A Methodology for Adaptive Competence Assessment and Learning Path Creation in ISAC

In this paper a technique is presented how to realise adaptive competence assessment and the creation of adaptive learning paths for the ISAC system. ISAC is an intelligent tutoring system which supports the learner in solving problems in applied mathematics. It is able to monitor and support the learner in each calculation step. However, it does not support building user and competence profiles and sequencing of problems and learning objects based on the personal needs. Therefore, a technique has been developed and integrated with ISAC, which allows for assessing the competence profile of learners and creating learning paths adaptively based on the assessed competences. Development has been done in a modular way which also provides other features such as goal setting and visual feedback of skill gaps and progress

Tailoring Properties of Printed Field-Effect Transistors by Design and Material Changes

Due to the increasing digitalization in all areas of life and work, including digital signatures or even electronic feedbacks from single component parts or consumer articles, the question for new possibilities for quick and simple manufacturing of circuits arises. In this respect, also mass production of transistors, the core building units of electronic logics, has to be reconsidered in order to overcome the often complex production of silicon chips. In this scope, printing of electronic components has presented itself as a highly promising method within the recent years. Conductive paths, solar cells, or displays have already been integrated as printed electronics in manyfold industrial production processes. In contrast to this, so far, no reliable processes for printed transistors in an industrial scale have been established. Organic and inorganic semiconducting materials often have properties with diametral differences: while organic materials use to be p-type semiconductors and come up with simple processability and mechanical flexibility, inorganic systems tend to be n-type semiconductors, brittle and in need of high processing temperatures. These disadvantages of inorganic, especially oxidic semiconductors however are compensated by often severely better electronic properties and increased environmental stability. In order to achieve very low operation voltages while maintaining sufficiently high currents, it is recommended to realize channel polarization via electrolytes instead of dielectrics, as the formation of Helmholtz double layers allows for locally very high fields. By this, units can be operated at voltages typical for commercially available batteries. Within the scope of this work new and improved methods for the processing of printed field-effect transistors were successfully implemented, contributing to the development towards large-scale production of devices with predictable properties. Starting form planar field-effect transistors with displaced gates, three possibilities for improvements have been examined: a vertical geometry, doped channels and an alternative electrolyte. By changing from a planar to a vertical device geometry, channel lengths may become independent from the material printers’ resolutions and can be reduced to the thickness of the deposited films. By this lengths may be shrunk from a two-digit micron range to submicron values. As channel lengths are directly correlated with output currents, a severe improvement can be realized. However, in this case the channel must be porous in order to allow a large surface being covered by electrolyte. Within this work, a known system with an SnO2 channel could be improved by developing a simplified production method with quickly available materials, successfully resulting in a fully functional device. For reliably tailoring the central property of the threshold voltage, i.e., the gate voltage at which the channel changes from an insulating to a conducting state, on a per-device level, an In2O3 precursor ink with varying chromium doping has been developed. Through this doping, the threshold voltage could be changed linearly with the dopant concentration, however under severe loss in the output current. In a third experimental series, the usually applied composite solid polymer electrolyte has been replaced with Al2O3 . However, instead of a dielectric gating, a material with low density and many hydroxy functionalities acting as an electrolyte was created due to low temperatures during the atom layer deposition process. Depending on the humidity, the functionality of such transistors can be changed as the electrolytic properties are based on protons generated on the Al2O3 surface. Within this work, three alternatives for the production of inorganic field-effect transistors could be successfully shown and a contribution towards the further development of this technology was made

Optofluidic Force Induction as a Process Analytical Technology

Manufacturers of nanoparticle-based products rely on detailed information about critical process parameters, such as particle size and size distributions, concentration, and material composition, which directly reflect the quality of the final product. These process parameters are often obtained using offline characterization techniques that cannot provide the temporal resolution to detect dynamic changes in particle ensembles during a production process. To overcome this deficiency, we have recently introduced Optofluidic Force Induction (OF2i) for optical real-time counting with single particle sensitivity and high throughput. In this paper, we apply OF2i to highly polydisperse and multi modal particle systems, where we also monitor evolutionary processes over large time scales. For oil-in-water emulsions we detect in real time the transition between high-pressure homogenization states. For silicon carbide nanoparticles, we exploit the dynamic OF2i measurement capabilities to introduce a novel process feedback parameter based on the dissociation of particle agglomerates. Our results demonstrate that OF2i provides a versatile workbench for process feedback in a wide range of applications.Comment: 10 pages, 5 figure

The role and value of distributed precipitation data in hydrological models

This study investigates the role and value of distributed rainfall for the runoff generation of a mesoscale catchment (20 km$^{2}$). We compare four hydrological model setups and show that a distributed model setup driven by distributed rainfall only improves the model performances during certain periods. These periods are dominated by convective summer storms that are typically characterized by higher spatiotemporal variabilities compared to stratiform precipitation events that dominate rainfall generation in winter. Motivated by these findings, we develop a spatially adaptive model that is capable of dynamically adjusting its spatial structure during model execution. This spatially adaptive model allows the varying relevance of distributed rainfall to be represented within a hydrological model without losing predictive performance compared to a fully distributed model. Our results highlight that spatially adaptive modeling has the potential to reduce computational times as well as improve our understanding of the varying role and value of distributed precipitation data for hydrological models

Laser-Induced Evoked Potentials in the Brain after Nonperceptible Optical Stimulation at the Neiguan Acupoint: A Preliminary Report

We report on small but reproducible human cerebral evoked potentials after bilateral nonperceptible laser needle (658 nm, 40 mW, 500 μm, 1 Hz) irradiation of the Neiguan acupoint (PC6). The results which are unique in scientific literature were obtained in a 26-year-old female healthy volunteer within a joint study between the Medical University of Graz, the Karl-Franzens University of Graz, and the Graz University of Technology. The findings of the 32-channel evoked potential analysis indicate that exposure to laser needle stimulation with a frequency of 1 Hz can modulate the ascending reticular activating system. Further studies are absolutely necessary to confirm or refute the preliminary findings

Homeworks as an indicator of the quality of teaching

Ausgangspunkt für die Pilotstudie war die Annahme, daß Hausaufgabenprobleme zumindest auch Probleme des Unterrichts sind, aus dem heraus sie erteilt werden und in den sie wieder einmünden sollen. Dabei wurde versucht, Hausaufgabenprobleme explizit mit der Erfüllung bestimmter Lehrfunktionen, die sich u.a. bei Bloom (1976) finden, in Zusammenhang zu bringen. Die Ergebnisse der Pilotstudie lassen vermuten, daß a) tatsächlich ein Zusammenhang zwischen der Erfüllung bestimmter Lehrfunktionen durch den Lehrer und der Qualität der von den Schülern bearbeiteten Hausaufgaben besteht und daß b) Lehrer ihre Hausaufgabenpraxis schon nach einer kurzen theoriegeleiteten Unterweisung in erwünschter Richtung verändern und so zu einer Verbesserung der von den Schülern bearbeiteten Hausaufgaben beitragen können. Zudem zeigte sich, daß Lehrer ihre Lehrfunktionen im Kontext Hausaufgaben für verschiedene Schüler unterschiedlich erfüllen.This study argues that problems with homeworks usually are problems of teaching. In a pilot study a correlation between certain teaching functions and homework-problems was discussed and tested. The findings Support the assumed correlation and demonstrate that teachers can change their practice of giving homeworks and thus improve the homeworks of the Students