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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.
31

MIDAS: Multi-device Integrated Dynamic Activity Spaces

Karadkar, Unmil Purushottam 2011 December 1900 (has links)
Mobile phones, tablet computers, laptops, desktops, and large screen displays are increasingly available to individuals for information access, often simultaneously. Dominant content access protocols, such as HTTP/1.1, do not take advantage of this device multiplicity and support information access from single devices only. Changing devices means restarting an information session. Using devices in conjunction with each other poses several challenges, which include the presentation of content on devices with diverse form factors and propagation of the content changes across these devices. In this dissertation, I report on the design and implementation of MIDAS - architecture and a prototype system for multi-device presentations. I propose a framework, called 12C, for characterizing multi-device systems and evaluate MIDAS within this framework. MIDAS is designed as a middleware that can work with multiple client-server architectures, such as the Web and context-aware Trellis, a non-Web hypertext system. It presents information content simultaneously on devices with diverse characteristics without requiring sensor-enhanced environments. The system adapts content elements for optimal presentation on the target device while also striving to retain fidelity with the original form from a human perceptual perspective. MIDAS reconfigures its presentation in response to user actions, availability of devices, and environmental context, such as a user's location or the time of day. I conducted a pilot study that explored human perception of similarity when image attributes such as size and color depth are modified in the process of presenting images on different devices. The results indicated that users tend to prefer scaling of images to color-depth reduction but gray scaling of images is preferable to either modification. Not all images scale equally gracefully; those dominated by natural elements or manmade structures scale exceptionally well. Images that depict recognizable human faces or textual elements should be scaled only to an extent that these features retain their integrity. Attributes of the 12C framework describe aspects of multi-device systems that include infrastructure, presentation, interaction, interface, and security. Based on these criteria, MIDAS is a flexible infrastructure, which lends itself to several content distribution and interaction strategies by separating client- and server-side configuration.
32

Modelagem e previsão de volatilidade realizada: evidências para o Brasil

Wink Junior, Marcos Vinício 08 April 2011 (has links)
Submitted by Cristiane Shirayama (cristiane.shirayama@fgv.br) on 2011-05-30T17:33:11Z No. of bitstreams: 1 63090100002.pdf: 637269 bytes, checksum: 70c3797dc3ee51a70250b12457f359c0 (MD5) / Approved for entry into archive by Cristiane Shirayama(cristiane.shirayama@fgv.br) on 2011-05-30T17:34:40Z (GMT) No. of bitstreams: 1 63090100002.pdf: 637269 bytes, checksum: 70c3797dc3ee51a70250b12457f359c0 (MD5) / Approved for entry into archive by Cristiane Shirayama(cristiane.shirayama@fgv.br) on 2011-05-30T17:35:51Z (GMT) No. of bitstreams: 1 63090100002.pdf: 637269 bytes, checksum: 70c3797dc3ee51a70250b12457f359c0 (MD5) / Made available in DSpace on 2011-05-30T17:36:31Z (GMT). No. of bitstreams: 1 63090100002.pdf: 637269 bytes, checksum: 70c3797dc3ee51a70250b12457f359c0 (MD5) Previous issue date: 2011-04-08 / Usando dados intradiários dos ativos mais negociados do Bovespa, este trabalho considerou dois modelos recentemente desenvolvidos na literatura de estimação e previsão de volatilidade realizada. São eles; Heterogeneous Autorregresive Model of Realized Volatility (HAR-RV), desenvolvido por Corsi (2009)e o Mixed Data Sampling (MIDAS-RV) desenvolvido por Ghysels et. al (2004). Através de medidas de comparação de previsão dentro e fora da amostra, constatou-se resultados superiores do modelo MIDAS-RV apenas para previsões dentro da amostra. Para previsões fora da amostra, no entanto, não houve diferença estatisticamente significativa entre os modelos. Também encontram-se evidências que a utilização da volatilidade realizada induz distribuições dos retornos padronizados mais próximas da normal.
33

Beyond hand-eye coordination : An exploration of eye-tracking and speech recognition as a navigation tool for interactive systems

