Question 1

When a set of jobs must pass through two workstations whose sequence is fixed, ________ is the sequencing rule most commonly applied.

Accepted Answer

A)  critical ratio 
B)  earliest due date 
C)  first come, first served 
D)  slack time remaining 
E)  Johnson's rule 
A)  critical ratio 
B)  earliest due date 
C)  first come, first served 
D)  slack time remaining 
E)  Johnson's rule E

Question 2

A practitioner of family medicine begins her day with five patients needing urgent care. She does a very brief assessment of what each patient appears to need and estimates the time required of each. None of the cases is life-threatening, and so she determines to take the five in the order that they arrived at the clinic. The data for these patients, in the order they arrived, is Patient A, 30 minutes; Patient B, 40 minutes; Patient C, 10 minutes; Patient D, 50 minutes; and Patient E, 15 minutes. a. If it is now 8:00 a.m., at what time will the doctor be finished with all five of these emergencies? b. How much time will the five patients have collectively spent waiting? c. How much less time would have been spent waiting if the doctor had taken the patients according to shortest processing time?

Accepted Answer

(a) Using first come, first served, all five patients will be finished in 145 minutes, or at 10:25 a.m. (b)Total flow time is 455 minutes, of which 145 is for processing, and the remaining 310 is waiting time. (c) If the doctor had used shortest processing time, the total flow time would have been 330 minutes, of which 185 is waiting time. In both cases, the doctor finished all patients at 10:25 a.m. A supporting table for each rule appears below.
 $$\begin{array} { | l | r | r | r | r | r | } 
\hline & \text { Machine 1 } & \text { Due Date } & \text { \#Opns } & \text { Order } & \text { Flow time } \
\hline \text { A } & 30 & 0 & 0 & \text { first } & 30 \
\hline \text { B } & 40 & 0 & 0 . & \text { second } & 70 \
\hline \text { C } & 10 & 0 & 0 & \text { third } & 80 \
\hline \text { D } & 50 & 0 & 0 . & \text { fourth } & 130 \
\hline \text { E } & 15 & 0 . & 0 . & \text { fifth } & 145 \
\hline \text { Total } & & & & & 455 \
\hline \text { Average } & & & & & 91 \
\hline \text { Average \# jobs in } & 3.1379 & & & & \
\hline
\end{array}$$ Sequence: A, B, C, D, E
 $$\begin{array} { | l | r | r | r | r | r | } 
\hline & \text { Machine 1 } & \text { Due Date } & \text { \#Opns } & \text { Order } & \text { Flow time } \
\hline \text { A } & 30 & 0 & 0 & \text { first } & 55 \
\hline \text { B } & 40 & 0 . & 0 & \text { second } & 95 \
\hline \text { C } & 10 & 0 & 0 & \text { third } & 10 \
\hline \text { D } & 50 & 0 & 0 & \text { fourth } & 145 \
\hline \text { E } & 15 & 0 & 0 & \text { fifth } & 25 \
\hline \text { Total } & & & & & 330 \
\hline \text { Average } & & & & & 66 \
\hline \text { Average \# jobs in } & 2.2759 & & & & \
\hline
\end{array}$$ Sequence; C, E, A, B, D

Question 3

Explain, in your own words, how backward scheduling and forward scheduling differ.

Accepted Answer

Forward scheduling starts the schedule as soon as the requirements are known. Backward scheduling begins with the due date, scheduling the final operation first and proceeding in the reverse order.

Question 4

At Morgan's Transformer Rebuilding, a set of five jobs is ready for dispatching to a machine centre. The processing times and due dates for the jobs are given in the table below. Use shortest processing time to sequence the jobs, and calculate the average completion time, the average job lateness, and the average number of jobs in the machine centre.
 $$\begin{array} { | c | c | c | } 
\hline \text { Job } & \text { Work Time (days) } & \text { Due Date (days) } \
\hline \text { A } & 15 & 38 \
\hline \text { B } & 13 & 28 \
\hline \text { C } & 7 & 20 \
\hline \text { D } & 18 & 50 \
\hline \text { E } & 9 & 15 \
\hline
\end{array}$$

Accepted Answer

The optimal sequence is C-E-B-A-D. The a

Question 5

Air Canada uses mathematical short-term scheduling techniques and a high-tech nerve centre to manage the rapid rescheduling necessary to cope with weather delays and similar disruptions.

