Optical receiver IC for CD/DVD/blue-laser application

In this paper, an optoelectronic receiver IC for CD, DVD, and Blue-Laser optical data storage applications is presented. The IC was developed in a 0.5-/spl mu/m BiCMOS technology with integrated PIN photodiodes. It includes a new architecture of high-speed and low-noise variable gain transimpedance amplifiers witch current preamplifier input. The amplifier transimpedance gain is programmable over a gain range of 130 /spl Omega/ to 270 k/spl Omega/ by a serial interface. The amplifier small-signal bandwidth is 260 MHz for the highest gain, which gives a gain-bandwidth product of 70 THz/spl Omega/ and a sensitivity improvement by a factor of 2 compared to published OEICs. The amplifiers support a special write/clip mode which realizes a nonlinear gain reduction for high input signals. The output voltage buffers are 130-/spl Omega/ impedance matched for optimized data transmission over a flex cable. The impedance is generated by active-impedance synthesis to increase the output dynamic range.     

A generic structure-from-motion framework

We introduce a generic structure-from-motion approach based on a previously introduced, highly general imaging model, where cameras are modeled as possibly unconstrained sets of projection rays. This allows to describe most existing camera types including pinhole cameras, sensors with radial or more general distortions, catadioptric cameras (central or non-central), etc. We introduce a structure-from-motion approach for this general imaging model, that allows to reconstruct scenes from calibrated images, possibly taken by cameras of different types (cross-camera scenarios). Structure-from-motion is naturally handled via camera independent ray intersection problems, solved via linear or simple polynomial equations. We also propose two approaches for obtaining optimal solutions using bundle adjustment, where camera motion, calibration and 3D point coordinates are refined simultaneously. The proposed methods are evaluated via experiments on two cross-camera scenarios—a pinhole used together with an omni-directional camera and a stereo system used with an omni-directional camera.     

Simulation of deposition and clearance of inhaled particles in central human airways

In this study local distributions of deposited inhaled particles such as radon progenies in realistic human airway bifurcation models of bronchial generations one to six are computed for different geometries, inlet flow profiles, flow rates and particle sizes with computational fluid particle dynamics methods. The movement of the mucus layer in the large central human airways is also simulated by computational fluid dynamic techniques. There is experimental evidence that bronchogenic carcinomas mainly originate at the central zone of the large airway bifurcations, where primary hot-spots of deposition have been found. However, current lung deposition models do not take into consideration the inhomogeneity of deposition within the airways. The inhomogeneous movement of the mucus layer may strongly influence the effect of primary deposition. On the basis of our results, both the deposition and the clearance patterns are highly non-uniform, especially in the vicinity of the carinal ridge of the bifurcations.     

Investitionsgüterhersteller als Anbieter industrieller Lösungen – Bestandsaufnahme des Wandels anhand einer Umfrage

The article is dedicated to the empirical exploration of solution providers in the German capital goods industry. A model – consisting of six principles and success factors for solution management – is used to draw conclusions on the relevance and the need for action to manage the transition towards being a solution provider. The answers from 99 medium-sized companies reveal the following results: 1.) The solution concept offers the opportunity to gain competitive advantage 2.) The potential of providing solutions has been recognised, yet the implementation is lagging behind 3.) A consistent solution management process is a prerequisite for success 4.) Appropriate methods and tools are required along the whole process.     

OCEANcode: The complete set of algorithms and models for the level_2 processing of European CZCS historical data

A complete set of algorithms and models for the level_2 processing of the European CZCS historical data was integrated in the OCEANcode software package. The OCEANcode allows the calibration of the sensor-recorded signal taking into account the instrument sensitivity loss; the correction of the calibrated signal for atmospheric contamination and derive sub-surface reflectances; and then the estimation of the concentration of water constituents. The atmospheric correction is performed on the basis of a reflectance-model-based algorithm. The Rayleigh correction is applied consistently for all water pixels, using a multiple scattering approach, and introducing atmospheric pressure and Ozone concentration data in the computation. The marine aerosol correction uses a pixel-by-pixel iterative procedure, allowing successive estimates of both the marine reflectance in the red spectral region (670nm) and the Angstrom exponent, which links simple wavelengths ratios to reflectance ratios. For case 1 waters, the optical properties of which are essentially dominated by planktonic pigments, the interrelations between marine reflectances and reflectance ratios at various wavelengths are derived from modelled calculations. For identified case 2 waters, where water constituents other than planktonic pigments (i.e. dissolved organics and suspended sediments) dominate the water optical properties, the evaluation of marine reflectances is approximated by means of interpolated Angstrom exponent values computed over case 1 water pixels and of empirical relationships derived from in situ measurements. The computation of chlorophyll-like pigments is performed with algorithms based on blue/green (443-550nm) reflectance ratios, for lower pigment concentration, or on green/green (520-550nm) reflectance ratios, for higher pigment concentration. As for the case of atmospheric corrections, the inter-relations between pigment concentration and reflectance ratios are model-derived for case 1 waters, and empirically determined for case 2 waters.     

