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  • 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.
31

Sediment Transport Conditions Near Culverts

Rowley, Kyle Jay 01 August 2014 (has links) (PDF)
Relatively little work has been done to understand how coarse grained sediments behave near culverts. Particularly for embedded culverts, sediment transport must be understood to achieve sustainable culvert designs for aquatic organism passage and peak discharge requirements. Several culvert sites in the Wasatch Mountains of Utah were studied through the spring flood season of 2014. Data obtained from the culvert sites were used to create numerical models with the Sedimentation and River Hydraulics Two-Dimensional model. The field sites and numerical model were used to study deposition of sediments at the entrance to culverts, sediment replenishment inside culverts, and lateral fining within the culvert barrel. Each element of the study was observed in the field. It was shown that the Sedimentation and River Hydraulics Two-Dimensional model is a useful tool to simulate the observed phenomenon of sediment deposition upstream of culverts, sediment replenishment, and lateral fining. Sedimentation and River Hydraulics Two-Dimensional model should be used in culvert design procedures as a means to understand sediment transport conditions.This work documents the first time that deposition of sediments upstream of a culvert and lateral fining within a culvert barrel have been successfully modeled. The work shows that culvert replenishment occurs naturally in many scenarios and should be simulated as part of the culvert design process. The results from this work will be useful for future design guidelines for culvert installations.
32

Optimized material flow using unsupervised time series clustering : An experimental study on the just in time supermarket for Volvo powertrain production Skövde.

Darwish, Amena January 2019 (has links)
Machine learning has achieved remarkable performance in many domains, now it promising to solve manufacturing problems — a new ongoing trend of using machine learning in industrial applications. Dealing with the material order demand in manufacturing as time-series sequences, making unsupervised time-series clustering possible to apply. This study aims to evaluate different time-series clustering approaches, algorithms, and distance measures in material flow data. Three different approaches are evaluated; statistical clustering approaches; raw based and shape-based approaches and at last feature-based approach. The objectives are to categorize the materials in the supermarket (intermediate storage area to store materials before assembling the products) into three different flows according to their time-series properties. The experimental shows that feature-based approach is performed best for the data. A features filter is applied to keep the relevant features, that catch the unique characteristics from the data the predicted output. As a conclusion data type, structure, the goal of the clustering task and the application domains are reasons that have to consider when choosing the suitable clustering approach.
33

Magma Mixing and ReplenishmentBeneath Laurens Peninsula, Heard Island / Magmablandning och påfyllning underLaurens Peninsula, Heard Island