Sjöberg, Adam, Rominger, Marcel January 2015 (has links)
The human’s ability to see, listen and speak is naturally embedded in how we interact and communicate with each other, but not only do we interact with other humans, we also spend a lot of time interacting with computers. In our study we take a starting point in embodied interaction and draw on people’s abilities from everyday life and apply them to computation in form of eye-tracking and speech recognition. Previous research mainly explored these inputs separately and little has been discovered regarding the combination. We applied a qualitative approach consisting of free surfs, task based evaluations and ten interviews, and we aimed for an understanding of how people perceive this interaction and to discover potential use contexts. The results indicate that people are positive towards the combination of eye-tracking and speech recognition for interacting with computers but found it hard to imagine a rich set of contexts in which it could be used.
34

A Survey of Ranging Patterns and Micro-Habitat Preference of Saguinus midas in Berg en Dal, Suriname

Cherundolo, Gina Marie 15 August 2018 (has links)
No description available.
35

Modeling and Simulation of the Vector-Borne Dengue Disease and the Effects of Regional Variation of Temperature in the Disease Prevalence in Homogenous and Heterogeneous Human Populations

Bravo-Salgado, Angel D 08 1900 (has links)
The history of mitigation programs to contain vector-borne diseases is a story of successes and failures. Due to the complex interplay among multiple factors that determine disease dynamics, the general principles for timely and specific intervention for incidence reduction or eradication of life-threatening diseases has yet to be determined. This research discusses computational methods developed to assist in the understanding of complex relationships affecting vector-borne disease dynamics. A computational framework to assist public health practitioners with exploring the dynamics of vector-borne diseases, such as malaria and dengue in homogenous and heterogeneous populations, has been conceived, designed, and implemented. The framework integrates a stochastic computational model of interactions to simulate horizontal disease transmission. The intent of the computational modeling has been the integration of stochasticity during simulation of the disease progression while reducing the number of necessary interactions to simulate a disease outbreak. While there are improvements in the computational time reducing the number of interactions needed for simulating disease dynamics, the realization of interactions can remain computationally expensive. Using multi-threading technology to improve performance upon the original computational model, multi-threading experimental results have been tested and reported. In addition, to the contact model, the modeling of biological processes specific to the corresponding pathogen-carrier vector to increase the specificity of the vector-borne disease has been integrated. Last, automation for requesting, retrieving, parsing, and storing specific weather data and geospatial information from federal agencies to study the differences between homogenous and heterogeneous populations has been implemented.
36

Four essays in financial econometrics / Quatre Essais sur l’Econométrie Financière

Banulescu, Denisa-Georgiana 05 November 2014 (has links)
Cette thèse se concentre sur des mesures du risque financier et la modélisation de la volatilité. L’objectifgénéral est : (i) de proposer de nouvelles techniques pour mesurer à la fois le risque systémique et lerisque à haute fréquence, et (ii) d’appliquer et d’améliorer les outils économétriques de modélisation etde prévision de la volatilité. Ce travail comporte quatre chapitres (papiers de recherche).La première partie de la thèse traite des questions liées à la modélisation et la prévision des mesuresdu risque à haute fréquence et du risque systémique. Plus précisément, le deuxième chapitre proposeune nouvelle mesure du risque systémique utilisée pour identifier les institutions financières d’importancesystémique (SIFIs). Basée sur une approche spécifique, cette mesure originale permet de décomposer lerisque global du système financier tout en tenant compte des caractéristiques de l’entreprise. Le troisièmechapitre propose des mesures du risque de marché intra-journalier dans le contexte particulier des donnéesà haute fréquence irrégulièrement espacées dans le temps (tick-by-tick).La deuxième partie de la thèse est consacrée aux méthodes d’estimation et de prévision de la volatilitéincluant directement des données à haute fréquence ou des mesures réalisées de volatilité. Ainsi, dans lequatrième chapitre, nous cherchons à déterminer, dans le contexte des modèles de mélange des fréquencesd’échantillonnage (MIDAS), si des regresseurs à haute fréquence améliorent les prévisions de la volatilitéà basse fréquence. Une question liée est de savoir s’il existe une fréquence d’échantillonnage optimaleen termes de prévision, et non de mesure de la volatilité. Le cinquième chapitre propose une versionrobuste aux jumps du modèle Realized GARCH. L’application porte sur la crise / This thesis focuses on financial risk measures and volatility modeling. The broad goal of this dissertationis: (i) to propose new techniques to measure both systemic risk and high-frequency risk, and (ii) toapply and improve advanced econometric tools to model and forecast time-varying volatility. This workhas been concretized in four chapters (articles).The first part addresses issues related to econometric modeling and forecasting procedures on bothsystemic risk and high-frequency risk measures. More precisely, Chapter 2 proposes a new systemic riskmeasure used to identify systemically important financial institutions (SIFIs). Based on a componentapproach, this original measure allows to decompose the risk of the aggregate financial system whileaccounting for the firm characteristics. Chapter 3 studies the importance and certifies the validity ofintraday High Frequency Risk (HFR) measures for market risk in the special context of irregularly spacedhigh-frequency data.The second part of this thesis tackles the need to improve the estimation/prediction of volatility bydirectly including high-frequency data or realized measures of volatility. Therefore, in Chapter 4 weexamine whether high-frequency data improve the volatility forecasts accuracy, and if so, whether thereexists an optimal sampling frequency in terms of prediction. Chapter 5 studies the financial volatilityduring the global financial crisis. To this aim, we use the largest volatility shocks, as provided by therobust version of the Realized GARCH model, to identify and analyze the events having induced theseshocks during the crisis.
37

