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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

Contribution aux communications intra-véhicule et inter-véhicules / Contribution to Intra-Vehicular and Inter-Vehicular Communications

Ayaida, Marwane 10 December 2012 (has links)
Les véhicules modernes sont équipés de périphériques permettant d'automatiser des tâches (changement de vitesse de transmission, régulation de vitesse, etc.) ou de fournir des services à l'utilisateur (aide à la conduite, détection d'obstacles, etc.). Les communications entre les véhicules permettent d'élargir ces services grâce à la collaboration de plusieurs véhicules (prévention des accidents, gestion du trafic routier, etc.). La multiplication de ces périphériques, de leurs interfaces et protocoles rend l'échange de données plus complexe. Par ailleurs, la communication inter- véhicules est plus contraignante à cause de la haute mobilité des véhicules. Dans cette thèse, nous proposons la conception d'un canal de communication Connect to All (C2A) qui permet d'assurer l'interopérabilité entre les périphériques embarqués dans un véhicule. En effet, il détecte la connexion à chaud d'un équipement, le reconnaît et lui permet d'échanger des données avec les autres périphériques connectés. La conception du canal commence par la modélisation de ce canal en utilisant deux techniques différentes (l'outil de modélisation et de vérification UPPAAL et le Langage de Description et de Spécification (LDS)). La vérification des modèles proposés a pour but de valider le fonctionnement. Ensuite, nous détaillons une implémentation réelle du canal sur une carte embarquée qui vise à démontrer la faisabilité du concept d'interopérabilité de C2A.Nous avons aussi étudié les effets de la mobilité dans la communication inter-véhiculaires grâce à une approche hybride mixant le routage et un service de localisation. Cette approche offre un mécanisme qui permet de réduire les coûts de la localisation des véhicules tout en augmentant les performances de routage. En plus, nous comparons deux applications de cette approche : Hybrid Routing and Grid Location Service (HRGLS) et Hybrid Routing and Hierarchical Location Service (HRHLS) avec des approches originelles pour démontrer la valeur ajoutée. Cette approche est enrichie avec un algorithme de prédiction de mobilité. Ce dernier permet de mieux cerner le déplacement des véhicules en les estimant. De même, l'approche hybride avec prédiction de mobilité Predictive Hybrid Routing and Hierarchical Location Service (PHRHLS) est comparée à HRHLS et l'approche originelle afin de révéler les bénéfices de la prédiction de mobilité. / Modern vehicles are equipped with various devices that aim to automate tasks (shift transmission, cruise control, etc.) or to provide services to the user (driver assistance, obstacle detection, etc.). Communications between vehicles help to expand these services through the collaboration of several vehicles (accident prevention, traffic management, etc.). The proliferation of these devices, their interfaces and protocols makes the data exchange more complex. In addition, inter-vehicle communication is more restrictive because of the vehicles' high mobility.In this work, we propose the design of a communication channel Connect to All (C2A) that ensures the interoperability between embedded devices in a vehicle. In fact, it detects the equipment connection, recognizes it and allows it to exchange data with other devices. The channel design starts by the modelling step using two different techniques (the model checker tool UPPAAL and the Specification and Description Language (SDL). Then, we validate the designed models. We also detail a concrete implementation of the channel on an embedded chip that aims to show the C2A interoperability concept feasibility.We also studied the mobility effects in the inter-vehicular communication through a hybrid approach mixing routing and location-based service. This approach provides a mechanism to reduce vehicle-tracking costs while increasing routing performances. Moreover, we compare two applications of this approach: Hybrid Routing and Grid Location Service (HRGLS) and Hybrid Routing and Hierarchical Location Service (HRHLS) with classical approaches to prove the added value. Then, this approach is improved with a mobility prediction algorithm. The latter allows a better understanding of the vehicle movements by estimating them. Similarly, the hybrid approach with mobility prediction Predictive Hybrid Routing and Hierarchical Location Service (PHRHLS) is compared with the basic approach and HRHLS in order to show the mobility prediction advantages.
82

A mobile toolkit and customised location server for the creation of cross-referencing location-based services

Ndakunda, Shange-Ishiwa Tangeni January 2013 (has links)
Although there are several Software Development kits and Application Programming Interfaces for client-side location-based services development, they mostly involve the creation of self-referencing location-based services. Self-referencing location-based services include services such as geocoding, reverse geocoding, route management and navigation which focus on satisfying the location-based requirements of a single mobile device. There is a lack of open-source Software Development Kits for the development of client-side location-based services that are cross-referencing. Cross-referencing location-based services are designed for the sharing of location information amongst different entities on a given network. This project was undertaken to assemble, through incremental prototyping, a client-side Java Micro Edition location-based services Software Development Kit and a Mobicents location server to aid mobile network operators and developers alike in the quick creation of the transport and privacy protection of cross-referencing location-based applications on Session Initiation Protocol bearer networks. The privacy of the location information is protected using geolocation policies. Developers do not need to have an understanding of Session Initiation Protocol event signaling specifications or of the XML Configuration Access Protocol to use the tools that we put together. The developed tools are later consolidated using two sample applications, the friend-finder and child-tracker services. Developer guidelines are also provided, to aid in using the provided tools.
83

