Dissertationen zum Thema „Lignin distribution“
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Reeves, Alison Dawn. „The distribution and behaviour of lignin in the estuarine environment“. Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237510.
Der volle Inhalt der Quelle寶詠恩 und Vivienne Valerie Claire Bucher. „Distribution of lignin-modifying enzymes among aquatic fungi and theirability to degrade lignocellulose substrates“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31243988.
Der volle Inhalt der QuelleAtadana, Frederick Williams. „Catalytic Pyrolysis of Cellulose, Hemicellulose and Lignin Model Compounds“. Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31251.
Der volle Inhalt der QuelleThe effect of HZSM-5 catalyst and NaOH pretreatment on the product distribution and bio oil properties from pyrolysis of cellulose, hemicellulose and lignin model compounds was investigated at 450 °C. NaOH pretreated and untreated cellulose was pyrolyzed on sand and the HZSM-5 catalysts; VPISU001 HZSM-5, BASF HZSM-5, and Sud-Chemie HZSM-5. The pyrolysis of cellulose on BASF and Sud-Chemie HZSM-5 catalysts increased the yields of the organic liquid fraction, total liquid and char while decreasing the gas yields. However the catalyst decreased the organic and char yields while increasing the water yields but there was no change in gas yields. The NaOH treatment caused a decrease in the organic and total oil yields relative to the control but the char yield increased. The change in gas yields was not significant. The characterization of the oils using FTIR and 13Câ nmr showed that, the VPISU001 HZSM-5 with and without NaOH pretreatment caused elimination of the levoglucosan fraction while increasing the aromatic fraction. The NaOH pretreated cellulose pyrolyzed on sand reduced the levoglucosan groups while increasing the aromatic fraction of the bio oil. In the hemicellulose studies, birchwood xylan and NaOH treated xylan samples were pyrolyzed on sand and VPISU001 HZSM-5 catalyst. The organic liquid yields were very low and ranged from 3.3 wt% to 7.2 wt%, the water yields ranged from 17.8-25.7 wt%, the char yield were 17.8-25 wt% and gas yield were 40.9-49.6 wt%. The HZSM-5 catalysts increased the water and gas yields and produced the lowest char yield. NaOH pretreatment produced the lowest water yield while the char yield was the highest. The combined effect of NaOH pretreatment and HZSM-5 produced the lowest organic yield and highest char yield. The FTIR and 13C-nmr analyses of the organic liquids showed that the HZSM-5 catalyst promoted the formation of aromatic products, while the NaOH pretreatment promoted the formation of aliphatic hydrocarbons. The combined effect of NaOH pretreatment and HZSM-5 catalyst seem to promote the formation of anhydrosugars. The main gases evolved were CO, CO2 and low molecular weight hydrocarbons. The HZSM-5 catalyst promoted CO formation while NaOH pretreatment promoted CO2. The HZSM-5 catalyst produced the highest yield of low molecular weight hydrocarbon gases. The lignin and model compounds studies involved using low molecular weight kraft lignin, guaiacol, and syringol which were pyrolyzed on sand and VPISU001 HZSM-5 catalyst at 450 °C. The kraft lignin pyrolysis produced low liquid and gas yields and high char yields. The HZSM-5 catalysts increased the water yield and decreased the organic liquid yield. NaOH pretreatment increased the char yield and decreased the liquid products. NaOH and the HZSM-5 catalyst together decreased the char and increased the gas yields. The 13C-nmr and FTIR analysis showed that NaOH pretreatment promoted the formation of mainly guaiacol while the HZSM-5 catalyst formed different aromatic components. NaOH pretreatment promoted the formation of more CO2 than CO whilst HZSM-5 catalyst promoted the formation of more CO than CO2. Methane formation was enhanced by NaOH pretreatment. Other hydrocarbon gases were however enhanced by the HZSM-5 catalysts. Pyrolysis of the model compounds on the HSZM-5 catalyst showed an increase in pyrolytic water. The HZSM-5 catalyst promoted demethylation in syringol pyrolysis as compared to guaiacol.
Master of Science
Morel, Oriane. „Characterization of the spatial distribution of lignins in plant cell walls using chemical reporters and Raman“. Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILS118.
Der volle Inhalt der QuelleLignin is a polyphenolic polymer of the cell wall involved in many aspects of growth and development in higher plants. As a major component of lignocellulosic biomass, it is also of economic interest. Although the biosynthesis of the lignin polymer is relatively well understood, we need to know more about how changes (quantity/structure) to other cell wall polymers (e.g., cellulose, hemicelluloses, pectins) affect lignin production. To provide more information on this question we implemented a two-phase approach based on the use of biological imaging. The first phase involved the development/improvement of different high-resolution complementary imaging techniques. We firstly developed a novel quantitative ratiometric approach (REPRISAL) based on the parametric/artificial intelligence segmentation of confocal microscopy images obtained by lignin chemical reporter bio-orthogonal chemistry. This methodology allowed us to precisely map the lignification capacity of different cell wall layers (cell corner, compound middle lamella and secondary cell wall) in Arabidopsis WT plants and the prx64 mutant. In a second development, we modified the REPRISAL segmentation algorithim thereby enabling it to be used to map relative cell wall lignin levels determined by the ratiometric safranin-O fluorescence technique. Finally, we used Raman imaging to compare the ability of three different multivariate analytical methods (unmixing, cluster analysis and orthogonal matching) to provide detailed spatial information about the distribution of different polymers in plant cell walls. In the second phase we used the developed/improved imaging techniques to analyse whether changes to cell wall hemicelluloses affect lignification in the Arabidopsis irx9 mutant. Our results demonstrated that changes in the distribution of cell wall hemicelluloses do indeed modify the lignification process, particularly in the younger parts of the plant floral stem. Targeted transcriptomics of selected cell wall genes suggested that the observed changes could be related to the induction of a defence response. Overall, the techniques developed within the framework of this thesis should prove valuable for future studies of cell wall dynamics. The results obtained on the irx9 mutant provide a novel insight into the dynamic relationships that exist between different polymers of the plant cell wall
Chedid, Fadia. „Determination of absolute molecular mass distribution and other structural properties of kraft lignin samples : Investigation using SEC in combination with MALDI-TOF-MS and Py-GC/MS“. Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-105449.
