Spreadsheet simulation for industrial application: a case study

The paper reports and demonstrates the spreadsheet simulation that used for production planning and inventory control in a composite based product manufacturer. It covers the development of the spreadsheet simulation template and the application. The findings show that the application of the spreadsheet simulation positively improve the time to estimate the production lead time, and monitoring activities on material usage included raw material, chemical and ancillary. Besides, it provides well-managed documentations for production planning and control

Exploring the bullwhip effect by means of spreadsheet simulation.

An important supply chain research problem is the bullwhip effect: demand fluctuations increase as one moves up the supply chain from retailer to manufacturer. It has been recognized that demand forecasting and ordering policies are two of the key causes of the bullwhip effect. In this paper we present a spreadsheet application, which explores a series of replenishment policies and forecasting techniques under different demand patterns. It illustrates how tuning the parameters of the replenishment policy induces or reduces the bullwhip effect. Moreover, we demonstrate how bullwhip reduction (order variability dampening) may have an adverse impact on inventory holdings. Indeed, order smoothing may increase inventory fluctuations resulting in poorer customer service. As such, the spreadsheets can be used as an educational tool to gain a clear insight into the use or abuse of inventory control policies and improper forecasting in relation to the bullwhip effect and customer service. Keywords: Bullwhip effect, forecasting techniques, replenishment rules, inventory fluctuations, spreadsheet simulationBullwhip; Bullwhip effect; Forecasting techniques; Inventory fluctuations; Replenishment rule; Simulation; Spreadsheet simulation;

Exploring the bullwhip effect by means of spreadsheet simulation.

One of the main supply chain deficiencies is the bullwhip effect: demand fluctuations increase as one moves up the supply chain from retailer to manufacturer. The Beer Distribution Game is widely known for illustrating these supply chain dynamics in class. In this paper we present a spreadsheet application, exploring the two key causes of the bullwhip effect: demand forecasting and the type of ordering policy. We restrict our attention to a single product two-echelon system and illustrate how tuning the parameters of the replenishment policy induces or reduces the bullwhip effect. We also demonstrate how bullwhip reduction (dampening the order variability) may have an adverse impact on inventory holdings and/or customer service. As such, the spreadsheets can be used as an educational tool to gain a clear insight into the use of inventory control policies and forecasting in relation to the bullwhip effect and customer service.Bullwhip effect; Replenishment rules; Forecasting techniques; Spreadsheet simulation; Beer distribution game;

HOG PRODUCER INVESTMENT IN VALUE-ADDED AGRIBUSINESS: RISK AND RETURN IMPLICATIONS

Although producers have been enticed into investment in value-added agribusiness the risk and return impacts have not been quantified. A spreadsheet simulation model is used to evaluate how investments by hog farmers in slaughter plants and other alternatives affect returns and risk. Results suggest that hog producer investment in value-added agribusiness is efficient.Value-Added, Producer Investment, Financial Economics, Livestock Production/Industries,

A Spreadsheet Simulation Of The Monty Hall Problem

The “Monty Hall” problem or “Three Door” problem—where a person chooses one of three doors in hope of winning a valuable prize but is subsequently offered the choice of changing his or her selection—is a well known and often discussed probability problem.  In this paper, the structure, history, and ultimate solution of the Monty Hall problem are discussed. The problem solution is modeled with a spreadsheet simulation that evaluates the frequencies of the possible outcomes (win or lose) under the two choices or strategies available:  switch to the unopened door or do not switch. A Law of Large Numbers approach is also used to graphically demonstrate the long run outcome of adopting one the two available strategies. As is known, the optimal strategy is to switch to the unopened door; the spreadsheet model illustrates why this strategy is optimal. A complete discussion of the spreadsheet logic is included. Pedagogical approaches and applications of the spreadsheet simulation approach are also discussed

Spreadsheet Simulation of Airline Reservation Policy Using Multimedia Software

A hypothetical business simulation case study using a stand-alone spreadsheet is used to illuminate the rationale of airline overbooking. Because almost everyone has personally encountered the implications of being “bumped,” the selection of this particular case subject is motivated by the belief that half of the problem (or more) of teaching a so-phisticated analytical method is in getting the stu-dent\u27s attention. Airline overbooking, it seems, pre-sents such a case. In order for a student to “drill down” the spreadsheet skills, several multimedia tools, Wimba and Jing, are used to produce web hosted, mp4 video files of a library of short films illustrating each step of the spreadsheet operatio

