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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.
81

Zasílatelství námořních přeprav v ČR / Freight Forwarding for Maritime Shipping in CR

Hošková, Lucie January 2012 (has links)
The aim of this thesis is to provide a reader with the most complex information possible about the field of freight forwarding specialized in maritime shipping and about all the processes which take place in this area. This information could serve for a better orientation for trade or manufacturing companies which need to use maritime transportation and which do not have any or have only little experience with it. My aim is also to show, how to communicate with freight forwarding companies and what prices can be expected.
82

Design přepravníku dřeva s ručním ovládáním / Design of Timber Trailer with Manual Control

Paclík, Tomáš January 2013 (has links)
Subject of this thesis is design of a timber trailer with manual control. The designed timber trailer is one of the small machines that are used for a low–volume timber production. This timber trailer operates in a rough terrain – its outstanding feature is the ability to operate on steep slopes and overcome obstacles. The concept of the control system and the safe seating of a driver are contributions to the field of ergonomics. This machine is considerate of a forest environment because it minimizes formation of soil erosion. Easy washability and maintenance are other criteria of this proposal. The functional point of the design is firmed by the purposeful and aesthetic shaping which is unique in this category. Comparison of the proposal presented in this thesis with available machines demonstrates that work of designer is indispensable part of a machine development process.
83

Předávací most kolesového rypadla / Forwarding bridge of bucket-wheel excavator

Zeizinger, Lukáš January 2016 (has links)
The document deals inspecting forces of the structure. The task of diploma thesis is analyze the crane load and chech up the stress of steel construction. Perform stress analysis forwarding bridge of bucket-wheel excavator by using finite element method. Further assess the consequences resulting from the design modifications. The project was carried out with cooperation with NOEN, a.s.
84

Mécanismes de cache, traitement et diffusion de l'information dans les réseaux centrés sur l'information (ICN) / Cache, process and forward in Information-centric networking

Mekinda Mengue, Leonce 01 December 2016 (has links)
Ce travail de thèse s’est tout d’abord attaché à comprendre comment la prise en compte du temps de téléchargement, autrement dit, de la latence, lors de la mise en cache ou de la transmission de données pouvait contribuer aux performances du téléchargement dans les réseaux de caches dont ICN. Nous y introduisons un mécanisme distribué novateur qui décide de l’opportunité de conserver un objet en considérant que plus il a été long à télécharger plus intéressant il semble de le soumettre au cache sous-jacent. Nous montrons que ce nouveau mécanisme surpasse en de nombreux points l’état de l’art, que ce soit du point de vue de la réduction du temps moyen de téléchargement à partir de caches LRU, et de son écart-type (jusqu’à −60% ), que de celui de la vitesse de convergence vers ceux-ci. Dans une seconde phase, nous avons optimisé conjointement les fonctions de mises en cache et de distribution multi-chemin de requêtes de contenus. Troisièmement, nous avons étudié l’équité vis-à-vis des contenus au sein des réseaux de caches et plus particulièrement, d’ICN. Il en ressort que seule suffit une allocation équitable de la bande passante entre les contenus pour que l’équité d’ICN soit complète. Notre dernière contribution vise à aider au passage à l’échelle d’ICN dans contexte où deviennent réalités l’Internet des Objets et son espace de nommage illimité. Nous avons proposé une approche nouvelle au routage dans les réseaux centrés sur l’information, nommée AFFORD, qui combine apprentissage automatique et diffusion aléatoire. / This thesis investigates how making content caching and forwarding latency-aware can improve data delivery performance in Information-Centric Networks (ICN). We introduce a new mechanism that leverages retrieval time observations to decide whether to store an object in a network cache, based on the expected delivery time improvement. We demonstrate that our distributed latency-aware caching mechanism, LAC+, outperforms state of the art proposals and results in a reduction of the content mean delivery time and standard deviation of LRU caches by up to 60%, along with a fast convergence to these figures. In a second phase, we conjointly optimize the caching function and the multipath request forwarding strategies. To this purpose, we introduce the mixed forwarding strategy LB-Perf, directing the most popular content towards the same next hops to foster egress caches convergence, while load-balancing the others. Third, we address ICN fairness to contents. We show that traditional ICN caching, which favors the most popular objects, does not prevent the network from being globally fair, content-wise. The incidence of our findings comforts the ICN community momentum to improve LFU cache management policy and its approximations. We demonstrate that in-network caching leads to content-wise fair network capacity sharing as long as bandwidth sharing is content-wise fair. Finally, we contribute to the research effort aiming to help ICN Forwarding Information Base scale when confronted to the huge IoT era’s namespace.We propose AFFORD, a novel view on routing in named-data networking that combines machine learning and stochastic forwarding.
85

