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Simultaneous detection of cyanide and heavy metals for environmental analysis by means of µISEs
(2010)
In environmental analysis, cyanide and heavy metals play an important role, because these substances are highly toxic for biological systems. They can lead to chronic and acute diseases. Due to the chemical properties of cyanide it is frequently used for industrial processes such as extraction of silver and gold. Heavy metals can be found as trace elements in nature and are often applied in industries e.g., galvanization processes. Up to now, cyanide and heavy metals can be detected by several sensors separately and their detection is often limited to laboratory investigations. In this publication, with regard to an in situ analysis, a new miniaturized silicon.-based sensor system for the simultaneous detection of cyanide and heavy metals in aqueous solutions is presented that is based on chalcogenide glass-based microion-selective electrodes (µISEs). The µISEs are incorporated into a specially designed measuring system for the simultaneous detection of heavy metals and cyanide in solutions and validated by simultaneous measurements of Cu(2+)- and CN(-)-ions, Cd(2+)- and CN(-)- ions and Pb(2+)- and CN(-)-ions. The particular sensor system has shown good sensor properties in the mu-molar ion-concentration range. For simultaneous measurements in complex heavy metal and cyanide solutions an intelligent software using fuzzy logic is discussed.
In this paper, we describe an approach to use storytelling in academic teaching as a means for background research to hypermedia and virtual reality topics in computer science. Interactivity within this context means selective authoring rather than immersive interaction. In contrast to existing approaches a Hypermedia Novel environment allows an iterative approach to the narrative content, thereby integrating story authoring and story reception at any time. The narrative practice and background research as well as the resulting product can supplement lecture material with comparable success to traditional academic teaching approaches. In addition there is the added value of soft skill training and a gain of expert knowledge in areas of personal background research.
Game technology has been widely used for educational applications, however, despite the common use of background music in games, its effect on learning has been largely unexplored. This paper discusses how music played in the background of a computer-animated history lesson affected participants’ memory for facts. A virtual history lesson was presented to participants with different background stimuli (music or no-music) to test the effect of music on memory. To test the role of immersion on memory and its possible relationship to the music, two different display systems (3-monitor display system or immersive Reality Center) were used in the study. Overall, participants remembered a significantly higher number of facts using the 3-monitor display system, particularly if no background music was played in the second half of the history lesson. Conversely, for participants using the Reality Center, significantly higher recall of facts was found when participants listened to music in the second half of the history lesson. Cognitive load/overload and (un-)familiarity with the technology are offered as explanations.
The action of a series of tetraphenylborate ion (TPB) derivatives on yeast cells was studied by electro-rotation of the pre-treated cells. TPB derivatives in which all four phenyl groups were substituted with fluorine, chlorine or trifluoromethyl were much more toxic than the unsubstituted compound, the effect increasing dramatically with increasing size of substituents. These observations suggest that the toxicity of these hydrophobic ions is determined mainly by their size and possibly also by the chemical inductivity of their substituent groups. The order of the toxicities of these ions was in fair agreement with literature values for their translocation rates across artificial bilayers. Incubation times of 3 h were used as standard, longer incubations (up to 48 h) showed that the number of cells affected by low doses of TPB increased with the logarithm of time after the first hour of incubation. Although measurements of the percentage of cells showing co-field rotation showed that controls were not adversely affected by incubations as long as 9 h, rotation spectra showed that some cells suffer loss of internal conductivity during extended incubations. Decrease of the pH of the incubation medium, or inclusion of high concentrations of NaCl or KCl, potentiated the effects of these hydrophobic ions. The toxicity developed slowly, and the sensitivity of the assay was only very weakly dependent on the cell suspension density.
The Atmosphaeres project aims to reduce sufferers’ stress and pain levels by using 360° video environments that are presented in a highly immersive Head-Mounted Display (HMD). Here we report first insights of our prototype combination of the 360° video environments and the Oculus Rift, the HMD used for our project. We find that our ‘Atmosphaeres’ are capable of truly transporting the user to another, virtually created location, however, there were a number of restrictions with the first system, including image quality and nausea which we hope to eliminate with the system we present in this paper. There are also a number of research questions that need to be considered for the use of the Atmosphaeres in stress and pain management or for general relaxation purposes. These questions include whether 360° video environments are capable of reducing stress and experienced pain and whether changes to the Oculus Rift DK2 do in fact reduce the nausea that was often caused by the DK1. Sound is another important yet often under-considered factor in many Virtual Reality applications and questions we seek to answer revolve around how the quality and type of audio contribute to users’ feeling of presence and ultimately their stress and pain levels.
In this paper, we present a stereo-vision based approach for road sign detection. As opposed to traffic signs, which are typically made up of well-defined pictographs, road signs can contain arbitrary information. Here, color and shape are the main two cues that represent different classes of road signs, e.g. signs on the highway vs. signs on country roads. To that extent, the proposed model couples efficient low-level color-based segmentation in HSL space with higher-level constraints that integrate prior knowledge on sign geometry in 3D through stereo-vision. Additional robustness is obtained by temporal integration as well as by matching detected signs against the results of object detectors for other traffic participants. The effectiveness of our approach is demonstrated on a real-world stereo-vision dataset (3700 images) that has been captured from a moving vehicle on German highways and country roads. Our results indicate competitive performance at real-time speeds.
ATM virtual studio services
(1996)
The term "virtual studio" refers to real-time 3D graphics systems used to render a virtual set in sync with live camera motion. As the camera pans and zooms, the virtual set is redrawn from the correct perspective. Using blue room techniques, actors in front of the real camera are then “placed in” the virtual set. Current virtual studio systems are centralized – the blue room, cameras, renderers etc. are located at a single site. However distributed configurations offer significant economies such as the sharing of expensive rendering equipment among many sites. This paper describes early expe- riences of the DVP1 project in the realization of a distributed virtual studio. In particular we de- scribe the first video production using a distributed virtual studio over ATM and make observations concerning network QOS requirements.
