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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

Softwarová aplikace pro automatizovanou kontrolu objednaného materiálu podle výrobní dokumentace

Švestka, Marek January 2014 (has links)
Švestka, M. The software application for automated control of ordered material according to production documentation. Diploma thesis. Brno: Mendel University, 2014. The thesis deals with design and implementation of applications for structural composition monitoring of the switchgear.
2

SDN Benefits in a Legacy World

Chatzis, Vasileios January 2016 (has links)
This dissertation aims to explore how one could leverage Software Defined Network (SDN) and Network Function Virtualization (NFV) principles in order to realize Service Function Chaining (SFC) in a network. SDN is a new networking paradigm, which makes a network programmable through the use of a software entity called SDN controller. NFV is intended to enable deployment of virtualized network functions, therefore replacing existing hardware solutions. SFC provides the ability to route user traffic to one or more network functions in an orderly manner. SFC will potentially enable many use cases such as data providers being able to dynamically steer user traffic through a set of network functions such as rewall and loadbalancer. This study is based on a set of goals. These goals evolve around the implementation of a prototype that will enable a SDN controller to steer user traffic through a series of virtualized network functions (VNFs). An important part of the prototype setup is a Network Management Software (NMS) named BECS, which is developed by Packetfront Software AB. BECS is acting as an orchestrator on the network and has complete awareness of all the network devices present on the network it manages. One of the main requirements of the prototype is to enable BECS to communicate with a SDN controller. Once that has been achieved, BECS could provide the necessary information that the controller needs in order to create and install a set of forwarding rules in the SDN enabled switches of the network. All those steps are necessary in order to achieve SFC. In this prototype, SFC is realized by demonstrating the user specific traffic steering through a set of VNFs in a specific order, based on control messages originated from BECS. Until now, network architecture has been limited to the capabilities of the actual hardware equipment. SDN and NFV help us to overcome this limitation. Information needs to be available anywhere and at any time, in a reliable and secure way. To ensure that, we propose a new scheme of network architecture through our prototype solution. This solution intends to give the ability to network managers to re-shape their networks based on their needs by the use of SFC. / Denna avhandling syftar till att undersöka hur man kan utnyttja principer för Software Defined Network (SDN) och Network Function Virtualization (NFV) för att förverkliga Service Function Chaining (SFC) i ett nätverk. SDN är en ny typ av nätverksparadigm som gör ett nätverk programmerbart genom användning av en programvaruenhet som kallas SDN controller. NFV syftar till att möjliggöra utbyggnaden av virtualiserade nätverksfunktioner och på så sätt ersätta befintliga hårdvarulösningar. SFC bidrar till en förmåga att dirigera trafiken till en eller flera nätverksfunktioner på ett ordnat sätt. SFC kommer potentiellt att möjliggöra många användningsområden, t.ex. uppgiftslämnare som dynamiskt kommer kunna styra användartrafik genom en uppsättning av nätverksfunktioner såsom firewall och loadbalancer. Studien är baserad på en uppsättning av mål. Dessa mål kretsar kring genomförandet av en prototyp som gör det möjligt för en SDN-styrenhet att styra användartrafik genom en serie av virtualiserade nätverksfunktioner (VNFs). En viktig del av prototypinstallationen ar en Network Management Software (NMS) som heter BECS, vilken är utvecklad av Packetfront Software AB. BECS agerar som en Orchestrator på nätet och har fullständig kännedom om alla nätverksenheter som finns i nätverket som den förvaltar. Ett av de viktigaste kraven for prototypen är att göra det möjligt for BECS att kommunicera med en SDN controller. När detta uppnåtts kunde BECS lämna nödvändiga uppgifter som styrenheten behöver for att kunna skapa och installera en uppsattning vidarebefordrade regler iSDN-aktiverade switchar pa natet. Alla dessa åtgarder är nödvändiga for att uppnå SFC. I denna prototyp realiseras SFC genom att påvisa den användarspecifika trafikstyrningen genom en uppsättning VNFs i en viss ordning, vilket baseras på styrmeddelanden som härstammar fran BECS. Fram till nu har nätverksarkitektur varit begränsad till förmågan hos den faktiska hårdvaruutrustningen. SDN och NFV hjalper oss att undvika denna begränsning. Information måste finnas tillgänglig överallt och när som helst på ett tillförlitligt och säkert sätt. For att säkerställa detta föreslår vi med hjälp av vår prototyplösning ett nytt system for nätverksarkitektur. Denna lösning har för avsikt att ge network managers en förmåga att omforma sina nät baserat på deras behov av SFC-anvandning.
3

