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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.
261

Réseaux pilotés par logiciels efficaces en énergie / Energy efficient software defined networks

Huin, Nicolas 28 September 2017 (has links)
Au cours des dernières années, la croissance des architectures de réseaux de télécommunication a rapidement augmenté pour suivre un trafic en plein essor. En outre, leur consommation d'énergie est devenue un enjeu Important, tant pour son impact économique qu'écologique. De multiples approches ont été proposées pour la réduire. Dans cette thèse, nous nous concentrons sur l'approche Energy Aware Routing (EAR) qui consiste à fournir un routage valide tout en diminuant le nombre d'équipements réseau actifs. Cependant, les réseaux actuels ne sont pas adaptés au déploiement de politiques vertes globales en raison de leur gestion distribuée et de la nature fermée des périphériques réseau actuels. Les paradigmes de Software Defined Network (SDN) et de Network Function Virtualization (NFV) promettent de faciliter le déploiement de politiques vertes. En effet, le premier sépare le plan de contrôle et de données et offre donc une gestion centralisée du réseau. Le second propose de découpler le logiciel et le matériel des fonctions réseau et permet une plus grande flexibilité dans la création et la gestion des services réseau. Dans cette thèse, nous nous concentrons sur les défis posés par ces paradigmes pour le déploiement de politiques EAR. Nous consacrons les deux premières parties aux SDNs. Nous étudions d'abord les contraintes de taille de table de routage causées par la complexité accrue des règles, puis le déploiement progressif de périphériques SDN dans un réseau actuel. Nous concentrons notre attention sur NFV dans la dernière partie, et plus particulièrement nous étudions les chaines de fonctions de services. / In the recent years, the growth of the architecture of telecommunication networks has been quickly increasing to keep up with a booming traffic. Moreover, the energy consumption of these infrastructures is becoming a growing issue, both for its economic and ecological impact. Multiple approaches were proposed to reduce the networks' power consumption such as decreasing the number of active elements. Indeed, networks are designed to handle high traffic, e.g., during the day, but are over-provisioned during the night. In this thesis, we focus on disabling links and routers inside the network while keeping a valid routing. This approach is known as Energy Aware Routing (EAR). However current networks are not adapted to support the deployment of network-wide green policies due to their distributed management and the black-box nature of current network devices. The SDN and NFV paradigms bear the promise of bringing green policies to reality. The first one decouples the control and data plane and thus enable a centralized control of the network. The second one proposes to decouple the software and hardware of network functions and allows more flexibility in the creation and management of network services. In this thesis, we focus on the challenges brought by these two paradigms for the deployment of EAR policies. We dedicated the first two parts to the SDN paradigm. We first study the forwarding table size constraints due to an Increased complexity of rules. We then study the progressive deployment of SDN devices alongside legacy ones. We focus our attention on the NFV paradigm in the last part, and more particularly, we study the Service Function Chaining problem.
262

Tracking Online Trend Locations using a Geo-Aware Topic Model

Schreiber, Jonah January 2016 (has links)
In automatically categorizing massive corpora of text, various topic models have been applied with good success. Much work has been done on applying machine learning and NLP methods on Internet media, such as Twitter, to survey online discussion. However, less focus has been placed on studying how geographical locations discussed in online fora evolve over time, and even less on associating such location trends with topics. Can online discussions be geographically tracked over time? This thesis attempts to answer this question by evaluating a geo-aware Streaming Latent Dirichlet Allocation (SLDA) implementation which can recognize location terms in text. We show how the model can predict time-dependent locations of the 2016 American primaries by automatic discovery of election topics in various Twitter corpora, and deduce locations over time.
263