Der volle Inhalt der QuelleDria, Karl Jay. „Carbon and nitrogen distribution and processes in forest and agricultural ecosystems a study involving solid- and liquid-state NMR and pyrolysis GC/MS /“. Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1085700625.
Der volle Inhalt der QuelleTitle from first page of PDF file. Document formatted into pages; contains xv, 214 p.; also includes graphics (some col.). Includes bibliographical references (p. 194-206). Available online via OhioLINK's ETD Center
Sjöberg, John. „Characterization of chemical pulp fiber surfaces with an emphasis on the hemicelluloses“. Doctoral thesis, KTH, Fibre and Polymer Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3462.
Der volle Inhalt der QuelleMain, Oscar. „Optimising forage maize's digestible yield under contrasted environments“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASB019.
Der volle Inhalt der QuelleMaize stands as a pillar of the French forage system, with its yield and silage feeding value serving as key criteria for the registration of maize hybrid varieties in the official French catalogue. Previous research on this topic has revealed a direct correlation between silage feeding value and dry matter (DM) digestibility, which is, in turn, constrained by cell wall (CW) digestibility and significantly affected by water deficit. Studies on maize inbred lines have shown that under severe water deficit conditions, both DM and CW digestibilities increase. This increase correlates with a decrease in lignin content and changes in lignin distribution. However, it is noteworthy that breeding efforts have already fixed lignin content in hybrid varieties. Therefore, lignin content is unlikely to be a source of future digestibility improvement. To explore other CW targets and the impact of water deficit on these traits, this PhD study was conducted as part of the Carnot Plant2Pro INRAE-ARVALIS MAMMA MIA project. We grew a range of modern forage maize hybrids representative of the current S0-S1 (very-early to early flowering earliness) French market for two years under sixteen contrasted environmental conditions, including six in controlled irrigation conditions. First, we established a simple but robust stress index (SID) that considers the water deficit in the soil and the air temperature. This SID provided a key environmental ranking tool, highlighting severe stress due to high temperature that significantly impacted DM digestibility compared to moderate stress conditions. Secondly, to encompass a wide range of environmental conditions in biochemical quantifications, we developed several predictive near-infrared spectroscopy (NIRS) equations capable of robustly and accurately predicting fine cell wall traits and relationships, mirroring levels observed in laboratory experiments. While these equations prove sufficiently robust for use in selection programs, we emphasize the need for vigilance in accurately estimating prediction accuracy under stress conditions, particularly in equations applied to hybrid material where trait variation ranges are often limited. The core dataset of this work enabled a multiscale analysis, integrating agroclimatic, agronomic, biochemical, and histological traits, along with in sacco experimental data on cows. We proposed biochemical and histological traits to improve the quality of forage maize depending on stress intensity. We demonstrated that under severe stress, ear production decreases significantly, but DM digestibility can be maintained by increasing CW digestibility. This boost in CW digestibility was due to a reduction in p-hydroxycinnamic acid content, while lignin content remained stable, as anticipated. The significance of lignin distribution increased with the severity of stress, reaching an extreme threshold where biochemical parameters solely account for digestibility variations. This two-threshold model presents a window of opportunity located at the first threshold between non-stressed and moderately stressed environments, where the increased role of lignin distribution alongside biochemical traits enabled an increase in digestible yield. By controlling irrigation doses in the field under moderate drought conditions and integrating the SID into an irrigation management tool, farmers could exploit this window to increase productivity
Burlat, Vincent. „Étude immunocytochimique de la distribution ultrastructurale des lignines dans la paille de blé et de son influence sur le mode d'action des champignons ligninolytiques : application aux pâtes à papier“. Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10100.
Der volle Inhalt der QuelleSiochi, Emilie J. „Dilute solution studies of molecular weight distributions of nitrocellulose, modified lignins and PMMA graft polymers“. Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54423.
Der volle Inhalt der QuellePh. D.
Pariset, Claude. „Quantification et distribution des proteine-kinases camp-dependantes dans la lignee germinale male des mammiferes“. Paris 5, 1987. http://www.theses.fr/1987PA05S014.
Der volle Inhalt der QuelleDupuy, Franck. „Modélisation des distributions des lignes de courant et du champ de concentration dans les réacteurs électrochimiques“. Toulouse, INPT, 2003. http://www.theses.fr/2003INPT034G.
Der volle Inhalt der QuelleFernandez-Ramirez, Eder-Ernesto. „Optimisation du taux de compensation série d'une longue ligne de distribution : cas de l'Hydro-Québec : Abitibi Téminscamingue [sic] /“. Thèse, [Chicoutimi : Rouyn : Université du Québec à Chicoutimi] Université du Québec en Abitibi-Témiscamingue, 2006. http://theses.uqac.ca.
