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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.
1

Event Sedimentology and Hydrodynamic Hindcasting of Storm Surge Deposits: Hurricane Sandy, New Jersey

Beal, Irina January 2014 (has links)
The impact of Hurricane Sandy (October 2012) on the Atlantic Coast of the United States resulted in massive overtopping (aggradation) of coastal barriers, along with localized overwash and breaching. A combination of high-frequency ground-penetrating radar (800 MHz GPR), low-field magnetic susceptibility (MS), and textural and mineralogical analyses was used to reconstruct the sedimentological and hydrodynamic parameters of the storm surge at two New Jersey sites immediately north of hurricane landfall: 1) Mantoloking and 2) Island Beach State Park (IBSP). Mantoloking represents a developed, scour-channelized backdune area with a 30-60 cm thick deposit consisting of 20-23 event horizons. Geophysical images reveal gently landward-dipping reflections. In contrast, IBSP site is a broad (width: 40 m) vegetated dune swale. GPR transects show landward-dipping tangential-oblique reflections as well as a conformable channel cut-and-fill structure (width: 7 m; depth: 1.5 m), producing a 0.7-1.5-m-thick deposit with 24-30 horizons. Within each sand-dominated event horizon, an upward 5-15% increase in mean grain size and 80-100% decrease in MS highlight the importance of hydrodynamic equivalency in lithological segregation within mixed-density fractions. Basal sub-layers enriched in heavy minerals (magnetite, ilmenite, garnet) yield MS of 100-350 μSI, in contrast to <40 μSI in quartz-rich upper sub-layers and pre-storm deposits. Several peaks in MS values correspond to an up to 65% increase in threshold shear stresses associated with individual unidirectional surge flows, with several most-enriched event horizons likely corresponding to waning-stage storm surge peaks recorded by offshore buoys. The sharp contact with the pre-storm surface produces distinct GPR reflections that allow accurate mapping of the thickness and extent of hurricane deposits. Together with potential correlation between lithological anomalies and high amplitude georadar signal return, the approach used in this study has applications to reconstructing event deposits in Quaternary sedimentary records. The new research findings have potential implications for reconstructing surge dynamics of recent hurricane events as well as quantitative hindcasting of hydrodynamic conditions responsible for lithologically diverse intervals in ancient tempestites. / Geology / Accompanied by two .xls files (Microsoft Excel).
2

Påverka din skärmtid : En studie om hur en display i gråskala kan påverka användandet av sociala medier på smarttelefoner / Affect your screen time : A study of how a display in greyscale can affect the use of social media on smartphones

Lundqvist, Jesper, Ljungblad, Victor January 2019 (has links)
This study aims to examine how greyscale affects the screen time on smartphones and in what way it influences the user experience on the social media applications Facebook and Instagram. The use of social media applications is constantly increasing which has resulted in negative effects like difficulties with concentration and attention among individuals. Color can be used to make objects salient and draw attention to it. Color can also be used to affect the user experience through aesthetic aspects and the feelings that are connected to the interface. How greyscale affects the screen time on social media was investigated through a quantitative experiment that measured the screen time of the participants. The experiment was followed by an interview with the purpose to examine the participants’ user experience of the interface in greyscale with focus on aesthetic, emotional and functional aspects. The results show that color has importance for the way users are using social media, how long they tend to use the applications and that the screen time is reduced significantly when social media are used on a smartphone in greyscale. Further, the results also indicate that the user experience is affected by the absence of color. Aesthetic and emotional factors were the most affected by the change to greyscale. Functional factors were also affected by the removal of the colors on the interface, but not to the same extent, as the participants already knew how to use the applications.
3

Novel scalable and real-time embedded transceiver system

Mohammed, Rand Basil January 2017 (has links)
Our society increasingly relies on the transmission and reception of vast amounts of data using serial connections featuring ever-increasing bit rates. In imaging systems, for example, the frame rate achievable is often limited by the serial link between camera and host even when modern serial buses with the highest bit rates are used. This thesis documents a scalable embedded transceiver system with a bandwidth and interface standard that can be adapted to suit a particular application. This new approach for a real-time scalable embedded transceiver system is referred to as a Novel Reference Model (NRM), which connects two or more applications through a transceiver network in order to provide real-time data to a host system. Different transceiver interfaces for which the NRM model has been tested include: LVDS, GIGE, PMA-direct, Rapid-IO and XAUI, one support a specific range for transceiver speed that suites a special type for transceiver physical medium. The scalable serial link approach has been extended with loss-less data compression with the aim of further increasing dataflow at a given bit rate. Two lossless compression methods were implemented, based on Huffman coding and a novel method called Reduced Lossless Compression Method (RLCM). Both methods are integrated into the scalable transceivers providing a comprehensive solution for optimal data transmission over a variety of different interfaces. The NRM is implemented on a field programmable gate array (FPGA) using a system architecture that consists of three layers: application, transport and physical. A Terasic DE4 board was used as the main platform for implementing and testing the embedded system, while Quartus-II software and tools were used to design and debug the embedded hardware systems.
4

