17,275 research outputs found
Optimizing Service Differentiation Scheme with Sized-based Queue Management in DiffServ Networks
In this paper we introduced Modified Sized-based Queue Management as a
dropping scheme that aims to fairly prioritize and allocate more service to
VoIP traffic over bulk data like FTP as the former one usually has small packet
size with less impact to the network congestion. In the same time, we want to
guarantee that this prioritization is fair enough for both traffic types. On
the other hand we study the total link delay over the congestive link with the
attempt to alleviate this congestion as much as possible at the by function of
early congestion notification. Our M-SQM scheme has been evaluated with NS2
experiments to measure the packets received from both and total link-delay for
different traffic. The performance evaluation results of M-SQM have been
validated and graphically compared with the performance of other three legacy
AQMs (RED, RIO, and PI). It is depicted that our M-SQM outperformed these AQMs
in providing QoS level of service differentiation.Comment: 10 pages, 9 figures, 1 table, Submitted to Journal of
Telecommunication
Design of time delayed chaotic circuit with threshold controller
A novel time delayed chaotic oscillator exhibiting mono- and double scroll
complex chaotic attractors is designed. This circuit consists of only a few
operational amplifiers and diodes and employs a threshold controller for
flexibility. It efficiently implements a piecewise linear function. The control
of piecewise linear function facilitates controlling the shape of the
attractors. This is demonstrated by constructing the phase portraits of the
attractors through numerical simulations and hardware experiments. Based on
these studies, we find that this circuit can produce multi-scroll chaotic
attractors by just introducing more number of threshold values.Comment: 21 pages, 12 figures; Submitted to IJB
Preparation of proton exchange membrane by radiation-induced grafting method : Grafting of styrene onto poly(ethylene tetrafluoroethylene) copolymer films
Radiation induced grafting of styrene onto poly(ethylene-tetrafluoroethylene) (ETFE) copolymer film was carried out to prepare graft copolymer (ETFE-g-polystyrene) that can host sulfonic acid groups and form proton exchange membrane for polymer electrolyte fuel cell (PEFC). The effect of monomer concentration and type of solvent on the degree of grafting was investigated. The formation of graft copolymer film was confirmed by FTIR spectrum analysis
Modelling the Impact of Credit on Intensification in Mixed Crop-Livestock Systems: A Case Study from Ethiopia
Access to credit is one strategy for promoting the adoption of yield-enhancing technologies. However, advancing credit to smallholder farmers for encouraging technology adoption is a complex policy issue. The objective of this paper is to identify appropriate and sustainable credit repayment policies to encourage intensification in the Ethiopian Highlands. Using a household model, we analyze the impact of advancing in-kind credit in the form of fertilizer and seed to smallholder farmers in the Ethiopian highlands and alternative credit repayment strategies. The results indicate that in kind input credit of fertilizer and seed provided to farmers in the highland of Ethiopia increased the value of household crop output moderately and hence allowed the household to increase its consumption. This scheme requires borrowers to sell their crop immediately at harvest to repay their credit. An alternative repayment scheme of extending the repayment period to allow households to capture seasonal price variation is proposed. The amount repaid is also tied to yields of wheat.Agricultural Finance,
Evaluation of Water Resources in Wadi El Natrun, Western Desert, Egypt
Groundwater of the Pliocene aquifer in Wadi El Natrun area represents the primary source of reliable water for drinking and agriculture uses. This research focuses on the study of the different sources of water in the study area and determines the origin and quality of this waterand also is interested in studying hydrogeochemical processes that affect them and the movement of water through the analysis and determine the activity of different elements, and also to changes in hypothetical salts with the direction of water flow in three sectors of the region and the statement of the most important geochemical processes that occur. Finally it is evaluated the suitability of the water for different purposes.
The results show that, there is a zonation of chemical composition; this zonation is characterized by a change of cation species from dominantly Ca and Mg near the east to Na-dominated waters in the west. Mirroring this, anions change from HCO3 type to Cl and SO4 type.The ions displays two grades of metasomatism along flow path, first the stage of mineralization(HCO3>Cl>So4) at the east then the advanced stage of mineralization (Cl>SO4 >HCO3) at the west. According to the(W.H.O.2005), 45 % of tested groundwater samples are permissible for drinking. Most groundwater samples of the Pliocene according to SAR andRSC are suitable for irrigation purposes under normal condition, but all surface water samples (lakes) are saline water,so it is not valid for drinking or irrigation purposes
A finite volume method for scalar conservation laws with stochastic time-space dependent flux function
We propose a new finite volume method for scalar conservation laws with stochastic time–space dependent flux functions. The stochastic effects appear in the flux function and can be interpreted as a random manner to localize the discontinuity in the time–space dependent flux function. The location of the interface between the fluxes can be obtained by solving a system of stochastic differential equations for the velocity fluctuation and displacement variable. In this paper we develop a modified Rusanov method for the reconstruction of numerical fluxes in the finite volume discretization. To solve the system of stochastic differential equations for the interface we apply a second-order Runge–Kutta scheme. Numerical results are presented for stochastic problems in traffic flow and two-phase flow applications. It is found that the proposed finite volume method offers a robust and accurate approach for solving scalar conservation laws with stochastic time–space dependent flux functions
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