Der volle Inhalt der QuelleBibliogr.: f. 136-139. Document électronique également accessible en format PDF. CaQCU
Ouwayed, Nazih. „Segmentation en lignes de documents anciens : applications aux documents arabes“. Thesis, Nancy 2, 2010. http://www.theses.fr/2010NAN23001/document.
Der volle Inhalt der QuelleThe indexing of handwritten scanned documents poses the problem of lines segmentation, if it fails, disabling the following steps of words extraction and recognition. In addition, the ancient Arabic documents contain annotations in the margins, often composed of lines obliquely oriented. The detection of these lines is important as the rest and is a major challenge for the indexing of these documents. Thus, the segmentation described in this thesis involves the extraction of multi-oriented lines. For this problem, the bibliography has only rudimentary techniques based essentially on the projection of the document image along one direction, which be failed in the case of multi-oriented documents. Given this lack, we have proposed an adaptive approach that first locates the different orientation zones, then based on each local orientation to extract the lines. During my thesis, i particularly invested on the following points : - Applying an automatic paving using the active contour model (snake). - Preparation the signal of the projection profile by removing all pixels that are not needed in the orientation estimation. Then, implementation of all energy distributions of Cohen's class on the projection profile to find the best distribution that gives the orientation. - Applying some extension rules to find the oriented zones. - Extraction of lines by using an connected components follow-up algorithm. - Separation of overlapped and touched lines using the morphology of Arabic terminal letters
Abo, Ismail Yasser. „La commercialisation en ligne et l'exclusivité territoriale“. Thesis, Montpellier 1, 2010. http://www.theses.fr/2010MON10059.
Der volle Inhalt der QuelleThe E-commerce has caused a true commercial revolution. Due to its dematerialized and cross-border nature, it raises new interrogations in front of the lawyers about the impact of this particular type of commerce on the angles of the economic life. One of these important angles is the distribution network which divides the client on a geographical basis to the extent that the approved distributor has a monopoly of distributing the contracted products within a fixed territory. Thus, E-commerce may constitute a powerful barrier to the territorial exclusivity because it constitutes, by its very nature, a distribution “without boundaries”. This is why we went towards analyzing the impact of online sales on the territorial exclusivity. While treating this subject we will explore the means suggested to control the online sales in order to preserve the rights conferred by the territorial exclusivity. We will study in the first part the impact of online sales on the respect of the territorial exclusivity by the parties of exclusive distribution contract. At another stage, we will present in the second part an analytical study of the legal situation of third parties with regard to our subject, while distinguishing between the legal situation of the other distributors members in the same network on one hand, and the legal situation of the parties involved in online parallel sales on the other hand
Heazel, Thomas Edward. „Cell wall sulfur distribution in sulfonated southern pine latewood“. Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/5786.
Der volle Inhalt der QuelleLu, Liping Simonot-Lion Françoise. „Performances and quality of service of PLC networks for MV and LV distribution systems“. Vandoeuvre-les-Nancy : INPL, 2006. http://www.scd.inpl-nancy.fr/theses/2006_LU_L.pdf.
Der volle Inhalt der QuelleThèse soutenue en co-tutelle. Titre provenant de l'écran-titre. Bibliogr.
Ouwayed, Nazih. „Segmentation en lignes de documents anciens : applications aux documents arabes“. Electronic Thesis or Diss., Nancy 2, 2010. http://www.theses.fr/2010NAN23001.
Der volle Inhalt der QuelleThe indexing of handwritten scanned documents poses the problem of lines segmentation, if it fails, disabling the following steps of words extraction and recognition. In addition, the ancient Arabic documents contain annotations in the margins, often composed of lines obliquely oriented. The detection of these lines is important as the rest and is a major challenge for the indexing of these documents. Thus, the segmentation described in this thesis involves the extraction of multi-oriented lines. For this problem, the bibliography has only rudimentary techniques based essentially on the projection of the document image along one direction, which be failed in the case of multi-oriented documents. Given this lack, we have proposed an adaptive approach that first locates the different orientation zones, then based on each local orientation to extract the lines. During my thesis, i particularly invested on the following points : - Applying an automatic paving using the active contour model (snake). - Preparation the signal of the projection profile by removing all pixels that are not needed in the orientation estimation. Then, implementation of all energy distributions of Cohen's class on the projection profile to find the best distribution that gives the orientation. - Applying some extension rules to find the oriented zones. - Extraction of lines by using an connected components follow-up algorithm. - Separation of overlapped and touched lines using the morphology of Arabic terminal letters
Ouwayed, Nazih. „Segmentation en lignes de documents anciens : application aux documents arabes“. Phd thesis, Université Nancy II, 2010. http://tel.archives-ouvertes.fr/tel-00495972.
Der volle Inhalt der QuelleŠirůček, David. „Vliv aplikace lignitu na distribuci organického uhlíku v půdě“. Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401883.
Der volle Inhalt der QuelleLefort, Romain. „Contribution des technologies CPL et sans fil à la supervision des réseaux de distribution d'électricité“. Thesis, Poitiers, 2015. http://www.theses.fr/2015POIT2253/document.
