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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.
471

Att öka användbarheten på en webbplats : Utvärdering och test av ett makeup-företags webbplats i anpassning till deras målgrupp med tänkbara förbättringsförslag / How to improve the usability on a website : Evaluation and testing of a makeup-brand’s website in adapting to their target users with potential improvement suggestions

Franzén, Johanna January 2016 (has links)
Viva la Diva är ett Svenskt makeup-varumärke som nyligen har lanserat sin nya webbplats. Denna webbplats har inte blivit testad på deras slutanvändare eller målgrupp. Genom att använda en heuristisk utvärdering och 12 Think aloud-tester har flera användbarhetsproblem upptäckts där designen behöver förbättringar. Senare i rapporten presenteras några förbättringsförslag om hur användarupplevelsen kan förbättras på webbplatsen, men också hur problemen som jag fann under utvärderingen och Think aloud-testerna kan lösas. Jag tillhandahåller också för Viva la Diva ett designförslag för en av deras sidor som inte är helt färdig i designen. Detta arbete ger insikt i hur man kan använda en heuristisk utvärdering och Think aloudtester för att upptäcka användbarhetsproblem på webbplatser. / Viva la Diva is a Swedish makeup-brand that has recently launched their new website. This website has not been tested with their end-users or target users. By using a heuristic evaluation and 12 Think aloud-tests several user problems have been discovered where the design needs improvements. Later in the article I present some suggestions on how to improve the user experience on the website, as well as fix the problems that I found during the evaluation and Think aloud-tests. I also provide Viva la Diva with a design suggestion for one of their pages that is not completely finished in the design. This work provides insights on how to use a heuristic evaluation and Think aloud-tests to discover usability problems on websites.
472

TCP Protocol Optimization for HTTP Adaptive Streaming / Optimisation du protocole TCP pour le streaming adaptatif sur HTTP

