Questions and Answers of Principles Of Operations

Describe the differences among product, process, and group technology layouts.Describe the circumstances in which each type of layout is appropriate.
Suggest a layout for the Meat Me fast-food restaurant, with the relationship chart shown in Figure 11–2. Assume that the facility is 50 feet square and half the restaurant will be for customer
Consider the example of the machine shop with the from-to charts given in Figures 11–3 through 11–5. Based on the results of Figure 11–5, in what ways might the current layout be improved?
The routing for these products and their forecasted production rates are Forecasted Production Product Routing (units/week)1 A–B–C–D–E 200 2 A–D–E 900 3 A–B–C–E 400 4 A–C–D–E
Four products are produced in the facility described in Problem
A manufacturing facility consists of five departments: A, B, C, D, and E. At the current time, the facility is laid out as in Figure 11–10. Develop a from-to distance chart for this layout.
For each of the eight objectives of a layout study listed in Section 11.1, give examples of situations in which that objective would be important and examples in which it would be unimportant.
Consider the following project time and cost data:Immediate Normal Expedited Normal Expedited Activity Predecessors Time Time Cost Cost A — 6 6 $ 200 $ 200 B A 10 4 600 1,000 C A 12 9 625 1,000 D B
Based on past experience, the director is not very confident about the time estimates for some of the activities.The director’s estimates for the minimum, most likely, and maximum times for these
Consider the filming of the scene described in Problem
A guidance and detection system is being built as part of a large defense project.The detection portion consists of radar and sonar subsystems. Separate equipment is required for each of the
A scene is being shot for a film. A total of 11 distinct activities have been identified for the filming. First, the script must be verified for continuity, the set erected and decorated, and the
Two brothers have purchased a small lot, in the center of town, where they intend to build a gas station. The station will have two pumps, a service area for water and tire maintenance, and a main
Consider the project network pictured in Figure 10–22. Activity times, measured in days, are shown in parentheses next to each activity label.a. Determine the earliest and the latest starting and
The tasks require both welders and pipe fitters. The requirements are Number of Number of Activity Welders Required Pipe Fitters Required A 6 10 B 3 15 C 8 8 D 0 20 E 10 6 F 10 9 G 4 14a. Determine
Consider the project described in Problem
Three machines, M1, M2, and M3, are required to complete the project. The requirements for each activity are as follows:Activity Machines Required A M1, M2 B M1, M3 C M2 D M1, M2 E M2 F M1, M3 G M2,
Consider the project described in Problem
For the case problem discussed in this chapter (Example 10.10), suppose that the requirements for RAM and permanent storage are given by RAM Required Permanent Storage Activity (GB) Required (GB)A 0
Suppose that the activity times are random variables with a constant coefficient of variation of 0.2. (The coefficient of variation is the ratio .) Assume that the times given in Problem 3 are the
Consider the project described in Problem
Consider the project network pictured in Figure 10–18. Assume that the times attached to each node are the means and the variances of the project completion times, respectively.a. Identify all
Consider the following PERT time estimates:Immediate Activity Predecessors a m b A — 2 5 9 B A 1 6 8 C A 3 5 12 D B 2 4 12 E B, C 4 6 8 F B 6 7 8 G D, E 1 2 6 H F, G 4 6 16a. Draw a network for
With reference to Example 10.4 and Figure 10–5,what is the conditional probability that the project is completed by the end of week 25, given that activitiesA through H (node 7) are completed at
Referring to Example 10.4 and Figure 10–5, what is the probability that node 6 (i.e., the completion of activities A, C, E, and F) is reached before 12 weeks have elapsed?
Solve Problem 10 by linear programming.
Solve Problem 8 by linear programming.
Solve Problem 6 by linear programming.
Formulate Problem 5 as a linear program.
Solve Problem 4 by linear programming.
Solve Problem 3 by linear programming.
Suppose that the normal and the expedited costs and times are as given in the following table.Normal Expedited Normal Expedited Activity Time Time Cost Cost A 32 26 $ 200 $ 500 B 21 20 300 375 C 30
Consider Problem
Discuss the assumption that the cost–time curve is linear. What shape might be more realistic in practice?
Consider the project described in Problem 3 with the normal and the expedited costs and times given in the following table.Immediate Normal Expedited Normal Expedited Activity Predecessor Time Time
Consider Example 10.5 presented in this section in which the two programmers are to develop a commercial software package.a. What is the minimum project time and the total direct cost of completing
A project consists of seven activities. The precedence relationships are given in the following table.Time Immediate Activity (days) Predecessors A 32 B 21 C 30 D 45 A E 26 A, B F 28 C G 20 E, Fa.
