Analysis of M/M/1 Queue with Finite Capacity: A Detailed Study
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This document explores the dynamics of an M/M/1 queuing system with finite capacity, specifically focusing on a workstation that receives parts from a conveyor. The system has a buffer capacity allowing for six parts (five in addition to the one being processed). Utilizing a Poisson arrival process at a rate of one part per minute and an exponential service time with a mean of 45 seconds, we derive critical metrics such as average waiting time (W) and system capacity (L). This analysis contributes valuable insights into optimizing queuing systems in operational environments.
Analysis of M/M/1 Queue with Finite Capacity: A Detailed Study
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l m - l = n p ( ) ( ) n m m l l 2 = L = L m - l q l m - l ( ) 1 l = W = W m - l q l m - l ( ) Model
l + m = m + l p p p p 0 2 1 1 l = m p p 0 1 l = m p p - N 1 N M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N State Balance Eq. 0 1 N
N å = p 1 n = 0 n l N å = n 1 p ( ) 0 m = 0 n M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N Now,
M/M/1 Queue Finite Capacity • Workstation receives parts form a conveyor. Station has buffer capacity for 5 parts in addition to the 1 part to work on (N=6). Parts arrive in accordance with a Poisson process with rate of 1 / min. Service time is exp. with mean = 45 sec. (m = 4/3). 0 1 2 3 5 6
+ - 1 N N 1 x å = l n N x å = n - 1 p ( ) 1 x = 0 0 n m = 0 n M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N Recall,
l + - N 1 1 ( ) m = 1 p l l N 0 å - = n 1 ( ) 1 p ( ) m 0 m = 0 n M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N
l - 1 ( ) m = p l 0 + - N 1 1 ( ) m l + - N 1 1 ( ) m = 1 p l 0 - 1 ( ) m M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N
l - 1 ( ) m = p l 0 + - N 1 1 ( ) m l - 1 ( ) l m = n p ( ) l n m + - N 1 1 ( ) m M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N
l - 1 ( ) l m N N å å = = n L np n ( ) l n m + - 1 N 1 ( ) = = 0 0 n n m l - 1 ( ) l m N å = n n ( ) l m + - 1 N 1 ( ) = 0 n m M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N
l l + l + - + 1 N N [ 1 N ( ) ( N 1 )( ) ] m m = L l + m - l - 1 N ( )[ 1 ( ) ] m M/M/1 Queue Finite Capacity 0 1 2 3 N-1 N Miracle 37 b
l = ( ) 0 . 75 m M/M/1 Queue Finite Capacity • Workstation receives parts form a conveyor. Station has buffer capacity for 5 parts in addition to the 1 part to work on (N=6). Parts arrive in accordance with a Poisson process with rate of 1 / min. Service time is exp. with mean = 45 sec. (m = 4/3). 0 1 2 3 5 6
+ - 7 6 1 [ 1 6 ( 0 . 75 ) ( 7 )( 0 . 75 ) ] = = L 1 . 92 l - - 7 ( 1 . 33 1 ) [ 1 ( 0 . 75 ) ] = ( ) 0 . 75 m M/M/1 Queue Finite Capacity • l = 1 N = 6 • m = 4/3 = 1.33 0 1 2 3 5 6
0 1 2 3 5 6 L = = W 1 . 92 l q = = W 1 . 21 q l 1 = + = W W 1 . 96 q m = l = L W * 1 . 96 ??? Little’s Revisted L
0 1 2 3 5 6 ¥ å l = l p n n = 0 n M / M / 1 ¥ ¥ å å l = l = l = l p p n n = = 0 0 n n Little’s Revisited l l l l l l
0 1 2 3 5 6 ¥ å l = l p n n = 0 n M / M / 1 / 6 l = l + l + l + l + l + l p p p p p p 0 1 2 3 4 5 = l + + + + + ( p p p p p p ) 0 1 2 3 4 5 = l - ( 1 p ) 6 Little’s Revisited l l l l l l
0 1 2 3 5 6 l = - 1 ( 1 p ) 6 = - 1 ( 1 . 051 ) = 0 . 949 Little’s Revisited l l l l l l
0 1 2 3 5 6 l = 0 . 949 L = = W 2 . 025 l Little’s Revisited l l l l l l
0 1 2 3 5 6 l = 0 . 949 = W 2 . 025 1 = - W W q m = - 2 . 025 0 . 75 = 1 . 275 Little’s Revisited l l l l l l
0 1 2 3 5 6 l = 0 . 949 = W 2 . 025 = W 1 . 275 q = l L W q q = . 949 ( 1 . 275 ) = 1 . 210 Little’s Revisited l l l l l l