Accepted Answer

A) True 
 B)False

Question 6

Given the following chart of jobs assigned with Johnson's rule suppose that all the jobs (A, B, C, etc) could be evenly divided into two tasks (such as A1 and A2, B1 and B2, etc). Suppose job B is divided into jobs B1 and B2, each with a body work time of 4.5 hours and a paint time of 2 hours. How much is makespan reduced by this splitting of B?

Accepted Answer

B1 could start on paint at time = 34.5 (

Question 7

Use Johnson's rule to determine the optimal sequencing for the five jobs to be processed on two machines in a fixed order (Machine 1 before Machine 2). The processing times in hours are given in the table below.
a. What is the optimal sequence?
b. What is the total flow time for this sequence?
c. Which job is the first to be scheduled? Is it scheduled to be the first job or the last? Explain.
 $$\begin{array} { | c | c | c | } 
\hline \text { Job } & \text { Machine 1 } & \text { Machine 2 } \
\hline \text { A } & 10 & 11 \
\hline \text { B } & 8 & 17 \
\hline \text { C } & 14 & 10 \
\hline \text { D } & 13 & 7 \
\hline \text { E } & 10 & 8 \
\hline \text { F } & 25 & 9 \
\hline \text { G } & 6 & 15 \
\hline
\end{array}$$

Accepted Answer

(a,b) The optimal sequence is

Question 8

A manufacturer has the following jobs waiting on a single work centre. The firm has not decided which dispatching rule to apply in order to prioritize the jobs and fix them into the schedule. Processing time in 15-minute time blocks and due date for each job are in the table below.
 $$\begin{array} { | c | c | c | } 
\hline & \text { Time } & \text { Due Date } \
\hline \text { Job 1 } & 5 & 17 \
\hline \text { Job 2 } & 4 & 20 \
\hline \text { Job 3 } & 3 & 16 \
\hline \text { Job 4 } & 7 & 9 \
\hline \text { Job 5 } & 3 & 6 \
\hline \text { Job 6 } & 5 & 7 \
\hline
\end{array}$$ a. Complete the following table. Show your supporting calculations below.
b. Which dispatching rule has the best score for flow time? for work in process (jobs in the system)? for lateness?
c. Is there ANY sequence that can avoid all lateness? Explain or provide an example.
 $\begin{array}{|l|l|l|l|l|}
\hline\text { Dispatching } & & \text { Average } & \text { Average } & \text { Average } \
\text { Rule } & \text { Job Sequence } & \text { Flow Time } & \text { Number of Jobs } & \text { Lateness } \
\hline \text { EDD } & & & & \
\hline \text { SPT } & & & & \
\hline \text { LPT } & & & & \
\hline
\end{array}$

Accepted Answer

(a) The results appear in the table belo

Question 9

Three jobs are to be assigned to three machines. Cost for each job-machine combination appears in the table below. Perform the first two steps of the assignment method (subtract the smallest number in each row and subtract the smallest number in each column; then cover with straight lines). At this point in the problem-solving process $$\begin{array} { | l | l | l | l | } 
\hline & \text { Machine A } & \text { Machine B } & \text { Machine C } \
\hline \text { Tob 1 } & 11 & 14 & 6 \
\hline \text { Tob 2 } & 8 & 10 & 11 \
\hline \text { Job 3 } & 9 & 12 & 7 \
\hline
\end{array}$$

Accepted Answer

A)  the row for Job 1 contains the values 5, 6, and 0. 
B)  calculations are complete, and the problem is ready for an optimal set of assignments. 
C)  the column for Machine B indicates that it should be retired. 
D)  Job 1 should be performed on Machine B. 
E)  Job 1 should be performed on Machine A. 
A)  the row for Job 1 contains the values 5, 6, and 0. 
B)  calculations are complete, and the problem is ready for an optimal set of assignments. 
C)  the column for Machine B indicates that it should be retired. 
D)  Job 1 should be performed on Machine B. 
E)  Job 1 should be performed on Machine A.

Question 10

In repetitive manufacturing, what are the advantages of level material use? Does level material use have any role in intermittent process facilities?

