Geförderte Open-Access-Publikationen
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Publication Open Access Advances in biomimetic photoelectrocatalytic reduction of carbon dioxide(2022)Emerging photoelectrocatalysis (PEC) systems synergize the advantages of electrocatalysis (EC) and photocatalysis (PC) and are considered a green and efficient approach to CO2 conversion. However, improving the selectivity and conversion rate remains a major challenge. Strategies mimicking natural photosynthesis provide a prospective way to convert CO2 with high efficiency. Herein, several typical strategies are described for constructing biomimetic photoelectric functional interfaces; such interfaces include metal cocatalysts/semiconductors, small molecules/semiconductors, molecular catalysts/semiconductors, MOFs/semiconductors, and microorganisms/semiconductors. The biomimetic PEC interface must have enhanced CO2 adsorption capacity, preferentially activate CO2, and have an efficient conversion ability; with these properties, it can activate C=O bonds effectively and promote electron transfer and C-C coupling to convert CO2 to single-carbon or multicarbon products. Interfacial electron transfer and proton coupling on the biomimetic PEC interface are also discussed to clarify the mechanism of CO2 reduction. Finally, the existing challenges and perspectives for biomimetic photoelectrocatalytic CO2 reduction are presented.Source Type:Article578 170 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Annealing temperature-dependent induced supramolecular chiroptical response of copolymer thin films studied by pump-modulated transient circular dichroism spectroscopyCopolymer thin films showing induced supramolecular chirality are of considerable interest for optoelectronic applications such as organic light-emitting diodes. Here, we introduce a new helicene-like chiral additive with two octyloxy substituents which displays excellent chiral induction properties in an achiral polyfluorene copolymer, leading to a circular dichroism (CD) response of up to 10,000 mdeg. This chiral inducer also displays very good thermal stability, which enables us to perform an extended study on the induced chiroptical properties of the cholesteric copolymer thin films annealed at different temperatures in the range 140-260 °C. Starting from about 180 °C, a distinct change in the morphology of the CD-active film is observed by CD microscopy, from micrometre-size granular to extended CD-active regions, where the latter ones display skewed distributions of the dissymmetry parameter gabs. Broadband Müller matrix spectroscopy finds a pronounced CD and circular birefringence (CB) response and only weak linear dichroism (LD, LD') and linear birefringence (LB, LB'). Ultrafast transient CD spectroscopy with randomly polarised excitation reveals a clean mirror-image-type transient response, which shows a second-order decay of the S1 population due to singlet-singlet annihilation processes.Source Type:Article19 3 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Appetitive conditioning with pornographic stimuli elicits stronger activation in reward regions than monetary and gaming‐related stimuli(2024); ; ; ; ; Appetitive conditioning plays an important role in the development and maintenance of pornography-use and gaming disorders. It is assumed that primary and secondary reinforcers are involved in these processes. Despite the common use of pornography and gaming in the general population appetitive conditioning processes in this context are still not well studied. This study aims to compare appetitive conditioning processes using primary (pornographic) and secondary (monetary and gaming-related) rewards as unconditioned stimuli (UCS) in the general population. Additionally, it investigates the conditioning processes with gaming-related stimuli as this type of UCS was not used in previous studies. Thirty-one subjects participated in a differential conditioning procedure in which four geometric symbols were paired with either pornographic, monetary, or gaming-related rewards or with nothing to become conditioned stimuli (CS + porn, CS + game, CS + money, and CS−) in an functional magnetic resonance imaging study. We observed elevated arousal and valence ratings as well as skin conductance responses for each CS+ condition compared to the CS−. On the neural level, we found activations during the presentation of the CS + porn in the bilateral nucleus accumbens, right medial orbitofrontal cortex, and the right ventral anterior cingulate cortex compared to the CS−, but no significant activations during CS + money and CS + game compared to the CS−. These results indicate that different processes emerge depending on whether primary and secondary rewards are presented separately or together in the same experimental paradigm. Additionally, monetary and gaming-related stimuli seem to have a lower appetitive value than pornographic rewards.Source Type:Article1 19 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Approaches for the prediction of lead times in an engineer to order environment - a systematic review(2020); ; ; The interest of manufacturing companies in a sufficient prediction of lead times is continuouslyincreasing - especially in engineer to order environments with typically a large number of individual parts andcomplex production processes. A multitude of approaches have been proposed in the literature for predictinglead times considering different data and methods or algorithms from operations research (OR) and machinelearning (ML). In order to provide guidance at setting up prediction models and developing new approaches,a systematic review of the available approaches for predicting lead times is presented in this paper. Forty-twopublications were analyzed and synthetized: Based on a developed framework considering the used dataclass (e.g. product data or system status), the data origin (master data or real data) and the used methodand algorithm from OR and ML, the publications are classified. Based on the classification, a descriptiveanalysis is performed to identify common approaches in the existing literature as well as implications forfurther research. One result is, that mostly order data and the status of the production system are used forpredicting lead times whereas material data are used seldom. Additionally, ML approaches primarily useartificial neural networks and regression models for predicting lead times, while OR approaches use mainlycombinatorial optimization or heuristics. Furthermore, with increasing model complexity the use of realdata decreased. Thus, we identified as an implication for further research to set up a complex data modelconsidering material data, which uses real data as data origin.Source Type:Article396 868 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Are lovers ever one? Reconstructing the union theory of love(2018)Current analytical philosophies of romantic love tend to identify the essence of such love with one specific element, such as concern for the beloved person, valuing the beloved person or the union between the lovers. This paper will deal with different forms of the union theory of love which takes love to be the physical, psychic or ontological union of two persons. Prima facie, this theory might appear to be implausible because it has several contra-intuitive implications, and yet, I submit, it is more coherent and attractive than it seems to be. I shall distinguish three specific models and thereby offer a differentiated account of the union theory which has not previously been provided in the literature (1). I will claim that two of these models (the strong ontological model and the striving model) should be rejected (2). I shall then defend the third model (the moderate ontological model) against certain possible objections (3); but nevertheless, I shall conclude by showing how this model, too, faces further significant objections which ultimately expose the limits of the union theory of love (4). In conclusion, I will sketch the outlines of a non-reductive cluster theory of love.Source Type:Article267 76 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Automated set-up parameter estimation and result evaluation for SSI-Cov-OMA(2020); ; Traditionally, modal analysis and the extraction of modal parameters from vibration data is a process that requires a more or less extensive amount of manual interaction from setting input parameters up until finding the eigenfrequencies. The growing interest in continuously monitoring mechanical structures e.g. for automated damage detection methods has led to the development of many approaches to automate different aspects of modal analysis. In this context, the Covariance-driven Stochastic subspace identification (Cov-SSI) is a widely used method. The present paper provides an automated Cov-SSI algorithm combined with a peak-picking approach for the automatic determination of input parameters. In this regard, using the Prominence-parameter allows to examine the PSD by finding the most relevant peaks. The herein shown algorithm is currently suitable for systems with a limited number of sensors. Cov-SSI results are arranged in stability plots and interpreted using the hierarchical clustering method. By creating stability plots for a wide range of block rows a sensitivity analysis is used to find the optimal result based on the averaged standard deviation of damping of the clusters in every stability plot. A second aspect of this paper is comparing the common method for order reduction with a modified method described in [1], which preserves the orthogonality of the , and matrix of the singular value decomposition. Exemplary results on both methods are provided using simulated data (state-space, 3 DoF)Source Type:Article396 170 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Availability of a hybrid FSO/RF link while using the link’s diversity for packet scheduling(2018)Hybrid-free space optical and radio frequency wireless links are a way of providing reliable transport of real-time traffic in outdoor wireless environments. We consider a link layer protocol that assigns packets to each physical channel of such a hybrid link, which first attempts to send each packet over one of the links (the main link) and, if unsuccessful, sends the packet over the other link (the backup link). The hybrid link processes high-priority traffic by using the link layer protocol and additional (background) traffic at low priority over the backup link. In this setting, high-priority traffic can be transmitted at a rate as high as the maximum capacity of the main link, assuming that the backup link can compensate for main link capacity deterioration, with no need for reconfigurations aimed at adapting to changes in weather conditions, which is an advantage over other approaches. From the perspective of link availability for high-priority traffic, we compare our approach to using another protocol that does not require reconfigurations, which could be employed if the backup link is expected to have a constant transmission rate during the time