Q&A Hero

Q: What is the primary disadvantage of the shortest processing time dispatch rule? Is this a problem if there can be no new jobs arriving after the sequence is set?

Q: In retail outlets, customers are usually processed on a first come, first served basis. Why? Is the express lane in the supermarket an exception? Craft a sequencing rule to explain express lane behavior.

Q: What does Johnson's rule do?

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

Q: Identify the disadvantages of the Gantt load chart.

Q: What is the assignment method?

Q: What are the options available to operations personnel to manage facility work flow?

Q: What is input-output control?

Q: Identify the types of planning files used in scheduling decisions. Which are used in manual systems, and which are used in automated systems?

Q: How does short-term scheduling vary among the different process choices? Specifically, compare short-term scheduling at process-oriented, work cells, repetitive, and product-focused facilities.

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

Q: What makes short-term scheduling of strategic importance?

Q: 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.

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

Q: __________ uses computerized short-term scheduling to overcome the disadvantages of rule-based systems by providing the user with interactive computing and graphical output.

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

Q: The priority rule that appears fair to customers in service systems is __________.

Q: __________ determine the sequence of jobs in process-oriented facilities.

Q: __________ determines the order in which jobs should be done at each work center.

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

Q: __________ are used to schedule resources and allocate time.

Q: __________ is an input-output control system that uses cards to manage the amount of work in a work center.

Q: __________ is the assignment of jobs to work or processing centers.

Q: Because facility capacity, set-up time, and run time are usually known, scheduling is often straightforward in __________ facilities.

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

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

Q: Which of the following is true regarding services scheduling? A) The critical ratio sequencing rule is widely used for fairness to customers. B) The emphasis is on staffing levels, not materials. C) Reservations and appointments are often used to manipulate the supply of services. D) Labor use can be intensive, and labor demand is usually stable. E) All of the above are true.

Q: Which of the following is not tracked by scheduling optimization systems used in retail stores? A) cars parked in the parking lot B) individual store sales C) transactions D) units sold E) customer traffic

Q: An appliance manufacturer assembles icemakers in large batches. The operations manager would like to significantly reduce the batch size. What would you suggest? A) Use the SPT rule. B) Use forward scheduling. C) Use Gantt charts. D) Use finite scheduling. E) Develop level material use schedules.

Q: Which of the following statements regarding finite capacity scheduling (FCS) is false? A) Finite capacity scheduling is well suited for dynamic scheduling environments. B) Finite capacity scheduling overcomes the disadvantages of systems based exclusively on rules. C) Finite capacity scheduling is very powerful, but does not allow for rapid changes. D) Finite capacity scheduling often gets its data from the output of an MRP system. E) None; all of the above are true.

Q: Which of the following statements regarding finite capacity scheduling (FCS) is false? A) Finite capacity scheduling allows delivery needs to be balanced against efficiency. B) Finite capacity scheduling overcomes the disadvantages of systems based exclusively on rules. C) Finite capacity scheduling allows virtually instantaneous change by operators. D) Finite capacity scheduling software formalizes the same data needed in any manual system. E) None; all of the above are true.

Q: 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

Q: 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? Job Alpha Beta R 20 10 S 25 35 T 50 20 U 15 35 V 55 75 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

Q: 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.

Q: 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? Job Sigma Delta R 40 10 S 25 30 T 50 20 U 35 35 V 55 15 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

Q: 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? Job Alpha Beta R 20 10 S 25 35 T 50 20 U 15 35 V 55 75 A) R B) S C) T D) U E) V

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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.

Q: 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

Q: 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

Q: 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. Job Processing Time (days) Job due date (days) A 4 7 B 2 4 C 8 11 D 3 5 E 5 11 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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? Job Processing Time (days) Job due date (days) A 4 7 B 2 4 C 8 11 D 3 5 E 5 8 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

Q: 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

Q: 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? Job Processing Time (days) Job due date (days) A 4 7 B 7 4 C 8 11 D 3 5 E 5 8 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

Q: 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

Q: 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

Q: 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 Machine A Machine B Machine C Job 1 11 14 6 Job 2 8 10 11 Job 3 9 12 7 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

Q: 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.

Q: 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.

Q: 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

Q: 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

Q: 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

Q: EDD stands for A) earliest due date B) earliest design date C) earliest detrimental date D) earliest decision date E) none of the above

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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.

Q: 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.

Q: 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.

Q: 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.

Q: 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

Q: 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? Job Processing Time (days) Job due date (days) A 20 180 B 30 200 C 10 175 D 16 230 E 18 210 A) 47.6 days B) 60.2 days C) 94.0 days D) 2.5 days E) 238.0 days

Q: 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? Job Processing Time (days) Job due date (days) A 20 180 B 30 200 C 10 175 D 16 230 E 18 210 A) 0.0 days B) 24.0 days C) 7.4 days D) 10.0 days E) 11.6 days

Q: 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

Q: 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

Q: 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