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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.
21

Models and algorithms for the combinatorial optimization of WLAN-based indoor positioning system / Modèles et algorithmes pour l'optimisation combinatoire de systèmes de localisation indoor basés sur les WLAN

Zheng, You 20 April 2012 (has links)
La localisation des personnes et des objets à l’intérieur des bâtiments basée sur les réseaux WLAN connaît un intérêt croissant depuis quelques années ; ce système peut être un parfait complément pour fournir des informations de localisation statique ou dynamique dans des environnements où les techniques de positionnement telles que GPS ne sont pas efficaces. Le manuscrit de thèse propose une nouvelle approche pour définir un système WLAN de positionnement indoor (WLAN-IPS) comme un problème d'optimisation combinatoire afin de garantir à la fois une qualité de communication et une minimisation de l'erreur de positionnement via le réseau. Cette approche est caractérisée par plusieurs questions difficiles que nous abordons en trois étapes.Dans un premier temps, nous avons conçu un réseau WLAN-IPS et mis en œuvre une plateforme de test. Nous avons examiné la performance du système sous diverses contraintes expérimentales et nous nous sommes penchés sur l'analyse des relations entre l'erreur de positionnement et les facteurs environnementaux externes. Ces relations ont permis de proposer des indicateurs pour évaluer l'erreur de positionnement. Ensuite nous avons proposé un modèle physique qui définit tous les paramètres majeurs rencontrés en WLAN-IPS à partir de la littérature. L'objectif initial des infrastructures WLAN étant de fournir un accès radio de qualité au réseau, nous avons introduit un objectif supplémentaire qui est de minimiser l'erreur de localisation dans le contexte IPS. Deux indicateurs principaux ont été définis afin d'évaluer la qualité de service (QoS) et l'erreur de localisation pour LBS (Location-Based Services). Enfin après avoir défini la formulation mathématique du problème d'optimisation et les indicateurs clés de performance, nous avons proposé un algorithme mono-objectif et un algorithme multicritère basés sur Tabu Search et Variable Neighborhood Search pour fournir des bonnes solutions en temps raisonnable. Les simulations montrent que ces deux algorithmes sont très efficaces pour le problème d'optimisation que nous avons posé. / Indoor Positioning Systems (IPS) using the existing WLAN have won growing interest in the last years, it can be a perfect supplement to provide location information of users in indoor environments where other positioning techniques such as GPS, are not much effective. The thesis manuscript proposes a new approach to define a WLAN-based indoor positioning system (WLAN-IPS) as a combinatorial optimization problem to guarantee the requested communication quality while optimizing the positioning error. This approach is characterised by several difficult issues we tackled in three steps.At first, we designed a WLAN-IPS and implemented it as a test framework. Using this framework, we looked at the system performance under various experimental constraints. Through these experiments, we went as far as possible in analysing the relationships between the positioning error and the external environmental factors. These relationships were considered as evaluation indicators of the positioning error. Secondly, we proposed a model that defines all major parameters met in the WLAN-IPS from the literature. As the original purpose of the WLAN infrastructures is to provide radio communication access, we introduced an additional purpose which is to minimize the location error within IPS context. Two main indicators were defined in order to evaluate the network Quality of Service (QoS) and the positioning error for Location-Based Service (LBS). Thirdly, after defining the mathematical formulation of the optimisation problem and the key performance indicators, we proposed a mono-objective algorithm and a multi-objective algorithm which are based on Tabu Search metaheuristic to provide good solutions within a reasonable amount of time. The simulations demonstrate that these two algorithms are highly efficient for the indoor positioning optimization problem.
22

Parallel reality : tandem exploration of real and virtual environments

Davies, C. J. January 2016 (has links)
Alternate realities have fascinated mankind since early prehistory and with the advent of the computer and the smartphone we have seen the rise of many different categories of alternate reality that seek to augment, diminish, mix with or ultimately replace our familiar real world in order to expand our capabilities and our understanding. This thesis presents parallel reality as a new category of alternate reality which further addresses the vacancy problem that manifests in many previous alternate reality experiences. Parallel reality describes systems comprising two environments that the user may freely switch between, one real and the other virtual, both complete unto themselves. Parallel reality is framed within the larger ecosystem of previously explored alternate realities through a thorough review of existing categorisation techniques and taxonomies, leading to the introduction of the combined Milgram/Waterworth model and an extended definition of the vacancy problem for better visualising experience in alternate reality systems. Investigation into whether an existing state of the art alternate reality modality (Situated Simulations) could allow for parallel reality investigation via the Virtual Time Windows project was followed by the development of a bespoke parallel reality platform called Mirrorshades, which combined the modern virtual reality hardware of the Oculus Rift with the novel indoor positioning system of IndoorAtlas. Users were thereby granted the ability to walk through their real environment and to at any point switch their view to the equivalent vantage point within an immersive virtual environment. The benefits that such a system provides by granting users the ability to mitigate the effects of the extended vacancy problem and explore parallel real and virtual environments in tandem was experimentally shown through application to a use case within the realm of cultural heritage at a 15th century chapel. Evaluation of these user studies lead to the establishment of a number of best practice recommendations for future parallel reality endeavours.
23