interval of interest. For situations where both links can be represented by finite-state Markov models with states corresponding to channel bit error rates, as has been done in previous literature for radio frequency links and for free space optical links affected by strong atmospheric turbulence and Gaussian noise, we give a way to provide probabilistic quality of service guarantees for background traffic assuming that the high-priority traffic is insured to not exceed a given constant rate.Source Type:Article604 197 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Bayesian identification of structural coefficients in causal models and the causal false-positive risk of confounders and colliders in linear Markovian models(2022)Background: Causal inference has seen an increasing popularity in medical research. Estimation of causal effects from observational data allows to draw conclusions from data when randomized controlled trials cannot be conducted. Although the identification of structural causal models (SCM) and the calculation of structural coefficients has received much attention, a key requirement for valid causal inference is that conclusions are drawn based on the true data-generating model. Methods: It remains widely unknown how large the probability is to reject the true structural causal model when observational data from it is sampled. The latter probability – the causal false-positive risk – is crucial, as rejection of the true causal model can induce bias in the estimation of causal effects. In this paper, the widely used causal models of confounders and colliders are studied regarding their causal false-positive risk in linear Markovianmodels. A simulation study is carried out which investigates the causal false-positive risk in Gaussian linear Markovian models. Therefore, the testable implications of the DAG corresponding to confounders and colliders are analyzed from a Bayesian perspective. Furthermore, the induced bias in estimating the structural coefficients and causal effects is studied. Results: Results show that the false-positive risk of rejecting a true SCM of even simple building blocks like confounders and colliders is substantial. Importantly, estimation of average, direct and indirect causal effects can become strongly biased if a true model is rejected. The causal false-positive risk may thus serve as an indicator or proxy for the induced bias. Conclusion: While the identification of structural coefficients and testable implications of causal models have been studied rigorously in the literature, this paper shows that causal inference also must develop new concepts for controlling the causal false-positive risk. Although a high risk cannot be equated with a substantial bias, it is indicative of the induced bias. The latter fact calls for the development of more advanced risk measures for committing a causal type I error in causal inference.Source Type:Article323 56 - Some of the metrics are blocked by yourconsent settings
Publication Open Access bayest: an R-package for effect-size targeted Bayesian two-sample t-tests(2020)Typical situations in research include the comparison of two groups regarding a metric variable, in which case usually the two-sample t-test is applied. While common frequentist two-sample t-tests focus on the difference of means of both groups via a p-value, the quantity of interest in applied research most often is the effect size. Existing Bayesian alternatives of the two-sample t-test replace frequentist significance thresholds like the p-value with the Bayes factor, taking the same testing stance. The R package bayest implements a Markov-Chain-Monte-Carlo algorithm to conduct a Bayesian two-sample t-test which estimates the effect size between two groups, while also providing detailed visualization and analysis of all parameters of interest. Because of its focus on the ease of use and interpretability, clinicians and other users can run this t-test within a few lines of code and find out if differences between two groups are scientifically meaningful, instead of significant.Source Type:Article488 133 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Beats. Bauen. Lernen.(2022)At the beginning of the 1980s, beatmaking emerged within hip-hop culture in the U.S. - a musical practice based on the creative use of already existing sound material and practiced mainly in informal contexts. In the last 40 years, beatmaking has spread globally in close connection with developments in music and media technology and has become diversified in many ways. Especially in the field of popular music, beatmaking has set decisive impulses in musical-aesthetic and technical-practical respects. In his qualitative-empirical study, Chris Kattenbeck explores the question of what it means to act as an artistically competent beatmaker, what skills and knowledge are necessary for this, and how these are acquired and developed. In doing so, he provides fundamental insights into a hitherto hardly explored musical practice and the artistic strategies and techniques, aesthetic goals and ideas, forms of knowledge and learning practices associated with it. Among other things, it shows that certain prevailing understandings in music education - of music learning or music theory, for example - are inadequate to adequately capture beatmaking. Therefore, the study offers not least reason to question these understandings and to reconceptualize them in order to be able to deal appropriately with the diversity of musical practices in the future.Source Type:Doctoral Thesis506 578