Deck 15: Short-Term Scheduling

Question 1

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

Answer 1

True

Question 2

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

Answer 2

The unexpected refers to delays and cancellations that are largely weather-related.These events require rapid rescheduling in order to keep operations going and to keep passengers from becoming too inconvenienced.Delta's solution involves a high-tech nerve center of computers and communications gear,and it uses mathematical models to reroute and reschedule as quickly as possible.

Question 3

Forward scheduling:

A)begins with a delivery date,then offsets each operation one at a time,in reverse order.
B)has the same meaning as "finite loading."
C)is often used in service environments such as catering a banquet or scheduling surgery.
D)starts the schedule as soon as the job requirements are known.
E)produces a schedule only if it meets the due date.

Answer 3

D

Question 4

The correct sequence from longest to smallest duration scheduling is:

A)capacity planning,aggregate planning,master schedule,short-term scheduling.
B)aggregate planning,capacity planning,master schedule,short-term scheduling.
C)master schedule,capacity planning,aggregate planning,short-term scheduling.
D)master schedule,aggregate planning,capacity planning,short-term scheduling.
E)capacity planning,master schedule,aggregate planning,short-term scheduling.

Question 5

The benefits of effective scheduling include lower cost,faster throughput,and dependable delivery.

Question 6

Short-term schedules are prepared:

A)directly from the aggregate plans.
B)directly from the capacity plans.
C)from inventory records for items that have been used up.
D)from master schedules,which are derived from aggregate plans.
E)from the purchasing plans.

Question 7

One criterion for developing effective schedules is minimizing completion time.

Question 8

Forward scheduling is the scheduling of:

A)the end items or finished products.
B)jobs as soon as the requirements are known.
C)the start items or component parts.
D)the final operation first beginning with the due date.
E)jobs according to their profit contributions.

Question 9

Which of the following statements regarding scheduling at Delta Airlines is FALSE?

A)About one flight in twenty is disrupted by weather events.
B)Schedule changes at one airport have a ripple effect that may have impacts in many others.
C)Delta's high-tech computer and communications system is located in Atlanta.
D)Delta's rapid rescheduling uses mathematical scheduling models.
E)Delta's rapid rescheduling promotes air safety and limits traveler inconvenience,but has not resulted in money savings for Delta.

Question 10

What makes short-term scheduling of strategic importance?

Question 11

Which of the following considers process capacity when scheduling?

A)cap loading
B)constrained loading
C)capacitated loading
D)backward loading
E)finite loading

Question 12

With forward scheduling,jobs are scheduled as late as possible within the time allowed by the customer due dates.

Question 13

Process-focused facilities and repetitive facilities generate forward-looking schedules,but process-focused facilities do this with JIT and kanban while repetitive facilities generally use MRP.

Question 14

What is the objective of scheduling?

A)maximize quality
B)minimize cost
C)minimize response time
D)prioritize and allocate demand to available facilities
E)minimize lead time

Question 15

Which of the following is NOT a key direct benefit from effective internal or external scheduling?

A)lower cost
B)greater use of assets
C)more dependable delivery
D)higher quality
E)added flexibility

Question 16

The short-term scheduling activity called "loading":

A)assigns dates to specific jobs or operations steps.
B)specifies the order in which jobs should be done at each center.
C)assigns jobs to work centers
D)assigns workers to jobs.
E)assigns workers to machines.

Question 17

Short-term scheduling is important to efficiency and to cost reduction,but its impact is not of strategic importance.

Question 18

Which of the following is not an effectiveness criterion for scheduling?

A)minimizing customer waiting time
B)minimizing completion time
C)minimizing WIP inventory
D)maximizing utilization
E)maximizing flow time

Question 19

In the sequence of decisions that affect scheduling,________ is (are)the immediate follower(s)of the master schedule (or master production schedule).

Question 20

________ scheduling begins with the due date and schedules the final operation first and the other job steps in reverse order.

Question 21

What is a method of input-output control that uses a system of cards to limit the amount of work at a work center and also to control lead time and monitor backlog?

A)the assignment method
B)backward scheduling
C)forward scheduling
D)ConWIP cards
E)level material use

Question 22

A work center had actual input of 280 hours and actual output of 270 hours.What is the change in backlog?

A)10
B)-10
C)0
D)1.037
E)Unable to determine with the given information

Question 23

If an assignment problem consists of 6 workers and 7 projects:

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 24

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

Question 25

A work center had planned outputs of 10,15,13,and 20 hours with actual outputs of 12,14,13,and 18 hours.What is the cumulative deviation in output?

A)0
B)1
C)-1
D)58
E)Unable to determine with the given information

Question 26

A Gantt load chart shows the loading and idle time of several departments,machines,or facilities.

Question 27

There are two jobs to be assigned to two workers.The profit for worker A on job 1 is $5 and on job 2 is $8.The profit for worker B on job 1 is $10 and on job 2 is $12.How should the work be divided using the assignment method?

