This thesis aims to investigate an eye tracking calibration method in virtual reality where users’ visual attention from eye-hand coordination is used when interacting with in-game items. This could potentially allow eye tracking calibration without interrupting the virtual experience, in comparison with traditional eye tracking calibration which is cumbersome, disruptive, and requires the user’s full attention. A user study was conducted with 15 participants in which they were tasked to complete three different interactions. The interactions tested were a knob, a slider and a liftable cube. Where in the virtual environment the participants were looking during the interactions was recorded and processed to enable comparison. The processed data was analysed to find factors that influenced the calibration method. Additionally, the results was analysed to find at what point during the interactions that has the most consistent eye tracking fixations on the interacted item, and therefore most potential for eye tracking calibration. The results showed that when the participant is interacting with the item and the interacted item is stationary, we received a fixation for around 60% of all trials at any time. When the interacted item was moving the results indicated a lower percentage. To increase this number, the gaze data should be filtered instead of using raw gaze data in order to avoid flickering from the eye tracker. Regarding factors that influence the calibration method, the choice of interaction has a big impact on the method’s success where interactions in which the interacted item is stationary has more potential. Additionally, interactions that take longer time and requires precision in order to complete the interaction positively influences the potential of the calibration method. The surrounding virtual environment also has an influence, as a more distracting environment can negatively impact the calibration method. / Denna avhandling ämnar att att undersöka en kalibreringsmetod för ögonspårning i virtuell verklighet där användarnas visuella uppmärksamhet från ögon och hand koordination används när man interagerar med objekt i den virtuella verkligheten. Detta kan möjliggöra kalibrering av ögonspårning utan att avbryta den virtuella upplevelsen, i jämförelse med traditionell kalibrering som är besvärlig, störande och kräver användarens fulla uppmärksamhet. En användarstudie genomfördes med 15 deltagare där de hade till uppgift att slutföra tre olika interaktioner. De testade interaktionerna var en knopp, en slider och en lyftbar kub. Deltagarnas blick spelades in under interaktionerna och analyserades för att möjliggöra jämförelse. Den bearbetade data analyserades för att hitta faktorer som påverkar kalibreringsmetoden. Dessutom analyserades resultaten för att hitta vid vilken tidpunkt under interaktionerna som hade de mest konsekventa ögonfixeringarna på objektet de interagerade med och därmed störst potential för kalibrering av ögonspårning. Resultaten visade att när deltagaren interagerar med objektet och det interaktiva objektet är stillastående, fick vi en fixering för omkring 60% av alla försök under godtycklig tidpunkt. När det interaktiva objektet rörde sig, visade resultaten en lägre procentandel. För att öka antalet, ska blickdatan filtreras i stället för att använda rå blickdata för att undvika att flicker från ögonspåraren. När det gäller faktorer som påverkar kalibreringsmetoden har valet av interaktion stor inverkan på metodens framgång, där interaktioner där det interaktiva objektet är stationärt har större potential. Dessutom påverkar interaktioner som tar längre tid och kräver precision för att slutföra interaktionen kalibreringsmetodens potential positivt. Den omgivande virtuella miljön har också inflytande, eftersom en mer distraherande miljö kan negativt påverka kalibreringsmetoden.