Der volle Inhalt der QuelleEstablishing a supervisory infrastructure allows a better smart management than an expensive strengthening of distribution network to respond to new constraints at the energies control (Consumption, REN, EV ...). To transmit data, Power Line Communication (PLC) technologies present an advantage in this context. In fact, it enables a superposition of High Frequency (HF) signals on electrical signal 50/60 Hz. However, electric networks have not been developed to this application because of difficult propagation conditions. This research work makes a contribution to develop a simulation platform in objective to transmit data to 1 MHz. In first time, each network element is studied singly and in second time, together, to estimate "Outdoor PLC" transmission performance. The first element studied is the networks variation in function of frequency and time. Several 24h disturbance measurements on LV customers are presented. The second element is the transformers which established connection between Medium Voltage (MV) and Low Voltage (LV). The proposed modeling method is based on a "lumped model" and a "black box model". These models are applied to a 100 kVA H61 transformer most commonly used by French distribution system operator in rural and suburban networks. The third element is the power line used in MV and LV networks. The proposed modeling method is based on a "cascaded model" from the theory of transmission line. This model is applied to one power line used in LV underground network. Each model is obtained from various impedance measurements. To complete, an introductory study on mobile radio communication is performed to remote network distribution
Kaddour, Mohsen. „Contribution à la modélisation d'un coupleur actif à onde lente en lignes de transmission à contact métal-semiconducteur“. Toulouse, INPT, 1987. http://www.theses.fr/1987INPT034H.
Der volle Inhalt der QuelleNoumir, Zineb. „Etude de la qualité de l'eau potable dans un réseau de distribution par apprentissage statistique“. Troyes, 2012. http://www.theses.fr/2012TROY0033.
Der volle Inhalt der QuelleSafety systems supply drinking water is essential for public health. A water distribution network typically consists of plants, water towers, tanks, pumps etc. This type of infrastructure is particularly difficult to protect and monitor. Chlorine injected into manufacturing facilities has a double interest. It is first and foremost a powerful oxidant that inactivates viral or bacterial agents. It is also a tracer of the water quality and the integrity of the distribution network, since the presence of a contaminant in the network causes an immediate abnormal consumption of chlorine. This second point is the main focus of this thesis. The objective of this thesis is to detect the presence of a contaminant in the network, and provide a classification of the type of contaminant, so that the operator takes appropriate operational decisions. Due to the complexity of studied networks and diversity of substances contaminants, implementation of parametric models cannot unfortunately be exploited. The statistical learning methods can circumvent these difficulties. Thus, this thesis is structured into two main research topics, which are multiclass classification and detection by learning, studied in the light of measurements from chlorine sensors for real-time implementation
Do, Phai Duy. „Quantifying organic carbon fluxes from upland peat“. Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/quantifying-organic-carbon-fluxes-from-upland-peat(f66901b0-b930-469e-8c33-2e480c4becd1).html.
Der volle Inhalt der QuelleNguyen, The Vinh. „Gestion et conversion électrique dans une architecture distribuée d'énergies renouvelables“. Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0082/document.
Der volle Inhalt der QuelleManaging the distribution of electrical energy from renewable sources such as solar and wind energy is a technological barrier to improve performance and stability of the whole process of transfer of energy sources. Thus, research on power lines used as communication media are very promising for the facility management of small and middle powers with many generators, not necessarily initially designed in a process reliability. In addition, this new option allows management to improve performance and stability in the overall process of energy transfer. This study is particularly directed to a distributed parallel management for photovoltaic and / or multi-generators including other technologies such as wind, for example connected to a DC network also serves as a communication such as PLC system architecture. The PLC, using the modulation technique, allows the transfer of information such as temperature, the instantaneous power, the self-test etc. ... needed to optimize the energy production. The aim of this work is the study of a CPL solution designed to work on HVDC bus connecting renewable energy production systems. Circuits developed for the CPL will be considered as interfaces between the DC-DC converter and smart HVDC bus. They will be based on a hardware part consists of a transceiver interface incorporating a modulation-demodulation on the HVDC bus and a signal processor which processes the information exchanged between the various input sensors and monitoring
Geffroy, Anne-Gaëlle. „Splendeurs et misères des DRMs dans la distribution de musique en ligne : une analyse économique“. Phd thesis, École Nationale Supérieure des Mines de Paris, 2009. http://pastel.archives-ouvertes.fr/pastel-00005216.
Der volle Inhalt der QuelleLu, Liping. „Performances and quality of service of PLC networks for MV and LV distribution systems“. Electronic Thesis or Diss., Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL080N.
Der volle Inhalt der QuelleDans cette thèse, nous nous intéressons à la problématique liée à la communication numérique sur courant porteur dans l’objectif de fournir une infrastructure de communication qui permet la surveillance et le contrôle de la distribution et de la consommation de l’énergie. Ce travail a été effectué dans le cadre du projet européen REMPLI (Real-time Energy Management via Power Line and Internet) et a produit la spécification REMPLI PLC (Power Line Communication). Pour fournir une meilleure performance de la communication et effectuer le transfert de données en temps réel, en utilisant les réseaux électriques de moyenne tension et de basse tension, les problèmes principaux qui sont le routage dynamique de paquets de données, la gestion de la qualité de service et la notification des événement en temps réel, ont été traités. Nous avons développé un protocole de routage efficace pour s’adapter au changement dynamique de topologie du réseau électrique. Les performances de REMPLI PLC sont évaluées en utilisant des approches de simulation couplée avec des approches analytiques. Il est prouvé que la majorité des besoins applicatifs peuvent être satisfaite par REMPLI PLC. Nous avons proposé et implanté un nouvel “ordonnançeur de traffic” fournissant différents niveaux de qualité de service pour les applications. Des variantes de protocole ALOHA ont été proposées et évaluées afin de vérifier que les propriétés temps réel requises sur les notifications d’événements sont respectées
Villette, Sylvain. „Estimation de vitesse par analyse d'images acquises en filé : Application à la caractérisation de la distribution centrifuge de granules d'engrais“. Phd thesis, Université de Bourgogne, 2006. http://tel.archives-ouvertes.fr/tel-00496311.