Ben Ameur, Chiheb 17 December 2015 (has links)
Le streaming adaptatif sur HTTP, désigné par HAS, est une technique de streaming vidéo largement déployée sur Internet. Elle utilise TCP comme protocole de transport. Elle consiste à segmenter la vidéo stockée sur un serveur web en petits segments indépendants de même durée de lecture et transcodés à plusieurs niveaux de qualité, désignés par "chunks". Le player, du côté du client HAS, demande périodiquement un nouveau chunk. Il sélectionne le niveau de qualité en se basant sur l’estimation de la bande passante du/des chunk(s) précédent(s). Étant donné que chaque client HAS est situé au sein d’un réseau d’accès, notre étude traite un cas fréquent dans l’usage quotidien: lorsque plusieurs clients partagent le même lien présentant un goulot d’étrangement et se trouvent en compétition sur la bande passante. Dans ce cas, on signale une dégradation de la qualité d’expérience (QoE) des utilisateurs de HAS et de la qualité de service (QoS) du réseau d’accès. Ainsi, l’objectif de cette thèse est d’optimiser le protocole TCP pour résoudre ces dégradations de QoE et QoS. Notre première contribution propose une méthode de bridage du débit HAS au niveau de la passerelle. Cette méthode est désignée par "Receive Window Tuning Method" (RWTM): elle utilise le principe de contrôle de flux de TCP et l’estimation passive du RTT au niveau de la passerelle. Nous avons comparé les performances de RWTM avec une méthode récente implémentée à la passerelle qui utilise une discipline particulière de gestion de la file d’attente, qui est désignée par "Hierarchical Token Bucket shaping Method" (HTBM). Les résultats d’évaluations indiquent que RWTM offre une meilleure QoE et une meilleure QoS de réseau d’accès que HTBM. Notre deuxième contribution consiste à mener une étude comparative combinant deux méthodes de bridages, RWTM et HTBM, avec quatre variantes TCP largement déployées, NewReno, Vegas, Illinois et Cubic. Les résultats d'évaluations montrent une discordance importante entre les performances des différentes combinaisons. De plus, la combinaison qui améliore les performances dans la majorité des scénarios étudiés est celle de RWTM avec Illinois. En outre, une mise à jour efficace de la valeur du paramètre "Slow Start Threshold", sthresh, peut accélérer la vitesse de convergence du player vers la qualité optimale. Notre troisième contribution propose une nouvelle variante de TCP adaptée aux flux HAS, qu’on désigne par TcpHas; c’est un algorithme de contrôle de congestion de TCP adapté aux spécifications de HAS. TcpHas estime le niveau de la qualité optimale du flux HAS en se basant sur l’estimation de la bande passante de bout en bout. Ensuite, TcpHas applique un bridage au trafic HAS en fonction du débit d’encodage du niveau de qualité estimé. TcpHas met à jour ssthresh pour accélérer la vitesse de convergence. Une étude comparative a été réalisée avec la variante Westwood+. Les résultats d’évaluations montrent que TcpHas est plus performant que Westwood+. / HTTP adaptive streaming (HAS) is a streaming video technique widely used over the Internet. It employs Transmission Control Protocol (TCP) as transport protocol and it splits the original video inside the server into segments of same duration, called "chunks", that are transcoded into multiple quality levels. The HAS player, on the client side, requests for one chunk each chunk duration and it commonly selects the quality level based on the estimated bandwidth of the previous chunk(s). Given that the HAS clients are located inside access networks, our investigation involves several HAS clients sharing the same bottleneck link and competing for bandwidth. Here, a degradation of both Quality of Experience (QoE) of HAS users and Quality of Service (QoS) of the access network are often recorded. The objective of this thesis is to optimize the TCP protocol in order to solve both QoE and QoS degradations. Our first contribution consists of proposing a gateway-based shaping method, that we called Receive Window Tuning Method (RWTM); it employs the TCP flow control and passive round trip time estimation on the gateway side. We compared the performances of RWTM with another gateway-based shaping method that is based on queuing discipline, called Hierarchical Token Bucket shaping Method (HTBM). The results of evaluation indicate that RWTM outperforms HTBM not only in terms of QoE of HAS but also in terms of QoS of access network by reducing the queuing delay and significantly reducing packet drop rate at the bottleneck.Our second contribution consists of a comparative evaluation when combining two shaping methods, RWTM and HTBM, and four very common TCP variants, NewReno, Vegas, Illinois and Cubic. The results show that there is a significant discordance in performance between combinations. Furthermore, the best combination that improves performances in the majority of scenarios is when combining Illinois variant with RWTM. In addition, the results reveal the importance of an efficient updating of the slow start threshold value, ssthresh, to accelerate the convergence toward the best feasible quality level. Our third contribution consists of proposing a novel HAS-based TCP variant, that we called TcpHas; it is a TCP congestion control algorithm that takes into consideration the specifications of HAS flow. Besides, it estimates the optimal quality level of its corresponding HAS flow based on end-to-end bandwidth estimation. Then, it permanently performs HAS traffic shaping based on the encoding rate of the estimated level. It also updates ssthresh to accelerate convergence speed. A comparative performance evaluation of TcpHas with a recent and well-known TCP variant that employs adaptive decrease mechanism, called Westwood+, was performed. Results indicated that TcpHas largely outperforms Westwood+; it offers better quality level stability on the optimal quality level, it dramatically reduces the packet drop rate and it generates lower queuing delay.
473

Catégorisation et évaluation de divers scénarios de conclusion du volet agricole du cycle de Doha pour les filières coton en Afrique de l'ouest et du centre / Impact assessment of various scenarios of Doha Agenda on West and Central Africa cotton sectors

