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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.
91

Load balancing in multichannel data collection wireless sensor networks / Répartition de trafic équitable dans un réseau de capteurs sans fil multicanal dédié à la collecte de données

Tall, Hamadoun 14 May 2018 (has links)
Les Réseaux de Capteurs Sans Fil (RCSF) sont de plus en plus exploités par des applications diverses grâce à leur facilité de déploiement et d’auto-configuration. Les applications de collecte de données qui utilisent les RCSF ont souvent un profil convergecast : l’ensemble des données récoltées par tous les capteurs du réseau sont acheminées vers un puits de collecte, grâce à une communication multi-saut. Pendant l’acheminement des données des nœuds de collecte vers le puits, des goulots d’étranglement sont fréquemment observés, principalement au voisinage du puits. Cela est du à la congestion et au phénomène d’entonnoir couramment observé sur le trafic de données ayant un profile convergecast. Outre un risque accru de collision, cela entraîne le débordement des files d’attente des nœuds concernés conduisant à des pertes de données. Cette perte réduit le taux de livraison au puits entraînant une baisse du débit du réseau. Afin de réduire ces pertes et de permettre un meilleur taux de livraison au puits, le trafic doit être équitablement réparti au niveau de chaque saut pendant l’acheminement. Dans cette thèse, nous avons d’une part proposé S-CoLBA (Single channel Collaborative Load Balancing Algorithm), un protocole mono-canal de routage dynamique avec équilibrage de la charge. Sa métrique de routage est basée sur le délais moyen d’accès au medium radio par nœud. Chaque nœud choisit comme prochain saut à destination du puits, un de ses voisins ayant le délais d’accès le plus court. S-CoLBA intègre également une surveillance permanente des files d’attente des nœuds afin de prévenir la congestion et d’éviter le débordement de ces files. D’autre part, nous avons adapté S-CoLBA pour le rendre utilisable dans un réseau multicanal. Cette version du protocole s’appelle M-CoLBA (pour Mulitchannel CoLBA). M-CoLBA évite la congestion en équilibrant la charge grâce à une répartition du trafic au niveau de chaque saut du réseau. Dans un réseau multicanal, le problème de support de diffusion se pose. M-CoLBA introduit des périodes de synchronisations où tous les nœuds utilisent le même canal pour échanger les informations de routage. Ces périodes de synchronisation contribuent à allonger les délais de bout en bout des paquets. Nous avons ainsi optimisé M-CoLBA en "surchargeant" les acquittements des trames avec les informations de routage ( piggybacking) et les états des files d’attente. Cela évite de passer par des périodes de synchronisation pour diffuser ces informations. Cette version optimisée s’appelle ABORt ( Acknowledgement-Based opportunistic Routing protocol). Dans un cas de trafic de type convergecast, ABORt induit une diversité des routes prises par les données collectées, ce qui est bénéfique à la quantité de données transportées et à la robustesse de la solution. Les contributions ont été évaluées par simulation et expérimentation dans un réseau monocanal et multicanal. Les résultats montrent que nos contributions améliorent le taux de livraison des données au puits, optimisent le délais de bout en bout et réduisent la quantité de trafic de contrôle comparé à des solutions déjà existantes. / The popularity of wireless sensor networks (WSNs) is increasing due to their ease ofdeployment and auto-configuration capabilities. They are used in different applica-tion domains including data collection with convergecast scenarios. In convergecast,all data collected in the network is destined to one common node usually called thesink. In case of high carried traffic load and depending on the used routing policy,this many-to-one data collection leads to congestion and queue overflow mainly innodes located near the sink. Congestion and queue overflow reduce delivery ratiothat negatively affects the network efficiency.Wireless sensor nodes are resource constrained devices with limited buffers sizeto store and forward data to the sink. Introducing multichannel communication inWSNs helps to increase the carried traffic load thanks to allowing parallel data trans-mission and reduction of contention and interference. With high traffic load, thenumber of data packets travelling from leaf nodes towards the sink becomes higher.In case the routing scheme does not balance the traffic load, it will be unfairly dis-tributed between forwarding nodes. Thus, nodes that are in part of the routing will beoverloaded while others are less used. Overloaded nodes increase the risk of conges-tion and queue overflow leading to data loss that reduces the throughput. Therefore,we need to couple the routing protocols with traffic load balancing scheme in hightraffic load network scenarios.The goal of this thesis is to propose an efficient routing solution to prevent con-gestion and queue overflow in high data rate convergecast WSNs, in such a way, tooptimize data delivery ratio at the sink node.On the one hand, we proposed a single channel traffic load balancing routingprotocol, named S-CoLBA (Single channel Collaborative Load balancing routing).It relies on data queueing delay metric and best score (according to the value of themetric) next hop neighbors to fairly distribute traffic load in per hop basis in the net-work. Since the carried traffic load increases in multichannel communication, onthe other hand, we adapted our contribution to cope with multichannel WSNs andwe named it as Multichannel CoLBA (M-CoLBA). As broadcasting information isnot straightforward in multichannel, we optimize M-CoLBA to use piggybackingscheme for routing information sharing in the network. This enhanced version iscalled ABORt for Acknowledgement-Based opportunistic Routing protocol and re-lies on ACK frames to share routing information. Doing so helps to optimize dataframe end-to-end delay and to reduce the transmitted beacons in the network. ABORtfairly distributes traffic load in the network and avoids congestion and queue over-flow.We evaluated the performance of our contributions in both simulation using Con-tiki OS Cooja simulator and experiment (only for S-CoLBA) on TelosB motes. Ob-tained results in both simulation and experiment confirm the efficiency of our routingprotocols in term of packet delivery ratio and queue overflow compared to some ex-isting routing protocols in the literature.
92