In Search for Gender awareness in Technology Education

Rooke, Gunilla January 2013 (has links)
This thesis consists of two essays and an introduction. The main theme is gender awareness in technology education and the theoretical standpoint is gender theory. The first essay examines the subject of technology in compulsory school, scrutinizes the status of gender awareness in technology education and what methods are used to break gender boundaries. By observations, interviews and questionnaire pupils’, teachers’ and school leaders’ apprehensions of technology and technology education are examined. The gender issue is known to everyone, but awareness in strategies and education methods is rather deficient. The already rather invisible subject of technology, lack of qualifications among teachers, material and methods obstructs gender awareness. To make changes the school leader has a key position. The second essay considers gender oriental recruitment actions for increasing the number of female students in higher technology education. The actions have been governmental, from the profession and from local schools. By literature studies actions are mapped and organized according to their physical and structural arena. Five arenas have been identified: square, mass, entrance, class room and board room. Actions at public arenas aimed to increase interest and change attitudes dominate. Structural actions, preferably initiated from the government, have been tried, often with good results. These actions challenge the power system at the board room and class room and are therefore met with resistance. / <p>QC 20130604</p>
264

Exploiting Presence

Wang, Ke January 2008 (has links)
By exploiting context awareness, traditional applications can be extended to offer better quality or new functions. Utilizing a context-aware infrastructure, a variety of context information is merged and processed to produce information that is useful to applications. Applications exploiting such context can provide more intelligent and creative services to end users. This thesis examines two ways to make use of a user’s location along with room occupancy information in context aware applications: a Context Agent and a Call Secretary. In the former case, the application subscribes to room occupancy information via a context server, and provides a Meeting Room Booking System with “real-time” information about the utilization of the rooms which the room booking system is to manage. The Call Secretary acquires both location and room occupancy information from a server. When the user is in one of the meeting rooms and multiple people are present, then this is interpreted as the user being in a meeting -- therefore it triggers a CPL module in a SIP proxy to redirect the user’s incoming call to their voice mail box. A description of the implementation of these two applications will be presented along with an evaluation of these applications’ performance. The evaluation of the Context Agent showed that it was straightforward to integrate information from a presence source and to extend the meeting room booking system to use this information. The Call Secretary needs a more reliable source for the user's location. However, given this location the Call Secretary provides the service which the user expects. / Genom att utnyttja sammanhang medvetenhet, traditionella tillämpningar kan utvidgas till att erbjuda bättre kvalitet eller nya funktioner. Använda en kontextmedvetna infrastruktur, en rad olika kontextuppgifter är sammanslagna och bearbetas för att producera information som är användbar för tillämpningar. Tillämpningar som utnyttjar sådana sammanhang kan ge mer intelligenta och kreativa tjänster till slutanvändare. Denna avhandling undersöker två sätt att använda sig av ett användaren befinner sig längs med rummet beläggningen information i samband medveten program: ett sammanhang av ombud och en uppmaning Sekreterare. I det förra fallet skall ansökan under på rumspris information via ett sammanhang server, och ger ett mötesrum bokningssystem med "realtid" information om användningen av de rum som lokalbokning system är att hantera. Ring sekreterare förvärvar både plats och rumspris information från en server. När användaren är i en av konferenslokaler och flera människor är närvarande, så är det tolkas som att användarna är i ett möte - därför det utlöser en CPL-modul i en SIP-proxy för att dirigera om användarens inkommande samtal till deras telefonsvarare fält. En beskrivning av genomförandet av dessa två program kommer att presenteras tillsammans med en utvärdering av dessa ansökningar resultat. Utvärderingen av det sammanhang ombud visade att det var enkelt att integrera information från en närvaro källa och att utvidga mötesrum bokningssystem att använda denna information. Ring sekreterare behöver en mer tillförlitlig källa för användarens plats. Med tanke på denna plats för samtal sekreterare tillhandahåller tjänster som användaren förväntar sig.
265

