Publikationen
Suche nach „[2018]“ hat 288 Publikationen gefunden
Suchergebnis als PDFDigitalF: Europan Campus Rottal-Inn
Zeitschriftenartikel
A Generalized Evaluation Framework for Multimedia Recommender Systems
International Journal of Semantic Computing, vol. 12, no. 04, pp. 541-557
2018
DOI: 10.1142/S1793351X18500046
With the widespread availability of media technologies, such as real-time streaming, new Internet-of-Thing devices and smart phones, multimedia data are extensively increased and the big multimedia data rapidly spread over various social networks. This has created complexity and information overload for users to choose the suitable multimedia objects. Thus, different multimedia recommender systems have been emerging to help users find the useful multimedia objects that are possibly preferred by the user. However, the evaluation of these multimedia recommender systems is still in an ad-hoc stage. Given the distinct features of multimedia objects, the evaluation criteria adopted from the general recommender systems might not be effectively used to evaluate multimedia recommendations. In this paper, we therefore review and analyze the evaluation criteria that have been used in the previous multimedia recommender system papers. Based on the review, we propose a generalized evaluation framework to guide the researchers and practitioners to perform evaluations, especially user-centric evaluations, for multimedia recommender systems.
DigitalF: Europan Campus Rottal-Inn
Zeitschriftenartikel
Matthias Huber, S. Schüller, M. Stöckli, K. Wohlrabe
Maschinelles Lernen in der ökonomischen Forschung
ifo Schnelldienst (Institut für Wirtschaftsforschung, München), vol. 71, no. 7, pp. 50-53
2018
In der empirischen Wirtschaftsforschung steigt die Anzahl der Publikationen, die mit Methoden des maschinellen Lernens arbeiten. Dennoch scheint eine gewisse Skepsis zu bestehen. Ein Kritikpunkt ist, dass sich maschinelles Lernen zwar für Vorhersagen eignet, aber keine kausalen Zusammenhänge identifizieren kann. In den vergangenen Jahren hat sich die Forschung jedoch verstärkt mit diesem Problem auseinandergesetzt, und es wurden zahlreiche Fortschritte erzielt. Maschinelles Lernen hat daher das Potenzial, in Zukunft in der Wirtschaftsforschung an Bedeutung zu gewinnen.
NachhaltigF: Elektrotechnik und MedientechnikI: IQMA
Vortrag
Christoph Metzke, W. Lehermeier
Investigation of Soft Polymer Surfaces using Atomic Force Microscopy and Laser Scanning Microscopy
Applied Research Conference (ARC) 2018, Deggendorf
2018
NachhaltigF: Elektrotechnik und MedientechnikI: IQMA
Vortrag
W. Lehermeier, Christoph Metzke
Investigation of Local Thermal Properties of Carbon Fiber / Epoxy Composites by using Scanning Thermal Microscopy
Applied Research Conference (ARC) 2018, Deggendorf
2018
GesundF: Angewandte Gesundheitswissenschaften
Zeitschriftenartikel
A. Fringer, Mareike Hechinger, F. Wolfensberger, R. Steiner, W. Schnepp
Transitions as experienced by persons in palliative care circumstances and their families - a qualitative meta-synthesis
BMC Palliative Care, vol. 17, no. Article number 22, pp. 1-15
2018
DOI: 10.1186/s12904-018-0275-7
Background When receiving palliative care, patients and their families experience altered life situations in which they must negotiate challenges in daily life, increased care and new roles. With limited time, they also experience emotional changes that relate to their uncertain future. Transitions experienced in such situations are often studied by focusing on individual aspects, which are synthesized in the following study. The aim was to conduct a qualitative meta-synthesis to explore the experiences patients and their families gain during transitions in palliative care circumstances.
Methods A qualitative meta-synthesis was conducted following an inductive approach as proposed by Sandelowski and Barroso. Inclusion criteria were studies with adult persons in palliative situations and articles published in English or German. Relevant articles were identified by researching the Pubmed and Cinahl databases, as well as by hand searches in journals and reference lists for the period 2000–2015. The findings of each study were analyzed using initial coding, followed by axial and selective coding in this order. Consequently, a conceptual model was derived from the categories.
Results In total 2225 articles were identified in the literature search. Finally, 14 studies were included after the selection process. The central phenomenon observed among palliative care patients and their families was maintaining normality during transitions. Transitions are initially experienced unconsciously until a crisis occurs and responsive actions are necessary, which encourages patients and families to perceive the situation consciously and develop strategies for its negotiation. Patients remain caught between hopelessness and valuing their remaining time alive. As the illness progresses, informal caregivers reprioritize and balance their roles, and after death, family members inevitably find themselves in changed roles.
Conclusions In palliative care situations, transitions are experienced differently by patients and their families in a constant phenomenon that oscillates between unconscious and conscious perceptions of transitions. The derived conceptual model offers an additional perspective to existing models and helps to clarify the phenomenon in practical settings. The study promotes a differentiated conceptual view of transitions and emphasizes patients’ and families’ perspectives.
NachhaltigS: TC Teisnach Sensorik
Patent
Maria Kufner, F. Brand, V. Fairuschin, D. Schäffer
Abstandssensor
2018
DigitalNachhaltigExtern
Zeitschriftenartikel
Anton Schmailzl, B. Quandt, M. Schmidt, S. Hierl
In-Situ process monitoring during laser transmission welding of PA6-GF30
Procedia CIRP, vol. 74, pp. 524-527
2018
DOI: 10.1016/j.procir.2018.08.131
Quasi-simultaneous laser transmission welding is preferably used for packaging sensors and electronics. In order to protect the components from moisture, a hermetic encapsulation is needed. However, local weld seam interruptions cannot be identified with the commonly used set-path monitoring. By using a pyrometer, coaxially integrated into a 3D-scanner, gaps between the joining partners can be allocated on basis of the measured temperature. However, the scattering of the heat radiation, especially caused by the fiber reinforcement of the plastics, leads to a reduction of the accessible heat radiation, which makes the identification of gaps considerably more difficult. The herein used experimental setup is characterized by a small detection spot and only by a slight weakening of the heat radiation inside the scanner. Hence, for welding PA6-GF30, the detection of small sized gaps is possible, even if a glass fiber content of 30 percent (wt.) and a weld seam width with approximately 1 mm are given.
DigitalNachhaltigExtern
Vortrag
Simulationsgestützte Prozessentwicklung beim Laser-Durchstrahlschweißen von Thermoplasten ohne absorbierende Füllstoffe
36. CADFEM ANSYS Simulation Conference, Leipzig
2018
NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach
Patent
Christian J. Trum, Sebastian Sitzberger
Kühlsystem für eine Ultraschall-Bohrmaschine
2018
NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH Teisnach
Patent
Christian J. Trum, Sebastian Sitzberger
Kühlsystem für eine Ultraschall-Handbohrmaschine, Ultraschall-Handbohrmaschine sowie Verfahren zum Kühlen einer Schwingungserregereinheit einer Ultraschall-Handbohrmaschine
2018
GesundF: Europan 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
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.
GesundF: Europan 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
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.
GesundF: Europan 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
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.
DigitalF: Angewandte 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
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.
DigitalF: Angewandte 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
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.
DigitalF: Angewandte 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
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.
DigitalF: Angewandte 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
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.
DigitalF: Angewandte 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
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.
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