593

Development Of Fluorescent OLED And Analysis Of Integrated Optofluidic Lab-on-a Chip Sensor

Narayan, K 04 1900 (has links) (PDF)
Optofluidics is a new branch within photonics which attempts to unify concepts from optics and microfluidics. Unification of photonics and microfluidics enable us to carry out analysis of fluids through highly sensitive optical sensing device. These optical sensing devices are contained within a microchip, wherein light is made to pass through analyte (fluids of few nanoliters). The interaction between light and fluid gives rise to highly sensitive diagnostic systems. In this work the fabrication and performance characterization of a fluorescent green OLED for optofluidic applications is presented. The effect of thickness variation of hole injection (CuPc) and hole blocking (BCP) layers on the performance of fluorescent green organic light emitting diodes (OLEDs) have been studied. Even though these two organic layers have opposite functions, yet there is a particular combination of their thicknesses when they function in conjunction and luminous efficiency and power efficiency are maximized. The optimum thickness of CuPc layer, used as hole injection layer and BCP used as hole blocking layer were found to be 18 nm and 10 nm respectively. It is with this delicate adjustment of thicknesses, charge balancing was achieved and luminous efficiency and power efficiency were optimized. Such OLEDs with higher luminance can be monolithically integrated with other optical and fluidic components on a common substrate and can function as monolithically integrated internal source of light in optofluidic sensors. In this work the analysis of a fully integrated optofluidic lab-on-a-chip sensor for refractive index and absorbance based sensing using fluorescent green organic light emitting diode (OLED) as a light source is also presented. This device consists of collinear input and output waveguides which are separated by a microfluidic channel. When light is passed through the analyte contained in the fluidic gap an optical power loss due to absorption of light takes place. Apart from absorption a mode-mismatch between collinear input and output waveguide also occurs. The degree of mode-mismatch, quantum of optical power loss due to absorption of light by the fluid forms the basis of our analysis. Detection of minutest change in refractive index and changes in concentration of species contained in the analyte is indicative of sensitivity. Various parameters which influence the sensitivity of the sensor are mode spot size, refractive index of the fluid, molar concentration of the species contained in the analyte, width of the fluidic gap, waveguide geometry. By correlating various parameters, an optimal fluidic gap distance corresponding to a particular mode spot size to achieve the best sensitivity for refractive index based sensing and absorbance based sensing have been determined.
594

Compréhension et caractérisation des mécanismes physiologiques impliqués dans l'activité réductrice de Lactococcus Lactis / Understanding and characterization of physiological mechanisms involved in Lactococcus Lactis reducing activities