Context-aware applications for a Pocket PC

Sun, Yu January 2007 (has links)
With the rapid development of technology for context awareness, pervasive computing is releasing people from their traditional desktops. Since mobile devices feature portability and are (nearly) always connected, people tend to carry them wherever they go. Hence, devices such as cellular phones and Pocket PCs are the most suitable platforms for developing context aware applications which users will utilize in their daily life. For these context aware systems, using this context information not only improves the user experience of ubiquitous computing, but also lets the system know who you are or what you have. More importantly, the device can know where you are and predict what you might like to do, thus simplifying many of the user’s interactions with devices and other people around them. This thesis project involves the design, implementation and evaluation of a context aware application, based upon a Pocket PC, that can remind the user of tasks when the user approaches the relevant location for this task. The application interacts with a context aware infrastructure by using the SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) protocol, receives context information for the user described using XML. A number of new tags, based upon a new XML schema, have been introduced for this task. This context aware mechanism enables the user to receive any form of information updated by the context server. In this thesis, updates to this information are driven by changes in the user’s location. Additionally, by using the existing calendar application on the Pocket PC, the user can experience location based reminders without learning how to use a new user interface. / Med den snabba utvecklingen av kontextmedvetna teknologier befriar den genomträngande datoriseringen människor från deras traditionella datorer. Eftersom mobila apparater medför bärbarhet och är (nästan) alltid uppkopplade, tenderar människor att bära dem överallt. Följaktligen blir apparater som mobiltelefoner och Pocket-PC de mest passande plattformarna för utvecklandet avkontextmedvetna applikationer för daglig användning. För dessa kontextmedvetna system kommer inte bara användandet av kontexinformation förbättra användarens upplevelse av överallt förekommande datorisering, utan låter även systemet veta vem du är eller vad du har. ännu viktigare är att apparaten kan veta var du befinner dig samt förutsäga vad du skulle kunna vilja göra, och därigenom förenkla mycket av användarens interaktion med andra apparater och människor i omgivningen. Detta examensarbetsprojekt involverar designen, implementationen och evalueringen av en kontextmedvetet applikation, baserad på en Pocket-PC, som kan påminna användaren om uppgifter när användaren närmar sig det relevanta området för dessa uppgifter. Applikationen interagerar med en kontextmedveten infrastruktur genom användandet av protokollet “SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE)”, mottas kontextinformation för användaren beskriven i XML-format. Ett antal nya taggar, baserade på en ny XML-schema, har introducerats för denna uppgift. Denna kontextmedvetna mekanism gör det möjligt för användaren att ta emot alla typer av uppdaterad information från kontextservern. I denna avhandling uppdateras denna information genom att användaren förflyttar sig. Dessutom kan användaren, genom att använda den befintliga kalenderapplikationen i Pocket-PC:n, få lägesbaserade påminnelser skickade till sig utan att behöva lära sig använda ännu ett interface.
266

A Distributed Approach to Context-Aware Networks : Prototype System Design, Implementation, and Evaluation

