• Naturvitenskapens grunnlag og begrensning. Seminarrapport 

      Thorvaldsen, Steinar (Research report; Forskningsrapport, 1979)
      Foredrag av Arthur E. Wilder-Smith og Udo Middelmann holdt ved NTH i 1979
    • 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 ...
    • 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, ...
    • 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 ...
    • 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 ...
    • 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 ...
    • 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 StormCast API. Specification of software interfaces in StormCast 2.1 

      Hartvigsen, Gunnar; Johansen, Dag; Farsi, Vahid; Farstad, Werner; Høgtun, Bente; Knudsen, Pål (Research report; Forskningsrapport, 1994-12)
      This report presents the software architecture in the StormCast meteorological workbench. The focus is on the software interfaces in StormCast version 2.1. For each layer in the architecture the functionality, the call structure, the interfaces, the event diagrams and test data are described. In addition, further works are discussed. The identication of software interfaces are based on the StormCast ...
    • File repository transfer protocol. Version 1 

      Stabell-Kulø, Tage (Research report; Forskningsrapport, 1995-02)
      This document presents and specifies the protocol that interfaces clients and servers in the File Repository (FR). The FR is a software system that supports sharing of files. The protocol is modelled after Smtp and Nntp and is encoded in Ascii. No details of server implementation is visible in the protocol description, but we state our intentions at several occasions.
    • Secure communication in FRTP 

      Stabell-Kulø, Tage (Research report; Forskningsrapport, 1995-02)
      To ensure privacy, users of the File Repository Transfer Protocol (Frtp) may require that communication partners are properly authenticated. If one partner wants the communication to be crypted, the other must honor the request. This report describes how authentication and privacy are realized. It is shown, by means of an authentication logic, that the protocol achives its goal in this respect.
    • Performance experiments with the Storm View Distributed Parallel Volume Renderer. 

      Asplin, Jo; Johansen, Dag (Research report; Forskningsrapport, 1995-06)
      Volume rendering is a useful but cpu-intensive method for visualizing large scalar fields. The time to render a single image may be reduced by parallel processing. This paper reports on performance experiments with the StormView volume renderer, which is parallelized on a set of 57 MIPS / 17 MFLOPS workstations connected by a 10 Mbps Ethernet. For certain user patterns, we show that our parallelization ...
    • An introduction to the TACOMA distributed system. Version 1.0 

      Renesse, Robbert van; Johansen, Dag; Schneider, Fred B. (Research report; Forskningsrapport, 1995-06)
      This report briefly introduces TACOMA Version 1.0. This distributed system supports agents, computations that can roam the internet. The report presents the TACOMA project, the computational model, how to get started, and the basic TACOMA abstractions.
    • On the design of a generic object adaptor 

      Eliassen, Frank; Hanssen, Øyvind (Conference object; Konferansebidrag, 1995-08)
    • Efficient bill-of-materials algorithms 

      Beeri, Catriel; Khalaila, Ahmad; Eliassen, Frank (Research report; Forskningsrapport, 1996-09-01)
      It has been shown that every linearly recursive database query can be expressed as a transitive closure possibly preceded and followed by relational algebraic operations. A large class of such queries computes the bill-of-materials of database relations. This paper presents efficient sequential and distributed algorithms that compute the bill-of-materials of a database relation. These algorithms ...
    • Mobile software on mobile hardware. Experiences with TACOMA on PDAs. 

      Jacobsen, Kjetil; Johansen, Dag (Research report; Forskningsrapport, 1997)
      In this paper, we present experiences from adding software mobility to mobile, hand-held computers. In particular, we have built TACOMA Lite, a mobile code system, for this environment. With TACOMA Lite installed, hand-held computers can host and execute mobile code. TACOMA Lite has been used as platform for several mobile code applications. Through experience with these applications, we have derived ...
    • On the design and performance of the PARFUM Parallel Fault Tolerant Volume Renderer 

      Asplin, Jo; Mehus, Sindre (Research report; Forskningsrapport, 1997-01)
      Volume rendering is an important and CPU-intensive technique for visualizing large scalar fields. In essence, a volume renderer performs two activites on behalf of the user: loading a new data set, and rendering the current one. At one level, the performance of an individual activity is important. At another level, the erformance of the session as a whole, in particular switching from one activity ...
    • Security in the PASTA project 

      Stabell-Kulø, Tage (Research report; Forskningsrapport, 1997-02-04)
      This paper presents the system model for the work on security in the Pasta project. We present the objectives of the security effort, the threats we will consider, and those we will not consider. As such, the paper describes the environment which applications must be prepared to face, and still provide users with the desired degree of privacy.
    • An efficient bill-of-materials algorithm 

      Khalaila, Ahmad; Eliassen, Frank (Research report; Forskningsrapport, 1997-04)
      A large class of linear recursive queries compute the bill-of-materials of database relations.This paper presents a novel algorithm that computes the bill-of-materials of its argument's (database) relation. The algorithm uses a special join operation that accumulates the cost of composite parts, without constructing the transitive closure of the argument relation, thus saving time and space. We ...
    • Quick- instead of Merge-sort for pipelines systems 

      Khalaila, Ahmad H.; Eliassen, Frank (Research report; Forskningsrapport, 1997-05)
      This paper proposes an external sorting algorithm for large data as an alternative to the widely used merge-sort algorithm. The algorithm we present is an application of the widely known quick-sort algorithm to large sequences of data stored externally on a disk device. The problem with the merge-sort algorithm is not its time complexity but the large amount of time it requires to output its first ...
    • QoS applied to security in mobile computing 

      Fallmyr, Terje; Stabell-Kulø, Tage (Research report; Forskningsrapport, 1997-06-30)
      Hand-held mobile computers have the potential to become important communication tools for roaming users. As such, they will also become very personal. They will be used under a wide range of operating conditions, and tight user control will be enforced on issues like power consumption, consistency control, and trust management. Their ability to adapt will be the key to their success. In this paper ...