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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.
71

Visual working memory and saccadic eye movements

Notice, Keisha Joy January 2013 (has links)
Saccadic eye movements, produced by the oculomotor system, are used to bring salient information in line with the high resolution fovea. It has been suggested that visual working memory, the cognitive system that temporarily stores and manipulates visual information (Baddeley & Hitch, 1974), is utilised by the oculomotor system in order to maintain saccade programmes across temporal delays (Belopolsky & Theeuwes, 2011). Saccadic eye movements have been found to deviate away from information stored in visual working memory (Theeuwes and colleagues, 2005, 2006). Saccadic deviation away from presented visual stimuli has been associated with top-down suppression (McSorley, Haggard, & Walker, 2006). This thesis examines the extent to which saccade trajectories are influenced by information held in visual working memory. Through a series of experiments behavioural memory data and saccade trajectory data were explored and evidence for visual working memory-oculomotor interaction was found. Other findings included specific interactions with the oculomotor system for the dorsal and ventral pathways as well as evidence for both bottom-up and top-down processing. Evidence of further oculomotor interaction with manual cognitive mechanisms was also illustrated, suggesting that visual working memory does not uniquely interact with the oculomotor system to preserve saccade programmes. The clinical and theoretical implications of this thesis are explored. It is proposed that the oculomotor system may interact with a variety of sensory systems to inform accurate and efficient visual processing.
72

A Top-Down Structured Programming Technique for Mini-Computers

Wu, Chin-yi Robert 05 1900 (has links)
This paper reviews numerous theoretical results on control structures and demonstrates their practical examples. This study deals with the design of run-time support routines by using top-down structured programming technique. A number of examples are given as illustration of this method. In conclusion, structured programming has proved to be an important methodology for systematic program design and development.
73

An Interpreter for the Basic Programming Language

Chang, Min-Jye S. 05 1900 (has links)
In this thesis, the first chapter provides the general description of this interpreter. The second chapter contains a formal definition of the syntax of BASIC along with an introduction to the semantics. The third chapter contains the design of data structure. The fourth chapter contains the description of algorithms along with stages for testing the interpreter and the design of debug output. The stages and actions-are represented internally to the computer in tabular forms. For statement parsing working syntax equations are established. They serve as standards for the conversion of source statements into object pseudocodes. As the statement is parsed for legal form, pseudocodes for this statement are created. For pseudocode execution, pseudocodes are represented internally to the computer in tabular forms.
74

Measuring Immersion and Enjoyment in a 2D Top-Down Game by Replacing the Mouse Input with Eye Tracking

Fransson, Jonatan, Hiiriskoski, Teemu January 2019 (has links)
Background. Eye tracking has been evaluated and tried in different 2D settings for research purposes. Most commercial games that are using eye tracking use it as an assistive extra input method and are focused around third or first person. There are few 2D games developed with eye tracking as an input method. This thesis aims to test the use of eye tracking as a replacement input method with a chosen set of mechanics for the purpose of playing a 2D top-down game with eye tracking as the main input method. Objectives. To test eye tracking in a 2D top-down game and use it as a replacement input method for the mouse in a novel effort to evaluate immersion and enjoyment. Method. To conduct this study the Tobii 4C eye tracker is used as the replacement peripheral in a 2D game prototype developed for the study. The game prototype is developed with the Unity game engine which the participants played through twice with a different input mode each time. Once with a keyboard and mouse and a second time with a keyboard and an eye tracker. The participants played different modes in alternating order to not sway the results. For the game prototype three different mechanics were implemented, to aim, search for hidden items and remove shadows. To measure immersion and enjoyment an experiment was carried out in a controlled manner, letting participants play through the game prototype and evaluating their experience. To evaluate the experience the participants answered a questionnaire with 12 questions relating to their perceived immersion and a small interview with 5 questions about their experience and perceived enjoyment. The study had a total of 12 participants. Results. The results from the data collected through the experiment indicate that the participants enjoyed and felt more involvement in the game, 10 out of 12 participants answering that they felt more involved with the game using eye tracking compared to the mouse. Analyzing the interviews, the participants stated that eye tracking made the game more difficult and less natural to control compared to the mouse. There is a potential problem that might sway the results toward eye tracking, most participants stated that eye tracking is a new experience and none of the participants had used it to play video games before. Conclusions. The results from the questionnaire prove the hypothesis with statistics, with a p-value of 0.02 < 5% for both increased involvement and enjoyment using eye tracking. Although the result might be biased due to the participant's inexperience with eye tracking in video games. Most of the participants reacted positively towards eye tracking with the most common reason being that it was a new experience to them.
75

