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Suche nach „[2018]“ hat 275 Publikationen gefunden
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    GesundEuropan Campus Rottal-Inn

    Zeitschriftenartikel

    E. Faiola, I. Meyhöfer, M. Steffens, Anna-Maria Kasparbauer, V. Kumari, U. Ettinger

    Combining Trait and State Model Systems of Psychosis: The Effect of Sleep Deprivation on Cognitive Functions in Schizotypal Individuals

    Psychiatry Research, vol. 270, no. December, pp. 639-648

    2018

    DOI: 10.1016/j.psychres.2018.10.033

    Abstract anzeigen

    Model systems of psychosis play an important role in pathophysiology and drug development research. Schizotypal individuals display similar cognitive impairments as schizophrenia patients in several domains. Therefore, schizotypy may be interpreted as a trait model system of psychosis. In addition, experimentally controlled sleep deprivation is a putative state psychosis model that evokes subclinical psychosis-like states. We aimed to further validate these model systems by examining them in relation to central cognitive biomarkers of schizophrenia. Most of all, we were interested in investigating, for the first time, effects of their combination on cognitive function. Healthy subjects with high (N = 17) or low (N = 19) levels of schizotypy performed a cognitive task battery after one night of normal sleep and after 24 h of sleep deprivation. Sleep deprivation impaired performance in the go/nogo and n-back tasks relative to the normal sleep control condition. No differences between groups or interactions of group with sleep condition were found. The role of sleep deprivation as a model of psychosis is thus supported to some extent by impairments in inhibitory control. However, classical measures of cognition may be less able to detect deficits in schizotypy, in line with evidence of more basic information processing dysfunctions in schizotypy.

    GesundEuropan Campus Rottal-Inn

    Zeitschriftenartikel

    M. Steffens, C. Neumann, Anna-Maria Kasparbauer, B. Becker, B. Weber, M. Mehta, R. Hurlemann, U. Ettinger

    Effects of ketamine on brain function during response inhibition

    Psychopharmacology, vol. 235, pp. 3559-3571

    2018

    DOI: 10.1007/s00213-018-5081-7

    Abstract anzeigen

    Introduction The uncompetitive N-methyl-D-aspartate (NMDA) receptor (NMDAR) antagonist ketamine has been proposed to model symptoms of psychosis. Inhibitory deficits in the schizophrenia spectrum have been reliably reported using the antisaccade task. Interestingly, although similar antisaccade deficits have been reported following ketamine in non-human primates, ketamine-induced deficits have not been observed in healthy human volunteers. Methods To investigate the effects of ketamine on brain function during an antisaccade task, we conducted a double-blind, placebo-controlled, within-subjects study on n = 15 healthy males. We measured the blood oxygen level dependent (BOLD) response and eye movements during a mixed antisaccade/prosaccade task while participants received a subanesthetic dose of intravenous ketamine (target plasma level 100 ng/ml) on one occasion and placebo on the other occasion. Results While ketamine significantly increased self-ratings of psychosis-like experiences, it did not induce antisaccade or prosaccade performance deficits. At the level of BOLD, we observed an interaction between treatment and task condition in somatosensory cortex, suggesting recruitment of additional neural resources in the antisaccade condition under NMDAR blockage. Discussion Given the robust evidence of antisaccade deficits in schizophrenia spectrum populations, the current findings suggest that ketamine may not mimic all features of psychosis at the dose used in this study. Our findings underline the importance of a more detailed research to further understand and define effects of NMDAR hypofunction on human brain function and behavior, with a view to applying ketamine administration as a model system of psychosis. Future studies with varying doses will be of importance in this context.