From Motion to Movements : Revelations by the Infant EEG

Nyström, Pär January 2008 (has links)
<p>The introduction of high density EEG (hd-EEG) nets for easy application on subjects of all ages has improved the possibilities to investigate the development of the infant neurophysiology. This dissertation consists of three studies (I – III) that investigate the visual motion system and mirror neuron system of the infant, and methodological sections that outline the bioelectrical background and the characteristics of the methods used. </p><p>Study I covers the maturation of cortical areas involved in motion perception in adults and infants using an ERP paradigm. Over three age groups (2, 3 and 5 month olds) the cortical activation increased dramatically. All infant groups showed significant activation when moving displays was contrasted to static displays on a video screen. The study shows that 5-month-old infants and older can be expected to process motion in a similar fashion as adults.</p><p>Study II covers the infant mirror neuron system (MNS). In adults the mu rhythm perturbations is considered a reliable measure of activation of the MNS. This study presented both a mu rhythm analysis and a ERP analysis to detect MNS activity in 6-month-olds and in adults. This study concludes that the infant MNS can be measured using ERPs and that the development of mu rhythm perturbations requires further study.</p><p>Study III focused on exploring the mu rhythm suppressions. 8-month-olds observed a live actor that performed goal directed reaches and non-goal directed hand movements. The results show robust mu rhythm perturbations time-locked to the grasping moment. The study concluded that the MNS activity is possible to evaluate by analysis of mu rhythm perturbations and that the MNS show mature characteristics at the age of 8 months.</p><p>In summary, Study 2 and 3 present new methods to investigate the infant mirror neuron system and shows that the infant MNS is active at 6 months of age. At 8 months of age the infant MNS show mature EEG responses to simple actions such as reaching. How the MNS development relates to the infants’ motor development, and how the MNS interacts with the development of social skills requires further studies that could benefit from the methods presented here.</p>
4

From Motion to Movements : Revelations by the Infant EEG

Nyström, Pär January 2008 (has links)
The introduction of high density EEG (hd-EEG) nets for easy application on subjects of all ages has improved the possibilities to investigate the development of the infant neurophysiology. This dissertation consists of three studies (I – III) that investigate the visual motion system and mirror neuron system of the infant, and methodological sections that outline the bioelectrical background and the characteristics of the methods used. Study I covers the maturation of cortical areas involved in motion perception in adults and infants using an ERP paradigm. Over three age groups (2, 3 and 5 month olds) the cortical activation increased dramatically. All infant groups showed significant activation when moving displays was contrasted to static displays on a video screen. The study shows that 5-month-old infants and older can be expected to process motion in a similar fashion as adults. Study II covers the infant mirror neuron system (MNS). In adults the mu rhythm perturbations is considered a reliable measure of activation of the MNS. This study presented both a mu rhythm analysis and a ERP analysis to detect MNS activity in 6-month-olds and in adults. This study concludes that the infant MNS can be measured using ERPs and that the development of mu rhythm perturbations requires further study. Study III focused on exploring the mu rhythm suppressions. 8-month-olds observed a live actor that performed goal directed reaches and non-goal directed hand movements. The results show robust mu rhythm perturbations time-locked to the grasping moment. The study concluded that the MNS activity is possible to evaluate by analysis of mu rhythm perturbations and that the MNS show mature characteristics at the age of 8 months. In summary, Study 2 and 3 present new methods to investigate the infant mirror neuron system and shows that the infant MNS is active at 6 months of age. At 8 months of age the infant MNS show mature EEG responses to simple actions such as reaching. How the MNS development relates to the infants’ motor development, and how the MNS interacts with the development of social skills requires further studies that could benefit from the methods presented here.
5