A)worker A assigned to job 1 and worker B assigned to job 2
B)worker A assigned to job 2 and worker B assigned to job 1
C)worker A gets both jobs 1 and 2
D)worker B gets both jobs 1 and 2
E)unable to determine

Question 28

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:

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 29

________ is the assignment of jobs to work or processing centers.

Question 30

The assignment method is:

A)a method to highlight overloads in a given work center.
B)a computerized method of determining appropriate tasks for an operation.
C)a form of linear programming for optimally assigning tasks or jobs to resources.
D)the same thing as the Gantt schedule chart.
E)a method for achieving a balance between forward and backward scheduling.

Question 31

A work center is interested in limiting work-in-process by not allowing production to start again until the current batch is finished.The best solution most likely involves:

A)MRP.
B)ConWIP cards.
C)Gantt charts.
D)Johnson's rule.
E)the assignment method.

Question 32

Gantt charts are useful for scheduling jobs,but not for loading them.

Question 33

If an assignment problem consists of 5 workers and 4 projects:

A)one worker will not get a project assignment.
B)one project will be assigned two workers.
C)the fifth worker will split time among the four projects.
D)one project will not get a worker assigned.
E)The problem cannot be solved by assignment method.

Question 34

Compare short-term scheduling at process-focused,repetitive,and product-focused facilities.

Question 35

The constant work-in-process (ConWIP)card aids input-output control by limiting the amount of work in a work center.

Question 36

The assignment method provides an optimum,one-to-one assignment of jobs to resources.

Question 37

What is a scheduling technique used to achieve an optimum,one-to-one matching of tasks and resources?

A)the assignment method
B)Johnson's rule
C)the CDS algorithm
D)the appointment method
E)the reservation method

Question 38

Which of the following is NOT required to be known in order to schedule process-focused facilities?

A)the sequence of work
B)which workers are assigned to each work center
C)the time required for each item
D)the capacity of each work center
E)the availability of each work center

Question 39

If job 5 takes 3,4 or 5 hours to be completed by workers A,B,and C,respectively,what would the row values for job 5 be after performing Step 1A of the assignment method?

A)3,4,5
B)8,9,10
C)0,1,2
D)6,7,8
E)1,4/3,5/3

Question 40

Which of the following is an aid used to monitor jobs in progress?

A)a Gantt load chart
B)the assignment method
C)a Gantt schedule chart
D)Johnson's rule
E)a Gantt progress chart

Question 41

Using LPT priority would result in what sequence for Jobs A,B,C,and D if their process times are 4,6,5,and 2 respectively?

A)ABCD
B)DCBA
C)DACB
D)DABC
E)BCAD

Question 42

The jobs listed below need to be completed.Assume that it is now day 140.If the jobs are sequenced according to the shortest processing time rule,what is the average completion time?

A)47.6 days
B)60.2 days
C)94.0 days
D)2.5 days
E)238.0 days

Question 43

The critical ratio sequencing rule prioritizes the jobs based on the importance or value of the customers who have placed the orders.

Question 44

EDD stands for what?

A)earliest due date
B)earliest design date
C)earliest detrimental date
D)earliest decision date
E)economic date determination

Question 45

Johnson's rule sequences a set of jobs through two different machines or work centers in the same order.

Question 46

Which of the following dispatching rules ordinarily gives the best results when the criterion is lowest time for completion of the full sequence of jobs?

A)shortest processing time (SPT)
B)critical ratio (CR)
C)first in,first out (FIFO)
D)first come,first served (FCFS)
E)longest processing time (LPT)

Question 47

Orders are processed in the sequence in which they arrive if (the)________ rule sequences the jobs.

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

Question 48

The jobs listed below need to be completed.Assume that it is now day 140.If the jobs are sequenced according to the longest processing time rule,what is the lateness of job A?

A)0.0 days
B)24.0 days
C)7.4 days
D)10.0 days
E)11.6 days

Question 49

What is the difference between a Gantt load chart and a Gantt scheduling chart?

Question 50

Identify the major disadvantages of the Gantt load chart.

Question 51

The president of a consulting firm wants to minimize the total number of hours it will take to complete four projects for a new client.Accordingly,she has estimated the time it should take for each of her top consultants-Charlie,Gerald,Johnny,and Rick-to complete any of the four projects,as follows:
(a)What is the total number of hours required by the following arbitrary assignment?
Charlie→B;Gerald→A;Johnny→D;Rick→C
(b)What is the optimal assignment of consultants to projects? (Use the assignment method. )
(c)For the optimal schedule,what is the total number of hours it will take these consultants to complete these projects?

Question 52

What is input-output control?

Question 53

________ cards are used to control the amount of work in a work center,aiding input-output control.

Question 54

Earliest due date is a shop floor dispatching (sequencing)rule that relates the time available to complete a job to the amount of work left to be completed.

Question 55

What is the assignment method?

Question 56

Dispatching rules are typically judged by four effectiveness criteria: average completion time,utilization,average number of jobs in the system,and average job lateness.

Question 57

The ________ is a special class of linear programming models that involves assigning tasks or jobs to resources.

Question 58

________ are planning charts used to schedule resources and allocate time.

Question 59

Lockport Marine Services,Inc.wishes to assign a set of jobs to a set of machines.The following table provides data on the cost of production of each job when performed on a specific machine.
(a)Determine the set of assignments that minimizes production cost.
(b)What is the total production cost of your assignments?