Michelon, Damien 15 June 2010 (has links)
Parmi les bactéries lactiques, Lactococcus lactis est la plus utilisée en fabrication fromagère. Actuellement, les ferments lactiques sont majoritairement choisis pour leurs propriétés acidifiantes, protéolytiques et aromatiques. Un autre paramètre majeur est le potentiel redox (Eh). En effet, un Eh réducteur est souvent associé à une bonne qualité aromatique. L’activité réductrice de L. lactis pourrait donc être un nouveau paramètre à prendre en compte dans la maitrise du Eh dans la fabrication des produits laitiers fermentés. Néanmoins, les mécanismes impliqués dans l’activité réductrice de L. lactis demeurent encore inconnus. L’objectif de ce présent travail de thèse a été de les découvrir. Tout d’abord, nous avons développé des milieux de culture gélosé de discrimination redox utilisant des sels de tétrazolium pour cribler une banque de mutants aléatoires de L. lactis. Ceci a permis de démontrer la participation partielle de la chaine de transport d’électrons (Ménaquinones) dans l’activité réductrice de L. lactis. Ensuite, l’approche biochimique nous a permis de déterminer les composés biochimiques principaux contribuant à la diminution du Eh vers des valeurs très réductrices. La présence de groupements thiols exofaciaux est responsable du Eh réducteur atteint par L. lactis. Enfin, l’analyse protéomique utilisant un marquage spécifique des protéines thiols de surface a mis en évidence la présence d’une dizaine de protéines exposant des groupements thiols exofaciaux potentiellement impliquées dans l’activité réductrice de L. lactis. Les thiols sont connus pour être de très puissants antioxydants ce qui confère à L. lactis un intérêt supplémentaire à prendre en considération dans l’élaboration des produits laitiers fermentés. / Among the Lactic Acid Bacteria, Lactococcus lactis is the most used in cheese making. Nowadays, starters are used mainly for their acidifying, proteolytic and flavor properties. Another important parameter is the redox potential (Eh). Indeed, reducing Eh is often related to good flavor properties. The reducing activity of L.lactis should be therefore a new parameter to take into account in the monitoring of Eh during dairy fermented products making. Nevertheless, the mechanisms involved in the reducing activity of L.lactis are still unknown. The aim of this work was to understand them. First of all, we have developed tetrazolium salts agar plate media in order to screen a random bank of mutants of L. lactis on their redox capacities. These media allowed us to demonstrate the partial implication of the electron transport chain (Menaquinone) in the reducing activities of L. lactis. Secondly, we have determined the biochemical compounds involved in the decrease of Eh to very reducing values thanks to a biochemical approach. Exofacial thiol groups are mainly responsible for the reducing Eh reached by L.lactis. Lastly, a proteomical analysis using a specific staining of thiols surface proteins revealed the presence of about ten proteins displaying thiols exofacials groups. These proteins might be involved in the reducing activity of L.lactis. Thiols are known to be very strong antioxidants which confer to L. lactis an additional interest to consider in dairy products making.
595

Optofluidique : études expérimentales, théoriques et de modélisation / Optofluidics : experimental, theoretical studies and modeling

Ali Aboulela Gaber, Noha 11 September 2014 (has links)
Ce travail porte sur l'étude de propriétés optiques des fluides à échelle micrométrique. A cet effet, nous avons conçu, réalisé et étudié différents types de micro-résonateurs optofluidiques, sous forme de laboratoires sur puce. Notre analyse est fondée sur la modélisation analytique et numérique, ainsi que sur des mesures expérimentales menées sur des micro-cavités optiques; nous utilisons l'une d'entre elles pour des applications de réfractométrie de fluides homogènes et de fluides complexes ainsi que pour la localisation par piégeage optique de microparticules solides. Nous nous sommes d'abord concentrés sur l'étude d'une nouvelle forme de micro-cavité Fabry-Pérot basée sur des miroirs courbes entre lesquels est inséré un tube capillaire permettant la circulation d'une solution liquide. Les résultats expérimentaux ont démontré la capacité de ce dispositif à être utilisé comme réfractomètre avec un seuil de détection de 1,9 × 10-4 RIU pour des liquides homogènes. De plus, pour un liquide contenant des particules solides, la capacité de contrôler la position des microparticules, par des effets de piégeage optique ou de liaison optique, a été démontrée avec succès. Dans un second temps, un résonateur optique est formé simplement à partir d'une goutte de liquide disposée sur une surface super-hydrophobe. La forme quasi-sphérique résultante est propice à des modes de galerie. Il est démontré que, jusqu'à des tailles de gouttelettes millimétriques, la technique de couplage en espace libre est toujours en mesure d'accéder à ces modes à très faible queue évanescente d'interaction, contrairement à ce qu'indiquait jusqu'ici la littérature. De tels résonateurs optofluidiques à gouttelette devraient trouver leur application notamment comme capteur d'environnement de l'air ambiant ou encore comme incubateur de micro-organismes vivants pouvant être suivis par voie optique / This work focuses on the study of optical properties of fluids at the micrometer scale. To this end, we designed, implemented and studied different types of optofluidic micro- resonators in the Lab-on-Chip format. Our analysis is based on analytical and numerical modeling, as well as experimental measurements conducted on optical microcavities; we use one of them for refractometry applications on homogeneous fluids and on complex fluids, as well as for the localization of solid microparticles by optical trapping. We first focused on the study of a new form of Fabry-Perot micro-cavity based on curved mirrors between which a capillary tube is inserted for injecting a fluidic solution. Experimental results demonstrated the ability of this device to be used as a refractometer with a detection limit of 1.9 × 10-4 RIU for homogeneous liquids. Furthermore, for liquid containing solid particles, the ability to control the microparticles position either by optical trapping or optical binding effects has been successfully demonstrated. In a second step, an optical resonator is simply formed from a liquid droplet placed on top of a superhydrophobe surface. The resulting quasi-spherical shape supports resonant whispering gallery modes. It is shown that, up to millimeter size droplets, the proposed technique of free-space coupling of light is still able to access these modes with very low evanescent tail interaction, contrary to what was indicated in the literature so far. Such optofluidic droplet resonators are expected to find their applications for environmental air quality monitoring, as well as for incubator of living micro-organisms that can be monitored optically
596