En grå upplevelse : Unga vuxnas spenderade tid på digitala skärmar och hur deras beteendemönster påverkas av en display i gråskala / A grey experience : Young adults’ spent time on digital screens and how their behavior patterns are affected by a display in greyscale

Dervishaj, Arberesh, Johansson, Matilda January 2021 (has links)
Tekniken utvecklas kontinuerligt och vår miljö har gradvis blivit mer digitaliserad med åren. Numera finns det således en ständig närvaro av olika digitala enheter i våra liv, såsom smartphonen. Syftet med forskningsstudien är att undersöka hur användarens beteendemönster vid användning av smartphones påverkas av ett svartvitt tema. För att svara på forskningsmålet valde författarna till studien att undersöka hur unga vuxnas spenderade tid på sina smartphones digitala skärmar påverkas av ett svartvitt tema, samt hur unga vuxna upplever den spenderade tiden på deras smartphones digitala skärmar när dessa är inställda på ett svartvitt tema. Litteraturstudien, som baserades på tidigare forskning om visualisering och digitalt beroende, gav en grund för att analysera, förklara och diskutera de insamlade empiriska data. Studien genomfördes med en mixad metod, där kvantitativa data som samlades in från sju deltagare analyserades med hjälp av det statistiska analysprogrammet SPSS; och kvalitativa data som samlades in genom individuella intervjuer med de sju deltagarna analyserades tematiskt. Resultaten visade att användarnas spenderade skärmtid på deras smartphones minskade när de ställdes in på ett svartvitt tema. Således har gråskalan en signifikant effekt på den spenderade skärmtiden. Dessutom visade resultaten att enheten inte var lika tilltalande och intressant för användarna. Gråskalan påverkade dessutom användarnas förmåga att koncentrera sig när de använde smartphone-enheten samt att användarnas koncentration blev svårare att underhålla, och navigeringen på skärmarna blev mer komplicerad. / The technology is under continuous development and our environment has gradually become more digitalized over the years. Nowadays, thus, there is a constant presence of various digital devices in our lives, such as the smartphone. The purpose of the research study is to investigate how user’s behavior patterns of the use of smartphones is affected by a black and white theme. To answer the research aim, the authors of the study chose to investigate how young adults' spent time on their smartphones’ digital screens is affected by a black and white theme, and how young adults experience the time spent on their smartphones’ digital screens when these are set on a black and white theme. The literature review, which was based on previous research on visualization and digital addiction, provided a basis for analyzing, explaining and discussing the collected empirical data. The study was conducted using a mixed methods approach, where quantitative data collected from seven participants were analyzed using the statistical analysis program SPSS; and qualitative data collected through individual interviews with the seven participants were analyzed thematically. The findings showed that the users’ spent screen time on their smartphones was reduced when it was turned into black and white theme. Thus, the gray scale has a significant effect on the spent screen time.  In addition, the findings showed that the device was not appealing and interesting for the users. Furthermore, the gray scale affected the ability of the users to concentrate, when using the smartphone device. Users’ concentration became more difficult to maintain, and the navigation on the screens became more complicated.
5

Dermatopharmacokinetics : an approach to evaluate topical drug bioavailability

Russell, Lisa Maria January 2008 (has links)
Skin, more specifically the outermost skin layer, the stratum corneum (SC), forms an extremely effective barrier, preventing both the loss of heat and water, and the ingress of micro-organisms and chemicals. Assessing the rate and extent of drug permeation into or through the skin is important both to evaluate the usefulness of a drug for topical or transdermal delivery, and to compare different formulations to assess their bioequivalence. Prediction of drug permeation is logistically, ethically and economically preferable to in vivo measurements. The recent progress that has been made with empirical and mechanistic mathematical models, along with in vitro diffusion cell techniques has been reviewed. However, currently, in vivo measurements, in man, are still required. For new chemical entities, the need for clinical trials is clear. In the case of generic products, however, there is considerable effort currently being expended to replace expensive, subjective clinical trials with objective, validated measurements of drug permeation, in vivo, in particular to assess bioequivalence. The tape stripping technique has emerged as a promising technique to objectively measure drug permeation through skin, and is the focus of this thesis. After formulation application and removal, layers of SC are sequentially removed by adhesive tapes. As the SC performs the main barrier function of the skin, measuring the rate and extent of drug permeation through this layer is assumed to be related to overall topical bioavailability. The work in this thesis concentrates on performing tape stripping studies such that all tapes are analysed individually, and drug concentration as a function of SC depth is measured. The concentration depth profiles across the SC may be fitted to an appropriate solution of Fick's second law of diffusion to obtain estimates of the vehicle-SC partition coefficient and the drug's diffusivity in the membrane. These dermato-pharmacokinetic parameters may be compared for different formulations.
6