Consider the network pictured in Figure 10–9.a. Determine the immediate predecessors of each activity from the network representation.(Hint: Be certain that you consider only immediate
For the project network pictured in Figure 10–8,a. List the immediate predecessors of each activity.b. Try to determine the critical path by enumerating all paths from node 1 to node 10.c. Compute
A project consisting of eight activities satisfies the following precedence constraints:Time Immediate Activity (weeks) Predecessors A 3 B 5 A C 1 A D 4 B, C E 3 B F 3 E, D G 2 F H 4 E, Da. Construct
For Example 10.4, suppose that the programmers choose not to obtain additional help to complete the project; that is, Bonner will code the modules without outside assistance.a. In what way will this
Answer the following questions for Example 10.4.a. What event is represented by node 6 in Figure 10–5?b. What group of activities will have to be completed by week 16 in order to guarantee that the
a. Solve Problem 45(a) assuming EDD sequencing. In this case one sorts on the due date column.b. Solve Problem 45(b) assuming EDD sequencing.c. Solve Problem 45(c) assuming EDD sequencing.
a. Solve Problem 45(a) assuming SPT sequencing. To do this you may use the spreadsheet developed in Problem 45 and simply sort the data in the first three columns, using column 2 (the processing
Column 2 should be the processing times to be inputted by the user, and column 3 the due dates also inputted by the user. Column 4should be the tardiness and column 5 the flow time. Develop the logic
Develop a template that computes several measures of performance for firstcome, first-served job sequencing. Allow for up to 20 jobs so that column 1 holds the numbers 1, 2, . . . ,
Set in grips and balance 12 6, 7a. Draw a network to represent the assembly operation.b. What is the minimum cycle time that can be considered? Determine the balance that results from the ranked
Place glue on other end of shaft 3 1
Place and secure connecting pin 3 5
Connect wood to shaft 6 1, 2, 4
Imprint number 4 3
Polish club head 6
Grind the shaft end 14
Polish shaft 12
The Southeastern Sports Company produces golf clubs on an assembly line in its plant in Marietta, Georgia. The final assembly of the woods requires the eight operations given in the following table.T
Suppose in Problem 42 that additional constraints arise from the fact that certain tasks cannot be performed at the same station. In particular suppose that the tasks are zoned in the following
The assembly of a transistorized clock radio requires a total of 11 tasks. The task times and predecessor relationships are given in the following table.I mmediate Task T ime (seconds) Predecessors 1
Five Hong Kong tailors—Simon, Pat, Choon, Paul, and Wu—must complete alterations on a suit for the duke and a dress for the duchess as quickly as possible.On the dress, Choon must first spend 45
An independent accountant is planning to prepare tax returns for six of her clients.Prior to her actually preparing each return, her secretary checks the client’s file to be sure all the necessary
A leatherworks factory has two punch presses for punching holes in the various leather goods produced in the factory prior to sewing. Suppose that 12 different jobs must be processed on one or the
William Beebe owns a small shoe store. He has 10 pairs of shoes that require resoling and polishing. He has a machine that can resole one pair of shoes at a time, and the time required for the
Irving Bonner, an independent computer programming consultant, has contracted to complete eight computer programming jobs. Some jobs must be completed in a certain sequence because they involve
Suppose that if vanilla or strawberry is produced after chocolate or peanut fudge, an extra day of cleaning is required. For that reason they decide that the vanilla and strawberry will be produced
Consider Barbara and Jenny’s Ice Cream Company, mentioned in Problem
Barbara and Jenny’s Ice Cream Company produces four different flavors of ice cream: vanilla, chocolate, strawberry, and peanut fudge. Each batch of ice cream is produced in the same large vat,
Determine the sequence in which patients should be treated in order to minimize the weighted value of the mean flow time.
Consider the situation of the emergency room mentioned in Problem
What sequencing of the jobs minimizes thea. Mean flow time?b. Maximum lateness?c. Number of tardy jobs?
