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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

Digital vs Virtual Reality

Høgsborg, Laila, Albion, Luta January 2020 (has links)
This paper investigates how VR Impacts game user satisfaction. Four games were tested. Each game has a different genre to help better understand if it will affect player’s preferences in platforms. This study uses a customized ‘The Game User Experience Satisfaction Scale’ (GUESS) which has seven key factors that are used to determine a satisfaction grade for each game on each platform. The results are then compared between each other to analyze the differences and similarities. The result of this thesis showed that the playtesters preferred playing on VR, and that both people with more gaming experience and those with less, preferred VR interactions over PC.
2

A Response Selection Model for Choice Reaction Time

Tindall, Albert Douglas 10 1900 (has links)
<p> The binary choice Fast Guess Model of Ollman and Yellott was generalized to a multiple choice model and six subjects were run in a choice reaction time task to test the model. Stimulus set sizes of two, four and six were used and response accuracy and speed motivation was manipulated through specific instructions which were changed from trial to trial. Three different motivational instructions were used. In all cases, subjects were to respond with maximum accuracy but were also told on each trial to either disregard the duration of their response, respond within 440 milliseconds or respond within 300 milliseconds.</p> <p> The generalized Fast Guess Model was rejected because response time parameters of the SCR state were found to change across response accuracy-speed motivation instructions and across stimulus set sizes. Implications of these results for other classes of models were also discussed.</p> / Thesis / Doctor of Philosophy (PhD)
3

Pour une meilleure représentation de la diversité des biomes herbacés africains dans les modèles de végétation : apports des traits physionomiques, de l’indice de surface foliaire et des phytolithes de graminées / For a better representation of African grass biomes in vegetation models : inputs from grass physiognomic traits, leaf area index and phytoliths

Pasturel, Marine 12 March 2015 (has links)
Les biomes herbacés africains intertropicaux devraient faire face, dans un proche futur, à des changements drastiques. Les modèles dynamiques de végétation (DGVM) ont des difficultés à simuler les limites actuelles de ces biomes, notamment parce qu’ils ne prennent pas en compte la diversité des couverts herbacés en C4. Il est donc nécessaire de caractériser cette diversité floristique et physionomique afin qu’elle puisse être facilement prise en compte dans les DGVMs, et que les comparaisons modèle/données (phytolithes) soient possibles.Dans cet objectif, les traits physionomiques des graminées en C4 dominantes au Sénégal et en Afrique du Sud ont été répertoriés. Quatre groupes physionomiques ont été statistiquement discriminés. Ils varient avec la distribution spatiale des biomes et les précipitations régionales. Deux groupes sont fortement corrélés à l’indice de surface foliaire (LAI) et à la biomasse herbacée. Au Sénégal ces deux groupes sont bien différenciés par l’indice phytolithique Iph qui est un proxy des couverts herbacés intertropicaux. En Afrique du Sud, les phytolithes n’ont pas permis de tracer l’ensemble de la transition savane/steppe. Ces deux groupes physionomiques remplissent les critères nécessaires à la caractérisation de types fonctionnels de plantes (PFT). L’intégration de ces PFTs dans le modèle LPJ-GUESS améliore la simulation des biomes herbacés actuels et permet de proposer des simulations pour l’horizon 2100. Ces simulations montrent que l’augmentation de la durée de la saison sèche et de la concentration en CO2 atmosphérique devraient favoriser l’expansion simultanée des steppes et des savanes fermées aux dépens des savanes ouvertes. / Intertropical african herbaceous biomes are expected to face drastic changes in a near future. However Dynamic Global Vegetation Models (DGVMs) simulate their modern boundaries with poor accuracy, especially at the regional scale. DGVMs fail to consider the diversity of their C4 grass cover. Efforts are thus needed to characterize this floristic and physiognomic diversity in a way that can be used for enhancing DGVMs simulations, and enabling model/data (phytoliths) comparisons. For that purpose, physiognomic traits of dominant C4 grass species settled in Senegal and South Africa were listed. Four grass physiognomic groups were statistically identified. The abundance of four of them significantly varied with biome distributions and regional precipitation. Two grass physiognomic groups were additionally strongly correlated with leaf area index (LAI) and grass biomass. In Senegal, those two groups were also well traced by the Iph phytolith index which is a tropical grass cover proxy. In South Africa the limited set of phytolith data did not allow to observe the full savanna/steppe transition. The two physiognomic groups finally fulfilled the criteria required for creating Plant Functional Types (PFTs). Those new PFTs, parameterized in the LPJ-GUESS DGVM, enhanced the simulation of modern herbaceous biomes distribution in Senegal and South Africa. Simulations were additionally performed for the 2100 horizon. They evidence that the increase of both length of the dry season and atmospheric CO2 concentration should favor the simultaneous spread of steppes and closed savannas at the expense of open savannas.
4

