1. Nahmias 3.7. A rolling production schedule implies that the schedule may be revised at the start of a new planning period. However, this does not mean that there is no value in knowing future demands. First, schedules may be frozen for several periods so that changes are not possible. Second, if high demands are anticipated, production may have to be ramped up well in advance to meet those demands. 2. Nahmias 3.12 (a) Net demand for July is 1250 - 500 + 300 = 1050. Adding 300 units to July’s demand guarantees that the ending inventory for each month never drops below 300. December’s demand has been increased by 400 so that we have 400 units left at the end of december. A person employed for a month produces 20*8/5 = 32 units. Column workers gives us the number of employees required to meet the net demand. Its calculated by dividing net demand by 32 and rounding up. Because of the rounding up we actually produce a little more than required. This is captured in the column Inv(-300). Because of this extra production we could actually reduce the employees required and this is shown in the column Workers(adj), e.g. in Sept, the net inventory surplus allows us to reduce one worker. Using this we can calculate the new production plan that gives the min number of workers without inccuring negative inventory. Table 1: Production plan 1 Workers Prod Inv−300 33 1056 6 35 1120 26 30 960 36 29 896 40 32 1024 64 49 1568 82
Month July Aug Sept Oct Nov Dec
Forc Dem 1250 1100 950 900 1000 1150
Net Dem 1050 1100 950 900 1000 1550
Workers (adj) 33 35 29 28 31 49
Prod (adj) 1056 1120 928 896 992 1568
(b) The ratio is the cum. net demand divided by the cumulative number of units produced by one worker rounded to the next largest integer (multiples of 32). The maximum of these numbers, 35, is the minimum constant workforce required to guarantee that no shortages occur. Assuming 35 workers each month gives the production and