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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.
101

Adaptive, reliable, and accurate positioning model for location-based services

al Nabhan, Mohammad Mousa January 2009 (has links)
This thesis presents a new strategy in achieving highly reliable and accurate position solutions fulfilling the requirements of Location-Based Services (LBS) pedestrians’ applications. The new strategy is divided into two main parts. The first part integrates the available positioning technology within the surrounding LBS application context by introducing an adaptive LBS framework. The context can be described as a group of factors affecting the application behaviour; this includes environmental states, available resources and user preferences. The proposed adaptive framework consists of several stages, such as defining the contextual factors that have a direct effect on the positioning performance, identifying preliminary positioning performance requirements associated with different LBS application groups, and introducing an intelligent positioning services selection function. The second part of this work involves the design and development of a novel positioning model that is responsible for delivering highly reliable, accurate and precise position solutions to LBS users. This new model is based on the single frequency GPS Standard Positioning Service (SPS). Additionally, it is incorporated within the adaptive LBS framework while providing the position solutions, in which all identified contextual factors and application requirements are accounted. The positioning model operates over a client-server architecture including two main components, described as the Localisation Server (LS) and the Mobile Unit (MU). Hybrid functional approaches were developed at both components consisting of several processing procedures allowing the positioning model to operate in two position determination modes. Stand-alone mode is used if enough navigation information was available at the MU using its local positioning device (GPS/EGNOS receiver). Otherwise, server-based mode is utilised, in which the LS intervenes and starts providing the required position solutions. At the LS, multiple sources of GPS augmentation services were received using the Internet as the sole augmentation data transportation medium. The augmentation data was then processed and integrated for the purpose of guaranteeing the availability of valid and reliable information required for the provision of accurate and precise position solutions. Two main advanced position computation methods were developed at the LS, described as coordinate domain and raw domain. The positioning model was experimentally evaluated. According to the reported results, the LS through the developed position computation methods, was able to provide position samples with an accuracy of less than 2 meters, with high precision at 95% confidence level; this was achieved in urban, rural, and open space (clear satellite view) navigation environments. Additionally, the integrity of the position solutions was guaranteed in such environments during more than 90% of the navigation time, taking into consideration the identified integrity thresholds (Horizontal Alert Limits (HAL)=11 m). This positioning performance has outperformed the existing GPS/EGNOS service which was implemented at the MU in all scenarios and environments. In addition, utilising a simulation evaluation facility the developed positioning model performance was quantified with reference to a hybrid positioning service that will be offered by future Galileo Open Service (OS) along with GPS/EGNOS. Using the statistical t-test, it was concluded that there is no significant difference in terms of the position samples’ accuracy achieved from the developed positioning model and the hybrid system at a particular navigation environment described as rural area. The p-value was 0.08 and the level of significance used was 0.05. However, a significant difference in terms of the service integrity for the advantage of the hybrid system was experienced in all remaining scenarios and environments more especially the urban areas due to surrounding obstacles and conditions.
102

Multi-dimensional-personalization in mobile contexts

Schilke, Steffen Walter January 2013 (has links)
During the dot com era the word 'personalisation' was a hot buzzword. With the fall of the dot com companies the topic has lost momentum. As the killer application for UMTS or the mobile internet has yet to be identified, the concept of Multi-Dimensional-Personalisation (MDP) could be a candidate. Using this approach, a recommendation of mobile advertisement or marketing (i.e., recommendations or notifications), online content, as well as offline events, can be offered to the user based on their known interests and current location. Instead of having to request or pull this information, the new service concept would proactively provide the information and services – with the consequence that the right information or service could therefore be offered at the right place, at the right time. The growing availability of "Location-based Services“ for mobile phones is a new target for the use of personalisation. "Location-based Services“ are information, for example, about restaurants, hotels or shopping malls with offers which are in close range/short distance to the user. The lack of acceptance for such services in the past is based on the fact that early implementations required the user to pull the information from the service provider. A more promising approach is to actively push information to the user. This information must be from interest to the user and has to reach the user at the right time and at the right place. This raises new requirements on personalisation which will go far beyond present requirements. It will reach out from personalisation based only on the interest of the user. Besides the interest, the enhanced personalisation has to cover the location and movement patterns, the usage and the past, present and future schedule of the user. This new personalisation paradigm has to protect the user's privacy so that an approach supporting anonymous recommendations through an extended 'Chinese Wall' will be described.
103

