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171.
172.
Nasser‐Eddine Rikli 《International Journal of Communication Systems》2007,20(4):461-475
DiffServ architecture has been widely adopted for the provision of QoS over the Internet. This makes the full understanding of its operation imperative. We believe that only mathematical analysis may have the power of such goal. As the heart of a DiffServ router is the token bucket algorithm, a generic one, with two‐colours marking, is to be considered here. A mathematical framework will be first developed for its analysis. Then, assuming an input traffic with Poisson arrivals and Exponential packet lengths, and a memoryless token bucket system, the two types of generated streams will be statistically characterized through their distributions and averages. This analysis will be carried out for two types of buckets, one with infinite size and a second with finite size. It will be shown how the derived equations will allow the prediction of the output traffic streams for given bucket and input traffic stream parameters. The paper will be then complemented by conclusions and suggestions. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
173.
A. M. Issam M. Haris 《Journal of Inorganic and Organometallic Polymers and Materials》2009,19(4):454-458
A new nonlinear polysilylether containing azomethine group was synthesized from 3,4-di-(2′-hydroxyethoxy)-4′-nitrobenzylidene
with dichlorodiphenylsilane in the presence of anhydrous pyridine. The chemical structure of the polysilylether was characterized
by C–H–N analysis and FT-IR, 1H-NMR, 29Si-NMR, and UV-Vis spectroscopy. The nonlinear optical property of the new polysilylether has been studied via the second
harmonic generation (SHG) and the values of electro-optic coefficients d33 and d31 of the poled polysilylether film were 7.88 × 10−5 and 5.70 × 10−5 esu, respectively. The thermal behavior of the polysilylether was studied by thermogravimetric analysis (TGA) and differential
scanning calorimetry (DSC). 相似文献
174.
Issam Doghri 《International journal for numerical methods in engineering》1993,36(22):3915-3932
This paper deals with the numerical integration of a class of rate-independent elasto-plastic models. The backward Euler scheme is used to integrate the rate constitutive relations. The non-linear equations obtained are solved by the Newton method. The consistent tangent modulus is obtained by exact linearization of the algorithm. In the case of J2 elasto-plasticity with non-linear isotropic hardening and non-linear kinematic hardening (Chaboche-Marquis model), explicit formulas are derived, without any approximations. 相似文献
175.
A semi-numerical method is presented for the analysis of orthotropic rectangular plates subjected to uniform, linearly-varying and partial inplane loads. The solution procedure is based on the classical method of separation of variables. The basic functions are chosen as the eigenfunctions for straight prismatic beams in free vibration. The two-dimensional governing partial differential equation is first reduced to an ordinary differential equation. The classical unidirectional finite difference method is then employed to solve the resulting ordinary differential equation. Results are presented for plates with different edge and loading conditions. 相似文献
176.
Issam Dagher 《Signal, Image and Video Processing》2010,4(3):303-307
In this paper highly-compacted DCT coefficients (HDCT) are presented. This compactness is achieved by sorting in ascending
order the data first, then by applying the Discrete Cosine transform (DCT) to the ordered data. Images are highly correlated.
DCT exhibits excellent energy compaction. It will be shown that HDCT has much better energy compactness than the DCT. This
has the effect of representing every ordered image with very small number of HDCT coefficients (dimensionality reduction).
The compression capabilities of the HDCT are presented. HDCT is also applied to face recognition problem. Simulation results
on different databases showed high average success rate of this algorithm compared to other algorithms. 相似文献
177.