Dynamic Traffic Adjustment for End-to-End Proportional Differentiated Services on MPLS Networks

Hsieh, Chin-Chung 27 August 2004 (has links)
In this thesis, we propose a dynamic traffic adjustment scheme for end-to-end proportional differentiated services (EEPDS) on MPLS networks. When the Egress LSR (Label Switch Router) first observes that the proportional ratio of multiple flows could not be maintained, it will locate the performance bottlenecks by sending control messages to all the traversed LSR. In the proposed scheme, the identified bottleneck routers may have to drop the packets of traffic flows that do not require any QoS assurance (for example, the best-effort flows). Moreover, if dropping packets of the best-effort flows could not meet the goals of maintaining proportional ratios, the Ingress LSR would have to shape the traffic rates of sending flows proportionally based on the throughput values observed by the Egress LSR. Once a bottleneck router regains its sufficient bandwidth released by other traffic flows, it will send out control packets to notify the Ingress LSR to recover the original sending rates. Eventually, the proposed EEPDS mechanism can meet the goals of maintaining the proportional ratios by dynamically tuning the traffic flows. For the purpose of demonstration, we implement the EEPDS scheme by using MNS simulator. According to the experimental results, the EEPDS scheme has shown that it can meet the proportional ratios of multiple traffic flows even under severe network congestions, where multiple performance bottlenecks may occur. Finally, we observe that the processing overhead of the proposed EEPDS scheme is very small, since it is triggered only when the Egress LSR detects the situation of unsatisfied proportional ratios.
6

Génération de modèles numériques de surface et détection de changements 3D à partir d'imagerie satellite stéréoscopique très haute résolution / Digital surface model generation and 3D change detection from high resolution satellite stereoscopic imagery

Guérin, Cyrielle 18 February 2014 (has links)
L'imagerie satellite permet aujourd'hui l'acquisition d'un nombre croissant de données dont l'augmentation des résolutions spatiale et temporelle permet de caractériser de plus en plus finement une scène et son évolution. Dans ce contexte, les méthodes de détection des changements apparus entre deux scènes sont particulièrement étudiées. Elles sont généralement basées sur les différences radiométriques entre les images. Cependant, ces méthodes s'avèrent souvent peu robustes à des changements radiométriques non pertinents tels que ceux induits par la variation des conditions d'acquisition des images. L'objectif de cette thèse est ainsi de développer une méthode alternative, basée sur la recherche des changements d'élévation de la scène. L'élévation représente en effet une information pertinente et adaptée, notamment dans un contexte de détection des changements de type urbain (construction, destruction ou modification d'infrastructures). Pour répondre à des besoins en analyse d'image qui nécessitent des résultats rapides et fiables, la méthode que nous proposons est une chaîne de traitements complète et automatique basée sur l'exploitation de couples d'image satellites stéréoscopiques très haute résolution permettant la génération et la comparaison de Modèles Numériques de Surface (MNS). Afin de limiter les fausses alarmes de changements dues aux erreurs liées à la génération des MNS, une étape clé de cette thèse a consisté à augmenter la précision des MNS, notamment à travers la prise en compte des zones d'occlusions et de mauvaise corrélation. La méthode de génération des MNS à ainsi été améliorée et une technique innovante de fusion des deux MNS provenant du même couple d'images a été développée. La comparaison des MNS générés avec un MNS LiDAR montre que notre approche permet une nette augmentation de la qualité des MNS, les erreurs de corrélation sont réduites tandis que les zones d'occlusion sont précisément localisées.La méthode de détection des changements d'élévation est, quant à elle, basée sur une labellisation par optimisation des pixels du MNS différentiel calculé à partir des MNS produits à chaque date. Cette étape permet de mettre en évidence les vrais changements de la scène parmi le bruit résiduel des MNS. Les résultats obtenus sur différents sites testés montrent que plus de 80% des changements de taille supérieure à 15 pixels x 15 pixels (ou 100 m² avec des images très haute résolution) sont détectés par notre méthode, avec moins de 20% d'erreurs. Nous montrons cependant que ces résultats dépendent principalement du paramètre de régularisation de la détection des changements, qui contrôle le taux de fausses alarmes par rapport au taux de bonnes détections du résultat. / The growing amount of satellite data, increasingly resolved spatially and temporally, represents a high potential of information allowing the accurate characterization of the evolution of an area of interest. For this reason, automatic analysis techniques such as change detection methods are widely investigated. Most of them are based on radiometric changes between remote sensed optical images. These methods are however very sensitive to a significant number of irrelevant changes such as those due to the variation of the geometrical conditions between two different acquisitionsThe objective of this work is then to develop an alternative method based on the elevation change detection. The advantage of using the elevation is that this information is particularly relevant and well adapted in a context of urban monitoring where the elements of interest correspond to buildings that can be constructed, modified or destroyed between two dates.In order to satisfy new needs in image analysis which require quick and reliable results, our method is a complete and automatic processing flow based on the analysis of high resolution satellite stereoscopic couples and the generation of Digital Surface Models (DSM). Stereoscopic DSMs, however, generally suffer from a high number of correlation errors leading to false alarms in the final change detection map. One of the main contribution of this work consisted in increasing the DSM accuracy, especially through a better handling of the occlusion and miss-correlation areas. For this purpose, the image matching technique has been improved and all DSMs computed from the same stereoscopic couple are then fusioned through a new approach, based on an optimization method.The comparison between our DSM with a LiDAR-based DSM indicates that our method largely improves the DSM quality, the amount of correlation errors is decreased while the occlusion areas are accurately localized. The change detection method itself is based on the labelization of the pixels of the differential DSM computed from the DSMs generated at each date of interest. This step, performed through another optimization process, enables to bring forward the relevant changes among the residual noise of the DSMs. The results, obtained for several experimental areas, show that more than 80% of the changes larger than 15 pixels x 15 pixels (100 m² with high resolution images) are detected with our method, with less than 20% of false alarms. We also show that these results mainly depend on the regularization parameter which controls the balance between the amount of false alarms towards the amount of true detections in the final results.
7