Telson, Ransom January 2022 (has links)
Heard Island is a remote Australian territory which lies in the South-middle sector of the Indian Ocean.The island lies in the central province of the Kerguelen Plateau. On the north-western face of the islandlies the Laurens Peninsula, where modern volcanism has been periodic since approximately 10 ka, butno eruption has been recorded. The main volcanic feature of the peninsula is Mt Dixon of which noactivity has been observed but it is thought to have erupted within the past few hundred years. This thesis applied the crystal size distribution method to three thin sections from the LaurensPeninsula. The samples were collected from a phonolite from Jacka valley, a teprhiphonolite from thebase of the Red Island cone, and a tephrite east of Cape Cartwright. Crystal dimensions were calculatedusing ImageJ Fiji, these dimensions were corrected for 3D dimensions using CSDslice, and the datawas plotted using CSDcorrections. Microcrysts were traced using backscattered electron (BSE) images,and high resolutions scans of the thin section were used to trace phenocrysts. The results of the crystalsize distributions show concave-up shapes in all plots with steep slopes for smaller crystals, followedby shallow slopes for larger crystals. This suggests binary magma mixing by replenishment occurred inthe magmas associated with all three samples. The different slopes suggest two separate crystallisationconditions: Phenocrysts crystalized slowly in the chamber and microcrysts crystallized relativelyquickly during or after eruption. Textural differences in the three samples suggest that the tephrite hadthe longest residence time and underwent the most replenishment events, followed by thetephriphonolite and lastly the phonolite. Finally, since replenishment is the mechanism of mixingbeneath the Laurens Peninsula, then volcanism might still be active, and the chambers could currentlybe replenishing, which could trigger an eruption. / Heard Island är ett avlägset australiensiskt territorium som ligger i den södra delen av den Indiskaoceanen. Ön ligger i den centrala provinsen på Kerguelenplatån. På den nordvästra sidan av ön liggerLaurens-halvön, där modern vulkanism daterar sig till cirka 10 ka. Den främsta vulkaniska strukturenpå halvön är Mt Dixon där ingen aktivitet har registrerats, men som tros ha haft ett utbrott under desenaste hundra åren. Denna avhandling tillämpade metoden för kristallstorleksfördelning på tre tunnslipar frånLaurenshalvön. Proverna samlades in från en fonolit från Jacka valley, en tefrifonolit från basen av RedIsland cone och en tefrit öster om Cape Cartwright. Kristalldimensioner beräknades med ImageJ Fiji,dessa dimensioner korrigerades för 3D-dimensioner med CSDslice, och datat plottades medCSDcorrections. Mikrokristaller spårades med hjälp av backscattered electron images (BSE) ochhögupplösta skanningar av tunnslipen användes för att spåra fenokryster. Resultaten avkristallstorleksfördelningarna föreslog binär magmablandning via påfyllning i alla tre proverna. Dessavisade konkava former i alla plotter med branta sluttningar för mindre kristaller, följt av plattaresluttningar för större kristaller. De olika lutningarna på kurvorna föreslog två separatakristallisationsförhållanden: fenokryster kristalliserade långsamt i kammaren, och mikrokristallerkristalliserade relativt snabbt under eller efter utbrottet. Texturella skillnader i de tre proverna antyddeatt tefriten hade den längsta residenstiden och genomgick flest påfyllningshändelser, följt avtefrifonoliten och slutligen fonoliten. Slutligen, om påfyllning var mekanismen för att blandas underLaurenshalvön, så kan vulkanismen fortfarande vara aktiv, men för närvarande i ettpåfyllningsuppehåll.
34

Optimering av packkonfiguration inom varuflöde / Optimization of pre pack in the supply chain

Muhieddine, Tamara, Suneson, Julia January 2016 (has links)
Allt fler detaljhandelskoncerner möter problem med att optimera fördelning och påfyllning av produkter till butiker. Ledtiderna inom modeindustrin är långa och återförsäljarna måste planera sina inköp flera månader i förväg för de kommande säsongerna. Produkterna paketeras hos tillverkarna innan de skickas vidare till centrallagret. Beslut om packstorlekar tas i samband med inköpsordern. Genom att paketera flera lagerhållningsenheter (SKU) tillsammans ökar effektiviteten och kostnader i leveransflödet reduceras, samtidigt kan felfördelningskostnader uppstå. Detta examensarbete är utfört åt Venue Retail Group som är en ledande aktör i norden inom accessoarer, resetillbehör och skor. Syftet med examensarbetet är att finna de åtgärder inom packutformningen som skulle kunna generera ökad genomförsäljning för Venue Retail Groups egenproduktion av syntetväskor. I examensarbetet formuleras förpackningsproblemet som ett optimeringsproblem. En modell utformas för bestämning av optimal packkonfiguration som tillfredsställer varje butikskategoris prognostiserade efterfrågan med målet att minimera de totala kostnaderna. Genom kartläggning av produkternas varuflöde samt identifiering av kostnader relaterade till packkonfiguration föreslår examensarbetet en ändring av Venue Retail Groups befintliga packstrategi som kan uppnå en bättre genomförsäljning. / An increasing number of retail groups is facing problems with optimizing distribution and replenishment of products to serve stores. Lead times in the fashion industry are long and dealers often have to plan their purchases several months in advance for the coming seasons. The products are packed in production before they are sent to the central warehouse. Decisions about the pack configuration are made in connection with the purchase order. By packaging multiple stock-keeping units (SKUs) together, the efficiency increase and the costs in the supply chain can be reduced, while misallocation costs may arise. The master thesis is performed at the Venue Retail Group, which is a leading group in the Nordic region within the accessories, travel equipment and shoes. The objective of the paper is to identify the optimal pack configuration in order to generate increased turnover sales within the supply chain for own production synthetic bags. In this paper the pack problem is formulated as an optimization problem. A model is designed to determine the optimal packing order quantities that satisfy every store category's forecasted demand with the goal to minimize the total costs. By mapping product flow and identifying costs related to pack configuration the paper suggest a change of Venue Retail Groups existing pack strategy to achieve the objective.
35

