@article{RosenbaumBlumSchweizeretal.2018, author = {Rosenbaum, David and Blum, Leonore and Schweizer, Paul and Fallgatter, Andreas J. and Herrmann, Martin J. and Ehlis, Ann-Christine and Metzger, Florian G.}, title = {Comparison of speed versus complexity effects on the hemodynamic response of the trail making test in block designs}, series = {Neurophotonics}, volume = {5}, journal = {Neurophotonics}, number = {4}, doi = {10.1117/1.NPh.5.4.045007}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226982}, pages = {045007, 1-9}, year = {2018}, abstract = {The use of functional near-infrared spectroscopy (fNIRS) in block designs provides measures of cortical activity in ecologically valid environments. However, in some cases, the use of block designs may be problematic when data are not corrected for performance in a time-restricted block. We sought to investigate the effects of task complexity and processing speed on hemodynamic responses in an fNIRS block design. To differentiate the effects of task complexity and processing speed, 20 subjects completed the trail making test (TMT) in two versions (TMT-A versus TMT-B) and three different speed levels (slow versus moderate versus fast). During TMT-A, subjects are asked to connect encircled numbers in numerically ascending order (1-2-3 ... ). In the more complex TMT-B, subjects are instructed to connect encircled numbers and letters in alternating ascending order (1-A-2-B ... ). To illustrate the obscuring effects of processing speed on task complexity, we perform two different analyses. First, we analyze the classical measures of oxygenated blood, and second, we analyze the measures corrected for the number of processed items. Our results show large effects for processing speed within the bilateral inferior frontal gyrus, left dorsolateral prefrontal cortex, and superior parietal lobule (SPL). The TMT contrast did not show significant effects with classical measures, although trends are observed for higher activation during TMT-B. When corrected for processed items, higher activity for TMT-B in comparison to TMT-A is found within the SPL. The results are discussed in light of recent research designs, and simple to use correction methods are suggested. (c) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.}, language = {en} } @phdthesis{Metzger2004, author = {Metzger, Florian}, title = {Bedeutung von Elektrodenzahl und anderer Parameter bei dreidimensionaler Quellenlokalisation (LORETA) in ereigniskorrelierten Potenzialen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-13949}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {Ausf{\"u}hrung und Verhinderung einer motorischen Antwort sind Vorg{\"a}nge, die sich in der Lokalisation von aktivierten Arealen im Gehirn deutlich voneinander unterscheiden. Zu deren Untersuchung kann die Inhibition und Exekution von motorischen Antworten durch Tests wie den Continuous Performance Test (Go-Nogo-Paradigma) ausgel{\"o}st werden. Um f{\"u}r die Identifikation unterschiedlicher aktivierter Areale im Gehirn die hohe zeitliche Aufl{\"o}sung EEG-basierter Daten nutzen zu k{\"o}nnen, ben{\"o}tigt man ein Verfahren zur dreidimensionalen Quellenlokalisation. Das Problem der eindeutigen lokalen Zuordnung von aktivierten Quellen im EEG wird durch N{\"a}herungsberechnungen wie LORETA (Low resolution electromagnetic tomography) zu l{\"o}sen versucht. F{\"u}r die Anwendung von LORETA existiert bisher kein Standard hinsichtlich Elektrodenzahl und Mittelung von Elektroden (Regularisierung). Dadurch entstanden die Leitfragen der Untersuchung nach Ver{\"a}nderung der Ergebnisse durch unterschiedliche Elektrodenanzahl oder Verwendung der Regularisierung. Zus{\"a}tzlich wurde der Einfluss der Berechnung des Global Field Power - Peaks betrachtet, anhand dessen der genaue Zeitpunkt der Bildberechnung bestimmt wird. Die aus diesen systematisch variierten Parametern resultierenden Ergebnisse wurden mit den Ergebnissen der bisherigen EEG- und fMRI-Studien verglichen.}, language = {de} } @techreport{MetzgerSchroederRafetseder2021, type = {Working Paper}, author = {Metzger, Florian and Schr{\"o}der, Svenja and Rafetseder, Albert}, title = {Subjective And Objective Assessment Of Video Game Context Factors}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-242471}, pages = {7}, year = {2021}, abstract = {The recently published ITU-T Recommendation G1.032 proposes a list of factors that may influence cloud and online gaming Quality of Experience (QoE). This paper provides two practical evaluations of proposed system and context influence factors: First, it investigates through an online survey (n=488) the popularity of platforms, preferred ways of distribution, and motivational aspects including subjective valuations of characteristics offered by today's prevalent gaming platforms. Second, the paper evaluates a large dataset of objective metrics for various gaming platforms: game lists, playthrough lengths, prices, etc., and contrasts these metrics against the gamers' opinions. The combined data-driven approach presented in this paper complements in-person and lab studies usually employed.