<p>As the development of context aware applications has evolved, there has been a corresponding increase in need for more sophisticated system. The aim for this thesis is the development of a dynamical P2P network system which is based on locations. The P2P network is self organizing and in a lightweight format. Modern technical solutions including   AGPS have facilitated the work associated with the ability to position users and modern mathematical solutions such as spherical trigonometry provides the P2P system with the necessary accuracy even for short distances. The P2P system works on different Java platforms including JSE, JME and Android. Unfortunately the 3G network distributor has not yet solved a NAT traversal problem, which means that the P2P network self organization and architecture has only been proved by means of simulations. Another problem is that certain mathematical formulas are required for the spherical trigonometry and the limitation for JME is that it is unable to handle inverse trigonometry. However, the Android and JSE versions can form a correct P2P network, under the condition that the Android device uses a WIFI connection point outside the 3G distributor network system. This thesis reports the successful testing of the locations-based P2P network.</p> / MediaSense

As the development of context aware applications has evolved, there has been a corresponding increase in need for more sophisticated system. The aim for this thesis is the development of a dynamical P2P network system which is based on locations. The P2P network is self organizing and in a lightweight format. Modern technical solutions including   AGPS have facilitated the work associated with the ability to position users and modern mathematical solutions such as spherical trigonometry provides the P2P system with the necessary accuracy even for short distances. The P2P system works on different Java platforms including JSE, JME and Android. Unfortunately the 3G network distributor has not yet solved a NAT traversal problem, which means that the P2P network self organization and architecture has only been proved by means of simulations. Another problem is that certain mathematical formulas are required for the spherical trigonometry and the limitation for JME is that it is unable to handle inverse trigonometry. However, the Android and JSE versions can form a correct P2P network, under the condition that the Android device uses a WIFI connection point outside the 3G distributor network system. This thesis reports the successful testing of the locations-based P2P network. / MediaSense

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.