A triangulation algorithm for a dotted surface (i.e. a surface defined by point coordinates in three dimensions) is given. The individual triangles are generated on the basis of a hierarchy of strategies according to increasing surface complexity. While for small molecules an elementary algorithm is sufficient to triangulate the surface, large molecules-like proteins-generally need all steps of the hierarchy. Although this program has been developed with the aim of triangulating molecular surfaces, it can in principle be applied to any surface defined by 3D point coordinates.
A new method for display and analysis of lipophilic/hydrophilic properties on molecular surfaces is presented. The present approach is based on the concept of Crippen and coworkers that the overall hydrophobicity of a molecule (measured as the logarithm of the partition coefficient in an octanol/water system) can be obtained as a superposition of single atom contributions. It is also based on the concept of molecular lipophilicity potentials (MLP) first introduced by Audry and coworkers in order to establish a 3D lipophilicity potential profile in the molecular environment. Instead of using a l/r- or an exponential distance law between the atomic coordinates and a point on the molecular surface, a new distance dependency is introduced for the calculation of an MLP-value on the solvent-accessible surface of the molecule. In the present formalism the Crippen values (introduced for atoms in their characteristic structural environment) are 'projected' onto the van der Waals surface of the molecule by a special weighting procedure. This guarantees that only those atomic fragments contribute significantly to the surface values that are in the close neighbourhood of the surface point. This procedure not only works for small molecules but also allows the characterization of the surfaces of biological macromolecules by means of local lipophilicity. Lipophilic and hydrophilic domains can be recognized by visual inspection of computer-generated images or by computational procedures using fuzzy logic strategies. Local hydrophobicities on different molecular surfaces can be quantitatively compared on the basis of the present approach.
An algorithm for the calculation of local and global curvatures of molecular surfaces is presented. The analysis is based on a surface representation as a set of points in 3-D space (“dotted surface” representation). The surface data are used to subdivide the surfac into domains with different curvatures. All domains are characterized by a reference point with a corresponding curvature profile specifiying the topological properties in its neighborhood. The curvature profiles provide a method for a systematic comparison of the shapes of different molecules. Such a strategy is important for the treatment of molecular recognition problems. The enzyme-inhibitor complex trypsin/BPTI was chosen to demonstrate the scopes of the method.
An algorithm has been developed that can be used to divide triangulated molecular surfaces into distinct domains on the basis of physical and topographical molecular properties. Domains are defined by a certain degree of homogeneity concerning one of these properties. The method is based on fuzzy logic strategies, thus taking into consideration the smooth changes of the properties considered along complex macromolecular surfaces. Scalar qualities assigned to every node point on a triangulated surface are translated into linguistic variables, which can then be processed using a special fuzzy dissimilarity operator.
Methoden zur computerunterstützten Untersuchung selektiver Oberflächeneigenschaften von Proteinen
(1993)
This paper presents an overview on and reports on early experiences of the European ACTS project AC089 called „Distributed Video Production (DVP)“ which started in late 1995. Central to DVP are distributed pilot applications for professional digital video production over ATM broadband networks (LAN and WAN). Distributed video production refers to situations where the cameras, recorders, switches, mixers and other equipment used in video production (or post-production) are located at several sites linked by high bandwidth network connections. The DVP project investigates requirements of broadcasters for several forms of distributed video production and runs a series of trials of distributed virtual studios, distributed rehearsals and remote video editing and retrieval. Together with North American partners a transatlantic broadband ATM link will be tested for distributed virtual reality simulations. This paper reports about two initial tests with a German public broadcaster and the German Telekom. DVP project partners are GMD and about 20 broadcasters, computer and video equipment manufacturers, and video production companies. More information can be obtained from http://viswiz.gmd.de/DVP
Distributed Video Production
(1996)
Video production is inherently distributed: Broadcasters are physically distributed over several sites and studios, they increasingly outsource video production and post-production to specialized studios or upcoming virtual studios. Thus there is an increasing demand for the enabling technology for distributed video production.
Imagine a person navigating on the trackball of a mouse - it would need full body control. In this article we describe the Virtual Balance, an input device for a responsive virtual environment. This device is driven by weight shift on a small platform and does neither require special training nor wearing uncomfortable equipment. The Virtual Balance aims at intuitive navigation through complex 3D space. It can be used to skate or fly like on a magic carpet through a virtual world. With shifts of body posture the navigator controls speed and direction of his/her movement in the model world, which is calculated from the changing pressure on three weight cells under the platform. Different fields of application are presented, showing scenarios already realized as well as a variety of possibilities for future use.
In this paper we present a new storytelling approach, called Hypermedia Novel (HYMN), that extends the classical narration concept of a story. We develop an underlying modular concept – the narration module – that facilitates a new manner of reception as well as creation of a story. The HYMN focuses on the recipient and his role of consuming a story and a heterogeneous group of creative authors by providing narration modules and their interfaces without defining the granularity of the modules. Using several kinds ofmultimedia elements and a hyperlink structure, we present a first demonstrator that implements this new concept. We also discuss improvements, e.g. MPEG-4/7, that support both reception by the audience, and the process of creating the story by a dispersed team of authors.
Benches and Caves
(1998)
Virtual environments (VE) now have come into age. Following the head bounded technology of the first days, industrial applications in the virtual reality labs of the automotive industry are now using stereo projection type systems like standard single screens, multiple screens, responsive workbenches and also cave-like-projection systems.
