@article{DasSounda2023, author = {Das, Rathindra Nath and Sounda, Sobhan Kumar}, title = {Coherence and path indistinguishability for the interference of multiple single-mode fields}, series = {Indian Journal of Physics}, volume = {97}, journal = {Indian Journal of Physics}, number = {2}, issn = {0973-1458}, doi = {10.1007/s12648-022-02398-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325146}, pages = {599-604}, year = {2023}, abstract = {A well-known result for the interference of two single-mode fields is that the degree of coherence and the degree of indistinguishability are the same when we consider the detection of a single photon. In this article, we present the relation between the degree of coherence, path indistinguishability and the fringe visibility considering interference of multiple numbers of single-mode fields while being interested in the detection of a single photon only. We will also mention how Born's rule of interference for multiple sources is reflected in these results.}, language = {en} } @article{LatoschikWienrich2022, author = {Latoschik, Marc Erich and Wienrich, Carolin}, title = {Congruence and plausibility, not presence: pivotal conditions for XR experiences and effects, a novel approach}, series = {Frontiers in Virtual Reality}, volume = {3}, journal = {Frontiers in Virtual Reality}, issn = {2673-4192}, doi = {10.3389/frvir.2022.694433}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284787}, year = {2022}, abstract = {Presence is often considered the most important quale describing the subjective feeling of being in a computer-generated and/or computer-mediated virtual environment. The identification and separation of orthogonal presence components, i.e., the place illusion and the plausibility illusion, has been an accepted theoretical model describing Virtual Reality (VR) experiences for some time. This perspective article challenges this presence-oriented VR theory. First, we argue that a place illusion cannot be the major construct to describe the much wider scope of virtual, augmented, and mixed reality (VR, AR, MR: or XR for short). Second, we argue that there is no plausibility illusion but merely plausibility, and we derive the place illusion caused by the congruent and plausible generation of spatial cues and similarly for all the current model's so-defined illusions. Finally, we propose congruence and plausibility to become the central essential conditions in a novel theoretical model describing XR experiences and effects.}, language = {en} } @article{WannagatWaizeneggerNiedling2021, author = {Wannagat, Wienke and Waizenegger, Gesine and Niedling, Gerhild}, title = {Coherence formation during narrative text processing: a comparison between auditory and audiovisual text presentation in 9- to 12-year-old children}, series = {Cognitive Processing}, volume = {22}, journal = {Cognitive Processing}, issn = {1612-4782}, doi = {10.1007/s10339-020-01008-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235744}, pages = {299-310}, year = {2021}, abstract = {In an experiment with 114 children aged 9-12 years, we compared the ability to establish local and global coherence of narrative texts between auditory and audiovisual (auditory text and pictures) presentation. The participants listened to a series of short narrative texts, in each of which a protagonist pursued a goal. Following each text, we collected the response time to a query word that was either associated with a near or a distant causal antecedent of the final sentence. Analysis of these response times indicated that audiovisual presentation has advantages over auditory presentation for accessing information relevant for establishing both local and global coherence, but there are indications that this effect may be slightly more pronounced for global coherence.}, language = {en} } @article{UllmannSauerbreyHoffmeisteretal.2019, author = {Ullmann, Tobias and Sauerbrey, Julia and Hoffmeister, Dirk and May, Simon Matthias and Baumhauer, Roland and Bubenzer, Olaf}, title = {Assessing Spatiotemporal Variations of Sentinel-1 InSAR Coherence at Different Time Scales over the Atacama Desert (Chile) between 2015 and 2018}, series = {Remote Sensing}, volume = {11}, journal = {Remote Sensing}, number = {24}, issn = {2072-4292}, doi = {10.3390/rs11242960}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193836}, pages = {2960}, year = {2019}, abstract = {This study investigates synthetic aperture radar (SAR) time series of the Sentinel-1 mission acquired over the Atacama Desert, Chile, between March 2015 and December 2018. The contribution analyzes temporal and spatial variations of Sentinel-1 interferometric SAR (InSAR) coherence and exemplarily illustrates factors that are responsible for observed signal differences. The analyses are based on long temporal baselines (365-1090 days) and temporally dense time series constructed with short temporal baselines (12-24 days). Results are compared to multispectral data of Sentinel-2, morphometric features of the digital elevation model (DEM) TanDEM-X WorldDEM™, and to a detailed governmental geographic information system (GIS) dataset of the local hydrography. Sentinel-1 datasets are suited for generating extensive, nearly seamless InSAR coherence mosaics