    GesundEuropan Campus Rottal-Inn

    Zeitschriftenartikel

    A. Kupferberg, M. Iacoboni, V. Flanagin, M. Huber, Anna-Maria Kasparbauer, T. Baumgartner, G. Hasler, F. Schmidt, C. Borst, S. Glasauer

    Fronto-parietal Coding of Goal-Directed Actions Performed by Artificial Agents

    Human Brain Mapping, vol. 33, no. 3, pp. 1145-1162

    2018

    DOI: 10.1002/hbm.23905

    Abstract anzeigen

    With advances in technology, artificial agents such as humanoid robots will soon become a part of our daily lives. For safe and intuitive collaboration, it is important to understand the goals behind their motor actions. In humans, this process is mediated by changes in activity in fronto-parietal brain areas. The extent to which these areas are activated when observing artificial agents indicates the naturalness and easiness of interaction. Previous studies indicated that fronto-parietal activity does not depend on whether the agent is human or artificial. However, it is unknown whether this activity is modulated by observing grasping (self-related action) and pointing actions (other-related action) performed by an artificial agent depending on the action goal. Therefore, we designed an experiment in which subjects observed human and artificial agents perform pointing and grasping actions aimed at two different object categories suggesting different goals. We found a signal increase in the bilateral inferior parietal lobule and the premotor cortex when tool versus food items were pointed to or grasped by both agents, probably reflecting the association of hand actions with the functional use of tools. Our results show that goal attribution engages the fronto-parietal network not only for observing a human but also a robotic agent for both self-related and social actions. The debriefing after the experiment has shown that actions of human-like artificial agents can be perceived as being goal-directed. Therefore, humans will be able to interact with service robots intuitively in various domains such as education, healthcare, public service, and entertainment.

    DigitalAngewandte Informatik

    Zeitschriftenartikel

    J. Li, Wang, J., Marcus Barkowsky, P. Callet

    Exploring the effects of subjective methodology on assessing visual discomfort in immersive multimedia

    Electronic Imaging, Human Vision and Electronic Imaging

    2018

    DOI: 10.2352/ISSN.2470-1173.2018.14.HVEI-527

    Abstract anzeigen

    Visual discomfort is an important factor that influences viewing experience in immersive multimedia, for example, 3DTV and VR. With the added value of depth, the novel perceptual experience, visual discomfort is not an easy task for observers to evaluate. In this study, we investigate how the subjective methodology affects the test results in 3DTV condition. Two subjective visual discomfort experiments were conducted. One used the Pair Comparison (PC) method and the other used the Absolute-Category Rating (ACR) method. The results demonstrated that PC method had more powerful discriminability. For a difficult perceptualrelated tasks, such as visual discomfort in our study, PC was more easy to understand and conduct for the observers which led to reliable results. It also showed some very important but usually ignored conclusions on the subjective experiment, i.e., for measuring the perceived visual discomfort, the observer\textquoterights judgment behavior might be affected by the test methodology.

    DigitalAngewandte Informatik

    Zeitschriftenartikel

    A. Aldahdooh, E. Masala, G. Wallendael, Marcus Barkowsky

    Framework for reproducible objective video quality research with case study on PSNR implementations

    Digital Signal Processing, vol. 77, no. June, pp. 195-206

    2018

    DOI: 10.1016/j.dsp.2017.09.013

    Abstract anzeigen

    Reproducibility is an important and recurrent issue in objective video quality research because the presented algorithms are complex, depend on specific implementations in software packages or their parameters need to be trained on a particular, sometimes unpublished, dataset. Textual descriptions often lack the required detail and even for the simple Peak Signal to Noise Ratio (PSNR) several mutations exist for images and videos, in particular considering the choice of the peak value and the temporal pooling. This work presents results achieved through the analysis of objective video quality measures evaluated on a reproducible large scale database containing about 60,000 HEVC coded video sequences. We focus on PSNR, one of the most widespread measures, considering its two most common definitions. The sometimes largely different results achieved by applying the two definitions highlight the importance of the strict reproducibility of the research in video quality evaluation in particular. Reproducibility is also often a question of computational power and PSNR is a computationally inexpensive algorithm running faster than realtime. Complex algorithms cannot be reasonably developed and evaluated on the abovementioned 160 hours of video sequences. Therefore, techniques to select subsets of coding parameters are then introduced. Results show that an accurate selection can preserve the variety of the results seen on the large database but with much lower complexity. Finally, note that our SoftwareX accompanying paper presents the software framework which allows the full reproducibility of all the research results presented here, as well as how the same framework can be used to produce derived work for other measures or indexes proposed by other researchers which we strongly encourage for integration in our open framework.