Service Aware Traffic Distribution in Heterogeneous A2G Networks

Tomic, David January 2019 (has links)
Airplanes have different ways to connect to the ground, including satellite air-to-ground communication (SA2GC) and direct air-to-ground communication (DA2GC). Each connection/link offers a different varying amount of transmission capacity over flight time. The traffic generated in the airplane must be forwarded/sent to ground over the available links. It is however not clear how the traffic should be forwarded so that traffic quality of service (QoS) requirements are met. The thesis at hand considers this question, and implements an algorithm handling the forwarding decision with three different forwarding schemes. Those consider traffic parameters in calculating a value assigned to each traffic flow, over a combination of priority, delay requirement and the number of times a traffic flow is dropped. The forwarding algorithm relies on proposed in-flight broadband connectivity (IFBC) network traffic and air-to-ground (A2G) link models, which aim at approximating the network environment of future IFBC networks. It is shown that QoS requirements of traffic flows in terms of packet loss and delay cannot be satisfied with capacities offered by current DA2GC and SA2GC technology. For a future scenario, with higher assumed link capacities, the QoS requirements are met to a higher extent. This is shown in lower packet loss and delay experienced by the respective traffic flows. Further, it is shown that the performance can be improved with specific forwarding schemes used by the forwarding algorithm. It is also investigated how a web cache can be used as a fallback technology. For this a required web cache hit rate is found, which should be high enough to offload the network with content served from the cache. Overall, the thesis aims at proposing an efficient traffic forwarding technique, and at giving insight into an alternative if this technique fails. / Flygplan har olika sätt att ansluta till marken, inklusive satellit-mark-kommunikation (SA2GC) och direkt luft till markkommunikation (DA2GC). Varje anslutning/länk erbjuder en annan varierande mängd överföringskapacitet under flygtid. Den trafik som genereras i flygplanet måste vidarebefordras/skickas till marken över de tillgängliga länkarna. Det är emellertid inte klart hur trafiken ska vidarebefordras så att trafiksäkerhetskvaliteten (QoS) uppfylls. Avhandlingen handlar om denna fråga och implementerar en algoritm som hanterar vidarebefordringsbeslutet med tre olika vidarebefordringssystem. De betraktar trafikparametrar vid beräkning av ett värde som tilldelas varje trafikflöde, över en kombination av prioritet, fördröjningskrav och antalet gånger ett trafikflöde tappas. Vidarebefordringsalgoritmen är beroende av föreslagna bredbandsförbindelser (IFBC) i nätverk och A2G-länkmodeller, som syftar till att approximera nätverksmiljön för framtida IFBC-nätverk. Det visas att QoS-krav på trafikflöden när det gäller paketförlust och fördröjning inte kan tillgodoses med kapacitet som erbjuds av nuvarande DA2GC- och SA2GC-teknik. För ett framtida scenario, med högre antagna länkkapacitet, uppfylls QoS-kraven i högre utsträckning. Detta visas med lägre paketförlust och fördröjning som upplevs av respektive trafikflöden. Vidare är det visat att prestanda kan förbättras med specifika vidarekopplingsscheman som används av vidarebefordringsalgoritmen. Det undersöks också hur en webbcache kan användas som en återgångsteknik. För detta hittas en obligatorisk webbcache-träfffrekvens, som bör vara tillräckligt hög för att ladda upp nätverket med innehåll som serveras från cacheminnet. Sammanfattningsvis syftar uppsatsen till att föreslå en effektiv trafiköverföringsteknik och att ge insikt om ett alternativ om denna teknik misslyckas.
86