Macroscopic modelling of hybridoma cell fed-batch cultures with overflow metabolism: model-based optimization and state estimation

Amribt, Zakaria 23 June 2014 (has links)
Monoclonal antibodies (MAbs) have an expanding market for use in diagnostic and therapeutic applications. Industrial production of these biopharmaceuticals is usually achieved based on fed-batch cultures of mammalian cells in bioreactors (Chinese hamster ovary (CHO) and Hybridoma cells), which can express different kinds of recombinant proteins. In order to reach high cell densities in these bioreactors, it is necessary to carry out an optimization of their production processes. Hence, macroscopic model equations must be developed to describe cell growth, nutrient consumption and product generation. These models will be very useful for designing the bioprocess, for developing robust controllers and for optimizing its productivity.<p>This thesis presents a new kinetic model of hybridoma cell metabolism in fed batch culture and typical illustration of a systematic methodology for mathematical modelling, parameter estimation and model-based optimization and state estimation of bioprocesses. <p>In the first part, a macroscopic model that takes into account phenomena of overflow metabolism within glycolysis and glutaminolysis is proposed to simulate hybridoma HB-58 cell cultures. The model of central carbon metabolism is reduced to a set of macroscopic reactions. The macroscopic model describes three metabolism states: respiratory metabolism, overflow metabolism and critical metabolism. The model parameters and confidence intervals are obtained via a nonlinear least squares identification. It is validated with experimental data of fed-batch hybridoma cultures and successfully predicts the dynamics of cell growth and death, substrate consumption (glutamine and glucose) and metabolites production (lactate and ammonia). Based on a sensitivity analysis of the model outputs with respect to the parameters, a model reduction is proposed. <p>In the next step, the effort is directed to the maximization of biomass productivity in fed-batch cultures of hybridoma cells based on the overflow metabolism model. Optimal feeding rate, on the one hand, for a single feed stream containing both glucose and glutamine and, on the other hand, for two separate feed streams of glucose and glutamine are determined using a Nelder-Mead simplex optimization algorithm. Two different objective functions (performance criteria) are considered for optimization; the first criterion to be maximized is the biomass productivity obtained at the end of the fed-batch culture, the second criterion to be minimized is the difference between global substrate consumption and the maximum respiratory capacity.<p>The optimal multi exponential feed rate trajectory improves the biomass productivity by 10% as compared to the optimal single exponential feed rate. Moreover, this result is validated by the one obtained with the analytical approach in which glucose and glutamine are fed to the culture so as to control the hybridoma cells at the critical metabolism state, which allows maximizing the biomass productivity. The robustness analysis of optimal feeding profiles obtained with different optimization strategies is considered, first, with respect to parameter uncertainties and, finally, with respect to model structure errors.<p>Finally, the overflow metabolism model is used to develop an extended Kalman filter for online estimation of glucose and glutamine in hybridoma cell fed-batch cultures based on the considered available measurements (biomasses (on-line), lactate and ammonia (on-line or off-line)). The observability conditions are examined, and the performances are analysed with simulations of hybridoma cell fed-batch cultures. Glutamine estimation sensitivity is enforced by minimizing a cost function combining a usual least-squares criterion with a state estimation sensitivity criterion. <p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
93

Monitoring stokové sítě ve městě Brně / Monitoring of the sewerage system in the city of Brno