Free space optical interconnects for speckled computing

Reardon, Christopher P. January 2009 (has links)
The aim of this project was to produce an integrate-able free space optical transceiver for Specks. Specks are tiny computing units that together can form a powerful network called a SpeckNet. The SpeckNet platform is developed by the SpeckNet consortium, which consists of five Scottish Universities and combines computer science, electrical engineering and digital signal processing groups. The principal goal of creating an optical transceiver was achieved by integrating in-house fabricated VCSELs (with lasing thresholds below 400 uA) and custom designed detectors on the SpeckNet platform. The transceiver has a very low power consumption (approximately 100 uW), which removes the need for synchronous communication through the SpeckNet thus making the network more efficient. I describe both static and dynamic beam control techniques. For static control, I used micro-lenses. I fabricated the lenses by greyscale electron beam lithography and integrated them directly on VCSEL arrays. I achieved a steering angle of 10 degrees with this design. I also looked at integrated gratings etched straight into a VCSEL and observed beam steering with an efficiency of 60% For dynamic control, I implemented a liquid crystal (LC) design. I built a LC cell with 30 individually controlled pixels, but I only achieved a steering angle of 1 degree. Furthermore, I investigated two different techniques for achieving beam steering by interference, using coupled VCSELs (a phased array approach). Firstly, using photonic crystals etched into the surface of the VCSEL, I built coupled laser cavities. Secondly, I designed and built bow-tie type VCSELs that were optically coupled but electrically isolated. These designs work by differential current injection causing an interference effect in the VCSELs far field. This technique is the first stepping stone towards realising a phased optical array. Finally, I considered signal detection. Using the same VCSEL material, I built a resonant-cavity detector. This detector had a better background rejection ratio than commercially available silicon devices.
7

Mätning av LCD-bildskärmars responstid och latens : Measurement of LCD displays response time and input lag

Mikkelsen, Markus, Svanfors, Gustav January 2013 (has links)
Examensarbetet har utförts i samarbete med företaget LVI (Low Vision International) som tillverkar elektroniska hjälpmedel för synskadade. LVI utvärderar vid jämna mellanrum nya LCD-bildskärmar för deras produkter. LVI behöver metoder samt utrustning för att mäta bildskärmars responstid och latens. Både responstiden och latensen ger fördröjningar vilket t.ex. leder till att bilden blir oskarp, rörliga föremål får en svans efter sig eller att lju- det kommer före bilden. I detta arbete utförs en grundlig förstudie som behandlar bild- skärmars responstid och latens samt ger ett underlag för att konstruera eller köpa mätut- rustning för responstidsmätningar. I förstudien framkommer den standardiserade mätmeto- den ”grey-to-grey” som LVI kan använda för att mäta responstiden. En mätkrets konstrue- ras för att mäta responstiden samt beställs en dedikerad enhet för latensmätning. För att ut- värdera mätmetoderna utförs ett antal tester med mätkretsen för responstid och den dedike- rade enheten för mätning av latens. Mätningarna visar senare att mätmetoden ”grey-to- grey” är den som LVI ska använda men metoden behöver vidareutvecklas. Den dedikerade enheten för latensmätningar visar sig mäta en del av responstiden och bör därför endast an- vändas som komplement till responstidsmätningen vid jämförelser mellan olika bildskär- mar. Arbetet levererar en förstudie i LCD-bildskärmars responstid och latens, en vidareut- vecklad version av ”grey-to-grey”-metoden, mätutrustning för responstidsmätning samt den dedikerade mätenheten för latens till företaget LVI. / The thesis was performed in collaboration with the company LVI (Low Vision Interna- tional) that manufactures electronic devices for the visually impaired. LVI evaluates new LCD displays for their products at regular intervals. LVI need methods and equipment for measuring response time and input lag. Both response time and input lag cause delays, which results in such things as image blur, ghosting after moving objects or a delay between sound and image. The preliminary study reveals the standardized method “grey- to-grey” that LVI can use to measure response time. A measurement circuit was constructed to measure response time and a dedicated unit for input lag measurement was ordered. To evaluate the measurement methods a number of tests were conducted with the response time circuit and the dedicated input lag unit. The measurements showed that the method LVI shall use is the "grey-to-grey” method but it needs further development. It turned out that the dedicated unit for input lag measured a portion of the response time and should therefore only be used as a complement to the response time measurement when comparing displays. The thesis delivers a preliminary study in LCD displays response times and input lag, a further developed version of the “grey-to-grey” method, measurement equipment for response time and a dedicated unit for input lag measurements to the company LVI.

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