Co-recalage de données hétérogènes 3D géo-référencées : contributions à la correction des relevés laser mobiles

Ridene, Taha 09 July 2010 (has links) (PDF)
Un développement considérable des bases de données cartographiques 3D à différentes échelles s'est produit ces dernières années. Il a été stimulé par de nombreux besoins et soutenu par de véritables progrès technologiques, et par une diversité d'approches en numérisation 3D. Nous considérons dans cette thèse un contexte de production de cartographie numérique basée sur la fusion de données hétérogènes 3D. Nous intégrons trois types de données : relevés avec laser fixe, relevés avec laser mobile issus d'un Système de Cartographie Mobile (MMS) et un Modèle Numérique de Surface (MNS). Les caractéristiques différentes de ces données muti-sources se traduisent par des incohérences et des déformations. Nous nous focalisons essentiellement sur les erreurs affectant les données du MMS. Nous décrivons une démarche innovante de correction de relevés laser terrestres en nous basant sur des données externes au système d'acquisition (MNS, BD ORTHO®...). Notre démarche est basée sur un recalage hétérogène de données 3D. Nous proposons trois variantes de recalage rigide de la famille des ICP. Nous proposons également une nouvelle méthode d'évaluation qualitative du recalage, ayant deux variantes. Celle-ci est basée sur l'extraction et la comparaison de primitives géométriques. Elle a été utilisée pour la comparaison des précisions des algorithmes de recalage développés. Les résultats expérimentaux issus de nos implémentations montrent des temps raisonnables pour une exploitation sur de grandes bases de données.
8

Génération de modèles numériques de surface et détection de changements 3D à partir d'imagerie satellite stéréoscopique très haute résolution