Vliv nových médií na Sex Dating / The Impact of New Media on Sex Dating

Botha, Marek January 2015 (has links)
This thesis is about what it feels like to connect, or fail, during digital or face-to-face interaction. This study aims to investigate one of the types of social interaction - sex dating and examines the role and impact of location-based dating applications in current form. The practical part is based on qualitative research method in form of in-depth interview with 18 active users. It compares experience of heterosexual and homosexual users with this non-anonymous digital environment integrate individuals into a fluid virtual space. Powered by TCPDF (www.tcpdf.org)
84

Conceptual design and implementation of tutorials for app development in the context of the lecture 'Mobile Cartography'

Hartl, Maximilian 07 September 2012 (has links)
Mobile applications are becoming more and more important in the daily life and offer interesting and completely new aspects to the field of cartography. The technological possibilities provided by computer science have had a large impact on cartography and therefore cartographers must be familiar with the development of software to present geographic information and make it accessible. With the recent rise of mobile devices like smartphones, it is inevitable that this has to include mobile platforms as well. The main focus of this Bachelor thesis is on the conceptual design and implementation of tutorials to teach the development of mobile applications or 'apps' for the Android platform. The tutorials are going to be part of exercises in a practical course that accompanies the lecture 'Mobile Cartography' held at the Institute of Cartography at the Dresden University of Technology. Five exercises have been created covering key aspects of Android programming with Java. The theoretical part of this thesis starts with providing definitions of important terms of mobile computing and mobile cartography that will play an important role throughout the thesis. After that possibilities of interaction with mobile and web applications are introduced and discussed briefly. Location-based services and their usage in the context of social networks are discussed in the following section before the sensors of mobile devices are analyzed. A brief discussion of the potential for augmented reality applications is also given. The following second section deals with mobile software platforms and focuses on the Android operating system for mobile devices. Within this section, the features of the Android framework are described and some specific characteristics of software development are explained. The third section is all about the conceptual design and implementation of the tutorials. Considering the requirements for the practical course and different aspects of learning, the pedagogical approach is described. Additionally the ECLASS model which has evolved in the context of E-Learning is explained as it provided the structure of the exercises. After that, the content of the five exercises which include basics, layout, internal interaction of components, database access and the integration of maps is reflected. Finally, a brief outlook on further possible exercises is given.
85

Spatial Replay Protection for Proximity Services : Security and privacy aspects

Lindblom, Fredrik January 2016 (has links)
Proximity Services is a new feature in the 3rd Generation Partnership Project (3GPP) standard for mobile communication. This features gives the opportunity to provide services locally if the targets are sufficiently close. However, in the current version of the proposed specification, there is no protection against a malicious user tunneling messages to a remote location to give the impression of proximity. This thesis proposes solutions to protect against such a spatial replay attack and evaluates these solutions based on how the user’s integrity is preserved, their complexity, and the added overhead. It is not obvious today what the consequences of a spatial replay attack are and how serious such an attack could be. However, once the feature is deployed and people start using it, it could prove to be a major vulnerability. The methods presented in this thesis could be used to prevent spatial replay in 3GPP or similar standards proximity services. The chosen method is a geographical packet leash based on a poly-cylindrical grid for which only a certain amount of Least Significant Bits of the grid cell identifier is included in the initial Discovery Message and the rest could be used in the calculation of the Message Authentication Code. / Proximity Services är en ny funktion inom 3rd Generation Partnership Project (3GPP) standard för mobil kommunikation. Den möjliggör att erbjuda tjänster lokalt om de tänkta användarna är tillräckligt nära. I den nuvarande versionen av specifikationen så finns det dock inget som hindrar en tredje part med onda avsikter från att tunnla meddelanden från den ursprungliga platsen till en annan som inte är i närheten för att ge intrycket till mottagaren att sändaren finns nära. Det här examensarbetet föreslår lösningar för att begränsa nämnda attack och utvärderar dem efter hur de påverkar användarnas platssekretess, lösningens komplexitet och den overhead de innebär. Det är idag inte uppenbart på vilket sätt den nämnda attacken skulle kunna påverka användarna och hur allvarliga konsekvenserna kan bli, men när standarden är implementerad och eventuella användare tillkommer så skulle det kunna visa sig innebära en stor risk. Lösningarna som presenteras i det här examensarbetet skulle kunna användas för att begränsa den här typen av attacker inom 3GPPs standard eller liknande baserade på närhet. Den metoden som har valts är ett ’geographical packet leash’ baserat på ett polycylindriskt rutnät för vilket endast en bestämd mängd minst signifikanta bitar är inkluderade i ett inledande Discovery Message medans resten kan användas i beräkningen av Message Authentication Code.
86