Designmönster i digitala brädspel

Valencia, Isabella, Liu, Jiangyi January 2023 (has links)
Denna studie undersöker om datorspels designmönster kan användas för digitala brädspel. Den befintliga forskningen om användarupplevelsen är bred för datorspel, men forskningen om den digitala brädspelupplevelsen och dess designmönster är liten i jämförelse. Såsom forskning saknas, så saknas det verktyg och hjälpmedel för att skapa digitala brädspel. För att ta itu med detta problem använder den här studien verktygen Game User Experience Satisfaction Scale (GUESS) för att mäta spelanvändarupplevelsen samt så används Björk och Holopainen (2006) designmönstermall för att forska om speldesignmönster för datorspel kan användas för det digitala strategibrädspelet Root av Dire Wolf Digital (2020). För att kunna finna om dessa speldesignmönster kan användas i digitala strategibrädspel, så har det genomförts spelsessioner samt intervjuer baserade och anpassade på faktorer inom GUESS. Därefter, följdes Björk och Holopainens (2006) speldesignmönstermall, för att analysera och organisera den insamlade datan för att finna motsvarande speldesignmönster i det valda digitala brädspelet. Genom att diskutera de funna speldesignmönstren, fann vi att GUESS var ej ett lämpligt verktyg för att mäta spelupplevelsen för digitaliserade brädspel. Trots att GUESS inte lämpar sig för digitala brädspel så kan sammanställningen av de listade designmönster användas som en referens för framtida speldesigners beslutfattande i skapandet av digitala brädspel för att bidra till en bättre spelanvändarupplevelse. Med syfte att hjälpa framtida speldesigners i skapandet av bättre design för digitala brädspel, förväntas det att den framtida forskningen kan fylla i luckor inom området samt utveckla nya verktyg, dedikerade till mätningen av digitala brädspelsupplevelsen. / This study explores if game design patterns can be used for digital board games. The existing research on user experience is broad for computer games, whereas the research on digital board games and their design patterns are small in comparison. Just as there is a lack of research, there is a lack of tools and aids to create digital board games. To address this issue, this study uses Game User Experience Satisfaction Scale (GUESS) as a tool to measure the user experience and Björk and Holopainen (2006) design pattern template to research if this game design patterns can be used for the digital strategy board game Root from Dire Wolf Digital (2020). To find if these design patterns can be used in digital strategy board games, play tests and adapted interviews based on factors from GUESS have been made. Then, Björk and Holopainen’s (2006) template for game design patterns has been followed to analyze and organize the collected data, to find the corresponding game design patterns in the digital board game. After discussing the found game design patterns, we found that GUESS was not a suitable tool to measure the gaming experience of digitized board games. Besides this, the compilation of the listed design patterns we found that they could be used as a reference for future decision-making for game designers in the creation of digital board games, to contribute to a better game user experience. With the aim to assist future game designers in the creation of better designs for digital board games, it is expected that the future research can fill the gaps in this field, as well as develop new tools dedicated to the measurement of the digital board game experience.
5

Simulating Vegetation Migration in Response to Climate Change in a Dynamic Vegetation-climate Model

Snell, Rebecca 20 March 2013 (has links)
A central issue in climate change research is to identify what species will be most affected by variations in temperature, precipitation or CO2 and via which underlying mechanisms. Dynamic global vegetation models (DGVMs) have been used to address questions of habitat shifts, extinctions and changes in carbon and nutrient cycling. However, DGVMs have been criticized for assuming full migration and using the most generic of plant functional types (PFTs) to describe vegetation cover. My doctoral research addresses both of these concerns. In the first study, I added two new tropical PFTs to an existing regional model (LPJ-GUESS) to improve vegetation representation in Central America. Although there was an improvement in the representation of some biomes such as the pine-oak forests, LPJ-GUESS was still unable to capture the distribution of arid ecosystems. The model representations of fire, soil, and processes unique to desert vegetation are discussed as possible explanations. The remaining three chapters deal with the assumption of full migration, where plants can arrive at any location regardless of distance or physical barriers. Using LPJ-GUESS, I imposed migration limitations by using fat-tailed seed dispersal kernels. I used three temperate tree species with different life history strategies to test the new dispersal functionality. Simulated migration rates for Acer rubrum (141 m year-1) and Pinus rigida (76 m year-1) correspond well to pollen and genetic reconstructed rates. However, migration rates for Tsuga canadensis (85 m year-1) were considerably slower than historical rates. A sensitivity analysis showed that maturation age is the most important parameter for determining rates of spread, but it is the dispersal kernel which determines if there is any long distance dispersal or not. The final study demonstrates how northerly refugia populations could have impacted landscape recolonization following the retreat of the last glacier. Using three species with known refugia (Acer rubrum, Fagus grandifolia, Picea glauca), colonization rates were faster with a northerly refugia population present. The number of refugia locations also had a positive effect on landscape recolonization rates, which was most pronounced when populations were separated. The results from this thesis illustrate the improvements made in vegetation-climate models, giving us increasing confidence in the quality of future climate change predictions.
6