Guérin, Cyrielle 18 February 2014 (has links) (PDF)
L'imagerie satellite permet aujourd'hui l'acquisition d'un nombre croissant de données dont l'augmentation des résolutions spatiale et temporelle permet de caractériser de plus en plus finement une scène et son évolution. Dans ce contexte, les méthodes de détection des changements apparus entre deux scènes sont particulièrement étudiées. Elles sont généralement basées sur les différences radiométriques entre les images. Cependant, ces méthodes s'avèrent souvent peu robustes à des changements radiométriques non pertinents tels que ceux induits par la variation des conditions d'acquisition des images. L'objectif de cette thèse est ainsi de développer une méthode alternative, basée sur la recherche des changements d'élévation de la scène. L'élévation représente en effet une information pertinente et adaptée, notamment dans un contexte de détection des changements de type urbain (construction, destruction ou modification d'infrastructures). Pour répondre à des besoins en analyse d'image qui nécessitent des résultats rapides et fiables, la méthode que nous proposons est une chaîne de traitements complète et automatique basée sur l'exploitation de couples d'image satellites stéréoscopiques très haute résolution permettant la génération et la comparaison de Modèles Numériques de Surface (MNS). Afin de limiter les fausses alarmes de changements dues aux erreurs liées à la génération des MNS, une étape clé de cette thèse a consisté à augmenter la précision des MNS, notamment à travers la prise en compte des zones d'occlusions et de mauvaise corrélation. La méthode de génération des MNS à ainsi été améliorée et une technique innovante de fusion des deux MNS provenant du même couple d'images a été développée. La comparaison des MNS générés avec un MNS LiDAR montre que notre approche permet une nette augmentation de la qualité des MNS, les erreurs de corrélation sont réduites tandis que les zones d'occlusion sont précisément localisées.La méthode de détection des changements d'élévation est, quant à elle, basée sur une labellisation par optimisation des pixels du MNS différentiel calculé à partir des MNS produits à chaque date. Cette étape permet de mettre en évidence les vrais changements de la scène parmi le bruit résiduel des MNS. Les résultats obtenus sur différents sites testés montrent que plus de 80% des changements de taille supérieure à 15 pixels x 15 pixels (ou 100 m² avec des images très haute résolution) sont détectés par notre méthode, avec moins de 20% d'erreurs. Nous montrons cependant que ces résultats dépendent principalement du paramètre de régularisation de la détection des changements, qui contrôle le taux de fausses alarmes par rapport au taux de bonnes détections du résultat.
9

Caracterização microestrutural, mecânica e durante o processo de torneamento de aços ABNT 1045 e ABNT 1145 para avaliação do efeito do enxofre. / Microestructural, mechanical and during turning process characterization of ABNT 1045 and ABNT 1145 steels for the evaluation of the sulfur effect.

González Santos, Diego Fernando 20 May 2008 (has links)
O presente trabalho trata sobre a influência do teor de enxofre, em quatro aços com uma composição química similar (famílias ABNT 1045 e ABNT 1145), na microestrutura, nas propriedades estáticas, dinâmicas e nos processos de usinagem. Para esta análise foi feita uma caracterização microestrutural de cada material para determinar parâmetros tais como a fração de inclusões de sulfeto de manganês (MnS) e a fração volumétrica de perlita. Também foi feita uma caracterização mecânica que consistiu em ensaios estáticos mediante o ensaio de tração e dureza, e um ensaio dinâmico utilizando a barra de Hopkinson, com o objetivo de observar o comportamento das inclusões e do próprio material quando deformado com altas e baixas taxas de deformação. Para a caracterização durante a usinagem destes aços foram feitos ensaios de torneamento para avaliar as forças de corte e de avanço em velocidades de corte de 190, 110, 45 e 15 m/min. A rugosidade dos corpos-de-prova também foi medida. Os resultados obtidos nos ensaios de torneamento e da caracterização microestrutural foram analisados estatisticamente para observar variações do comportamento das forças de usinagem de cada aço sob diferentes condições de velocidade de corte, e tentar correlacionar esse comportamento com a microestrutura do material. Observou-se que o aço 1045-A apresentou forças de usinagem (força de corte e força de avanço) superiores que os demais aços, já o aço que apresentou menores forças de usinagem foi o aço 1145-B. Isto é apenas uma tendência, devido que não houve diferença estatística que avaliasse esse comportamento. Também se observou que a rugosidade é um parâmetro que depende mais da velocidade de corte que da distribuição e/ou morfologia das inclusões. Evidenciou-se a formação de aresta postiça de corte (APC) numa faixa de velocidades (15-50 m/min), o que influenciou na rugosidade para estas condições de velocidades. Verificou-se que o comportamento das inclusões em baixas taxas de deformação é de caráter frágil, entanto que em altas taxas seu comportamento é plástico e deforma junto com a matriz. / This work deals with the sulfur influence on the microstructure and on the static, dynamic and machining behavior of four steels with similar chemical composition. (ABNT 1045 and ABNT 1145). Microstructure characterization of the materials was performed in order to obtain the area fraction of the phases of perlite and sulfide inclusions. A mechanical characterization of the materials was also performed, consisting in a set of static (tension and hardness test) and dynamic tests (Split Hopkinson Pressure Bar Test) with the objective of observing the deformation behavior of the sulfide inclusions at low and high strain rates. Various machining tests were carried out at different cutting speeds, namely 190, 110, 45 e 15 m min-1, for obtaining the cutting forces during de machining process. After the machining tests, the roughness of the steels was also measured. Later on, the results of the different experiments were analyzed with statistical tools and then compared to establish a correlation between the cutting forces and microstructure. The higher cutting forces were registered for the 1045-A steel and the lower for the 1145-B steel. However, this was considered merely a trend given that no statistical difference was found to support any conclusion. It was also observed a stronger roughness dependency on the cutting speed than in the distribution and/or morphology of the inclusions. The steels were observed to form a built-up edge (BUE) in a range of cutting velocities of 15-50 m/min. This phenomenon affected the roughness for these cutting velocities. The behavior of the sulfide inclusions was observed to be brittle under low strain rates. On the other hand, under high strain rates, a plastic deformation behavior was observed with inclusions participating in the plastic flow of the metal matrix.
10