Feedback plays a vital role in learning. With online learning on the rise, feedback can be given directly to each student in a way that can not be achieved in a traditional classroom with one teacher. But while the importance of feedback is well-known, little is known about how students interact with feedback. This study was conducted to find out how students interact with feedback from a question-based learning platform in terms of their eye movement patterns. Using an eye tracker and a multiple choice quiz, data of gaze duration in each quiz segment and gaze transactions in between segments was extracted and analyzed. The results show that students fall into three groups: 1) those who spend most time on feedback and less on the question, 2) those who spend most time on questions and less on the feedback 3) those who use a mixed approach. Students in group 1) and 3) had few gaze transactions between the questions and feedback, indicating that the feedback was used as intended. Having discovered the presence of distinct patterns of feedback interaction, the next steps will be to investigate how these impact the use and utility of the feedback by students. / Feedback spelar en avgörande roll för inlärning. Med e-learning kan feedback ges individuellt till varje elev på ett sätt som inte är möjligt i ett traditionellt klassrum med endast en lärare. Men medan vikten av feedback är välkänd, är det mindre känt hur studenter interagerar med feedback. Denna studie utfördes med syftet att ta reda på hur studenter interagerar med feedback i en frågebaserad lärplattform, när det gäller deras ögonrörelsemönster. Med hjälp av en eye tracker och ett quiz med flervalsfrågor, kunde data om deltagarnas ögonrörelser – hur länge de tittade i olika segment och vilka övergångar deras ögon gjorde mellan segment – samlas in och sedan analyseras. Resultaten visade att deltagarna hamnar i tre kategorier: 1) de som spenderar mycket tid på att läsa feedback och mindre på att läsa frågan 2) de som spenderar mycket tid på att läsa frågan och mindre på att läsa feedback och 3) de som hade ett blandat angreppssätt. Deltagare i grupperna 1) och 3) hade få blickövergångar mellan frågor och feedback, vilket indikerar att feedbacken användes som avsett av dessa deltagare. Upptäckten av distinkta mönster av interaktion med feedback öppnar upp för framtida studier att undersöka hur dessa påverkar användning och användbarheten av feedback hos studenter.

Im Rahmen dieser Arbeit wird untersucht, wie Daten der Eye-Tracking Brille Pupil Invisible genutzt werden können, um mit Methoden der Mustererkennung Mentoring-Anlässe zu erkennen. Die Arbeit ist Teil der Erforschung eines virtuellen Mentoring-Systems, welches Studierende bei der Bearbeitung von Online-Learnaufgaben auf der Lernplattform OPAL unterstützt. Als Mentoring-Anlass wird in erster Linie die Erkennung von mentaler Ermüdung untersucht, wobei Methoden der Psychologie zur Erkennung und Induktion ebendieser genutzt werden. Dabei werden im Rahmen einer Vorstudie Eye-Tracking Daten gesammelt, die anschließend von den Mustererkennungsalgorithmen Stützvektormaschine, Random Forest und künstlichem neuronalen Netz ausgewertet werden. Die Ergebnisse zeigen, dass die Erkennung von mentaler Ermüdung anhand der verwendeten Methodiken möglich ist. Zusätzlich wird ein Toolkit entwickelt, um die beschriebenen Prozesse zu automatisieren und die Einbindung in ein virtuelles Mentoring-System zu vereinfachen.:Kurzfassung, Abstract