Accepted Answer

The five advantages are:
1. Lower invent

Question 11

The following jobs are waiting to be processed at your work centre, which cleans valve body castings. Job numbers are assigned sequentially upon arrival in the facility (a missing number means that job does not require your work centre). All dates are specified as days from Today.
 $$\begin{array} { | c | c | c | } 
\hline \text { Job } & \text { Due Date } & \begin{array} { c } 
\text { Duration } \
\text { (days) }
\end{array} \
\hline 101 & 44 & 14 \
\hline 102 & 31 & 12 \
\hline 104 & 27 & 11 \
\hline 107 & 32 & 8 \
\hline 108 & 37 & 10 \
\hline
\end{array}$$ a. In what sequence should the jobs be processed according to the FCFS scheduling rule?
b. In what sequence should the jobs be processed according to the EDD scheduling rule?
c. In what sequence should the jobs be processed according to the SPT scheduling rule?
d. In what sequence should the jobs be processed according to the LPT scheduling rule?

Accepted Answer

FCFS: 101, 102, 104, 107, 108

Question 12

The following jobs are waiting to be processed at your work centre, which cleans valve body castings. Job numbers are assigned sequentially upon arrival in the facility (a missing number means that job does not require your work centre). All dates are specified as days from Today.
 $$\begin{array} { | c | c | c | } 
\hline \text { Job } & \text { Due Date } & \begin{array} { c } 
\text { Duration } \
\text { (days) }
\end{array} \
\hline 101 & 43 & 10 \
\hline 102 & 34 & 12 \
\hline 104 & 37 & 11 \
\hline 107 & 32 & 7 \
\hline 108 & 37 & 15 \
\hline
\end{array}$$ a. In what sequence should the jobs be processed according to the FCFS scheduling rule?
b. In what sequence should the jobs be processed according to the EDD scheduling rule?
c. In what sequence should the jobs be processed according to the SPT scheduling rule?
d. In what sequence should the jobs be processed according to the LPT scheduling rule?
e. In what sequence should the jobs be processed according to the critical ratio scheduling rule?

Accepted Answer

FCFS: 101, 102, 104, 107, 108

Question 13

If an assignment problem consists of 6 workers and 7 projects

Accepted Answer

A)  one worker will not get a project assignment. 
B)  one worker will be assigned two projects. 
C)  each worker will contribute work toward the seventh project. 
D)  one project will not get a worker assigned. 
E)  The problem cannot be solved by assignment method. 
A)  one worker will not get a project assignment. 
B)  one worker will be assigned two projects. 
C)  each worker will contribute work toward the seventh project. 
D)  one project will not get a worker assigned. 
E)  The problem cannot be solved by assignment method.

Question 14

Briefly describe how "the unexpected" makes short-term scheduling at Air Canada a challenge. Also describe how Air Canada meets that challenge, and achieves competitive advantage through short-term scheduling.

Accepted Answer

The unexpected refers to delays and canc

Question 15

Which of the following files tracks work order progress?

Accepted Answer

A)  work-centre master files 
B)  routing files 
C)  item master files 
D)  control files 
E)  ordering file 
A)  work-centre master files 
B)  routing files 
C)  item master files 
D)  control files 
E)  ordering file

Question 16

EDD stands for

Accepted Answer

A)  earliest due date. 
B)  earliest design date. 
C)  earliest detrimental date. 
D)  earliest decision date. 
E)  earliest distribution date. 
A)  earliest due date. 
B)  earliest design date. 
C)  earliest detrimental date. 
D)  earliest decision date. 
E)  earliest distribution date.

Question 17

An approach to sequencing that can handle the situation where jobs must pass through two or more work centres in a fixed sequence is ________.

Accepted Answer

The answer of An approach to sequencing that can handle...

Question 18

________ means frequent, high-quality, small lot sizes that contribute to just-in-time production.

Accepted Answer

The answer of ________ means frequent, high-quality, small lot sizes...