Kooperatives Forwarding in drahtlosen Maschennetzen

Zubow, Anatolij 16 July 2009 (has links)
In der vorliegenden Arbeit werden praktische Protokolle für spontane drahtlose Multi-Hop Maschennetze vorgestellt, diese betrachten das drahtlose System ganzheitlich und berücksichtigen damit die Besonderheiten des drahtlosen Mediums, wie Fading, Interferenz sowie starke Signaldämpfung aufgrund von Entfernung bzw. Hindernissen. Interferenz ist eine Hauptursache für Paketverlust, Durchsatz und Latenz können durch die gleichzeitige Verwendung mehrerer interferenzfreier Kanäle verbessert werden. In Sensor- bzw. Community-Netzen kommt preiswerte und energiesparende Hardware zum Einsatz, die Verwendung zusätzlicher Antennen bzw. Radios ist deshalb nicht möglich. Andererseits werden aber zukünftige drahtlose Netze eine 100-mal höhere Knotendichte, verglichen mit heutigen Netzen, zeigen. Durch die Ausnutzung der im System inhärent vorliegenden Ressource Nutzer (Multi-User Diversität) werden durch Kooperation virtuelle Multi-Antennen und Multi-Radiosysteme aufgebaut. Aufgrund des großen Abstands zwischen den Knoten erreicht man erstens eine hohe räumliche Diversität und zweitens lassen sich damit auch negative Effekte, wie Interferenz zwischen benachbarten Kanälen, minimieren. Es werden Algorithmen sowohl für die Mediumzugriff- als auch die Routing-Schicht vorgestellt. Da keine spezielle physikalische Schicht notwendig ist, kann IEEE 802.11 verwendet werden. Schließlich kann auch auf die bereits heute verfügbare IEEE 802.11 Hardware, die nur eine Kanalumschaltzeit im Millisekundenbereich erlaubt, zurückgegriffen werden. Die zwei vorgestellten Protokolle eignen sich für Umgebungen mit hoher bzw. geringer Interferenz durch fremde WiFi-Netze. Bezüglich Durchsatz werden moderne Protokolle, wie DSR auf Basis von IEEE 802.11 und ETX-Metrik, um ein Vielfaches übertroffen, außerdem ist die Latenz klein und das TCP/IP-Protokoll kann unverändert verwendet werden. / In this work practical protocols are introduced for spontaneous wireless multi-hop mesh networks which contemplate the wireless system integrally and therefore take into account particular features of the wireless medium, like fading, interference as well as strong signal attenuation due to distance or obstacles. Interference is one of the main causes for packet loss. Throughput and latency can be improved by the simultaneous use of several non-interfering channels. In sensor or community networks inexpensive and energy-saving hardware is used. Additional antennas or radios are impossible therefore; on the other hand future wireless networks will show a 100 times higher node density in comparison with today''s networks, however. By the usage of the resource user (multi-user diversity), that is inherently present in the system virtual multi-antennas and multi-radio systems can be built up by cooperation. Firstly, a high spatial diversity can be achieved due to the large distance between the nodes and secondly, negative effects like interference can be minimized between neighboring channels. Algorithms are introduced both for medium access and routing layer. Since a special physical layer is not required IEEE 802.11 can be used. These days already available 802.11 hardware, which allows a channel switching time in milliseconds, is finally usable. The two protocols introduced here are suitable for environments with a high or low interference caused by foreign WiFi networks. Regarding their performance modern protocols like DSR based on 802.11 and ETX metric are surpassed by far. Moreover, the latency is small and the TCP/IP protocol can be used in its unchanged form.
87

Swim: A New Multicast Routing Algorithm For Wireless Networks

Akyurek, Alper Sinan 01 July 2011 (has links) (PDF)
In this work, a new multicast routing algorithm for wireless networks is presented. The algorithm, called SWIM (Source-initiated WIreless Multicast), is a depth-optimal multicast tree formation algorithm. SWIM is fully distributed and has an average computational complexity of O(N 2 ). SWIM forms a shared tree from the source(s) to destinations / yet, as a by-product, it creates a multicast mesh structure by maintaining alternative paths at every tree node. This makes SWIM suitable for both ad hoc networks and access networks with multiple gateways. An extension to the main algorithm is presented for the use in dynamic networks with mobility and/or dynamic destination group. Performance of SWIM is studied with simulations and is compared to other algorithms in the literature. Due to depth optimality, SWIM achieves a lower average and maximum delay than the compared algorithms. The throughput performance is found to be high. Working capability with rateless codes are also studied.
88

Routage des données dans les réseaux centrés sur les contenus / Routing Named Data in Information-Centric Networks