Kone, Siaka 08 July 2011 (has links)
À l'Organisation Mondiale du Commerce (OMC), le Cycle de Doha pour le Développement, lancé en 2001, achoppe sur le volet agricole, en particulier sur le dossier coton. La thèse vise à analyser, catégoriser et évaluer les impacts des positions dans les négociations en cours du Cycle de Doha pour le Développement, émanant des États membres de l'OMC, des organisations non gouvernementales, des universitaires et des institutions internationales. L'originalité de l'évaluation réalisée est accentuée par la prise en compte d'un scénario alternatif qui tient davantage compte du traitement spécial différencié en faveur des pays en développement. Face au scénario de statu quo de l'Accord de l'Uruguay Round, les scénarios actuellement proposés sont ceux du projet de modalités révisé de Falconer de décembre 2008 sans disposition particulière pour le coton, du projet de modalités révisé de Falconer de décembre 2008 avec des dispositions particulières pour le coton (position « C4 »), et des propositions respectives de l'Union Européenne et des États-Unis. Le scénario alternatif que nous proposons intègre l'amélioration de l'accès du coton des pays africains au marché chinois et le renforcement du soutien domestique dans les pays cotonniers d'Afrique de l'Ouest et du Centre. Mais l'originalité de ce scénario additionnel procède de l'affectation des économies réalisées par les pays développés, dans la réduction de leurs soutiens domestiques, pour constituer un fonds de solidarité internationale de soutien à la filière coton des pays en développement. Par souci de comparaison, le scénario de libéralisation totale des échanges est également pris en compte, même s'il relève du domaine purement théorique. Nous avons utilisé le modèle ATPSM (Agricultural Trade Policy Simulation Model) pour mesurer les impacts des sept scénarios en termes de production et d'échanges internationaux. Notre évaluation intègre aussi la mesure de l'équité, en nous appuyant sur l'approche de Stiglitz et Charlton. Nos résultats montrent que le scénario alternatif augmente le prix aux producteurs de coton de 10,8%, mieux que les propositions du C4 (9,0%) et des USA (6,1%). Le scénario alternatif augmente le prix mondial (8,1%) et le volume des exportations de coton (2,3%), certes à un degré moindre que la proposition du C4 mais davantage que celle des États-Unis. Au regard du critère d'équité, le scénario alternatif est aussi favorable que les autres scénarios et mieux que le statu quo de l'Uruguay Round. Le scénario alternatif présente les éléments favorables à un compromis pour conclure le Cycle de Doha, avec des effets bénéfiques pour les pays en développement et l'introduction d'un mécanisme nouveau de solidarité internationale. / Agriculture, especially cotton, causes contention in the World Trade Organization's (WTO) Doha Development Agenda (DDA) since 2001. This study analyses and provides quantitative estimates of the likely economics impacts of various scenarios. We propose an alternative scenario further based on the principle of special and differential treatment provided to developing countries. We consider seven key scenarios in this study: (1) the Uruguay Round agreements, (2) Falconer' negotiation draft, revised in December 2008 but without special measures for cotton, (3) Similar Falconer's draft but including special measures for cotton as proposed by the C4 Group, (4) the European Union position, (5) the United States position, (6) our alternative scenario of agreements and (7) the total liberalization even if ambitious in scope. Our alternative scenario lies on the improvement of the access of African cotton into the Chinese market and on the strengthening of domestic support to cotton production in West and Central Africa. This scenario is original by considering the set up of a new fund for international solidarity through the subsidy savings implemented by developed countries. We use the Agricultural trade Policy Simulation Model (ATPSM) to evaluate the economic effect and the Stiglitz and Charlton theory of equity for equity assessment. The results showed that our alternative scenario increases the world cotton price by 8.1%, the producer price by 10.8% which is higher than the Falconer' negotiation draft with special measures for cotton (9.0%) and the United States position (6.1%). With regard to the equity criteria, our alternative scenario is as attractive as the other scenarios in comparison with the Uruguay Round agreements scenario. The alternative scenario can help to conclude the WTO-Doha Development Agenda. This scenario takes into account some key elements of a compromise between major actors of WTO, and provides provisions for and international fund to help the west and central Africa cotton sectors.
474

BASEBAND PROCESSOR DEVELOPMENT FOR SS-TDMA COMMUNICATION SYSTEMS

Sabourin, Donald J., Jirberg, Russell J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 13-15, 1981 / Bahia Hotel, San Diego, California / An on-board baseband processor concept developed for commercial communications satellite systems planned for the 1990s is described. The baseband processor, which operates in a time-division multiple access mode, provides significant advantages in improved link margins and system flexibility in accommodating varying demands from a large number of users because of its ability to route and control message traffic on an individual basis. This concept is currently being implemented in a proof-of-concept model with the main objective of developing the technology required to support detailed design and fabrication for an experimental satellite to be launched in 1987. This technology development includes serial MSK modems, Clos-type baseband routing switch, a singlechip custom CMOS maximum-likelihood convolutional decoder, and custom LSI implementation of high speed, low power ECL building blocks.
475

TRENDS IN GERMAN TELEMETRY SINCE THE 50’s

Mayer, G. 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 1984 / Riviera Hotel, Las Vegas, Nevada / The paper gives a short history of the beginnings in tele-meteorology and missile telemetry in Germany and describes the developments since the 50’s in these fields, and in remote control systems up to the present day.
476

DRAQ5 and Eosin (‘D&E’) as an Analog to Hematoxylin and Eosin for Rapid Fluorescence Histology of Fresh Tissues