Sistem?tica e biogeografia da linhagem Tetramerium (Acanthaceae) na Am?rica do Sul

C?rtes, Ana Luiza Andrade 22 August 2013 (has links)
Submitted by Verena Bastos (verena@uefs.br) on 2015-09-16T23:48:41Z No. of bitstreams: 1 TESE FINAL_Cortes.pdf: 14573536 bytes, checksum: 6e4acc2810a61d9e5ab81fe6e248b786 (MD5) / Made available in DSpace on 2015-09-16T23:48:41Z (GMT). No. of bitstreams: 1 TESE FINAL_Cortes.pdf: 14573536 bytes, checksum: 6e4acc2810a61d9e5ab81fe6e248b786 (MD5) Previous issue date: 2013-08-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The genera Schaueria, Streblacanthus, Pachystachys and Thyrsacanthus represent 25% of the Tetramerium lineage (Acanthaceae: Justicieae), currently with about 40 species, distributed mainly in wetlands and drylands in South America. They are herbaceous or shrubs, with large or filiform bracts and diverse floral morphology, revealing adaptations to different pollinators. Systematic studies in the group are scarce, and the only phylogenetic study (Daniel et al. 2008) included only 10% of the species, not solving the generic limits within the lineage. The biogeography of Neotropical Tetramerium lineage is quite complex, structured in three biomes: the Amazon Forest, the Atlantic Forest and Seasonally Dry Forest. Still, there are no investigations on its diversification. Using phylogenetic and biogeographic methods based on plastid (trnL-F, trnT-L, trnS-G andrps16) and nuclear (ITS)data, we complemented and assessed the previous phylogenetic hypothesis, time-calibrated the phylogeny and reconstructed the ancestral area of Tetramerium lineage, focusing particularly on the South American genera. The analysis showed three well-defined clades and the need for a new circumscription for the genera:1- Schaueria, (excluding S. azaleiflora, S. hirsuta, S. humuliflora, S. malifolia and S. parviflora) including three new species and Justicia paranaensis; 2- Pachystachys, encompassing three species of Streblacanthus (except Streblacanthus monospermus) Schaueria azaleiflora and two new species; and 3- Thyrsacanthus, comprising also Carlowrightia sulcata, Justicia angustissima and Schaueria humuliflora, and another Mexican clade (Justicia zopilotensis, J. gonzalezii, Mirandea hyssopus and Yeatesia mabryi). The lineage originated in the Old World and dispersed to the Neotropics between the Miocene and Pliocene, reaching North America, Central America and Amazon. Between the late Miocene and early Pleistocene, the dry forests lineage expanded and, concomitantly, the rainforests lineageretracted, supporting the idea of a South American dry vegetation belt during this period. The vicariance between blocks of dry forests in southwestern South America and the Caatinga in northeastern Brazil, however, indicates a fragmentation of this vegetation at least in the Lower Pleistocene, well before the Last Glacial Maxima as proposed by the Pleistocene Arc hypothesis. Based on the phylogenetic results, we present a taxonomic revision of the genusSchaueria?including identification keys, descriptions, illustrations, comments, distribution maps and a study of pollen grains and seeds under scanning electron microscopy ? and propose a new circumscription for the genus Pachystachys. Finally, we present a color guide ofphotos for South American species ofTetramerium lineage. / Os g?neros Schaueria, Streblacanthus, Pachystachys e Thyrsacanthus representam 25%da linhagem Tetramerium (Acanthaceae: Justicieae), contando atualmente com cerca de 40 esp?cies, distribu?das principalmente em zonas ?midas e secas da Am?rica do Sul. S?o plantas herb?ceas ou arbustivas, com br?cteas largas ou filiformes e morfologia floral diversa, revelando adapta??es a diferentes polinizadores. Estudos sistem?ticos no grupo s?o parcos, e o ?nico estudo filogen?tico (Daniel et al. 2008) incluiu apenas 10% das esp?cies, n?o resolvendo os limites gen?ricos na linhagem. A biogeografia da linhagem neotropical de Tetramerium ? bastante complexa, estruturada em tr?s biomas: Floresta Amaz?nica, Floresta Atl?ntica e Floresta Sazonalmente Seca. Ainda assim, n?o existem investiga??es sobre sua diversifica??o. Utilizando m?todos filogen?ticos e biogeogr?ficos baseados em dados moleculares plastidiais (trnL-F, trnT-L, trnS-G, rps16) e nucleares (ITS), n?s complementamos e avaliamos a hip?tese filogen?tica pr?via, datamos e reconstru?mos a ?rea ancestral da linhagem Tetramerium, focando particularmente nos g?neros da Am?rica do Sul. As an?lises mostraram tr?s clados bem definidos e a necessidade de uma nova circunscri??o para os g?neros:1- Schaueria (excluindo S. azaleiflora, S. hirsuta, S. humuliflora, S. malifolia e S. parviflora) incluindo tr?s novas esp?cies e Justicia paranaensis; 2- Pachystachys englobando tr?s esp?cies de Streblacanthus (exceto Streblacanthusmonospermus), Schaueria azaleiflora e duas novas esp?cies; e 3- Thyrsacanthus compreendendo tamb?m Carlowrightia sulcata, Justicia angustissima e Schaueria humuliflora, e mais um clado mexicano (Justicia zopilotensis, J. gonzalezii, Mirandea hyssopus e Yeatesia mabryi). A linhagem originou-se no Velho Mundo e dispersou para o Neotr?pico entre o Mioceno e o Plioceno, alcan?ando Am?rica do Norte, Central e Amaz?nia. Entre o final do Mioceno e o in?cio do Pleistoceno, a linhagem de florestas secas se expandiu e, concomitantemente, as linhagens de florestas ?midas se retra?ram, sustentando a ideia de uma diagonal seca neste per?odo. A vicari?ncia entre os blocos de florestas secas no sudoeste da Am?rica do Sul e da Caatinga no nordeste do Brasil, no entanto, indica uma fragmenta??o dessa forma??o pelo menos no Pleistoceno Inferior, bem antes da ?ltima M?xima Glacial, como proposto pela hip?tese do Arco do Pleistoceno. Com base nos resultados filogen?ticos, n?s apresentamos uma revis?o taxon?mica do g?nero Schaueria ? incluindo chaves de identifica??o, descri??es, ilustra??es, coment?rios, mapas de distribui??o e estudo de microscopia de varredura de gr?os de p?len e de sementes ? e propomos uma recircunscri??o para o g?nero Pachystachys. Finalmente, ? apresentado um guia de fotos coloridas para as esp?cies sul-americanas da linhagem Tetramerium.
38

