- Jane Smith has been hired by Wolverine Airlines to redesign their terminal counter operations, where customers check in (check baggage, receive boarding passes, and change flight details if necessary). The airline is very sensitive to their customers’ time spent waiting for service and being served; many customers dislike waiting in these queues, are anxious about missing their flights, etc. Wolverine currently has three counters, each staffed by a single employee, and a single FCFS queue for all customers to join. Seeing how Wolverine currently configures their queues, Jane thinks that they have got it all wrong. Jane redesigns the queues so that there is a dedicated queue and a dedicated server for each of the customer classes (economy, business, and first class). No customers cross between servers. Each of the three serving employees takes an average of 3 minutes to check in customers. Assume arrivals follow a Poisson process and service time is exponentially distributed. Without any knowledge on the arrival rates of Economy class (E), Business Class (B), or First Class (F) passengers, can you argue about which system design is better from both a system and an arbitrary customer perspective? Provide a comprehensive answer by relating to the pertinent performance measure of interest.
Braden works alone at a very popular dog salon called “Pup-Style” which always has customers waiting for service. Each customer requests Braden’s signature “wash, dry, and style” package for their pet. It takes Braden exactly 10 minutes to wash and dry the pet and exactly 12 minutes to style. For all parts of this question, define the “process” for a single customer to begin once the customer hands over the pet for a wash and ends once the style is complete. Assume the process is operating at capacity.
a. What is the capacity of the process (in customers per minute)?
b. Suppose Braden gets tired of working alone and hires another pet stylist, Helmut, to help. Since Braden doesn’t yet have confidence in Helmut’s styling abilities, he is hired to handle washing and drying. Helmut can wash and dry the pet in 12 minutes. Hand-off times are negligible. What is the capacity of the process now (customers/minute)?
c. Within a short period, Helmut becomes very efficient and can now wash and dry a pet in 8 minutes (faster than Braden). Braden still takes 12 minutes to style a pet. What is the capacity of the process now (customers/minute)?
d. After a trial period, Braden is happy with Helmut’s performance and decides both of them should take their own customers (that is, each will alone handle washing, drying and styling for their respective customers). Customers express no preference between the two stylists and simply choose the next one available. Assume it takes Helmut exactly 20 minutes to wash, dry and style a pet. What is the capacity of the process now?
e. Assuming Braden and Helmut are working at their full capacity, what is the average cycle time of a customer through the process (in minutes)?
BLANCHARD CASE STUDY 55%
Read Case study below to answer questions
- What is wrong with the way that the EOQ and ROP quantities have been determined for each of the five items mentioned in the case? Justify your answer by considering all the relevant possible angles (e.g., model choice, demand data, cost data, etc.) 25%
- Assuming that an EOQ/ROP system is an appropriate way to run this system, how would you correct the EOQ/ROP quantities for the five items? (also use the table format to explain) 10%
- What are the advantages and/or disadvantages of your (updated) EOQ/ROP system, and the actual system used for scheduling bottling runs at Blanchard? Which system do you prefer? Again, justify your answer by considering all the relevant possible angles. 15%
- What should Hank Hatch recommend to his boss, Toby Tyler? What improvements can be made? 5%
Sample Solution
