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111.
Friedl-Vallon F Maucher G Seefeldner M Trieschmann O Kleinert A Lengel A Keim C Oelhaf H Fischer H 《Applied optics》2004,43(16):3335-3355
MIPAS-B2 is a balloon-borne limb-emission sounder for atmospheric research. The heart of the instrument is a Fourier spectrometer that covers the mid-infrared spectral range (4-14 microns) and operates at cryogenic temperatures. Essential for this application is the sophisticated line-of-sight stabilization system, which is based on an inertial navigation system and is supplemented with an additional star reference system. The major scientific benefit of the instrument is the simultaneous detection of complete trace gas families in the stratosphere without restrictions concerning the time of day and viewing directions. The specifications, the design considerations, the actual realization of the instrument, and the results of characterization measurements that have been performed are described. 相似文献
112.
Entwicklung verschiedener Kalorimeteranordnungen zur Bestimmung des Wärmeinhalts zwischen 0 und 25, 25 und 65, 25 und 1400 und zwischen 25 und 1720 °C. Die mittlere und wahre spezifische Wärme von Schmelzkalk (Kristallkalk). Vergleich der Ergebnisse mit Angaben des Schrifttums über gebrannten Kalk. 相似文献
113.
Bestimmung des Parameters pe′ (tion = 0,5) zur Kennzeichnung der Elektronenteilleitfähigkeit in festen Elektrolyten. Anwendung einer abgewandelten Polarisationsmethode mit EMK-Messung. Angabe der Parameter pe′ für Festelektrolyte aus ZrO2 mit einem Molenbruch xCaO = 0,14 und aus ThO2 mit einem Molenbruch bei Temperaturen zwischen 1200 und 1650 °C. Berechnung korrigierter Eichkurven für die elektrochemische Messung der Sauerstoffaktivitäten in Stahlschmelzen. Empfehlung einer bevorzugten Anwendung von ThO2(Y2O3)-Elektrolyten zur Messung kleinster Sauerstoffaktivitäten. 相似文献
114.
Computer-controlled mechanical simulation of the artificially ventilated human respiratory system 总被引:3,自引:0,他引:3
Mesić S Babuska R Hoogsteden HC Verbraak AF 《IEEE transactions on bio-medical engineering》2003,50(6):731-743
A mechanical lung simulator can be used to simulate specific lung pathologies, to test lung-function equipment, and in instruction. A new approach to mechanical simulation of lung behavior is introduced that uses a computer-controlled active mechatronic system. The main advantage of this approach is that the static and dynamic properties of the simulator can easily be adjusted via the control software. A nonlinear single-compartment mathematical model of the artificially ventilated respiratory system has been derived and incorporated into the simulator control system. This model can capture both the static and dynamic compliance of the respiratory system as well as nonlinear flow-resistance properties. Parameters in this model can be estimated by using data from artificially ventilated patients. It is shown that the simulation model fits patient data well. This mathematical model of the respiratory system was then matched to a model of the available physical equipment (the simulator, actuators, and the interface electronics) in order to obtain the desired lung behavior. A significant time delay in the piston motion control loop has been identified, which can potentially cause oscillations or even instability for high compliance values. Therefore, a feedback controller based on the Smith-predictor scheme was developed to control the piston motion. The control system, implemented on a personal computer, also includes a user-friendly interface to allow easy parameter setting. 相似文献
115.
Schwaighofer A Tresp V Mayer P Krause A Beuthan J Rost H Metzger G Müller GA Scheel AK 《IEEE transactions on bio-medical engineering》2003,50(3):375-382
We describe a classification system for a novel imaging method for arthritic finger joints. The basis of this system is a laser imaging technique which is sensitive to the optical characteristics of finger joint tissue. From the laser images acquired at baseline and follow-up, finger joints can automatically be classified according to whether the inflammatory status has improved or worsened. To perform the classification task, various linear and kernel-based systems were implemented and their performances were compared. Based on the results presented in this paper, we conclude that the laser-based imaging permits a reliable classification of pathological finger joints, making it a sensitive method for detecting arthritic changes. 相似文献
116.
