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Automatic System (automatic + system)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Reconstructing head models from photographs for individualized 3D-audio processing

COMPUTER GRAPHICS FORUM, Issue 7 2008
M. Dellepiane
Abstract Visual fidelity and interactivity are the main goals in Computer Graphics research, but recently also audio is assuming an important role. Binaural rendering can provide extremely pleasing and realistic three-dimensional sound, but to achieve best results it's necessary either to measure or to estimate individual Head Related Transfer Function (HRTF). This function is strictly related to the peculiar features of ears and face of the listener. Recent sound scattering simulation techniques can calculate HRTF starting from an accurate 3D model of a human head. Hence, the use of binaural rendering on large scale (i.e. video games, entertainment) could depend on the possibility to produce a sufficiently accurate 3D model of a human head, starting from the smallest possible input. In this paper we present a completely automatic system, which produces a 3D model of a head starting from simple input data (five photos and some key-points indicated by user). The geometry is generated by extracting information from images and accordingly deforming a 3D dummy to reproduce user head features. The system proves to be fast, automatic, robust and reliable: geometric validation and preliminary assessments show that it can be accurate enough for HRTF calculation. [source]

Automatic Palletizing of Concrete Pavement Blocks: An Algorithm for Near-Optimal Assembly

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 3 2001
Shraga Shoval
Palletizing concrete pavement blocks is a labor-intensive task that requires high levels of workmanship, skill, and concentration. This article proposes an automatic system in which palettes with required design patterns are assembled automatically off-site and then shipped to the construction site. The efficiency of the assembly process can be improved by incorporating automatic equipment consisting of assembly heads and feeders. An algorithm was developed to determine the optimal layout of the feeders (of different blocks) around the palette and the exact assembly sequence of each layer of blocks. Experimental results show that the algorithm is near optimal and that the solutions provided by it reduce palletizing cycle time for various patterns and sizes of concrete block by 20 to 30 percent. [source]

Automatic analysis of aqueous specimens for phytoplankton structure recognition and population estimation

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 9 2006
Karsten Rodenacker
Abstract An automatic microscope image acquisition, evaluation, and recognition system was developed for the analysis of Utermöhl plankton chambers in terms of taxonomic algae recognition. The system called PLASA (Plankton Structure Analysis) comprises (1) fully automatic archiving (optical fixation) of aqueous specimens as digital bright field and fluorescence images, (2) phytoplankton analysis and recognition, and (3) training facilities for new taxa. It enables characterization of aqueous specimens by their populations. The system is described in detail with emphasis on image analytical aspects. Plankton chambers are scanned by sizable grids, divers objective(s), and up to four fluorescence spectral bands. Acquisition positions are focused and digitized by a TV camera and archived on disk. The image data sets are evaluated by a large set of quantitative features. Automatic classifications for a number of organisms are developed and embedded in the program. Interactive programs for the design of training sets were additionally implemented. A long-term sampling period of 23 weeks from two ponds at two different locations each was performed to generate a reliable data set for training and testing purposes. These data were used to present this system's results for phytoplankton structure characterization. PLASA represents an automatic system, comprising all steps from specimen processing to algae identification up to species level and quantification. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source]

Expected loss-based alarm threshold set for earthquake early warning systems

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 9 2007
Iunio Iervolino
Abstract Earthquake early warning systems (EEWS) seem to have potential as tools for real-time seismic risk management and mitigation. In fact, although the evacuation of buildings requires warning time not available in many urbanized areas threatened by seismic hazard, they may still be used for the real-time protection of critical facilities using automatic systems in order to reduce the losses subsequent to a catastrophic event. This is possible due to the real-time seismology, which consists of methods and procedures for the rapid estimation of earthquake features, as magnitude and location, based on measurements made on the first seconds of the P -waves. An earthquake engineering application of earthquake early warning (EEW) may be intended as a system able to issue the alarm, if some recorded parameter exceeds a given threshold, to activate risk mitigation actions before the quake strikes at a site of interest. Feasibility analysis and design of such EEWS require the assessment of the expected loss reduction due to the security action and set of the alarm threshold. In this paper a procedure to carry out these tasks in the performance-based earthquake engineering probabilistic framework is proposed. A merely illustrative example refers to a simple structure assumed to be a classroom. Structural damage and non-structural collapses are considered; the security action is to shelter occupants below the desks. The cost due to a false alarm is assumed to be related to the interruption of didactic activities. Results show how the comparison of the expected losses, for the alarm-issuance and non-issuance cases, allows setting the alarm threshold on a quantitative and consistent basis, and how it may be a tool for the design of engineering applications of EEW. Copyright © 2007 John Wiley & Sons, Ltd. [source]