Dvorský, Petr January 2019 (has links)
This thesis deals with the monitoring of the sewerage system in the city of Brno. In the research part, there is made an overview of the most used measuring equipment for the monitoring of the sewerage system – level meters, flowmeters, automatic samplers. The practical part is devoted to the monitoring of the sewerage system in Brno for partial evaluation of the benefits of the project „Reconstruction and completion of sewerage in Brno“, realized in 2012 – 2014. Measuring campaign has taken place from June to October 2017. In the course of the work, the instalation of measuring equipment and the collection of measured data was done. After finishing measuring campaign, the data were evaluated from different aspects – the number of overflows, the quantity of overflowing water, the dilution ratio and the quantity of discharged pollution. Then, the hydraulic and construction technical assement of the pipelines of sewer network and overflow chambers and assements of the quantity of the rainwater were made. The results of the evaluation were compared with the results of the previous monitoring campaingns and with the data obtained before the project has been realized. Based on this, the benefit of the project was determined.
94

Studie odkanalizování vybrané obce / Study of sewer network of selected municipality

Remešová, Terezie January 2019 (has links)
The main goal of this diploma thesis is the proposal of sewerage variants of local parts of village Pačlavice, which are villages Pornice and Lhota. For individual municipalities are proposed three partially different variants, which vary mainly in the way of wastewater draining and wastewater treatment. All three variants are evaluate from an economic and technical point of view and on the basis of evaluation is propose a variant, which is in my opinion, the most suitable for these municipalities. In the villages Pornice, Lhota and Pačlavice are proposed new delivery and gravity sections, associated objects of overflow chambers with pumping stations, independent overflow chambers or separate pumping stations that complement the existing combined sewer system to ensure the drainage of wastewater to wastewater treatment plant and following treatment of this water.
95

Numerické modelování přepadu vody přes přeliv / Numerical Modelling of Weir Overflow

Šilhánková, Lenka January 2020 (has links)
This thesis deals with the numerical modeling of water overflow over the front spillway. The aim of the thesis is to calculate various types of turbulent models and to assess the overflow coefficient on a sharp front spillway. The model was created in free software SketchUp, but the modeling itself was carried out in FLOW-3D software. The content of the work is a description of used software, design and calculation.
96

Tenkostěnný pravoúhlý přeliv bez bočního zúžení ovlivněný šířkou koryta / Full-width thin-plate rectangular weir influenced by channel width

Zmítko, Jakub January 2020 (has links)
The diploma thesis deals with the propagation of a weir (channel) width on the weir capacity. The influence rate is analyzed by laboratory measurements on models with a weir (channel) width of 0,02 m to a width of 0,50 m. Different heads are analyzed and different discharges that calculate the discharge coefficient. The results are compared with previous works, especially with the work of Kindsvater and Carter (1957) and of Schoder and Turner (1929), where the same procedures are used to calculate discharge coefficients. The thesis contains a theoretical introduction to the problem of thin-plate weirs and the problem of the formation of the boundary layer in the flow of liquid, following with the analytical part. In the analytical part, the results of measurements, their comparison, and evaluation are published. The work is completed with evaluation and recommendations.
97

Předčištění odpadních vod na stokové síti / Wastewater pretreatment at sewerage network

Doskočilová, Denisa January 2015 (has links)
ABSTARCT The aim of this thesis is to treat the problem of wastewater pretreatment on the sewer network with a focus on storm water overflow and their impact on waterways with regard to The Methodological Manual for Assessment of storm water overflow within uniform sewerage systems in urban areas. This work describes the legislation relating to storm water overflow and includes comparison with other countries. Furthermore, there is processed the outline of objects and equipment which can be used for wastewater pre-treatment in the sewer network. In the practical part of the thesis there is designed a new solution for the mobile spillway edge of the storm water overflow OK2A, which is located within the sewer network in Brno. In the practical part of the paper there is depicted the project documentation of newly designed equipment and objects. Water management companies, design offices, students and the general public can use this thesis as an inspiration.
98

Studie odkanalizování města Rokytnice nad Rokytnou / The study sewerage city Rokytnice nad Rokytnou

Došek, Jan January 2016 (has links)
This work deals with factual building, which is a sewerage in the town of Rokytnice nad Rokytnou. The aim of this work is to propose measures to reduce inflow of redundant water to the local wastewater treatment plant. A method chosen to achieve it is an assesment the most problematic location and making a plan. This work includes among other outputs from the primary exploration and a condition survey, hydrological analysis and designing of two measures. These designs are complemented by the calculation of investment costs and their comparison. Appendix to this work contains drawings and the sheets from condition survey.
99

