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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.
461

Dynamic Personal Networks for Location-Based Applications : Within MediaSense

Nilsson, Joackim January 2010 (has links)
<p>As the development of context aware applications has evolved, there has been a corresponding increase in need for more sophisticated system. The aim for this thesis is the development of a dynamical P2P network system which is based on locations. The P2P network is self organizing and in a lightweight format. Modern technical solutions including   AGPS have facilitated the work associated with the ability to position users and modern mathematical solutions such as spherical trigonometry provides the P2P system with the necessary accuracy even for short distances. The P2P system works on different Java platforms including JSE, JME and Android. Unfortunately the 3G network distributor has not yet solved a NAT traversal problem, which means that the P2P network self organization and architecture has only been proved by means of simulations. Another problem is that certain mathematical formulas are required for the spherical trigonometry and the limitation for JME is that it is unable to handle inverse trigonometry. However, the Android and JSE versions can form a correct P2P network, under the condition that the Android device uses a WIFI connection point outside the 3G distributor network system. This thesis reports the successful testing of the locations-based P2P network.</p> / MediaSense
462

ACTIONNEURS ROTATIFS MAGNETOSTRICTIFS A ACCUMULATION DE PAS

Cartier-Millon, Christophe 04 November 2002 (has links) (PDF)
Le sujet de cette thèse porte sur l'étude et la faisabilité de nouveaux actionneurs rotatifs à base de matériau actif magnétostrictifs (couplage fort entre les propriétés magnétiques et mécaniques de certains matériaux) afin de proposer des solutions innovantes pour remplacer, soit des actionneurs électriques classiques, soit des actionneurs hydrauliques dans les applications spécifiques comme l'aéronautique. Nous présenterons, de manière générale, les principaux phénomènes physiques mis en jeux, ainsi que les effets magnétostrictifs les plus remarquables. Nous comparerons ensuite ces matériaux à d'autres principes actifs, comme les piezo-électriques, à travers un état de l'art des actionneurs. Nous y aborderons les avantages économiques et les tendances d'évolutions qui font de ces matériaux adaptatifs, voire "intelligents" des objectifs économiques très importants, en mettant l'accent sur les composés magnétostrictifs dont les caractéristiques avantageuses nous intéressent particulièrement. Par la site, nous étudierons deux principes de réalisations d'actionneurs rotatifs magnétostrictifs à accumulation de pas, l'un de type spirale, l'autre de type barreau, en présentant un modèle hystérétique visant à expliquer le fondement des processus entrant en jeux, et en évaluant leurs performances par rapport à notre cahier des charges.
463

The interaction of human carbonic anhydrase II to solid surfaces and its applications

Udd, Annika January 2009 (has links)
<p><p>The adsorption of proteins to solid surfaces has been extensively investigated during the past 20-30 years. The knowledge can be applied in biotechnological applications in for example immunoassays and biosensors. Human carbonic anhydrase II is a widely studied protein and the CO<sub>2</sub>-activity makes it an interesting candidate for biotechnological purposes. To make this possible, the factors affecting the adsorption of proteins have to be mapped. The stability of the protein is under great influence of the adsorption and the protein tends to undergo conformational changes leading to a molten globule like state upon adsorption. The stability of a protein also affects the extent of conformational changes and the nature of the adsorption. A more stable protein, adsorbs with less structural changes as a consequence of adsorption, and desorbs from the surface more rapidly than a less stable one. Also the hydrophobicity, charge and area of the surface are affecting the interaction with the protein. Still, the same adsorption pattern is noticed for the same protein at different surfaces, leading to the conclusion that the properties of the protein affect the interaction, rather than the properties of the surface. Biosensors containing carbonic anhydrase have been developed. These make measurement and detection of zinc ions possible. To be able to use carbonic anhydrase as a potential agent in biotechnology, attached to solid surfaces, the protein has to be biotechnologically engineered to get a more stable structure, or else the denaturation will destroy this possibility.</p></p>
464

