Visualization of the entire surface of a protein by cartographic projection

A minicomputer based system for the determination and schematic representation of protein surfaces is described. The algorithms are based on the atomic coordinates of globular protein molecules of the Brookhaven Protein Data Bank. Using a cartographic projection a normalized graphic representation is obtained of the amino acid residues located on the surface of the considered protein. The programs are written in FORTRAN IV (surface determination) and BASIC (graphic representation).     

Light scattering from filaments

Photorealistic visualization of a huge number of individual filaments like in the case of hair, fur, or knitwear is a challenging task: Explicit rendering approaches for simulating radiance transfer at a filament get totally impracticable with respect to rendering performance and it is also not obvious how to derive efficient scattering functions for different levels of (geometric) abstraction or how to deal with very complex scattering mechanisms. We present a novel uniform formalism for light scattering from filaments in terms of radiance, which we call the bidirectional fiber scattering distribution function (BFSDF). We show that previous specialized approaches, which have been developed in the context of hair rendering, can be seen as instances of the BFSDF. Similar to the role of the BSSRDF for surface scattering functions, the BFSDF can be seen as a general approach for light scattering from filaments, which is suitable for deriving approximations in a canonic and systematic way. For the frequent cases of distant light sources and observers, we deduce an efficient far field approximation (bidirectional curve scattering distribution function, BCSDF). We show that on the basis of the BFSDF, parameters for common rendering techniques can be estimated in a non-ad-hoc, but physically-based way     

Die Kapazität von Kreisplattenkondensatoren bei beliebigem Abstand und beliebiger Plattendicke mit und ohne Dielektrikum

Electrical Engineering - Nach einer Übersicht über die Kapazitätsberechnungen nach Kirchhoff, Kottler, v. Guttenberg und Pflügel wird eine neue Formel für die...     

Non‐Local Image Reconstruction for Efficient Computation of Synthetic Bidirectional Texture Functions

Visual prototyping of materials is relevant for many computer graphics applications. A large amount of modelling flexibility can be obtained by directly rendering micro‐geometry. While this is possible in principle, it is usually computationally expensive. Recently, bidirectional texture functions (BTFs) have become popular for efficient photorealistic rendering of surfaces. We propose an efficient system for the computation of synthetic BTFs using Monte Carlo path tracing of micro‐geometry. We observe that BTFs usually consist of many similar apparent bidirectional reflectance distribution functions. By exploiting structural similarity we can reduce rendering times by one order of magnitude. This is done in a process we call non‐local image reconstruction, which has been inspired by non‐local means filtering. Our results indicate that synthesizing BTFs is highly practical and may currently only take a few minutes for BTFs with 70 × 70 viewing and lighting directions and 128 × 128 pixels.     

Runde und rechteckige Hohlleiter und ihre Ersatzschaltungen

Ohne ZusammenfassungMitteilung aus dem Zentral-Laboratorium der Siemens u. Halske AG.Mit 12 Textabbildungen.Erweiterter Teil eines Vortrages im Elektrotechnischen Kolloquium der Technischen Hochschulen Karlsruhe und Aachen.     

A Fuzzy Rule‐based Model for the Assessment of Macrobenthic Habitats under Hydropeaking Impact

Hydropeaking presents one of the large impacts on river ecology and is gaining importance because of an increasinlgy volatile energy market with high portions of new renewable energies dependent on local climate conditions. This study presents the application of a fuzzy logic model for the investigation of macrobenthic habitats under hydropeaking conditions in the Norwegian river Surna. Preference data of the three taxa Baetis rhodani, Hydroptila spp. and Allogamus auricollis with distinctively different habitat requirements related to near‐bottom flow forces (high/low forces, and narrow range) are used. These data are transferred into the multivariate fuzzy rule‐based physical habitat model Computer Aided Simulation of Instream flow and Riparia in order to integrate water depth and river bed substrate as additional parameters. Permanently available habitats (persistent habitats) are assessed for different scenarios of hydropeaking operation. It is found that the amount of persistently high‐quality habitat is closely related to the size and range of fluctuations in hydraulic conditions occuring during hydropeaking events. Effects are much more distinct for species with a narrow range of hydraulic preference. The integration of water depth in the simulations has a noticable impact on the amount and quality of predicted habitats. Substrate conditions in the investigation site are homogeneous and, in the specific case considered, do not have a significant impact. The study suggests persistent habitats as a suitable indicator of hydropeaking impact on organisms with low mobility. The persistent habitat approach takes into account that organisms with a low mobility and a distinct range of tolerance related to hydraulic stress tend to settle in areas with permanently stable conditions. Multivariate aspects are accounted through the fuzzy rule‐based approach and do clearly affect habitat predictions. Habitat requirements of species particularly sensitive to hydropeaking are proposed for the investigation and application in the future. Copyright © 2016 John Wiley & Sons, Ltd.