JPEG 2000 and parity bit replenishment for remote video browsing

Devaux, François-Olivier 19 September 2008 (has links)
This thesis is devoted to the study of a compression and transmission framework for video. It exploits the JPEG 2000 standard and the coding with side information principles to enable an efficient interactive browsing of video sequences. During the last decade, we have witnessed an explosion of digital visual information as well as a significant diversification of visualization devices. In terms of viewing experience, many applications now enable users to interact with the content stored on a distant server. Pausing video sequences to observe details by zooming and panning or, at the opposite, browsing low resolutions of high quality HD videos are becoming common tasks. The video distribution framework envisioned in this thesis targets such devices and applications. Based on the conditional replenishment framework, the proposed system combines two complementary coding methods. The first one is JPEG 2000, a scalable and very efficient compression algorithm. The second method is based on the coding with side information paradigm. This technique is relatively novel in a video context, and has been adapted to the particular scalable image representation adopted in this work. Interestingly, it has been improved by integrating an image source model and by exploiting the temporal correlation inherent to the sequence. A particularity of this work is the emphasis on the system scalability as well as on the server complexity. The proposed browsing architecture can scale to handle large volumes of content and serve a possibly very large number of heterogeneous users. This is achieved by defining a scheduler that adapts its decisions to the channel conditions and to user requirements expressed in terms of computational capabilities and spatio-temporal interest. This scheduling is carried out in real-time at low computational cost and in a post-compression way, without re-encoding the sequences.
36

[en] COLLABORATIVE DEMAND PLANNING: INTEGRATION WITH IMPROVED OPERATIONAL PERFORMANCE / [pt] PLANEJAMENTO COLABORATIVO DA DEMANDA: INTEGRAÇÃO COM MELHORIA DA PERFORMANCE OPERACIONAL

PRISCILA MARTINEZ DE SOUZA 12 September 2013 (has links)
[pt] Este trabalho acadêmico tem como objetivo oferecer um guia de planejamento de demanda para uma indústria de médio porte por meio de colaboração de várias áreas dos processos decisórios, tais como departamentos chave da empresa, fornecedores e clientes. Propor metodologia formal para ajudar no balanceamento da oferta e demanda, promover a troca de informações dentro e fora da organização, otimizar o uso de recursos materiais e financeiros, e consequentemente, melhorar o resultado do retorno sobre o investimento. Observa-se no mercado que as pesquisas e práticas de planejamento colaborativo de demanda são direcionadas apenas para as grandes organizações, deixando assim as demais empresas sem referência. Logo, este trabalho tem a pretensão de contribuir com as empresas de médio porte, oferecendo soluções adaptadas para tratamento das causas das dificuldades e falhas de planejamento da demanda. A dissertação baseou-se em estudo de caso, dados de fontes primárias extraídos de sistemas de informação da empresa em estudo, entrevistas com funcionários envolvidos neste processo, visitas in loco para observação direta, e pesquisas bibliográficas que proporcionaram fundamento teórico. O foco da proposta de melhoria fundamenta-se nos conceitos e práticas de Sales and Operations Planning (SeOP) ou Planejamento de Vendas e Operações, como planejamento colaborativo interno para melhoria da conexão das áreas funcionais da empresa. O planejamento colaborativo externo para aperfeiçoamento da interface da empresa com fornecedores e clientes completa a proposta por meio dos conceitos e práticas adaptadas do Collaborative Planning, Forecasting and Replenishment (CPFR) ou Planejamento Colaborativo, Previsão e Reabastecimento. / [en] This academic work is intended to provide a guide for planning demand for a medium size industry through collaboration in various areas of decision making, such as key company departments, suppliers and customers. This Masters thesis proposes a formal methodology to assist in balancing supply and demand, promotes the exchange of information within and outside the organization, optimizes the use of material and financial resources and consequently improves the return on investments. It is observed in market research and planning practices thats collaborative demand is directed only to large organizations, thus leaving other companies without reference. Therefore, this work intends to contribute with midsize companies, offering solutions tailored to treat the causes of the difficulties and failures of demand planning. The dissertation was based on a case study data from primary sources drawn from the information systems of the company under study, interviews with officials involved in this process, site visits for direct observation, and literature searches that provided theoretical foundation. The focus of the proposed improvement is based on the concepts and practices of Sales and Operations Planning (SandOP), and collaborative planning to improve the internal connection of the functional areas of business. Collaborative planning for improving the external interface with the companys suppliers and customers complete the proposal through the concepts and practices adapted from the Collaborative Planning, Forecasting and Replenishment (CPFR).
37

