12:52 ull e elearning.yu.edu.jo b. Answer these questions: (1) What is the shortest cycle time that will permit use of only two workstations? Is this cycle feasible? Identify the tasks you would assign to cach station. mine the percentage of idle time that would result if two stations were used. 49 of 54 is the daily output under this arrangement? mine the output rate that would be associated with the maximum cycle time. dirgham@xd.ae 290 Chapter Six Process Selection and Facility Layout 5. As part of a major plant renovation project, the industrial engineering department has been asked to balance a revised assembly operation to achieve an output of 240 units per eight-hour day. Task times and precedence relationships are as follows: Duration (minutes) Immediate Task (Predecessor) 0.2 0.4 0.2 0.4 1.2 1.2 1.0 e, f Do each of the following: a. Draw the precedence diagram. b. Determine the minimum cycle time, the maximum cycle time, and the calculated cycle time. c. Determine the minimum number of stations needed. d. Assign tasks to workstations on the basis of most following tasks. Use shortest processing time as a ticbreaker. If ties still exist, assume indifference in choice. e. Compute the percentage of idle time for the assignment in part d. 6. Twelve tasks, with times and precedence requirements as shown in the following table, are to be assigned to workstations using a cycle time of 1.5 minutes. Two heuristic rules will be tried: (1) greatest positional weight, and (2) most following tasks. In each case, the tiebreaker will be shortest processing time. Length (minutes) Immediate Task Predecessor 0.1 0.2 0.9 b. 0.6 0.1 0.2 0.4 0.1 0.2 0.7 0.3 0.2 a. Draw the precedence diagram for this line. b. Assign tasks to stations under each of the two rules. c. Compute the percentage of idle time for each rule. 7. For the given set of tasks, do the following: a. Develop the precedence diagram. b. Determine the minimum cycle time and then calculate the cycle time for a desired output 500 units in a seven-hour day. Why might a manager use a cycle time of 50 seconds? c. Determine the minimum number of workstations for output of 500 units per day. dirgham@xd.ae Chapter Six Process Selection and Facility Layout 291 d. Balance the line using the greatest positional weight heuristic. Break ties with the most follow- ing tasks heuristic. Use a cycle time of 50 seconds. e. Calculate the percentage idle time for the line. Task Time (seconds) Immediate Predecessor Task ->

12:52 ull e elearning.yu.edu.jo b. Answer these questions: (1) What is the shortest cycle time that will permit use of only two workstations? Is this cycle feasible? Identify the tasks you would assign to cach station. mine the percentage of idle time that would result if two stations were used. 49 of 54 is the daily output under this arrangement? mine the output rate that would be associated with the maximum cycle time. dirgham@xd.ae 290 Chapter Six Process Selection and Facility Layout 5. As part of a major plant renovation project, the industrial engineering department has been asked to balance a revised assembly operation to achieve an output of 240 units per eight-hour day. Task times and precedence relationships are as follows: Duration (minutes) Immediate Task (Predecessor) 0.2 0.4 0.2 0.4 1.2 1.2 1.0 e, f Do each of the following: a. Draw the precedence diagram. b. Determine the minimum cycle time, the maximum cycle time, and the calculated cycle time. c. Determine the minimum number of stations needed. d. Assign tasks to workstations on the basis of most following tasks. Use shortest processing time as a ticbreaker. If ties still exist, assume indifference in choice. e. Compute the percentage of idle time for the assignment in part d. 6. Twelve tasks, with times and precedence requirements as shown in the following table, are to be assigned to workstations using a cycle time of 1.5 minutes. Two heuristic rules will be tried: (1) greatest positional weight, and (2) most following tasks. In each case, the tiebreaker will be shortest processing time. Length (minutes) Immediate Task Predecessor 0.1 0.2 0.9 b. 0.6 0.1 0.2 0.4 0.1 0.2 0.7 0.3 0.2 a. Draw the precedence diagram for this line. b. Assign tasks to stations under each of the two rules. c. Compute the percentage of idle time for each rule. 7. For the given set of tasks, do the following: a. Develop the precedence diagram. b. Determine the minimum cycle time and then calculate the cycle time for a desired output 500 units in a seven-hour day. Why might a manager use a cycle time of 50 seconds? c. Determine the minimum number of workstations for output of 500 units per day. dirgham@xd.ae Chapter Six Process Selection and Facility Layout 291 d. Balance the line using the greatest positional weight heuristic. Break ties with the most follow- ing tasks heuristic. Use a cycle time of 50 seconds. e. Calculate the percentage idle time for the line. Task Time (seconds) Immediate Predecessor Task ->

Practical Management Science

6th Edition

ISBN:9781337406659

Author:WINSTON, Wayne L.

Publisher:WINSTON, Wayne L.

Chapter12: Queueing Models

Section: Chapter Questions

Problem 59P

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