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Exam Exercises to practice. Operations Management previous exam...

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OPERATIONS MANAGEMENT EXAM prof. Alberto Portioli Staudacher, Marco Taisch & Matteo Rossini February 2nd, 2021 Exercise 1 (9 points) The Mega Mall is opening its doors for the 1st time with a special event that can hold up to 500 guests. The event consists in entertainment shows and dinner. The Mall wants to maximize the revenues from this event so they decided to offer two types of tickets: a discounted one that people can buy from 90 days to 30 days before the event at 200 € and a full price one that people can buy from 29 days to the day before the event at 600 €. They can certainly fill the venue selling only discounted tickets. The demand of full price tickets follows a normal distribution with mean 250 and a standard deviation of 50. The Mall is offering a welcome drink to all participants for 10 € each and will be paid by the official sponsor of the event. After the drink, a magic event will be shown for Full participants which cost 25 € per person actually present, paid by the Mall to the magician after the event. For Discounted customers, they can enjoy a gaming board which costs 10 € per person paid by the Mall two weeks before the event. Following that a dinner is offered to both customer types, and that costs 50 € for Full and 30 € for Discounted paid by the Mall two weeks before the event. The company has rented a security service for a total of 15000€

Data interpolation is not requested. You can take the value that is closest to the one you desire. Question 1) (3 points) Define how many tickets to allocate for each customer segment (Protection Level). Question 2) (2 points) Calculate the probability for the Mega Mall to reach a profit higher than 130 000 €. Question 3) (4 points) The Mega Mall has a building “FUN”. There, we have a movie screening theater and a souvenir shop. Assume that the rate of arrival of customers equals 24 customers/hour. There are two entrances for the movie theater, each has one host that can serve 20 customers/hour by giving them a seat number based on preferences. Following the movie, 10 % of all participants are expected to leave the building and the rest go to the souvenir shop where a DVD is handed out to participants. Participants wait in one line and then are served by two hosts, each host can serve 30 customers/hour. Assume the arrival and the service rates follow a negative exponential distribution. Calculate the throughput time in minutes for the average customer in building “FUN”.

Figure 1: Queuing System of Building "FUN"

OPERATIONS MANAGEMENT EXAM Prof. Alberto P ortioli St audacher, M arco Taisc h, Mat teo R ossini Exercise 2 (13 points)

CHOC S.p.a. operates in a B2B context producing, among the different products, boxes as packaging for chocolate bars. The company produces both standard and special boxes. The special are characterised by a customised colouring, following fashion trends and thus affected by obsolescence. The customisation starts in stage 3. Range of standard boxes is composed by 40 variants: 10 different sizes and 4 different colours. Demand for standard is stable and it is equal to 175 units per day, when a customer places an order for the standard unit, the shipping has to be the day after the order. Instead, the demand volume for special is 50 units per day distributed in 25 special orders per day on average (each special order is different from another special order). The LT for special boxes is quite high being it around 10 days. Production process: The production system is composed by 4 stages decoupled by stocks: S-1: there are 2 operators working in parallel in two separated semi-automatic machines. Each machine needs a setup if the size of the box changes; this stage is shared with other product families and it dedicates 50% of its time to the product family under analysis S-2: there is one operator that uses a semi-automatic machine. The operator performs manual activity in parallel with the machine processing. The operator manually loads the machine while the machine is still working the previous item and then he supervises the machine. Machine processing and unloading are automatic. The machine needs a setup if the size of the box changes; S-3: there is one operator that performs manual activity. The working station needs a setup if the colour of the box changes; S-4: there are 2 operators that performs same manual activity working in parallel in two separate working stations. The working station needs a setup if the colour of the box changes; this stage is shared with other product families and it dedicates 50% of its time to the product family under analysis. Each shift is 8 hours and there is a 30 minutes break per shift. Upstream S-1 there is a stock of raw material enough to cover 5 days of customer demand. There are no scraps in any process. Stage Shifts S-1 S-2 S-3 S-4

3 2 3 3

Cycle Time (min.) 3 (each operator) 1,5 (operator); 3,3 (machine) 3,4 5,4 (each operator)

Changeover (min.) 150 (size) 40 (size) 20 (colour) 20 (colour)

Availability (%) 90 95 100 100

Inventory (downstream) 900 1350 450 675

The company receives everyday customer orders and every day delivers to the customer. Company daily schedules the shipping department. The production control function issues a weekly production plan for each stage. Two times per week the S-1 informs production control about the raw material inventory level. The production control places a raw materials order to the supplier every two weeks and once per month it makes a forecast about the consumption of raw-materials and sends it to the supplier. The supplier delivers the day after the company order. Q1) (3 points) Draw the current state map of the operations system. Q2) (10 points) Create a future-state map of the system (answer the first six questions of the future state): Define the minimum changes in order to have an EPE value for standard product equaling to 2 days and to produce every day 50 special items (assuming that it is not possible to modify Availability, CT and shifts in future state improvement targets)

Operations Management Exam 02/02/2021...