covering the entire Atacama Desert (>450 × 1100 km) at a spatial resolution of 20 × 20 meter per pixel. Temporal baselines over several years lead only to very minor decorrelation, indicating a very high signal stability of C-Band in this region, especially in the hyperarid uplands between the Coastal Cordillera and the Central Depression. Signal decorrelation was associated with certain types of surface cover (e.g., water or aeolian deposits) or with actual surface dynamics (e.g., anthropogenic disturbance (mining) or fluvial activity and overland flow). Strong rainfall events and fluvial activity in the periods 2015 to 2016 and 2017 to 2018 caused spatial patterns with significant signal decorrelation; observed linear coherence anomalies matched the reference channel network and indicated actual episodic and sporadic discharge events. In the period 2015-2016, area-wide loss of coherence appeared as strip-like patterns of more than 80 km length that matched the prevailing wind direction. These anomalies, and others observed in that period and in the period 2017-2018, were interpreted to be caused by overland flow of high magnitude, as their spatial location matched well with documented heavy rainfall events that showed cumulative precipitation amounts of more than 20 mm.}, language = {en} } @phdthesis{Wannagat2018, author = {Wannagat, Wienke Charlotte}, title = {Cognitive Processes of Discourse Comprehension in Children and Adults - Comparisons between Written, Auditory, and Audiovisual Modes of Presentation -}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-162515}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2018}, abstract = {In drei Studien wurde untersucht, wie sich unterschiedliche Darbietungsformate (schriftlich, auditiv, audiovisuell (auditiv + Bilder) auf das Verst{\"a}ndnis semantisch identischer Inhalte auswirken. Dabei interessierte insbesondere der Entwicklungsverlauf von der ersten Klasse bis zum Erwachsenenalter. Dass sich Bilder f{\"o}rderlich auf die Verst{\"a}ndnisleistung auswirken k{\"o}nnen, gilt als gut untersucht (z.B. Carney \& Levin, 2002). Anders als viele bisherige Studien erfassen wir Textverstehen mit impliziten Maßen, die differenziertere R{\"u}ckschl{\"u}sse auf die, g{\"a}ngigen Theorien zufolge, zugrundeliegenden Prozesse zulassen: Textverstehen geht mit der Konstruktion von drei Ebenen mentaler Repr{\"a}sentationen einher (vgl. Kintsch, 1998). Weiterhin bedeutet erfolgreiches Textverstehen, eine auf lokaler und globaler Ebene koh{\"a}rente mentale Repr{\"a}sentation zu konstruieren (z.B. Schnotz \& Dutke, 2004). Mit einem Satz-Rekognitionstest (vgl. Schmalhofer \& Glavanov, 1986) untersuchten wir, ob sich das Ged{\"a}chtnis f{\"u}r die Textoberfl{\"a}che, die Textbasis und das Situationsmodell bei 103 8- und 10-J{\"a}hrigen zwischen schriftlicher, auditiver und audiovisueller (Studie 1) und bei 106 7-, 9- und 11-J{\"a}hrigen zwischen auditiver und audiovisueller Darbietung narrativer Texte (Studie 2) unterscheidet. Weiterhin (Studie 3) untersuchten wir mit 155 9- und 11-J{\"a}hrigen, inwieweit sich die F{\"a}higkeit der Inferenzbildung zur Herstellung lokaler und globaler Koh{\"a}renz zwischen schriftlicher, auditiver und audiovisueller Darbietung unterscheidet. Als Indikator dienten die Reaktionszeiten auf W{\"o}rter, die mit einem {\"u}ber (global)- oder untergeordneten (lokal) Protagonistenziel assoziiert sind. Insgesamt zeigte sich, dass Sch{\"u}ler bis zu einem Alter von 11 Jahren nicht nur die Textoberfl{\"a}che besser erinnern, sondern auch besser in der Lage sind ein Situationsmodell zu konstruieren, wenn einem Text Bilder beigef{\"u}gt sind. Dies zeigte sich sowohl im Vergleich mit auditiver als auch mit schriftlicher Darbietung. Bei Erwachsenen zeigte sich kein Effekt der Darbietungsform. Sowohl 9- als auch 11-J{\"a}hrigen gelingt außerdem die Herstellung globaler Koh{\"a}renz bei audiovisueller Darbietung besser als bei auditiver. Die schriftliche Darbietung zeigte sich im Vergleich zur auditiven sowohl im Hinblick auf lokale als auch auf globale Koh{\"a}renz {\"u}berlegen.}, subject = {Textverstehen}, language = {en} } @article{UllmannBuedelBaumhaueretal.2016, author = {Ullmann, Tobias and B{\"u}del, Christian and Baumhauer, Roland and Padashi, Majid}, title = {Sentinel-1 SAR Data Revealing Fluvial Morphodynamics in Damghan (Iran): Amplitude and Coherence Change Detection}, series = {International Journal of Earth Science and Geophysics}, volume = {2}, journal = {International Journal of Earth Science and Geophysics}, number = {1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147863}, pages = {007}, year = {2016}, abstract = {The Sentinel-1 Satellite (S-1) of ESA's Copernicus Mission delivers freely available C-Band Synthetic Aperture Radar (SAR) data that are suited for interferometric applications (InSAR). The high geometric resolution of less than fifteen meter and the large coverage offered by the Interferometric Wide Swath mode (IW) point to new perspectives on the comprehension and understanding of surface changes, the quantification and monitoring of dynamic processes, especially in arid regions. The contribution shows the application of S-1 intensities and InSAR coherences in time series analysis for the delineation of changes