A method is considered for measuring object quality parameters that can arise through indirect parameters, and in particular electrophysical signals acting on the object. Methods are given for obtaining a mathematical...
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A method is considered for measuring object quality parameters that can arise through indirect parameters, and in particular electrophysical signals acting on the object. Methods are given for obtaining a mathematical model for the measurement procedure and examples are quoted of the method applied with the use of spectrometric characteristics of the object.
The purpose of this study was to determine the optimum tube voltage and amount of added copper (Cu) filtration for processed chest radiographs obtained with an Agfa 75.0 Computed Radiography (CR) system. The contrast-...
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The purpose of this study was to determine the optimum tube voltage and amount of added copper (Cu) filtration for processed chest radiographs obtained with an Agfa 75.0 Computed Radiography (CR) system. The contrast-to-noise ratio (CNR) was measured in the lung, heart/spine and diaphragm compartments of a validated chest phantom using various tube voltages and amounts of Cu filtration. The CNR was derived as a function of air kerma at the CR plate and with the effective dose. As rib contrast can interfere with detection of nodules in chest radiography, a tissue-to-rib ratio (TRR) was derived to investigate which tube voltages suppress the contrast of rib. Although processing algorithms affect the signal and noise in a way that is hard to predict, we found that, for a given set of processing parameters, the CNR was related to the plate air kerma and effective dose in a logarithmic manner (all R-2 >= 0.97). For imaging of the lung region, a low voltage (60 kVp) produced the highest CNR, whereas a high voltage (125 kVp) produced the highest TRR. In the heart/spine region, 80125 kVp produced the highest CNR, while in the diaphragm region 60-90 kVp produced the highest CNR. For chest radiography with this CR system, the optimal tube voltage depends upon the region of interest. Of the filters tested, a 0.1 mm Cu thickness was found to provide a statistically significant increase in the CNR in the diaphragm region with tube potentials of 60 kVp and 80 kVp, without affecting the CNR in the other anatomical compartments.
In 2009, the German radar satellite TerraSAR-X will be supplemented with its twin;the TanDEM-X satellite. Together, they will fulfil the primary TanDEM-X mission goal of deriving a global Digital Elevation Model (DEM)...
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ISBN:
(纸本)9783800730841
In 2009, the German radar satellite TerraSAR-X will be supplemented with its twin;the TanDEM-X satellite. Together, they will fulfil the primary TanDEM-X mission goal of deriving a global Digital Elevation Model (DEM) with an unprecedented accuracy corresponding to HRTI-3 specifications (2 m relative point-to-point height accuracy for moderate terrain at 12 m posting). First interferometric processing results from TerraSAR-X repeat-pass acquisitions impressively demonstrate the DEM accuracy that can be achieved from such high resolution X band data. They also confirm the suitability of the phase preserving focussing algorithms, the successful migration of the InSAR algorithms from SRTM to the new challenging TerraSAR-X domain (requiring e.g. terrain dependent co-registration) and the stability of the instrument. This paper outlines the planned SAR data workflow from screening over bistatic focussing and interferometric processing to raw DEM generation. It addresses some aspects of the SAR processing algorithm which exploits the synergies of bistatic focussing and interferometric processing parameter calculation. Intermediate complex image products are introduced. Emphasis is laid on required co-registration accuracy and multi-baseline phase unwrapping and DEM reconstruction algorithms foreseen for the TanDEM-X data processing.
In this paper, we propose new query processing algorithms for typical spatial queries in SNDB, such as range search and k nearest neighbors (k-NN) search. Our two query processing algorithms can reduce the computation...
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ISBN:
(纸本)9780769530451
In this paper, we propose new query processing algorithms for typical spatial queries in SNDB, such as range search and k nearest neighbors (k-NN) search. Our two query processing algorithms can reduce the computation time of network distance between a pair of nodes and the number of disk I/Os required for accessing nodes by using a materialization-based technique with the shortest network distances of all the nodes in the spatial network. Thus, our query processing algorithms improve the existing efficient k-NN (INE) and range search (RNE) algorithms proposed by [1]. It is shown that our range query processing algorithm achieves about up to one of magnitude better performance than the RNE and our k-NN query processing algorithm achieves about up to 150% performance improvements over INE.
The Microwave Observatory of Subcanopy and Subsurface (MOSS) is a conceptual mission addressing observations of soil moisture in the root zone and under substantial vegetation canopies [1]. As penetration depth throug...