Selbständigkeitserklärung Vorwort Abkürzungsverzeichnis 1 Einführung 1.1 Motivation 1.2 Zielsetzung 2 Theoretische Grundlagen 2.1 Grundlagen des Eye-Trackings 2.1.1 Grundbegriffe und Charakteristiken des Eye-Trackings 2.1.2 Arten des Eye-Trackings 2.1.3 Wichtige Algorithmen 2.2 Grundlagen der Mustererkennung 2.2.1 Vorverarbeitung 2.2.2 Merkmalsextraktion und Auswahl 2.2.3 Klassifikation und Beurteilung 2.3 Grundlagen zu mentaler Ermüdung 2.3.1 Definition 2.3.2 Abgrenzung 3 Stand der Forschung 3.1 Pupil Invisible 3.2 Erkennung von mentaler Ermüdung 3.3 Einordnung 4 Methodik und Implementierung 4.1 Vorstudie 4.1.1 Sitzungsskript 4.1.2 Einarbeitung 4.2 Datenvorverarbeitung 4.2.1 Pistol-Framework 4.2.2 Verarbeitung der Rohdaten 4.2.3 Problemspezifische Merkmalserzeugung 4.3 Klassifikationsalgorithmen 4.3.1 Optimierung 4.3.2 Klassifikation mit künstlichen neuronalen Netzen 4.3.3 Auswertung 4.4 Toolkit 5 Ergebnisse 5.1 Vorstudie 5.2 Auswahl der Merkmale 5.3 Klassifikation 6 Diskussion 7 Zusammenfassung und Ausblick 7.1 Zusammenfassung 7.2 Ausblick Abbildungsverzeichnis Tabellenverzeichnis Literaturverzeichnis Anhang A.1 Tabellen A.1.1 Pearson und Spearman Korrelationstests (vollständig) A.2 Sitzungsskript A.2.1 Ablauf A.2.2 Durchzuführende Aufgaben / This thesis investigates how data from the eye-tracking glasses Pupil Invisible can be used to detect mentoring occasions using pattern recognition methods. The work is part of the research of a virtual mentoring system that supports students in completing online learning tasks on the OPAL learning platform. As a mentoring occasion, the detection of mental fatigue is primarily investigated, using methods from psychology for the detection and induction of just that. In this regard, eye-tracking data is collected as part of a preliminary study, which is then evaluated by the support vector machine, random forest and artificial neural network pattern recognition algorithms. The results show that the detection of mental fatigue is possible based on the methodologies used. In addition, a toolkit is developed to automate the described processes to facilitate their incorporation into a virtual mentoring system.:Kurzfassung, Abstract Selbständigkeitserklärung Vorwort Abkürzungsverzeichnis 1 Einführung 1.1 Motivation 1.2 Zielsetzung 2 Theoretische Grundlagen 2.1 Grundlagen des Eye-Trackings 2.1.1 Grundbegriffe und Charakteristiken des Eye-Trackings 2.1.2 Arten des Eye-Trackings 2.1.3 Wichtige Algorithmen 2.2 Grundlagen der Mustererkennung 2.2.1 Vorverarbeitung 2.2.2 Merkmalsextraktion und Auswahl 2.2.3 Klassifikation und Beurteilung 2.3 Grundlagen zu mentaler Ermüdung 2.3.1 Definition 2.3.2 Abgrenzung 3 Stand der Forschung 3.1 Pupil Invisible 3.2 Erkennung von mentaler Ermüdung 3.3 Einordnung 4 Methodik und Implementierung 4.1 Vorstudie 4.1.1 Sitzungsskript 4.1.2 Einarbeitung 4.2 Datenvorverarbeitung 4.2.1 Pistol-Framework 4.2.2 Verarbeitung der Rohdaten 4.2.3 Problemspezifische Merkmalserzeugung 4.3 Klassifikationsalgorithmen 4.3.1 Optimierung 4.3.2 Klassifikation mit künstlichen neuronalen Netzen 4.3.3 Auswertung 4.4 Toolkit 5 Ergebnisse 5.1 Vorstudie 5.2 Auswahl der Merkmale 5.3 Klassifikation 6 Diskussion 7 Zusammenfassung und Ausblick 7.1 Zusammenfassung 7.2 Ausblick Abbildungsverzeichnis Tabellenverzeichnis Literaturverzeichnis Anhang A.1 Tabellen A.1.1 Pearson und Spearman Korrelationstests (vollständig) A.2 Sitzungsskript A.2.1 Ablauf A.2.2 Durchzuführende Aufgaben

