14 02 20text

Pagina 1

Operations Management Exam page 1/2 EXERCISES (22 points) Exercise 1 (10 points) The “F.R.I.E.N.D.S” themed Library owned by Rachel Green is in New York. There are two different kinds of customers: students and retired people. On average, there are 20 retired people per day and 60 students per day entering Library. First step when entering the “F.R.I.E.N.D.S” library is the registration room, where they reserve the book they want to read, take the code of the book location. In this step, a single operator named Ross Geller serves the clients, one by one, by indicating where to take the book from. 15% of only students’ registrations are considered as a second registration because some students realize that they need some extra books and so they go back and reserve again. Retired people have a non-preemptive priority over students. After the registration room, the customers go to the second step of the process, in the reading room known as the “Smelly cat room” where they usually prepare exams or read respectively. At the entrance of the reading room, Monica & Chandler Bing, two librarians, help them according to single FIFO queue. After the reading room , one third of two-times registe red students and 10% of the retired people go home directly, so they leave the “F.R.I.E.N.D.S” library, while the remaining students and retired people go to the following step of the process, the Central Perk Cafeteria. In the cafeteria, Phoebe and Joey serve them, each of them serves his/her own queue. The “F.R.I.E.N.D.S” library works 8 hours per day. In the table below, the values of the service rate of the different resources are reported. For these resources, we can assume the arrival and the service rates follow a negative exponential distribution. Process Service rate (1 resource)…