Examples

This BSc thesis is about the inventory in the supply chain, service levels and an application of these concepts on supermarkets. The different types of inventory are decoupling inventory, cycle inventory and safety inventory. Which type a company has depends on their strategy. Almost all companies work with service levels. A service level is a measurement of product availability for customers. There are two types discussed: The α-service level and the β-service level. The α-service level is also called the cycle service level (CSL) and the β-service level is also mentioned as the fill rate. For both types there are several formulas to calculate the level of inventory and the order-up-to level with a given service level.

In the context of supply chain sustainability improvement, Multi-Criteria Decision Making is a usual tool to determine an optimal resource distribution. However, applying this type of analysis presents a number of practical inconveniences. To avert these drawbacks, the study tries to adapt a different approach, originally introduced in healthcare, to supply chains. An analysis is made of this alternative programming model, as well as an explanation of the adjustments required to convert the model from the healthcare to the supply chain context.

When considering perishable products, the trade-off between waste and shortage is important. A safety stock functions as a buffer for uncertainty in demand during a week, and will influence the amount of shortage and waste. The purpose of this study was to conduct research into the consequences of using a certain rule of thumb related to order policies for supermarkets facing non-stationary demand of a perishable product.

In this research, three rules of thumb for setting the order-up-to-level  were tested and evaluated by simulation in Excel. The first rule, 1S1X, consists of a constant order-up-to-level that is not weekday dependent with one safety factor, as if demand is stationary. The second rule, 6S1X, considers six different order-up-to-levels for the different weekdays, optimised by one safety factor. The most extensive rule, 6S6X, also considers six order-up-to-levels, now optimised with weekday dependent safety factors.

The research shows that when the 6S6X rule is used for replenishment when facing non-stationary demand, the costs of shortage and waste were lowest for most experimental conditions. Surprisingly, having six order-up-to-levels optimised by one safety factor (6S1X-rule) is worse than a constant order-up-to-level.

This BSc thesis is a follow up on the MSc of Sijtsma (2016). In the thesis of Sijtsma (2016) a variant for the Economic Order Quantity model (EOQ) was developed for mangoes by adding the storage temperature to the model. The aim of this thesis is to find out if there has been done research about adding product decay to the EOQ model other than the research of Sijtsma (2016) and to find out what data should be collected to confirm her adapted model with real data.

In the first part, some of the articles from the literature overview from Bakker, Riezebos and Teunter (2012) combined with new found articles are transformed in a new literature overview. This desk research shows that there are a lot of general extensions to the EOQ model to make it suitable for deteriorating products. However, knowledge about EOQ models for specific products or with the application of microbial and enzymatic degradation is scarce.

In the second part of the research, the extended model of Sijtsma (2012) is explained, followed by a part where the required information is presented and illustrated from a small scale example. Before getting the information it’s important to know how the transportation costs are calculated and how many supplier there are. The fitted constants are not adaptable to the situation yet, since it is unknown how to calculate them. This, together with the estimated data and little transportation time, are the reasons why the results of the calculations are a bit high.

Further research is needed to develop more EOQ models which implement microbial and enzymatic degradation and are modelled for specific product(categorie)s. It is also recommended to do some calculations with the adapted EOQ model of Sijtsma (2012) with data from real life cases.

This BSc thesis is about land-use optimization in Dutch agriculture. Optimizing the use of resources is nowadays very important, the world’s population is growing and the area of agricultural ground is decreasing. Farmers are more exposed to the world market and their prices, quota on products like sugar beets and milk have been abandoned. This puts our farmers in a somewhat unreliable position. Therefore the aim of this thesis was to see if it is possible to make a model taking a price and yield uncertainty into account.

In this BSc thesis this problem is tackled using a linear programming with some stochastic variables. First a small literature review has been done to see what has already been done on this topic and to determine a proper methodology. Following this literature review a the model is made. The results following retrieved from the model are analysed and discussed.

The current situation in Ethiopia is critical, as almost half of the children are underfed. To make the problems even worse, overnutrition is becoming an emerging problem as well, together with a lack of important nutrients in the diets.

This study uses linear programming to create a practical, nutritious and healthy diet for Ethiopian women of reproductive age. An Extended Goal Programming model has been created in FICO Xpress IVE to provide practical and pragmatic insights to the Ethiopian population.

To combat the existing and emerging problems, the linear programming model creates a diet which complies to all nutritional requirements. To keep the results practical, the Extended Goal Programming model minimized the differences between the actual consumption and the suggested diet by the model. This forces the solution to be closer to the current habits of the target group. The solution provided a balanced, nutritious and most importantly, a healthy diet, close to the real consumption of both Ethiopians living in rural and urban areas.

This research quantifies the bullwhip effect in a three-stage supply chain. The goal of the research is to determine how lead times are influencing the bullwhip effect. First, a literature review is conducted in order to find the causes of the bullwhip effect and to determine how the bullwhip is measured. The literature review showed that the main causes of the bullwhip effect are: order batching, demand signal processing, gaming behavior and price variations. After the literature review, a 3-stage supply chain model is built in which the bullwhip effect is quantified on the basis of lead times.

The model contains a manufacturer, a distributor and a retailer. It is a single item model. The results show that the bullwhip effect is influenced by lead times. As longer lead times require more safety stock. A higher safety stock means a higher inventory, and this allows more fluctuation. Which is reflected in the bullwhip effect.

Selecting the right assortment for a supermarket can be very crucial. The aim of this bachelor thesis is show how an assortment optimization model can support the decision-making process of choosing the optimal assortment for a supermarket. Literature study is done to get insight in what type of factors could be taken into account by assortment optimization models. With the knowledge obtained from literature study, factors are selected and a mixed-integer linear programming (MILP) is designed that determines the assortment with the highest profit. With the use of a designed dataset of 200 coffee products the model is applied and the optimal assortment for this product category is calculated by Fico Xpress. The results found from this analysis are that the products with the highest profit margin, highest demand and/or products that need a small shelf space are included in the optimal assortment. This research also found that the profit margin and the demand have the most impact on determining the optimal assortment. Using assortment optimization models are very effective in finding the assortment with the maximal profit and there seems to be a clear relationship between the profit and the amount of products in the assortment.