Service Management: Capacity and Queuing

1. Software Downloads

• Learn and understand queuing dynamics:
• Queueing Experimentation (in Excel)
• Sandwich Simulation (includes little manual and uses ProcessModel software that comes with MBPF)

• Sof-Optics: For the Sof-Optics case, you should calculate queueing performance measures with a spreadsheet. You have a choice of two equivalent Excel aids that give exact performance statistics of a single-node, single-queue service facility with c customer service agents and a limited waiting room of K.  Your choices are:
1. The queue-performance spreadsheet: this is a simple spreadsheet with handy user-interface.
2. The Queueing ToolPak Excel add-in: Save the following file on your hard drive: qtp2_97.exe .  Then double click the file.  This will install all files associated with the Queueing ToolPak 2.01 in the appropriate folders.
• Activation: Open Excel and go to: Tools -> Add-ins. Scroll down the list and you should see "Queueing ToolPak 2.01". Check the box if it is not already checked and press OK.
• Try out this simple example.
• The add-in has the advantage that you can use functions in any cell (instead of having to call the queue-performance interface manual).  Plus, this add-in has good help files + now you can just calculate waiting time by inserting a function from the excel function line.
• The only slight disadvantage of the add-in, developed by colleagues at the University of Alberta, is that they use slightly different notation: Queue length Ii is denoted by Lq, and  flow time T is denoted by W, but that shouldn't create problems.
• For credits and updates: go to http://www.bus.ualberta.ca/aingolfsson/QTP
  
   
Notice:
• Both queue-performance and Queuing ToolPak assume that both interarrival and service times are exponentially distributed.
• If you want to have performance estimates of other interarrival and service time distributions, one must use simulation.  The results are estimates rather than exact and improve as the length of simulation is increased.  This simulation can be done in Process Model or also with the Excel spreadsheet Queueing Simulator.

2. Readings and Related Links

• Capacity Management and Queuing:
• Integrated forecasted, queueing and personnel staffing at Taco Bell.(OR/MS Today, October 97)
• Restructuring queues (McDonalds), FastPass (Disney), Incentive problems and paying for service
• Telemarketing:
• Waiting for Customer Service (WSJ.com, February 8, 2005)
• Virtual call centers and staffing: PDF article about My Twinn company. Original link from CIO, May 15, 2001.
• Call Centers: Ringing up big business
• Information on information systems for telemarketing, especially:
• Automatic Call Distributor Networking systems
• Integrating phone systems and databases
• Best practices report prepared by the National Performance Review (of Vice President Gore) on telephone service
• L.L. Bean
• LENS 4 ME
• Pricing to manage congestion and queueing:
• Netcom's New Price Model Tailors Internet Services (NY Times, 3/25/97).
• NPR interview (Jan 06, 2005) with MIT Professor Richard Larson on waiting lines at Disney, in banks, restaurants and other settings.