}, subject = {Videospiel}, language = {en} } @techreport{MetzgerRafetsederSchroederetal.2016, type = {Working Paper}, author = {Metzger, Florian and Rafetseder, Albert and Schr{\"o}der, Svenja and Zwickl, Patrick}, title = {The Prospects of Cloud Gaming: Do the Benefits Outweigh the Costs?}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-242452}, pages = {10}, year = {2016}, abstract = {In recent years, cloud gaming has become a popular research topic and has claimed many benefits in the commercial domain over conventional gaming. While, cloud gaming platforms have frequently failed in the past, they have received a new impetus over the last years that brought it to the edge of commercial breakthrough. The fragility of the cloud gaming market may be caused by the high investment costs, offered pricing models or competition from existing "{\`a} la carte" platforms. This paper aims at investigating the costs and benefits of both platform types through a twofold approach. We first take on the perspective of the customers, and investigate several cloud gaming platforms and their pricing models in comparison to the costs of other gaming platforms. Then, we explore engagement metrics in order to assess the enjoyment of playing the offered games. Lastly, coming from the perspective of the service providers, we aim to identify challenges in cost-effectively operating a large-scale cloud gaming service while maintaining high QoE values. Our analysis provides initial, yet still comprehensive reasons and models for the prospects of cloud gaming in a highly competitive market.}, subject = {Cloud Computing}, language = {en} } @techreport{GrigorjewMetzgerHossfeldetal.2020, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and G{\"o}tz, Franz-Josef and Schmitt, J{\"u}rgen and Chen, Feng}, title = {Technical Report on Bridge-Local Guaranteed Latency with Strict Priority Scheduling}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-198310}, year = {2020}, abstract = {Bridge-local latency computation is often regarded with caution, as historic efforts with the Credit-Based Shaper (CBS) showed that CBS requires network wide information for tight bounds. Recently, new shaping mechanisms and timed gates were applied to achieve such guarantees nonetheless, but they require support for these new mechanisms in the forwarding devices. This document presents a per-hop latency bound for individual streams in a class-based network that applies the IEEE 802.1Q strict priority transmission selection algorithm. It is based on self-pacing talkers and uses the accumulated latency fields during the reservation process to provide upper bounds with bridge-local information. The presented delay bound is proven mathematically and then evaluated with respect to its accuracy. It indicates the required information that must be provided for admission control, e.g., implemented by a resource reservation protocol such as IEEE 802.1Qdd. Further, it hints at potential improvements regarding new mechanisms and higher accuracy given more information.}, subject = {Echtzeit}, language = {en} } @techreport{GrigorjewMetzgerHossfeldetal.2020, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and G{\"o}tz, Franz-Josef and Chen, Feng and Schmitt, J{\"u}rgen}, title = {Asynchronous Traffic Shaping with Jitter Control}, doi = {10.25972/OPUS-20582}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-205824}, pages = {8}, year = {2020}, abstract = {Asynchronous Traffic Shaping enabled bounded latency with low complexity for time sensitive networking without the need for time synchronization. However, its main focus is the guaranteed maximum delay. Jitter-sensitive applications may still be forced towards synchronization. This work proposes traffic damping to reduce end-to-end delay jitter. It discusses its application and shows that both the prerequisites and the guaranteed delay of traffic damping and ATS are very similar. Finally, it presents a brief evaluation of delay jitter in an example topology by means of a simulation and worst case estimation.