Investigation of Mach-Zehnder modulators in the context of fibre supported mm-wave communications

Jones, Warren Richard January 1995 (has links)
No description available.
104

Services à haute intensité technologique : l'adoption des services de données pour téléphonie mobile en France / Technology-based services : data mobile services adoption in France

Moreno Alcerreca, Christina 22 March 2010 (has links)
Face au développement des services à haute intensité technologique, se pose le problème de leur acceptation. En téléphonie mobile, les Français se rallient progressivement à ces services et cette thèse vise à comprendre cette adoption. La revue de littérature fondée sur l’adoption des innovations et son adaptation au domaine des services permet d’identifier les principaux facteurs qui influencent l’adoption des services à haute intensité technologique. Une étude qualitative exploratoire a permis d’enrichir notre cadre conceptuel que nous avons testé dans une seconde phase auprès de 350 utilisateurs de services mobiles. Finalement, la réalisation d’une étude de cas s’est avérée nécessaire pour expliquer le décollage des services de données en France à partir du lancement sur le marché d’un nouveau téléphone multifonction Smartphone en 2007-2008. Les résultats des trois études réalisées révèlent que les principaux construits du TAM sont pertinents pour expliquer l’utilisation des services à haute intensité technologique. Nos résultats mettent en valeur l’influence des communautés de marque dans le processus d’adoption des équipements et services mobiles. / With the development of technology-based services the question of the level of their acceptance was raised. In mobile communication, the French progressively adopt these services. This thesis aims to understand this adoption. The study of the literature in innovations adoption helped us to identify the main factors influencing technology-based services adoption. An exploratory quality study helped us to enrich our conceptual framework. The proposed model was evaluated by quantitative survey among 350 mobile services users. Finally, the execution of a case study proved itself necessary to explain the take-off of the mobile data services in France due to the launch of a multifunction Smartphone device. The results of the three studies reveal that the TAM constructions are pertinent in the explanation of the technology-based services usage. Our results highlight the influence of brand communities in the technology-based services adoption process.
105

Ddos Defense Against Botnets in the Mobile Cloud

Jensen, David 05 1900 (has links)
Mobile phone advancements and ubiquitous internet connectivity are resulting in ever expanding possibilities in the application of smart phones. Users of mobile phones are now capable of hosting server applications from their personal devices. Whether providing services individually or in an ad hoc network setting the devices are currently not configured for defending against distributed denial of service (DDoS) attacks. These attacks, often launched from a botnet, have existed in the space of personal computing for decades but recently have begun showing up on mobile devices. Research is done first into the required steps to develop a potential botnet on the Android platform. This includes testing for the amount of malicious traffic an Android phone would be capable of generating for a DDoS attack. On the other end of the spectrum is the need of mobile devices running networked applications to develop security against DDoS attacks. For this mobile, phones are setup, with web servers running Apache to simulate users running internet connected applications for either local ad hoc networks or serving to the internet. Testing is done for the viability of using commonly available modules developed for Apache and intended for servers as well as finding baseline capabilities of mobiles to handle higher traffic volumes. Given the unique challenge of the limited resources a mobile phone can dedicate to Apache when compared to a dedicated hosting server a new method was needed. A proposed defense algorithm is developed for mitigating DDoS attacks against the mobile server that takes into account the limited resources available on the mobile device. The algorithm is tested against TCP socket flooding for effectiveness and shown to perform better than the common Apache module installations on a mobile device.
106

Regulating mobile money to create an enabling business environment

Kausch, Bronwen Ashley 07 June 2013 (has links)
The technology to deliver mobile money services has been in place for over a decade, yet very few mobile money operations have reached scale. The purpose of the following research is to explore the possible reasons for this by analysing factors which impact the rollout and uptake of services. This is achieved through a case study of mobile money service offerings in the developing world in general and South Africa in particular. Findings of the research highlight the complexities of the challenge of reaching scale, particularly those relating to regulations, finding the appropriate business models and other socio-political factors. A further finding points to a possible lack of appropriate skills in the mobile money industry as a reason for services not reaching scale.
107

