Improvement of Queuing in Cong Sao Dessert

KONG Lingtao 20144929 KUANG Jiafei 20170435

BU Xuezhu 20170459 BAI Lu 20171051

PAN Xin 20145040

Introduction

Cong Sao Dessert Problem-Long Queue Queuing Model Selection

Cong Sao Dessert

Cong Sao Dessert is a popular chain dessert shop in Hong Kong.

Capacity of Seats 68 Cooks 3 Waitress 5 Cashier 1 Salary of a Cook HK$15000 Per Month

Salary of a Waitress HK$12000 Per Month Average time for dessert preparation 6 minutes Per Order No. of total orders in rush hour 25 Per Hour No. of take-out orders in rush hour 10 Per Hour

Fast Facts of Cong Sao Dessert

Two-Week Daily Order Count

Busiest days among a week: Friday, Saturday and Sunday Rush time each day: 9:30 PM to 11: 30PM

Mon Tue Wed Thu Fri Sat Sun 1st week 118 107 108 123 166 239 273 2nd week 114 111 134 124 149 279 267

How to Solve the Problem!

M/M/3

Equa&ons for mul&p le -channel queuing wai&ng model with Poisson arrival and exponen&al service Times (M/M/s) are complicated. Series of func&ons used by us are shown in right. Use the M/M/s Template in Excel to generate useful parameters for analysis.

M/M/s Template

Structure Of Dessert Shop

Before After

Capacity of Seats 68 Cooks 3 Waitress 5 Cashier 1 Salary of a Cook HK$15000 Per Month

Salary of a Waitress HD$12000 Per Month Average time for dessert preparation 6 minutes Per Order No. of total orders in rush hour 25 Per Hour No. of take-out orders in rush hour 10 Per Hour

Fast Facts No Way to Increase

Any More!!!

Three Recommendations

More Cooks (Cong Sao)

Delivery Service and Call & Pickup (Cong Sao)

Cycle Time Reduction (Customers)

More Cooks

Optimal Number of Cooks

Trade-off between

Cost of Service (SC) & Cost of Waiting (WC)

Total Expected Costs

Number of Servers

Costs

Cost of Service goes up as you pay for more servers.

Costs of Wai/ng goes down as service increases.

Total Cost

Op&mal # of servers

Note that the lowest cost system requires some customer wai/ng.

Fewer servers oJen means longer wai&ng for customers.

Many servers means liKle or no wai&ng, but higher service costs.

How to Measure the SC & WC

SC Hourly Wages of a Cook and a Waitress (Cs)

WC Hourly wages* of customers# lost in queuing (Ca) *Information from 2011 Hong Kong Population Census

Average working time are 49 hours per week from Report of Policy Study on Standard Working Hours, published by Labour Department of Hong Kong SAR # Customers here mainly refer to people living in Hang Hau East, where the dessert shop locates.

Ca=14,000/(49*4.25) =HK$67.23 Estimation for customers hourly wage.

Cs=(15,000+12,000)/(49*4.25)=HK$129.65 1 month = 4.25 weeks

More Cooks Input number of servers, 1, 2, 3, 4, 5, and 6 in to the yellow cell.

The optimal number of

Cooks is 4, which means Cong Sao should hire one more cook.

Delivery Service and Call & Pickup

No need to wait outside for take-out food

How to implement 1. Hire Part-time delivery person 2. Cross training is adopted.

Detailed feasibility analysis

Delivery Service

Customer calls in Order waits to be prepared Order is prepared Average time=6

minutes

Order waits to be delivered

Order is delivered Average time=20

minutes(round trip)

Flowchart for Delivery service (in rush time)

Delivery Service for local community should be priced reasonably or free when orders are big enough.

Cooking process Deliver process

Hire four part-time delivery persons, then the total time customer waits will be 37.01mins.

Call & Pickup

Customers order by phone and pick up desserts by themselves.

The accuracy of picking-up time estimation will be critical. Customers should be clearly informed when they can pick up their orders.

Cong Sao can offer 85% to customers.

Cycle Time Reduction

Pre-Order In Queue 1. Stick latest menus on external walls 2. make it easy for customer to check out 3. pre-order or offer self-order sheets 4. shorten the unnecessary order time

Re-check Number of Customers Write down the number of seats required for a group of customers. They will be allowed in, when it goes to their turn and all of their members gather.

Cycle Time Reduction

Background Music More arousing music leads individuals to carry out activities more quickly or spend less time on activities. Carefully select background music to make customers eat fast.

Discount For Fast Eating Offer Customers 10% discount if they can finish their desserts within 15 minutes, in peak time.

Conclusion

In this project, we describe a common queuing situation and present feasible mathematical models for analysis.

Shorten queue length outside to improve the quality of queuing and offer more convenience to customers.

Thank you!!!