15,684 research outputs found
Evaluation of binocular eye trackers and algorithms for 3D gaze interaction in virtual reality environments
No full textPfeiffer T, Latoschik ME, Wachsmuth I. Evaluation of binocular eye trackers and algorithms for 3D gaze interaction in virtual reality environments. JVRB - Journal of Virtual Reality and Broadcasting. 2008;5(16):1660.Tracking user's visual attention is a fundamental aspect in novel human-computer interaction paradigms found in Virtual Reality. For example, multimodal interfaces or dialogue-based communications with virtual and real agents greatly benefit from the analysis of the user's visual attention as a vital source for deictic references or turn-taking signals. Current approaches to determine visual attention rely primarily on monocular eye trackers. Hence they are restricted to the interpretation of two-dimensional fixations relative to a defined area of projection. The study presented in this article compares precision, accuracy and application performance of two binocular eye tracking devices. Two algorithms are compared which derive depth information as required for visual attention-based 3D interfaces. This information is further applied to an improved VR selection task in which a binocular eye tracker and an adaptive neural network algorithm is used during the disambiguation of partly occluded objects
MABS validation through repeated execution and data mining analysis
No full textAgent Based Modelling is the most interesting and advanced approach for simulating a complex system: in a social context, the single parts and the whole are often very hard to describe in detail. Besides, there are agent based formalisms which allow to study the emergency of social behaviour with the creation and study of models, known as artificial societies. Thanks to the ever increasing computational power, it's been possible to use such models to create software, based on intelligent agents, which aggregate behaviour is complex and difficult to predict, and can be used in open and distributed systems. Data mining is born in the last decades in order to help users in finding useful knowledge from the otherwise overwhelming amount of data available nowadays from the web and the data collected every day by companies. Data Mining techniques can therefore be the keystone to reveal non-trivial knowledge expressed by the initial assumption used to build the micro-level of the model and the structure of the society of agents that emerged from the simulation
Benefits of locating overt visual attention in space using binocular eye tracking for mixed reality applications
No full textPfeiffer T, Mattar N. Benefits of locating overt visual attention in space using binocular eye tracking for mixed reality applications. In: Workshop-Proceedings der Tagung Mensch & Computer 2009: Grenzenlos frei!?. Berlin: Logos Berlin; 2009.The "Where?" is quite important for Mixed Reality applications: Where is the user looking at? Where should augmentations be displayed? The location of the overt visual attention of the user can be used both to disambiguate referent objects and to inform an intelligent view management of the user interface. While the vertical and horizontal orientation of attention is quite commonly used, e.g. derived from the orientation of the head, only knowledge about the distance allows for an intrinsic measurement of the location of the attention. This contribution reviews our latest results on detecting the location of attention in 3D space using binocular eye tracking
Data for: Chronology, stratigraphy and hydrological modelling of extensive wetlands and paleolakes in the hyperarid core of the Atacama Desert during the late Quaternary
No full textRadiocarbon Database for the Pampa del Tamarugal wetlands and paleolakes (Appendix A) Radiocarbon Database for the Antofagasta Region Central Depression wetlands and paleolakes (Appendix B
Risk factors for paravalvular leak after transcatheter aortic valve replacement
No full textObjective. To assess risk factors for paravalvular leak (PVL) after transcatheter aortic valve implantation (TAVI) in a large single-center cohort, including measurement of aortic valve calcification using a reproducible method.
Methods. We retrospectively analyzed preoperative contrast-enhanced multidetector computed tomography (MDCT) scans of patients who underwent TAVI in our center between 2009 and 2016. Calcium volume was calculated for each aortic cusp in the aortic valve (AV), left ventricular outflow tract (LVOT) and device-landing zone (DLZ).
