Miscellaneous
Learning Curve for Manufacturing Cost
C
= Cost of the nth unit, C
n
n = number of units, r = learning factor.
k = ln r / ln 2,
=
C
the
ij
C
1
=
C
ij
−
j
This formula is only approximate and may give appreciable error at small i.
Queuing and Waiting Theory
n = number of servers.
λ
= arrival rate of customers (Poisson input).
µ
=service rate for each server (exponential service).
ρ
= Intensity factor =
P = Probability that all servers are idle.
0
P = Probability that all servers are busy.
b
L = Average number of customers in queue.
q
L = Average number of customers in the system (waiting and being served).
T = Average waiting time in queue.
q
T = Average total time through the system.
P(t) = Probability of waiting longer than time t.
−
n
1
∑
=
P
0
=
k
0
ρ
=
P
b
n
!
1
ρ
P
=
L
q
−
n
( )
=
P
t
P
e
b
1
k
=
C
C
n
n
1
average
cost
of
the
i
+
+
k
1
k
1
−
j
i
+
i
k
1
λ
µ
/
−
1
k
n
ρ
ρ
+
ρ
k!
−
n
!
1
n
n
P
0
ρ
−
n
b
ρ
=
+
,
L
L
,
q
ρ
(
)
µ
λ
−
−
n
t
= Cost of the first unit.
th through
j
th
unit.
ρ
(
< n for valid results).
L
q
λ
T =
T =
/ L
,
q
λ
Appendix B 165