Der volle Inhalt der QuelleCure, Morgane. „Concurrence à l'ère du numérique : exemples dans l'industrie hôtelière“. Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAG013.
Der volle Inhalt der QuelleThe growing digitalization of the economy has been disrupting the sellers distribution channels and has been favoring the emergence of new players: intermediation platforms. Meanwhile the traditional resale model gives way to an agency model and creates fertile ground for different cases of vertical restraints. The increasing digitalization of markets therefore pushes competition authorities to question and adapt their economic analysis of practices. This thesis focuses on the hotel industry which has been the subject of several specific cases, especially in Europe. Contractual practices such as price parity clauses imposed by online travel agencies to hotels have been the subject of numerous investigations. The first chapter of this thesis develops a model of structural demand estimation, allowing to assess the degree of substitution between the online distribution channels of a hotel chain, a crucial element in the market definition. Following the various competition cases, price parity clauses were partially or completely prohibited in several countries. In response, the platforms have developed new programs offering hotels an increased visibility in exchange of the voluntary compliance of price parity clauses. The second chapter of this thesis studies the effect of the adoption of this program on the prices set by the hotels separating the effects linked to the demand increase, thanks to visibility gains, from those linked to the clause compliance and fee increase linked to the program. This thesis also deals with the link between online travel agencies and another type of platforms: price comparison websites. The latter promise consumers the display of the most competitive offers on the market but the criteria used in the ranking algorithms are now debated. Moreover, their vertical integration into larger groups, which also have online travel agencies, raises questions about their impartiality. The third chapter studies the impact of the integration of Kayak and several online travel agencies (such as Booking.com) within the Booking Holding group on the ranking of hotels and sales channels displayed on the price comparison website
Boscher, Virginie. „Modélisation de la polymérisation en suspension du chlorure de vinyle : étude granulométrique en ligne par spectroscopie acoustique d'émulsions modèles stabilisées par les“. Thesis, Mulhouse, 2009. http://www.theses.fr/2009MULH3106.
Der volle Inhalt der QuelleThis study focuses on the action mechanisms of poly vinyl alcohol-based macromolecular surfactants on the stabilization of vinyl chloride (VCM)/water emulsions used for the suspension polymerization of VCM. Five “primary” PVA (PVA I) with high hydrolysis degrees ( between 73 à 88 %mol) and different polymerization degrees ( between 700 à 2500), as well as one “secondary” PVA (PVA II) with 45%mol, have been studied on a large concentration range [0-1000 ppm/water]. The interfacial tensions and the size distributions of ClBu/water emulsions have been determined as a function of time. An original technique of on-line granulometry: the ultrasound attenuation spectroscopy has been used. The PVA I with low and are the most efficient stabilizers. For each PVA I, a direct correlation between mean diameter of droplets and interfacial tension has been established. Moreover, the importance of the interface viscoelasticity has been demonstrated. Because of their low , PVA II are insoluble in water. Well-defined colloidal particles of PVA II and combinations PVA I/ PVA II have been prepared by coacervation. For a given total PVA concentration, these nanoparticles of diameter 150-200 nm lower more the interfacial tension, and the mean droplet diameters, than PVA I alone. A Pickering stabilization by nanoparticles can be considered, in addition to the steric stabilization provided by PVA I
Arres, Billel. „Optimisation des performances dans les entrepôts distribués avec Mapreduce : traitement des problèmes de partionnement et de distribution des données“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE2012.
Der volle Inhalt der QuelleIn this manuscript, we addressed the problems of data partitioning and distribution for large scale data warehouses distributed with MapReduce. First, we address the problem of data distribution. In this case, we propose a strategy to optimize data placement on distributed systems, based on the collocation principle. The objective is to optimize queries performances through the definition of an intentional data distribution schema of data to reduce the amount of data transferred between nodes during treatments, specifically during MapReduce’s shuffling phase. Secondly, we propose a new approach to improve data partitioning and placement in distributed file systems, especially Hadoop-based systems, which is the standard implementation of the MapReduce paradigm. The aim is to overcome the default data partitioning and placement policies which does not take any relational data characteristics into account. Our proposal proceeds according to two steps. Based on queries workload, it defines an efficient partitioning schema. After that, the system defines a data distribution schema that meets the best user’s needs, and this, by collocating data blocks on the same or closest nodes. The objective in this case is to optimize queries execution and parallel processing performances, by improving data access. Our third proposal addresses the problem of the workload dynamicity, since users analytical needs evolve through time. In this case, we propose the use of multi-agents systems (MAS) as an extension of our data partitioning and placement approach. Through autonomy and self-control that characterize MAS, we developed a platform that defines automatically new distribution schemas, as new queries appends to the system, and apply a data rebalancing according to this new schema. This allows offloading the system administrator of the burden of managing load balance, besides improving queries performances by adopting careful data partitioning and placement policies. Finally, to validate our contributions we conduct a set of experiments to evaluate our different approaches proposed in this manuscript. We study the impact of an intentional data partitioning and distribution on data warehouse loading phase, the execution of analytical queries, OLAP cubes construction, as well as load balancing. We also defined a cost model that allowed us to evaluate and validate the partitioning strategy proposed in this work
Dupou, Laurence. „Contribution a l'etude de la dynamique et de la distribution laterale des lipides dans les membranes plasmiques de cellules eucaryotes“. Toulouse 3, 1987. http://www.theses.fr/1987TOU30043.