related to fluvial morphodynamics in Damghan, Iran. The investigations were carried out for the period from April to October 2015 and exhibit the potential of the S-1 data for the identification of surface disturbances, mass movements and fluvial channel activity in the surroundings of the Damghan Playa. The Amplitude Change Detection highlighted extensive material movement and accumulation - up to sizes of more than 4,000 m in width - in the east of the Playa via changes in intensity. Further, the Coherence Change Detection technique was capable to indicate small-scale channel activity of the drainage system that was neither recognizable in the S-1 intensity nor the multispectral Landsat-8 data. The run off caused a decorrelation of the SAR signals and a drop in coherence. Seen from a morphodynamic point of view, the results indicated a highly dynamic system and complex tempo-spatial patterns were observed that will be subject of future analysis. Additionally, the study revealed the necessity to collect independent reference data on fluvial activity in order to train and adjust the change detector.}, language = {en} } @article{MezianeMoiselloPerfettietal.2015, author = {Meziane, Hadj Boumediene and Moisello, Clara and Perfetti, Bernardo and Kvint, Svetlana and Isaias, Ioannis Ugo and Quartarone, Angelo and Di Rocco, Alessandro and Ghilardi, Maria Felice}, title = {Movement preparation and bilateral modulation of beta activity in aging and Parkinson's disease}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0114817}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-144147}, pages = {e0114817}, year = {2015}, abstract = {In previous studies of young subjects performing a reaction-time reaching task, we found that faster reaction times are associated with increased suppression of beta power over primary sensorimotor areas just before target presentation. Here we ascertain whether such beta decrease similarly occurs in normally aging subjects and also in patients with Parkinson's disease (PD), where deficits in movement execution and abnormalities of beta power are usually present. We found that in both groups, beta power decreased during the motor task in the electrodes over the two primary sensorimotor areas. However, before target presentation, beta decreases in PD were significantly smaller over the right than over the left areas, while they were symmetrical in controls. In both groups, functional connectivity between the two regions, measured with imaginary coherence, increased before the target appearance; however, in PD, it decreased immediately after, while in controls, it remained elevated throughout motor planning. As in previous studies with young subjects, the degree of beta power before target appearance correlated with reaction time. The values of coherence during motor planning, instead, correlated with movement time, peak velocity and acceleration. We conclude that planning of prompt and fast movements partially depends on coordinated beta activity of both sensorimotor areas, already at the time of target presentation. The delayed onset of beta decreases over the right region observed in PD is possibly related to a decreased functional connectivity between the two areas, and this might account for deficits in force programming, movement duration and velocity modulation.}, language = {en} } @article{HopfmannAlbertSchneideretal.2013, author = {Hopfmann, C. and Albert, F. and Schneider, C. and H{\"o}fling, S. and Kamp, M. and Forchel, A. and Kanter, I. and Reizenstein, S.}, title = {Nonlinear emission characteristics of quantum dot-micropillar lasers in the presence of polarized optical feedback}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, number = {025030}, issn = {1367-2630}, doi = {10.1088/1367-2630/15/2/025030}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123127}, year = {2013}, abstract = {We report on electrically pumped quantum dot-microlasers in the presence of polarized self-feedback. The high-\(\beta\) microlasers show two orthogonal, linearly polarized emission modes which are coupled via the common gain medium. This coupling is explained in terms of gain competition between the two lasing modes and leads to distinct differences in their input-output characteristics. By applying polarized self-feedback via an external mirror, we are able to control the laser characteristics of the emission modes in terms of the output power, the coherence time and the photon statistics. We find that linearly polarized self-feedback stabilizes the lasing of a given mode, while cross-polarized feedback between the two modes reduces strongly the intensity of the other emission mode showing particular high-intensity fluctuations and even super-thermal values of the photon autocorrelation function \(g^{(2)} (\tau)\) at zero delay. Measurements of \(g^{(2)} (\tau)\) under external feedback also allow us to detect revival peaks associated with the round trip time of the external cavity. Analyzing the damping and shape of the \(g^{(2)} (\tau)\) revival peaks by a phenomenological model provides us insight into the underlying physics such as the effective exciton lifetime and gain characteristics of the quantum dots in the active region of these microlasers.}, language = {en} }