Elfer, Katherine N., Sholl, Andrew B., Wang, Mei, Tulman, David B., Mandava, Sree H., Lee, Benjamin R., Brown, J. Quincy 27 October 2016 (has links)
Real-time on-site histopathology review of biopsy tissues at the point-of-procedure has great potential for significant clinical value and improved patient care. For instance, on-site review can aid in rapid screening of diagnostic biopsies to reduce false-negative results, or in quantitative assessment of biospecimen quality to increase the efficacy of downstream laboratory and histopathology analysis. However, the only currently available rapid pathology method, frozen section analysis (FSA), is too time-and labor-intensive for use in screening large quantities of biopsy tissues and is too destructive for maximum tissue conservation in multiple small needle core biopsies. In this work we demonstrate the spectrally-compatible combination of the nuclear stain DRAQ5 and the anionic counterstain eosin as a dual-component fluorescent staining analog to hematoxylin and eosin intended for use on fresh, unsectioned tissues. Combined with optical sectioning fluorescence microscopy and pseudo-coloring algorithms, DRAQ5 and eosin ("D&E") enables very fast, non-destructive psuedohistological imaging of tissues at the point-of-acquisition with minimal tissue handling and processing. D&E was validated against H&E on a one-to-one basis on formalin-fixed paraffin-embedded and frozen section tissues of various human organs using standard epi-fluorescence microscopy, demonstrating high fidelity of the staining mechanism as an H&E analog. The method was then applied to fresh, whole 18G renal needle core biopsies and large needle core prostate biospecimen biopsies using fluorescence structured illumination optical sectioning microscopy. We demonstrate the ability to obtain high-resolution histology-like images of unsectioned, fresh tissues similar to subsequent H&E staining of the tissue. The application of D&E does not interfere with subsequent standard-of-care H&E staining and imaging, preserving the integrity of the tissue for thorough downstream analysis. These results indicate that this dual-stain pseudocoloring method could provide a real-time histology-like image at the time of acquisition and valuable objective tissue analysis for the clinician at the time of service.
477

Serum Amyloid P Component and Systemic Fungal Infection: Does It Protect the Host or Is It a Trojan Horse?

Klotz, Stephen A., Sobonya, Richard E., Lipke, Peter N., Garcia-Sherman, Melissa C. 05 1900 (has links)
It is a striking observation that tissue of patients invaded by the deep mycoses often lacks evidence of an inflammatory response. This lack of host response is often attributed to neutropenia secondary to chemotherapy. However, systematic studies do not support this simplistic explanation. However, invasive fungal lesions are characterized by abundant fungal functional amyloid, which in turn is bound by serum amyloid P component (SAP). We postulate that SAP is important in the local immune response in invasive fungal infections. The interaction between fungal functional amyloid, SAP, and the immune response in deep mycoses is discussed.
478

Adipose-derived human stem/stromal cells: comparative organ specific mitochondrial bioenergy profiles

Ferng, Alice S., Marsh, Katherine M., Fleming, Jamie M., Conway, Renee F., Schipper, David, Bajaj, Naing, Connell, Alana M., Pilikian, Tia, Johnson, Kitsie, Runyan, Ray, Black, Stephen M., Szivek, John A., Khalpey, Zain 01 December 2016 (has links)
Background: Adipose-derived stem/stromal cells (ASCs) isolated from the stromal vascular fraction are a source of mesenchymal stem cells that have been shown to be beneficial in many regenerative medicine applications. ASCs are an attractive source of stem cells in particular, due to their lack of immunogenicity. This study examines differences between mitochondrial bioenergetic profiles of ASCs isolated from adipose tissue of five peri-organ regions: pericardial, thymic, knee, shoulder, and abdomen. Results: Flow cytometry showed that the majority of each ASC population isolated from the adipose tissue of 12 donors, with an n = 3 for each tissue type, were positive for MSC markers CD90, CD73, and CD105, and negative for hematopoietic markers CD34, CD11B, CD19, and CD45. Bioenergetic profiles were obtained for ASCs with an n = 4 for each tissue type and graphed together for comparison. Mitochondrial stress tests provided the following measurements: basal respiration rate (measured as oxygen consumption rate [pmol O-2/min], ATP production, proton leak, maximal respiration, respiratory control ratio, coupling efficiency, and non-mitochondrial respiration. Glycolytic stress tests provided the following measurements: basal glycolysis rate (measured as extracellular acidification rate [mpH/min]), glycolytic capacity, glycolytic reserve, and non-glycolytic acidification. Conclusions: The main goal of this manuscript was to provide baseline reference values for future experiments and to compare bioenergetic potentials of ASCs isolated from adipose tissue harvested from different anatomical locations. Through an investigation of mitochondrial respiration and glycolysis, it was demonstrated that bioenergetic profiles do not significantly differ by region due to depot-dependent and donor-dependent variability. Thus, although the physiological function, microenvironment and anatomical harvest site may directly affect the characteristics of ASCs isolated from different organ regions, the ultimate utility of ASCs remains independent of the anatomical harvest site.
479