Der volle Inhalt der QuelleLu, Liping. „Performances and quality of service of PLC networks for MV and LV distribution systems“. Thesis, Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL080N/document.
Der volle Inhalt der QuelleDans cette thèse, nous nous intéressons à la problématique liée à la communication numérique sur courant porteur dans l’objectif de fournir une infrastructure de communication qui permet la surveillance et le contrôle de la distribution et de la consommation de l’énergie. Ce travail a été effectué dans le cadre du projet européen REMPLI (Real-time Energy Management via Power Line and Internet) et a produit la spécification REMPLI PLC (Power Line Communication). Pour fournir une meilleure performance de la communication et effectuer le transfert de données en temps réel, en utilisant les réseaux électriques de moyenne tension et de basse tension, les problèmes principaux qui sont le routage dynamique de paquets de données, la gestion de la qualité de service et la notification des événement en temps réel, ont été traités. Nous avons développé un protocole de routage efficace pour s’adapter au changement dynamique de topologie du réseau électrique. Les performances de REMPLI PLC sont évaluées en utilisant des approches de simulation couplée avec des approches analytiques. Il est prouvé que la majorité des besoins applicatifs peuvent être satisfaite par REMPLI PLC. Nous avons proposé et implanté un nouvel “ordonnançeur de traffic” fournissant différents niveaux de qualité de service pour les applications. Des variantes de protocole ALOHA ont été proposées et évaluées afin de vérifier que les propriétés temps réel requises sur les notifications d’événements sont respectées
Ibn, Taarit Kaouther. „Contribution à l'identification des systèmes à retards et d'une classe de systèmes hybrides“. Phd thesis, Ecole Centrale de Lille, 2010. http://tel.archives-ouvertes.fr/tel-00587336.
Der volle Inhalt der QuelleRelaza, Théodore Jean Richard. „Sécurité et disponibilité des données stockées dans les nuages“. Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30009/document.
Der volle Inhalt der QuelleWith the development of Internet, Information Technology was essentially based on communications between servers, user stations, networks and data centers. Both trends "making application available" and "infrastructure virtualization" have emerged in the early 2000s. The convergence of these two trends has resulted in a federator concept, which is the Cloud Computing. Data storage appears as a central component of the problematic associated with the move of processes and resources in the cloud. Whether it is a simple storage externalization for backup purposes, use of hosted software services or virtualization in a third-party provider of the company computing infrastructure, data security is crucial. This security declines according to three axes: data availability, integrity and confidentiality. The context of our work concerns the storage virtualization dedicated to Cloud Computing. This work is carried out under the aegis of SVC (Secured Virtual Cloud) project, financed by the National Found for Digital Society "Investment for the future". This led to the development of a storage virtualization middleware, named CloViS (Cloud Virtualized Storage), which is entering a valorization phase driven by SATT Toulouse-Tech-Transfer. CloViS is a data management middleware developped within the IRIT laboratory. It allows virtualizing of distributed and heterogeneous storage resources, with uniform and seamless access. CloViS aligns user needs and system availabilities through qualities of service defined on virtual volumes. Our contribution in this field concerns data distribution techniques to improve their availability and the reliability of I/O operations in CloViS. Indeed, faced with the explosion in the amount of data, the use of replication can not be a permanent solution. The use of "Erasure Resilient Code" or "Threshold Schemes" appears as a valid alternative to control storage volumes. However, no data consistency protocol is, to date, adapted to these new data distribution methods. For this reason, we propose to adapt these different data distribution techniques. We then analyse these new protocols, highlighting their respective advantages and disadvantages. Indeed, the choice of a data distribution technique and the associated data consistency protocol is based on performance criteria, especially the availability and the number of messages exchanged during the read and write operations or the use of system resources (such as storage space used)
Le, Trung Dung. „Contribution des moyens de production dispersés aux courants de défaut. Modélisation des moyens de production et algorithmes de détection de défaut“. Thesis, Supélec, 2014. http://www.theses.fr/2014SUPL0009/document.
Der volle Inhalt der QuelleThis research focuses on the protection of MV distribution networks with Distributed Generators (DGs), such as wind farms or photovoltaic farms, etc. First, the state of art is carried out on fault behaviour of DGs, their impacts on protection system and the mitigation solutions. Next, algorithms are developed for directional relays without voltage sensors. Based on the symmetrical component method, these algorithms help the overcurrent protections to avoid the false tripping issue due to fault contribution of DGs. With the suppression of voltage sensors, such directional relays become cheaper in comparison with the traditional ones. Following the fault detection (the phase or residual current reaches the pick-up value) and depending on fault type (line-to-ground or line-to-line fault), the ratios between the variation (before and during fault) of negative-zero sequence or negative-positive sequence currents are calculated. From these ratios, a SVM (Support Vector Machines) classifier estimates the fault direction (upstream or downstream the detector). The classifier is trained beforehand from transient simulations. This survey shows good performances of the directional algorithms with different network parameters and different kinds of DGs. Such algorithms could be implemented in protections along the feeders in the future smart grids
Gambardella, Massimiliano. „Are telecommunication and media converging ? : the change in the production and distribution model of audio-video contents“. Thesis, Paris 10, 2014. http://www.theses.fr/2014PA100009/document.