Vliv barevných modelů na chování konvolučních neuronových sítí / Impact of color models on performance of convolutional neural networks

Šimunský, Martin January 2020 (has links)
Current knowledge about impact of colour models on performance of convolutional neural network is investigated in the first part of this thesis. The experiment based on obtained knowledge is conducted in the second part. Six colour models HSV, CIE 1931 XYZ, CIE 1976 L*a*b*, YIQ a YCbCr and deep convolutional neural network ResNet-101 are used. RGB colour model achieved the highest classification accuracy, whereas HSV color model has the lowest accuracy in this experiment.
597

Spatiotemporal analysis of criteria air pollutants and volatile organic compounds from a moving vehicle

Davidson, Jon 31 August 2021 (has links)
This thesis describes the on-road analysis of criteria air pollutants (CAPs) and volatile organic compounds (VOCs) from a moving vehicle. CAPs and VOCs have numerous direct and indirect effects on the environment and public health and are generated from a variety of point and diffuse sources. The concentration of these pollutants can vary on the scale of metres and seconds due to variable emission rates of sources, meteorology, and the topography of an area. CAPs are conventionally measured on a spatial scale of tens of kilometres and one hour or longer time resolution, which limits the understanding of their impact and leaving many communities lacking information regarding their air quality. VOCs are not measured as frequently as CAPs, owing to the difficulty, challenges, and cost associated with sampling. The Mobile Mass Spectrometry Lab (MMSL) was developed to collect high geospatial (15 – 1,500 m) and temporal (1 – 10 s) resolution measurements of CAPs (O3, NOx, PM2.5), CO2, CH4, and VOCs. CAPs and greenhouse gases were monitored using standard analyzers, while VOCs were measured using a proton-transfer reaction time-of-flight mass spectrometer (PTR-MS). PTR-MS is a real-time, direct, in situ technique that can monitor VOCs in the ambient atmosphere without sample collection. The PTR-MS monitored up to mass-to-charge 330 with a sample integration time of 1 or 10 seconds and had detection limits into the low- to mid-ppt. PTR-MS is a soft ionization technique that is selective to all compounds with a proton affinity less than water, which excludes the atmospheric matrix and includes most VOCs. The measurements provided by the PTR-MS provided a rich dataset for which to develop workflow and processing methods alongside sampling strategies for the collection of high geospatial and temporal VOC data. The first on-road deployment of the MMSL was performed across the Regional District of Nanaimo and the Alberni-Clayoquot Regional District in British Columbia, Canada, from July iv 2018 – April 2019 to monitor the geospatial and temporal variation in the concentration of CAPs and VOCs. VOCs detected in the areas include hydrocarbons like toluene, C2-benzenes, and terpenes, organic acids like acetic acid, oxygenated compounds like acetone and acetaldehyde, and reduced sulfur compounds like methanethiol and dimethyl sulfide. While observed concentrations of VOCs were mostly below detection limits, concentration excursions upwards of 2,200 ppb for C2-benzenes (reported as ethylbenzene) for instance, were observed across the various communities and industries that comprise central Vancouver Island. VOCs like monoterpenes, were observed near the wood industries up to 229 ppb. Combustion related VOCs, like toluene and C2-benzenes, were often observed on major transportation corridors and was found to vary significantly between seasons, with winter measurements often exceeding those made in the summer. Reduced sulfur compounds, common components of nuisance odours, were measured around a few industries like waste management and wood industries. The second on-road deployment of the MMSL focused on the analysis of VOCs in the community around a wastewater treatment plant (WWTP) to identify the source of odours in the area. VOCs were also monitored in the odour control process of the WWTP to identify the VOCs being emitted, how much were emitted, and where potential deficiencies were in the process in a unique study. Median emission rates at the facility for methanethiol, dimethyl sulfide, and dimethyl disulfide were determined to be 100, 19, and 21 kg yr-1, respectively. VOC monitoring in the community encompassed the WWTP and the other major industries in the area, including agricultural land, a composting facility, and a marina. The highest measurements of odorous reduced sulfur compounds were observed around the WWTP, upwards of 36 ppb for methanethiol. Unsupervised multivariate analysis was performed to identify groups of VOCs present and their potential sources. Three groups were identified, one of which was related to reduced sulfur compounds. This group was observed around the WWTP, indicating that the WWTP was the likely source of malodours in the community. / Graduate
598