Swenson, Markus January 2007 (has links)
Utilizing context information and in networks, enabling network services to act upon context information, and exchanging context information with applications, constitutes an important new approach to designing communication systems and central to the research project named Ambient Networks. The Ambient Networks project is a part of the 6th Framework Project cofunded by the European Commission and carried out by industry and academia. A system is said to be context-aware when it reacts to changes in context i.e., information which describes an entity’s current situation. This new approach enables developments of systems that are more adaptive to user needs and behavior. As a result systems can provide a homogenous appearance which is important as more and more different network access technologies arise. This thesis investigates, models, implements, and evaluates a distributed context-aware architecture for Ambient Networks, the Distributed Context eXchange Protocol (DCXP). The solution is a proof-of-concept that shows how a context-aware ambient network can benefit from a distributed approach. The current design is based on a peer-to-peer architecture that forms an overlay to distribute context information among the participating units. This distributed approach was chosen in order to balance the load and also enable a device to easily locate and fetch desired context information. The evaluation of the proposed context-aware architecture addresses the issues of how such a system ties in with the ideas of Ambient Networks. The main result of this report is a prototype enabling nodes in an ambient network to exchange context information. Moreover, the results show that the prototype needs to be refined in order to work in larger scale networks. / Användning av miljö-beskrivande information, så kallad context information, i olika nätverk är en ny infallsvinkel i designen av kommunikationssystem och är av stor vikt i forskningsprojektet Ambient Networks. Målet är att context information ska kunna utnyttjas i nätverken av olika tjänster samt även dela informationen med applikationer. Ambient Networks projektet är en del av det sjätte EU finansierade ramprogrammet där industrin och den akademiska världen deltar. Ett nätverk eller system klassificeras som context medvetet, context-aware, när det tar hänsyn till förändringar i sk. context information. Context information eller miljö-beskrivande information beskriver en enhets nuvarande situation. Detta möjliggör utveckling av system som ”lyssnar” på användaren och anpassar sig efter dess behov och beteende. Ett praktiskt exempel skulle kunna vara att användare upplever det som ett homogent system trots att det finns flera underliggande access teknologier. Den här uppsatsen undersöker, designar, implementerar och utvärderar en distribuerad context-aware arkitektur för Ambient Networks, Distributed Context eXchange Protocol (DCXP). Lösningen visar hur ett ambient network kan nyttja en distribuerad lösning för att hantera context information. Designen bygger på att de deltagande noderna skapar ett virtuellt nät, overlay, för att mellan sig dela på context informationen. Den här lösningen valdes för att balansera belastningen jämt mellan de deltagande noderna samt att på ett enkelt sätt för varje enskild node kunna lokalisera och hämta önskad context information. Utvärdering av den föreslagna lösningen visar på hur den kan integreras med den övriga utvecklingen som skett inom Ambient Networks projektet. Det huvudsakliga resultatet av arbetet är en prototyp som möjliggör för noder i ett ambient nätverk att utbyta context information. Vidare visar även resultatet att prototypen bör vidareutvecklas för att fungera i större sammanhang.
267

Position Determination using multiple wireless interfaces

Hassellöf, Daniel January 2008 (has links)
This Master’s thesis studies different ways of exploiting the signal strength measurements from wireless interfaces for position determination. Difficulties include handling the fluctuating observations and their sensitivity to obstruction. We list important factors to take into account before describing a new system based on location fingerprinting and capable of integrating observations from multiple wireless interfaces. Compared to typical fingerprinting solutions, the training time is an order of magnitude shorter, but the location resolution is limited to locations of particular interest. In an office environment, the proposed solution determines the location correctly 80 percent of the time with sufficient precision for being used with context-aware services. In an open space environment, an incorrect location is reported 42 percent of the time. / Det här exjobbet studerar olika sätt att använda signalstyrka från trådlösa gränssnitt för positionsbestämning. Några av svårigheterna ligger i att hantera observationernas fluktuationer och deras känslighet för obstruktion. De viktigaste faktorerna att ta hänsyn till tas upp innan ett nytt system beskrivs. Det är baserat på positionsigenkänning (location fingerprinting) och kan dra nytta av observationer från flera olika trådlösa gränssnitt. Jämfört med vanliga metoder för positionsigenkänning är träningstiden en storleksordning kortare, men positionsupplösningen är begränsad till ett visst antal positioner av särskilt värde. I en kontorsmiljö klarar den föreslagna lösningen att korrekt bestämma positionen i 80 procent av fallen med tillräckligt hög noggrannhet för att användas till kontextmedvetna tjänster (context-aware services). I en öppen rumslösning ger lösningen en felaktig position i 42 procent av fallen.
268

In-building Location Sensing Based on WLAN Signal Strength : Realizing a Presence User Agent

