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Method for determination of beech veneer behavior under compressive load using the short‑span compression test
No full textA method for the determination of mechanical properties under compressive load is presented in this study. The short-span compression test is standardized for paper-based materials and was adapted for veneer in this study. Rotary cut veneer and solid wood of European beech (Fagus sylvatica L.) was tested parallel and transversal to fiber direction. The veneer thickness was varied between 1 and 3 mm. The mechanical properties Young’s modulus, Poisson’s ratio, yield point and compressive strength were measured. The results show that the correct determination of Poisson's ratio depends on the veneer thickness as well as on the fiber direction. For veneer with a thickness of at least 3 mm, it is suitable in fiber direction, but not transversal to the fiber direction. The comparison of the mechanical properties between veneer and solid wood confirms that the lathe checks mainly influence the veneer properties transversal to the fiber direction
Wolfgang Petke, Aufsätze zur Pfarreigeschichte in Mittelalter und Früher Neuzeit. (Studien zur Kirchengeschichte Niedersachsens, Bd. 52.) Göttingen, V&R unipress 2020
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Diagnostic Specificity of Two Dengue Virus IgG ELISAs after Yellow Fever and Japanese Encephalitis Virus Vaccination
No full textDengue virus (DENV) antibody assays frequently cross-react with sera from individuals who have been infected with or vaccinated against related flaviviruses. The goal of this study was to determine the specificity of two DENV ELISAs with sera from individuals vaccinated against yellow fever virus (YFV) and Japanese encephalitis virus (JEV). The Panbio and the Novatec Dengue IgG ELISAs
were tested with sera obtained 3–4 weeks or 0.5–6 years after YFV or JEV vaccination and the diagnostic specificity of the assays was determined. As controls, the sera were tested using DENV, YFV, JEV, Zika and West Nile virus neutralization assays. The diagnostic specificity of the Panbio and the Novatec
ELISA with sera from YFV-vaccinated subjects was 98.2% and 88.2%, respectively. Cross-reactions were rare in the first 4 weeks despite high YFV-neutralizing antibody titers and were mostly found later. The specificity of the Panbio and Novatec assays with sera from JEV-vaccinated individuals was 100% and
92.9%. Cross-reactions occurred in the early time period after vaccination. The measurement values of the two ELISAs correlated strongly. Thus, the Panbio ELISA showed higher diagnostic specificity and may be suitable for seroprevalence studies in areas with high disease prevalence
Enhancing Learning and Assessment in Computer Science Education
No full textThe focus of this thesis is on techniques for providing feedback and scaffolding in computer science education to enhance student motivation and engagement in programming language learning. Based on initial research on the use of gamification as a feedback mechanism, research gaps relating to adaptive and self-paced learning strategies are identified. In addition, approaches for the generation of single-choice examination questions and programming tasks were developed to tackle challenges arisen during the thesis. These developments, in turn, created the need to enhance formative quality assurance supported by generative artificial intelligence.
The main objective of this thesis is on how to improve student motivation and engagement in programming education through the integration of programming-related tasks, scaffolding techniques and other supportive strategies. The research addresses the impact of digital tools and platforms on the teaching and learning processes and examines their impact on teachers, examiners and students. To achieve these objectives, a combination of research methods was used, including a systematic literature review, grounded theory and design science approaches, supported by prototyping and experimental evaluations.
