Viser treff 581-600 av 640

    • Distributed OpenSceneGraph 

      Samuelsen, Thomas (Master thesis; Mastergradsoppgave, 2007)
      This thesis presents the design and implementation of Distributed OpenSceneGraph. Distributed OpenSceneGraph is a graphics visualization toolkit for distributed applications, in particular for tiled display wall systems. Distributed OpenSceneGraph allows for flexible and reasonably transparent development of distributed graphics applications by introducing the notion of distributed nodes into the ...
    • SymboL. Et symbolspråk for Symbo 

      Nilssen, Kai-Even (Master thesis; Mastergradsoppgave, 2007-05)
      I dag er elektronisk post en naturlig måte å kommunisere på. Dessverre er det enkelte brukergrupper som ikke kan utnytte denne teknologien. Vårt fokus er barn i alderen 4-8 år. Symbo prosjektet tar sikte på å gi disse brukerne muligheten til nettopp dette. Målet med dette prosjektet er å lage et symbolbasert språk kalt SymboL. Dette er en samling symboler som gjennom bruk gir et begrenset ...
    • Design and implementation of a prototype for capturing immediate user experiences 

      Ekvang, Espen (Master thesis; Mastergradsoppgave, 2007-06-01)
      Everywhere we go we are overwhelmed with impressions and experiences making our day. Research has proven these to change over time, thus psychologists and experimenters in surveys are interested in what a person actually experienced at a particular point in time, referred to as immediate experience. Whether it was as a reaction to some event or just at specific times during the day, is determined ...
    • A distributed and parallell robot environment for competitive search and rescue using a display wall for visualization 

      Skadsem, Marte Karidatter (Master thesis; Mastergradsoppgave, 2006-06-08)
      In this thesis we present the development of a distributed and parallel environment which offers functionality to robots to support them in their task performance. We want the environment to be a framework where students can experiment with robots, and in which we can arrange robot competitions. Our motivation for this thesis is an earlier developed robot system at our department. It was ...
    • Bilder og stedsinformasjon 

      Bjørnenak, Kai Arne (Master thesis; Mastergradsoppgave, 2006-12-15)
      Enorme mengder informasjon er tilgjengelig på internett for browsing og søk for folk på jakt etter informasjon. En økende del av denne informasjonsmengden er bilder, video og audio. Disse media-typene er ikke så lette å kategorisere og beskrive som en tekstlig ressurs. Vi trenger derfor nye metoder for å takle utfordringene denne fremveksten av nye media gir oss. Digitalt fotografi har hatt ...
    • Design and evaluation of a recommender system 

      Mortensen, Magnus (Master thesis; Mastergradsoppgave, 2007-02-05)
      In the recent years, the Web has undergone a tremendous growth regarding both content and users. This has lead to an information overload problem in which people are finding it increasingly difficult to locate the right information at the right time. Recommender systems have been developed to address this problem, by guiding users through the big ocean of information. Until now, recommender systems ...
    • A multiagent architecture for a distributed artificial intelligence application 

      Hartvigsen, Gunnar; Johansen, Dag (Research report; Forskningsrapport, 1990)
      Artificial intelligence applications are normally complex, demanding much computing power. This paper presents the multiagent architecture of StormCast, a distributed artificial intelligence application for severe storm forecasting. Important objectives as scaleability, robustness and reusability can be met by partitioning an ove rall task in subtasks, distribution of the subtasks on different nodes, ...
    • Cooperation through information interchange in StormCast 

      Hartvigsen, Gunnar; Johansen, Dag (Research report; Forskningsrapport, 1990)
      This paper addresses the cooperation between different expert system modules in a networking environment. StormCast - a distributed artificial intelligence application for severe storm forecasting is used as a case to obtain practical results. Two key aspects is investigated, first the representation of knowledge in this kind of environment is outlined. Then the cooperating nature of a group of ...
    • StormVideo - digital video in the field of meteorology 

      Nybø, Olav; Hartvigsen, Gunnar; Johansen, Dag (Research report; Forskningsrapport, 1994-09)
      Visual observations constitute important input to different meteorological tasks. Previously, these observations were made by human observers and manually reported to the meteorologists. With the employment of video technology, this kind of observations can be automated. This paper presents one approach to visual weather observations. This involves software compression and transmission of digital ...
    • An extensible software architecture for mobile components 

      Marzullo, Keith; Johansen, Dag; Lauvset, Kåre J. (Research report; Forskningsrapport, 2000-10-06)
      This paper presents a generic software architecture for large-scale distributed applications where mobile agents are an integral part. We have devised this architecture through completion of a series of mobile agent systems and associated applications over the last 8 years.
    • Building agent applications using wrappers 

