Flow control protocols for integrated networks with partially observed voice traffic

The design of flow control protocols for integrated networks with partially observed voice traffic on the data link level is investigated. A closed Markovian queueing network with two classes of users and a preemptive resume queueing discipline for modeling the integrated link is introduced. The class of admissible flow control policies analyzed maximizes the average data link throughput subject to an average system time delay constraint on a finite horizon. A separation principle between the flow control policy and an estimate of the state of the voice traffic is derived. In particular, it is shown that the optimum control law is bang-bang and the conditional mean estimate of the state of the voice traffic is a sufficient statistic for the optimal control strategy. Since the complexity of the analytical results prohibits finding the explicit flow control policy, a suboptimum and easily implementable adaptive window flow control mechanism is proposed. The window size changes dynamically according to the estimated state of the voice traffic at the destination node. The robustness of the estimator, the dynamics of the window size, and the effectiveness of the suboptimum scheme are verified by means of simulations.     

Throughput improvement of STS-based MC DS-CDMA system with adaptive modulation

The throughput enhancement of space-time spreading (STS)-based multicarrier direct sequence code division multiple access (MC DS-CDMA) system is investigated in this paper. Adaptive modulation is performed to improve the data throughput of the system in Rayleigh fading channel. In this contribution, an analytical approach is proposed to compute a new expression for the bit error rate (BER) performance of the STS-based MC DS-CDMA system for QAM data. The other contribution of the paper is deriving a new analytical expression for the throughput enhancement and the BER performance of the adaptive modulated STS-based MC DS-CDMA system over Rayleigh fading channel. The novel expressions presented in this paper bring out the facility of evaluation of the proposed system with no need for more calculations and simulations.     

Two-dimensional side-by-side circular cylinders at moderate Reynolds numbers

In a companion article [1], we described computer simulations of the flow around 2 two-dimensional, tandem circular cylinders in a flow for 1?Re?20. In this article we adopt a similar approach to characterize the flow around side-by-side cylinders with surface-to-surface separation/diameter in the range 0.1 < s/D < 30. The results revealed some distinct and interesting features of the flow, which are completely different than those observed at higher Reynolds numbers.At low Reynolds numbers, 1?Re?5, for all gap spacings, the flow contains no regions of flow separation. At higher Re, four distinct flow behaviors were observed. For very small gap spacings, e.g. 0.1 < s/D < 0.6 at Re = 20, two elongated “detached vortices” form downstream of the cylinders. The drag coefficient increases sharply with the gap spacing. For gap spacings 0.6 < s/D < 0.7 at Re = 20, no vortices form anywhere in the flow. For gap spacings around s/D ≈ 1 separation regions form only on the inside portions of the cylinders. For larger gap spacings s/D > 1 the flow reverts to something similar to that around an isolated cylinder in the flow, i.e. two attached vortices on the rear side of each cylinder. In general, the drag coefficient increases as the gap spacing increases. At higher Reynolds number it is known that the cylinder lift coefficients decrease monotonically with gap spacing. In contrast, at these lower Reynolds number the lift coefficient curves rise to a maximum for 0.3 < s/D < 3 and then decrease monotonically for larger s/D.     

Effect of whey protein supplementation on levels of endocannabinoids and some of metabolic risk factors in obese women on a weight-loss diet: a study protocol for a randomized controlled trial

Background

Besides the effects of dietary long chain PUFA on circulating endocannabinoids concentrations, the impact of other nutrients on these system is not known and, whether changes in plasma endocannabinoids levels correlated with changes in body composition and biochemical metabolic risk factors in obese individuals, however, still remains to be characterized.

Methods

We will conduct a 2 months’ open label, parallel-group, randomized controlled trial to determine the effect of whey protein supplementation on levels of endocannabinoids, glycemic and lipid profile, inflammatory factors, adipocytokines and body composition in 60 premenopausal obese women on a weight-loss diet.

Conclusion

Due to strong relationship between endocannabinoids level and insulin resistance and obesity, in this trial, we will illustrate the other benefits of weight loss diet on health and metabolic risk factors. Also for the first, the effects of simultaneous weight loss diet and whey protein supplementation on these variables will be determined.

Trial registration

Iranian Registry of Clinical Trials IRCT2017021410181N8.

     

A comprehensive study of clustering ensemble weighting based on cluster quality and diversity

Pattern Analysis and Applications - Clustering as a major task in data mining is responsible for discovering hidden patterns in unlabeled datasets. Finding the best clustering is also considered as...     

Micromechanical sensor for studying heats of surface reactions, adsorption, and cluster deposition processes

We present a newly designed highly sensitive micromechanical sensor devoted to thermodynamic studies involving supported clusters. The thermally sensitive element of the sensor consists of a micromachined silicon cantilever array, onto which a thin metal film is evaporated. Due to the difference between the thermal expansion coefficients of silicon and the metal employed, thermal bending is observed when heat is exchanged with the cantilever. The sensitivity and the response time of the cantilever are studied as a function of the film material (gold or aluminum) and the thickness of the metal film. With our routinely prepared cantilevers, a minimum power of 120 nW is measurable with a submillisecond response time, corresponding to a limit of detection in the femtojoule range. The high sensitivity of the sensor is demonstrated by measuring the heat exchange which occurs during the deposition of clusters on the cantilever. Experimentally, we illustrate the 1,3-butadiene hydrogenation reaction using a cluster model catalysts created by soft-landing palladium clusters onto the cantilever surface.     

Infrared,Raman, electrical and thermal analysis of lithium sulphate monohydrate single crystals

In this work, single crystals of lithium sulphate monohydrate were grown by slow evaporation technique. Structural studies of the grown crystals were carried out by powder X-ray diffraction technique showing a monoclinic structure. Effect of temperature on the vibrational modes of different groups was observed and analyzed by Fourier transform infrared and Raman spectroscopy. The temperature dependent dielectric behaviour and ac conductivity of the grown crystals were also studied. The effect of temperature on the vibrational spectra as observed by Fourier transform infrared and Raman spectroscopy were correlated with the electrical behavior of the crystals. The relaxation studies were also undertaken using the complex-modulus M^* formalism which showed a thermally activated relaxation caused by the hopping motion of H⁺ ions in the crystal. All the observed characteristics were found to be closely related with water loss in the crystal structure. Thermal analysis of the grown crystal was carried out by using differential scanning calorimetric technique yielding various thermodynamic parameters such as ΔH, ΔS and ΔC_p. The activation energy for the dehydration step of lithium sulphate monohydrate was also evaluated by using Coats-Redfern integral method.     

Improving tinplate production

The production of tinplate (thickness <0.18 mm) by single-pass rolling is introduced. Measures for improving its surface quality and mechanical properties are developed.