Post-replicative resolution of under-replication

Carrington, James T. January 2017 (has links)
The evolutionary pressure to prevent re-replication by inactivating licensing during S phase leaves higher-eukaryotes with large genomes, such as human cells, vulnerable to replication stresses. Origins licensed in G1 must be sufficient to complete replication as new origins cannot be licensed in response to irreversible replication fork stalling. Interdisciplinary approaches between cellular biology and biophysics predict that replication of the genome is routinely incomplete in G2, even in the absence of external stressors. The frequency of converging replication forks that never terminate due to irreversible stalling (double fork stall), which result in a segment of unreplicated DNA, was modelled using high quality origin-mapping data in HeLa and IMR-90 cells. From this, hypotheses were generated that related an increase in unreplicated segments of DNA to reduced functional origin number. Presented in this thesis is the confirmation of this relation by quantifying chromosome mis-segregation and DNA damage responses when origin number was reduced using RNAi against licensing factors. The number of ultrafine anaphase bridges and 53BP1 nuclear bodies are in remarkable concordance with the theoretical predictions for the number of double fork stalls, indicating that cells are able to tolerate under-replication through such post-replicative cellular responses. 53BP1 preferentially binds to chromatin associated with large replicons, and functions synergistically with dormant origins to protect the stability of the genome. Additional candidates, inspired by common fragile site research, have also been characterised as responders to spontaneous under-replication, and include FANCD2 and MiDAS, which function in early mitosis to facilitate completion of replication before cells enter anaphase. In conclusion, a series of mechanisms that sequentially function throughout the cell cycle protects the stability of the human genome against inevitable spontaneous under-replication brought about by its large size.
39

