Asymptotic-Diffusion Analysis for Retrial Queue with Batch Poisson Input and Multiple Types of Outgoing Calls

Author(s):  
Anatoly Nazarov ◽  
Tuan Phung-Duc ◽  
Svetlana Paul ◽  
Olga Lizura
Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 531 ◽  
Author(s):  
Alexander Moiseev ◽  
Anatoly Nazarov ◽  
Svetlana Paul

A multi-server retrial queue with a hyper-exponential service time is considered in this paper. The study is performed by the method of asymptotic diffusion analysis under the condition of long delay in orbit. On the basis of the constructed diffusion process, we obtain approximations of stationary probability distributions of the number of customers in orbit and the number of busy servers. Using simulations and numerical analysis, we estimate the accuracy and applicability area of the obtained approximations.


1999 ◽  
Vol 39 (7) ◽  
pp. 187-194 ◽  
Author(s):  
P. Lens ◽  
F. Vergeldt ◽  
G. Lettinga ◽  
H. Van As

The diffusive properties of mesophilic methanogenic granular sludge have been studied using diffusion analysis by relaxation time separated pulsed field gradient nuclear magnetic resonance (DARTS PFG NMR) spectroscopy. NMR measurements were performed at 22°C with 10 ml granular sludge at a magnetic field strength of 0.5 T (20 MHz resonance frequency for protons). Spin-spin relaxation (T2) time measurements indicate that three 1H populations can be distinguished in methanogenic granular sludge beds, corresponding to water in three different environments. The T2 relaxation time measurements clearly differentiate the extragranular water (T2 ≈ 1000 ms) from the water present in the granular matrix (T2 = 40-100 ms) and bacterial cell associated water (T2 = 10-15 ms). Self-diffusion coefficient measurements at 22°C of the different 1H-water populations as the tracer show that methanogenic granular sludge does not contain one unique diffusion coefficient. The observed distribution of self-diffusion coefficients varies between 1.1 × 10−9 m2/s (bacterial cell associated water) and 2.1 × 10−9 m2/s (matrix associated water).


2020 ◽  
Vol 51 (4) ◽  
Author(s):  
Sau May Wong ◽  
Walter H. Backes ◽  
Gerhard S. Drenthen ◽  
C. Eleana Zhang ◽  
Paulien H.M. Voorter ◽  
...  

2011 ◽  
Vol 115 (41) ◽  
pp. 11786-11792 ◽  
Author(s):  
Daisuke Takahashi ◽  
Shoji Yamashita ◽  
Om Prakash ◽  
Etsuko Nishimoto

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