Der volle Inhalt der QuelleRecently Creative Commons (CC ) licenses emerged. CC are a set of licenses which derive from the free/open source software world. The aim of CC licenses is to share the artistic works (videos , music, etc.) among users . This thesis is devoted to the study of videos under these licenses. In particular, the thesis focuses on three aspects of video production under CC licenses: the successful choice of the degree of openness of the license , the strategy to fund and conduct innovation and the way that determine the success of the projects. First, to investigate the appropriate choice among different degrees of openness in the CC licenses, we conducted an econometric analysis (quantitative approach) on video under CC licenses stored on the Internet Archive . The results suggest that in order to attract contributions of users, producers use different opening licenses based on their organizational status degrees. Then, to study the strategy to fund and manage the innovation generated by users, we conducted a case study (qualitative approach ) of a video under CC license, Big Buck Bunny. The results suggest that users can be used as a source of funding for the production and as partners to innovate. Finally, to study the path and the characteristics of projects that succeed, we created an agent-based model that is able to reproduce the stylized facts of the production of videos under CC license stored on an on-line platform
Cho, Ju-eun. „Impact de l'internet sur le cinéma : avec des exemples de trois pays : la France, les Etats-Unis et la Corée du Sud“. Thesis, Paris 8, 2016. http://www.theses.fr/2016PA080002.
Der volle Inhalt der QuelleSince the nineties, the spread of the internet and its devices has enabled many producers, distributors and moviegoers to change their attitudes towards movies. Our work has focused on demonstrating that the technical characteristics of the internet like the easy access, the hypertextuality and the interactivity can explain the changes noticed in the activities linked to the cinematographic field and the film itself.Although the reception of the internet by the public is extraordinarily fast, the market share of online film is still not really significant. Nevertheless, the growth of the digital generation and the simplification of techniques encourage us to believe in the potential of the internet.The distribution sector is the most influenced by the internet. The increased competition and the evolution of media chronology were inevitable. Despite the threat of easy piracy and the formation of the internal network of mega-media, it seems obvious that the internet will be a useful channel for independent films.Concerning the production area, all stages become participatory. The interaction between filmmakers and the audience and between the future audience and the works created new modes of movies as multi-stories movie, game movies, relay movies and movies with subsidiary texts.Glimpsed with the evocation of the technical features of the internet, the production and the distribution and the viewing of films are influenced by the internet in the sense of a popularization – which can result in public participation – and of immediacy. These two main effects were not synonym with a radical change in the area but, according to us, with a significant transformation in the cinematographic field
Cho, Ju-Eun. „Impact de l'internet sur le cinéma : avec des exemples de trois pays : la France, les Etats-Unis et la Corée du Sud“. Electronic Thesis or Diss., Paris 8, 2016. http://www.theses.fr/2016PA080002.
Der volle Inhalt der QuelleSince the nineties, the spread of the internet and its devices has enabled many producers, distributors and moviegoers to change their attitudes towards movies. Our work has focused on demonstrating that the technical characteristics of the internet like the easy access, the hypertextuality and the interactivity can explain the changes noticed in the activities linked to the cinematographic field and the film itself.Although the reception of the internet by the public is extraordinarily fast, the market share of online film is still not really significant. Nevertheless, the growth of the digital generation and the simplification of techniques encourage us to believe in the potential of the internet.The distribution sector is the most influenced by the internet. The increased competition and the evolution of media chronology were inevitable. Despite the threat of easy piracy and the formation of the internal network of mega-media, it seems obvious that the internet will be a useful channel for independent films.Concerning the production area, all stages become participatory. The interaction between filmmakers and the audience and between the future audience and the works created new modes of movies as multi-stories movie, game movies, relay movies and movies with subsidiary texts.Glimpsed with the evocation of the technical features of the internet, the production and the distribution and the viewing of films are influenced by the internet in the sense of a popularization – which can result in public participation – and of immediacy. These two main effects were not synonym with a radical change in the area but, according to us, with a significant transformation in the cinematographic field
He, Junkai. „Effective models and methods for stochastic disassembly line problems“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASE009.
Der volle Inhalt der QuelleStudying the disassembly of End-of-Life (EOL) products under uncertainty is becoming a hot research topic due to its benefits in reducing waste, saving non-renewable resources, and protecting the environment. Existing disassembly line works assume that stochastic information can be estimated as probability distributions or functions and most of them focus on stochastic disassembly line balancing problems. However, it is not always possible to obtain complete stochastic information due to a lack of historical data or excessive data volume, and the integrated disassembly line problem has been rarely addressed. In this thesis, four novel stochastic disassembly line problems with only partial stochastic information are investigated. The purpose is to propose effective models and solution methods for the considered problems. The main works of this thesis are:Firstly, a new stochastic disassembly line balancing problem (SDLBP) is studied to minimize the disassembly line cost under stochastic task processing times, given only the mean, standard deviation, and change-rate upper bound. For the problem, a chance-constrained model is first formulated, which is further approximately transformed into a distribution-free model by property analysis. Then, a fast heuristic is devised to solve the transformed model. Experimental results demonstrate that the distribution-free model can effectively solve the SDLBP with only partial stochastic information.In most existing literature, the cycle time that represents the maximum completion time among workstations is given. However, the disassembly line cost and cycle time are two conflicting performance criteria and impact mutually. In this thesis, a new bi-objective distribution-free SDLBP is studied to minimize the disassembly line cost and cycle time, where partial information of task processing times is required. For the problem, a bi-objective distribution-free model is constructed, and an improved ε-constraint method is designed. Numerical experiments show that the proposed method can reduce more than 90% computation rounds, compared with the basic ε-constraint method.Disassembly lines may generate pollution during separating EOL products, but this factor has not been considered in the previous SDLBP works. In this thesis, we study a new green-oriented distribution-free SDLBP to minimize the disassembly line cost and pollution emission simultaneously, in which workstations with different purchase prices can have different amounts of pollution emissions. For the problem, a new bi-objective model is formulated and a problem-specific ε-constraint method is devised. Experimental results show that selecting appropriately workstations can effectively reduce the pollution emission of a disassembly line. Besides, some managerial insights are discussed.The integrated optimization of disassembly line balancing and planning may enhance the efficiency of the disassembly system and reduce its expenses, which has not been studied before. In this thesis, an integrated stochastic disassembly line balancing and planning problem (ISDLBPP) is addressed to minimize the overall system cost, where component demands and component yield ratios are assumed to be uncertain. For the problem, a two-stage stochastic programming model is established and valid inequalities are devised to reduce the search space. Then, the sample average approximation (SAA) method and the L-shaped method are applied to solve the model. Numerical experiments show that the L-shaped method can save more than 60% computation time than the SAA method, without sacrificing solution quality
Bradu, Benjamin. „Modélisation, simulation et contrôle des installations cryogéniques du CERN“. Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00445840.
