658 research outputs found

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

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    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

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    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

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    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

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    This study investigates the role and value of distributed rainfall for the runoff generation of a mesoscale catchment (20 km2^{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

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    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

    Sources of power and conflict handling styles of supervisors

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    In order to fill the gap in existing research on the topic, this study was undertaken to establish whether a relationship exists between five sources of power and five conflict handling styles. A theoretical study regarding the concepts of power and conflict was undertaken. In the empirical study these variables were measured using the Power Base Index and Thomas-Kilmann Conflict MODE questionnaires. Reward power was significantly related to the competing and avoiding conflict handling styles; expert power was significantly related to the compromising style; and legitimate power was significantly related to the collaborating conflict handling style. The research contributes towards a better understanding of power and conflict in organisations and in supervisors' day-to-day management. However, the results indicate the importance of wider, more sophisticated research.Industrial and Organisational PsychologyM. Com. (Industrial Psychology
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