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151.
This work describes a computational approach for a typical machine-vision application, that of human action recognition from video streams. We present a method that has the following advantages: (a) no human intervention in pre-processing stages, (b) a reduced feature set, (c) modularity of the recognition system and (d) control of the model’s complexity in acceptable for real-time operation levels. Representation of each video frame and feature extraction procedure are formulated in the lattice theory context. The recognition system consists of two components: an ensemble of neural network predictors which correspond to the training video sequences and one classifier, based on the PREMONN approach, capable of deciding at each time instant which known video source has potentially generated a new sequence of frames. Extensive experimental study on three well known benchmarks validates the flexibility and robustness of the proposed approach. 相似文献
152.
As the heterogeneity of Internet traffic increases, the need to provide the necessary quality guarantees for a broad range of applications becomes more and more important. We propose an Active Queue Management scheme, namely Size-oriented Queue Management, which realizes service differentiation based on the Less Impact–Better Service principle. SQM manages to satisfy broadly the quality constraints of real-time applications, without compromising the performance of bulk data applications. Using packet size as criterion, we are able to distinguish time-sensitive flows and apply different dropping and scheduling policies to favor time-sensitive traffic. Our simulation results indicate that SQM manages to increase application satisfaction and augment the user-perceived quality. 相似文献
153.
Ageliki Tsioliaridou Author Vitae Vassilis Tsaoussidis Author Vitae 《Journal of Systems and Software》2010,83(5):745-762
Most AQM algorithms, such as RED, assure fairness through randomness in congestion notification. However, randomness results in fair allocation of network resources only when time limitations are not considered. This is not compatible with the current Internet, where traffic oscillations are frequent and the demand for fair treatment is rather urgent, due to short duration of most applications. Given the short duration of most modern Internet applications, fast convergence to fairness is necessitated. In this paper, we use fairness as the major criterion to adjust traffic and present a corresponding algorithm of active queue management, which is called Explicit Global Congestion Notifier (EGCN). EGCN notifies flows almost simultaneously about incipient congestion by marking packets arriving at the router’s queue, when the load in the network increases and buffer overflow is expected. This is a new approach compared with the random notification policy of RED or ECN. EGCN distributes the burden to adjust backward to more flows and consequently allows for smoother window adjustments. We elaborate on the properties of system-wide response in terms of fairness, smoothness and efficiency. Simulation results demonstrate a clear-cut advantage of the proposed scheme. 相似文献
154.
Efstathios Anastasopoulos Nick Kalogeropoulos Andriana C. Kaliora Ageliki Falirea Vassilis N. Kamvissis Nikolaos K. Andrikopoulos 《Journal of the American Oil Chemists' Society》2012,89(2):253-259
The quality characteristics and bioactive microconstituents of virgin olive oil produced by Mavrolia cv, an Olea europaea variety grown in Southern Peloponnesus, Greece, are reported for the first time. The oil samples of Mavrolia cv. studied
fell within the limits established for the extra virgin olive oil (EVOO) category and were characterized by higher levels
of campesterol (88.7 ± 14.8 vs. 56.1 ± 6.1 mg kg−1 oil) and β-sitosterol (1692.6 ± 100.3 vs. 1356.2 ± 85 mg kg−1 oil) and relatively lower oxidative stability (19.35 ± 2.62 vs. 37.44 ± 1.97 h) compared to Koroneiki cv. The lower oxidative
stability was positively correlated to significantly lower polyphenols (88.95 ± 2.33 vs. 233.75 ± 34.29) and α-tocopherol
(517.2 ± 6.50 vs. 655.37 ± 17.78) and to higher polyunsaturated fatty acids content (9.27 ± 0.35 vs. 6.41 ± 0.38). Tyrosol,
ferulic acid and protocatechuic acid contents were significantly higher in Mavrolia cv. samples compared to Koroneiki cv.
(218.80 ± 44.8 vs. 83.7 ± 23.1, 1.82 ± 0.11 vs. 0.97 ± 0.31, and 1.55 ± 0.39 vs. 0.35 ± 0.60 mg kg−1, respectively). Also, the bitter and pungent attributes were found in lower intensities compared to Koroneiki cv. EVOO for
the same period (1.9 vs. 2.5 and 2.3 vs. 3.9, respectively). The ripe fruity intensity with walnut olfactory attribute of
the Mavrolia cv., was also light to medium. 相似文献
155.
