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A parallel version of quicksort on a CRCW PRAM is developed. The algorithm uses n processors and a linear space to sort n keys in the expected time O(log n) with large probability. 相似文献
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aneta Polkowska Jacek Namienik Jacek Czerwiski & Bogdan Zygmunt 《International Journal of Food Science & Technology》1996,31(5):387-395
Applicability of thin-layer headspace (TLHS) procedure giving an aqueous concentrate and also classical purge and trap (PT) in off-line mode to isolate and enrich volatile organohalogen compounds in common beverages was tested. Both enrichment tech-niques were used in combination with gas chromatography – electron capture detection (GC-ECD). TLHS, combined with direct aqueous injection (DAI)-GC-ECD, proved applicable in the determination of volatile organohalogen compounds in all studied beverages, while the PT in a version with no preliminary sample pre-treatment was of limited applicability. Detection limits of the TLHS-based procedure were in the order of 1 ppt. Content of volatile organohalogen compounds in a number of beverages available on the Polish market including mineral waters, beers, juices, carbonated and non-carbonated soft drinks, etc. was determined by means of TLHS-DAI-GC-ECD. 相似文献
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The various complex mathematical transformations previously proposed for eliminating methodological errors of multicolor radiation pyrometry are mainly reduced to the determination of such combinations of wavelengths or corrections of registered brightness for the spectral distribution of the radiating capacity of the object being thermometered at which its equivalent radiating capacity is equal to unity. Mathematical formulas of the determining parameters of multicolor pyrometry of radiation have been obtained. Engineering techniques for calculating the critical values of the determining and adjustable parameters at which the application of multicolor optical thermometry is excluded because of large errors have been developed. Algorithms of a priori and a posteriori calibration systems of multicolor pyrometry of radiation of objects with practically any spectral distribution of the radiating capacity are proposed. 相似文献
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This study is focused on structural modifications of leptomeninges and cerebral matter in children deceased because of iatrogenic AIDS. Although we do not evidence the specific lesions of AIDS, we have noticed edema, hyperemia, hematic extravasation, microlesions of the small vessel walls, perivascular infiltrations with lymphocytes, macrophages and even plasmocytes, moderate tigrolysis, mild demyelination, gliosis and sidero-calcic deposits. We do not consider these lesions as specific to HIV-infected patients. 相似文献
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Sinuo Liu Xiaokun Wang Xiaojuan Ban Yanrui Xu Jing Zhou Jií Kosinka Alexandru C. Telea 《Computer Graphics Forum》2021,40(1):54-67
A major issue in smoothed particle hydrodynamics (SPH) approaches is the numerical dissipation during the projection process, especially under coarse discretizations. High‐frequency details, such as turbulence and vortices, are smoothed out, leading to unrealistic results. To address this issue, we introduce a vorticity refinement (VR) solver for SPH fluids with negligible computational overhead. In this method, the numerical dissipation of the vorticity field is recovered by the difference between the theoretical and the actual vorticity, so as to enhance turbulence details. Instead of solving the Biot‐Savart integrals, a stream function, which is easier and more efficient to solve, is used to relate the vorticity field to the velocity field. We obtain turbulence effects of different intensity levels by changing an adjustable parameter. Since the vorticity field is enhanced according to the curl field, our method can not only amplify existing vortices, but also capture additional turbulence. Our VR solver is straightforward to implement and can be easily integrated into existing SPH methods. 相似文献
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Popa Iolanda V. Burlacu Alexandru Gavrilescu Otilia Dranga Mihaela Prelipcean Cristina Cijevschi Mihai Cătălina 《Neural computing & applications》2021,33(21):14133-14146
Neural Computing and Applications - Colonoscopy is the “gold” standard for evaluating disease activity in ulcerative colitis (UC). An important area of research is finding a... 相似文献
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This paper proposes a system for the early automatic recognition of health problems that manifest themselves in distinctive
form of gait. Purpose of the system is to prolong the autonomous living of the elderly at home. When the system identifies
a health problem, it automatically notifies a physician and provides an explanation of the automatic diagnosis. The gait of
the elderly user is captured using a motion-capture system, which consists of body-worn tags and wall-mounted sensors. The
positions of the tags are acquired by the sensors and the resulting time series of position coordinates are analyzed with
machine-learning algorithms in order to recognize a specific health problem. Novel semantic features based on medical knowledge
for training a machine-learning classifier are proposed in this paper. The classifier classifies the user’s gait into: 1)
normal, 2) with hemiplegia, 3) with Parkinson’s disease, 4) with pain in the back and 5) with pain in the leg. The studies
of 1) the feasibility of automatic recognition and 2) the impact of tag placement and noise level on the accuracy of the recognition
of health problems are presented. The experimental results of the first study (12 tags, no noise) showed that the k-nearest
neighbors and neural network algorithms achieved classification accuracies of 100%. The experimental results of the second
study showed that classification accuracy of over 99% is achievable using several machine-learning algorithms and 8 or more
tags with up to 15 mm standard deviation of noise. The results show that the proposed approach achieves high classification
accuracy and can be used as a guide for further studies in the increasingly important area of Ambient Assisted Living. Since
the system uses semantic features and an artificial-intelligence approach to interpret the health state, provides a natural
explanation of the hypothesis and is embedded in the domestic environment of the elderly person; it is an example of the semantic
ambient media for Ambient Assisted Living. 相似文献