Modèles de réapprovisionnement de stocks sous incertitudes et perturbations dans le contexte d’un e-détaillant / Inventory models subject to inaccuracies under the e-retailing context

Khader, Selma-Afakh 03 October 2013 (has links)
L’objet de cette recherche est la modélisation et l'étude de l'impact de la prise en compte des perturbations et des erreurs sur les politiques de réapprovisionnement pour un e-détaillant. Une des principales incertitudes en gestion de stock est l’écart entre la quantité en stock lue dans le système d’information et la quantité réellement disponible dans le système physique. A travers une étude empirique nous avons montré que l’impact de ce type d’erreurs est important dans le cas du e-détaillant. Dans ce contexte, le système d’information joue le premier rôle dans le processus de satisfaction de la demande puisque c’est sur la confrontation entre la demande du client final et les quantités figurant dans le Système d’Information que repose la promesse de vente. A l’exception de quelques contributions, les perturbations en gestion des stocks ont été principalement étudiées dans le contexte du détaillant. Nous avons étudié l’impact de ces perturbations sur la politique de stockage dans un contexte e-détaillant en faisant l’hypothèse d’une modélisation multiplicative des erreurs afin d’optimiser le profit du e-détaillant, et proposé deux modèles de réapprovisionnement, mono- et deux- périodes. Pour le premier, nous avons proposé une extension du modèle classique de vendeur de journaux au contexte de e-détaillant/fournisseur, avec un processus de demande sujet à des perturbations. Une étude analytique nous a permis de comparer l’impact de deux types de modélisation des erreurs, additive et multiplicative. Le deuxième modèle est une extension du premier au cas deux périodes. Avec sa résolution exacte, nous avons démontré que le comportement des quantités optimales était non monotone et qu’une politique myopique n’est pas optimale pour le cas multi-périodes. Grace à une étude numérique nous avons pu proposer des recommandations pour les managers, quant aux quantités à commander pour les deux périodes. Un troisième modèle de réapprovisionnement étudie l’impact des perturbations pour un problème multi-périodes avec minimisation des coûts et en considérant deux taux de service à atteindre, l’un sur la satisfaction des demandes et l’autre sur la satisfaction des ventes. Dans ce contexte, nous avons étudié et discuté plusieurs stratégies d’alignement dont réalisation d’inventaires et déploiement de technologie RFID. / The aim of this PhD research is to study the impact of the inventory inaccuracy issue on replenishment policies under the wholesaling / e-retailing context. The inventory inaccuracy is defined as a discrepancy between the quantity shown by the Informational System and the quantity actually Physically available for sales. Such discrepancy has as root many sources of errors such as execution, transaction, misplacement, supply unreliability or shrinkage errors. We provide empirical evidence on the wide presence of inventory inaccuracies through one case study of wholesaling organizations. In e-retailing context customers’ demands are remotely satisfied based on the inventory level shown in the information system. The main interest of the research community was about studying the inaccuracy under the retail context. After motivating our research empirically and by the literature review, we develop three inventory frameworks subject to inventory inaccuracies under the wholesaling / e-retailing context with different configurations of the stochastic errors describing the inaccuracy issue. The error configuration could be additive for some sources of inaccuracies such as transaction as well as multiplicative (also known as stochastically proportional) for other sources such as shrinkage. Our first inventory framework aims to extend single-period (Newsvendor) model to the e-retailing/wholesaling context subject to inaccuracy. In Addition, to providing managerial insights, we compare the behavior of the optimal ordering strategies under the additive and the multiplicative error settings. Our second inventory framework is an extension of the former to the case of two selling periods. By solving exactly the two-period problem, we show that the behavior of the optimal ordering quantities is not monotonic, and conclude that a myopic policy could not be optimal. Thanks to a numerical study, we derive some interesting managerial insights about the management of the error risk between the two selling periods. Thanks to the theoretical results of our second inventory framework, we propose a third framework dealing with the inventory inaccuracy issue under a multi-period setting by assuming cost minimizing as a target but also by considering two Cycle Service Level constraints to achieve, the former for the demand satisfaction and the latter for the sales commitment satisfaction. We provide a comprehensive numerical study by comparing several policies as making inspection and RFID deployment.
38

