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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.
11

Pricing and Scheduling Optimization Solutions in the Smart Grid

Zhao, Binyan 09 September 2015 (has links)
The future smart grid is envisioned as a large scale cyber-physical system encompassing advanced power, computing, communications and control technologies. This work provides comprehensive accounts of the application with optimization methods, probability theory, commitment and dispatching technologies for addressing open problems in three emerging areas that pertain to the smart grid: unit commitment, service restoration problems in microgrid systems, and charging services for the plug-in hybrid electric vehicle (PHEV) markets. The work on the short-term scheduling problem in renewable-powered islanded microgrids is to determine the least-cost unit commitment (UC) and the associated dispatch, while meeting electricity load, environmental and system operating requirements. A novel probability-based concept, {\em probability of self-sufficiency}, is introduced to indicate the probability that the microgrid is capable of meeting local demand in a self-sufficient manner. Furthermore, we make the first attempt in approaching the mixed-integer UC problem from a convex optimization perspective, which leads to an analytical closed-form characterization of the optimal commitment and dispatch solutions. The extended research of the renewable-powered microgrid in the connection mode is the second part of this work. In this situation, the role of microgrid is changed to be either an electricity provider selling energy to the main grid or a consumer purchasing energy from the main grid. This interaction with the main grid completes work on the scheduling schemes. Third, a microgrid should be connected with the main grid most of the time. However, when a blackout of the main grid occurs, how to guarantee reliability in a microgrid as much as possible becomes an immediate question, which motivates us to investigate the service restoration in a microgrid, driven islanded by an unscheduled breakdown from the main grid. The objective is to determine the maximum of the expected restorative loads by choosing the best arrangement of the power network configurations immediately from the beginning of the breakdown all the way to the end of the island mode. Lastly, the work investigating the pricing strategy in future PHEV markets considers a monopoly market with two typical service classes. The unique characteristics of battery charging result in a piecewise linear quality of service model. Resorting to the concept of subdifferential, some theoretical results, including the existence and uniqueness of the subscriber equilibrium as well as the convergence of the corresponding subscriber dynamics are established. In the course of developing revenue-maximizing pricing strategies for both service classes, a general tradeoff has been identi ed between monetization and customer acquisition. / Graduate
12

Pile de protocoles pour des réseaux des capteurs avec récupération d'énergie / Energy Efficient Protocols for Harvested Wireless Sensor Networks

Romaniello, Gabriele 17 March 2015 (has links)
Cette thèse vise à améliorer la pile de protocoles pour réseaux de capteurs sans fil à récupération d'énergie afin de les rendre autonomes dans un contexte multi-saut. Elle s'inscrit dans le projet GreenNet de STMicroelectronics qui a pour objectif de concevoir et développer une nouvelle génération d'objets intelligent basés sur la récupération d'énergie ambiente en vue de l'intégration dans l'Internet des Objets. L'originalité de la plateforme GreenNet repose sur sa petite taille qui implique une faible capacité de stockage d'énergie ainsi qu'une faible capacité de récupération d'énergie. Avec un si faible budget d'énergie, les protocoles standards ou les solutions proposées par les communautés académique/industrielle ne permettant pas d'assurer un fonctionnement autonome de ces réseaux. Dans cette thèse, nous analysons les protocoles standards et les solutions existantes pour identifier leurs limites avec la plateforme GreenNet. Ensuite, nous proposons 3 contributions afin de permettre cette autonomie. La première contribution est MCBT, un protocole permettant d'accélérer la découverte et le rattachement de nouveaux noeuds à un réseau multi saut et multi-canaux en formation ou existent. Ce protocole réduit efficacement l'énergie dépensée dans cette phase fortement consommatrice. La deuxième contribution est STADA, un algorithme adaptant l'activité des capteurs en fonction des conditions locales de trafic et d'énergie disponible. STADA est basé sur une fonction de pondération qui tient compte de l'énergie présente dans la batterie, du taux de récupération d'énergie et du trafic local. Enfin, notre troisième contribution propose une nouvelle métrique de routage basée sur Expected Delay synthétisant en une seule variable monotone des facteurs tels que l'éloignement au puits, les chemins bénéficiant d'un ordonnancement de relayage de paquet privilégié et de périodes cumulées d'activité des radios sur le chemin favorable. Toutes les solutions proposées sont conçues pour fonctionner avec la norme IEEE 802.15.4 slotté et sont facilement transposables à son évolution définie par la norme IEEE 802.15.4e. Nous avons validé les protocoles proposés grâce à un simulateur émulant des noeuds réels (Cooja) et au simulateur WSNet. Les résultats ont montré de meilleures performances en termes de consommation d'énergie et de qualité de service par rapport à l'existant. / This thesis concerns energy efficient protocols for harvested wireless sensor networks. It is a part of an industrial Internet of Things project. STMicroelectronics started the GreenNet project with the objective to develop and design a new generation of harvesting smart objects to be integrated in the Internet of Things. The GreenNet platform is novel with respect to the existing solutions due to its small size that implies a small energy buffer and small harvesting capabilities. This aspect makes the standard protocols and precedent solutions not directly applicable on this extremely low power platform. In this dissertation, we analyse standard protocols and existing solutions to identify their issues in the gn platform. Then, we provide protocol and algorithm adaptations to make feasible the concept of auto configurable and sustainable networks of GreenNet nodes. We proposed MCBT, an energy efficient protocol for the bootstrap procedure. It enables low power nodes to be enrolled in mh mc wireless sensor networks thanks to the network support for enrolling new nodes. It represents an energy efficient solution that extends the standard protocol. We proposed STADA, a sustainable algorithm to adapt the node activity according to the available energy and traffic conditions. STADA is based on a weighted function that takes into account the energy present in the battery, the energy harvesting rate, and network traffic. In this way, the algorithm takes into account all main parameters to adapt the energy consumption and improve the node performance. To make the harvested network more efficient according to light variations, we proposed a novel metric that makes the path choice a simple process. With the Expected Delay, we synthesize all network parameters in a single monotonic variable that facilitates the path choice in mh harvesting wireless sensor networks. All proposed solutions are designed to work with standard beacon-enabled IEEE 802.15.4 protocols and are easily portable on the future version of IEEE 802.15.4e. We validated the proposed protocols with emulations and simulations. The evaluation results shown better performance in terms of energy consumption and quality of service.
13

