Kamauf Custom Glass, Inc., manufactures custom windows primarily for homes and churches. Small repair jobs may take a few hours, but larger jobs may take hundreds of hours. How to schedule the jobs is a continuing issue. The scheduler has decided to see what insight can be gained by examining some common sequencing rules, namely FCFS, EDD, SPT, and LPT, on the criteria of average completion (flow) time, average lateness, and average number of jobs in the system. Her sample is the six jobs on the scheduler’s desk Monday morning. Assume that all jobs on the scheduler’s desk arrived today (day 100, which is a workday) in the order shown below. The estimated times to complete the jobs and their due dates are noted. L 0 1 

JOB DUE DATE

(DAYS)

DURATION (DAYS REQUIRED)

Alter piece (A) 130 5 Baptist Church (B) 350 100 Church of Christ (C) 140 17 Deacon’s window (D) 150 15 Entry way (special order) (E) 195 20 Frank’s Construction (kitchen window) (F) 175 35

a) Sequence the jobs according to the following decision rules:

FCFS, EDD, SPT, and LPT.

b) For the FCFS sequence, compute the average completion

(flow) time, average lateness, and average number of jobs in the system.

c) For the EDD sequence, compute the average completion

(flow) time, average lateness, and average number of jobs in the system.

d) For the SPT sequence, compute the average completion

(flow) time, average lateness, and average number of jobs in the system.

e) For the LPT sequence, compute the average completion

(flow) time, average lateness, and average number of jobs in the system.

f) Which is the best decision rule based on average completion

(flow) time?

g) Which is the best decision rule based on average lateness?