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Atm Switch Architecture and Systems
Published in Naoaki Yamanaka, High-Performance Backbone Network Technology, 2020
Since the link groups follow the interconnection pattern of a delta network with 2 × 2 modules, this network can inherently support the self-routing feature based on the destination output port address. Unicast cells utilize the self-routing feature according to their destination output port addresses. The first s bits of the destination address are used as a routing tag at the distribution network; the k-th bit in the routing tag determines the outgoing link group of the k-th stage, i.e., “0” for upper link group and “1” for lower link group. The remaining log2n bit address is utilized in the routing at the OSM.
Convergent Network Management and Control Plane
Published in Iannone Eugenio, Telecommunication Networks, 2017
The structure of this bigger record is reported in Table 8.1. Two links attributes of Table 8.1 are worth a comment. The first is the last attribute of the record, advertising that the link is part of a shared risk link group (SRLG). An SRLG is a group of links that will fail contemporary when a certain type of failure happens.
Guaranteed Application Experience
Published in Cheng Sheng, Jie Bai, Qi Sun, Software-Defined Wide Area Network Architectures and Technologies, 2021
A traffic steering policy defines the following items: Requirements of applications on the link qualitySpecify the packet loss rate, latency, and jitter thresholds. When a threshold is reached, a link switchover is triggered.Link groupSpecify the available links in normal situations and escape links. If a link in the primary link group is available, links in the secondary link group will not be used.Links in a link groupSpecify the links in a link group and their priorities. Links can have the same or different priorities. If links have the same priority, traffic is load balanced between them.Whether to perform load balancingIf load balancing is configured, a load balancing algorithm based on the weights of same-priority link bandwidths is used to load balance traffic between the links. This algorithm enables links with higher bandwidth to take more traffic.Application priorityDifferent types of traffic can be steered based on their priorities. If congestion occurs, the traffic of low-priority applications will be migrated to other links to guarantee the experience of high-priority applications.
Solubility of water in mixtures of (n-alkanes + n-perfluoroalkanes) and in n-perfluoroalkylalkanes: experiments and modelling with the SAFT-γ Mie group-contribution approach
Published in Molecular Physics, 2021
Pedro Morgado, João Barras, Amparo Galindo, George Jackson, Eduardo J. M. Filipe
The underestimation of the water solubility in the PFAAs strongly suggests that these systems exhibit a specific interaction between water and the link group (CH2CF2), which needs to be accounted for in addition to the other unlike interactions. As discussed in a previous work [29], this specific interaction is associated with Keesom forces between the permanent dipole of water and the localised dipole at the alkyl – perfluoroalkyl junction. In our work, we model this specific interaction by estimating the unlike interaction energy parameter (ϵkl) between water and the CH2CF2 group to reproduce the experimental solubility of water in PFAAs. The solubilities obtained with the SAFT-γ Mie group-contribution approach using the optimised H2O – CH2CF2 unlike interaction are also shown in Figure 4, where it can be seen that good agreement with the experimental data is achieved. The theory now correctly reproduces the magnitude and temperature dependence of the experimental values, as well as the order of relative solubility for the various systems. The value estimated for the unlike interaction energy parameter ( = 613.48 K) is quite large when compared to the unlike interaction energy parameters for the alkyl ( = 235.67 K; = 327.22 K) and perfluoroalkyl ( = 212.07 K; = 315.60 K) groups. This is further evidence, obtained independently through the theoretical SAFT-γ Mie description, of the relevance of the significant interaction between water and the dipole at the alkyl-perfluoroalkyl bond. By analyzing the water-rich phase it is apparent that the solubility of PFAAs in water is predicted to be significantly higher than that of n-alkanes (cf. Figure 1) or n-perfluoroalkanes (cf. Figure 2) of the same chain length, indicative the influence of these polar interactions also in the behaviour of the aqueous phase; unfortunately, no experimental results are yet available to assess these predictions.
Comparison of three related imidazolium ionic liquids and their CS2 solutions
Published in Molecular Physics, 2020
A clearer difference in the behaviour of the three liquids is found from the limiting slopes of the mean square displacements of sites in individual ions as a function of time t which are related to diffusion constants D by where is the mean square displacement of sites in the species under consideration and is a constant with dimensions of length squared. This can be correlated with the square of the size of the cage which the molecule or ion has to escape from before becoming free. In fact it has been shown that the mean square displacements in ionic liquid solutions do not always reach this asymptotic behaviour for times of the order of nanoseconds [3,34], but reproducible linear behaviour of the form of this equation is found for times of the order of hundreds of picoseconds and can be used to define effective diffusion constants. The sites chosen were the C site on imidazolium rings, the N site on the anion and the C site on CS, rather than the cation and anion centres of mass. This avoids including any motion of the flexible alkyl groups. Figure 7 shows effective diffusion constants of each of the three sites in the three solutions determined from the mean square displacements between 80 and 200 ps. Not surprisingly, in any given solution CS, being smaller and uncharged, diffuses fastest. One also finds that the imidazolium moieties diffuse faster than the smaller [NTf anions even in the dication solution showing that the motion of the anions and charged imidazolium rings are strongly correlated. Diffusion of any one species in different solutions is similar in the two monocationic solutions and much slower in the dication solution. It seems that the tying together of two charged imidazolium ions by an alkyl chain constrains both their motion and the motion of other species in the solution significantly compared with that in liquids with single imidazolium rings. This is true even if the alkyl tail is as long as the link group in the dication. Experimentally a similar effect is seen in the viscosities which are much greater in dication solutions than in in the corresponding monocationic solutions. For example the viscosity of [Cim][NTf] [35] is 31 mPa.s at 318 K (20C) while that of [C(im)[NTf] is 900 mPa.s at the same temperature [36].