Kognitiv kontroll, självreglering och impulsivitet / Cognitive control, self-regulation and impulsivity

Hammarberg, Maxine January 2019 (has links)
Kognitiv kontroll är förmågan att flexibelt anpassa sitt beteende till en eller flera specifika inre motiverande handlingar. Kognitiv kontroll möjliggör denna fokusering för de krav som informationsprocessen kräver. Kognitiv kontroll samt självreglering handlar bland annat om en så kallad top-down informationsprocess i ett globalt neuralt nätverk som pågår i den mänskliga hjärnan. Vi människor utövar denna kognitiva kontroll varje dag i vårat vardagliga liv utan vidare reflektioner. Detta sker genom flera informationsprocesser samtidigt och det är därför svårt att finna en enhetlig integrerad förklaring till de underliggande neurala mekanismerna. Syftet med arbetet är att förklara vad kognitiv kontroll, självreglering och impulsivitet innebär. Kopplingen mellan dessa två kognitiva kapaciteter föreskrivs i denna uppsats gällande de neurala mekanismerna och även kopplingen mellan kognitiv kontroll och självreglering i form av prestationer av både kontrollerade experiment och det vardagliga livet. Medan impulsivitet kopplat till kognitiv kontroll och självreglering är konsekvensen av när de neurala och kognitiva processerna brister i någon mening. Studier relaterat till kognitiv kontroll, inhibering och impulsbeteende använder sig bland annat av functional magnetic resonance imaging (fMRI) för att studera och undersöka detta kognitiva fenomen. Idag beskrivs impulsivitet samt bristande kontroll möjligen som ett maladaptivt beteende med hjälp av bland annat fMRI. Ytterligare fMRI studier har även visat på att kognitiv kontroll samt bristande kognitiv kontroll möjligen kan handla om en minskad eller ökad aktivering i nucleus accumbens, insulan och anterior cingulate cortex (ACC). Forskare inom ämnet har försökt att grundligt undersöka detta neurala nätverk genom flera olika perspektiv och därav presenterar uppsatsen några olika exempel av dessa ingångar för att möjliggöra ett brett perspektiv av denna komplexa mentala kapacitet. Resultaten inom ämnet visar än idag på en komplex multifaciterad natur av de underliggande neurala korrelaten.
76

La spectrométrie de masse haute résolution : application à la FT-ICR bidimensionnelle et à la protéomique dans les domaines de l’archéologie et la paléontologie / High Resolution Mass Spectrometry : Application to Two-Dimensional FT-ICR and Proteomics in the Fields of Archeology and Paleontology

Bray, Fabrice 12 December 2017 (has links)
La spectrométrie de masse est une méthode d’analyse qui permet de travailler sur une large gamme d’échantillons. Elle est utilisée dans de nombreux domaines de recherche comme la chimie analytique, la protéomique, la lipidomique et la métabolomique…Dans un premier temps, mon travail s’est focalisé sur le développement d’une méthode indépendante d’analyse de données par spectrométrie de masse à transformée de Fourier bidimensionnelle. Pour augmenter la résolution en première dimension, une analyse FT-ICR 2D avec un échantillonnage non uniforme (NUS) a été développée. L’augmentation de la résolution dans la première dimension a permis l’obtention d’une haute résolution pour les ions précurseurs. La FT-ICR 2D a été utilisée avec succès pour l’analyse de triacylglycérols contenus dans du plasma mais aussi pour l’analyse d’échantillons archéologiques.Dans un second temps, une stratégie protéomique conjointe bottom-up et top-down a été appliquée à l’analyse d’échantillons archéologiques et paléontologiques à partir d’ossements ou de céramiques. Le développement d’une méthodologie bottom-up, a permis à partir d’ossements archéologiques d’espèces inconnues l’identification des protéines et leurs modifications chimiques. Cet ossement a pu être attribué comme appartenant à l’espèce Homo sapiens. Une analyse top-down a été utilisée pour l’analyse d’échantillons archéologiques. Pour la première fois, une protéine (la caséine de lait) a été identifiée dans un échantillon archéologique d’amphore de l’époque de l’empereur Claude (1er siècle de notre ère) grâce la détection de grands fragments de caséine. / Mass spectrometry is a method of analysis which works on a wide range of sample types. It is used in many research fields such as analytical chemistry, proteomics, lipidomics and metabolomics...Firstly, my work was dedicated to the development of an independent data analysis methodology based on two-dimensional Fourier transform mass spectrometry. For increasing the resolution on the first dimension a 2D FT-ICR analysis with non-uniform sampling was developed. The resolution increase in the first dimension leading to high resolution for the precursor ions. The 2D FT-ICR has been successfully applied for the analysis of triacylglycerol contained on plasma and also for archaeological samples. This methodology led to 2D maps allowing a rapid classification of plants or animals samples.Secondly, a joint bottom-up and top-down proteomics strategy was applied for the analysis of archaeological and paleontological samples from bones or ceramics. The development of a bottom-up methodology, allowed the identification of proteins and their chemical modifications from archeological bones. These bones have been attributed to Homo sapiens. The development of a top-down methodology was applied to the analysis of archaeological ceramic. For the first time, a protein (milk casein) was identified in an archaeological sample of an amphora from Claudius emperor era (1st century A.D) via the detection of large fragments of casein. This first application of the top down proteomics showed that new information can be provided such as the in situ molecular degradation.
77

