CB9101 / ORBS7040 Simulation Modelling

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CB9101 / ORBS7040 Simulation Modelling

Simulation Project

Project deliverables

For this project, each student must produce the following:

· An executive summary

· A technical appendix

· A baseline SIMUL8 model

· A SIMUL8 model with recommended changes

Details on each component are provided in Section 2 of this document.

Important dates

The executive summary, technical appendix, and SIMUL8 models should be uploaded to Moodle before 17:00 Friday 28 June 2024 (UK time).

1. Background

Your consulting firm has just been hired on by Avanti, a large, international pharmaceutical company, to help improve operations at its vaccine production facility in Oxfordshire. More specifically, the company is interested in analysing possible changes in the production of its Yellow Fever vaccine.

To produce a batch of Yellow Fever vaccine, it is first necessary to grow an attenuated virus in a large fermenting vat containing a serum supplemented culture of canine kidney cells for about 2 to 5 days until a sufficient density of cells is reached. The cell culture then needs to cool down for at least 40 minutes before being moved to the next step in the production chain - extraction and purification. Data regarding the time it takes for extraction and purification has been provided for you to analyse (check on Moodle for an Excel file containing this data). You will need to determine an appropriate distribution to use (e.g., using Stat::Fit, EasyFit or some other similar statistical fitting software). Note that before the fermenting vat can be used again, it needs to be cleaned and disinfected, which takes about 2 hours ± 15 minutes.

After purification, each batch of attenuated vaccine needs to be tested. This normally takes 50 minutes with a standard deviation of 5 minutes. Batches that meet quality standards are then sent on to the packaging department to be put into vials, from which 9,000 to 11,000 doses can be obtained per batch. Based on experience, the number of doses follows a beta distribution with shape parameters  and . The time it takes to process a batch into vials and package them is 60 seconds per 1,000 vials.

In 4% of cases, a batch of cell culture is found to have been contaminated and simply needs to be discarded. In another 20% of cases, batches are found to contain impurities during the testing phase and thus need to be further treated before being retested. This can take anywhere between one and three hours. Batches that have been retreated all pass testing the second time.

Relevant price and cost information for manufacturing the vaccine is as follows:

· Each useable vial of Yellow Fever vaccine can be sold to public and private health care providers at a price of £20 per vial.

· The cost for the various raw materials and the expense of running and cleaning the fermentation vat is about £20,000 per batch.

· Purification costs a total of £3,000 per batch.

· Testing incurs a cost of £1,500 per batch.

· The cost to dispense the vaccine into vials and package them is £0.50 per useable vial of vaccine.

· The overhead and running cost for the Yellow Fever vaccine production facility is £220,000 per month.

Avanti currently operates a total of 5 vaccine fermentation vats and has capacity to purify and test 8 batches of vaccine simultaneously. The packaging area, meanwhile, can handle up to a total of 6 batches of vaccine simultaneously.

Avanti would like to maximize its profits by increasing production at its Yellow Fever vaccine production facility. Taking into account nominal prices and competition from its various rivals, Avanti believes that up to 25 million vials of the vaccine could be sold per year. Your task is to construct a computer simulation model of Avanti’s Yellow Fever vaccine production facility and advise the company on what changes can be made to improve profits. To simplify things, you can ignore the cost of purchasing and operating additional machinery, including fermenting vats, extraction and purification devices, etc.

Do bear in mind that precise details of each distribution are not given. In some cases you can infer what distribution to use, in others you will have to use your judgment. If there is anything else you are unsure of, make a sensible assumption and explain it in your report (see below).

2. Instructions

The deadline for the project is 17:00 Friday 28 June 2024 (UK time). You must prepare a report for Avanti. The main body of the report (the executive summary) should not exceed 6 typed pages of A4 paper (11 point font, single spacing). You should also include a technical appendix with a maximum length of 8 pages. Details of what should be included in the executive summary and technical appendix are provided below. Be sure to put your name on the report! The managers at Avanti will want to know who it has come from. The executive summary, technical appendix, and SIMUL8 model(s) should all be uploaded to Moodle before the deadline. Late work will not be accepted.

2.1 Executive summary (60%)

Discuss in detail 1) the current production capacity of the Yellow Fever vaccine production facility and 2) any changes you would recommend employing. In particular, highlight any important findings you have discovered about the vaccine production current operations that you wish to bring to the attention of Avanti’s management. Then describe the various alternative system configurations you have tried and explain why your recommendation is best. If you believe any of the targets is unrealistic, then you should explain why and recommend suitable changes. Please note, this part of the report should be written for a business audience.

2.2 Technical appendix and SIMUL8 model(s) (40%)

Briefly describe the setup and flow of your model. Be sure to include a figure showing your model. You can use the print screen button on your keyboard to copy the model from SIMUL8 and then paste it into your document. In addition, annotate the figure and provide a “walk-through” of the model so that it is clear what is happening at each step of the whole process. Highlight any special features of your model.

Give a brief description of which distributions you chose and why. Think about summarising all of this in a table. A good report should also include a brief analysis of how sensitive your results are to the distributions you have chosen, especially for extraction and purification time (i.e. try running a sensitivity analysis on the different fitted distributions derived from Stat::Fit or other distribution fitting software).

How did you set-up and run your simulations? For example, what did you choose as the total run time for your model? How many trials did you perform for each experiment? Was a warm-up period required? Give a brief justification.

Discuss some of the key assumptions and limitations of your model. What does your model unrealistically impose or fail to consider that occurs in the real-world? How might this be affecting your results?

The main focus of the technical appendix should be on running experiments and analysing results. A good report should contain a number of tables and or figures summarising your results, along with a thorough analysis and discussion of key findings. Be sure to include confidence intervals on any reported results!

DO NOT simply copy and paste raw outputs from SIMUL8 into your report! Instead, you should provide nicely formatted figures and tables of results. Also, instead of simply giving a single “answer” or recommendation, consider developing multiple scenarios (e.g. different combinations of resources, different timings on work centres, etc.) and show how the results vary for each scenario.

2.3 Marking criteria

A good project should show that you have achieved the objectives of the module. Projects will be marked accordingly. Thus, there will be marks for developing an appropriate simulation model, analysing the model and communicating the outcome of that model to a non-specialist audience (i.e. the managers of Avanti). Marking criteria for this quantitative case-study assessment are provided below.

Categorical Marking Criteria

Generic/categoric marking criteria will be used to assess the project. The three generic criteria “Communication”, “Understanding, Analysis & Argument” and “Organisation and Presentation” do not have arithmetic weightings. Your overall mark will be based on the marker’s judgement of your overall performance across these three criteria. You will be given feedback which will: (i) show your overall mark; (ii) indicate your performance in each of the three criteria; and (iii) suggestions on how your work could be improved.