Comm 399: Logistics and Operations Management Problem Set 1
University of British Columbia Sauder School of Business COMM 399: Logistics and Operations Management
Problem Set 1
1. Solution: (a) Some ideas that you can expand on: • • • • Organizational barriers Business culture undervalues operations Top managers often uninterested in operations Lack of “ownership” of operations
(b) Some ideas that you can expand on: • Identify and break constraints • Make the special case the norm • Rethink critical dimensions of work
(c) Yes, even though it may seem that operational innovations can be easily imitated by competitors. There could be many reasons why this could be so, for example: • Organizational inertia • Denial of competitor superiority 2. Solution: (a) Inventory build-up diagram: First, recognize that the input and output rates changes at 8:30am, 9am, 9:30am and 10:30am (as well as at the end when all customers are served). • At the beginning (8:30am): There is no customer in the system. So the “inventory” is 0. • Between 8:30am and 9am: Customers arrive at the rate of 30/hr. Customers leave at the rate of 0/hr. Thus the line becomes longer at the rate of 30/hr. Draw a line with the slope of 30/hr in this interval. (Since the inventory was 0 at 8:30, the inventory will become 0 + 1 · 30 = 15 at 9am.) 2 • Between 9am and 9:30am: Customers arrive at the rate of 30/hr. Customers leave at the rate of 20/hr. Thus the line becomes longer at the rate of 10/hr. Draw a line with the slope of 10/hr. (Since the inventory was 15 at 9am, the inventory will become 15 + 1 · 10 = 20 at 9:30am.) 2 • Between 9:30am and 10:30am: Since customers arrive at the rate of 15/hr and leave at the rate of 20/hr, the line becomes shorter at the rate of 5/hr. Draw a line with the slope of −5/hr. Then, the inventory will become 20 + (1)(−5) = 15 at 10:30am. • 10:30am onwards: Since customers arrive at the rate of 0/hr and leave at the rate of 20/hr, the line becomes shorter at the rate of −20/hr. Draw a line with the slope of −20/hr. Since
Problem Set 1
1. Solution: (a) Some ideas that you can expand on: • • • • Organizational barriers Business culture undervalues operations Top managers often uninterested in operations Lack of “ownership” of operations
(b) Some ideas that you can expand on: • Identify and break constraints • Make the special case the norm • Rethink critical dimensions of work
(c) Yes, even though it may seem that operational innovations can be easily imitated by competitors. There could be many reasons why this could be so, for example: • Organizational inertia • Denial of competitor superiority 2. Solution: (a) Inventory build-up diagram: First, recognize that the input and output rates changes at 8:30am, 9am, 9:30am and 10:30am (as well as at the end when all customers are served). • At the beginning (8:30am): There is no customer in the system. So the “inventory” is 0. • Between 8:30am and 9am: Customers arrive at the rate of 30/hr. Customers leave at the rate of 0/hr. Thus the line becomes longer at the rate of 30/hr. Draw a line with the slope of 30/hr in this interval. (Since the inventory was 0 at 8:30, the inventory will become 0 + 1 · 30 = 15 at 9am.) 2 • Between 9am and 9:30am: Customers arrive at the rate of 30/hr. Customers leave at the rate of 20/hr. Thus the line becomes longer at the rate of 10/hr. Draw a line with the slope of 10/hr. (Since the inventory was 15 at 9am, the inventory will become 15 + 1 · 10 = 20 at 9:30am.) 2 • Between 9:30am and 10:30am: Since customers arrive at the rate of 15/hr and leave at the rate of 20/hr, the line becomes shorter at the rate of 5/hr. Draw a line with the slope of −5/hr. Then, the inventory will become 20 + (1)(−5) = 15 at 10:30am. • 10:30am onwards: Since customers arrive at the rate of 0/hr and leave at the rate of 20/hr, the line becomes shorter at the rate of −20/hr. Draw a line with the slope of −20/hr. Since