We make some observations concerning the set C*n of real nonnegative, symmetric and diagonally dominant matrices of order n. This set is a convex cone and we determine its extreme rays. From this we derive different results, ...

This research has been initiated on the basis of practical experiences in developing a relatively large SGML system at the University of Oslo. This thesis contributes to the field of information systems, with a particular ...

As originally published by John Wiley & Sons, Ltd.

This paper investigates and formally compares the expressive power of dimensional (i.e., spatial, temporal, and spatio-temporal) query languages, where the dimensional extensions are supported in terms of ADTs (abstract ...

Denne oppgaven diskuterer utnyttelse av SCI i et system for distribuert fellesminne implementert i software. Foruten å benytte SCI som et medium for rask meldingsutveksling, er også muligheten for å skrive direkte til ...

Originally, beamforming meant forming the transmit beam for some purpose. Today, we use the word beamforming both for the transmit – and the receive beam. The beam is simply the mainlobe of the array’s radiation – or ...

This doctorate thesis is an exploratory study of distributed and computer-mediated collaborative learning. The work lies in the intersection of the research domains: Computer Support for Collaborative Learning (CSCL) and ...

An important problem in image analysis is to segment an image into regions with different class-labels. This is releveant in applications in medicine and cartography. In a proper statistical framework this problem may be ...

This thesis presents a formal model of object-oriented concepts; in particular we focus on the concepts found useful by experienced designers of reusable software components. The value of the formal model is shown by ...

This document gives an overview the standard methods used to model and analyze the performance of queuing systems. This includes both analytical techniques and simulation methodology. Simulation must be used when the ...

A discrete-event simulation environment, called GMSim, based on the generalized semi-Markov process (GSMP) framework is described. The tool is completely generic and extendible by Tcl script programming. Application specific ...

Sparse arrays provide a large aperture with few elements. Through an exhaustive search of all possible thinning patterns for small linear sparse arrays, the Fourier properties of arrays with optimal coarray properties are ...

All work needs to be articulated in terms of “Who should do what, how, when and where”, and this becomes more complicated as more actors are involved. The use of computers in cooperative work implies new needs for articulations ...

Helt siden midten av 60-tallet har man forsøkt å lage elektroniske pasientjournaler,men arbeidet har vist seg å være overraskende vanskelig. I dag beskrives en elektronisk journal fortsatt som en fremtidsvisjon for de ...

We study the concept matrix majorization: for two real matrices A and B having m rows we say that A majorizes B if there is a row-stochastic matrix X with AX = B. A special case is classical notion of vector ma- jorization. ...

This paper describes some of the problems encountered when trying to hyphenate Norwegian automatically. Two particular approaches are described and compared: the TEX algorithm and the neural network program developed at ...

Given a graph G with a specified root node r. A spanning tree in G where each node has distance at most 2 from r is called a 2-hop spanning tree. For given edge weights the 2-hop spanning tree problem is to find a minimum ...

The analysis of chaotic time series requires proper reconstruction of the state space from the available data in order to successfully estimate invariant properties of the embedded attractor. Using the correlation dimension, ...

Sammendrag Denne hovedoppgaven er et resultat av et ønske fra Sverre Holm og Nils Christophersen om å få mer kunnskap om egenskapene til de høyoppløselige parametriske stråleformingsmetodene MUSIC og ESPRIT. Både forskjeller ...

There is a need to use object orientation to analyse work practices. This should be done based on a social theory on how computers mediate the work arrangement. This paper presents a conceptual framework based on activity ...

Real-time 2D ultrasound systems are used routinely in every hospital and are a huge success both technically and commercially. This paper discusses the signal processing problems that needs to be tackled in order to move ...

This article describes StarTEX, a new TEX format for students writing their first report and other novice users. Its aim is to provide a simpler and more robust tool for users with no previous knowledge of TEX and LATEX.V

We give a purely syntactical, equational characterization of the poly-time functions on any constructor data structure (free algebra). The equations defining a function f have the shape of simple patterns: (f (c y1 : : ...

We de ne a specialization inheritance mechanism for object-oriented programming, admitting covariant rede nition of both methods and instance variables in subclassing. We investigate on the semantic weakness that makes ...

There is an increasing need for analysing problematic situations and creating visions for computer systems that are getting used as means of communication and coordination of work in and between work practices in an ...

In this paper. we present a method used to calculate the acoustic field created by a transducer. A parallel computer network was used to elaborate the effectiveness of the direct calculation of the Rayleigh Integral.

Sammendrag Oppgaven innledes med en innføring i noen grunnleggende begreper innen akustikken,og nevner noen fundamentale relasjoner og karakteristiske fenomener.En gjennomgang av publiserte eksempler på bruk av matematisk ...

to appear in Proc. IEEE Ultrasonics Symp., San Antonio, Texas, November 1996

Computer systems are increasingly being used for communication and coordination of work, while object-oriented modelling techniques aim at modelling the problem domain of the computer system. Current techniques have been ...

This thesis is about document systems used in public case processing work. It explores the subject of documents in document production and handling systems. Through a case study, I explore the role of the genre of a specific ...

Denne hovedfagsoppgaven er basert på et reelt problem ved den parametriske sonaren på Forsvarets Forskningsinstitutts forskningsskip H. U. Sverdrup. Sonarens mottakende frekvensområde 500-5000Hz er overlagret med ...

ABEL is a wide spectrum language developed at the University of Oslo. The applicative core of ABEL is a typed first order language with subtypes and partial functions. The paper presents a constructive fragment of the core, ...

When trying to learn about a group of users, a researcher will interpret their behaviour on her or his own background, achieving an outside understanding. Inside understanding means to know how the people ...

“Abstraction” is used both for denoting relations in the problem domain of an information system, and for denoting relations inside software and hardware of a computer. This calls for a clarification of the concept, such ...

We discuss how the 1'st order specification and programming language ABEL could be extended with higher order functions. Several issues arise, related to subtyping, parameterization, strictness of generators and defined ...

Techniques for analysis aim at diminishing the gap between users' concepts of the problem domain of computer systems and the computers' requirements for algorithmic and structural precision. This paper aims at improving ...

Abstract of M.Sc. thesis Jo Erskine Hannay; August 1, 1995 The thesis deals with topics in the field of formal abstract specification and verification of pro-grams,particularly within the framework of algebraic methods ...

As application systems live longer and grow in size and complexity, there is an ever increasing need for methodologies, models and tools that can aid software builders in developing maintainable, correct and consistent ...

In medical ultrasound imaging, beam control methods such as dynamic focusing, and dynamic aperture and weighting give a need for more flexible control over the receive beam. In addition the desire to increase acquired ...

Certain deterministic non-linear systems may show chaotic behaviour. Time series derived from such systems seem stochastic when analyzed with linear techniques. However, uncovering the deterministic structure is important ...