Der volle Inhalt der QuellePhan, Anh Tuan. „Power Systems Model Developments for Power Qality Monitoring : Application to Fundamental Frequency and Unbalance Estimation“. Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH8692/document.
Der volle Inhalt der QuelleRenewable energy, electricity and smart grids are core subjects as they have great environmental and societal impacts. Thus, generating, transporting and managing electric energy, i.e., power, still continue to drive a growing interest. In order to properly achieve these goals, several locks must be removed. Beyond issues related to the distribution architecture, the formalization of models, sizing tools, features and indicators, constraints and criteria, decentralized generation and energy management, power quality is central for the whole grid’s reliability. Disturbances affect the power quality and can cause serious impact on other equipment connected to the grid. The work of this thesis is part of this context and focuses on the development of models, indicators, and signal processing methods for power quality monitoring in time-varying power distribution systems.This thesis analyzes the power quality including several well-known features and their relevance. Power system models and signal processing methods for estimating their parameters are investigated for the purpose of real-time monitoring, diagnostic and control tasks under various operating conditions. Among all, the fundamental frequency is one of the most important parameters of a power distribution system. Indeed, its value which is supposed to be a constant varies continuously and reflects the dynamic availability of electric power. The fundamental frequency can also be affected by renewable energy generation and by nasty synchronization of some devices. Moreover, the power absorbed by loads or produced by sources is generally different from one phase to the other one. Obviously, most of the existing residential and industrial electrical installations with several phases work under unbalanced conditions. Identifying the symmetrical components is therefore an efficient way to quantify the imbalance between the phases of a grid. New state-space representations of power systems are proposed for estimating the fundamental frequency and for identifying the voltage symmetrical components of unbalanced three-phase power systems. A first state-space representation is developed by supposing the fundamental frequency to be known or to be calculated by another estimator. In return, it provides other parameters and characteristics from the power system. Another original state-space model is introduced which does not require the fundamental frequency. Here, one state variable is a function of the frequency which can thus be deduced. Furthermore this new state-space model is perfectly are able to represent a three-phase power system in both balanced and unbalanced conditions. This not the case of lots of existing models. The advantage of the proposed state-space representation is that it gives directly access to physical parameters of the system, like the frequency and the amplitude and phase values of the voltage symmetrical components. Power systems parameters can thus be estimated in real-time by using the new state-space with an online estimation process like an Extended Kalman Filter (EKF). The digital implementation of the proposed methods presents small computational requirement, elegant recursive properties, and optimal estimations with Gaussian error statistics.The methods have been implemented and validated through various tests respecting real technical constraints and operating conditions. The methods can be integrated in active power filtering schemes or load-frequency control strategies to monitor power systems and to compensate for electrical disturbances
Ha, Dinh Truc. „Line outage vulnerabilities of power systems : models and indicators“. Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT018/document.
Der volle Inhalt der QuelleThe vulnerability of electrical systems is one of the problems related to their complexity. It has received increasing attention from researchers in recent decades. Despite this, the fundamental phenomena that govern the vulnerability of the system are still not well understood.Understanding how the vulnerability of power systems emerges from their complex organization is, therefore, the main motivation of the present work. It proposes the definition of a standard method to assess the vulnerability of power systems and identify their most critical elements. The method enables a better understanding of the links between the topology of the grid and the line outage vulnerabilities.The first part of this research work offers a critical review of literature approaches used to assess system vulnerability. The results provided by these approaches for four IEEE test systems are confronted to a reference contingency analysis using AC power flow calculations. From these analyses, pros and cons of each approach are outlined. An improved method for assessment of system vulnerability to line outages is defined from this confrontation. It is based on DC load flow and graph theory.The second part proposes a new approach based on spectral graph theory and solving of DC power flow to identify how system vulnerability and critical components emerge from the power network topology
Seward, Shaya M. „Using Sediment Records to Determine Sources, Distribution, Bioavailability, and Potential Toxicity of Dioxins in the Houston Ship Channel: A Multi-proxy Approach“. Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7903.
Der volle Inhalt der QuelleMontpetit, Guillaume. „Les déterminants de la valeur dans le marché immobilier montréalais : étude appliquée aux lignes de distribution câblées, à la végétation et aux types de rue“. Mémoire, 2010. http://www.archipel.uqam.ca/3741/1/M11854.pdf.
Der volle Inhalt der QuelleDiallo, Ibrahima. „Évènements rares et gestion des actifs en contexte d'Hydro-Québec : prise de décision sous risque, incertitude et résilience“. Thèse, 2020. http://depot-e.uqtr.ca/id/eprint/9669/1/eprint9669.pdf.
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