Listener-based analysis of surface importance for acoustic metrics

Acoustic quality in room acoustics is measured by well defined quantities, like definition, which can be derived from simulated impulse response filters or measured values. These take into account the intensity and phase shift of multiple reflections due to a wave front emanating from a sound source. Definition (D50) and clarity (C50) for example correspond to the fraction of the energy received in total to the energy received in the first 50 ms at a certain listener position. Unfortunately, the impulse response measured at a single point does not provide any information about the direction of reflections, and about the reflection surfaces which contribute to this measure. For the visualization of room acoustics, however, this information is very useful since it allows to discover regions with high contribution and provides insight into the influence of all reflecting surfaces to the quality measure. We use the phonon tracing method to calculate the contribution of the reflection surfaces to the impulse response for different listener positions. This data is used to compute importance values for the geometry taking a certain acoustic metric into account. To get a visual insight into the directional aspect, we map the importance to the reflecting surfaces of the geometry. This visualization indicates which parts of the surfaces need to be changed to enhance the chosen acoustic quality measure.We apply our method to the acoustic improvement of a lecture hall by means of enhancing the overall speech comprehensibility (clarity) and evaluate the results using glyphs to visualize the clarity (C50) values at listener positions throughout the room.     

Adaptation of an automotive dialogue system to users’ expertise and evaluation of the system

Spoken dialogue systems (SDSs) can be used to operate devices, e.g. in the automotive environment. People using these systems usually have different levels of experience. However, most systems do not take this into account. In this paper, we present a method to build a dialogue system in an automotive environment that automatically adapts to the user’s experience with the system. We implemented the adaptation in a prototype and carried out exhaustive tests. Our usability tests show that adaptation increases both user performance and user satisfaction. We describe the tests that were performed, and the methods used to assess the test results. One of these methods is a modification of PARADISE, a framework for evaluating the performance of SDSs [Walker MA, Litman DJ, Kamm CA, Abella A (Comput Speech Lang 12(3):317–347, 1998)]. We discuss its drawbacks for the evaluation of SDSs like ours, the modifications we have carried out, and the test results.

Quantitative comparison between full-spectrum and filter-based imaging in hyperspectral fluorescence microscopy

We implement a filterless illumination scheme on a hyperspectral fluorescence microscope to achieve full-range spectral imaging. The microscope employs polarisation filtering, spatial filtering and spectral unmixing filtering to replace the role of traditional filters. Quantitative comparisons between full-spectrum and filter-based microscopy are provided in the context of signal dynamic range and accuracy of measured fluorophores' emission spectra. To show potential applications, a five-colour cell immunofluorescence imaging experiment is theoretically simulated. Simulation results indicate that the use of proposed full-spectrum imaging technique may result in three times improvement in signal dynamic range compared to that can be achieved in the filter-based imaging.     

磁悬浮无轴承电动机发展、应用和前景

综述了磁悬浮无轴承电动机起源及发展历史，介绍了磁悬浮无轴承电动机的基本原理，详细论述了磁悬浮无轴承电动机在半导体工业、化工工业及生物工程等领域的应用特点和意义，展望了我国研究和应用磁悬浮无轴承电动机前景。     

Modeling of flashing-induced instabilities in the start-up phase of natural-circulation BWRs using the two-phase flow code FLOCAL

This paper reports on the modeling and simulation of flashing-induced instabilities in natural-circulation systems, with special emphasis on natural-circulation boiling water reactors (BWRs). For the modeling the 4-equation two-phase model FLOCAL [Rohde, U., 1986. Ein teoretisches Modell fur Zweiphasen-stromungen in wassergekulthen Kernreaktoren und seine Anwendung zur Analyse des Naturumlaufs im Heizreaktor AST-500. Ph.D. dissertation, Akademie der Wissenschaften der DDR, Dresden], developed at the Forschungszentrum Rossendorf (FZR, Germany), has been used. The model allows for the liquid and vapor to be in thermal non-equilibrium and, via drift-flux models, to have different velocities.The phenomenology of the instability has been studied and the dominating physical effects have been determined. The results of the simulations have been compared qualitatively and quantitatively with experiments [Manera, A., van der Hagen, T.H.J.J., 2003. Stability of natural-circulation-cooled boiling water reactor during start up: experimental results. Nuc. Technol., 143] that have been carried out within the framework of a European project (NACUSP) on the CIRCUS facility. The facility, built at the Delft University of Technology in The Netherlands, is a water/steam 1:1 height-scaled loop of a typical natural-circulation-cooled BWR.     

FLOW STRESS DATA FOR FINITE ELEMENT SIMULATION IN METAL CUTTING: A PROGRESS REPORT ON MADAMS

To obtain reliable results from Finite Element (FE) simulation of machining processes, it is necessary to have as input the properties of the workpiece and tool materials as well as the characteristics of the tool/chip interface. These input parameters include physical and thermal data, friction and heat transfer, and most importantly the flow stress of the workpiece material under high strain, strain rate and temperature conditions that exist during the process. This paper presents a brief review of FE simulation of machining processes, a review of the approaches used to determine the flow stress at high deformation rate, and the examples of different constitutive equations used to represent such flow stress data. A material property database (MADAMS) has been developed and provides useful information to conduct simulations of machining processes. The main objectives of the material database are to assist researchers in areas of machining analysis and material modeling and to promote collaboration between various international research groups.     

Asymptotic Coupling Coefficients of Well-separated Single-mode Optical Waveguides

Abstract

Simple general formulae for the coupling coefficients of the fundamental modes on well-separated parallel optical waveguides are derived. The calculation merely requires accurate knowledge of the propagation constants and core fields of the modes on the individual waveguides, while the far-from-core fields need not be known. Results for coupled circular fibres are identical with the asymptotic expansions of previously derived exact coupling coefficients. Analytical expressions for the coupling coefficients between the fundamental modes on identical weakly guiding channel waveguides are obtained.     

Investigation of the effects of a variation of fuel assembly position on the ex-core neutron flux detection in a PWR

This work shows the impact of potential displacements of the fuel assembly positions in the reactor core on the signal values of the ex-core instrumentation of a pressurized water reactor in order to understand in detail the impact on the calibration factor of ex-core detectors. This was done with a range of Monte Carlo calculations that simulated the detailed geometrical effect by stepwise changing of the positions of fuel assemblies for selected, conservative scenarios. First, criticality calculations were carried out for the chosen core configurations, and corresponding surface sources on the core barrel were determined. In these calculations, the distances were varied between the fuel assemblies which were in the line of sight of the ex-core instrumentation. A maximal change of the fluxes on the surface of the core barrel of 4%/mm could be calculated under conservative assumptions for the combination of displaced fuel assemblies. In addition, a dependence of this effect as a function of cycle burn-up was analyzed. In a second step, transport calculations for the ionization chambers were performed using the surface sources. An increase of the reaction rate at the chambers of up to 3%/mm has been calculated.     

Soft Matter Technology at KIT: Chemical Perspective from Nanoarchitectures to Microstructures

Bioinspiration has emerged as an important design principle in the rapidly growing field of materials science and especially its subarea, soft matter science. For example, biological cells form hierarchically organized tissues that not only are optimized and designed for durability, but also have to adapt to their external environment, undergo self‐repair, and perform many highly complex functions. Being able to create artificial soft materials that mimic those highly complex functions will enable future materials applications. Herein, soft matter technologies that are used to realize bioinspired material structures are described, and potential pathways to integrate these into a comprehensive soft matter research environment are addressed. Solutions become available because soft matter technologies are benefitting from the synergies between organic synthesis, polymer chemistry, and materials science.