Deck 15: Short-Term Scheduling

Question 1

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

Answer 1

False

Question 2

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

Answer 2

True

Question 3

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

Answer 3

False

Question 4

One criterion for developing effective schedules is minimizing completion time.

Question 5

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

Question 6

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

Question 7

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

Question 8

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

Question 9

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

Question 10

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.

Question 11

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

Question 12

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 13

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

Question 14

Finite capacity scheduling allows virtually instantaneous changes by operators, which is the technique's primary advantage over rule-based scheduling.

Question 15

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

Question 16

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 17

The word "finite" in finite capacity scheduling refers to the use of finite or limited capacity rather than unlimited capacity.

Question 18

In services, the scheduling emphasis is usually on staffing levels, not materials.

Question 19

Scheduling optimization systems used in retail stores typically track customer traffic in 4-hour time increments.

Question 20

The first step in level material use is to combine orders into a few large batches in order to utilize economies of scale.

Question 21

Which file contains important information regarding an item's flow through the shop?

A) item master file
B) work-center master file
C) control files
D) routing file
E) None of the above provides information regarding an item's flow through the shop.

Question 22

The jobs listed below needed to be completed. Assume that it is now day 140. If the jobs are sequenced according to 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 23

The jobs listed below needed to be completed. Assume that it is now day 140. If the jobs are sequenced according to 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 24

Which of the following best describes the strategic importance of short-term scheduling?

A) Effective scheduling, through lower costs, faster delivery, and dependable delivery, can provide a competitive advantage.
B) Effective scheduling is a tactical tool for increasing demand to meet production.
C) Forward scheduling looks to future demand levels in order to increase customer satisfaction.
D) Aggregate planning is a tactical action, but short-term scheduling is strategic because of its immense impact on costs.
E) Short-term scheduling matches capacity to demand during the short term, three to eighteen months into the future.

Question 25

Which of the following is not a key benefit from effective scheduling?

A) lower cost
B) faster delivery
C) dependable delivery
D) quality
E) A and D

Question 26

Because of the significance of labor in the scheduling of services, behavioral and social issues, wage and hour law, and union contracts all complicate the scheduling process.

Question 27

In manufacturing scheduling, physical inventories of goods can buffer variations in demand, but service scheduling normally lacks that buffer because services are generally consumed at the same time they are delivered.

Question 28

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 29

The correct sequence from longest to smallest duration scheduling is

A) capacity planning, aggregate planning, master schedule, short-term schedule
B) aggregate planning, capacity planning, master schedule, short-term schedule
C) master schedule, capacity planning, aggregate planning, short-term schedule
D) master schedule, aggregate planning, capacity planning, short-term schedule
E) None of the above is correct

Question 30

The sequence of decisions that affect scheduling is

A) short term→intermediate term→long term
B) capacity planning→aggregate planning→master schedule→short-term schedules
C) strategic decisions→tactical decisions→operational decisions
D) forward decisions→current decisions→backward decisions
E) none of the above

Question 31

The objective of scheduling is to

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

Question 32

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 33

Forward scheduling

A) begins with a delivery date, then offsets each operation one at a time, in reverse order
B) is well suited where the supplier is usually able to meet precise delivery dates
C) tends to minimize work-in-process inventory
D) assumes that procurement of material and operations start as soon as requirements are known
E) produces a schedule only if it meets the due date

Question 34

Scheduling is rather straightforward in product-focused facilities because

A) kanban automates the scheduling of the assembly line
B) demand is reasonably stable, and capacities, set-up times, and run times are generally known
C) assembly line balancing assures the highest possible production efficiency
D) finite capacity scheduling has made MRP much more realistic
E) All of the above are true.

Question 35

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 36

The three components that can lead to competitive advantage through effective scheduling are

A) quality, dispatching, and MRP
B) ABC analysis, MRP, and loading
C) the item master file, the routing file, and the work-center master file
D) lower costs, faster delivery, and dependable delivery
E) Gantt charts, Johnson's rule and the Pareto principle

Question 37

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 38

Which scheduling technique should be employed when due dates are important for a job order?

A) forward scheduling
B) loading
C) dispatching
D) backward scheduling
E) master scheduling

Question 39

Some firms have developed arrangements to literally "swap" employees with each other during their respective peak demand times.

Question 40

Which of these is not part of the planning files of a production planning and control system?

A) a progress file
B) a work-center master file
C) an item master file
D) a routing file
E) All of the above are all part of the planning files.

Question 41

A scheduling technique used to achieve optimum, one-to-one matching of tasks and resources is

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

Question 42

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 43

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

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

Question 44

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 45

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) Loading

Question 46

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 47

EDD stands for

A) earliest due date
B) earliest design date
C) earliest detrimental date
D) earliest decision date
E) none of the above

Question 48

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

A) ABCD
B) DCBA
C) DACB
D) DABC
E) none of the above

Question 49

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 is

A) the assignment method
B) backward scheduling
C) forward scheduling
D) constant work-in-process or ConWIP
E) level material use

Question 50

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

A) worker A- job 1 worker B- job 2
B) worker A- job 2 worker B- 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 51

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, D, B

Question 52

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 53

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 54

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 55

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

A) a Gantt load chart
B) the assignment method
C) a Gantt schedule chart
D) Johnson's rule
E) none of the above

Question 56

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 57

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

Question 58

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 given information

Question 59

Which of the following files tracks work order progress?

A) work-center master files
B) routing files
C) item master files
D) control files
E) None of the above tracks work order progress.

Question 60

The production database containing information about each of the components that a firm produces or purchases is the

A) routing file
B) work-center master file
C) control file
D) item master file
E) none of the above

Question 61

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

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

Question 62

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 63

Which of the following are limitations 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 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) none of the above

Question 65

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) none of the above

Question 66

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 67

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 68

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 69

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 average 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 70

Conventional MRP uses time buckets that do not recognize capacity limits, and in fact ignores capacity issues. A more realistic scheduling system that includes work center capacities and other resource availabilities is

A) aggregate planning
B) the master production schedule
C) finite capacity scheduling
D) the assignment method
E) level material use

Question 71

Use of the shortest processing time sequencing rule generally results in

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

Question 72

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

A) more than 100
B) 1
C) less than 1
D) 10
E) none of the above

Question 73

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) none of the above

Question 74

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

A) FCFS is easy to update.
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 75

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) none of the above

Question 76

The most appropriate sequencing rule to use if the goal is to dynamically track the progress of jobs and establish relative priority on a common basis is

A) shortest processing time
B) earliest due date
C) critical ratio
D) longest processing time
E) Johnson's rule

Question 77

Which of the following dispatching rules is typically the best technique for taking first those jobs with the most urgent needs?

A) shortest processing time
B) critical ratio
C) earliest due date
D) longest processing time
E) none of the above

Question 78

A recent advance in short-term scheduling that makes use of expert systems and simulation in solving dynamic scheduling problems is

A) forward scheduling
B) backward scheduling
C) infinite scheduling
D) finite capacity scheduling
E) progressive scheduling

Question 79

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 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