Populating a Database to be used with an Indoor Positioning System / Populera en databas som ska användas med ett inomhuspositioneringssystem

Halvarsson, Maria, Qin, Jinglan January 2022 (has links)
Indoor Positioning System (IPS) are becoming more common in many areas such as retail, warehouses, smart facilities, and manufacturing.In recent years, Bluetooth Low Energy (BLE)-based IPS has become increasingly popular due to its low cost and low energy consumption. One of the more recent updates, Bluetooth 5.1, provides the ability to compute the location using Angle of Arrival (AoA) or Angle of Departure (AoD). These new features have allowed for better positioning accuracies, where AoA-based positioning has shown sub-meter accuracy. An application area for BLE-based IPS is retail stores where the technology can benefit both the store and its customers. This thesis investigates how to populate a database to be used with an IPS in a real-life store. The assumption is that customers will have BLE equipped devices and run an application that will send the properly formatted BLE advertisements, such that an BLE IPS can locate the user in the store. Additionally, we assume that the application can use the device's e-compass or other means to determine in which direction the user's device is oriented. Based on the position and orientation of the user, the software is assumed to access a database to know what item(s) are near the customer. However, the question remains of how did this data get into the database? This degree project explores this in detail and assesses the amount of time and effort needed to populate this database and the amount of time and effort needed to keep this database up to date. This project followed an iterative Design Science Research (DSR) methodology where the artifact is the database. A relational database was used as they are widely used and joins can easily be performed and it is easy to modify existing tables. The application was developed in Spring Boot and React. Amazon Web Services (AWS) was used to host and provide the necessary services for the database and application. The result showed that the estimated time needed to populate the database in a supermarket with a sales area of 5300 m2, 36623 products, and 220 containers is 106.64 hours and 107.13 hours in the worst case assuming a walking speed of 1.4 m s-1. Updating a product would take 10.34 s and 10.37 s if the time it takes for a staff member to walk to the place where the product is located is excluded. / Inomhuspositioneringssystem (IPS) har blivit allt vanligare inom många områden. De senaste åren har Bluetooth Low Energy (BLE)-baserad inomhuspositionering blivit mer populärt på grund av egenskaper som låg kostnad och låg energikonsumption. En av de senaste versionerna; Bluetooth 5.1 kan beräkna positionen med hjälp av ankomstvinkeln (eng. Angle of Arrival (AoA)) och utgångsvinkeln (eng. Angle of Departure (AoD)). Angle of Arrival (AoA)-baserad positionering kan uppnå en noggrannhet under 1 m. Ett Bluetooth Low Energy (BLE)-baserat IPS kan tillämpas i butiker där det kan gynna både butikens medarbetare och dess kunder. Detta examensarbete kommer att undersöka hur en databas som ska användas med ett IPS i en butik kan populeras. Antagandet i detta projekt är att kunderna kommer ha BLE utrustade enheter som kör ett program som tillåter att användaren kan lokalisera sig i butiken. Dessutom antar vi att applikationen kan använda enhetens e-kompass eller annan hårdvara för att kunna avgöra i vilken riktning användarens enhet är orienterad. Baserat på användarens position och riktning, antas det att mjukvaran kan komma åt databasen och veta vilka produkter som ligger i närheten av kunden. Dock kvarstår frågan: Hur sparades denna data i databasen? Det här examensarbetet kommer alltså att undersöka hur en databas i en butik kan vara uppbyggd om vi utgår från antagandet att BLE är tillämpat i butiken. Vi kommer även bedöma hur mycket tid som krävs för att populera en databas och hålla denna databas uppdaterad. Ett iterativ arbetsätt tillämpades i examensarbetet. I projektet användes en relationsdatabas eftersom det är enkelt att utföra join-operationer och uppdatera tabbeller i databasen. Applikationen som skapades tillhandahåller funktioner för att spara, uppdatera, radera och söka produkter i databasen. Frontend var kodad i React och backend var kodad i Spring Boot. Amazon Web Services (AWS) molntjänser och deras verktyg användes för att köra applikationen och databasen. Resultatet visade att populera en databas med produkter i en mataffär med en säljyta på 5300 m2, 36623 produkter, och 220 behållare (hyllor, kylskåp, etc.) tog 106.64 timmar i bästa fall och 107.13 timmar i värsta fall om vi antar en gångfart i 1.4 m s-1.
24