Kerrouche, Abdelali 26 May 2017 (has links)
Les Réseaux Orientés Contenus (Information Centric Networking (ICN)) représentent un nouveau paradigme qui se développe de plus en plus dans le monde de l’Internet. Ils mettent en avant de nouvelles approches centrées sur le contenu pour concevoir une nouvelle architecture pour le réseau Internet du futur dont l’usage bascule aujourd’hui d’une communication orientée machines (hosts) vers une distribution et une récupération de contenus à large échelle.Dans ce cadre, plusieurs architectures de type ICN ont été proposées par la communauté scientifique dans le cadre de plusieurs projets internationaux : DONA, PURSUIT, SAIL, COMET, CONVERGENCE, Named Data Networking (NDN), etc.Nos travaux de thèse se sont focalisés sur la problématique du routage dans les réseaux de ce type, au travers d’une architecture de type NDN qui représente aujourd’hui une des architectures ICN les plus évoluées.En particulier, nous nous sommes intéressés à concevoir et à mettre en œuvre des solutions de routage qui intègrent les métriques de qualité de service (QdS) dans les architectures NDN au regard de usages courants dans le réseau Internet. Celui-ci est en effet caractérisé par une hétérogénéité des liaisons et des conditions de trafic hautement dynamiques.Dans ce type d’architectures, la diffusion des paquets de données est organisée en deux plans : le plande routage et le plan d’acheminement. Ce dernier est responsable de l’acheminement des paquets sur l’ensemble des chemins disponibles au moyen d’une stratégie identifiée en amont. Le plan du routage est quant à lui utilisé uniquement pour soutenir le plan d’acheminement. De fait, les solutions que nous proposons consistent en de nouvelles stratégies d’acheminement avec QdS que nous qualifions d’adaptatives. Ces stratégies sont capables de transmettre les paquets sur de multiples chemins tout en considérant les paramètres de QdS liés à l’état du réseau et collectés en temps réel.La première approche proposée est conçue sur la base d’une méthode d’apprentissage inductif,du type Q-learning en ligne, et est utilisée pour estimer les informations collectées sur l’état dynamique du réseau.La deuxième contribution consiste dans une stratégie d’acheminement adaptatif conçue pour les architectures NDN et prenant en compte les métriques liées à la QdS. Elle est basée sur les similarités entre le processus d’acheminement des paquets dans les architectures NDN et le comportement des fourmis lors de la recherche du plus court chemin entre leur nid et les sources de nourriture. Les techniques utilisées pour concevoir cette stratégie sont inspirées des approches d’optimisation utilisées dans les algorithmes de type « colonies de fourmis ».Enfin, dans la dernière partie de la thèse, nous généralisons l’approche décrite ci-dessus pour l’étendre à la prise en compte simultanée de plusieurs paramètres de QdS. Sur la base de ces mêmes principes, cette approche a ensuite été étendue à la résolution des problèmes liés à la congestion.Les résultats obtenus montrent l’efficacité des solutions proposées dans une architecture NDN et permettent ainsi de considérer les paramètres de QdS dans les mécanismes d’acheminement des paquets ouvrant la voie à diverses applications orientées contenus sur ce type d’architecture / The Information Centric Networking (ICN) represents a new paradigm that is increasingly developed within the Internet world. It brings forward new content-centric based approaches, in order to design a new architecture for the future Internet, whose usage today shifts from a machine oriented communication (hosts) to a large-scale content distribution and retrieval.In this context, several ICN architectures have been proposed by the scientific community, within several international projects: DONA, PURSUIT, SAIL, COMET, CONVERGENCE, Named Data Networking (NDN), etc.Our thesis work has focused on the problems of routing in such networks, through a NDN architecture, which represents one of the most advanced ICN architectures nowadays.In particular, we were interested in designing and implementing routing solutions that integrate quality-of-service metrics (QoS) in the NDN architecture in terms of current Internet usage. This latter is indeed characterized by a heterogeneity of connections and highly dynamic traffic conditions.In this type of architecture, data packets broadcast is organized in two levels: the routing planand the forwarding plane. The latter is responsible for routing packets on all available paths through an identified upstream strategy. The routing plan is meanwhile used only to support the forwarding plane. In fact, our solutions consist of new QoS routing strategies which we describe as adaptive. These strategies can transmit packets over multiple paths while taking into account the QoS parameters related to the state of the network and collected in real time.The first proposed approach is designed on the basis of a on-line Q-learn type inductive learning method, and is used to estimate the information collected on the dynamic state of the network.The second contribution is an adaptive routing strategy designed for NDN architectures which considers the metrics related to QoS. It is based on the similarities between the packet forwarding process in the NDN architecture and the behavior of ants when finding the shortest path between their nest and food sources. The techniques used to design this strategy are based on optimization approaches used "ant colonies" algorithms.Finally, in the last part of the thesis, we generalize the approach described above to extend it to the simultaneous consideration of several QoS parameters. Based on these principles, this approach was later extended to solving problems related to congestion.The results show the effectiveness of the proposed solutions in an NDN architecture and thus allow to consider QoS parameters in packet delivery mechanisms paving the way for various content-oriented applications on this architecture
89

Grafický simulátor superskalárních procesorů / Graphical Simulator of Superscalar Processors

Vávra, Jan January 2021 (has links)
Práce se zabývá implementací simulátoru superskalárního procesoru. Implementace se odvíjí od existujících simulátorů a jejich chybějících částí. Simulátor umí vykonávat instrukční sadu RISC-V, ovšem je umožněno přidání jakékoli RISC instrukční sady. Simulátor má deterministickou predikci skoku. Části procesoru lze upravovat. Součástí je i editor kódu pro danou instrukční sadu.
90

Autonomous Priority Based Routing for Online Social Networks

Othman, Salem 14 June 2018 (has links)
No description available.

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