Multiplatformní aplikace pro správu síťových prvků Mikrotik / Multiplatform application for Mikrotik network devices management

Bárdossy, Adrián January 2018 (has links)
Diploma thesis contains the description of the application developement for management of network entities based on mikrotik devices. In the intro, there is the description of used libraries, also description of API. In the next part of thesis there is programmed part of application backend. This part contains description of individual directories of project, which was written in pycharm. Every directory is described by one file together with UML diagram and table of methods in specific class. In the next part of thesis, there is the description of graphical part of the application and its example on one section of programmed buttons. It contains also output in form of pictures from the application. In the last section, there is tutorial for modules instalation, which are needed to run the application and contains manual testing of application.
14

Analýza síťové bezpečnosti / Network-wide Security Analysis

de Silva, Hidda Marakkala Gayan Ruchika Unknown Date (has links)
Práce představuje model a metody analýzy vlasností komunikace v počítačových sítích. Model dosažitelnosti koncových prvků v IP sítích je vytvořen na základě konfigurace a síťové topologie a umožňuje ukázat, že vabraný koncový uzel je dosažitelný v dané síťové konfiguraci a stavu.   Prezentovaná práce se skládá ze dvou částí. První část se věnuje modelování sítí, chování směrovaích protokolů a síťové konfiguraci. V rámci modelu sítě byla vytvořena modifikovaná topologická tabulka (MTT), která slouží pro agregaci síťových stavů určených pro následnou analýzu. Pro analýzu byl použit přístup založený na logickém programování, kdy model sítě je převeden do Datalog popisu a vlastnosti jsou ověřovány kladením dotazů nad logickou databází. Přínosy práce spočívají v definici grafu síťových filtrů, modifikované topologické tabulce, redukce stavového prostoru agrgací síťových stavů, modelů aktivního síťového prvku jako filter-transformace komponenty a metoda pro analýzu dosažitelnosti založena na logickém programování a databázích.
15

Automating End Station Configuration: An Agile Approach to Time-Sensitive Networking / Automatisering av Konfiguration för Ändstationer: Ett Agilt Tillvägagångssätt för Tidskänsliga Nätverk