Question 19

Five jobs are waiting for processing through two work centres. Their processing time (in minutes) at each work centre is contained in the table below. Each job requires work centre Alpha before work centre Beta. According to Johnson's rule, what is the optimum sequence of jobs and the minimum time for completion of all jobs? $$\begin{array} { | c | c | c | } 
\hline \text { Job } & \text { Alpha } & \text { Beta } \
\hline R & 20 & 10 \
\hline \mathrm { S } & 25 & 35 \
\hline \mathrm { T } & 50 & 20 \
\hline \mathrm { U } & 15 & 35 \
\hline \mathrm { V } & 55 & 75 \
\hline
\end{array}$$

Accepted Answer

A)  V-T-S-U-R; 225 
B)  U-R-T-S-V; 175 
C)  R-S-T-U-V; 240 
D)  U-S-V-T-R; 200 
E)  V-U-T-S-R; 250 
A)  V-T-S-U-R; 225 
B)  U-R-T-S-V; 175 
C)  R-S-T-U-V; 240 
D)  U-S-V-T-R; 200 
E)  V-U-T-S-R; 250

Question 20

The work-centre master file contains data such as capacity and efficiency.

Accepted Answer

A) True 
 B)False

When a set of jobs must pass through two workstations whose sequence is fixed, ________ is the sequencing rule most commonly applied.

Explain, in your own words, how backward scheduling and forward scheduling differ.

Air Canada uses mathematical short-term scheduling techniques and a high-tech nerve centre to manage the rapid rescheduling necessary to cope with weather delays and similar disruptions.

In repetitive manufacturing, what are the advantages of level material use? Does level material use have any role in intermittent process facilities?

If an assignment problem consists of 6 workers and 7 projects

Briefly describe how "the unexpected" makes short-term scheduling at Air Canada a challenge. Also describe how Air Canada meets that challenge, and achieves competitive advantage through short-term scheduling.

Which of the following files tracks work order progress?

EDD stands for

An approach to sequencing that can handle the situation where jobs must pass through two or more work centres in a fixed sequence is ________.

________ means frequent, high-quality, small lot sizes that contribute to just-in-time production.

The work-centre master file contains data such as capacity and efficiency.

Operations and Productivity

Operations Strategy in a Global Environment

Project Management

Forecasting

Design of Goods and Services

Managing Quality

Process Strategy and Sustainability

Location Strategies

Layout Strategies

Human Resources, Job Design, and Work Measurement

Supply-Chain Management

Inventory Management

Aggregate Planning

Material Requirements Planning Mrp and Erp

Lean Operations

Maintenance and Reliability

Decision-Making Tools

Linear Programming

Transportation Models

Waiting-Line Models

Learning Curves

Simulation

Supply Chain Management Analytics

Sustainability in the Supply Chain

Statistical Process Control

Capacity and Constraint Management

Filters

Exam 15: Short-Term Scheduling

When a set of jobs must pass through two workstations whose sequence is fixed, ________ is the sequencing rule most commonly applied.

Explain, in your own words, how backward scheduling and forward scheduling differ.

Air Canada uses mathematical short-term scheduling techniques and a high-tech nerve centre to manage the rapid rescheduling necessary to cope with weather delays and similar disruptions.

In repetitive manufacturing, what are the advantages of level material use? Does level material use have any role in intermittent process facilities?

If an assignment problem consists of 6 workers and 7 projects

Briefly describe how "the unexpected" makes short-term scheduling at Air Canada a challenge. Also describe how Air Canada meets that challenge, and achieves competitive advantage through short-term scheduling.

Which of the following files tracks work order progress?

EDD stands for

An approach to sequencing that can handle the situation where jobs must pass through two or more work centres in a fixed sequence is ________.

________ means frequent, high-quality, small lot sizes that contribute to just-in-time production.

The work-centre master file contains data such as capacity and efficiency.

Operations and Productivity

Operations Strategy in a Global Environment

Project Management

Forecasting

Design of Goods and Services

Managing Quality

Process Strategy and Sustainability

Location Strategies

Layout Strategies

Human Resources, Job Design, and Work Measurement

Supply-Chain Management

Inventory Management

Aggregate Planning

Material Requirements Planning Mrp and Erp

Lean Operations

Maintenance and Reliability

Decision-Making Tools

Linear Programming

Transportation Models

Waiting-Line Models

Learning Curves

Simulation

Supply Chain Management Analytics

Sustainability in the Supply Chain

Statistical Process Control

Capacity and Constraint Management

Filters