Question

3. A manager wants to assign tasks to workstations in order to achieve an hourly output rate of four units. The depart- working time of 56 minutes per hour. ment uses a Assign the tasks shown in the following precedence network (times are on the nodes and are in minutes) to workstations using the following heuristic rules: (i) Assign the task with the largest positional weight. (ii) Tiebreaker: "Assign the task with the longest time." If a tie still exists, choose randomly. b. What is the efficiency? a. 2 3 b A 7 d h 5 g f LO C LO

Answer 1

cycle time = 56/4 = 14 minutes

Number of workstations = task time / cycle time = 45/14 =4

Position weight

task	PW
a	23
b	20
c	18
d	25
e	18
f	29
g	24
h	14

task assignment

WS	Task	Time	Idle time
I	d,f	12	2
II	g,a,b	11	3
III	e,c	8	6
IV	h,i	14	0

2.

2.0 0 10 to {.0 Lo 2.0 0.2 0.9

Number of workstations needed = task time / cycle time = 4/1.5 =3

assignment

WS	Task	Time	Idle time
I	a,b,c	1.2	0.3
II	e,d,f,g,h	1.4	0.1
III	I,j,k,l	1.4	0.1

fraction idle time = 0.5 /4.5 = 0.1111

or 11.11%