}, subject = {Echtzeit}, language = {en} } @article{BurnsGoldsteinNewgreenetal.2016, author = {Burns, Alan J. and Goldstein, Allan M. and Newgreen, Donald F. and Stamp, Lincon and Sch{\"a}fer, Karl-Herbert and Metzger, Marco and Hotta, Ryo and Young, Heather M. and Andrews, Peter W. and Thapar, Nikhil and Belkind-Gerson, Jaime and Bondurand, Nadege and Bornstein, Joel C. and Chan, Wood Yee and Cheah, Kathryn and Gershon, Michael D. and Heuckeroth, Robert O. and Hofstra, Robert M.W. and Just, Lothar and Kapur, Raj P. and King, Sebastian K. and McCann, Conor J. and Nagy, Nandor and Ngan, Elly and Obermayr, Florian and Pachnis, Vassilis and Pasricha, Pankaj J. and Sham, Mai Har and Tam, Paul and Vanden Berghe, Pieter}, title = {White paper on guidelines concerning enteric nervous system stem cell therapy for enteric neuropathies}, series = {Developmental Biology}, volume = {417}, journal = {Developmental Biology}, number = {2}, doi = {10.1016/j.ydbio.2016.04.001}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187415}, pages = {229-251}, year = {2016}, abstract = {Over the last 20 years, there has been increasing focus on the development of novel stem cell based therapies for the treatment of disorders and diseases affecting the enteric nervous system (ENS) of the gastrointestinal tract (so-called enteric neuropathies). Here, the idea is that ENS progenitor/stem cells could be transplanted into the gut wall to replace the damaged or absent neurons and glia of the ENS. This White Paper sets out experts' views on the commonly used methods and approaches to identify, isolate, purify, expand and optimize ENS stem cells, transplant them into the bowel, and assess transplant success, including restoration of gut function. We also highlight obstacles that must be overcome in order to progress from successful preclinical studies in animal models to ENS stem cell therapies in the clinic.}, language = {en} } @techreport{Metzger2020, type = {Working Paper}, author = {Metzger, Florian}, title = {Crowdsensed QoE for the community - a concept to make QoE assessment accessible}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203748}, pages = {7}, year = {2020}, abstract = {In recent years several community testbeds as well as participatory sensing platforms have successfully established themselves to provide open data to everyone interested. Each of them with a specific goal in mind, ranging from collecting radio coverage data up to environmental and radiation data. Such data can be used by the community in their decision making, whether to subscribe to a specific mobile phone service that provides good coverage in an area or in finding a sunny and warm region for the summer holidays. However, the existing platforms are usually limiting themselves to directly measurable network QoS. If such a crowdsourced data set provides more in-depth derived measures, this would enable an even better decision making. A community-driven crowdsensing platform that derives spatial application-layer user experience from resource-friendly bandwidth estimates would be such a case, video streaming services come to mind as a prime example. In this paper we present a concept for such a system based on an initial prototype that eases the collection of data necessary to determine mobile-specific QoE at large scale. In addition we reason why the simple quality metric proposed here can hold its own.}, subject = {Quality of Experience}, language = {en} } @article{Trujillo‐VieraEl‐MerahbiSchmidtetal.2021, author = {Trujillo-Viera, Jonathan and El-Merahbi, Rabih and Schmidt, Vanessa and Karwen, Till and Loza-Valdes, Angel and Strohmeyer, Akim and Reuter, Saskia and Noh, Minhee and Wit, Magdalena and Hawro, Izabela and Mocek, Sabine and Fey, Christina and Mayer, Alexander E. and L{\"o}ffler, Mona C. and Wilhelmi, Ilka and Metzger, Marco and Ishikawa, Eri and Yamasaki, Sho and Rau, Monika and Geier, Andreas and Hankir, Mohammed and Seyfried, Florian and Klingenspor, Martin and Sumara, Grzegorz}, title = {Protein Kinase D2 drives chylomicron-mediated lipid transport in the intestine and promotes obesity}, series = {EMBO Molecular Medicine}, volume = {13}, journal = {EMBO Molecular Medicine}, number = {5}, doi = {10.15252/emmm.202013548}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-239018}, year = {2021}, abstract = {Lipids are the most energy-dense components of the diet, and their overconsumption promotes obesity and diabetes. Dietary fat content has been linked to the lipid processing activity by the intestine and its overall capacity to absorb triglycerides (TG). However, the signaling cascades driving intestinal lipid absorption in response to elevated dietary fat are largely unknown. Here, we describe an unexpected role of the protein kinase D2 (PKD2) in lipid homeostasis. We demonstrate that PKD2 activity promotes chylomicron-mediated TG transfer in enterocytes. PKD2 increases chylomicron size to enhance the TG secretion on the basolateral side of the mouse and human enterocytes, which is associated with decreased abundance of APOA4. PKD2 activation in intestine also correlates positively with circulating TG in obese human patients. Importantly, deletion, inactivation, or inhibition of PKD2 ameliorates high-fat diet-induced obesity and diabetes and improves gut microbiota profile in mice. Taken together, our findings suggest that PKD2 represents a key signaling node promoting dietary fat absorption and may serve as an attractive target for the treatment of obesity.}, language = {en} }