An Interdisciplinary Study on Farm Based Biogas Production in Southern Brazil

Hjort, Anders, Norin, Simon January 2008 (has links)
<p>Today the use of anaerobic digestion technique emerges as an alternative to the conventional treatment method of pig slurry to the pig producers in Brazil because of the energy demanding intensive pig production and the negative environmental impact that arises during storage and use. The end products of AD technique are biogas as an energy source and digestate that can be used as a fertilizer.</p><p>The study took place at two pig producers in southern Brazil in order to evaluate the biogas production in the area, its applications and environmental impact. The visited pig producers run a confined animal production system where the slurry that is used in the anaerobic digesters is diluted.</p><p>The studied digesters are covered with an air tight flexible plastic membrane that takes the shape of a balloon where each digester has the volume of 620 m3. Sedimentation occurs inside each reactor where the temperature also fluctuates. The produced biogas is conveyed to a torch where</p><p>the biogas is combusted.</p><p>The results of this study show that the digesters are working properly but there is a need for mixing and constant temperature in order to optimize the process. Biogas is primarily suited for heat production and the digestate can be used as a fertilizer. Biogas production is considered to have a positive environmental impact if the biogas is used or combusted in a torch. There is also a need to apply a cover over the digestate during the storage time to avoid ammonia emissions.</p><p>The approximated biogas potential for Rio Grande do Sul is nearly 100 GWh/year. For an</p><p>approximated biogas potential of more consideration it is found that further studies of the housing systems in Rio Grande do Sul are needed. This is due to a greatly varying amount of degradable materials in the pig slurry from one ranch to another.</p>
465

The Design & User Experiences of a Mobile Location-awareness Application: Meet App

Westerlund, Markus January 2010 (has links)
<p>This paper intends to describe the work and result of the design project Meet App. Meet App lets users interact around their current locations in a direct manner. The user experience is evaluated to get an understanding of the usefulness and interaction with this type of design. The project is related to the context-awareness research field where findings put the project in a greater whole. The result indicates usefulness and enjoyment interacting with the application, but because of the low number of participants the findings cannot be validated.</p>
466

An artificial neural network approach to laser-based direct part marking of data matrix symbols

Jangsombatsiri, Witaya 08 March 2004 (has links)
Certain applications have recently appeared in industry where a traditional bar code printed on a label will not survive because the item to be tracked has to be exposed to harsh environments. Laser direct-part marking is a manufacturing process used to create permanent marks on a substrate that could help to alleviate this problem. In this research, a 532 nm laser was utilized to create a direct-part marked Data Matrix symbol onto carbon steel substrates with different carbon content. The quality of the laser marked Data Matrix symbol was then evaluated according to the criteria outlined in the ISO/IEC 16022 bar code technology specification for Data Matrix. Several experiments were conducted to explore the effects that different parameters have on the quality of the laser direct-part marked symbols. First, an experiment was conducted to investigate the effect of two different laser tool path patterns. In later experiments, parameters such as type of carbon steel, percent of laser tool path overlap, profile speed, average power and frequency were found to have significant effects on the quality of laser direct-part marked Data Matrix symbols. The analysis of the results indicated that contrast and print growth were the critical standard performance measures that limited laser direct-part marked Data Matrix symbols from achieving a higher final grade. No significant effects were found with respect to other standard performance measures (i.e., encode, axial uniformity, and unused error correction). Next, the experimental data collected for contrast and print growth was utilized as training, validation and testing data sets in the modeling of artificial neural networks for the laser direct-part marking process. Two performance measures (i.e., mean squared error and correlation coefficient) were employed to assess the performance of the artificial neural network models. Single-output artificial neural network models corresponding to a specific performance measure were found to have good learning and predicting capabilities. The single-output artificial neural network models were compared to equivalent multiple linear regression models for validation purposes. The prediction capability of the single-output artificial neural network models with respect to laser direct-part marking of Data Matrix symbols on carbon steel substrates was superior to that of the multiple linear regression models. / Graduation date: 2004
467

The application of ablative laser ultrasonics to an aluminum plate, titanium tube, and welded joints

Butler, Chad L. 04 June 1996 (has links)
Laser ultrasonics can be used to nondestructively evaluate structures to determine the existence and location of surface and interior flaws. The goal of this research was to determine if laser ultrasonic techniques can be applied to the inspection of aluminum plate. titanium tubes, and large welded plate structures. The research was carried out with a Q-switched pulsed ruby laser emitting light of 694 nm wavelength. Ultrasonic waves were experimentally generated and recorded in the aluminum plate and the titanium tube. A comprehensive literature study was completed to determine if the technique can be applied to welded structures. For the two experimental cases, the ultrasonic waves were received by a piezoelectric pinducer which was located on the opposite side of the plate. and on the outside of the tube. A digital oscilloscope captured the signals from the pinducer. The signals were then analyzed to determine echo spacing and frequency content. The physical characteristics of the laser pulse such as the energy and full-width-half-height and amplitudes were measured via a photodiode system and a calorimeter. The aluminum plate confirmed that the system was functioning properly, as the ultrasonic echoes that were generated matched the expected results from previous experimentation. The titanium tube data turned out to be difficult to interpret due to the complex geometry and mode conversion. The welding research showed that ultrasound can be used to identify many types of flaws in a welded joint. Currently, few researchers have applied the laser based ultrasound to flaw detection in finished welds, although several have looked at using the laser ultrasound as an input to a control system for a weld in progress. The literature research uncovered the need for further studies on the application of laser based ultrasound to flaw detection in completed welds. / Graduation date: 1997
468