    DigitalAngewandte Informatik

    Zeitschriftenartikel

    A. Aldahdooh, Marcus Barkowsky, P. Le Callet

    Proof-of-concept: role of generic content characteristics in optimizing video encoders

    Multimedia Tools and Applications, vol. 77, pp. 16069-16097

    2018

    DOI: 10.1007/s11042-017-5180-1

    Abstract anzeigen

    The influence of content characteristics on the efficiency of redundancy and irrelevance reduction in video coding is well known. Each new standard in video coding includes additional coding tools that potentially increase the complexity of the encoding process in order to gain further rate-distortion efficiency. In order to be versatile, encoder implementations often neglect the content dependency or they optimize the encoding complexity on a local scale, i.e. on a single frame or on the coding unit level without being aware of the global content type. In this contribution, an analysis is presented which coding tool settings of the recent High Efficiency Video Coding (HEVC) standard are most efficient for a given content type when balancing rate-distortion against computational complexity measured in encoding time. The content type is algorithmically determined, leading to a framework for rate-distortion-complexity based encoder parameter decision for any given video sequence. The implementability is demonstrated using a set of 35 Ultra-HD (UHD) sequences. The performance results and evaluations show that the encoding parameters may be predicted to optimize the video coding. For instance, predicting motion search range achieves complexity reduction of 36% on average when HEVC reference HM is used at a cost of bitrate (2%). When another HEVC coding standard software, x265, is used to predict the coding unit (CU) size, there is a reduction of 20% in bitrate and of 8% in distortion but there is a reduction of 6% in execution time.

    DigitalAngewandte Informatik

    Zeitschriftenartikel

    A. Aldahdooh, E. Masala, G. Wallendael, Marcus Barkowsky

    Reproducible research framework for objective video quality measures using a large-scale database approach

    SoftwareX, vol. 8, no. July-December, pp. 64-68

    2018

    DOI: 10.1016/j.softx.2017.09.004

    Abstract anzeigen

    This work presents a framework to facilitate reproducibility of research in video quality evaluation. Its initial version is built around the JEG-Hybrid database of HEVC coded video sequences. The framework is modular, organized in the form of pipelined activities, which range from the tools needed to generate the whole database from reference signals up to the analysis of the video quality measures already present in the database. Researchers can re-run, modify and extend any module, starting from any point in the pipeline, while always achieving perfect reproducibility of the results. The modularity of the structure allows to work on subsets of the database since for some analysis this might be too computationally intensive. To this purpose, the framework also includes a software module to compute interesting subsets, in terms of coding conditions, of the whole database. An example shows how the framework can be used to investigate how the small differences in the definition of the widespread PSNR metric can yield very different results, discussed in more details in our accompanying research paper Aldahdooh et al. (0000). This further underlines the importance of reproducibility to allow comparing different research work with high confidence. To the best of our knowledge, this framework is the first attempt to bring exact reproducibility end-to-end in the context of video quality evaluation research.