Estudo dos campos de tensão gerados por inclusões durante o processo de torneamento em aços ABNT 1045 utilizando o método dos elementos finitos. / A study of stress fields due to inclusions during turning of ABNT 1045 by using the finite element method.

Correa Saldarriaga, Pablo Alejandro 20 May 2008 (has links)
As inclusões de sulfeto de manganês (MnS) são compostos não-metálicos formados no aço pela reação entre o enxofre (S) e o manganês (Mn). A formação das inclusões de MnS durante o processo de produção do aço é esperada e desejada em aços onde a usinabilidade é uma característica importante. Na usinagem, as inclusões apresentam um efeito de concentração de tensão no aço facilitando a quebra do cavaco. Esse efeito está determinado por fatores como tamanho e forma das inclusões e a distribuição das mesmas na matriz metálica. Vários estudos experimentais têm sido realizados com relação a esses fatores, no entanto, não existem modelos numéricos consolidados sobre este tema. O foco deste trabalho foi estudar a relação entre a microestrutura de dois aços para construção mecânica (composição base ABNT 1045) e sua usinabilidade. Um modelo numérico foi proposto para estudar os campos de tensão gerados no aço durante os processos de corte, considerando os aspectos microestruturais (principalmente as inclusões de MnS). As tensões resultantes durante o torneamento foram simuladas com base em medições de força de avanço e de corte durante ensaios de usinagem. Foi obtida uma boa correlação entre o modelo numérico e os resultados experimentais. A análise numérica confirmou que as inclusões atuam como concentradores de tensão e que sua morfologia e distribuição influenciam na usinabilidade do material. / MnS inclusions are non-metallic compounds formed in steel due to chemical reactions between sulfur and manganese. The formation of MnS inclusions during steel production is generally expected and sometimes desired in steels for machining applications. During machining, the stress concentrating effect due to MnS inclusions is determined by factors such as their size, shape and distribution in the metallic matrix. Several experimental studies have been conducted in this area; nevertheless, there are no consolidated numerical models. The main objective of this work was to analyze the relationship between the microstructure of two steels (ABNT 1045) and their machinability. A numerical model was proposed to study the stress fields during the cutting process, considering the microstructural aspects of steels (mainly the MnS inclusions). Stresses during turning were simulated based on experimental measurements of cutting and feed forces. A good agreement between the numerical model and experimental results was observed. Numerical results confirm that MnS inclusions are stress concentrators and their morphology and distribution influence the materials machinability.

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