• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 18
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 31
  • 15
  • 10
  • 8
  • 8
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Etablering av strategier och rutiner för seriestorlekar : En fallstudie på Företag X / Establishment of strategies and routines for production sizes : A case study at Company X

Vinberg, Karl, Klevtun, Lukas January 2021 (has links)
Purpose: The purpose of the study is to identify, design and apply a method for operational production planning. The purpose of the method is that it takes into account the respective demand patterns of the articles, which determines the choice of calculation model and that the method also takes into account the production capacity limitation set. The result can be applied as a basis for decision-making for small and medium-sized manufacturing companies that are facing an expansion. Objective: The following research question was the main objective of this study.How would an appropriate operational planning method be shaped according to the specific characteristics of the products and their diverse demand patterns in small and medium-sized manufacturing companies with capacity limiters? Method: The study is a qualitative one-case study with quantitative elements. The empirical data used in the study was collected through unstructured and semi-structured interviews where the snowball effect has been applied and also observations have been performed. Results: The study has enabled a higher degree of utilization of the capacity limitation set, by developing standardized block sizes. The first step was to identify demand patterns into which the studied articles could be categorized. The demand pattern was applied in order to be able to apply the correct calculation model to the correct article. The calculation model was then standardized by applying PoT to be able to obtain standardized block sizes. The method was illustrated in a Gantt chart to demonstrate its usefulness. / Syfte: Studiens syfte är att identifiera, utforma och applicera en metod för operativ produktionsplanering. Ändamålet med metoden är att den tar hänsyn till artiklarnas respektive efterfrågemönster vilket avgör valet av beräkningsmodell samt att metoden tar även hänsyn till produktionens kapacitetsbegränsning ställare. Resultatet kan appliceras som beslutsunderlag för små samt medelstora tillverkande företag som står inför en expansion. Forskningsfråga: Följande forskningsfråga var objektet för denna studie. Hur skulle en lämplig operativ planering formas utefter artiklarnas specifika egenskaper och deras olikartade efterfrågemönster hos små och medelstora tillverkande företag med kapacitetsbegränsningen ställare? Metod: Studien är en kvalitativ en-fallstudie med kvantitativa inslag. Den empiriska data som använts i studie än insamlad genom ostrukturerade samt semistrukturerade intervjuer där snöbollseffekten tillämpats och även observationer har utförts. Resultat: Studien har möjliggjort en högre utnyttjandegrad av kapacitetsbegränsningen ställare, genom att framta standardiserade blockstorlekar. Första steget var att identifiera efterfrågemönster som de studerade artiklarna kunnat kategoriseras in i. Efterfrågemönstret har tillämpats för att kunna använda rätt beräkningsmodell på rätt artikel. Beräkningsmodellen standardiserades därefter genom tillämpning av PoT för att kunna erhålla standardiserade blockstorlekar. Metoden illustrerades i ett Gantt-schema för att påvisa dess användbarhet.
22

Data Science and the Ice-Cream Vendor Problem

Azasoo, Makafui 01 August 2021 (has links)
Newsvendor problems in Operations Research predict the optimal inventory levels necessary to meet uncertain demands. This thesis examines an extended version of a single period multi-product newsvendor problem known as the ice cream vendor problem. In the ice cream vendor problem, there are two products – ice cream and hot chocolate – which may be substituted for one another if the outside temperature is no too hot or not too cold. In particular, the ice cream vendor problem is a data-driven extension of the conventional newsvendor problem which does not require the assumption of a specific demand distribution, thus allowing the demand for ice cream and hot chocolate respectively to be temperature dependent. Using Discrete Event Simulation, we first simulate a real-world scenario of an ice cream vendor problem via a demand whose expected value is a function of temperature. A sample average approximation technique is subsequently used to transform the stochastic newsvendor program into a feature-driven linear program based on the exogenous factors of probability of rainfall and temperature. The resulting problem is a multi-product newsvendor linear program with L1-regularization. The solution to this problem yields the expected cost to the ice cream vendor as well as the optimal order quantities for ice cream and hot chocolate, respectively.
23

