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11.
Armin Hornung Kai M. Wurm Maren Bennewitz Cyrill Stachniss Wolfram Burgard 《Autonomous Robots》2013,34(3):189-206
Three-dimensional models provide a volumetric representation of space which is important for a variety of robotic applications including flying robots and robots that are equipped with manipulators. In this paper, we present an open-source framework to generate volumetric 3D environment models. Our mapping approach is based on octrees and uses probabilistic occupancy estimation. It explicitly represents not only occupied space, but also free and unknown areas. Furthermore, we propose an octree map compression method that keeps the 3D models compact. Our framework is available as an open-source C++ library and has already been successfully applied in several robotics projects. We present a series of experimental results carried out with real robots and on publicly available real-world datasets. The results demonstrate that our approach is able to update the representation efficiently and models the data consistently while keeping the memory requirement at a minimum. 相似文献
12.
Alexander Roßnagel Gerrit Hornung Michael Knopp Daniel Wilke 《Datenschutz und Datensicherheit - DuD》2009,33(12):728-734
Trotz der wachsenden Bedeutung des Internet für die Kommunikation zwischen Bürgern, Beh?rden und Unternehmen sind die Sicherheit,
Vertraulichkeit und Rechtsverbindlichkeit des elektronischen Rechts- und Gesch?ftsverkehrs bislang nicht gew?hrleistet. Die
geplanten Bürgerportale sind ein wichtiges Instrument zur L?sung der bestehenden Probleme. 相似文献
13.
For the case of initially infinitesimally weak spherically and cylindrically imploding shocks, Ponchaut et al. (J. Fluid Mech., 560:102–122, 2006) recently obtained universal solutions. We study the effect of starting the shock with an initially finite strength on the trajectory of the shock by performing numerical calculations for the incoming shock imploding spherically into a diatomic perfect gas. Deviations from the universal solution are extremely small. A solution for the initially infinitesimally weak shock obtained by using Whitham’s (Linear and nonlinear waves, Wiley, New York, 1974) Shock Dynamics is virtually indistinguishable from the Ponchaut solution. 相似文献
14.
15.
Ricardo J. F. Branco Dr. Marianne Graber Prof. Dr. Vinciane Denis Jürgen Pleiss Prof. Dr. 《Chembiochem : a European journal of chemical biology》2009,10(18):2913-2919
Hydration is a major determinant of activity and selectivity of enzymes in organic solvents or in gas phase. The molecular mechanism of the hydration of Candida antarctica lipase B (CALB) and its dependence on the thermodynamic activity of water (aw) was studied by molecular dynamics simulations and compared to experimentally determined water sorption isotherms. Hydration occurred in two phases. At low water activity, single water molecules bound to specific water binding sites at the protein surface. As the water activity increased, water networks gradually developed. The number of protein‐bound water molecules increased linearly with aw, until at aw=0.5 a spanning water network was formed consisting of 311 water molecules, which covered the hydrophilic surface of CALB, with the exception of the hydrophobic substrate‐binding site. At higher water activity, the thickness of the hydration shell increased up to 10 Å close to aw=1. Above a limit of 1600 protein‐bound water molecules the hydration shell becomes unstable and the formation of pure water droplets occurs in these oversaturated simulation conditions. While the structure and the overall flexibility of CALB was independent of the hydration state, the flexibility of individual loops was sensitive to hydration: some loops, such as those part of the substrate‐binding site, became more flexible, while other parts of the protein became more rigid upon hydration. However, the molecular mechanism of how flexibility is related to activity and selectivity is still elusive. 相似文献
16.
Bernhard Weber Barbara Schneider Stefan Hornung Tilman Wetterling Jürgen Fritze 《Computers in human behavior》2008,24(4):1741
Negative computer attitude has been shown to be a possible co-variable in computerized examinations of psychiatric patients, affecting patient–computer interaction as well as reliability and validity of assessments.It remains still uncertain if the psychological construct of computer attitude can be dependably measured in acute psychiatric inpatients or whether it is impeded by the effects of mental illness. For that reason a German translation of the Groningen Computer Attitude Scale (GCAS) was evaluated in 160 acute psychiatric inpatients under naturalistic conditions.General test criteria (internal structure, item analysis, internal consistency, split half reliability) to a large extent corresponded to those formerly found in healthy subjects and psychiatric outpatients. The mean GCAS score was calculated as 56.2 ± 10.8 points and a significantly better computer attitude was found in male, better educated and younger patients. Some diverging correlation patterns were found in diagnostic subgroups, indicating a possible minor impact of mental disorder on computer attitude.Overall, the GCAS was found to be a suitable instrument for measuring computer attitude in acute psychiatric inpatients. It should be used in identifying patients with a negative attitude to computers in order to ensure reliability and validity of computerized assessment. 相似文献
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18.
Jager M. Osterfeld U. Ackermann H.-J. Hornung C. 《Computer Graphics and Applications, IEEE》1993,13(5):24-33
A personal-computer-based architecture that uses graphics methods to improve cooperative multimedia work over integrated services digital networks (ISDNs) is discussed. The system supports cooperative multimedia work by providing real-time video, graphics, and speech. The system requirements, components, and general architecture are considered, as is the implementation of the system 相似文献
19.
Gerrit Hornung 《Datenschutz und Datensicherheit - DuD》2007,31(3):181-185
Die Bundesregierung hat die erste Stufe der Ver?nderungen des Reisepasses — die Erg?nzung um einen RFID-Chip mit biometrischen
Gesichtsdaten — ohne Ver?nderung der passrechtlichen Grundlagen vorgenommen. Für die nunmehr in der zweiten Stufe geplante
zus?tzliche Speicherung der Fingerabdrucksdaten existiert seit Anfang 2007 ein Gesetzesentwurf, der die Vorgaben der EG-Verordnung
2252/2004 übernimmt, notwendige Folgeregelungen umsetzt und weitere Ver?nderungen des Passgesetzes enth?lt. Der Beitrag skizziert
die bisherige Entwicklung, erl?utert den Inhalt des Entwurfs und der Stellungnahme des Bundesrates und nimmt eine rechtliche
Bewertung vor. 相似文献
20.
To investigate the inductive activities of the vertebrate organizer, we transplanted the chicken organizer (Hensen's node) into zebrafish gastrula and analyzed resulting secondary axes. Grafted Hensen's node did not differentiate or participate in the secondary axis. It also did not induce a secondary notochord or expression of the genes normally expressed by the fish organizer including no tail, axial, goosecoid. Nevertheless, it recruited fish cells to organize a variety of tissues: the dorsal portion of the central nervous system including Rohon-Beard sensory neurons, otic vesicles, dorsal pigment stripe, dorsal fin, somites, heart, and pronephric ducts. Enlarged neural plate induced by the organizer was shown by the expression pattern of dlx3 and msxB genes, which demarcates the early presumptive neural tissue. In addition, Hensen's node of an earlier stage chicken embryo displayed differential movement in zebrafish from that of a later stage. This might reflect unknown differences in properties between the organizer at two different developmental stages related to its normal organizer activity. To create a model system to study the molecular mechanisms of the organizer, we next transplanted genetically modified mouse cells into zebrafish embryos. We found that Wnt3A-transfected NIH3T3 cells are much more potent in inducing a secondary axis than NIH3T3 cells alone. These results suggest that formation of a variety of tissues are controlled by signalling from the organizer itself with no requirement of participation of the organizer-derived tissues. Additionally, the activities of the organizer may involve a function of Wnt-family genes. 相似文献