    DigitalAngewandte Informatik

    Zeitschriftenartikel

    K. Brunnström, Marcus Barkowsky

    Statistical quality of experience analysis: on planning the sample size and statistical significance testing

    Journal of Electronic Imaging, vol. 27, no. 5

    2018

    DOI: 10.1117/1.JEI.27.5.053013

    Abstract anzeigen

    This paper analyzes how an experimenter can balance errors in subjective video quality tests between the statistical power of finding an effect if it is there and not claiming that an effect is there if the effect is not there, i.e., balancing Type I and Type II errors. The risk of committing Type I errors increases with the number of comparisons that are performed in statistical tests. We will show that when controlling for this and at the same time keeping the power of the experiment at a reasonably high level, it is unlikely that the number of test subjects that are normally used and recommended by the International Telecommunication Union (ITU), i.e., 15 is sufficient but the number used by the Video Quality Experts Group (VQEG), i.e., 24 is more likely to be sufficient. Examples will also be given for the influence of Type I error on the statistical significance of comparing objective metrics by correlation. We also present a comparison between parametric and nonparametric statistics. The comparison targets the question whether we would reach different conclusions on the statistical difference between the video quality ratings of different video clips in a subjective test, based on the comparison between the student T-test and the Mann‐Whitney U-test. We found that there was hardly a difference when few comparisons are compensated for, i.e., then almost the same conclusions are reached. When the number of comparisons is increased, then larger and larger differences between the two methods are revealed. In these cases, the parametric T-test gives clearly more significant cases, than the nonparametric test, which makes it more important to investigate whether the assumptions are met for performing a certain test.

    Angewandte Wirtschaftswissenschaften

    Internetdokument

    M. Christl, Wolfgang Nagl

    Arbeitssuchengeld

    Paper. Agenda Austria

    2018

    Angewandte Wirtschaftswissenschaften

    Internetdokument

    Wolfgang Nagl, L. Sustala

    Arbeitszeitflexibilisierung - Eine Einordnung der Agenda Austria

    Policy Brief. Agenda Austria

    2018

    Angewandte Wirtschaftswissenschaften

    Zeitschriftenartikel

    Wolfgang Nagl, F. Schellhorn

    Pensionen sichern wie Schweden

    Gesellschaft & Politik (Zeitschrift für soziales und wirtschaftliches Engagement, vol. 54, no. 1, pp. 49-53

    2018

    DigitalAngewandte WirtschaftswissenschaftenTC Grafenau

    Zeitschriftenartikel

    Michael Scholz, J. Schnurbus, H. Haupt, V. Dorner, A. Landherr, F. Probst

    Dynamic effects of user- and marketer-generated content on consumer purchase behavior: Modeling the hierarchical structure of social media websites

    Decision Support Systems, vol. 113, no. September, pp. 43-55

    2018

    DOI: 10.1016/j.dss.2018.07.001

    Abstract anzeigen

    User- and marketer-generated content items on social media platforms are supposed to have an impact on economic target variables, such as variables measuring consumers' purchase behavior. The position of each content item – and thus the impact on economic variables – changes with newly appearing items. We propose a hierarchy score to capture the dynamics of the content items on social media platforms. In order to mimic the reduced visibility of earlier content items, our hierarchy score computes the position of content items based on the number of text line equivalents of content items above a particular item. Employing the proposed hierarchy score in a dynamic regression framework for data of a large online store yields improved estimates and predictions compared to a variety of other models.

    DigitalMobilDEG-DLM2IQW

    Zeitschriftenartikel

    Andreas Gegenfurtner, Nina Schwab, Christian Ebner

    "There's no need to drive from A to B": Exploring the lived experience of students and lecturers with digital learning in higher education

