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This paper presents an approximation method for analyzing open restricted queueing networks with exponential service time and Poisson arrivals. Analysis is made by node-by-node decomposition through the introduction of a pseudo-arrival rate and an effective service rate. The method is applied to example networks and evaluated by comparing the results obtained thereby with those by simulations or exact calculations. We find that this method provides a fairly good approximation procedure for obtaining system performance measures such as blocking probabilities, output rates, etc., in open restricted queueing networks.

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Congestion control plays an important role in the effective and stable operation of ATM networks. This paper first gives a historical overview of rate-based congestion control algorithms developed in the ATM Forum, showing how the current ATM Forum standard regarding the traffic management control methods is exploited, by these algorithm. Then, analytical approach is used to quantitatively evaluate their performance and show the effectiveness of the rate-based approach. In presenting the numerical examples, we emphasize that appropriate control parameter settings are essential for proper traffic management in an ATM network environment.

A recent study demonstrated a positive effect of apple polyphenol (APP) intake on muscle endurance of young-adult animals. While an enhancement of lipid metabolism may be responsible, in part, for the improvement, the contributing mechanisms still need clarification. Here we show that an 8-week intake of 5% (w/w) APP in the diet, up-regulates two features related to fiber type: the ratio of myosin heavy chain (MyHC) type IIx/IIb and myoglobin protein expression in plantaris muscle of 9-week-old male Fischer F344 rats compared to pair-fed controls (P < 0.05). Results were demonstrated by our SDS-PAGE system specialized for MyHC isoform separation and western blotting of whole muscles. Animal-growth profiles (food intake, body-weight gain, and internal-organ weights) did not differ between the control and 5% APP-fed animals (n = 9/group). Findings may account for the increase in fatigue resistance of lower hind limb muscles, as evidenced by a slower decline in the maximum isometric planter-flexion torque generated by a 100-s train of electrical stimulation of the tibial nerve. Additionally, the fatigue resistance was lower after 8 weeks of a 0.5% APP diet than after 5% APP, supporting an APP-dose dependency of the shift in fiber-type composition. Therefore, the present study highlights a promising contribution of dietary APP intake to increasing endurance based on fiber-type composition in rat muscle. Results may help in developing a novel strategy for application in animal sciences, and human sports and age-related health sciences.