Simulating Vegetation Migration in Response to Climate Change in a Dynamic Vegetation-climate Model

Snell, Rebecca 20 March 2013 (has links)
A central issue in climate change research is to identify what species will be most affected by variations in temperature, precipitation or CO2 and via which underlying mechanisms. Dynamic global vegetation models (DGVMs) have been used to address questions of habitat shifts, extinctions and changes in carbon and nutrient cycling. However, DGVMs have been criticized for assuming full migration and using the most generic of plant functional types (PFTs) to describe vegetation cover. My doctoral research addresses both of these concerns. In the first study, I added two new tropical PFTs to an existing regional model (LPJ-GUESS) to improve vegetation representation in Central America. Although there was an improvement in the representation of some biomes such as the pine-oak forests, LPJ-GUESS was still unable to capture the distribution of arid ecosystems. The model representations of fire, soil, and processes unique to desert vegetation are discussed as possible explanations. The remaining three chapters deal with the assumption of full migration, where plants can arrive at any location regardless of distance or physical barriers. Using LPJ-GUESS, I imposed migration limitations by using fat-tailed seed dispersal kernels. I used three temperate tree species with different life history strategies to test the new dispersal functionality. Simulated migration rates for Acer rubrum (141 m year-1) and Pinus rigida (76 m year-1) correspond well to pollen and genetic reconstructed rates. However, migration rates for Tsuga canadensis (85 m year-1) were considerably slower than historical rates. A sensitivity analysis showed that maturation age is the most important parameter for determining rates of spread, but it is the dispersal kernel which determines if there is any long distance dispersal or not. The final study demonstrates how northerly refugia populations could have impacted landscape recolonization following the retreat of the last glacier. Using three species with known refugia (Acer rubrum, Fagus grandifolia, Picea glauca), colonization rates were faster with a northerly refugia population present. The number of refugia locations also had a positive effect on landscape recolonization rates, which was most pronounced when populations were separated. The results from this thesis illustrate the improvements made in vegetation-climate models, giving us increasing confidence in the quality of future climate change predictions.
7

Improving the Self-Consistent Field Initial Guess Using a 3D Convolutional Neural Network

Zhang, Ziang 12 April 2021 (has links)
Most ab initio simulation packages based on Density Functional Theory (DFT) use the Superposition of Atomic Densities (SAD) as a starting point of the self-consistent fi eld (SCF) iteration. However, this trial charge density without modeling atomic iterations nonlinearly may lead to a relatively slow or even failed convergence. This thesis proposes a machine learning-based scheme to improve the initial guess. We train a 3-Dimensional Convolutional Neural Network (3D CNN) to map the SAD initial guess to the corresponding converged charge density with simple structures. We show that the 3D CNN-processed charge density reduces the number of required SCF iterations at different unit cell complexity levels.
8

Caught in a Bottleneck: Habitat Loss for Woolly Mammoths in Central North America and the Ice-Free Corridor During the Last Deglaciation

Wang, Yue, Widga, Chris, Graham, Russell W., McGuire, Jenny L., Porter, Warren, Wårlind, David, Williams, John W. 01 February 2021 (has links)
Aim: Identifying how climate change, habitat loss, and corridors interact to influence species survival or extinction is critical to understanding macro-scale biodiversity dynamics under changing environments. In North America, the ice-free corridor was the only major pathway for northward migration by megafaunal species during the last deglaciation. However, the timing and interplay among the late Quaternary megafaunal extinctions, climate change, habitat structure, and the opening and reforestation of the ice-free corridor have been unclear. Location: North America. Time period: 15–10 ka. Major taxa studied: Woolly mammoth (Mammuthus primigenius). Methods: For central North America and the ice-free corridor between 15 and 10 ka, we used a series of models and continental-scale datasets to reconstruct habitat characteristics and assess habitat suitability. The models and datasets include biophysical and statistical niche models Niche Mapper and Maxent, downscaled climate simulations from CCSM3 SynTraCE, LPJ-GUESS simulations of net primary productivity (NPP) and woody cover, and woody cover based upon fossil pollen from Neotoma. Results: The ice-free corridor may have been of limited suitability for traversal by mammoths and other grazers due to persistently low productivity by herbaceous plants and quick reforestation after opening 14 ka. Simultaneously, rapid reforestation and decreased forage productivity may have led to declining habitat suitability in central North America. This was possibly amplified by a positive feedback loop driven by reduced herbivory pressures, as mammoth population decline led to the further loss of open habitat. Main conclusions: Declining habitat availability south of the Laurentide Ice Sheet and limited habitat availability in the ice-free corridor were contributing factors in North American extinctions of woolly mammoths and other large grazers that likely operated synergistically with anthropogenic pressures. The role of habitat loss and attenuated corridor suitability for the woolly mammoth extinction reinforce the critical importance of protected habitat connectivity during changing climates, particularly for large vertebrates.
9

