Wavelet methods for the solution of wave-body problems

Fredholm integral equations of the second kind that arise in wave analysis of floating bodies are solved using a wavelet method. The two-dimensional linear wave-body problem for arrays of rectangular cylinders floating in the free surface of an otherwise unbounded fluid is considered. Both spline wavelets and the Daubechies wavelets with adaption to an interval are used as basis functions. An a priori compression strategy taking into account the singularities of the kernel of the integral equation, which arise at the corners of the geometry, is developed. The algorithm is O(n), where n is the number of unknowns. Computations of the hydrodynamic properties of the cylinders using the compression strategy are performed. The strategy is found to work well. A very high compression rate is obtained, still keeping a high accuracy of the computations. The accuracy of the potential close to the corners (singular points) is examined in a special case where an analytical solution is available.     

Fünfring-Cycloamidine – Neue farbige Heterocyclen mit ungewöhnlichen Eigenschaften. II. Molekül- und Elektronenstruktur

5-Ring-Cycloamidines – Deeply Colored Heterocycles with Unusual Properties. II. Molecular- and Electronic Structure The crystal and molecular structure of two N,N′-aryl-5-amino-imidazole-4-imides were detected by X-ray analysis. The structural parameters are discussed in conjunction with theoretical data obtained by density functional and ab initio quantum theory. The interpretation of the molecular structures derived from the X-ray diffraction study is made more difficult by statistic disorder or by enclosure of water in the crystal. The theory predicts a planar 5-amino-imidazole-4-imide parent structure with an energy barrier to H-transfer of about 25 kcal/mol (DFT RB3LYP/6-311+G** and ab initio G2(MP2) calculations). The CC bond of the five-membered ring is exceedingly long. CC-bond length elongation is also reported for oxalbisamidine. The structure of the parent compound is discussed in terms of polymethinic and antiaromatic substructures. Weinholds's Natural Bond Orbital (NBO) scheme and Natural Resonance Theory (NRT) as well as Schleyer's criterion of the Nucleus Independent Chemical Shift (NICS) is consulted to reveal the very nature of the unique bond system.     

Production of Structure Components with Selective Properties by means of Action Media based Cold Forming

Minimising a metallic component's weight can be achieved by either using lightweight alloys or by improving the component's properties. In both cases, the material formability affects the utilisability for mass production processes. Most of the high‐strength materials show a material‐restricted formability and are difficult to forge. The formability of a material is described by its maximum forming limit. Large plastic strains can lead to mechanical damage within the material. A promising approach of handling low ductile, high‐strength alloys in a forming process is deformation under superimposed hydrostatic pressure by active media. In the present study, the influence of superimposed hydrostatic pressure on the flow stress is analysed as well as the forming ability for different sample geometries at different hydrostatic pressure and temperature levels. The experimental results show that the superimposed pressure has no influence on the plastic deformation, nor does a pressure dependent near‐surface material hardening occur. Nevertheless, the formability is improved with increasing hydrostatic pressure. The relative gain at room temperature and increase in the superimposed pressure from 0 bar to 600 bar for tested materials was at least 140 % and max. 220 %. Therefore, a cold forming process under superimposed pressure is developed to produce structure components with selective properties. For example, the gain in formability will be used to enlarge local plastic strains to higher limits resulting in higher local strain hardening and hardness. This offers new design possibilities with selectively adjusted local structure or structure component properties, especially adapted to their technical application. Additionally, by applying damage models, finite‐element analysis is used in order to predict damage occurring in the cold forming process under superimposed hydrostatic pressure for various sample geometries.     

The role of automatic obesity stereotypes in real hiring discrimination.

This study examined whether automatic stereotypes captured by the implicit association test (IAT) can predict real hiring discrimination against the obese. In an unobtrusive field experiment, job applications were sent to a large number of real job vacancies. The applications were matched on credentials but differed with respect to the applicant's weight. Discriminatory behavior was quantified by the extent to which the hiring managers invited normal-weight versus obese applicants to a job interview. Several months after the behavioral data were obtained, the hiring managers completed an obesity IAT and explicit hiring preference measures. Only the IAT scores reliably predicted interview decisions. More specifically, hiring managers holding more negative automatic stereotypes about the obese were less likely to invite an obese applicant for an interview. The present research is the first to show that automatic bias predicts labor market discrimination against obese individuals. Practical implications are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Internal comparisons in everyday life.

According to the internal/external frame of reference (I/E) model (H. W. Marsh, 1986), students not only compare their own abilities in a domain with those of other students (social comparison), they also compare their own achievements in different domains (internal comparison). The main purpose of this study was to investigate internal comparison processes in everyday life using an introspective methodology. Over 2 weeks, 67 university students (Study 1) and 65 high school students (Study 2) using a diary instrument recorded more upward than downward internal comparisons, most of them triggered by academic achievement situations. In both studies, multilevel analyses showed links between the direction of comparison and affective state: (a) upward internal comparisons were associated with negative mood states; (b) downward internal comparisons were associated with positive mood states; (c) upward internal comparisons increased positive and decreased negative mood states; (d) downward internal comparisons decreased positive and increased negative mood states. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Image Compression and Transmission Through a Low-Rate Ultrasonic Link in Subsea Telerobotic Applications

This paper describes a progressive data compression algorithm for subsea gray-level image (data) transmission through a low rate ultrasonic link in a telerobotics system. The proposed image compression algorithm is based on JPEG, and has been modified for a specific subsea application, where the communication bit rate is confined to 100–200 bits/s and a frequent updating of reconstructed images is required.The experimental result based on 23 real imagesshows that the proposed image data compression algorithmperforms better than JPEG when images are reconstructed from asmall amount of data. The transmission error effect andcomputational complexity have also been analysed with respect tothe proposed algorithm.     

How have we arrived at the present state of knowledge in process control? Is there a lesson to be learned?

The utilization of the results of control theory in the process control field has been lagging behind other application fields such as aerospace by many years. It is argued that the availability of high capacity computing at low price will change this situation and that new powerful control techniques can now be implemented in process control.     

Sorting networks on FPGAs

Computer architectures are quickly changing toward heterogeneous many-core systems. Such a trend opens up interesting opportunities but also raises immense challenges since the efficient use of heterogeneous many-core systems is not a trivial problem. Software-configurable microprocessors and FPGAs add further diversity but also increase complexity. In this paper, we explore the use of sorting networks on field-programmable gate arrays (FPGAs). FPGAs are very versatile in terms of how they can be used and can also be added as additional processing units in standard CPU sockets. Our results indicate that efficient usage of FPGAs involves non-trivial aspects such as having the right computation model (a sorting network in this case); a careful implementation that balances all the design constraints in an FPGA; and the proper integration strategy to link the FPGA to the rest of the system. Once these issues are properly addressed, our experiments show that FPGAs exhibit performance figures competitive with those of modern general-purpose CPUs while offering significant advantages in terms of power consumption and parallel stream evaluation.