Effekter av ett informationsintensivt material- och produktionsstyrningssystem / Effects of a new material- and productionplanning system with a more intence flow of information.

Löthmyr, Jenny, Nilsson, Therése, Pirttilä, Tina January 2000 (has links)
<p>We were assigned to do this master thesis by Husqvarna AB who at the time for this thesis just had implemented a new material and production planning system called Replenishment system. Husqvarna AB wanted us to examine the effects of their new planning system to see if it was profitable or not. Husqvarna AB had for a time considered their delivery and supplier service to bee their biggest problem and they wanted to solve this problem by improving the communication with all involved actors in the logistic chain, which they hoped would result in a better mix of products in their warehouses. The aim of this report was therefor to analyze eventual effects for Husqvarna AB when changing from a traditional material- and production planing system to a more information intensive one. The result of this report showed effects on decreasing administrational routines and improved flexibility and lead-times. An increased information exchange and thereby a closer market control also improves the chances of a correct mix in stock which improves the lead-time to customer as the"correct"parts is in stock. These improvements must offcurse be considered together with the increased number of transports and the cost of the implementation in the organization.</p>
39

Effekter av ett informationsintensivt material- och produktionsstyrningssystem / Effects of a new material- and productionplanning system with a more intence flow of information.

Löthmyr, Jenny, Nilsson, Therése, Pirttilä, Tina January 2000 (has links)
We were assigned to do this master thesis by Husqvarna AB who at the time for this thesis just had implemented a new material and production planning system called Replenishment system. Husqvarna AB wanted us to examine the effects of their new planning system to see if it was profitable or not. Husqvarna AB had for a time considered their delivery and supplier service to bee their biggest problem and they wanted to solve this problem by improving the communication with all involved actors in the logistic chain, which they hoped would result in a better mix of products in their warehouses. The aim of this report was therefor to analyze eventual effects for Husqvarna AB when changing from a traditional material- and production planing system to a more information intensive one. The result of this report showed effects on decreasing administrational routines and improved flexibility and lead-times. An increased information exchange and thereby a closer market control also improves the chances of a correct mix in stock which improves the lead-time to customer as the"correct"parts is in stock. These improvements must offcurse be considered together with the increased number of transports and the cost of the implementation in the organization.
40

Two-Echelon Supply Chain Design for Spare Parts with Time Constraints

Riaz, Muhammad Waqas January 2013 (has links)
We consider a single-part, two-echelon supply chain problem for spare parts. The network consists of a single manufacturing plant, a set of service centers (SCs) and a set of customers. Both echelons keep spare parts using the base-stock replenishment policy. The plant behaves as an M/M/1 queueing system and has limited production and storage capacity. Demand faced by each SC follows an independent Poisson process. The problem is to determine optimal location-allocation and optimal base-stock levels at both echelons while satisfying the target service levels and customer preferences of SCs. We develop a mixed integer non-linear programming model and use cutting-plane method to optimize the inventory-location decisions. We present an exact solution procedure for the inventory stocking problem and demonstrate the limitations of using traditional inventory models like METRIC-like and Approximate in case of high utilization rates. We show the effectiveness of our proposed cutting-plane algorithm and provide important managerial insights for spare parts management.

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