Physical vs Digital Tabletop Games

Larsson, Andreas, Ekblad, Jonas January 2020 (has links)
This paper shows the difference in User Experience between Physical and Digital tabletop games. The goal of the project is to get an understanding of how and why playing tabletop games differentiates depending on the platform. Seven tabletop games have been chosen from different genres with an official digital adaptation. We’ve measured four key factors, Usability, Aesthetics, Social Connectivity and Engagement. The key factors have been used to gather User Experience metrics that were used to compare the digital and physical versions of the tabletop games. The result from this thesis is that physical tabletop games have a higher rating than the digital versions in all key factors except in usability where the differences were miniscule. Games that rely on imperfect information offer a much higher social connectivity and engagement when it’s played around a table. Games relying on tile-placement offers a higher usability and engagement when played digitally due to the assistance provided by the game. Physical tabletop games are the preferred option of the two but the accessibility of the digital versions makes them remain relevant.
10

論開放題與選擇題測量政治知識的適用性 / The Applicability of the Open-Ended and Multiple-Choice Format for the Measurement of Political Knowledge

潘心儀, Pan, Sin Yi Unknown Date (has links)
政治知識之於民主社會有其重要性,在政治學界中與政治知識相關的研究產出相當豐富,研究者利用政治知識此一變數進行相關研究前,對於題目如何選定、選項如何提供、題型的差異都是研究者需要去關注的重點,而本文主要的研究目的即是聚焦於討論何種題型更適合用來測量民眾的政治知識。 目前國內測量政治知識的問卷題型較為常見的為開放題與選擇題題型,在這兩類題型的討論上,前者被認為會低估受訪者政治知識程度,後者的測量結果則被質疑提供猜題空間導致高估了受訪者的政治知識程度,然而目前國內外卻缺乏足夠的實證研究來證明這兩個題型的適用性。 本文採用具有實驗設計性質的二手資料,利用前後測的方式讓受測者填答相同題目不同題型的問卷,藉此檢視各種知識程度的受測者在面對不同題型時是否會產生回應模式上的差異。本研究發現,開放題會使得較高政治知識程度的受訪者被低估,選擇題反而能準確測量出此類受訪者的知識程度。為了進一步證實受訪者在偏難的題目上所增加的猜題比例並非是來自於盲猜,本文採用多項機率單元模型來檢視受訪者於於選擇題選擇各個答項的機率。研究發現,儘管選擇題無法避免受訪者猜題,但受訪者並非是盲猜,反而會根據其具有的知識依據來答題,故政治知識程度高的受訪者能採用猜題方式答對題目,政治知識低的受訪者無法利用猜題方式猜中答案。整體而言,選擇題比起開放題更適合用來測量民眾的政治知識。 / Political knowledge plays an important role in the democratic society, and therefore there has been much research on political knowledge in the discipline of political science. To study political knowledge, political scientists have to understand the way of questions and options presented, and also the differences between a variety of question formats. This paper aims to analyze which question format is better for measuring the political knowledge of the public. The open-ended and multiple-choice items are both common formats for measuring political knowledge in Taiwan. The open-ended question is always considered to underestimate the respondents’ level of political knowledge, while the multiple-choice format is thought of overestimating the levels of political knowledge for providing the respondents with opportunity to guess. However, a strong evidence to decide the most suitable format for the measurement of political knowledge is still lacking. This paper uses the secondary data which is collected by a pretest-posttest questionnaire to examine whether guessing behavior will emerge or not when the respondents facing the same question with different formats. This research finds that open-ended questions underestimate the respondents’ knowledge levels who has higher level of political knowledge originally, but the multiple-choice questions can estimate the levels more accurately. To further confirm that the higher guess proportions in the more difficult questions are not resulted from the blind guessing, the study examines the probabilities of options selected by Multinomial Probit Model. The research finds that though the respondents may have guess more in multiple-choice question, however, they tend to answer the questions based on their knowledge instead of blind guessing. Therefore, the respondents who have higher levels of political knowledge can guess correctly, while those who have lower levels of political knowledge cannot. In summary, the multiple-choice questions are more suitable to measure people’s political knowledge.

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