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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.
1

ACCURACY OF ENERGY ESTIMATION FOR SMALL WIND FARMS BASED ON MESOSCALE WIND DATA

MengHan, Zhi January 2023 (has links)
As wind power is one of the main contributions to the energy transition, conducting the necessary production simulations during the development stage of a wind project can provide developers with an initial idea of its power generation potential. Existing wind farm production simulation studies have focused on data sources and time scales based on actual measurement wind data and annual production. This study analyses the accuracy of production simulations for two small wind farms using publicly available mesoscale wind data (NEWA, NORA3, CERRA) in WindPro software. A total of three simulations with different mesoscale data were performed for each wind farm. Annual energy production (AEP) and 12 monthly energy production (MEP) were compared to the actual data and AEP deviations and MEP root mean square error (RMSE) were calculated. Finally, the differences in accuracy between the three mesoscale data for the production simulations are discussed, as well as the consistency of the accuracy on the annual and monthly scales. The results show that the accuracy of all three mesoscale data for the Grollingbo wind farm is weak, with the AEP and MEP simulations from CERRA having the highest relative accuracy (+25.4%; 45.3). For the Räpplinge wind farm, NORA3 has the highest accuracy for both AEP and MEP simulations (+6.3%; 95.2).
2

On the probabilistic production simulation of electric power systems using equivalent load duration curve methods

Feng, Xiaoming January 1990 (has links)
No description available.
3

Aplikace APS systému pro plánování a rozvrhování výroby / APS system application for planning and scheduling

Zápotočný, Václav January 2014 (has links)
Master's thesis, made at the Institute of Production Machines, Systems and Robotics, aims, evaluate existing production of slope mowers manufactured by Dvořák – svahové sekačky s.r.o., and then perform data collection for obtaining complete technological processes of production. With the APS (Advanced Planning and Scheduling) system, simulate and design an optimized solution, with a view to significantly reduce the required storage current inventory of manufactured parts for assembly of that slope mower.
4

Echtzeitfähige energiesensitive Maschinensimulation

Witt, Marco 08 May 2014 (has links)
Energieeffizienz gewinnt als Wettbewerbs- und Kostenfaktor für die industrielle Produktion seit einigen Jahren immer mehr an Bedeutung und sollte bereits in der Produkt- und Prozessentwicklung bzw. -verbesserung berücksichtigt werden. Entsprechend zeigt der Beitrag, wie mittels Maschinensimulation auf der Basis empirischer Messdaten die Energieverbräuche für zukünftige Fertigungsprozesse durch eine integrierte Visualisierung abgeschätzt werden können.
5

Geographic Information System (GIS) Simulation of Emergency Power Production from Disaster Debris in a Combined Heat and Power (CHP) System

Ryals, Christopher Shannon 30 April 2011 (has links)
The objective of this study is to determine a predicted energy capacity of disaster debris for the production of emergency power using a combined heat and power (CHP) unit. A prediction simulation using geographic information systems (GIS) will use data from past storms to calculate an estimated amount of debris along with an estimated energy potential of said debris. Rather than the expense and burden of transporting woody debris such as downed trees and wood framing materials offsite, they can be processed (sorting and chipping) to provide an onsite energy source to provide power to emergency management facilities such as shelters in schools and hospitals. A CHP unit can simultaneously produce heat, cooling effects and electrical power using various biomass sources.This study surveys the quantity and composition of debris produced for a given classification of disaster and location. A comparison of power efficiency estimates for various disasters is conducted.
6

Contribution à l'évaluation économique des organisations productives : vers une modélisation de l'entreprise-compétences

Burlat, Patrick 09 January 1996 (has links) (PDF)
Dans un cadre de travail situe au carrefour des sciences économiques, des sciences de gestion et des sciences de l'ingénieur, cette thèse a pour objectif de contribuer à la construction de nouveaux modèles pour l'évaluation économique des organisations productives. La vision systémique habituelle de l'entreprise est en premier lieu traitée à travers l'approche économique néoclassique, le contrôle de gestion traditionnel, et le courant cybernétique. Mais nous montrons ensuite pourquoi le dosage des différents facteurs de production, l'analyse normative des couts, et le contrôle-commande qui prévalaient pour la description et l'évaluation d'une entreprise-facteurs, ne sont plus adaptés pour caractériser l'entreprise-compétences qui émerge du nouveau contexte industriel. Nous nous plaçons alors dans le cadre d'une théorie économique non standard caractérisée par une dimension organisationnelle forte en contexte de rationalité procédurale, dans le cadre d'une gestion par activités et par processus, et dans le cadre d'une approche plus cognitiviste du pilotage. Cette transition nous permet de développer des représentations de l'entreprise-compétences qui relient les performances aux connaissances, aux processus d'apprentissage, aux procédures de prises de décisions et aux chaines de rationalités individuelles et collectives associées a une interprétation méta-systémique de la hiérarchie. Ces modes de représentation sont ensuite formalises par un langage de modélisation et illustres par des expérimentations de simulation.
7