    Bavarian Journal of Applied Sciences, vol. 4, no. 1, pp. 310-322

    2018

    DOI: 10.25929/bjas.v4i1.50

    Abstract anzeigen

    In vielen ländlichen Regionen weltweit nehmen Menschen den Bus oder das Auto, um zu Städten zu gelangen, in denen Bildungsangebote und Trainingsprogramme angeboten werden. In einer Zeit wachsender Digitalisierung werden Lernumgebungen und Weiterbildungen jedoch zunehmend auf Online-Plattformen zugänglich gemacht. Studierende haben so Zugang zu digitalem Lernmaterial oder können an technologiebasierten Veranstaltungen von jedem Ort weltweit partizipieren. Diese wachsende ubiquitäre Verfügbarkeit von Bildung ‒ zusammen mit einer geographischen Flexibilität, die Blended Learning in Form von LernCentern, Webkonferenzen und virtuellen Kursen ermöglicht ‒ reduziert die Notwendigkeit von (Auto-)Mobilität in vielen ländlichen Regionen. Der Zweck dieser Studie war, die Erfahrungen von nichttraditionellen Studierenden und deren Dozierenden hinsichtlich reduzierter mobiler Anforderungen zu explorieren. Basierend auf Gibsons Theory of Affordances und einem Forschungsinteresse in der narrativen Interpretation lebensumweltlicher Erfahrung berichtet die Studie qualitative Analysen von reflexivem Interviewmaterial, das beschreibt, wie Teilnehmende und Dozierende die flexiblen, ubiquitär verfügbaren, synchron und asynchron angebotenen Weiterbildungsangebote wahrnehmen. Implikationen der Studie werden diskutiert hinsichtlich Theorieentwicklung und der praktischen Implementierung digitaler Bildung für nicht-traditionelle Studierende in ländlichen Regionen.

    DigitalDEG-DLM2IQW

    Zeitschriftenartikel

    Andreas Gegenfurtner

    Testing the gender similarities hypothesis: differences in subjective task value and motivation to transfer training

    Human Resource Development International, vol. 7, no. 1, pp. 1-12

    2018

    DOI: 10.1080/13678868.2018.1449547

    Abstract anzeigen

    Are female and male trainees similar or different in their reaction to training programmes, specifically regarding their subjective task value and motivation to transfer? According to the gender similarities hypothesis, women and men are alike on most psychological variables. However, according to research in organizational behaviour, female and male employees differ on certain aspects, such as their job satisfaction and work identity. To test these two views on gender similarities and differences in the context of human resource development and training evaluation, the present study examined the extent to which gender moderated reactions to training. Based on the expectancy-value theory of motivation and self-determination theory, a web-based questionnaire was used to measure six training reactions: intrinsic value, attainment value, utility value, perceived relative cost, autonomous motivation to transfer, and controlled motivation to transfer. The results indicated that women and men differed in their ratings of attainment value but were similar for the remaining five reaction measures. These outcomes support the gender similarities hypothesis. The findings are discussed in terms of their theoretical implications for modelling gender effects in HRD research and their practical significance for promoting training effectiveness and transfer of training.

    DigitalDEG-DLM1IQW

    Buch (Monographie)

    Lina Spagert, Andreas Gegenfurtner, Gabriele Weng, Nina Schwab

    Bericht Begleitforschung zum Zertifikat Technische Betriebswirtschaft

    2018

    DigitalDEG-DLM1IQW

    Buch (Monographie)

    Andreas Gegenfurtner

    Schlussbericht Deggendorfer Distance-Learning Modell zur Stärkung der Region Niederbayern und der Förderung der akademischen Weiterbildung in ländlich strukturierten Gebieten (DEG-DLM)

    2018

    DigitalDEG-DLM1IQW

    Buch (Monographie)

    Christine Bomke, Andreas Gegenfurtner, Nina Schwab, Gabriele Weng

    Bericht zum berufsbegleitenden Weiterbildungszertifikat Supply Chain Management - Logistik und IT

    2018

    DigitalDEG-DLM1IQW

    Buch (Monographie)

    Christine Bomke, Andreas Gegenfurtner, Christine Resch, Gabriele Weng, Nina Schwab

    Bericht Begleitforschung zum Brückenkurs Physik 2017

    2018

    DigitalDEG-DLM1IQW

    Buch (Monographie)

    Christine Bomke, Andreas Gegenfurtner

    Anpassung der Lehrmethoden von Dozierenden in berufsbegleitenden Studiengängen und Weiterbildungszertifikaten an digitale Gegebenheiten

    2018