Results. Overall, 539 patients were included in the study (Edwards SapienXT, n=192; Edwards Sapien3, n=206; Medtronic CoreValve EvolutR, n=44; Symetis Acurate, n=97). Median calcium volume in the DLZ was 757 mm3, with no significant differences among the four prosthesis groups. None of the patients had severe PVL. The overall incidence of mild-to-moderate PVL was 15.8% (95% CI: 12.8-19.1%). On multivariate logistic regression, DLZ calcification (p=0.00006; OR for an increase of 100 mm3 1.08; 95% CI: 1.04-1.13) and use of the CoreValve (p=0.0028; OR 4.1; 95% CI: 1.6-10 with SapienXT as reference) prosthesis were found to be associated with ≥mild PVL. In contrast, degree of oversizing (p=0.002; OR 0.97; 95% CI: 0.95-0.99), and use of Sapien3 (p=0.00005; OR 0.23; 95% CI: 0.11-0.47 with SapienXT as reference) were associated with a lower incidence of ≥mild PVL.
Conclusions. Aortic calcification volume in the DLZ is associated with residual PVL after TAVI. When taking calcification into account, the balloon-expandable prosthesis Sapien3 seems to be associated with a lower incidence of PVL
CHLSOC: The Chilean Soil Organic Carbon database
No full textSoil Organic Carbon dataset from Chile which is fully described in the article "CHLSOC: The Chilean Soil Organic Carbon database, amulti-institutional collaborative effort" by Pfeiffer et al
Facades of the Libreria di San Marco in Venice, The: An Interpretation of the Design Process
No full text"A new work in which I propose an interpretation of the design process Sansovino used to create the magnificent facades of the Libreria di San Marco in Venice, a masterpiece of Renaissance architecture." Sent to Marquand librarian by author Dec. 202
Art without an Author: Vasari’s Lives and Michelangelo’s Death
No full textMonografia sulla rappresentazione di Michelangelo nelle due edizioni delle Vite, sulla storia del libro e la questione della sua paternitàBook dedicated to the representation of Michelangelo in Vasari's Lives of the Artists, to the history of the book, and to the problem of its authorshi
Unio elongatulus C. Pfeiffer 1825
No full textUnio elongatulus — Neotype Description: Shell elongate, more than twice the height, with anterior portion less than 1/4 of posterior one, rather thickened and moderately compressed. Dorsal and ventral margins almost parallel, anterior dorsal margin curved, dorsal margin straight, a little angled at the junction with posterior margin; posterior end tapered. Umbos swollen, with irregular and tubercular rugae. Ligament narrow in dorsal view. External surface dark brown in colour, with well visible growth lines. Hinge plate straight; cardinal teeth thick and flat; posterior-lateral teeth straight and very long (1/3 of shell length). Anterior adductor scar near shell margin, posterior adductor scar at the end of posteriorlateral tooth. Internal surface white and shiny, nacreous, brown along the margin. Shell length: 97.6 mm; shell height: 43.1 mm; breadth of both valves closed: 28.4 mm (Fig. 6A). The population from the Vipava River is a little variable in shape and colour, with some shorter specimens, ventral margin also slightly sinuous and brownyellowish colour (Fig. 6 B–E). Genetics: The specimen is genetically determined by its sequence of a fragment of the mtDNA gene cytochrome c oxidase subunit I (COI) (GenBank Accession Number: MG967432). This way the criteria of Article number 75.3 of the ICZN Code are satisfied and the neotype of Unio elongatulus is hereby formally established. Ecology and distribution: This species, as other congenerics, lives mostly in rivers, channels and lakes. Its distribution, according to our genetic data, covers all main tributaries of the Adriatic, from the Ofanto River in Southern Italy to the Po River and other North Adriatic basins in Italy, to Croatian and Albanian hydrographical basins flowing into the Adriatic Sea. Collection: The neotype is stored in the malacological collection of the Natural History Museum of the University of Florence, “La Specola” Zoology section (MZUF BC/53148)Published as part of Marrone, Federico, Nardi, Gianbattista, Cianfanelli, Simone, Govedič, Marijan, Barra, Salvatore Alessandro, Arculeo, Marco & Bodon, Marco, 2019, Diversity and taxonomy of the genus Unio Philipsson in Italy, with the designation of a neotype for Unio elongatulus C. Pfeiffer (Mollusca, Bivalvia, Unionidae), pp. 339-374 in Zootaxa 4545 (3) on page 356, DOI: 10.11646/zootaxa.4545.3.2, http://zenodo.org/record/261891
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