Question 60

Machines A,B,C,and D have been in use for several years,while machine E is new.The following table provides data on the value of production of each job when performed on a specific machine.
(a)Determine the set of assignments that maximizes production value.
(b)What is the total production value of your assignments?
(c)Which machine should be retired (i.e. ,gets no assignment)?

Question 61

Five jobs are waiting to be processed.Their processing times and due dates are given below.Using the earliest due date dispatching rule,in which order should the jobs be processed?

A)C,E,A,D,B
B)A,B,C,D,E
C)B,D,A,E,C
D)C,B,A,E,D
E)B,D,A,C,E

Question 62

Which of the following is an advantage of the FCFS dispatching rule when used in services?

A)FCFS maximizes utilization.
B)FCFS minimizes the average number of jobs in the system.
C)FCFS minimizes the average lateness of all jobs.
D)FCFS maximizes the number of jobs completed on time.
E)FCFS seems fair to customers.

Question 63

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

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

Question 64

Five jobs are waiting for processing through two work centers.Their processing time (in minutes)at each work center is contained in the table below.Each job requires work center Alpha before work center Beta.According to Johnson's rule,what is the optimum sequence of jobs and the minimum time for completion of all jobs?

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)R-U-T-S-V;175

Question 65

Five jobs are waiting to be processed.Their processing times and due dates are given below.Using the shortest processing time dispatching rule,in which order should the jobs be processed?

A)A,B,C,D,E
B)C,E,A,D,B
C)B,D,A,E,C
D)D,A,E,B,C
E)C,E,A,B,D

Question 66

The priority rule that appears fair to customers in service systems is ________.

Question 67

Flow time represents the time:

A)an order spends waiting for processing at a work center.
B)an order spends being processed at a work center.
C)an order spends moving from one work center to another.
D)to complete an order,including time spent in processing and in waiting.
E)none of the above

Question 68

Which critical ratio value implies that a job is already late?

A)more than 100
B)1
C)less than 1
D)10
E)3.4

Question 69

Which of the following is a limitation of rules-based dispatching systems?

A)Rules need to be revised to adjust to changes in orders,product mix,and so forth.
B)Rules may not recognize idle resources.
C)Rules may not recognize bottleneck resources
D)Rules may not be able to prioritize two jobs with identical due dates.
E)All of the above are limitations.

Question 70

Five jobs are waiting for processing through two work centers.Their processing time (in minutes)at each work center is contained in the table below.Each job requires work center Alpha before work center Beta.According to Johnson's rule,which job should be scheduled first in the sequence?

A)R
B)S
C)T
D)U
E)V

Question 71

What does the use of the shortest processing time sequencing rule generally produce?

A)maximum average lateness
B)maximum utilization
C)maximum effectiveness
D)minimum average flow time
E)B and D

Question 72

Which of the following dispatching rules tends to minimize job flow time?

A)FCFS: first come,first served
B)SPT: shortest processing time
C)EDD: earliest due date
D)LPT: longest processing time
E)FCLS: first come,last served

Question 73

What is the priority rule that sequences jobs using the smallest ratio of due date from today to processing time?

A)critical ratio
B)earliest due date
C)first come,first served
D)longest processing time
E)shortest processing time

Question 74

________ determine the sequence of jobs in process-oriented facilities.

Question 75

Eight jobs have been sequenced at a single work center.Total processing time for the eight jobs is 34 hours,and total flow time for the sequence is 85 hours.For this schedule,utilization is ________ and the average number of jobs in the system is ________.

A)100 percent;10.625
B)low;.0941
C)0.400 or 40 percent;2.5
D)0.235 or 23.5 percent;4.25
E)maximized;minimized

Question 76

Five jobs are waiting for processing through two work centers.Their processing time (in minutes)at each work center is contained in the table below.Each job requires work center Sigma before work center Delta.According to Johnson's rule,what sequence of jobs will minimize the completion time for all jobs?

A)R-S-T-U-V
B)S-V-T-R-U
C)S-U-T-V-R
D)V-R-U-S-T
E)R-V-T-S-U

Question 77

Sequencing (or dispatching):

A)assigns dates to specific jobs or operations steps.
B)assigns jobs to work centers.
C)specifies the order in which jobs should be done at each center.
D)assigns workers to jobs.
E)assigns workers to machines.

Question 78

________ determines the order in which jobs should be done at each work center.

Question 79

Five welding jobs are waiting to be processed.Their processing times and due dates are given below.Using the critical ratio dispatching rule,in which order should the jobs be processed? All dates are specified as days from today.

A)B,D,A,E,C
B)C,D,A,B,E
C)C,E,A,D,B
D)E,B,A,D,C
E)B,D,A,C,E

Question 80

Average completion time for a schedule sequence at a work center is the ratio of:

A)total processing time to the number of jobs.
B)total flow time to total processing time.
C)total flow time to the number of jobs.
D)total processing time plus total late time to the number of jobs.
E)total flow time plus total late time to the number of jobs.