Comparison of IP micromobility protocols

We present a performance comparison of a number of key micromobility protocols that have been discussed in the IETF Mobile IP Working Group over the past several years. IP micromobility protocols complement Mobile IP by offering fast and seamless handoff control in limited geographical areas, and IP paging in support of scalability and power conservation. We show that despite the apparent differences between IP micromobility protocols, the operational principles that govern them are largely similar. We use this observation to establish a generic micromobility model to better understand design and performance trade offs. A number of key design choices are identified within the context of the generic model related to handoff quality and route control messaging. We present simulation results for Cellular IP, Hawaii, and Hierarchical Mobile IP, and evaluate the handoff performance of these protocols. Simulation results presented in this article are based on the Columbia IP Micromobility Software (CIMS), which is freely available from the Web (comet.columbia. edu/micromobility) for experimentation.     

The absorption of direct dyes by crosslinked cellulose. I. The equilibrium of dyeing

The effect of the degree of chemical crosslinking of cellulose with two bifunctional crosslinking agents dimethylol ethylene are (DMEU) and bis (hydroxyethyl) sulfur (BHES), on the equilibrium absorption of the direct dyes Chlorazol Sky Blue FF (C.I. Direct Blue 1) and Chrysophenine G (C.I. Direct Yellow 12) has been reported. The results show the increasing reduction of equilibrium dye absorption with increasing crosslink density. However, the maximum loss of absorption is about less than half of the amount absorbed by uncrosslinked cellulose. The results have been interpreted by reference to the parameters affecting the free energy of dyeing and the relevant models (pore model and gel model) available for explaining the fine structure of swollen cellulose.     

Voice QoS in third-generation mobile systems

We analyze voice quality and system performance in third-generation mobile communication systems. We argue that in these networks that are expected to integrate voice, data, and multimedia services, the transport network can no longer be considered as a lossless transparent traffic channel. Rather, proper dimensioning is needed even for plain voice services. Furthermore, the efficient utilization of the network resources shared by voice and data traffic requires sophisticated traffic management in the statistical multiplexing environment. The contribution of the paper is twofold: first, voice quality in the cellular transport network is analyzed and network dimensioning criteria are derived. Second, building on advances reported in the literature and taking into consideration current standardization activities, a joint performance model is established for the air interface (AI) and the transmission network (TN) allowing for the analysis of end-to-end service performance within a uniform framework. To demonstrate the applicability of this model, we point to some performance problems in the multiservice environment and suggest and evaluate traffic management actions to overcome these     

Radiance distribution on densely overcast skies: comparison with cie luminance standard

In this contribution some data measured in Europe are evaluated to enable the comparison of real radiance distributions with the CIE (International Commission on Illumination) luminance gradation approximation of the densely overcast sky. A question is posed whether such a model sky exists in reality, although the frequency of its occurrence might be different in different seasons and in regions with different climates. Eleven cases are evaluated in Figs. 1–3 with the comparison to the cosine and the exponential approximation curves. It seems that the measurement data agree with the CIE Standard but further tests and results obtained during the International Daylight Measurement Programme have to gather more evidence.     

Theoretical estimation of the effect of solvent on unperturbed dimensions: 1. Isotactic poly(vinyl alcohol)

The effect of the quality of solvent on the unperturbed chain dimensions $\text{r}{}_0{}^2$ of perfectly isotactic poly(vinyl alcohol) (iso-PVA) was studied by means of some model calculations according to the matrix method of Flory et al. These investigations were based on the assumption that the quality of solvent affected mainly the energy of the intramolecular hydrogen bond, while the magnitude of the interactions between other groups, hardly varied with the change of solvent. The individual conformation energies in a chain of iso-PVA were estimated from the analysis of structurally similar polymers, as well as the results obtained with 2,4-pentanediol. It was found that the characteristic ratio $\text{C =}\text{r}{}_0{}^2\text{nl}{}^2$ increased in non-polar solvents, with energy of the intramolecular hydrogen bond stabilizing the stretched zig-zag conformation of chain. Conversely, the characteristic ratio, monotonously decreased with increasing polarity of solvent to the value of about 6, typical of a flexible random coil. The existence of an analogous relationship, valid for other polymers, able to form an intramolecular hydrogen bond in the chain, was also discussed.     

Group therapy for patients with hysteria (Briquet's disorder)

It was found that group therapy helped patients with hysteria by (1) satisfying their need to talk (2) lessening their concern about their physical symptoms (3) giving them important knowledge of the illness (4) giving them new ways of handling the illness by themselves (5) giving them the support and the companionship of the other group members (6) reducing their need of medicines (7) reducing psychiatry visits (8) helping them to get along better with their families (9) increasing their self-confidence and (10) improving their mood.