Scheduling Exercises

Based on Heizer and Reinder Chapter $13$ and $15$

$1.$ Develop another plan for the roofer, for this plan the firms wants to maintain a constant

force of $6$ and subcontracting to meet remaining demand

$($a$)$ Plan $5$: Constant workforce of $6$ persons; subcontract to meet extra demand

Month

Expected

Demand

Production

Days

Demand

Per Day

Jan $9002241$

Feb $7001839$

Mar $8002138$

Apr $1,2002157$

May $1,5002268$

Jun $1,1002055$

$6,200124$

Cost Information

Inventory carrying cost $ $5$ per unit per month

Subcontracting cost per unit $$10$ per unit

Average pay rate $ $5$ per hour $($$$40$ per

day$)$

Overtime pay rate $ $7$ per hour

$($above $8$ hours per day$)$

Labor$-$hours to produce a unit $1\mathrm{.}6$ hours per unit

Cost of increasing daily production

rate $($hiring and training$)$

$$300$ per unit

Cost of decreasing daily production

rate $($layoffs$)$

$$600$ per unit

$2|$ M S O p e r a t i o n s M a n a g e m e n t

$2.(15\mathrm{.}10)$ The following jobs are waiting to be processed at the same machine center. Jobs

are logged as they arrive:

In what sequence would the jobs be ranked according to the following decision rules: $($a$)$ FCFS$.$

$($b$)$ EDD $($c$)$ SPT and $($d$)$ LPT$.$ Assume that all jobs arrive on day $275.$ Which decision is best

and why?

$3|$ M S O p e r a t i o n s M a n a g e m e n t

$3(15\mathrm{.}18).$ Six jobs are to be processed through a two$-$step operation.

Use Johnson rule to determine optimal sequence