Consider Mike’s Auto Body Shop mentioned in Problem
Six patients are waiting in a hospital emergency room to receive care for various complaints, ranging from a sprained ankle to a gunshot wound. The patients are numbered in the sequence that they
For each of the problems listed, indicate precisely what or who would correspond to jobs and who or what would correspond to machines. In each case discuss what objectives might be appropriate and
Mike’s Auto Body Shop has five cars waiting to be repaired. The shop is quite small, so only one car can be repaired at a time. The number of days required to repair each car and the promised date
Consider the assembly line balancing problem represented by the network in Figure 9–17. The performance times are shown above the nodes.a. Determine a balance for C 15.b. Determine a balance for
For the data given in Problem 27, determine by experimentation the minimum cycle time for a three-station balance.
Aproduction facility assembles inexpensive telephones on a production line.The assembly requires 15 tasks with precedence relationships and activity times as shown in Figure 9–16. The activity
Consider the example of Noname computers presented in this section.a. What is the minimum cycle time that is possible? What is the minimum number of stations that would theoretically be required to
A critical resource in a manufacturing operation experiences a very high traffic intensity during the shop’s busiest periods. During these periods the arrival rate is approximately 57 jobs per
Consider the computer system of Problem 23.a. Compute the variance of the flow times assuming FCFS, LCFS, and random selection disciplines.b. Using a normal approximation of the flow time
A computer system queues up batch jobs and processes them on an FCFS basis.Between 2 and 5 P.M., jobs arrive at an average rate of 30 per hour and require an average of 1.2 minutes of computer time.
Five sorority sisters plan to attend a social function. Each requires hair styling and fitting for a gown. Assume that the times required are independent exponentially distributed random variables
Solve Problem 13 assuming that the times required by John and Marsha are exponentially distributed random variables with expected times given in Problem 13.
In what sequence should the ships be unloaded in order to minimize the expected weighted time?
Six ships are docked in a harbor awaiting unloading. The times required to unload the ships are random variables with respective means of 0.6, 1.2, 2.5, 3.5, 0.4, and 1.8 hours. The ships are given a
A computer center has two identical computers for batch processing. The computers are used as parallel processors. Job times are estimated by the user, but experience has shown that an exponential
Consider Example 9.2 in Section 9.5 on determining the optimal sequence to land the planes. Suppose that the landing times are random variables with standard deviation equal to one-third of the mean
Peter Minn is planning to go to the Department of Motor Vehicles to have his driver’s license renewed. His friend, Patricia, who is accompanying him, is applying for a new license. In both cases
Two jobs must be processed through four machines in the same order. The processing times in the required sequence are Job 1 Job 2 Machine Time Machine Time A 5 A 2 B 4 B 4 C 6 C 3 D 3 D 5 Determine
Mary and Marcia Brown are two sisters currently attending university together.Each requires advising in five subjects: history, English, mathematics, science, and religion. They estimate that the
The following four jobs must be processed through a three-machine flow shop.Machine Job A B C 1 4 2 6 2 2 3 7 3 6 5 6 4 3 4 8 Find the optimal sequencing of the jobs in order to minimize the
Two law students, John and Marsha, are planning an all-nighter to prepare for their law boards the following day. Between them they have one set of materials in the following five subjects:
Suppose that 12 jobs must be processed through six machines. If the jobs may be processed in any order, how many different possible schedules are there? If you were to run a computer program that
Consider Example 9.6, illustrating the use of Johnson’s algorithm for three machines. List all optimal solutions for this example.
Seven jobs are to be processed through a single machine. The processing times and due dates are given here.Job 1 2 3 4 5 6 7 Processing time 3 6 8 4 2 1 7 Due date 4 8 12 15 11 25 21 Determine the
Jane Reed bakes breads and cakes in her home for parties and other affairs on a contract basis. Jane has only one oven for baking. One particular Monday morning she finds that she has agreed to
Eight jobs are to be processed through a single machine. The processing times and due dates are given here.Job 1 2 3 4 5 6 7 8 Processing time 2 3 2 1 4 3 2 2 Due date 5 4 13 6 12 10 15 19
On May 1, a lazy MBA student suddenly realizes that he has done nothing on seven different homework assignments and projects that are due in various courses. He estimates the time required to
Determine the sequence that the trucks should be unloaded in order to minimizea. Mean flow time.b. Maximum lateness.c. Number of tardy jobs.
Consider the information given in Problem
Five jobs must be scheduled for batch processing on a mainframe computer system.The processing times and the promised times for each of the jobs are listed here.Job 1 2 3 4 5 Processing time 40 min
Four trucks, 1, 2, 3, and 4, are waiting on a loading dock at XYZ Company that has only a single service bay. The trucks are labeled in the order that they arrived at the dock. Assume the current

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