Students

1.        Submission Deadline: 5 pm Monday 3rd  November 2025.

2.        Format Requirements:

•          Assignments must include the cover page with your student ID.

•          The format of the assignment comprises simply a response to each of the requirements.  Thus, the assignment is not a report: Introductions, Executive Overviews, and Tables of Contents are NOT wanted.

•          All assignments must be typed, proof-read, and professional in appearance

•           The word font should be 'Arial' or 'Calibri' and font size 12 with 1.5 spacing.

•           The left and right margins should be 'Justified'.

•          Harvard Referencing if citation and references apply.

•          ALWAYS make variables italic or blue in paragraphs where discuss about them.

3.        Submission Requirements:

•          Name Word file as IFB315TC-CW2-Your ID.

•          A group should submit one document a. Word format of Part 1 to LMO for group questions.  Each student should also submit two documents, including b. Word format of Part 2, c. Vensim file of Part 2 to LMO for individual questions. Only electronic submission is accepted and no hard copy submission.

•          All students must download their file and check that it is viewable after submission. Documents may become corrupted during the uploading process (e.g. due to slow internet connections).  However, students themselves are responsible for submitting a functional and correct file for assessments.

Assessment tasks:

Simulation of Supply and Demand of Filtration Devices in Dialysis Machines Using Vensim PLE

Braun Melsungen AG is a German company that offers products and solutions for infusion therapy, nutrition therapy and pain management. The company safeguards the functionality of medical care  that requires operations  planning,  including reliable and upgradeable supply chains to integrate smart IT solutions into the hospital processes. Braun Melsungen AG is also a leading company in the hemodialysis market. You are in charge of the supply and demand planning of filtration devices (let’s say filters) used in dialysis machines made by Braun Melsungen AG.

Figure 1:  dialysis machines (left) and filters (right)

Braun Melsungen AG is mostly efficient regarding dialysis machines market. However, it is common to see the company  experiences periods of low capacity utilization followed by substantial production increase and extra shifts. Your colleagues believe that the situation is due to the demand fluctuation and economy instability, but you have your own thoughts.  Rechecking supply by your company and demand by hospitals over the last 120 months and drawing the following graphical statement about the corresponding supply and demand of filters, you get the impression that demand has more stability than supply.

Figure 2: the supply by your company and demand by hospitals over the last 120 months

Your aim is to determine what the reason behind this can be, and how you can resolve it. To do so, you want to simplify as much as possible your current situation to deal with it easier. The reason of simplification is to find solutions quickly in the line with a reliable supply chains and decide if you are on the right track. In addition, it is more effective to start with a basic model and extend it, than to create a complex model and attempt to obtain useful information from it after it is completed. Let us now take a few general observations about how the business operates.

1. The only source of supply is in-house production of filters in the company.

2. The only source of demand is sale to dialysis clinics in hospitals.

3. Inventory will never increase if there is no fabrication of filters.

4. The company cannot deliver filters to dialysis clinics in hospitals if there is not any inventory in its warehouse.

5. There is a current backup of 300,000 filters in the company stored in the case if there is no worker.

6. The process of training a newly-haired employee to be eligible for work takes two months under the most favorable conditions.

7. Similarly, the process of ending the contract of a currently employee also required a two months’ notice.

8. A trained employee makes 1,000 filters per month and under the best-case scenario in which he productively works the entire 8 hours a day. However, in reality, an employee is 6.4 hours productive a day.

9. Currently, 125 employees work in the company to fulfill a fixed demand of 100,000 filters per month.

Part 1

Assume that manufacturing of filters is related in a make-to-stock (MTS) strategy with a “non- adoptive” manner. For such a manner, production is required to first fabricate filters and then sell. This is to say that the demands of filters are not immediately met when supply happens.

1.  Your task is to draw a stock and flow diagram related to the non-adoptive supply and demand, and then insert its Vensim image in your Word document. (group, 15 Marks, 50 words limit)

2.  There is a set of variables used in the stock and flow diagram. Briefly explain variables used in this diagram and relationship between them. (group, 20 Marks, 350 words limit)

Part 2

3.  It is now vital to realize the way supply of filters is decided. To do so, consider the following statement: “Investment and capacity are important and stable over a long-term vision. However, the company should hire or dismiss employees to a desirable point every 2 years once if there is a change in the demand.”. Let’s assume that monthly demands in the first, second, third, fourth, and fifth two-year time intervals are fixed and equal to 100,000, 120,000, 70,000, 110,000, and 110,000 units of filters, respectively.

Your task is:

a.  to write down the Vensim equations used for this model with a setting of 120 months (add all of them to Word document)

b.  to draw strip graph figures of changes of stock levels and axillary variables developed in the model for the non-adoptive manner of supply and demand of filters (insert them in your Word document),

c.  to make a table depicting the sensitivity analysis for each of five two-year time intervals. (Individual, 30 Marks, 200 words limit)

4.  Now, assume that manufacturing of filters is related in a make-to-stock (MTS) strategy with an “adoptive” manner. Due to the adaptivity, the stock decisions are also based on the current or recent demands. The stock correction that is the correction for a deviation of stock from its desired value due to unpredictability in demand of filters is not an immediate action. Instead, the stock correction can last two months.

Similar to Q3, assume the monthly demands in the first, second, third, fourth, and fifth two-year time intervals are fixed and equal to 100,000, 120,000, 70,000, 110,000, and 110,000 units  of filters,  respectively.  In  addition, consider the following statement: “Because of poor demand forecasting in the first three two-year time   intervals, overstocking equal to the triple of demand is unavoidable for each of these three two- year time intervals. However, the demand forecasting can be improved in the last two two-year time intervals and so there is no need to overstock filters in the corresponding two two-year time intervals.”.

Your task is:

a.  to draw an extended stock and flow diagram related to the adoptive supply and demand,

b.  to write down only the additional Vensim equations used for this model with a setting of 120 months (add all of them to Word document)

c.  to draw strip graph figures of changes of stock levels and axillary variables developed in the new model (insert figures in your Word document)

d.  to make a table depicting the sensitivity analysis for each of five two-year time intervals.

The Vensim file ended with PART2-Your ID.mdl should also be submitted. (Individual, 35 Marks, 250 words limit)

Word limit:

850 words (not including data presented in figures or attachments).

Marking Criteria