Achieving Perfect Location Privacy in Wireless Devices Using Anonymization

Montazeri, Zarrin 24 March 2017 (has links)
The popularity of mobile devices and location-based services (LBS) have created great concerns regarding the location privacy of the users of such devices and services. Anonymization is a common technique that is often being used to protect the location privacy of LBS users. This technique assigns a random pseudonym to each user and these pseudonyms can change over time. Here, we provide a general information theoretic definition for perfect location privacy and prove that perfect location privacy is achievable for mobile devices when using the anonymization technique appropriately. First, we assume that the user’s current location is independent from her past locations. Using this i.i.d model, we show that if the pseudonym of the user is changed before O(n2/(r−1)) number of anonymized observations is made by the adversary for that user, then she has perfect location privacy, where n is the number of users in the network and r is the number of all possible locations that the user might occupy. Then, we model each user’s movement by a Markov chain so that a user’s current location depends on his previous locations, which is a more realistic model when approximating real world data. We show that perfect location privacy is achievable in this model if the pseudonym of the user is changed before O(n2/(|E|−r)) anonymized observations is collected by the adversary for that user where |E| is the number of edges in the user’s Markov model.
87

Exploring Techniques for Providing Privacy in Location-Based Services Nearest Neighbor Query

Asanya, John-Charles 01 January 2015 (has links)
Increasing numbers of people are subscribing to location-based services, but as the popularity grows so are the privacy concerns. Varieties of research exist to address these privacy concerns. Each technique tries to address different models with which location-based services respond to subscribers. In this work, we present ideas to address privacy concerns for the two main models namely: the snapshot nearest neighbor query model and the continuous nearest neighbor query model. First, we address snapshot nearest neighbor query model where location-based services response represents a snapshot of point in time. In this model, we introduce a novel idea based on the concept of an open set in a topological space where points belongs to a subset called neighborhood of a point. We extend this concept to provide anonymity to real objects where each object belongs to a disjointed neighborhood such that each neighborhood contains a single object. To help identify the objects, we implement a database which dynamically scales in direct proportion with the size of the neighborhood. To retrieve information secretly and allow the database to expose only requested information, private information retrieval protocols are executed twice on the data. Our study of the implementation shows that the concept of a single object neighborhood is able to efficiently scale the database with the objects in the area. The size of the database grows with the size of the grid and the objects covered by the location-based services. Typically, creating neighborhoods, computing distances between objects in the area, and running private information retrieval protocols causes the CPU to respond slowly with this increase in database size. In order to handle a large number of objects, we explore the concept of kernel and parallel computing in GPU. We develop GPU parallel implementation of the snapshot query to handle large number of objects. In our experiment, we exploit parameter tuning. The results show that with parameter tuning and parallel computing power of GPU we are able to significantly reduce the response time as the number of objects increases. To determine response time of an application without knowledge of the intricacies of GPU architecture, we extend our analysis to predict GPU execution time. We develop the run time equation for an operation and extrapolate the run time for a problem set based on the equation, and then we provide a model to predict GPU response time. As an alternative, the snapshot nearest neighbor query privacy problem can be addressed using secure hardware computing which can eliminate the need for protecting the rest of the sub-system, minimize resource usage and network transmission time. In this approach, a secure coprocessor is used to provide privacy. We process all information inside the coprocessor to deny adversaries access to any private information. To obfuscate access pattern to external memory location, we use oblivious random access memory methodology to access the server. Experimental evaluation shows that using a secure coprocessor reduces resource usage and query response time as the size of the coverage area and objects increases. Second, we address privacy concerns in the continuous nearest neighbor query model where location-based services automatically respond to a change in object*s location. In this model, we present solutions for two different types known as moving query static object and moving query moving object. For the solutions, we propose plane partition using a Voronoi diagram, and a continuous fractal space filling curve using a Hilbert curve order to create a continuous nearest neighbor relationship between the points of interest in a path. Specifically, space filling curve results in multi-dimensional to 1-dimensional object mapping where values are assigned to the objects based on proximity. To prevent subscribers from issuing a query each time there is a change in location and to reduce the response time, we introduce the concept of transition and update time to indicate where and when the nearest neighbor changes. We also introduce a database that dynamically scales with the size of the objects in a path to help obscure and relate objects. By executing the private information retrieval protocol twice on the data, the user secretly retrieves requested information from the database. The results of our experiment show that using plane partitioning and a fractal space filling curve to create nearest neighbor relationships with transition time between objects reduces the total response time.
88