The main contributions are a literature study that identifies trends and gaps in the use of gamified feedback in computer science education. In addition, the creation of a template- based task generator for producing varied exam questions is presented. Subsequently, the generator approach is applied to programming tasks and a framework is developed for adaptive programming tasks, that takes into account the student knowledge about task solution and problem context. This is followed by an experimental study to test the usefulness of created hints based on the framework, as well as the role of computational thinking and motivational factors in programming success. Finally, an approach is presented that examines the ability of generative artificial intelligence to be used for formative quality assurance for exam question.:Contents II
List of Figures III
Acronyms IV
1 Introduction 1
1.1 Motivation and Problem Statement . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Research Objectives and Questions . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Research Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Research Area Overview and Interdisciplinary Context . . . . . . . . . . . 8
1.4.1 Computer Science Education . . . . . . . . . . . . . . . . . . . . . 8
1.4.2 Computational Thinking . . . . . . . . . . . . . . . . . . . . . . . 10
1.4.3 Task Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.4 Individualized Programming Tasks . . . . . . . . . . . . . . . . . 13
1.4.5 Gamification, Gameful Learning and Gameful Feedback . . . . . . 14
1.4.6 AI in Educational Settings . . . . . . . . . . . . . . . . . . . . . . 17
1.5 Contextualization and Connection between Individual Research Papers . . . 18
1.6 Outline of the Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2 Literature Study 22
2.1 A Systematic Literature Review of Gameful Feedback in Computer Science
Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3 Single-Choice Generator 30
3.1 Template-Based Generator for Single-Choice Questions . . . . . . . . . . . 30
4 Feature-based task design 49
4.1 A Didactic Framework for Generating Individual Programming Tasks . . . 49
5 Experiment 61
5.1 Hint Levels for the Solution Space: Exploring the Connection between Com-
putational Thinking and Programming . . . . . . . . . . . . . . . . . . . . 61
6 Formative QA with AI 91
6.1 Assisting Quality Assurance of Examination Tasks: Using a GPT Model and
Bayesian Testing for Formative Assessment . . . . . . . . . . . . . . . . . 91
7 Conclusion and Outlook 127
7.1 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
7.2 Recommendations for Teaching and Assessment . . . . . . . . . . . . . . 130
7.3 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Bibliography V
Wissenschaftlicher Werdegang XXXI
Selbstständigkeitserklärung XXXI
Optical coherence tomography for in vivo imaging of human oral lichen planus
No full textIt is of large importance to identify abnormalities and pathologies of the oral mucosa. In this perspective, the use of non-invasive optical techniques such as OCT provides the opportunity to complement common diagnostics. Especially in cases of recurrent or multiple lesions, OCT diagnosing promises a thorough and, if necessary, repeated assessment of the oral mucosa without the drawbacks of invasive procedures. For this reason, the number of studies on in vivo OCT examination of suspicious oral mucosal lesions is continually increasing. At the same time, there are only a few studies focusing on imaging pathologically altered oral mucosa. Against this background, the aim of this work was to characterize pathological oral mucosa with the clinical diagnosis of OLP in various areas of the oral cavity and additionally diagnose it using OCT imaging. An endoscopic in vivo OCT examination, in addition to conventional diagnostics, was conducted on 22 adult patients. The examination involved three measurement points, but only two were included for further analysis: the pathological center and the transition to healthy mucosa. Subsequently, image analysis was performed based on qualitative criteria to assess the oral mucosa. The parameters for examining OCT scans included EP thickness, delineation/visibility of the basement membrane, EP reflectivity, LP reflectivity and visible vascular network in the lamina propria. For classified OLP in general, the structural changes in the oral mucosa were compared to the normal state and the parameters of healthy oral mucosa served as a basis for determining the altered morphology in OCT, depending on the clinical classification of OLP. This made it possible to derive OLP-specific features in OCT. The goal of this dissertation was also to relate in vivo depth-resolution cross-sectional image information from OCT to the clinical diagnosis and compare certain parameters of different OLP forms. The transition from a normal to a pathological finding is sometimes clinically challenging to define, as is the appropriate area for a biopsy in an extensive and widespread oral lesion or alteration. In the future, non-invasive optical biopsy could be helpful in this regard. In this case series, as a first step, OCT cross-sectional images of central and peripheral areas of various types and subtypes of OLP were non-invasively captured and correlated with visual clinical findings and, if available, with histopathology. By identifying and describing OLP-specific features in OCT cross-sections for different forms of OLP, we establish a foundation for the non-invasive differentiation of suspicious dysplastic lesions from OLP and other pathology was established. This may improve biopsy sampling in the future and ensure reliable histopathological assessment. The next step is to further investigate the proposed OCT technology in clinical studies with a larger number of cases, obtaining robust data on the sensitivity and specificity of OCT for distinguishing various forms of OLP, as well as for distinguishing dysplastic changes and squamous cell carcinomas