Hallström, Fredrik January 2023 (has links)
Industries such as automotive and industrial automation are pushing the limits of networking technology. The Time-Sensitive Networking (TSN) standards offer a promising solution that can meet the demands of high-bandwidth applications with strict timing constraints, allowing time-critical traffic to coexist with other traffic. However, TSN is relatively new, with much research necessary before it is usable in the industry. This thesis addresses the problem of the common manual configuration of end stations, being time-consuming and error-prone. Through exploring the TSN standards, this thesis attempts to solve the configuration problem by providing a proof-of-concept for both design and implementation of a software architecture managing the end stations and automating their configuration process. Adopting an agile and iterative approach made the complexity of TSN manageable. Furthermore, this thesis has been guided by the research question: How can the configuration of a TSN end station be automated? The design was split into three components: an interface, a configuration manager, and a TSN library. In addition, a communication protocol between the end stations and the Centralized Network Configuration (CNC) is established. The implementation of the proposed design used Python for all three modules in the end station management software, with the REST protocol for the interface. After presenting the implementation, it was evaluated to show the performance of the implemented end station management software. The results showed that the management software would likely not be the bottleneck, as other components it depends on are considerably slower. This thesis and its research contribution offer a practical foundation for continued research and development, such as investigating the configuration of the end stations, providing proofs-of-concept for engineering tools with specific use cases, and finalizing a TSN system. / Industrier som fordons- och industriautomation tänjer på gränserna av nätverksteknik. Time-Sensitive Networking (TSN) standarderna är en lovande lösning som lovar att möta kraven för applikationer med krav på hög bandbredd och strikta tidskrav, som samtidigt tillåter tidskritisk trafik att existera tillsammans med annan trafik. Dock är TSN relativt nytt och i stort behov av mer forskning innan det kan användas i industrin. Den här avhandlingen adresserar problemet med manuell konfiguration av ändstationer, som är både tidskrävande och felbenäget. Genom att utforksa TSN standarderna försöker den här avhandlingen lösa konfigurationsproblemet genom att ta fram ett koncept för design och implementation av en mjukvaruarkitektur för att hantera ändstationer och automatisera deras konfigurationsprocess. Genom att anta en agil och iterativ metod blev komplexiteten hos TSN hanterbar. Dessutom har den här avhandlingen styrts av forskningsfrågan: Hur kan konfigurationen av TSN ändstationer automatiseras? Designen delades upp i tre komponenter: ett gränssnitt, en konfigurationshanterare, samt ett TSN-bibliotek. Utöver detta etablerades ett kommunikationsprotokoll mellan ändstationer och en Centralized Network Configuration (CNC). Implementationen av den föreslagna designen använde sig av Python för de tre komponenterna, med REST-protokollet för gränssnittet. Efter presentationen av implementationen utvärderades den för att visa prestandan hos den implementerade mjukvaran för ändstationen. Resultaten visade att mjukvaran sannolikt inte skulle vara en flaskhals, då andra komponenter som den är beroende av, är betydligt långsammare. Den här avhandligen och dess forskningsbidrag erbjuder en praktiskt grund för fortsatt forskning och utveckling, som undersökning av konfigurationen för ändstationer, framtagning av koncept för ingenjörsverktyg med specifika användningsfall, samt att slutföra ett TSN-system.
16

Supply network configuration for small series, high-cost production : Exploring the European textile and apparel industry context

Harper, Sara January 2020 (has links)
The purpose of this thesis is to increase the understanding of supply network configuration (SNC) for small series production in high-cost contexts in relation to the textile/apparel industry. SNC encompasses strategic structural and infrastructural decisions at the supply chain level, motivated by capabilities/priorities. The key configuration decisions addressed concern textile/apparel production in Europe, with associated context-specific advantages and challenges. The thesis takes a particular focus on how practitioners consider these configurations and motivations. The thesis begins with identification of motivations for locating textile/apparel production in high-cost contexts, to capture the driving priorities. Thereafter, the thesis extends the focus beyond location motivations to identify the key SNC aspects and characteristics for small series production in high-cost contexts. These configuration-related aspects and capabilities are elaborated upon and modelled to understand how they are interrelated in textile/apparel industry contexts. The empirical work uses mixed-methods and seeks to bring together the relevant topics using a SNC and capabilities approach. The specific methods, Delphi study and interpretive structural modeling, are focused on sensitivity practitioner perspectives. Findings show multiple key motivations/capabilities for high-cost textile/apparel production, specifically small series production (customization); which is closely linked with several other priorities, including quality and flexibility/delivery. Expanding the view to the SNC aspects, the findings confirm and extend the literature regarding complexities, multi-level characteristics, synergies and trade-offs, and industry/location contingencies. Regarding this European textile/apparel context, several interrelated considerations create challenges with respect to balancing configuration, capabilities and location; in particular related to multiple priorities such as flexibility/delivery, quality, innovation/sustainability, and the level of product variety/customization. Several relational characteristics are also crucial, including focus on trust and information sharing, although, with a few significant exceptions, limited supplier integration levels are found. These findings indicate the need to build upon existing relationships to develop end-to-end digital connections. The thesis approaches issues at the intersection of theory and practice, regarding configuring supply networks for small series production in high-cost contexts. Practically, it develops an approach to evaluate and model decision aspects, demonstrating how this can be used with a variety of textile/apparel companies. Several extensions are required to support current and future state mapping, including developments related to the method and the addition of performance considerations. The thesis contributes to theory by broadening the focus on high-cost locations to include small series production and the SNC perspective. Thus, the research confirms multiple priorities including innovation and sustainability; additionally finding several challenges associated with small series textile/apparel production in high-cost contexts. Further research should extend the focus to understand (re)configuration processes, and implications on priorities like sustainable innovation.
17