Applying Deep Learning to the Ice Cream Vendor Problem: An Extension of the Newsvendor Problem

Solihu, Gaffar 01 August 2021 (has links)
The Newsvendor problem is a classical supply chain problem used to develop strategies for inventory optimization. The goal of the newsvendor problem is to predict the optimal order quantity of a product to meet an uncertain demand in the future, given that the demand distribution itself is known. The Ice Cream Vendor Problem extends the classical newsvendor problem to an uncertain demand with unknown distribution, albeit a distribution that is known to depend on exogenous features. The goal is thus to estimate the order quantity that minimizes the total cost when demand does not follow any known statistical distribution. The problem is formulated as a mathematical programming problem and solved using a Deep Neural network approach. The feature-dependent demand data used to train and test the deep neural network is produced by a discrete event simulation based on actual daily temperature data, among other features.
24

Modelování vybraných rizik ve zdravotnictví / Modelling of Selected Risks in Healthcare

Nováková, Pavlína January 2021 (has links)
The diploma thesis deals with the modeling of selected risks in healthcare. Motivated by the current pandemic situation, it focuses on analysis of risks associated with the vaccination center in Brno. The theoretical part is mainly devoted to the issue of risk management with a focus on risks in healthcare, where the methods that are used in the practical part are defined. Furthermore, the thesis presents selected topics of mathematical programming. Especially, the newsvendor problem is introduced as inspiring case for further modelling. The brief description of the covid-19 pandemic situation later serves as one of the data sources. The practical part deals with the description and risk analysis of the vaccination process using the methods "What If?" and the FMEA method. Appropriate decisions are then proposed for selected risk situations using the GAMS optimization system. Based on the results of the calculations, specific recommendations are proposed.
25

Enhancing the Efficacy of Predictive Analytical Modeling in Operational Management Decision Making

Najmizadehbaghini, Hossein 08 1900 (has links)
In this work, we focus on enhancing the efficacy of predictive modeling in operational management decision making in two different settings: Essay 1 focuses on demand forecasting for the companies and the second study utilizes longitudinal data to analyze the illicit drug seizure and overdose deaths in the United States. In Essay 1, we utilize an operational system (newsvendor model) to evaluate the forecast method outcome and provide guidelines for forecast method (the exponential smoothing model) performance assessment and judgmental adjustments. To assess the forecast outcome, we consider not only the common forecast error minimization approach but also the profit maximization at the end of the forecast horizon. Including profit in our assessment enables us to determine if error minimization always results in maximum profit. We also look at the different levels of profit margin to analyze their impact on the forecasting method performance. Our study also investigates how different demand patterns influence maximizing the forecasting method performance. Our study shows that the exponential smoothing model family has a better performance in high-profit products, and the rate of decrease in performance versus demand uncertainty is higher in a stationary demand environment.In the second essay, we focus on illicit drug overdose death rate. Illicit drug overdose deaths are the leading cause of injury death in the United States. In 2017, overdose death reached the highest ever recorded level (70,237), and statistics show that it is a growing problem. The age adjusted rate of drug overdose deaths in 2017 (21.7 per 100,000) is 9.6% higher than the rate in 2016 (19.8 per 100,000) (U. S. Drug Enforcement Administration, 2018, p. V). Also, Marijuana consumption among youth has increased since 2009. The magnitude of the illegal drug trade and its resulting problems have led the government to produce large and comprehensive datasets on a variety of phenomena relating to illicit drugs. In this study, we utilize these datasets to examine how marijuana usage among youth influence excessive drug usage. We measure excessive drug usage in terms of drug overdose death rate per state. Our study shows that illegal marijuana consumption increases excessive drug use. Also, we analyze the pattern of most frequently seized illicit drugs and compare it with drugs that are most frequently involved in a drug overdose death. We further our analysis to study seizure patterns across layers of heroin and cocaine supply chain across states. This analysis reveals that most active layers of the heroin supply chain in the American market are retailers and wholesalers, while multi-kilo traffickers are the most active players in the cocaine supply chain. In summary, the studies in this dissertation explore the use of analytical, descriptive, and predictive models to detect patterns to improve efficacy and initiate better operational management decision making.
26