Diffusion Characterization of Coal for Enhanced Coalbed Methane Production

Chhajed, Pawan 01 August 2011 (has links)
This thesis explores the concept of displacement of sorbed methane and enhancement of methane recovery by injection of CO2 into coal, while sequestering CO2. The objective of this study was to investigate the diffusion behavior of San Juan Basin coal under single and competitive gas environments. The movement of gas in a coalbed reservoir starts in the coal matrix with diffusion towards the naturally occurring cleat network surrounding the matrix blocks. The gas production potential from coalbed reservoirs under different gas environments was, therefore, estimated by studying the diffusion behavior of the coal type. The results clearly showed that the rate of diffusion increases with decreasing reservoir pressure, the increase being exponential at low/very low pressure. As a final step, a simulation study was carried out using the experimental results to predict long-term gas production from coalbed reservoirs with and without CO2 injection. This was followed by a preliminary economic analysis in order to estimate the feasibility of enhanced recovery method by CO2 injection by calculating the net present value of a project with and without carbon credits. The results showed that it is possible to obtain significant improvement in methane recovery by CO2 injection. However, it becomes economically feasible only with carbon credits.
8

QUALIDADE DA MADEIRA E RENTABILIDADE NA PRODUÇÃO DE Pinus taeda L. VISANDO MÚLTIPLOS MERCADOS / WOOD QUALITY AND PROFITABILITY IN PRODUCTION OF Pinus taeda L AIMING MULTIPLES MARKETS

Lazzaretti, Douglas Seibert 14 December 2007 (has links)
This study aimed to analyze the behavior of simulations forest production in relation to the physical production and the market, considering costs and changes in prices paid to different assortments to knotwood and clearwood. To obtain the prognose of growth and production used the software FlorExcel® in module for Growth and Production. It was considered forest plantations located in Ponte Alta do Norte-SC. Two systems have been tested for thinning and clearcutting, both with thinning the 9, 12 and 16 years with 950, 700, 450 and 250 trees per hectare remaining, respectively. In the system of thinning I, the clearcutting was between 23 and 25 years with the addition of a further thinning in the year 20 with 250 trees per hectare remaining. In the system of thinning II, has simulated the clearcutting between 19 and 22 years. Three different systems pruning were simulated, where, in the first, only a pruning to 3 years with 2 meters high in all the trees, in the second system, pruning to 5 years with 4 meters high at 950 trees per hectare, in addition to pruning occurred in the first system and the third system, a pruning to 7 years with 6 meters high at 450 trees per hectare, Beyond of the pruning occurred in the systems I and II. There were simulations into three classes of site, divided into I - good, II- medium and III bad. It was analyzed for each simulation, 10 differentiation of price between knotwood and clearwood, in a scale ranging from 0 to 100% in increments of 10% in the clearwood price in relation of knotwood price. The used indicator for evaluating sceneries was the Internal Rate of Return (IRR). The realization of just one pruning resulted only in knotwood; in the realization of the second and third pruning, there was availability of clearwood in the 1st and 2nd log, respectively, suggesting an improving quality by realization of two and three pruning. For the classes of site I and II, the production system II with 3 pruning and clearcutting in the year 19, presents the highest IRR. Already in the class site III, is indicated the management system I with 3 pruning and shallow cut to 23 years for greater financial return. The results suggest that the mobilization of capital in the operations of pruning is advantageous for all classes of site, provided that the increase price of clearwood is at least 19% on knotwood. / Este trabalho teve como objetivo analisar o comportamento de simulações de produção florestal em relação à produção física e ao mercado, considerando custos de produção e variações de preços pagos aos diferentes sortimentos, conforme a presença ou não de nós nas toras. Para obtenção da prognose de crescimento e produção, utilizou-se o programa FlorExcel®, no módulo de Crescimento e Produção. Foram considerados plantios florestais localizados no município de Ponte Alta do Norte, Santa Catarina. Foram testados dois sistemas de desbastes e corte raso, ambos contaram com desbastes aos 9, 12 e 16 anos, com 950, 700, 450 e 250 árvores remanescentes por hectare, respectivamente. No sistema de desbaste I, o corte raso foi entre 23 e 25 anos, com adição de mais um desbaste no ano 20 e com 250 árvores remanescentes por hectare. No sistema de desbaste II, simulou-se o corte raso entre 19 e 22 anos. Três diferentes sistemas de podas foram simulados: no primeiro, apenas uma poda aos 3 anos, com 2 metros de altura na totalidade das árvores; no segundo sistema, poda aos 5 anos com 4 metros de altura em 950 árvores por hectare, além da poda ocorrida no primeiro sistema; e, no terceiro sistema, uma poda aos 7 anos, com 6 metros de altura em 450 árvores por hectare, além daquelas ocorridas nos sistemas I e II. Realizaram-se simulações para três classes de sítio, divididas em I- bom, II- médio e III- ruim. Foram analisadas, para cada simulação, dez diferenciações de preço entre toras com e sem nós (knotwood e clearwood), numa escala variando entre 0 e 100% em incrementos de 10% em relação a toras com presença de nós. Como indicador financeiro para avaliação dos cenários, foi utilizada a Taxa Interna de Retorno (TIR). A realização de apenas uma poda resultou somente em toras com nó; na realização da segunda e terceira podas, houve disponibilidade de clearwood na primeira e segunda toras, respectivamente, sugerindo ganho de qualidade com a realização de duas e três podas. Para as classes de sítio I e II, o sistema de desbaste II, com três podas e corte raso no ano 19, apresentou a maior TIR. Já na classe de sítio III, indicou-se a implantação do sistema de manejo I, com três podas e corte raso aos 23 anos para maior retorno financeiro. Os resultados permitem concluir que a mobilização de capital nas operações de poda apresenta-se vantajosa para todas as classes de sítio, desde que a valorização do preço de clearwood seja de, pelo menos, 19% sobre knotwood.
9

