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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

Adaptive Path Planning for an Autonomous Marine Vehicle Performing Cooperative Navigation for Autonomous Underwater Vehicle

Hudson, Jonathan 09 April 2012 (has links)
Adaptive path planning of an autonomous marine vehicle (surface or subsurface) in the role of a communication and navigation aid (CNA) for multiple autonomous underwater vehicles (AUVs) for survey missions is studied. This path planning algorithm can be run before deployment, based on the planned paths of the survey AUVs, or underway, based on information transmitted by the survey AUVs. The planner considers the relative depth of the CNA and survey AUVs (not previously done) allowing the CNA to better aid survey AUVs that maintain a set distance over the ocean floor while surveying. Results are presented from simulations and in-water trials for both pre-deployment and underway planning modes, the latter being preferred since it can adapt to the survey AUV path during the mission. The necessity of bounding the distance between the CNA and any survey AUV in order to bound survey AUV position error is also described.
2

Advanced Traffic Service / Avancerad Trafiktjänst

Löfås, Peter January 2005 (has links)
<p>More and more travellers use navigation-aid software to find the way while driving. Most of todays systems use static maps with little or no information at all about currently yeilding roads conditions and disturbances in the network. It is desirable for such services</p><p>in the future to include information about road works, accidents, surface conditions and other types of events that affects what route is currently the best.</p><p>It is also desirable to notify users about changes in the prerequisites of the chosen route after they have started their trip.</p><p>This thesis investigates methods to include dynamic traffic information in route calculations and notifying users when the characteristics change for their chosen route.</p><p>The thesis utilizes dynamic traffic information from The Swedish Road Agencys (Vägverket) central database for traffic information, TRISS and calculates affected clients with help of positioning through the GSM network.</p>
3

Advanced Traffic Service / Avancerad Trafiktjänst

Löfås, Peter January 2005 (has links)
More and more travellers use navigation-aid software to find the way while driving. Most of todays systems use static maps with little or no information at all about currently yeilding roads conditions and disturbances in the network. It is desirable for such services in the future to include information about road works, accidents, surface conditions and other types of events that affects what route is currently the best. It is also desirable to notify users about changes in the prerequisites of the chosen route after they have started their trip. This thesis investigates methods to include dynamic traffic information in route calculations and notifying users when the characteristics change for their chosen route. The thesis utilizes dynamic traffic information from The Swedish Road Agencys (Vägverket) central database for traffic information, TRISS and calculates affected clients with help of positioning through the GSM network.
4

Conception d'un système de navigation sans fil à faible consommation pour les personnes malvoyantes / Designing a wireless navigation system with low consumption for the visually impaired

Nguyen, Thanh Huong 14 November 2014 (has links)
Au cours des dernières décennies, le développement rapide de la technologie sans fil et micro-électronique a provoqué un profond impact sur notre vie quotidienne. Parallèlement à la tendance, les technologies d'assistance ont été révolutionnées en termes de miniaturisation et de portabilité. Les traditionnels encombrants systèmes de dispositifs aidés, à connexion filaire sont maintenant remplacés par d'autres plus compacts, légers et portables. Le nombre de personnes aveugles et ayant une déficience visuelle continue à faire face à de nombreuses difficultés dans la vie quotidienne, en particulier dans la mobilité et la navigation. La théorie de la substitution sensorielle dans laquelle l'information obtenue d'une modalité sensorielle, peut atteindre les structures du cerveau physiologiquement par d'autres modalités sensorielles; par conséquent, il est possible pour les personnes aveugles et malvoyantes d'obtenir les informations désirées par d'autres sens. Sur la base de ces technologies et principes, nous voulons améliorer le Tongue Display Unit, un dispositif de visio-tactile lingual a été inventé par le professeur Bach-y-Rita à un, dispositif à long terme sans fil portable pour la navigation. Afin de rendre ce dispositif autonome, certaines propriétés doivent être étudiées: l'optimisation de la consommation d'énergie (à faire à long terme) et la communication sans fil efficace. Nous avons fait un examen très détaillé afin de choisir les composants optimaux et la méthode adéquate pour notre système. La conception du matériel a été effectuée en choisissant le meilleur algorithme. Le module émetteur-récepteur sans fil basé sur ZigBee contribue à réduire la consommation globale d'énergie. Notre antenne omnidirectionnelle est appropriée pour une utilisation chez les personnes aveugles qui ne peuvent pas être orientés à l'avance. Nous avons modifié tous les composants de la TDU, du matériel au logiciel, à partir du contrôleur à l'actionneur. La conception de l'ensemble d'électrodes n'est pas rectangulaire comme traditionnellement mais sous une forme ronde avec un soutien utilisé pour la direction et à la navigation. Enfin, le système a été validé par TDU fonctionnement en temps réel et testé sur les utilisateurs réels. Les performances du système en termes de design et d'énergie ont été améliorées. La communication sans fil est plus efficace et consomme moins d'énergie. Les premiers résultats sur les essais des utilisateurs montrent une assez bonne perception de notre TDU. / Over the last decades, the rapid development of wireless technology and microelectronic has caused a profound impact on our daily lives. Alongside the trend, assistive technologies have revolutionized in terms of miniaturization and wearability. The traditional bulky aided devices systems with wired connection are now replaced by the compact, lightweight and portable ones. The number of blind and visually impaired people continues to deal with many difficulties in daily lives, especially in mobility and navigation. The theory of sensory substitution in which information gained from one sensory modality can reach brain structures physiologically through other sensory modalities; therefore, it is possible for the blind and visually impaired people to get desired information via other senses. Based on these technologies and principles, we want to enhance the Tongue Display Unit, a lingual visuo-tactile device was invented by Professor Bach-y-Rita to a wireless, wearable, long-term device for navigation. In order to make such device, some properties have to be studied: optimization of energy consumption (to make it long-term) and efficient wireless communication. We made a very detailed review in order to choose the optimal components and method for our system. The hardware design was calculated and selected the best algorithm. The ZigBee-based wireless transceiver module contributes to reducing the overall power consumption. Our omnidirectional antenna is appropriate for usage in blind people who cannot orient in advance. We modified all components of the TDU, from the hardware to software, from controller to actuator. The design of the electrode array is not rectangular as traditional but in a round shape which is supportively used for direction and navigation. Lastly the TDU system was validated by real-time operation and tested on real users. The performance of the system in terms of design and energy has been improved. The wireless communication is more effective and consumes less power. The primary results on users' trials show rather good perception on our TDU.
5

Optimalizace sítě pozemních radionavigačních prostředků zabezpečení RNAV ve FIR Praha / Optimization of the ground network infrastructure of radio navigation aids for RNAV in FIR Praha

Krejčí, Jan January 2014 (has links)
This diploma thesis concerns with creating of study which deals with the optimization of the ground network infrastructure of radio navigation aids for RNAV in FIR Praha. The thesis contains an analysis of concept of development of Czech navigation environment and introduces DEMETER software, in which the optimization analyses are realized. The thesis describes DME/DME navigation system from the perspective of individual components and parameters. The actual study deals with an optimization of the ground network infrastructure of the radio navigation aids and includes the definition of network performance requirements, creation of general methodology of optimization of navigation performance analysis and a procedure of choosing a suitable placement of radio navigation aid. The integral parts of the study are analyses of current state of navigation performance and analyses of possible improvement of radio navigation infrastructure.

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