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ISBN:
(纸本)9781424420414
The Microwave Observatory of Subcanopy and Subsurface (MOSS) is a conceptual mission addressing observations of soil moisture in the root zone and under substantial vegetation canopies [1]. As penetration depth through vegetation and ground is paramount in meeting the objectives of this mission, there is a need for using lower frequencies. In particular, the instrument proposed for this mission is a dual-band synthetic aperture radar (SAR) operating at VHF and UHF bands. To meet the 7-10 day temporal coverage requirement for this mission, a large (340-430 km) swath is required. To meet the additional requirement that the incidence angle be small and vary moderately over the swath implies that the platform altitude must be large enough so that a relatively small range beam-width fully covers the entire swath. To achieve the beam-widths resulting from these requirements, the width of the VHF aperture must be 11 m, while the width of the UHF aperture must be 3 m. The length of the antenna for both frequencies must be 30m. These simultaneous requirements dictate a mechanical implementation, which can only be practically deployed in space if the antenna aperture is shared by both of the frequencies. Among various potential concepts, application of a center-fed parabolic reflector antenna fed by a linear array feed is the most promising one [2]. The technology of the mesh reflector antennas with dimensions of up to 25-30m is developing steadily, as evidenced by the demonstrated Thuraya antenna [3]. Parametric studies on this 12-m antenna design have proven the same design to be scalable to 30m. The key challenge in our design lies in achieving the highly elliptical (30m×3m UHF, and 30m×11m VHF) illumination ratios required to form the SAR aperture using a center-fed reflector antenna. The achievable cross-pol isolation needs to be considered in the mission and processing algorithm design. Our "shared-aperture" design entails the illuminate of a 30-m reflector antenna such
The article features the award-wining framework, CLAM, for audio and music application development. CLAM stands for C++ Library for Audio and Music, it is an open source software framework processing audio and music, ...
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The article features the award-wining framework, CLAM, for audio and music application development. CLAM stands for C++ Library for Audio and Music, it is an open source software framework processing audio and music, and a full-pledge software framework. Its framework offers several stand-alone applications including Salto, a real-time brass-instrument synthesizer, and Network Editor which is a visual-building tool. On the other hand, CLAM is not the only open source environment for audio and music there are also other environments that focuse on a particular aspect of the audio domain and how to present it to the user. It acknowledges that CLAM is a team effort that throughout the years has included around 20 different contributors.
The development of effective control architectures for Intervention AUVs (I-AUV) is a very challenging task due to the inherent complexities of the environment and the necessity of the vehicle to come into contact wit...
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ISBN:
(纸本)9781424406340;142440634X
The development of effective control architectures for Intervention AUVs (I-AUV) is a very challenging task due to the inherent complexities of the environment and the necessity of the vehicle to come into contact with underwater structures without closed-loop supervision. Despite this, both the scientific and industrial communities are keen supporters of the development of I-AUV technology owing to the relevant cost saying opportunities they are potentially able to offer in a number of applications. In this article we describe a comprehensive control architecture designed to dock an I-AUV on a receiving structure, using sonar and video image processing alongside navigation data from conventional sensors. The approach is based on custom developed sonar and video processing algorithms and the results are validated in real-time conditions by means of Ifremer's experimental underwater vehicle VORTEX.
An engineered artificial lateral-line system has been recently developed, consisting of a 16-element array of finely spaced MEMS hot-wire flow sensors. This represents a new class of underwater flow sensing instrument...
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An engineered artificial lateral-line system has been recently developed, consisting of a 16-element array of finely spaced MEMS hot-wire flow sensors. This represents a new class of underwater flow sensing instruments and necessitates the development of rapid, efficient, and robust signal processing algorithms. In this paper, we report on the development and implementation of a set of algorithms that assist in the localization and tracking of vibrational dipole sources underwater. Using these algorithms, accurate tracking of the trajectory of a moving dipole source has been demonstrated successfully. Copyright (C) 2006 Saunvit Pandya et al.
algorithms for processing signals in electrothermal atomic-absorption spectrometry are considered on the basis of mathematical simulation. A new processing algorithm based on interpolation of absorption signals by mea...
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algorithms for processing signals in electrothermal atomic-absorption spectrometry are considered on the basis of mathematical simulation. A new processing algorithm based on interpolation of absorption signals by means of the Arrhenius' equation is developed. The optimality of the new algorithm is confirmed by means of physical measurements.
WAVEWAT is a new processing algorithm to suppress the on-resonance water signal in NMR spectra. It is based on a multiresolution analysis (MRA) of the free induction decay (FID) using a dyadic discrete wavelet transfo...
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WAVEWAT is a new processing algorithm to suppress the on-resonance water signal in NMR spectra. It is based on a multiresolution analysis (MRA) of the free induction decay (FID) using a dyadic discrete wavelet transform (DWT). The width of the suppressed signal can be adjusted so that signals close to water are recovered without distortion of the signal shape and intensity. Computational efficiency is comparable to that of convolution filters employing a Fourier transform. (C) 2002 ELsevier Science (USA).
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