      Sudmann, Nils P.; Johansen, Dag (Research report; Forskningsrapport, 2001-01-11)
      For the past seven years, the TACOMA project has investigated software support for mobile agents. Several prototypes have been developed, with experiences in distributed applications directing the effort. This paper presents a new mechanism that supports implementing agent applications by creating troops of agents using wrappers. This solution requires little extra support from the agent system, and ...
    • 3D visualization of weather forecasts and topography 

      Skotnes, Harald; Hartvigsen, Gunnar; Johansen, Dag (Research report; Forskningsrapport, 1994-09)
      Advances in computing power and graphics have increased the use of graphics in weather forecasting. This includes 3D animation sequences and geographical information systems. The paper addresses the main problems and presents preliminary results of the visualization of atmospheric models in conjunction with the underlying topography. The goal is among others to make a sort of 3D satellite pictures ...
    • Separating mobility from mobile agents 

      Marzullo, Keith; Lauvset, Kåre J.; Johansen, Dag (Research report; Forskningsrapport, 2001-01-16)
      In this paper we argue that the traditional model of a mobile agent provides a poor programming structure. We base our argument on our experience since 1993 in building distributed applications and mobile agent platforms. We have observed that every distributed applications contain three distinct aspects, which we call function, mobility and management. Separating an application into these three ...
    • Performance isolation and adaption in the Vortex Kernel 

      Kvalnes, Aage; Renesse, Robbert van; Johansen, Dag (Research report; Forskningsrapport, 2003-01-10)
      Vortex is a new multiprocessor operating system kernel intended for emerging Internet service applications. The architecture is based on SEDA's staged computational model. Vortex provides mechanisms for performance isolation and dynamic adaptation. Performance results validate that the resource control mechanisms of Vortex are effective, and that Vortex significantly outperforms Linux on single-threaded ...
    • Continuation-passing enactment of distributed recoverable workflows 

      Weihei, Yu; Yang, Jie (Research report; Forskningsrapport, 2006)
      Scalability, reliability and adaptability are among the key requirements for the enactment of distributed workflows. In addition, system resources should be efficiently utilized. Central workflow engines and static analysis of workflow specifications are some of the important obstacles to meeting these requirements. We propose a fully decentralized approach to workflow enactment that is not subject ...
    • Increased scalability of the StormCast distributed application 

      Farsi, V. (Research report; Forskningsrapport, 1994-09)
      Scaling is recognized as a primary concern in developing distributed applications. Scaling problems occur when an application reach its upper boundary in some way or another. This paper describes the considerations made in the redesign of the StormCast distributed application to achieve more scalability. Naturally, there can be many factors that restrict a system's scalability. The challenge meeting ...
    • Arctic beans containers composition of non-functional services using composition filters 

      Yang, Jie; Blair, Gordon S.; Andersen, Anders (Research report; Forskningsrapport, 2005)
      It is becoming clear that modern middleware platforms must provide both deploy-time configuration and run-time reconfiguration to accommodate rapid changing requirements and also to be able to operate in dynamic environments. J2EE is a key example of a middleware architecture that supports enterprise applications via its Enterprise JavaBeans (EJB) component model. EJB provides limited configurability ...
    • FirePatch. Secure and time-critical dissemination of patches 

      Johansen, Håvard; Rennesse, Robbert van; Johansen, Dag (Research report; Forskningsrapport, 2006)
      Because software security patches relay information about vulnerabilities, they can be reverse engineered into exploits. Tools for doing this already exist. As a result, there is a race between hackers and end-users to first obtain patches. In this paper we present and evaluate FirePatch, an intrusion-tolerant dissemination mechanism that combines encryption, replication, and sandboxing such that ...
    • Satellite communication applied in a distributed application 

      Farstad, Werner; Johansen, Dag; Hartvigsen, Gunnar (Research report; Forskningsrapport, 1994-12)
      The paper describes the development of a prototype application for access to vital weather information from the Northern Atlantic sea region. The application gives meteorologists access to weather observations measured on sea vessels. Today the available information is very limited. On a daily basis, only 4-5 weather observations in the whole arctic sea-region are conducted. It is therefore suggested ...
    • The xTrans Transaction Model and FlexCP Commit Protocol 

      Arntsen, Anna-Brith (Research report; Forskningsrapport, 2006)
      Traditionally, transactions are flat and atomic possessing the ACID properties. The traditional ACID transaction model has clear limitations in new application domains where transactions often are long-running and require properties that go beyond ACID. Structuring a long-running transaction as an ACID transaction will impede both performance and concurrency. To meet extended and varying transactional ...