Developments of Tools Focused on Production Simulation to Improve Productivity in Shipyards Workshops

Bair, Frédéric 09 January 2009 (has links)
The goal of the thesis is to develop tools for improving shipbuilding workshops productivity. These tools have been tested on workshops of Aker Yards France shipyard, in Saint-Nazaire. The main chapter concerns the modelling of a workshop with the discrete-event simulation methodology. Production simulation is strongly used in some fields as automobile industry but is less used in shipbuilding. Indeed, the difficulty is that almost each piece to produce is unique. The objective is to show the importance of production simulation for such workshops. The modelled workshop is linked to a genetic algorithm to improve its productivity by optimizing its production sequence. Secondly a tool of creation and optimization of PERT networks has been created. The tool contains a graphical interface to easily handle networks and an optimization algorithm. This last one can minimize total cost of any project for a given total time. The tool has been linked to the modelled workshop. Consequently we get a PERT diagram of the workshop that can highlight critical activities. Finally, the last chapter explains the development of a tool to solve space allocation problems. Indeed space is often a critical point in many shipyards. Thanks to a user-friendly interface, the developed tool facilitates scheduling of these workshops. Furthermore it contains an optimization algorithm based on a heuristic approach to automate the planning process. In conclusion a set of efficient tools has been carried out with concrete applications on real workshops./Lobjectif de la thèse est de développer une série doutils qui permettent doptimiser la production dateliers de construction navale. Ces outils sont testés sur des ateliers du Chantier Naval Aker Yards France à Saint-Nazaire. Le chapitre principal traite de la modélisation dun atelier dit de PréPréFabrication sur le principe de la simulation de production à évènements discrets. La simulation de production est fortement utilisée dans certains domaines industrie automobile par exemple mais encore peu souvent en construction navale. En effet, la difficulté réside dans la diversité des pièces à produire. Lobjectif est de démontrer lintérêt de la simulation de production même dans ces ateliers où pratiquement chaque pièce à construire est unique. Latelier modélisé a été couplé avec un algorithme génétique pour améliorer sa productivité en optimisant la séquence de production. En second lieu, un outil de création et doptimisation des réseaux PERT a été créé. Loutil contient une interface graphique permettant une manipulation aisée des réseaux et un algorithme doptimisation. Ce dernier permet de minimiser le coût de réalisation dun projet pour un temps total fixé. En étant couplé avec le logiciel de simulation développé, une création automatique du diagramme PERT de latelier est créée, permettant de mettre clairement en évidence ses activités critiques. Finalement, le dernier chapitre de la thèse porte sur la création dun logiciel permettant de résoudre les problèmes de gestion de surface et de planification rencontrés dans certains chantiers. En effet, lespace au sol est un élément critique pour beaucoup dateliers de construction navale. Le logiciel développé, grâce à une interface conviviale et pratique, permet de faciliter grandement la planification. De plus, il contient un algorithme doptimisation basé sur des heuristiques afin dautomatiser le processus de planification. En conclusion, un ensemble doutils efficaces a été généré, avec des applications concrètes sur des ateliers réels.
10

Simulation et conception d'heuristiques efficaces pour un problème d'assemblage de planchers

Carle, Marc-André 13 April 2018 (has links)
Dans l'industrie de la fabrication de planchers de bois pour les remorques, la qualité d'un plancher est directement liée à la position relative des lattes de bois. Le procédé de fabrication actuellement en place chez notre partenaire industriel utilise une main-d'oeuvre abondante. Les planchers sont produits en continu et puisque les décisions de positionnement de lattes doivent se prendre très rapidement (chaque employé doit placer une latte à toutes les 1,5 seconde), même des employés d'expérience peuvent commettre des erreurs. Dans ce mémoire, nous proposons des méthodes rapides et efficaces pouvant être utilisées par un processus d'assemblage mécanique. Ces méthodes ont été utilisées pour assembler des planchers à l'aide de simulation par ordinateur. Par comparaison à l'assemblage manuel, qui produit des planchers ayant environ 5% de joints défectueux, nos méthodes d'assemblage produisent des planchers presque parfaits.

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