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The cross-sensitivity of chemical sensors for several metal ions resembles in a way the overlapping sensitivity of some biological sensors, like the optical colour receptors of human retinal cone cells. While it is difficult to assign crisp classification values to measurands based on complex overlapping sensory signals, fuzzy logic offers a possibility to mathematically model such systems. Current work goes into the direction of mixed heavy metal solutions and the combination of fuzzy logic with heavy metal-sensitive, silicon-based chemical sensors for training scenarios of arbitrary sensor/probe combinations in terms of an electronic tongue. Heavy metals play an important role in environmental analysis. As trace elements as well as water impurities released from industrial processes they occur in the environment. In this work, the development of a new fuzzy logic method based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The critical validation of the developed fuzzy logic program will be demonstrated by means of measurements in unknown single- and multi-component heavy metal solutions. Limitations of this program and a comparison between calculated and expected values in terms of analyte composition and heavy metal ion concentration will be shown and discussed.
The Virtual Memory Palace
(2006)
The intention of the Virtual Memory Palace is to help people memorize information by addressing their visual memory. The concept is based on the “Memory Palace” as an ancient Greek memorization technique, where symbols are placed in a certain way within an imaginative building in order to remember the original information whenever the mind goes through the vision of this building again. The goal of this work was to create such a Memory Palace in a virtual environment, so it requires less creative effort of the contemporary learner than was necessary in ancient Greece. The Virtual Memory Palace offers the possibility to freely explore a virtual 3d architectural model and to place icons at various locations within this model. Specific behaviors were assigned to these locations to make them more memorable. To test the benefit of this concept, an experiment with 15 subjects was conducted. The results show a higher remembrance rate of items learned in the Virtual Memory Palace compared to a wordlist. The observations made during the test showed that most of the subjects enjoyed the memorization environment and were astonished how well the Virtual Memory Palace worked for them.
The work being described in this paper is the result of a cooperation project between the Institute of Visual Computing at the Bonn-Rhein-Sieg University of Applied Sciences, Germany and the Laboratory of Biomedical Engineering at the Federal University of Uberlândia, Brazil. The aim of the project is the development of a virtual environment based training simulator which enables for better and faster learning the control of upper limb prostheses. The focus of the paper is the description of the technical setup since learning tutorials still need to be developed as well as a comprehensive evaluation still needs to be carried out.
Fast generation of molecular surfaces from 3D data fields with an enhanced "marching cube" algorithm
(1993)
An improved version of the "marching cubes" algorithm [W. Lorensen and H. Cline, Comp. Graph. 21, (1987)] for the generation of isosurfaces from 3D data fields is presented and applied to molecular surfaces. The new algorithm avoids inconsistent pattern definitions of the original one, which lead to artificial gaps. The advantage of a logarithmic interpolation procedure, in particular for data fields typically occurring in molecular science, is demonstrated. An example is the generation of molecular surfaces based upon electron density data.
Virtuelle Umgebungen
(2000)
Augmented Perception - AuPer
(2004)
The objective of the FIVIS project is to develop a bicycle simulator which is able to simulate real life bicycle ride situations as a virtual scenario within an immersive environment. A sample test bicycle is mounted on a motion platform to enable a close to reality simulation of turns and balance situations. The visual field of the bike rider is enveloped within a multi-screen visualization environment which provides visual data relative to the motion and activity of the test bicycle. This implies the bike rider has to pedal and steer the bicycle as they would a traditional bicycle, while forward motion is recorded and processed to control the visualization. Furthermore, the platform is fed with real forces and accelerations that have been logged by a mobile data acquisition system during real bicycle test drives. Thus, using a feedback system makes the movements of the platform reflect the virtual environment and the reaction of the driver (e.g. steering angle, step rate).
Die Visualisierung und Quantifizierung von Datenfeldern im dreidimensionalen Raum gewinnt in vielen Bereichen von Wissenschaft und Technik mehr und mehr an Bedeutung. Anschauliche Visualisierung der Daten stellt eine Voraussetzung für effektive Kommunikation zwischen Mensch und Maschine dar. Dies läßt sich mit Hilfe der Computergraphik durch die Darstellung von Isoflächen, die einen bestimmten Datenwert repräsentieren, erreichen. Für die Visualisierung zeitabhängiger Resultate (z.B. dynamische Simulationen) sowie zur hochgradig interaktiven Bearbeitung der Daten sind extrem schnelle Computerprogramme zur Generierung dieser Isooberflächen erforderlich. Ein Beispiel für einen derartigen Algorithmus ist die hier vorgestellte Triangulation dreidimensionaler Gitter auf der Basis einzelner Würfel als Gitterelemente.
An algorithm for the generation of a solid molecular surface from a given number of surface points in 3D space is presented. This surface is represented by a triangle mesh. Such a mesh of triangles is not uniquely defined by the position vectors of the surface points, and there is no straight forward algorithm for triangulation. In this paper a hierarchy of algorithms is described which successfully works for the automatic triangulation of molecular surfaces of all sizes. Some examples are given for the application of this solid surface approach in molecular modelling of proteins.
The objective of the presented approach is to develop a 3D-reconstruction method for micro organisms from sequences of microscopic images by varying the level-of-focus. The approach is limited to translucent silicatebased marine and freshwater organisms (e.g. radiolarians). The proposed 3D-reconstruction method exploits the connectivity of similarly oriented and spatially adjacent edge elements in consecutive image layers. This yields a 3D-mesh representing the global shape of the objects together with details of the inner structure. Possible applications can be found in comparative morphology or hydrobiology, where e.g. deficiencies in growth and structure during incubation in toxic water or gravity effects on metabolism have to be determined.
In this work, the development of a fuzzy logic method for the analysis of chemical sensor data based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The approach is based on the concept of linguistic variables, combining data from a sensor array to gain quantitative as well as qualitative information on heavy metal ions in unknown single- and multi-component heavy metal solutions. Current and general limitations of this approach will be shown and discussed based on a comparison between calculated and expected values.
New strategies for the use of interactive computer graphics for man-machine communication in the field of molecular modelling are described. It is shown that in particular the concept of molecular surfaces is very helpful for the discussion of specific intermolecular interactions: attractive and repulsive forces towards an interaction partner can be mapped by color coding on the molecular surface.
Benches and CAVEs
(1997)