Baolin Zhao Gaohong He Issam El Hamouti Li Gao Yanjun Liu Runlian Deng Xiaoming Yan 《International Journal of Hydrogen Energy》2017,42(15):10228-10237
A novel strategy was proposed to construct a bicontinuous hydrophilic/hydrophobic micro-phase separation structure which is crucial for high hydroxide conductivity and good dimensional stability anion exchange membranes (AEMs). A semi-flexible poly (aryl ether sulfone) containing a flexible aliphatic chain in the polymer backbone with imidazolium cationic group was synthesized by the polycondensation of bis(4-fluorophenyl) sulfone and the self-synthesized 4,4′-[butane-1,4-diylbis(oxy)] diphenol followed by a two-step functionalization. The corresponding membranes were prepared by solution casting. More continuous hydroxide conducting channels were formed in the semi-flexible polymer membranes compared with the rigid based ones as demonstrated by TEM. As a result, given the same swelling ratio, hydroxide conductivity of the semi-flexible polymer membrane was about 2-fold higher than the one of the rigid polymer based membrane (e.g., 45 vs. 22 mS cm?1 with the same swelling ratio of 24% at 20 °C). The highest achieved conductivity for the semi-flexible polymer membranes at 60 °C was 93 mS cm?1, which was much higher those of other random poly (aryl ether sulfone) based imidazolium AEMs (27–81 mS cm?1). The single cell employing the semi-flexible polymer membrane exhibited a maximum power density of 125 mW cm?2 which was also higher than those for other random poly (aryl ether sulfone) based imidazolium AEMs (16–105.2 mW cm?2). 相似文献
178.
Jonathan Cimino David Calligaris Johann Far Delphine Debois Silvia Blacher Nor Eddine Sounni Agnès Noel Edwin De Pauw 《International journal of molecular sciences》2013,14(12):24560-24580
Many studies have evidenced the main role of lipids in physiological and also pathological processes such as cancer, diabetes or neurodegenerative diseases. The identification and the in situ localization of specific low-abundant lipid species involved in cancer biology are still challenging for both fundamental studies and lipid marker discovery. In this paper, we report the identification and the localization of specific isobaric minor phospholipids in human breast cancer xenografts by FTICR MALDI imaging supported by histochemistry. These potential candidates can be further confirmed by liquid chromatography coupled with electrospray mass spectrometry (LC-ESI-MS) after extraction from the region of interest defined by MALDI imaging. Finally, this study highlights the importance of characterizing the heterogeneous distribution of low-abundant lipid species, relevant in complex histological samples for biological purposes. 相似文献
179.
A.-M. Layre P. Couvreur J. Richard D. Requier N. Eddine Ghermani R. Gref 《Drug development and industrial pharmacy》2013,39(7):839-846
ABSTRACTThe effects of four sugars (glucose, saccharose, maltose, trehalose) and one surfactant (Poloxamer 188), on the freeze-drying of poly(isobutylcyanoacrylate) (PIBCA), poly(ε-caprolactone)-poly(ethylene glycol) (PCL-PEG), and novel core (mainly PIBCA)-shell (principally PEG) composite nanoparticles (CNP) obtained by co-precipitation were investigated. The efficiency of the additives against the adverse effect of freeze-drying on the redispersibility of the nanoparticles was evaluated, based on the visual appearance of the nanoparticle suspensions (Tyndall effect and aggregation), and on the determination of the mean diameter ratio of the nanoparticles before and after freeze-drying. The results indicated that the addition of both sugars and surfactant was essential for the good redispersion of freeze-dried nanoparticles displaying hydrophobic (PIBCA) or hydrophilic (PCL-PEG and CNP) surfaces. 相似文献
180.
Issam Salhi Saïd Doubabi Najib Essounbouli Abdelaziz Hamzaoui 《Renewable Energy》2010,35(9):2071-2079
Modelling hydraulic turbine generating systems is not an easy task because they are non-linear and uncertain where the operating points are time varying. One way to overcome this problem is to use Takagi–Sugeno (TS) models, which offer the possibility to apply some tools from linear control theory, whereas those models are composed of linear models connected by a fuzzy activation function. This paper presents an approach to model and control a micro hydro power plant considered as a non-linear system using TS fuzzy systems. A TS fuzzy system with local models is used to obtain a global model of the studied plant. Then, to combine efficiency and simplicity of design, PI controllers are synthesised for each considered operating point to be used as conclusion of an electrical load TS Fuzzy controller. The latter ensures the global stability and desired performance despite the change of operating point. The proposed approach (model and controller) is tested on a laboratory prototype, where the obtained results show their efficiency and their capability to ensure good performance despite the non-linear nature of the plant. 相似文献