Statistical design and analysis of sonic wave pressure treatment of wood

Nair, Hari U. 22 June 1994 (has links)
Literature reports have indicated that application of sonic pressure waves enhances the rate of impregnation of preservatives in wood. However, these studies have been limited and inconclusive. The technique or process is not in commercial use. In this study a laboratory scale treating cylinder connected to a mechanical sonic wave generator was used to measure the rate of impregnation of water in ponderosa pine at pressures of 0.28, 0.55 and 0.69 MPa and Douglas-fir at pressures of 0.55 and 0.69 MPa at a frequency of 30 Hz. Results were compared with those obtained at the same conditions of static hydraulic pressure. Statistical analysis showed that sonic treatments were at least as effective as, but not consistently superior to, hydraulic pressure treatments in the case of ponderosa pine. Statistical analysis of the results from Douglas-fir treatment showed that sonic treatment was superior than hydraulic treatment. / Graduation date: 1995
469

Virtual application appliances on clusters

Unal, Erkan 06 1900 (has links)
Variations between the software environments(e.g., installed applications, versions of libraries) on different high-performance computing (HPC) systems lead to a heterogeneity problem. Therefore, we design an optimized, homogeneous virtual machine (VM) called a virtual application appliance (VAA). Scientists can package scientific applications, and all supporting software components, as VAAs and run them independently from the underlying heterogeneous HPC systems. However, securely moving data in and out of the VAA and controlling the execution of applications are not trivial for a non-computer scientist. Consequently, we develop two automated stage-in/stage-out secure data movement mechanisms. We also explore a migration mechanism to further simplify the control of the VAA execution. Empirical evaluation results show that VAAs achieve near-native performance in widely used bioinformatics applications that we tested. Data movement, VM boot up, shutdown and migration overheads of VAAs are negligible with respect to total run-times.
470

Learning Applications based on Semantic Web Technologies

Palmér, Matthias January 2012 (has links)
The interplay between learning and technology is a growing field that is often referred to as Technology Enhanced Learning (TEL). Within this context, learning applications are software components that are useful for learning purposes, such as textbook replacements, information gathering tools, communication and collaboration tools, knowledge modeling tools, rich lab environments that allows experiments etc. When developing learning applications, the choice of technology depends on many factors. For instance, who and how many the intended end-users are, if there are requirements to support in-application collaboration, platform restrictions, the expertise of the developers, requirements to inter-operate with other systems or applications etc. This thesis provides guidance on a how to develop learning applications based on Semantic Web technology. The focus on Semantic Web technology is due to its basic design that allows expression of knowledge at the web scale. It also allows keeping track of who said what, providing subjective expressions in parallel with more authoritative knowledge sources. The intended readers of this thesis include practitioners such as software architects and developers as well as researchers in TEL and other related fields. The empirical part of the this thesis is the experience from the design and development of two learning applications and two supporting frameworks. The first learning application is the web application Confolio/EntryScape which allows users to collect files and online material into personal and shared portfolios. The second learning application is the desktop application Conzilla, which provides a way to create and navigate a landscape of interconnected concepts. Based upon the experience of design and development as well as on more theoretical considerations outlined in this thesis, three major obstacles have been identified: The first obstacle is: lack of non-expert and user friendly solutions for presenting and editing Semantic Web data that is not hard-coded to use a specific vocabulary. The thesis presents five categories of tools that support editing and presentation of RDF. The thesis also discusses a concrete software solution together with a list of the most important features that have crystallized during six major iterations of development. The second obstacle is: lack of solutions that can handle both private and collaborative management of resources together with related Semantic Web data. The thesis presents five requirements for a reusable read/write RDF framework and a concrete software solution that fulfills these requirements. A list of features that have appeared during four major iterations of development is also presented. The third obstacle is: lack of recommendations for how to build learning applications based on Semantic Web technology. The thesis presents seven recommendations in terms of architectures, technologies, frameworks, and type of application to focus on. In addition, as part of the preparatory work to overcome the three obstacles, the thesis also presents a categorization of applications and a derivation of the relations between standards, technologies and application types. / <p>QC 20121105</p>

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