Ontology mapping: a logic-based approach with applications in selected domains

Wong, Alfred Ka Yiu, Computer Science & Engineering, Faculty of Engineering, UNSW January 2008 (has links)
In advent of the Semantic Web and recent standardization efforts, Ontology has quickly become a popular and core semantic technology. Ontology is seen as a solution provider to knowledge based systems. It facilitates tasks such as knowledge sharing, reuse and intelligent processing by computer agents. A key problem addressed by Ontology is the semantic interoperability problem. Interoperability in general is a common problem in different domain applications and semantic interoperability is the hardest and an ongoing research problem. It is required for systems to exchange knowledge and having the meaning of the knowledge accurately and automatically interpreted by the receiving systems. The innovation is to allow knowledge to be consumed and used accurately in a way that is not foreseen by the original creator. While Ontology promotes semantic interoperability across systems by unifying their knowledge bases through consensual understanding, common engineering and processing practices, it does not solve the semantic interoperability problem at the global level. As individuals are increasingly empowered with tools, ontologies will eventually be created more easily and rapidly at a near individual scale. Global semantic interoperability between heterogeneous ontologies created by small groups of individuals will then be required. Ontology mapping is a mechanism for providing semantic bridges between ontologies. While ontology mapping promotes semantic interoperability across ontologies, it is seen as the solution provider to the global semantic interoperability problem. However, there is no single ontology mapping solution that caters for all problem scenarios. Different applications would require different mapping techniques. In this thesis, we analyze the relations between ontology, semantic interoperability and ontology mapping, and promote an ontology-based semantic interoperability solution. We propose a novel ontology mapping approach namely, OntoMogic. It is based on first order logic and model theory. OntoMogic supports approximate mapping and produces structures (approximate entity correspondence) that represent alignment results between concepts. OntoMogic has been implemented as a coherent system and is applied in different application scenarios. We present case studies in the network configuration, security intrusion detection and IT governance & compliance management domain. The full process of ontology engineering to mapping has been demonstrated to promote ontology-based semantic interoperability.
18

On Optimization in Design of Telecommunications Networks with Multicast and Unicast Traffic

Prytz, Mikael January 2002 (has links)
No description available.
19

On Optimization in Design of Telecommunications Networks with Multicast and Unicast Traffic

Prytz, Mikael January 2002 (has links)
No description available.
20

Ontology mapping: a logic-based approach with applications in selected domains

Wong, Alfred Ka Yiu, Computer Science & Engineering, Faculty of Engineering, UNSW January 2008 (has links)
In advent of the Semantic Web and recent standardization efforts, Ontology has quickly become a popular and core semantic technology. Ontology is seen as a solution provider to knowledge based systems. It facilitates tasks such as knowledge sharing, reuse and intelligent processing by computer agents. A key problem addressed by Ontology is the semantic interoperability problem. Interoperability in general is a common problem in different domain applications and semantic interoperability is the hardest and an ongoing research problem. It is required for systems to exchange knowledge and having the meaning of the knowledge accurately and automatically interpreted by the receiving systems. The innovation is to allow knowledge to be consumed and used accurately in a way that is not foreseen by the original creator. While Ontology promotes semantic interoperability across systems by unifying their knowledge bases through consensual understanding, common engineering and processing practices, it does not solve the semantic interoperability problem at the global level. As individuals are increasingly empowered with tools, ontologies will eventually be created more easily and rapidly at a near individual scale. Global semantic interoperability between heterogeneous ontologies created by small groups of individuals will then be required. Ontology mapping is a mechanism for providing semantic bridges between ontologies. While ontology mapping promotes semantic interoperability across ontologies, it is seen as the solution provider to the global semantic interoperability problem. However, there is no single ontology mapping solution that caters for all problem scenarios. Different applications would require different mapping techniques. In this thesis, we analyze the relations between ontology, semantic interoperability and ontology mapping, and promote an ontology-based semantic interoperability solution. We propose a novel ontology mapping approach namely, OntoMogic. It is based on first order logic and model theory. OntoMogic supports approximate mapping and produces structures (approximate entity correspondence) that represent alignment results between concepts. OntoMogic has been implemented as a coherent system and is applied in different application scenarios. We present case studies in the network configuration, security intrusion detection and IT governance & compliance management domain. The full process of ontology engineering to mapping has been demonstrated to promote ontology-based semantic interoperability.

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