Shiode, Haruumi January 2008 (has links)
Exploiting context-aware environments, where sensors scattered in a environment update presence servers to indicate the environmental changes can be used to enable new services. Such systems have become feasible both in terms of technical di±culties and their cost. A current focus in this area of research is how a context-aware system should be designed so that it reduces both the cost and complexity of the infrastructure, but still provides the desired services. One of the key components of many context-aware systems is location sensing, because a user's location is one of the most used elements of information in context-aware services. In this paper, we address cost e®ective location services by utilizing measurements of WLAN signal strength. We derive from these measurements an estimate of a device's location, and make this location information available via a SIP Presence User Agent, thus making location information readily available to services that might wish to use this information - while hiding details of how this information is acquired from these services. / Genom att utnyttja kontextmedvetna miljöer, där sensorer i en miljö uppdaterar närvarande servrar med information omändringar i omgivningen, så kan man öppna upp vägar för nya tjänster. Sådana system har blivit utförbara bade när det gäller tekniska svarigheter och deras kostnader. Inom forskning som rör sådana här system ägnas mycket uppmärksamhetåt hur en kontextmedveten miljö borde designas för att minimera både kostnaden och komplexiteten av infrastrukturen, men fortfarande tillhandahålla den önskade tjänsten. En av huvudkomponenterna i många kontextmedvetna system är platsuppfattning, eftersom en användares position är en av de mest använda elementen av information i kontextmedvetna tjänster. I den här uppsatsen ägnar vi oss åt kostnadseffektiva platstjänster genom att mäta signalstyrkan av ett WLAN. Genom dessa mätningar uppskattar vi en enhets position och gör denna information tillgänglig via en SIP Presence User Agent, och gör på så vis platsinformationen tillgänglig för tjänster som kan vilja ha den { utan att avslöja detaljer om hur informationen har skaffats.
269

Location Aware Communication

Eckerström, Johan January 2003 (has links)
Automotive telematic systems will be as common in future cars as ABS and airbags are in current cars. These systems will provide services such as navigation aid, automatic emergency alerts, traffic and road information, information about parking possibilities, tourist information, and personalized news. All these services need a communication link to the mobile Internet to be able to work properly. In this master’s thesis General Packet Radio Service, GPRS will be investigated and evaluated as a bearer for these kinds of services. A test application was built to test the location aware communication on the field. Upstream and downstream delays, possible bottlenecks in the network, connection set-up time, characteristics of different operators, and connection breakdowns where analyzed. The tests showed high network delays, and that many connection breakdowns occurred. The operators did not differ much when it comes to performance. One mayor drawback with GPRS is the low scalability with respect to operator’s lack of IP addresses, which will be discussed. Conclusions of the evaluation were that only certain location-based services are suitable over GPRS with the quality of today.
270

Improving Player Performance by Developing Gaze Aware Games

Navarro, Diego January 2014 (has links)
Context. Eye tracking technology has been applied to video games, mainly, as an offline analysis tool or as an input for game control. Nevertheless, eye tracking systems applied to video games is a topic considered to be on an infant state that requires further development. The following study explore a different approach in how eye tracking systems can be used for video game interaction. Objectives. By implementing a gaze based interaction technique, a gaze aware space shooting game will be developed in order to provide in-game assistance that could improve player&apos;s performance. Method. With the help of a Tobii REX eye traking system, a set of 26 volunteers played two video games in a controlled environment. Both of the games had the same mechanics and elements, but only one of them implemented the gaze based interaction technique. The player performance was calculated in terms of the time needed by the players to finish each of the games. A statistic significance analysis was done in order to determine if the testing data provided sufficient evidence to conclude a performance improvement. Results. The results showed a reduction on the time needed to finish the game on the gaze aware prototype, having an average time difference of 74.03 seconds and overcoming a confidence level of 99.9\% when submitting the testing data to a paired t-Test. Also, the majority of the players chose the gaze aware game as the most enjoyable, in terms of their personal preferences. Conclusions. The testing results provided sufficient evidence to conclude that the gaze aware game improved the performance of all of the selected participants. This study provides a starting point for further development of eye tracking systems as a task assisting method on video game interaction.

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