The thesis formulates effective strategies for delivery of streaming content for mobile users in resource-limited networks. We consider the entire end-to-end delivery path from the source to the destination. In the work, we take into account 1) the presence of a large number of mobile devices operating inside an area with overlapping coverage of several mobile networks; and 2) the ability of the mobile devices to exploit several network technologies and to be connected to different access points simultaneously. We aim to improve the performance of the whole system by jointly considering users’ requirements and network limitations and by identifying and implementing adaptation mechanisms for different parts of the delivery path. Taking into account the complexity of the whole system, the thesis aims to design mechanisms operating in a decentralized manner with partial knowledge of the system. For this purpose, we study the ADIMUS architecture which addresses the problem of distributing streaming content for mobile users. The ADIMUS architecture clearly separates the system into two distinct parts: the backbone part of the network and the wireless part. We study resource adaptation mechanisms for both of these parts that include 1) overlay routing for the backbone and 2) multi-access approaches for heterogeneous wireless network. For overlay routing in the backbone, we consider multipath streaming techniques. For the wireless part, we improve the utilization of resources by intelligently redistributing mobile devices among the available wireless connections. To evaluate the adaptation mechanisms for both of these parts, we build mathematical models for the overlay network and for the heterogeneous wireless network. These mathematical models are used as upper bounds for operation of the adaptation solutions. We also define the lower bounds to these solutions based on earlier proposed solutions from the literature. For the overlay network, we develop and evaluate a distributed rate-allocation algorithm for delivery of video in a Video-on-Demand (VoD) system built upon multipath delivery. The algorithm’s operation is based on information collected by overlay nodes. The algorithm is evaluated in the OMNet++ simulation environment and analyzed against the aforementioned lower and upper bounds. We show that the algorithm performs close to the optimal solution in terms of proportionally fair bandwidth allocation between receivers of the overlay part of the architecture. For the heterogeneous wireless network, we consider the network selection to use for multiuser environments with possible multicast configurations that allows the network to perform load balancing, improve the users’ overall QoS, and increase the throughput of the networks. The novelty of the proposed solutions is that the network selection is done in a decentralized manner with only limited information available to decision makers. The solutions are evaluated through multiple simulations. We show that the solutions provide a substantial improvement in performance compared to their lower bounds. We also investigate a multiple connection approach for multicast groups with mobile terminals connecting to several networks simultaneously and receiving data through multiple paths. We show that the total usage of resources is reduced compared to a single path approach
Historisk befolkningsregister, HBR, er et register over den norske befolkningen fra 1801 frem til Det sentrale folkeregisteret fra 1964. Det lages ved å lenke sammen personforekomster av samme person i folketellinger og kirkebøker og koble sammen naere familiemedlemmer. Vi viser hvordan algoritmer brukes til å finne lenker og koblinger. Vi har funnet familierelasjoner i alle de nominative folketellingene, også der familiestilling ikke er beskrevet i folketellingen. Alle algoritmene baserer seg på likhet i navn, fødselsår, fødested, yrke, bosted og tilsvarende egenskaper hos familiemedlemmer. I tillegg sjekker vi at alle hendelsene gir et naturlig livsløp. Algoritmene må tilpasses de ulike kildene for å holde feilraten under en teoretisk målsetning på 1 %-noen fasit fins imidlertid ikke. Vi må for eksempel ha strengere kriterier for likhet i store kommuner som Oslo, enn i mindre kommuner og strengere i 1865
Using a Petri net engine to manage workflow processes requires additional interfacing software to connect the Petri net to the real world. Furthermore, changes in the real world or in the process model must often be reflected in the interfacing software, thus creating a potential consistency problem. We present a Petri net-based software architecture in which workflow processes are described as Petri nets, and where the relationships between Petri net parts and real world entities are described as metadata in the Petri net, thereby making the interfacing software generic as well as eliminating the consistency problem. The core element of the architecture is a Petri net engine that allows metadata to be stored in hierarchical colored Petri nets. Another element of the architecture is a generic interface process that queries the Petri net for its contained metadata that describes how to communicate with the real world entities. Finally, the architecture contains a set of communication protocols that are used for the real world communication. As an example we present an application from the printing industry.