READ 180 Evaluation: Balanced Literacy in a Low-Income, Underperforming Urban High School

Lombardi, Daniel 01 January 2015 (has links)
This study investigated the effectiveness of the READ 180 balanced literacy program in addressing the problem of low reading achievement among urban minority high school students. Research has shown low reading achievement to negatively impact academic and economic success. Holdaway's theory of natural literacy, which suggests reading instruction should be purposeful and realistic, supports READ 180 as a remedial intervention. The specific purpose of the study was to evaluate READ 180 in relation to improving classroom reading achievement, standardized language arts test scores, and graduation rates among students in a low-income, high-minority urban high school. Subjects were 2 cohorts of students consisting of 619 enrolled in READ 180 during the school year of 2007-2008 and 358 students enrolled in READ 180 during the school year of 2010-2011 at an urban high school in New Jersey. Following a goals-based program evaluation design, a paired difference t test was used to evaluate classroom reading achievement; a chi-square test was used to evaluate graduation rates; and a multiple regression analysis controlling for initial status was used to evaluate performance on the standardized language arts test. Findings indicated moderate improvement in classroom reading achievement, no improvement in graduation rates, and strong improvement in standardized test scores only for English learners. Results suggested that a balanced literacy program such as READ 180 may provide effective reading remediation for English learners in low-income urban areas, thereby promoting social change through increased academic success and upward economic mobility.
78

Modelling Groundwater-River Interactions for Assessing Water Allocation Options

Ivkovic, Karen Marie-Jeanne, kardami@optusnet.com.au January 2007 (has links)
The interconnections between groundwater and river systems remain poorly understood in many catchments throughout the world, and yet they are fundamental to effectively managing water resources. Groundwater extraction from aquifers that are connected to river systems will reduce river flows, and this has implications for riverine ecosystem health, water security, aesthetic and cultural values, as well as water allocation and water management policies more generally. The decline in river flows as a consequence of groundwater extractions has the potential to threaten river basin industries and communities reliant on water resources. ¶ In this thesis the connectivity between groundwater and river systems and the impact that groundwater extractions have on river flows were studied in one of Australia’s most developed irrigation areas, the Namoi River catchment in New South Wales. ¶ Gauged river reaches in the Namoi River catchment were characterised according to three levels of information: 1) presence of hydraulic connection between aquifer-river systems; 2) dominant direction of aquifer-river flux; and 3) the potential for groundwater extraction to impact on river flows. The methods used to characterise the river reaches included the following analyses: 1) a comparison of groundwater and river channel base elevations using a GIS/Database; 2) stream hydrographs and the application of a baseflow separation filter; 3) flow duration curves and the percentage of time a river flows; 4) vertical aquifer connectivity from nested piezometer sites; and 5) paired stream and groundwater hydrographs. ¶ The theoretical responses for gaining, losing and variably gaining-losing river reaches were conceptualised along with the processes that operate in these systems. Subsequently, a map was prepared for the Namoi River catchment river reaches indicating aquifer-river connectivity and dominant direction of flux. Large areas of the Upper Namoi River catchment were found to have connected aquifer-river systems, with groundwater extraction bores located in close proximity to the rivers. Accordingly, the potential for groundwater extraction to impact on river flows in these areas was considered significant. The Lower Namoi was assessed as having mostly disconnected aquifer-river systems. ¶ In order to investigate the impacts of groundwater extraction on river flows in connected aquifer-river systems, a simple integrated aquifer-river model entitled IHACRES_GW was developed for use at the catchment scale. The IHACRES_GW model includes a dynamic, spatially-lumped rainfall-runoff model, IHACRES, combined with a simple groundwater bucket model that maintains a continuous water balance account of groundwater storage volumes for the upstream catchment area relative to the base of the stream, assumed to be the stream gauging station. The IHACRES_GW model was developed primarily: 1) to improve upon existing water allocation models by incorporating aquifer-river interactions; 2) to quantify the impacts of groundwater extraction on river flows within unregulated, connected aquifer-river systems; 3) to inform water policy on groundwater extraction; and 4) to be able to utilise the model in future integrated assessment of water allocations options at the catchment scale. ¶ The IHACRES_GW model was applied within the Cox’s Creek subcatchment in order to test its validity. The model was used to simulate a range of extraction scenarios which enabled the impacts of groundwater extractions on river flows to be assessed. In particular, the historical impacts of groundwater extraction on the timing, magnitude and frequency of baseflow events were quantified over a 15-year (1988-2003) simulation period. The IHACRES_GW model was also used to evaluate the implications of water sharing plans for the Cox’s Creek subcatchment. ¶ A spatially-lumped modelling approach in the management of water resources has a number of limitations, including those arising from the lack of spatial considerations. However, it offers a number of advantages including facilitating a better understanding of large-scale water management issues, assessing the impacts of water allocation and groundwater extraction on river flows at the catchment scale, and informing water sharing plans. In particular, this type of modelling approach lends itself to integrated assessments of water allocation options in which hydrological, ecological and socioeconomic data sets are combined, and where data is commonly aggregated to a larger scale of interest in response to the requirements of policy makers. The research findings from this thesis provide some insights into how to better manage the impacts of groundwater extraction in connected aquifer-river systems.
79