A review of the policy and regulatory environment of mobile banking in Zimbabwe

Tahwa, Felistas Sophie. 04 March 2014 (has links)
Thesis (M.M. (ICT Policy and Regulation))--University of the Witwatersrand, Faculty of Commerce, Law and Management, Graduate School of Public and Development Management, 2013. / The dynamics in technology have ushered in innovative products such as mobile banking. It has been taken up by other economies such as Kenya, Philippines and others, each coming up with different results. The purpose of this qualitative research is to analyse and evaluate the impact of policy and regulation on the propagation of mobile banking generally but particularly in the Zimbabwe context. Findings of the research reveal a lack of articulate policy and regulation on m-banking, which has posed a challenge to the propagation of m-banking. While m-banking spans multiple domains, the research found that the respective stakeholders are currently working in isolation hence there is a need to work on co-jurisdiction. The outcome of the research shows there is currently no synergy in the awareness campaign drive and stakeholders are not willing to champion the drive. Other factors believed to contribute to the proliferation of m-banking have been identified as the restoration of customer confidence in the banking sector, a reduction of the cost of banking, a culture shift from a cash-centric economy to a non-cash culture and the addressing of intermittent electricity supply among others. The research also takes into consideration socio-economic factors that aid or hinder the rollout and effective uptake of the mobile banking service.
108

A path planning algorithm for the mobile robot in the indoor and dynamic environment based on the optimized RRT algorithm

Yan, Yu Pei January 2018 (has links)
University of Macau / Faculty of Science and Technology. / Department of Electromechanical Engineering
109

Etude d’un système de fabrication agile mobile pour composants de grande taille / Agile mobile manufacturing system for large work-pieces

Yang, Hai 10 May 2012 (has links)
Les robots industriels, bien connus pour être des systèmes de fabrication flexibles et agiles, atteignent leurs limites lorsqu'il s'agit d'effectuer des tâches sur des pièces de grande taille (par exemple: les pièces longues et minces de l'industrie aéronautique). Pour ce type des tâches, les solutions existantes sont à leurs limites: les bras manipulateurs à base fixe souffrent d'un espace de travail trop limité; les bras manipulateurs montés sur véhicule ne sont pas assez précis; les machines-outils conventionnelles doivent être conçus à méga-échelle (plusieurs dizaines de mètres). Dans la cadre de cette thèse de doctorat, nous avons proposé des solutions robotiques innovantes qui combinent la capacité de marcher (ou de grimper) sur la pièce (ou sur le montage d'usinage) avec la capacité d'usiner. De l'analyse de la topologie et de la mobilité à la modélisation géométrique et cinématique, ainsi que la proposition d'algorithmes de contrôle innovants, des robots ont été proposés et étudiés pour la réalisation des tâches d'usinage ainsi que des tâches de locomotion. Un prototype a été construit qui témoigne de la pertinence de ce concept innovant. Il repose sur une architecture parallèle à actionnement redondant (8 moteurs pour 6 degrés de liberté) et combine moteurs, freins, dispositifs de bridage et de nombreux capteurs de position. Le prototype peut se fixer sur le montage d'usinage, réaliser ses tâches de fabrication, puis modifier sa configuration pour devenir un robot marcheur capable d'atteindre la zone de travail suivante. / Industrial robots, well known as flexible and agile manufacturing systems, reach their limits when dealing with very large workpieces (e.g.: very long and slender parts found in aeronautics industry). For such tasks, existing solutions are at their limits: stationary manipulator arms suffer from a too limited workspace; manipulators mounted on a vehicle are not accurate enough; classical machine-tools must be designed at mega-scale (several tens of meters). This thesis work aims at offering an innovative robotic solution that combines the ability to walk (or climb) on the workpiece (or on the tooling that supports the workpieces) together with manufacturing ability. From the topology and mobility analysis to the geometrics and kinematics modeling, as well as innovative control algorithms proposition, the proposed mobile manufacturing robots have been studied for achieving both machining and locomotion tasks. A prototype has been built to show the concept effectiveness . It is based on a parallel mechanism with actuation redundancy (8 motors for 6 degrees-of-freedom), combining motors, brakes, clamping devices and numerous position sensors. The robot can clamp itself on the manufacturing tooling, and then change its configuration to become a walking robot able to reach the next working area.
110

Self location of vision guided autonomous mobile robots.