Asset tracking, monitoring and recovery system based on hybrid radio frequency identification and global positioning system technologies

Matshego, Itumeleng Olebogeng January 2021 (has links)
M. Tech. (Department of Information Technology, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Tracking involves information gathering, manipulation and proving information on the location of a set item. Many single or hybrid technologies – Global Positioning System (GPS), Radio Frequency (RF), Bluetooth (BLT) or Wireless Fidelity (WiFi) – have been used to provide tracking information of an asset of interest. The use of hybrid technology in tracking assets has proven to be effective if the selection of the technologies used is done correctly. This study used a hybrid of GPS and Radio Frequency technologies to track assets of interest because of their characteristics for use inside and outside a building. In this study GPS geo-fencing was used and time interval was used to receive data from the technology. Heuristic methodology, which enabled us to divide a room into sections, was used, where testing was done in sections in a room with different types of material, such as bricks, wood or metal, and the RF signal degradation, called attenuation, was measured. A straight-line distance and a sum of distances at 30-minute intervals were calculated to determine how far the asset had travelled from the point of origin to the new position. A distance of less than 10 metres was ignored. Geofencing was used to trigger an event since it indicates that the asset has crossed the permitted boundary. An RF reader was placed at the door to identify when the asset left a building and triggered an event. A model was used for searching for a missing item in a room. The results showed that the system was able to produce two distances, one straight-line distance and the other the approximate sum distance travelled by the asset in 30-minute intervals. The RF model was able to find an asset in a room filled with different materials.
89

Gobuddy - Android mobile application

Nellaiappan, Kalaivani 01 January 2011 (has links)
The purpose of this application is to serve the end user of an Android Smart phone, with reliable, instantaneous and location based information on places of interest such as restaurants, gas stations, hotels, movie theaters, and the like by using the phones' built-in GPS. The basic information includes viewing the map and address of the place of interest and getting the directions to a particular place in addition to having some extra features. Contains computer source code.
90

Wireless privacy and personalized location-based services: the challenge of translating the legal framework into business practices

Gratton, Eloïse 08 1900 (has links)
L'avancement des communications sans-fil permet l'obtention de nouveaux services bases sur l'habileté des fournisseurs de services sans-fil à déterminer avec précision, et avec l'utilisation de technologies de pistage, la localisation et position géographiquement d'appareils sans-fil Cette habileté permet d'offrir aux utilisateurs de sans-fil de nouveaux services bases sur la localisation et la position géographique de leur appareil. Le développement des services basés sur la localisation des utilisateurs de sans-fil soulevé certains problèmes relatifs à la protection de la vie privée qui doivent être considérés. En effet, l'appareil sans-fil qui suit et enregistre les mouvements de I 'utilisateur permet un système qui enregistre et entrepose tous les mouvements et activités d'un tel utilisateur ou encore qui permet l'envoi de messages non anticipes à ce dernier. Pour ce motif et afin de protéger la vie privée des utilisateurs de sans-fil, une compagnie désirant développer ou déployer une technologie permettant d'offrir ce genre de services personnalisés devra analyser l'encadrement légal touchant la protection des données personnelles--lequel est dans certains cas vague et non approprié à ce nouveau contexte--ainsi que la position de l'industrie dans ce domaine, et ce, afin d'être en mesure de traduire cet encadrement en pratiques commerciales. Cette analyse permettra d'éclairer le fournisseur de ces services sur la façon d'établir son modèle d'affaires et sur le type de technologie à développer afin d'être en mesure de remédier aux nouveaux problèmes touchant la vie privée tout en offrant ces nouveaux services aux utilisateurs de sans-fil. / The proliferation of mobile communications is leading to new services based on the ability of service providers to determine, with increasing precision and through the use of location determination technologies, the geographic location of wireless devices and allow their users to receive services based on such location. The development of location-based services introduces new privacy risks for consumers that must be addressed. The portability of wireless devices coupled with their ability to pinpoint the location of wireless users and reveal it to others could produce a system where the everyday activities and movements of these users are tracked and recorded, and where wireless users receive unanticipated messages on their device. For this reason and in order to preserve the privacy of wireless users, a company looking to deploy a technology related to the providing of personalized location-based services ("LBS Provider") will have to analyze the privacy legal framework, coming either from legal sources--that may be in some case vague and not specific to this new context--or from the industry, and translate such framework into business practices. Such analysis may help in establishing what kind of business model and technology should be adopted and developed by LBS Providers in order to ensure the privacy of wireless users while providing this new type of service.

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