Exploring the bullwhip effect by means of spreadsheet simulation

An important supply chain research problem is the bullwhip effect: demand fluctuations increase as one moves up the supply chain from retailer to manufacturer. It has been recognized that demand forecasting and ordering policies are two of the key causes of the bullwhip effect. In this paper we present a spreadsheet application, which explores a series of replenishment policies and forecasting techniques under different demand patterns. It illustrates how tuning the parameters of the replenishment policy induces or reduces the bullwhip effect. Moreover, we demonstrate how bullwhip reduction (order variability dampening) may have an adverse impact on inventory holdings. Indeed, order smoothing may increase inventory fluctuations resulting in poorer customer service. As such, the spreadsheets can be used as an educational tool to gain a clear insight into the use or abuse of inventory control policies and improper forecasting in relation to the bullwhip effect and customer service. Keywords: Bullwhip effect, forecasting techniques, replenishment rules, inventory fluctuations, spreadsheet simulatio

Pathways of genetic adaptation: multistep origin of mutants under selection without induced mutagenesis in Salmonella enterica.

In several bacterial systems, mutant cell populations plated on growth-restricting medium give rise to revertant colonies that accumulate over several days. One model suggests that nongrowing parent cells mutagenize their own genome and thereby create beneficial mutations (stress-induced mutagenesis). By this model, the first-order induction of new mutations in a nongrowing parent cell population leads to the delayed accumulation of visible colonies. In an alternative model (selection only), selective conditions allow preexisting small-effect mutants to initiate clones that grow and give rise to faster-growing mutants. By the selection-only model, the delay in appearance of revertant colonies reflects (1) the time required for initial clones to reach a size sufficient to allow the second mutation plus (2) the time required for growth of the improved subclone. We previously characterized a system in which revertant colonies accumulate slowly and contain cells with two mutations, one formed before plating and one after. This left open the question of whether mutation rates increase under selection. Here we measure the unselected formation rate and the growth contribution of each mutant type. When these parameters are used in a graphic model of revertant colony development, they demonstrate that no increase in mutation rate is required to explain the number and delayed appearance of two of the revertant types

Introduction to Problem Solving Using a Monte Carlo Spreadsheet Simulation

At The Citadel, data collection, analysis, and problem solving is taught as part of the technical project management course for junior and senior engineering students. Many real world problems have such a broad scope or are so complicated that they resist a purely analytical solution. One technique for analyzing these complex problems is simulation. This paper describes the efforts to introduce students to spreadsheet-based Monte Carlo simulation modeling to support problem solving. Students can master spread-sheet-based simulation especially easily, and can expand their skill set by being taught to use real world data sets. The instruction introduces students to spreadsheet modeling with excel software and the fundamental aspects of data collection, analysis, and simulation modeling. The instruction aims to provide students with modeling skills to support problem solving. Students can master spread-sheet-based Monte Carlo simulation, and can expand their skill set by doing so. This paper describes the use of spreadsheet-based Monte Carlo simulation and briefly explores the underlying methodology using Excel to support the instruction

Development of spreadsheet simulation models of gas cylinders inventory management

The solution of the problem of managing the inventory of an enterprise whose activities are related to the purchase and sale of gas cylinders is considered. To solve the problem, it was necessary to investigate and choose the best inventory management strategy that provides the minimum value of the average inventory balance in the warehouse with the established upper limit of the average deficit. The problem of determining the best strategy is presented as a discrete programming problem, the required variables of which depend on the replenishment method. With a periodic replenishment strategy, the controlled variables are the volume of the delivery line and the delivery interval, with a threshold one, the minimum inventory level and the volume of the delivery line. Let’s also consider replenishment with a predicted inventory level, where the delivery level and the minimum inventory level are used as control variables. Three tabular simulation models with a given delivery time and random demand are proposed. Using the Chi-square test, it was found that the quantity demanded has a normal distribution law. By carrying out computational experiments, the optimal values of controlled variables were determined. The best objective function values were obtained using a model with a predicted inventory level and a threshold replenishment strategy. Experiments conducted on the basis of historical data have shown the advantage of the two model strategies compared to the strategy currently used in the enterprise. The use of a model with a predictable inventory level would reduce the average inventory balance by 46 %, and, consequently, save working capital. The results of the study can be useful for managers of enterprises whose activities are related to inventory managemen