January 2000 (has links)
Lau Ah Wai, Calvin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 108-111). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- An Overview --- p.4 / Chapter 1.1.1 --- Robot Self Location --- p.4 / Chapter 1.1.2 --- Robot Navigation --- p.10 / Chapter 1.2 --- Scope of Thesis --- p.12 / Chapter 2 --- Theory --- p.13 / Chapter 2.1 --- Coordinate Systems Transformations --- p.13 / Chapter 2.2 --- Problem Specification --- p.21 / Chapter 2.3 --- The Process of Stereo Vision --- p.22 / Chapter 2.3.1 --- Disparity and Depth --- p.22 / Chapter 2.3.2 --- Vertical Edge Detection and Extraction --- p.25 / Chapter 2.3.3 --- Line Matching Using Dynamic Programming --- p.27 / Chapter 3 --- Mobile Robot Self Location --- p.29 / Chapter 3.1 --- Physical Points by Stereo Reconstruction --- p.29 / Chapter 3.1.1 --- Physical Points Refinement --- p.32 / Chapter 3.2 --- Motion Uncertainties Modeling --- p.33 / Chapter 3.3 --- Improved Physical Point Estimations by EKF --- p.36 / Chapter 3.4 --- Matching Physical Points to Model by Geometric Hashing --- p.40 / Chapter 3.4.1 --- Similarity Invariant --- p.44 / Chapter 3.5 --- Initial Pose Estimation --- p.47 / Chapter 3.5.1 --- Initial Pose Refinement --- p.50 / Chapter 3.6 --- Self Location Using Other Camera Combinations --- p.50 / Chapter 4 --- Improvements to Self Location Using Bayesian Inference --- p.55 / Chapter 4.1 --- Statistical Characteristics of Edges --- p.57 / Chapter 4.2 --- Evidence at One Pixel --- p.60 / Chapter 4.3 --- Evidence Over All Pixels --- p.62 / Chapter 4.4 --- A Simplification Of Geometric Hashing --- p.62 / Chapter 4.4.1 --- Simplification of The Similarity Invariant --- p.63 / Chapter 4.4.2 --- Translation Invariant --- p.63 / Chapter 4.4.3 --- Simplification to The Hashing Table --- p.65 / Chapter 5 --- Robot Navigation --- p.67 / Chapter 5.1 --- Propagation of Motion Uncertainties to Estimated Pose --- p.68 / Chapter 5.2 --- Expectation Map Derived from the CAD Model --- p.70 / Chapter 6 --- Experimental Results --- p.74 / Chapter 6.1 --- Results Using Simulated Environment --- p.74 / Chapter 6.1.1 --- Results and Error Analysis --- p.75 / Chapter 6.2 --- Results Using Real Environment --- p.85 / Chapter 6.2.1 --- Camera Calibration Using Tsai's Algorithm --- p.85 / Chapter 6.2.2 --- Pose Estimation By Geometric Hashing --- p.88 / Chapter 6.2.3 --- Pose Estimation by Bayesian Inference and Geometric Hash- ing --- p.90 / Chapter 6.2.4 --- Comparison of Self Location Approaches --- p.92 / Chapter 6.2.5 --- Motion Tracking --- p.93 / Chapter 7 --- Conclusion and Discussion --- p.95 / Chapter 7.1 --- Conclusion and Discussion --- p.95 / Chapter 7.2 --- Contributions --- p.97 / Chapter 7.3 --- Subjects for Future Research --- p.98 / Chapter A --- Appendix --- p.100 / Chapter A.1 --- Extended Kalman Filter --- p.100 / Chapter A.2 --- Visualizing Uncertainty for 2D Points --- p.105

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