Optimizing MIDAS III over South Africa

Giday, Nigussie Mezgebe January 2014 (has links)
In this thesis an ionospheric tomographic algorithm called Multi-Instrument Data Anal- ysis System (MIDAS) is used to reconstruct electron density profiles using the Global Positioning System (GPS) data recorded from 53 GPS receivers over the South African region. MIDAS, developed by the Invert group at the University of Bath in the UK, is an inversion algorithm that produces a time dependent 3D image of the electron density of the ionosphere. GPS receivers record the time delay and phase advance of the trans- ionospheric GPS signals that traverse through the ionosphere from which the ionospheric parameter called Total Electron Content (TEC) can be computed. TEC, the line integral of the electron density along the satellite-receiver signal path, is ingested by ionospheric tomographic algorithms such as MIDAS to produce a time dependent 3D electron density profile. In order to validate electron density profiles from MIDAS, MIDAS derived NmF2 values were compared with ionosonde derived NmF2 values extracted from their respective 1D electron density profiles at 15 minute intervals for all four South African ionosonde stations (Grahamstown, Hermanus, Louisvale, and Madimbo). MIDAS 2D images of the electron density showed good diurnal and seasonal patterns; where a comparison of the 2D images at 12h00 UT for all the validation days exhibited maximum electron concentration during the autumn and summer and a minimum during the winter. A root mean square error (rmse) value as small as 0.88x 10¹¹[el=m³] was calculated for the Louisvale ionosonde station during the winter season and a maximum rmse value of 1.92x 10¹¹[el=m³] was ob- tained during the autumn season. The r² values were the least during the autumn and relatively large during summer and winter; similarly the rmse values were found to be a maximum during the autumn and a minimum during the winter indicating that MIDAS performs better during the winter than during the autumn and spring seasons. It is also observed that MIDAS performs better at Louisvale and Madimbo than at Grahamstown and Hermanus. In conclusion, the MIDAS reconstruction has showed good agreement with the ionosonde measurements; therefore, MIDAS can be considered a useful tool to study the ionosphere over the South African region.
40

Gaze Gestures in Interaction with Problem-Solving / Gaze Gestures in Interaction with Problem-Solving

Vrzáková, Hana January 2011 (has links)
Tato diplomová práce byla vypracována při studijním pobytu na University of Eastern, Finland. Tato práce se zabývá analýzou pohybů očí jakožto charakteristiky lidských úmyslů. Během hraní hry 8Puzzle byly extrahovány pohyby očí a rozděleny na základě stisku tlačítka, které ve hře symbolizovalo hráčův úmysl pohnout herní kostičkou. Takto rozdělené sekvence představují reflexivní chování oka, tzv. pohledové gesto, které představují zdroj příznaků. Příznaky extrahované z pohybů očí pak popisují pohledová gesta spojená jak s úmysly a tak bez úmyslů. Nově bylo do analýzy zahrnuto také pozorování změn v zorničce jakožto zdroj informací, který by mohl pomoci v rozlišení úmyslných pohledů od pohledů bez záměru. Tento úkol zahrnuje binární klasifikaci, která byla realizována pomocí navrženého predikčního modelu s využitím SVM a RBF jádra. Tato práce se také zaměřuje na studium vlivu normalizace na celkové výsledky. Vyhodnocení modelu bylo realizování pomocí křivky pod grafem. Z výsledků bylo dobře patrné, že datová sada příznaků založená na fixacích a sakádách lépe rozlišila úmyslné sekvence od neúmyslných, zatímco úspěšnost sad příznaků postavených na odezvách pupily se pohybovala na hranici náhodného klasifikátoru. Přestože dosažené výsledky vyzývají k dalšímu studiu lidských úmyslů pomocí pohybů očí, přestože klasifikace v reálném čase na základě takto navržených příznaků by prozatím nebyla 100% spolehlivá.

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