Cathelicidin Insufficiency in Patients with Fatal Leptospirosis

Lindow, Janet C., Wunder, Elsio A., Popper, Stephen J., Min, Jin-na, Mannam, Praveen, Srivastava, Anup, Yao, Yi, Hacker, Kathryn P., Raddassi, Khadir, Lee, Patty J., Montgomery, Ruth R., Shaw, Albert C., Hagan, Jose E., Araújo, Guilherme C., Nery, Nivison, Relman, David A., Kim, Charles C., Reis, Mitermayer G., Ko, Albert I. 03 November 2016 (has links)
Leptospirosis causes significant morbidity and mortality worldwide; however, the role of the host immune response in disease progression and high case fatality (> 10-50%) is poorly understood. We conducted a multi-parameter investigation of patients with acute leptospirosis to identify mechanisms associated with case fatality. Whole blood transcriptional profiling of 16 hospitalized Brazilian patients with acute leptospirosis (13 survivors, 3 deceased) revealed fatal cases had lower expression of the antimicrobial peptide, cathelicidin, and chemokines, but more abundant pro-inflammatory cytokine receptors. In contrast, survivors generated strong adaptive immune signatures, including transcripts relevant to antigen presentation and immunoglobulin production. In an independent cohort (23 survivors, 22 deceased), fatal cases had higher bacterial loads (P = 0.0004) and lower anti-Leptospira antibody titers (P = 0.02) at the time of hospitalization, independent of the duration of illness. Low serum cathelicidin and RANTES levels during acute illness were independent risk factors for higher bacterial loads (P = 0.005) and death (P = 0.04), respectively. To investigate the mechanism of cathelicidin in patients surviving acute disease, we administered LL-37, the active peptide of cathelicidin, in a hamster model of lethal leptospirosis and found it significantly decreased bacterial loads and increased survival. Our findings indicate that the host immune response plays a central role in severe leptospirosis disease progression. While drawn from a limited study size, significant conclusions include that poor clinical outcomes are associated with high systemic bacterial loads, and a decreased antibody response. Furthermore, our data identified a key role for the antimicrobial peptide, cathelicidin, in mounting an effective bactericidal response against the pathogen, which represents a valuable new therapeutic approach for leptospirosis.
480

Nanofibre optic force transducers with sub-piconewton resolution via near-field plasmon–dielectric interactions

Huang, Qian, Lee, Joon, Arce, Fernando Teran, Yoon, Ilsun, Angsantikul, Pavimol, Liu, Justin, Shi, Yuesong, Villanueva, Josh, Thamphiwatana, Soracha, Ma, Xuanyi, Zhang, Liangfang, Chen, Shaochen, Lal, Ratnesh, Sirbuly, Donald J. 15 May 2017 (has links)
Ultrasensitive nanomechanical instruments, including the atomic force microscope (AFM)(1-4) and optical and magnetic tweezers(5-8), have helped shed new light on the complex mechanical environments of biological processes. However, it is difficult to scale down the size of these instruments due to their feedback mechanisms9, which, if overcome, would enable high-density nanomechanical probing inside materials. A variety of molecular force probes including mechanophores(10), quantum dots(11), fluorescent pairs(12,13) and molecular rotors(14-16) have been designed to measure intracellular stresses; however, fluorescence-based techniques can have short operating times due to photo-instability and it is still challenging to quantify the forces with high spatial and mechanical resolution. Here, we develop a compact nanofibre optic force transducer (NOFT) that utilizes strong near-field plasmon-dielectric interactions to measure local forces with a sensitivity of <200 fN. The NOFT system is tested by monitoring bacterial motion and heart-cell beating as well as detecting infrasound power in solution.

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