The purpose of this study was to evaluate the effect of prolonged heat processing (180 min at 50-80 °C) on the functional and rheological properties of pectin, derived from olive mill wastewater (OMW). It was shown that a low temperature blanching of OMW at 60 °C, activates endogenous pectin methyl esterase and promotes demethylation, despite the high concentration of phenols. Activation of the enzyme resulted in enhanced solubilization and subsequent partial degradation of pectin. The induced degradation impaired pectin grade and resulted in loss of gelling functionality. An alternative heating process at 80 °C resulted in negligible enzyme induced degradation of the pectin and improved gelling properties of the recovered material, despite the lower solubilization of the pectin. The obtained results contribute to a better understanding of the temperature effect on pectin functional properties and can be utilized in order to optimize pectin recovery from OMW. 相似文献
156.
The objective of the current study is to investigate the clarification of two high-added value products (pectin containing solution and phenol containing beverage) recovered from olive mill wastewater. For this purpose, both liquids were processed with four types of ultrafiltration (100, 25, 10 and 2 kDa) and one nanofiltration membranes under optimum transmembrane pressure. Retention coefficients and performance parameters were monitored for each experiment. The membranes of 25 and 100 kDa showed very satisfying results with regard to the concentration of pectin solutions as they were able to separate it from cations and phenols. The membrane of 25 kDa was also able to partially remove the heavier fragments of hydroxycinnamic acid derivatives and flavonols, and simultaneously to sustain the antioxidant properties of the phenol containing beverage in the permeate stream. Finally, nanofiltration clarified the beverage from cations that passed in the permeate stream, but this process resulted in loss of antioxidant compounds, too. 相似文献
157.
Nicos Maglaveras Ioanna Chouvarda Vassilis G Koutkias George Gogou Irini Lekka Dimitrios Goulis Avram Avramidis Charalambos Karvounis George Louridas E Andrew Balas 《IEEE transactions on information technology in biomedicine》2005,9(3):353-362
In the context of the Citizen Health System (CHS) project, a modular Medical Contact Center (MCC) was developed, which can be used in the monitoring, treatment, and management of chronically ill patients at home, such as diabetic or congestive heart failure patients. The virtue of the CHS contact center is that, using any type of communication and telematics technology, it is able to provide timely and preventive prompting to the patients, thus, achieving better disease management. In this paper, we present the structure of the CHS system, describing the modules that enable its flexible and extensible architecture. It is shown, through specific examples, how quality of healthcare delivery can be increased by using such a system. 相似文献
158.
EDM electrode manufacture using rapid tooling: a review 总被引:1,自引:0,他引:1
John Kechagias Vassilis Iakovakis Manolis Katsanos Stergios Maropoulos 《Journal of Materials Science》2008,43(8):2522-2535
Electrical discharge machining (EDM) is a non-conventional process for the manufacture of complex or hard material parts that
are difficult to machine by conventional machining processes. During EDM, the electrode shape is mirrored in the workpiece.
As a result, problems are transferred on the electrode manufacturing process. Rapid tooling (RT) is a new technology which
uses rapid prototyping (RP) models to reduce the time and cost of tool manufacture. The various methods of manufacturing RT
electrodes, with respect to different materials and the incorporated supplementary processes, are classified in the present
work. Recent international research work on RT electrodes is reviewed and the results on the performance of RT electrodes
are tabulated. 相似文献
159.
Theocharis C. Stamatatos Konstantina V. Pringouri Catherine P. Raptopoulou Ramon Vicente Vassilis Psycharis Albert Escuer Spyros P. Perlepes 《Inorganic chemistry communications》2006,9(12):1178-1182
The reaction of the oxide-centred triangular, trichromium(III,III,III) complex [Cr3O(O2CCMe3)6(H2O)3](O2CCMe3) with di-2-pyridyl ketone oxime, (py)2CNOH, in MeCN under aerobic and refluxing conditions yields the pivalate-free, dichromium(II,II) complex [Cr2{(py)2CNO}4] · 2H2O (1 · 2H2O). The dinuclear complex can also be prepared by the reaction of [Cr(CO)6] with (py)2CNOH in refluxing MeCN/H2O in air. The two high-spin CrII atoms are doubly bridged by two 2.1110 oximate ligands, while a chelating 1.0110 (py)2CNO− ion completes distorted trigonal bipyramidal coordination at each metal centre. The dimers are stabilized by intramolecular stacking interactions between the terminal (py)2CNO− ligands, and the structural effects of these interactions are discussed. 相似文献
160.
Saurabh Bahuguna Vassilis P. Panoskaltsis Katerina D. Papoulia 《Canadian Metallurgical Quarterly》2006,132(3):231-239
The accumulation of permanent deformations in asphalt concrete under repeated loading, a phenomenon of great practical importance, is studied in detail and a new multidimensional nonlinear hyperelastic-nonassociative plastic model is proposed. The equations of the model are solved by using the predictor–corrector algorithm. The model’s results are compared to actual experimental data and the comparison is very favorable. A remarkable result is that the model parameters obtained from one stress level predict correctly the results for another stress level. 相似文献