A Seasonal Shelf Space Reorder Model Decision Support System

Horne, Susan Elaine January 2010 (has links)
No description available.
27

Mathematical Programs for Dynamic Pricing - Demand Based Management / Mathematical Programs for Dynamic Pricing - Demand Based Management

Hrabec, Dušan January 2017 (has links)
Tato disertační práce se zabývá vývojem, modelováním a analýzou poptávkově orientovaných úloh, které zahrnují marketingová, operační a logistická rozhodnutí. Úlohy jsou zvoleny tak, aby mohly být dále rozšířeny o koncept tzv. dynamického oceňování a jiných dynamických marketingových rozhodnutí. V práci jsou využity dvě základní poptávkově orientované úlohy: a) úloha kolportéra novin, která je zvolena pro její jednoduchou formu a která tak slouží jako nástroj pro ilustrativní ukázky rozhodovacích procesů v podobných typech úloh, a b) úloha návrhu dopravní sítě, kde jsou využity některé výsledky a znalosti získané při řešení úlohy kolportéra novin. Kolportér (či obecně maloobchodník) čelí náhodné poptávce, která může být postupně ovlivněna oceňováním, marketingovými (tj. reklamními) rozhodnutími a nakonec jejich kombinací. Poptávka obsahuje tedy náhodnou složku, která je pomocí přístupů stochastické optimalizace modelována ve specifickém tvaru (tj. aditivní či multiplikativní tvar). Závislost cena-poptávka je zachycena pomocí nelineární klesající poptávkové funkce, zatímco (vhodná) reklama vede ke zvýšení poptávky (běžně rostoucí s-křivka či konkávní funkce). Výsledky získané při řešení úlohy kolportéra novin s oceňováním jsou následně využity v úloze návrhu dopravní sítě. Tato stochastická úloha je modelována (reformulována) pomocí dvou přístupů stochastické optimalizace: wait-and-see přístup a here-and-now přístup. Jelikož tato implementace vede na lineární či nelineární celočíselnou (navíc scénářovou) úlohu, jsou v práci zmíněny taky výpočetní nástroje. Autor pro řešení používá (původní) tzv. hybridní algoritmus, což je kombinace heuristického (genetického) algoritmu a nástroje optimalizačního softwaru. Potenciální aplikace sestavených modelů, obzvláště v oblasti odpadového hospodářství, jsou diskutovány v závěrečné části disertační práce.
28

Effect of Supply Chain Uncertainties on Inventory and Fulfillment Decision Making: An Empirical Investigation

Paul, Somak 02 October 2019 (has links)
No description available.
29

Quadratic Spline Approximation of the Newsvendor Problem Optimal Cost Function

Burton, Christina Marie 10 March 2012 (has links) (PDF)
We consider a single-product dynamic inventory problem where the demand distributions in each period are known and independent but with density. We assume the lead time and the fixed cost for ordering are zero and that there are no capacity constraints. There is a holding cost and a backorder cost for unfulfilled demand, which is backlogged until it is filled by another order. The problem may be nonstationary, and in fact our approximation of the optimal cost function using splines is most advantageous when demand falls suddenly. In this case the myopic policy, which is most often used in practice to calculate optimal inventory level, would be very costly. Our algorithm uses quadratic splines to approximate the optimal cost function for this dynamic inventory problem and calculates the optimal inventory level and optimal cost.
30

Newsvendor Models With Monte Carlo Sampling

Ekwegh, Ijeoma W 01 August 2016 (has links)
Newsvendor Models with Monte Carlo Sampling by Ijeoma Winifred Ekwegh The newsvendor model is used in solving inventory problems in which demand is random. In this thesis, we will focus on a method of using Monte Carlo sampling to estimate the order quantity that will either maximizes revenue or minimizes cost given that demand is uncertain. Given data, the Monte Carlo approach will be used in sampling data over scenarios and also estimating the probability density function. A bootstrapping process yields an empirical distribution for the order quantity that will maximize the expected profit. Finally, this method will be used on a newsvendor example to show that it works in maximizing profit.

Page generated in 0.0659 seconds