Experimentelle Untersuchungen zum Einfluss physikalischer Bodeneigenschaften auf die Rillenerosion

Hieke, Falk 29 January 2010 (has links)
Der Einfluss bodenspezifischer Größen auf die Rillenerosion wurde in Überströmungsversuchen in einem eigens dafür konstruiertem Kleingerinne untersucht. Die Neigung des 2 m langen und 0,1 m breiten Gerinnes wurde dafür zwischen 2, 4 und 6 % variiert. Im Gerinne wurden zum einen natürliche Böden, zum anderen künstliche, aus Schluff und Sand gemischte Substrate mit 0,060 l*s-1, 0,125 l*s-1 und 0,300 l*s-1 überströmt. Die Körnung der natürlichen Böden reichte von stark schluffig bis sandig-lehmig, die der künstlichen Substrate von stark schluffig bis sandig. Die künstlichen Substrate wiesen im Gegensatz zu den natürlichen Böden keine Aggregierung auf und waren frei von organischer Substanz. Zu Beginn der Versuche wird der Boden zunächst flächig überströmt. Währenddessen bilden sich Mikrorillen auf der Gerinnesohle aus. Selektiver Sedimenttransport bewirkt die Akkumulation der nicht transportablen Fraktion auf der Bodenoberfläche, wodurch sich Rippel bilden. Über den Rippeln formen sich stehende Wellen im Abfluss. Die stehenden Wellen erzeugen Sohlschubspannungsspitzen auf die Gerinnesohle, welche zu verstärkter lokaler Erosion, zur Ausbildung von Mikrodepressionen und im weiteren zur Entstehung von Rillenköpfen führen. Die Rillenköpfe wandern entgegen dem Gefälle und hinterlassen Rillen, in denen sich der Abfluss konzentriert. In den Rillen können weitere Rillenköpfe entstehen. Anhand des Beginns der Rillenerosion, der Rillenkopfneubildungsrate, dem Erosionsfortschritt der Rillenköpfe, der Bestandsdauer der Rillenköpfe und der Sedimentkonzentration im Abfluss kann das Phänomen „Rillenerosion“ erfasst und quantifiziert werden. Diese erosionsspezifischen Kennwerte zeigen sich dabei in Abhängigkeit von bodenspezifischen Größen, wie der Lagerungsdichte, der Korngrößenzusammensetzung sowie der Aggregatgrößenverteilung und –stabilität. Aus den Korrelationsanalysen zwischen den bodenspezifischen Größen und den spezifischen Kennwerten der Rillenerosion leiten sich empirische Beziehungen ab. Diese Beziehungen sind nicht-linearerer und nicht-stetiger Natur. Parallel zu den Versuchen im Kleingerinne wurden Überströmungs- und Beregnungsversuche in einem Großgerinne durchgeführt. Die Projektion der laborativen Ergebnisse des Kleingerinnes auf das naturnahere Großgerinne zeigte dabei Parallelen.
100

Numerical hydraulic modeling of urban waste water collecting systems : Working Project at Chazelles-sur-Lyon, France

Genty, Stanislas January 2014 (has links)
Urban waste water collecting systems are designed to convey domestic, industrial and storm water. When sizing sewer network, heavy rainfall must be considered to provide the needed hydraulic capacity for collection. Maintenance is also required in order to avoid anomalies such as inflow, infiltration and unusual polluted discharges from Combined Sewer Overflows (CSOs). Inflow and infiltration decrease the treatment yield at the Waste water Treatment Plant (WWTP) and participate in hydraulic overloads and overflows. CSOs have a direct impact on the pollution of water bodies and must be strictly sized and monitored. Detecting sizing and maintenance anomalies is crucial to ensure public health and a good status of our natural environment. Today, numerical hydraulic models support consulting engineers in assessing overflows then in choosing the best technical and cost-effective scenario. The objectives of this paper are to review the dysfunctions of collecting system and to understand how a numerical hydraulic model is constructed, calibrated and then used to establish a Corrective Action Plan (CAP). My master thesis is based on a working project achieved at SAFEGE (Group SUEZ Environnement) in the Urban Hydraulics Department in Lyon (Rhône-Alpes, France) between September 2013 and February 2014. The paper will present some outcomes obtained from an Urban Hydraulic Project at Chazelles-sur-Lyon (Rhône-Alpes, France) in the South West of Lyon. Mike Urban is the software - developed by the company DHI Water- used for the numerical hydraulic modeling.

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