Řízený zdroj napětí a proudu připojitelný přes USB / USB controlled voltage and current source

Pytela, Ondřej January 2015 (has links)
This diploma thesis is focused on complete construction of lab source which is controlled and powered by USB in personal computer. Different types of possible solutions are mentioned and finally one of them has been picked up as a best choice, which is developed in the rest of this thesis. Besides hardware construction there is also shown creation of main program for PIC18F14K50 microcontroller and main application that provides controlling of USB source via personal computer.
599

Programmierung und Steuerung eines Spektralfotometers

Meissner, Robert 02 March 2007 (has links)
Aufgabe der Studienarbeit ist die Entwicklung einer Software mit grafischer Benutzeroberfläche, welche es ermöglicht, Farbtesttabellen (color test charts) mit Hilfe des Spektralfotometers Spectrolino der Firma X-Rite Incorporated (ehemals GretagMacbeth GmbH) und dem dazugehörigen XY-Tisch SpectroScan zu messen. Das zu schreibende Programm soll standardisierte und auch nicht standardisierte Testtafeln weitgehend automatisch messtechnisch erfassen können.
600

Entwicklung integrierter mikrofluidischer Aktoren für den Einsatz in bioanalytischen Systemen

Nestler, Jörg 21 December 2010 (has links)
In der vorliegenden Arbeit wird eine integrierbare Pumpentechnologie für polymerbasierte mikrofluidische Systeme entwickelt. Ausgehend von den Anforderungen für die Durchführung molekulardiagnostischer Nachweise kommen dabei Fertigungsverfahren zum Einsatz, die sich auch für Einweg-Anwendungen eignen. Das genutzte Aktorprinzip für die integrierten Mikropumpen basiert auf der Elektrolyse von Wasser. Zur besseren technologischen Integrierbarkeit wird das Wasser in Form eines Hydrogels appliziert. Der Elektrolyt wird dabei mit einer Polymermembran mit geringer Wasserdampfdurchlässigkeit verschlossen. Die Membran wird in ihrem plastischen Verformbereich genutzt. Zur Dimensionierung der Mikropumpen und des mikrofluidischen Systems werden analytische und numerische Modelle entwickelt, die eine gute Übereinstimmung mit den Messwerten zeigen. Die Funktionsfähigkeit wird anhand zweier vollständig integriert ablaufender Immunoassays demonstriert. Dabei kommt ein polymerbasierter, optischer Biosensor zum Einsatz.

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