Modeling The Economic Impact of A Farming Innovation Group On A Regional Economy - A Top-Down Versus Hybrid Input-Output Approach

Gangemi, Michael Andrew, michael.gangemi@rmit.edu.au January 2008 (has links)
This thesis involves construction of input-output models measuring the economic impact of a farming innovation organisation (The Birchip Cropping Group) on the Victorian regional economy of Buloke Shire. The input-output modeling undertaken is of two forms; the first being a simple naïve top-down model, and the second a more sophisticated hybrid model. The naïve top-down model is based on input-output coefficients drawn from the Australian national input-output tables, and is regarded as naïve because these input-output coefficients are not adjusted to take account of local economic factors. The hybrid model uses the same national input-output coefficients as a base, and then modifies these coefficients to better reflect industrial conditions in the Shire using a location quotients-adjustment technique, as well as using original survey data collected from entities operating in Buloke Shire. One of the aims of the thesis is to determine whether the simpler naïve top-down approach produces results consistent with the theoretically more accurate hybrid methodology, and thus whether the naïve top-down approach represents a reliable method of conducting regional economic impact analysis. That is, can such studies be undertaken accurately using a naïve top down approach, or is it necessary to adopt the more resource intensive methodology of a hybrid model. The results of the analysis suggest construction of a hybrid model is advisable, as generally the naïve top-down approach produces over-estimates of the economic effects of the Birchip Cropping Group. That is, it appears the economic impact multipliers estimated with the naïve top-down model are too large, suggesting the time and effort involved in constructing the hybrid model was worthwhile. Using the hybrid model, the conclusion is that the Birchip Cropping Group has a significant affect on the regional economy of Buloke Shire, with the economic impact being estimated at close to $600,000 in additional output, $61,000 in additional income, and 3.5 additional jobs per year.
80

The conscious brain : Empirical investigations of the neural correlates of perceptual awareness

Eriksson, Johan January 2007 (has links)
<p>Although consciousness has been studied since ancient time, how the brain implements consciousness is still considered a great mystery by most. This thesis investigates the neural correlates of consciousness by measuring brain activity with functional magnetic resonance imaging (fMRI) while specific contents of consciousness are defined and maintained in various experimental settings. Study 1 showed that the brain works differently when creating a new conscious percept compared to when maintaining the same percept over time. Specifically, sensory and fronto-parietal regions were activated for both conditions but with different activation patterns within these regions. This distinction between creating and maintaining a conscious percept was further supported by Study 2, which in addition showed that there are both differences and similarities in how the brain works when defining a visual compared to an auditory percept. In particular, frontal cortex was commonly activated while posterior cortical activity was modality specific. Study 3 showed that task difficulty influenced the degree of frontal and parietal cortex involvement, such that fronto-parietal activity decreased as a function of ease of identification. This is interpreted as evidence of the non-necessity of these regions for conscious perception in situations where the stimuli are distinct and apparent. Based on these results a model is proposed where sensory regions interact with controlling regions to enable conscious perception. The amount and type of required interaction depend on stimuli and task characteristics, to the extent that higher-order cortical involvement may not be required at all for easily recognizable stimuli.</p>

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