No description available.

No description available.

No description available.

No description available.

No / In this paper, we investigate how controlled changes to image properties and orientation affect eye movements for repeated viewings of images of natural scenes. We make changes to images by manipulating low-level image content (such as luminance or chromaticity) and/or inverting the image. We measure the effects of these manipulations on human scanpaths (the spatial and chronological path of fixations), additionally comparing these effects to those predicted by a widely used saliency model (L. Itti & C. Koch, 2000). Firstly we find that repeated viewing of a natural image does not significantly modify the previously known repeatability (S. A. Brandt & L. W. Stark, 1997; D. Noton & L. Stark, 1971) of scanpaths. Secondly we find that manipulating image features does not necessarily change the repeatability of scanpaths, but the removal of luminance information has a measurable effect. We also find that image inversion appears to affect scene perception and recognition and may alter fixation selection (although we only find an effect on scanpaths with the additional removal of luminance information). Additionally we confirm that visual saliency as defined by L. Itti and C. Koch's (2000) model is a poor predictor of real observer scanpaths and does not predict the small effects of our image manipulations on scanpaths.

The inherited form of primary open angle glaucoma, a disorder characterized by increased intraocular pressure and retina degeneration, is linked to mutations in the olfactomedin (OLF) domain of the myocilin gene. Disease-causing myocilin variants accumulate within trabecular meshwork cells instead of being secreted to the trabecular extracellular matrix thought to regulate aqueous humor flow and control intraocular pressure. Like other diseases of protein misfolding, we hypothesize myocilin toxicity originates from defects in protein biophysical properties. In this thesis, the first preparative recombinant high-yield expression and purification system for the C-terminal OLF domain of myocilin (myoc-OLF) is described. To determine the relative stability of wild-type (WT) and mutant OLF domains, a fluorescence thermal stability assay was adapted to provide the first direct evidence that mutated OLF is folded but less thermally stable than WT. In addition, mutant myocilin can be stabilized by chemical chaperones. Together, this work provides the first quantitative demonstration of compromised stability among identified OLF variants and placing myocilin glaucoma in the context of other complex diseases of protein misfolding. Subsequent investigations into the biophysical properties of WT myoc-OLF provide insight into its structure and function. In particular, myoc-OLF is stable in the presence of glycosaminoglycans (GAGs), as well as over a wide pH range in buffers with functional groups reminiscent of such GAGs. Myoc-OLF contains significant â-sheet and â-turn secondary structure as revealed by circular dichroism analysis. At neutral pH, thermal melts indicate a highly cooperative transition with a melting temperature of ~55°C. A compact core structural domain of OLF was identified by limited proteolysis and consists of approximately residues 238-461, which retains the single disulfide bond and is as stable as the full myoc-OLF construct. This construct also is capable of generating 3D crystals for structure determination. This data, presented in Chapter 3, inform new testable hypotheses for interactions with specific trabecular extracellular matrix components. To gain further insight into the biological function of myoc-OLF, a facile fluorescence chemical stability assay was designed to identify possible ligands and drug candidates. In the assay described in Chapter 4, the target protein is initially destabilized with a chemical denaturant and is tested for re-stabilization upon the addition of small molecules. The assay requires no prior knowledge of the structure and/or function of the target protein, and it is amendable to high-throughput screening. Application of the assay using a library of 1,280 compounds revealed 14 possible ligands and drug candidates for myoc-OLF that may also generate insights into myoc-OLF function. Due to the high â-sheet content of monomeric myoc-OLF and presence of an aggregated species upon myoc-OLF purification, the ability of myoc-OLF to form amyloid fibrils was suspected and verified. The fibril forming region was confirmed to reside in the OLF domain of myocilin. Kinetic analyses of fibril formation reveal a self-propagating process common to amyloid. The presence of an aggregated species was confirmed in cells transfected with WT myocilin, but to a greater extent in cells transfected with P370L mutant myocilin. Both cell lines stained positive for amyloid. Taken together, these results provide further insights into the structure of myocilin and suggest a new hypothesis for glaucoma pathogenesis. Finally, in a related study, small molecule drug candidates were investigated to treat acid â-glucosidase (GCase), the deficient lysosomal enzyme in Gaucher disease, another protein conformational disorder. Three new GCase active-site directed 3,4,5,6-tetrahydroxylazepane inhibitors were synthesized that exhibit half inhibitory concentrations (IC50) in the low millimolar to low micromolar range. Although the compounds thermally stabilize GCase at pH 7.4, only one of the synthesized analogs exhibits chaperoning activity under typical assay conditions. This successful pharmacological chaperone is also one in which GCase is in its proposed active conformation as revealed by X-ray crystallography. Probing the plasticity of the active-site of GCase offers additional insight into possible molecular determinants for an effective small molecule therapy for GD.

The human eye is a complex optical system comprised of many components. The crystalline lens, an optical component with a gradient index (GRIN), is perhaps the least understood as it is situated inside the eye and as a result is difficult to characterize. Its complex nonlinear structure is not easily measured and consequently not easily modeled. Presently several models of the GRIN structure exist describing the average performance of crystalline lenses. These models, however, do not accurately describe the performance of crystalline lenses on an individual basis and a more accurate individual eye model based on anatomical parameters is needed. This thesis proposes an anatomically correct, individually customizable crystalline lens model. This is an important tool and is needed both for research on the optical properties of human eyes and to diagnose and plan the treatment of optically based visual problems, such as refractive surgery planning. The lens model consisted of an interior GRIN with a constant refractive index core. The anterior and posterior surface was described by conic sections. To realize this eye model, the optical and biometric properties of mammalian lenses were measured and the correlation relationships between these measurements were used to simplify the model down to one fitting parameter which controls the shape of the GRIN. Using this data, an anatomically correct individualizable model of the lens was successfully realized with varying parameters unique to each lens. Using this customizable lens model, customizable human eye models based on measurements of the entire human eye can be realized.