Cory J. Rupp Anton Evgrafov Kurt Maute Martin L. Dunn 《Structural and Multidisciplinary Optimization》2007,34(2):111-121
We develop a topology optimization approach to design two- and three-dimensional phononic (elastic) materials, focusing primarily
on surface wave filters and waveguides. These utilize propagation modes that transmit elastic waves where the energy is contained
near a free surface of a material. The design of surface wave devices is particularly attractive given recent advances in
nano- and micromanufacturing processes, such as thin-film deposition, etching, and lithography, which make it possible to
precisely place thin film materials on a substrate with submicron feature resolution. We apply our topology optimization approach
to a series of three problems where the layout of two materials (silicon and aluminum) is sought to achieve a prescribed objective:
(1) a grating to filter bulk waves of a prescribed frequency in two and three dimensions, (2) a surface wave device that uses
a patterned thin film to filter waves of a single or range of frequencies, and (3) a fully three-dimensional structure to
guide a wave generated by a harmonic input on a free surface to a specified output port on the surface. From the first to
the third example, the resulting topologies increase in sophistication. The results demonstrate the power and promise of our
computational framework to design sophisticated surface wave devices. 相似文献
117.
118.
Chunhua Shen Peng Wang Sakrapee Paisitkriangkrai Anton van den Hengel 《International Journal of Computer Vision》2013,103(3):326-347
Cascade classifiers are widely used in real-time object detection. Different from conventional classifiers that are designed for a low overall classification error rate, a classifier in each node of the cascade is required to achieve an extremely high detection rate and moderate false positive rate. Although there are a few reported methods addressing this requirement in the context of object detection, there is no principled feature selection method that explicitly takes into account this asymmetric node learning objective. We provide such an algorithm here. We show that a special case of the biased minimax probability machine has the same formulation as the linear asymmetric classifier (LAC) of Wu et al. (linear asymmetric classifier for cascade detectors, 2005). We then design a new boosting algorithm that directly optimizes the cost function of LAC. The resulting totally-corrective boosting algorithm is implemented by the column generation technique in convex optimization. Experimental results on object detection verify the effectiveness of the proposed boosting algorithm as a node classifier in cascade object detection, and show performance better than that of the current state-of-the-art. 相似文献
119.
Xu Wang Ali Saberi Anton A. Stoorvogel Sandip Roy Peddapullaiah Sannuti 《International journal of control》2013,86(10):1870-1881
This article considers discrete-time linear time-invariant systems subject to input and state constraints. It is shown that in the recoverable region (which is the largest domain of attraction that is theoretically achievable) system can be semi-globally stabilised by nonlinear feedbacks while satisfying the constraints. Moreover, the recoverable region for the given system is constructed by constructing the same, however, for a reduced-order subsystem of the given system. Such a reduction in the order or dimension of the system generally leads to a considerable simplification in the computational effort. 相似文献
120.
Souhail Boussetta Gianpaolo Balsamo Anton Beljaars Tomas Kral Lionel Jarlan 《International journal of remote sensing》2013,34(9-10):3520-3542
The leaf area index (LAI), defined as the one-sided green leaf area per unit ground area, is used in many numerical weather prediction (NWP) models as an indicator of the vegetation development state, which is of paramount importance to characterize land evaporation, photosynthesis, and carbon-uptake processes. LAI is often simply represented by lookup tables, dependent on the vegetation type and seasons. However, global LAI datasets derived from remote sensing observations have more recently become available. These products are based on sensors such as the Advanced Very High Resolution Radiometer (AVHRR) or the Moderate Resolution Imaging Spectroradiometer (MODIS), onboard polar orbiting satellites that can cover the entire globe within typically 3 days and with a spatial resolution of the order of 1 km. We examine the meteorological impact of satellite-derived LAI products on near-surface air temperature and humidity, which comes both from the stomatal transpiration of leaves and from the intercepted water on the surface of leaves, re-evaporating into the atmosphere. Two distinct monthly LAI climatology datasets derived respectively from AVHRR and MODIS sensors are tested. A set of forecasts and data assimilation experiments with the integrated forecasting system of the European Centre for Medium-range Weather Forecasts is performed with the monthly LAI climatology datasets as opposed to a vegetation-dependent constant LAI. The monthly LAI is shown to improve the forecasts of near-surface (screen-level) air temperature and relative humidity through its effect on evapotranspiration, with the largest impact obtained over needleleaf forests, crops, and grassland. At longer time-scales, the introduction of the monthly LAI is shown to have a positive impact on the model climate particularly during the boreal spring, where the LAI climatology has a large seasonal cycle. 相似文献