Sparse Approximation and the Pursuit of Meaningful Signal Models With Interference Adaptation

In the pursuit of a sparse signal model, mismatches between the signal and the dictionary, as well as atoms poorly selected by the decomposition process, can diminish the efficiency and meaningfulness of the resulting representation. These problems increase the number of atoms needed to model a signal for a given error, and they obscure the relationships between signal content and the elements of the model. To increase the efficiency and meaningfulness of a signal model built by an iterative descent pursuit, such as matching pursuit (MP), we propose integrating into its atom selection criterion a measure of interference between an atom and the model. We define interference and illustrate how it describes the contribution of an atom to modeling a signal. We show that for any nontrivial signal, the convergent model created by MP must have as much destructive as constructive interference, i.e., MP cannot avoid correction in the signal model. This is not necessarily a shortcoming of orthogonal variants of MP, such as orthogonal MP (OMP). We derive interference-adaptive iterative descent pursuits and show how these can build signal models that better fit the signal locally, and reduce the corrections made in a signal model. Compared with MP and its orthogonal variants, our experimental results not only show an increase in model efficiency, but also a clearer correspondence between the signal and the atoms of a representation.      

Collective-reward based approach for detection of semi-transparent objects in single images

Most computer and robot vision algorithms, be it for object detection, recognition, or reconstruction, are designed for opaque objects. Non-opaque objects have received less attention, although various special cases have been the subject of research efforts, especially the case of specular objects. The main objective of this paper is to provide a research work in the case of semi-transparent objects, i.e. objects that are transparent but also reflect light, typically objects made of glass. They are rather omnipresent in man-made environments (especially, windows and doors). Detection of these objects provides important information that can be used in a robot’s navigational strategies such as obstacle avoidance, detection of oil/water spills on the floor, localization, etc. In order to achieve the detection of semi-transparent objects we developed a novel approach using a collective-reward based technique on an image captured by an uncalibrated camera. Several experiments were conducted over different scenarios to test the efficacy of the algorithm.     

Amorphous Silicon Thin-Film Transistor Backplanes Deposited at 200 °C on Clear Plastic for Lamination to Electrophoretic Displays

The transition of thin-film transistor (TFT) backplanes from rigid plate glass to flexible substrates requires the development of a generic TFT backplane technology on a clear plastic substrate. To be sufficiently stable under bias stress, amorphous-silicon (a-Si:H) TFTs must be deposited at elevated temperatures, therefore the substrate must withstand high temperatures. We fabricated a-Si:H TFT backplanes on a clear plastic substrate at 200degC. The measured stability of the TFTs under gate bias stress was superior to TFTs fabricated at 150degC. The substrate was dimensionally stable within the measurement resolution of 1, allowing for well-aligned 8 times 8 and 32 times 32 arrays of pixels. The operation of the backplane is demonstrated with an electrophoretic display. This result is a step toward the drop-in replacement of glass substrates by plastic foil.     

Photoluminescence spectroscopy of localized excitons in Si1−xGex

We have recently found that high quantum efficiency can be achieved in strained Si_1−xGe_x alloy layers through the elimination of nonradiative channels. We observed a photoluminescence process in SiGe grown on 〈100232A; silicon by rapid thermal chemical vapor deposition, which was attributed to free excitons localized by random fluctuations in alloy composition. The external quantum efficiency of this process was measured directly for a single Si_0.75Ge_0.25 quantum well and found to be extraordinarily high, about 11.5 ± 2%. In this paper, we present additional data on the localized exciton photoluminescence, including temperature dependence, time decay curves, and effects of sample annealing.     

Simultaneous detection of beta-galactosidase activity and surface antigen expression in viable haematopoietic cells

The quantitation of intracellular beta-galactosidase activity has been described for viable cells. By using the fluorogenic substrate fluorescein-di-beta-D-galactopyranoside (FDG) in conjunction with flow cytometry, the proportion of positive cells as well as the level of expression can be determined. In this paper we describe beta-galactosidase expression in lymphoid and myeloid cells from transgenic mice that widely express beta-galactosidase from an inserted lacZ transgene. Both foetal and adult haematopoietic tissues are able to express beta-galactosidase. The intracellular fluorescence reflecting beta-galactosidase activity can be readily combined with fluorescently labelled antibodies against cell surface antigens. Thus, beta-galactosidase can be used as a marker in transplantation experiments to study the development of lymphoid and myeloid precursor cells.