Positioning and parking analysis for an indoor positioning system : A comparative study between Bluetooth Low Energy and Ultra Wideband technology / Positionerings- och parkeringsanalys för ett inomhuspositioneringssystem : En jämförande studie mellan Bluetooth Low Energy och Ultra Wideband teknologi

Brodin Kont, August January 2019 (has links)
The work done in this report as requested by H&D Wireless is performed by using an already developed real time positioning system called Griffin Enterprise Positioning Service and integratingit with ultrasound sensors for presence detection in order to enable assets to park in a visualized environment being actualized by tagging the asset with radio technology hardware. The testing environment was deployed with radio technology hardware equipped for transmitting and receiving radio signals for position estimation of tagged objects where hardware tags emits radio signals being received by sensing radio technology chips called sensepoints which also serves as communication links for further data processing.The thesis focus is on evaluating how different radio technologies combined with different positioning techniques perform in terms of accuracy and precision in positioning tests to assess eachones positioning performance characteristic and the technologies upsides and downsides.This was firstly evaluated by comparing three different technology positioning techniques based on one for Bluetooth Low Energy and two using Ultra Wideband technology being subject to generic tests including a static, dynamic and a walking positioning test for each technology.These initial tests were utilized as a foreground to evaluate which of the two positioning techniques based on Ultra Wideband technology that would compete in the parking tests alongside Bluetooth Low Energy that would serve as the primary objective to accomplish in the thesis.A final implication on parking tags between the two technologies is that Bluetooth Low Energy had to be implemented with higher requirement restrictions for parking due to insufficient relative accuracy and precision in parking positioning which also limited its ability to be parked in alternative manners explored but with power efficiency as a highly valuable aspect for consideration of this technology. Parking tag using Ultra Wideband technology proved highly successful as it saw large distance margins to be allowed parking in all test cases as well as exhibiting sufficient positioning performance to be considered for alternative parking methods without risk of exposure for failed attempts of parking. / Arbetet utfört i denna rapport på order av H&D Wireless utfördes genom att använda en redan utvecklat realtids positionerings tjänst vid namn Griffin Enterprise Positioning Service och integreradetta system med ultraljudssensorer för närvaro upptäckning för att på så sätt göra det möjligt för tillgångar att parkera i en visualiserad miljö möliggjord av att märkta tillgångar, också kallade taggar, med radioteknologisk hårdvara. Test miljön var utformad med radioteknologisk hårdvara föratt kunna sända och ta emot radio signaler för positionerings estimering av märkta objekt där dessa taggar utsänder radio signaler som upptas av kännande radioteknologiska chip som kallas för sensepoints vilka också tjänar som kommunikationslänkar för vidarearbetning av data.Uppsatsen fokuserar på att utvärder hur radioteknologierna Bluetooth Low Energy och Ultra Wideband tillsammans med förbestämda positionerings tekniker presterar i termer av noggranhet och precision i positionerings tester för att kunna bedöma varderas positionerings karakteristiska prestanda och teknologiernas fördelar och nackdelar. Detta påbörjades genom att utvärdera tre olika teknologiska positioneringstekniker baserade på en med Bluetooth Low Energy och två med Ultra Wideband teknologi som utsattes av generiska tester,som inkluderar ett statisk, dynamiskt och gående positionerings test genomfört för vardera teknologi. Dessa initiala tester användes som grund för att utvärdera vilka två av positionerings teknikerna baserade på Ultra Wideband teknologi som skulle utgöra kandidat i parkerings testerna vid sidan om Bluetooth Low Energy vilket var det primära målet att genomföra i uppsatsen.En följd av att parkera taggar mellan de två teknologierna var att Bluetooth Low Energy krävde högre restriktioner vid implementering för parkering eftersom den uppvisade relativ otillräcklig noggranhet och precision i dess parkerings positionering vilket också begränsade dess förmåga att kunna parkera med alternativ parkings metoder förslagna i rapporten medan dess låga effektförbrukning som en fördelaktig aspekt vid övervägande av tekniken. Att parkera en tagg med Ultra Wideband teknologi demonstrerade framgångsrika resultat då den såg stora avståndsmarginaler för att tillåtas parkera i alla testfall såväl som uppvisande av tillräcklig hög positionerings prestanda för att kunna övervägas med alternativa parkerings metoder utan risk för misslyckade försök till att bli parkerad.

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